university of wales, newport · ac knowledgements i would like to take this opportunity to express...
TRANSCRIPT
University of South Wales
2064744
FACTORS AFFECTING THE
CLARIFICATION OF COLLIERY
WASTEWATER
BY
ENOCH EDUSEI, M.Sc.
THESIS SUBMITTED TO THE C.N.A.A. IN PARTIAL FULFILMENT
OF THE REQUIREMENTS FOR THE DEGREE OF DOCTOR OF PHILOSOPHY,
DEPARTMENT OF CHEMICAL ENGINEERING
THE POLYTECHNIC OF WALES
TREFOREST, PONTYPRIDD
MID-GLAMORGAN,
WALES, U.K.
IN COLLABORATION WITH THE NATIONAL COAL BOARD (N.C.B.)
SEPTEMBER, 1984.
DECLARATION
This is to certify that neither this thesis nor any part
of it has been presented or being concurrently submitted
in candidature for any other degrees.
Candidate
Dated. September, 1984.
CERTIFICATE OF RESEARCH
This is to certify that, except where specific reference
is made, the work in this thesis is result of the
investigation of this candidate.
Candidate
Director of Studies
Dated. September, 1984
AC KNOWLEDGEMENTS
I would like to take this opportunity to express my
sincere gratitude to Dr. C. Davies and Dr. G.J. James for
their guidance and supervision in all respects over the course
of this research work.
I wish to thank the Staff at both N.C.B.
Laboratory, Pontypridd, and those at the South Celynen
Coal Mines for supplying the colliery wastewater.
My sincere appreciation is also due to all the technical
staff of the Department of Chemical Engineering for their
help in the construction and maintenance of the experimental
apparatus, and also to Mr. S. Lewis and Mr. G.S. Virdi.
I am also thankful to the technical staff at the
Department of Mechanical and Production Engineering for
allowing me to use their Microscopy Laboratory.
I do acknowledge the help of the Chemistry and"Physics
sections of the Department of Chemistry for the use of X-ray
diffraction, Scanning Electron Microscope and Perkin-Elmer
Spectrophotometer equipment.
Finally I do appreciate the endurance and patience of
my family during the preparation of the thesis.
NOMENCLATURE
A Cross sectional area of the electrophoretic cell
D Dielectric Constant
E Potential Gradient
I Current in the electrophoretic cell
M Magnification ratio between the monitor screen and the magnitude of the objective lens.
R Resistance of the substance in the electrophoretic cell
V Voltage across the electrophoretic cell
X Distance travelled by the particles as observed on the television screen
1 Effective length between the electrodes
t Time taken to travel the distance on the television screen
u Velocity of the particles
x Distance travelled by the particles in the electrophoretic cell
^ Electrical conductivity
JUL Electrophoretic Mobility of the particles
v Viscosity
| Zeta potential
(m2 )
(Volt m
(Amp)
(ohm)
(volt)
(m)
(m)
(s)
(ms' 1 )
(m)
(ohm m )
(m volt s )
(Kg m~ 1 s~ 1 )
(volt)
(ii)
FACTORS AFFECTING THE CLARIFICATION OF COLLIERY WASTE-WATER
ENOCH EDUSEI, M.Sc.
ABSTRACT
Investigations were initially carried out to characterize the materials present in shape, mineralogical and chemical composition, and particle size distribution.
A micro-electrophoresis apparatus was constructed to determine the electrokinetic parameters of the colliery waste-water.
The origin of the surface charge which forms on minerals immersed in water is important in flocculation. The nature of the charges on the fines were determined to be both positive and negative. This could be due to the coating of the particles by the addition of the froth flotation reagent used.
The electrophoretic mobilities of the particles were measured at the various pH values and at different depths within the electrophoretic cells. These values of the electrophoretic mobilities were used to calculate the values of the zeta potential by the application of Smoluchowski s equation.
The iso-electric point (IEP) and the zero point of charge (ZPC) were also investigated and found to coincide at all the different levels of depth within the electrophoretic cell . successfully
Finally the colliery waste-water was clarified^by flocculating it using the polyacrylamide solution.
(iii)
CONTENTS
PAGE NO.
Acknowledgements
Nomenclature . .
Abstract ....
i
ii
iii
CHAPTER 1 INTRODUCTION
CHAPTER 2
2.1
2.2
2.2.1
2.2.1 .1
2.2.1 .2
2.2.1 .3
2.3
2.4
2.5
2.5.1
2.5.2
2.5.3
2.6
2.6.1
LITERATURE SURVEY 9
Introduction .............. 10Solid-liquid separation Processes ... 11
The Concept of Sedimentation in the Solid-liquid separation processes ... 12
Factors affecting the sedimentationprocess ................ 14
Settling characteristics of suspendedsolids ................. 14
Selection of the solid-liquidseparation process ........... 15
The Clarification Process ....... 16
Characterisation of particles suspendedin liquids ............... 17
Surface Chemistry applied to Solid- liquid separation processes ...... 20
Surface Chemistry of colloids in connection with stability in solid-liquid separation processes .......... 21
The Electrical Double layer - (The ionic double layer).............. 25
Modification to the Gouy-Chapman Theory. 26
The Electrokinetic Phenomena ...... 29
Direct Applications of Electrokinetic Phenomena ............... 30
(iv)
PAGE NO.
2.6.2 The Zeta Potential - MobilityRelationship for constant dielectric constant and viscosity ......... 32
2.6.3 The Zeta Potential - MobilityRelationships and the variation ofdielectric constant and viscosityin the diffuse layer .......... 33
2.6.4 The Variability of the Dielectricconstant and viscosity in the electrical double layer .............. 34
2.6.5 The Applications of Microelectro-phoresis ................ 35
2.6.6 The Electrokinetics of Clay-WaterSystems ................ 36
2.6.7 The Electrokinetics of Coal suspension . 37
2.7 Flocculation .............. 38
2.7.1 The application of zeta-potential datato Flocculation Studies ........ 42
2.7.2 The application of zeta-potential studies to coagulation of mineral suspensions .............. 44
2.7.3 The Zeta-potential studies on the adsorption of metal cations at the mineral water interface ........ 46
2.7.4 The Application of Zeta-Potential data to the study of selective flocculation .............. 47
2.8 Conclusion ............... 48
CHAPTER 3 PHYSICO-CHEMICAL PROPERTIES OF THE 53COLLIERY WASTE-WATER
3.1 Introduction .............. 54
3.2 The Physical Properties of the Collierywaste-water .............. 56
3.3 The Particle Size Measurement ..... 59
3.3.1 Optical Microscopy in Particle SizeMeasurement .............. 59
3.3.2 Scanning Electron Microscopy (SEM) inParticle Size Measurement ....... 60
(v)
PAGE NO,
3.3.3 The Electrical Sensing zone method of Particle Size Distribution - The Coulter Principle - ....... 61
3.4 The Chemical Analysis of the CollieryWaste-water. .............. 62
3.5 Mineralogical Analysis of fines inColliery waste-water .......... 64
3.6 Thermal Analysis of the Clay minerals. . 65
3.7 Heavy Liquid Density GradientFractionation. ............. 66
3.8 Fractionation by Gravity Settling(Pipetted Method) ............ 67
CHAPTER 4 DESCRIPTION OF APPARATUS 68
4.1 Introduction .............. 69
4.2 Micro-electrophoresis. ......... 70
4.2.1 Micro-electrophoretic Cell design ... 71
4.2.2 Optical System of Micro-electrophoresis. 73
4.2.3 Electrical System of Micro-electrophoresis. ............ 73
4.3 A modified micro-electrophoresisApparatus for Electrokinetic measurementsof the Colliery waste-water. ...... 74
4.3.1 Design and Construction of the Micro-electrophoretic Cell .......... 75
4.3.2 Optical Set up ............. 79
4.3.3 Electrical System. ........... 81
4.4 Electrophoretic Mobility of Quartz ... 81
4.5 Variation of pH with conductivity. ... 82
CHAPTER 5 EXPERIMENTAL STUDY 84
5.1 Introduction ............... 85
5.2 Reagents & Preparation of Samples ... 86
5.3 Safety Precautions ........... 88
5.4 Experimental Procedure ......... 89
(vi)
PAGE NO,
5.4.1 Electrophoresis of the solid fines in the suspension obtained from the Colliery waste-water ........ 89
5.4.2 Electrophoresis of Quartz Suspension . . 91
5.4.3 Flocculation of Solid Fines in theSuspension (Colliery waste-water) .... 92
5.4.4 The Cleaning of the Apparatus. ..... 92
5 . 5 Analytical Procedure .......... 93
CHAPTER 6 INTERPRETATION OF DATA 97
6.1 Introduction .............. 98
6.2 The Concepts of Electrophoreticmobility ................ 99
6.2.1 Smoluchowski ' s Equation ........ 102
6.2.2 Huckel's Equation. ........... 103
6.2.3 Henry's Solution to the contradiction between Smoluchowski and Huckel Theories ................ 104
6.3 Conduction Effects in Electrophoresis. . 106
6.4 The Influence of the Deformationof the Electrical Double layer upon Electrophoresis .......... 109
6.4.1 Effect of Electrophoretic retardation. . Ill
6.4.2 Relaxation effect. ........... 112
6.5 Dielectric constant and viscosity. . . . 114
CHAPTER 7 RESULTS AND DISCUSSION 116
7.1 Introduction 117
7.2 Electrophoresis of lOOppm QuartzSuspension ............... 118
7.3 Electrophoresis of Colliery Waste-water- HC1 ................. 133
7.4 Variation of pH with Mobility andZeta Potential - HC1 .......... 146
7.5 Electrophoresis of Colliery Waste-water - H2SO4 . ............. 172
7.6 Flocculation of Colliery Waste-water- HC1 and Polyacrylamide ........ 204
(vii)
PAGE NO.
CHAPTER 8 CONCLUSION 208
REFERENCES 214
APPENDIX A - Physico-Chemical PropertiesColliery Waste-water ....... Al
B - Electrophoresis of lOOppmQuartz Suspension - HC1. ..... A22
C - Electrophoresis of CollieryWaste-water - HC1. ........ A35
D - Electrophoresis of CollieryWaste-water - HSO- ....... A71
(viii)
FACTORS AFFECTING THE CLARIFICATION
OF COLLIERY WASTE-WATER.
CHAPTER
-1-
INTRODUCTION
The objective of this research is to obtain
fundamental data on the properties of the colliery fines
remaining in the colliery waste-water after the coal has
been subjected to the conventional washing operations at
the South Celynen Coal Mines Newbridge, South Wales. The
data may then be applied to optimize the clarification of the
waste-water. The clarified discharge would minimize river
pollution in this area.
Most contaminants in waste-water are solid particles
and many of these solid particles are stable colloids.
Consequently the treatment of the waste-water requires
effective solid-liquid separation. Furthermore, coagulation
or flocculation which involves the chemical destabilization
of particulates and the physical transport of the destabilized
particles to form larger aggregates is an essential component
of all waste-water treatment systems '.
The most important and the most overlooked characteristic
of waste-water particulate matter is its size.
Particle size determines the transport of materials in
solid-liquid separation processes. Surface area influences
the chemical reactions of particles including interactions
with flocculants and coagulants and adsorption contaminants.
The science of particle size is related to both particle
geometry and surface interaction with the surrounding fluid.
-2-
Quantitative knowledge of the geometric and chemical
properties of particles provide the basis for the design of
a solid-liquid separation process. In practice, theory has
not been developed sufficiently and empiricism still continues
(2 ) to play an important role ' .
Interaction between fluid and particles is a complex
process which is highly dependent on particle size and shape.
Surface effects become increasingly important as particles
decrease in size and develop large surface area.
A precise definition of particle size requires the
knowledge of the boundary surface which separates the particle
from its surroundings '. Where strong crystalline or
intermolecular forces are involved, it is relatively simple
to differentiate particles from their background. But where
there are weak interactions such as with clay, silica gel and
aluminium and iron hydroxides in aqueous slurries, it is more
difficult to decide where a particle terminates and the
surrounding fluid begins. Shearing forces and their relation
to particle break-up are important in differentiating between
strong and weak particles. Shearing forces easily remove
liquid from contact with the particle surface where the fluid
is loosely attached to the solids and the energy barriers are
small. With fragile materials it is necessary to resort to
indirect methods of size analysis. Particle degradation can
often be damaging to the efficiency of industrial solid-liquid
separation processes. Centrifugal pumps, transportation of
fluidized coal and minerals, mixing of flocculants with slurries
-3-
can all lead to particle break-up.
It is the objective of particle science to translate
microscopic properties of statistically significant groups
of particles into macroscopic properties of the systems
which may be dispersed (slurries) or packed (cakes or beds).
Properties of particulate systems relate to the nature
of individual particles and to their mutual interaction in
concentrated suspension. Analytical methods stress the
importance of dispersion and isolation of individual members
of ensembles so that each can be measured independently.
Important as characteristics may be for single particles, the
nature of closely packed particles in beds is of equal or
greater significance in separation operations.
A slurry may consist of a mixture of individual particles
and agglomerates. Sedimentation behaviour is a function ofof
the actual stateyy agglomeration. Thus particle analysis would
not yield information pertinent to the design of a clarifier
Reflecting the problem of definition and the widespread
appearance of particles in diverse systems terms such as silt,
gravel and dust are encountered.
Large particles can easily be observed visually and the
laws of geometry can be applied. If the size reaches the
molecular range, statistical mechanics can be used to describe
the system. In the intermediate range of colloidal and fine
particles, no universally satisfactory method is available
to define the system.
-4-
The particle distribution in most solid-liquid
suspensions encountered in industrial applications extends
over several orders of magnitude. The removal of a significant
proportion of the large particles is accomplished relatively
easily by screening or sedimentation. However, fine particles
cannot be removed efficiently by such methods. For a successful
separation by sedimentation, aggregation of fine particles
into large more readily settleable aggregates is essential.
The rate of aggregation and the nature of the particle
concentration and types of electrolytes, flocculants and
pH., Bodman et al. ' found experimentally that the settling
rate of suspensions of titanium oxide (TiO^) in water is a
strong function of pH, salt concentration and flocculating
agent concentration. Coagulation is also used to assist in
other solid-liquid separation methods.
When two phases are in contact, as in a suspension (solid-
(4) liquid) there develops a difference in potential between them v ;
When one of the phases is caused to move tangentially past
the second phase thereare observed a number of phenomena which
are grouped under electrokinetic effects. There are four
distinct effects depending on the way in which the motion is
induced and they are; electrophoresis, electro-osmosis,
streaming and sedimentation potential.
In most electrokinetic pheomena a fluid moves with
respect to a solid surface; the exception is electro-osmosis.
This thesis will be concerned with the determination of the
relationship between the velocity of the fluid and the electric
-5-
field in the interphase region. The electric field will be
partly determined by the surface charges on the solid and in
the liquid but may also include an externally imposed field.
The relationship between the potential or the electric
field at any point and the number of charges is given by the
Poisson equation. The charges themselves will respond to
three sorts of forces: electrical potential, the diffusion
force tending to smooth out concentration variations and the
bulk movement of charge carried along by the flow of the
liquid (convective transport).
Even using vector calculus and high-speed computer
solution of the resulting differential equations it is necessary
to make a number of significant simplifications to treat highly
(4) idealized models of the real experimental conditions '.
Theoretical treatments generally assume that the solid
is either a sphere, a cylinder or a large flat plate, or
rarely a disc or an ellipsoid. The liquid is assumed to be
(2) Newtonian ', and moving sufficiently slowly so that turbulence
and other non-linear effects are absent.
The most important concept which is introduced is that
of the plane of shear. This is an imaginary surface which is
considered to lie close to the solid surface and within which
the fluid is stationary. In the case of a particle undergoing
electrophoresis the surface of shear forms a sheath which
envelopes the particle. All the material inside the sheath
forms the kinetic unit so that the particle moves along with
a certain quantity of the surrounding liquid and its contained
-6-
charge. Measurement of the electrophoretic mobility
therefore gives a measure of the net charge on the solid
particle.
Analysis of the forces on the solid or the liquid can
be carried out in terms of either charge or electrostatic
potential. In the latter case the calculation of the average
potential in the surface of shear is performed and this is
called the electrokinetic or the zeta potential.
Another limitation of the concept of the surface of shear
is the assumption that the fluid in the neighbourhood of the
surface retains its bulk properties right up to the surface^ ' ' such that the viscosity then becomes infinitely large just
inside the shear surface. This limitation can be replaced by
a less restrictive one, but at the cost of the lack of
definition of the zeta potential. This procedure is justified
because the effect of the electricity on the viscosity
is probably not as large as was first believed. ' '
Many of the important properties of colloidal systems are
determined directly or indirectly by the electrical charge or
potential on the particles. The potential distribution
determines the interaction energy between the particles, and
this is often responsible for the stability of the particles
towards coagulation and flocculation. It is also possible to
correlate the zeta potential with the sedimentation behaviour
of colloidal systems and the flotation of mineral ores^ '.
If the zeta potential is an indicator of the electrical state
of the double layer, then when it approaches zero, sols
-7-
should become unstable and this should lead to clarification
. This has been demonstrated where inorganic
electrolytes have been used to lower the zeta potential of
industrial wastes* ' '.
Despite the limitations of both these procedures they
remain the most valuable available at present. Some recent
(8) developments in the measurement of semi-conductor properties
are very promising and may provide an alternate accepted
technique for measuring total double layer potentials.
(9) Work up to the early 1950's has been reviewed by Overbeek v '
and this work will be taken as essentially the base line for
this review. There are many situations in which the zeta
potential is used as a parameter in its own right. These
include characterizing the outer diffuse part of the double
layer and hence is valuable for discussing the interaction
between particles or the flow of liquid through membrane pores
or porous plugs.
The importance of zeta potential measurement to an
understanding of the mineral-water interface has been reviewed
by Mackenzie , Haydon ' and Overbeek and on the
properties of the oxide mineral-water interface by Parks * '.
There is still unfortunately a large gap between the
theoretical aspects of the electrical double-layer structure
and the practical application of these theories to industrial
processes.
-8-
LITERATURE SURVEY
CHAPTER 2
-9-
2.1 INTRODUCTION
Clarification involves the removal of solids from a
relatively dilute stream containing difficult to filter
colloidal materials. Frequently, admixes of filter-aids
are added directly to the slurry to reduce the resistance
of the fine particles. This method of clarification thus
involves the study of the solid-liquid separation process.
The solid-liquid separation process involves the separation
of two phases, solid and liquid from a suspension >>***)
It is used in many processes with the aim of :
(a) recovering the valuable solids, (the liquid being
discarded);
(b) recovering the liquid, (solids being discarded);
(c) recovering both solids and liquids;
(d) recovering neither (but for example to prevent
water pollution).
An ideal solid-liquid separation process would result in
a stream of liquid going one way and dry solids the other way.
Unfortunately, none of the separation devices works perfectly/ 2 7 1 P )
. This imperfection of separation can be characterized
in two ways. The mass fraction of the solids recovered is
called the separation efficiency and expressed as a percentage,
whilst the dryness of the solids recovered may be characterized
by the moisture content which is percentage by weight.
-10-
2.2 SOLID-LIQUID SEPARATION PROCESSES
The term filtration implies a narrow concept while
solid-liquid separation designation reflects better the
realities confronting engineers with the need for effecting
separation of particulates from liquids ' ' . Solid-
liquid separation includes a variety of operations ranging
from pretreatment of slurries through thickening to cake
deliquoring.
There are considerable differences in the solid-liquid
separation field since the essential solid-liquid parameters
such as permeability and porosity must presently be obtained
anew for every material. The number of combinations of
satisfactory operations is so large that finding the best
process is difficult.
If the liquid is constrained and particles can move
freely within it, due to fields of acceleration, then the
separation processes are known as sedimentation and flotation
(15,16)^ Tiller* 2 ^, Svarovsky^ 7 ^ Coulson and Richardson^ 15 ^
and Perry ' have discussed all the various methods of solid-
liquid separation processes.
There are certain fundamental concepts which are essential
to the understanding of the solid-liquid separation processes
and among these fields of study are the following:
(a) Particle characterization,
(b) Surface and Colloid Chemistry,
(c) Dynamics of particle-liquid systems.
-11-
Complex solid-liquid separation phenomena frequently
make the mathematical analysis dubious since slurries are
notoriously fickle and change with time and treatment .
2.2.1 THE CONCEPT OF SEDIMENTATION IN THE SOLID-LIQUID SEPARATION
PROCESSES.
Sedimentation is the separation of a solid phase from the
liquid phase resulting from an external force (gravity settling)
exceeding the magnitude of the frictional forces^ ' »15,16, 5)^
It may be divided into two functional operations of thickening
and clarification. The primary purpose of thickening is to
increase the concentration of a relatively large quantity of
suspended liquids in a feed stream. Clarification is to
remove a relatively small quantity of fine suspended particles
and to produce a clear effluent. Both these functions are
related and the terminology merely makes a distinction between
the process results desired. Gravity thickening requires much
higher torques than clarification, and clarifiers frequently
require the inclusion of flocculating devices to assist in the
(coagulation or flocculation) clarification of dilute streams.
Complications arise in sedimentation depending upon the
particle shape and size and the variable surface charges. The
effects of other factors such as convection currents and
particle-particle interactions are also evidenced ' '. One
simplification in the analysis of heterogeneous systems such
as these encountered in water and waste-water treatment is to
-12-
assume average properties and conditions for sedimentation.
Particle size, particle density and fluid viscosity are
factors to be considered in any sedimentation process* ' '.
Materials with particle diameters of the order of a few
microns settle too slowly for most practical operations.
Such particles may be agglomerated or flocculated into relatively
large clumps which can settle out more rapidly.
The settling of discrete particulate masses based
initially on the modifications of Stokes* law has featured
in the researches of many workers with as many different
solid-liquids systems ' .
( 22 ) Wallis ' attempted to bring together the results obtained
from a variety of conditions to categorize the behaviour of
settling sediments of uniform particles greater than one-
hundred microns sufficiently large for anomalous viscosity
effects and flocculation to be regarded as negligible.
Four zones have been observed to develop during/ O O o jr \
sedimentation ' . They were supernatant, suspension,
sediment in compression and compacted sediment. Some authors
preferred to break the compression zone into two and notably
(.24) among these are Coe and Clevenger ' .
The overall process time depends on the type of settling
aid used.Coagulants may give process times of several hours
but certain acrylic-based polymer flocculants can achieve
process times of a fraction of this * . Process requirements
and cost are therefore very important considerations in the
selection of a settling-aid. Spherical and quite compact
-13-
floes can often be achieved by the application of a
combination of electrolytes and polyelectrolytes. Such
floes are not only denser and faster settling but also
entrain less of the suspending liquid and hence produce a more
distinct separation.
2.2.1.1 FACTORS AFFECTING THE SEDIMENTATION PROCESS
The most important factors affecting the rate and the
mode of settling of aqueous particulate suspensions are:
(a) the nature of the particles: size distribution,
shape, specific gravity, chemical and
mineralogical properties;
(b) the proportion of solids and liquid forming the
suspension and concentration effects;
(c) the type of pretreatment: chemical conditioning
and flocculation;
(d) the type of containing vessel: size shape and
wall effects.
2.2.1.2 SETTLING CHARACTERISTICS OF SUSPENDED SOLIDS
Suspended solids found in industrial wastes vary
appreciably in size, density and settling characteristics.
Settling rates are also influenced by temperature and viscosity.
The settling characteristics of finer particles ranging
from the micron to sub-micron size are impossible to predict.
Laboratory test are necessary to determine settling
characteristics^ 2 ' 7 ' 25 ).
-14-
Treatment of particles approaching micron size or less
requires an understanding of colloid chemistry. Colloid
stability depends on the forces of repulsion which exceed
the forces of attraction. Properties of colloidal
dispersions can be changed by changing particle size
distribution by crystal growth, by comminution, by adding
electrolytes or surface active agents.
Particle charge is distributed over two concentration
layers of water surrounding a particle. These two layers
are; an inner layer of water and ions which is tightly
bound to the particle and moves with it through the solution,
and an outer layer which is part of the bulk water phase and
moves independently of the particle. Charges of these layers
are not directly measurable but the zeta potential can be
determined indirectly.
2.2.1.3 SELECTION OF THE SOLID-LIQUID SEPARATION PROCESS
The process of gravity sedimentation appears to be the
most suitable to remove the solid fines from the colliery
waste-water.
There are two methods of gravity sedimentation.
Clarification refers to the removal of small quantities of
particles which settle relatively independent of one another,
with the production of a clear effluent with minimal solids.
Thickening is the term used for more concentrated suspension
in which particles undergo hindered settling with the
production of a concentrated underflow.
-15-
From a comparison of these two methods clarification
is the best method for the separation under consideration.
2.3 THE CLARIFICATION PROCESS
Clarification is often a two-stage process. The first
stage is physico-chemical and it involves the conversion of
discrete, unflocculated particles of the suspension into a
(25) thickened underflow with a clear overflow . This step
is capable of a high degree of control, and is efficient,
irrespective of the scale of operation. This reliability
is, however, of vital importance in terms of establishing
the conditions required for a similar effectiveness of the
second stage.
The second stage, predominantly an engineering operation
is to reduce the remaining water content by the transformation
of the thickened fluid into a compact, rigid solid containing
only small quantities of water.
It is widely recognized that whatever form of machinery
which is chosen for the solid-liquid separation process of
clarification the operation can be greatly facilitated by
controlling the state of flocculation of the particles in the
(19) colloidal size range '.
In clarification the suspended particles settle in
( 7) different ways v ':
(a) Hydroseparation or Classification - Each particle
settles separately and at its own rate.
-16-
(b) True clarification - Particles agglomerate into
separated floccules which then settle out.
2.4 CHARACTERIZATION OF PARTICLES SUSPENDED IN LIQUIDS
Particles in suspended liquids are characterized into
primary and secondary properties. The Primary properties
are particle size distribution, shape, density, liquid
viscosity and concentration, surface properties and the
state of dispersion whilst the Secondary properties are the
settling velocities of the particles, the permeability of
(7} the bed and the specific resistance of the cake v '. The
primary properties govern the secondary properties.
As the relationships in solid-liquid separation are
rather complex, the primary particle properties are mainly
used for a qualitative assessment of the behaviour of the
suspensions. The finer the particle size the more difficult
is the separation and the concentration of the solids also
plays an important role.
Characterization of solid particles, most of which are
in practice irregular in shape, is usually made by analyzing
the particle size and its distribution.
Small particles dispersed in a suspension are stabilized
by forces due to the surface charges of the particles. For
this reason, such particles do not agglomerate spontaneously.
Most particles suspended in water such as clay, silica and
hydrated metal oxides possess negative surface charges in
the neutral pH range. Primary surface charges or suspended
-17-
particles are produced by any of three distinct processes
depending upon the composition of the solution and, on the
(2 ) nature of the solid phase .
One source of the surface charges is the imperfections
in a crystal lattice. This source is responsible for a
major portion of the charge on clay minerals^ ' '. The
sign and magnitude of charges produced by isomorphic
replacements of individual atoms are independent of the
characteristics of the aqueous phase. A second source of
surface charges occuring on the particles is the variety of
surface groups which are capable of ionization. The charge
on these particles is dependent upon the extent of surface
group ionization and on the pH of the solution. A third
source of surface charges on suspended particles may arise
from the preferential adsorption of certain ions from solution.
The specific adsorption of these potential determining ions
can arise from hydrogen bonding, covalent bonding or van der
Waals bonding and can be augmented by electrostatic attraction
(1,4,7,26)
Suspended particles are grouped into hydrophobic and
hydrophilic classes. Particles classified as hydrophobic
are not entirely water-repelling but only a few molecular
layers of water are adsorbed at the solution-particle interface.
Hydrophobic particles are stabilized in aqueous suspension
principally by charge. They generally lack stability in the
presence of electrolytes ' '. Hydrophilic particles are
actually slightly soluble macromolecules having a strong
-18-
affinity for water due to the presence of polar groups which
which retain sheaths of water around individual particles.
The various characteristics described above are further
influenced by pH, temperature and concentrations of soluble
salts in the suspending medium. The two most important
characteristics of suspended particles to be considered
relative to any separation process are the size and surface
charge of the particles.
Many authors including Tiller^ ' Svarovsky ' Coulson
and Richardson^ 15 ', Perry and Chilton^ 16 ^ Alien' 7 ' and
(28} Irani have discussed the different techniques and
applications in the measurement of particle size and
di stribution.
The size of a particle is that dimension which best
characterizes its state of sub-division. Various methods
of particle size measurement determine different measures of
size and great care must be taken when making a selection
as to what size is most controlled.
Conversion of size data developed from one set of
particle properties to another can lead to significant errors
and because of this, the particle sizing technique should
(29 ) duplicate the process under evaluation. Cole x ' used the
Quantimet 720 to compare the longest chord, perimeter and
the area for a large number of particles.
-19-
2.5 SURFACE CHEMISTRY APPLIED TO SOLID-LIQUID
SEPARATION PROCESSES
Suspensions of fine particles in liquid media have
properties which cannot be attributed solely to hydrodynamic
factors. Such factors ares
(a) electrophoresis - migration of particles under the
influence of an externally applied
electric field,
(b) stability of suspension under certain conditions,
(c) dependence of stability on concentration(s) and
type(s) of electrolyte(s) as well as on the nature
of the solid,
(d) dependence of stability on pH
(e) agglomeration, coagulation, and flocculation,
(f) repeptization.
These phenomena have their origin in the special physico-
chemical conditions that exist at regions in the intermediate
neighbourhood of solid-liquid interfaces and the interaction
between these regions. Such conditions exist at all solid-
liquid interfaces but their presence becomes primarily
important in solid-liquid suspensions due to the very large
area per unit suspended mass^ ' ' . These phenomena affect
profoundly all stages and facets of solid-liquid separation
methods.
-20-
2.5.1 SURFACE CHEMISTRY OF COLLOIDS IN CONNECTION WITH
STABILITY
The aggregation of colloids is known as coagulation
or flocculation. Previously these two terms were used
interchangeably but nowadays there is a trend to distinguish
between aggregation due to simple ions as coagulation and
aggregation due to polymers as flocculation.
Except under idealized laboratory conditions, colloid
stability is a very complex matter. Several forces can be
operative between colloids; some attractive and others are
repulsive. These forces may react in different ways upon
variations in the conditions such as pH, temperature and
salt concentration^ ' '. In order to understand which forces
are operative, it is necessary to characterize these particles
and especially the surfaces of these particles. Also to be
considered is the rate at which the particle surface properties
can alter relatively to the rate at which two particles
approach each other '. Both static and dynamic properties
require attention. The treatmentof colloid stability is
different for dilute and concentrated sols. In dilute sols
aggregation is a bimolecular process and in concentrated
systems all particles interact simultaneously with several
neighbours.
Charges on dispersed particles are invariably due to an
unequal distribution of ions over the particle and the
surrounding solution. The particle charge and the charge in
solution are equal in magnitude but opposite in sign
-21-
The particle charge and the counter-charge together form an
electrical double layer* 2 ' 4 ' 7 ' 10 » 26 > 3°). The reason why an
uneven charge distribution between particle and solution
arises can be quite different depending on the nature of the
particle' 31 ' 32 ' 33 ' 34 ''
In interfacial electrochemistry, it is customary to
divide the double layer into three parts:
(a) surface layer
(b) Stern layer or molecular condenser which is
defined as that part of the solution side that
is close enough to the surface to be under the
influence of specific effects stemming from the
surface,
(c) a Gouy-layer or diffuse layer which is that
part of the solution side that is far enough from
the surface that specific effects may be neglected.
Tiller ' Hunter ' have discussed the theory of colloid
stability which was developed almost simultaneously by
Derjaguin and Landau in the U.S.S.R and Vervey and Overbeek
in the Netherlands and this is called the DLVO theory of
colloid stability which has also been discussed by many authors
including Mackenzie' 10 ' van Olphen' 26 ' and Lyklema' 30 '. The
validity of this DLVO theory is limited to lyophobic colloids
and simple electrolytes. The term stability when applied to
colloidal dispersions is a relative term used to express the
resistance of the dispersion with time.
The destabilization of colloidal dispersions can be
-22-
(35) accomplished by several different mechanisms. La Mer '
has divided these mechanisms into the following categories:
(a) Process which cause a reduction of the total potential
energy of interaction between the electrical double
layers of two colloidals.
(b) Processes that aggregate colloidal particles into
three-dimensional floe networks by the formation
of chemical bridges.
(35) La Mer ' has designated the first category as coagulation
and the second as flocculation. Stumm and O'Melia ' pointed
out that although certain well understood systems are easily
classified according to these definitions the exact mechanisms
of particle destabilization in water treatment are not
completely classified.
Kuz'kin and Nebera ' have discussed the degree and
stability of numeral suspensions. The study of suspensions
is not detached from colloids since in many respects their
properties coincide with the properties of the finest dispersions,
The following are properties common to both: the presence of
a developed surface, of which the properties and the phenomena
associated with these properties; determine the behaviour of
suspensions; the presence of an electrokinetic and electro
chemical potential at the phase interface; and hydration of
particles. The stability of dispersed systems is one of the
central problems in colloid chemistry.
-23-
Many authors including Tiller^ ' and Hunter 1 have
discussed the Schulze-Hardy rule on the critical coagulation
concentration (C.C.C.). Addition of an adequate amount of
coagulant to a given colloidal dispersion causes coagulation
or flocculation. The minimum concentration above which
coagulation or more precisely destabilization is produced, is
denoted as the critical coagulation concentration.
The stability of lyophobic colloids can be achieved by/ O Q \
one of the following methods* '.
(a) Adsorption of anions or of an anionic polyelectrolyte
on the surface of the colloidal particle to create
strong mutual repulsion due to high zeta potential;
(b) Adsorption of a strongly hydrated hydrophilic
protective colloid on a layer hydrophobic colloid
and this protective action is the most conspicuous
influence of the addition of lyophilic colloids to
lyophobic one,
(c) Adsorption of a non-ionic polymer of sufficient
chain length to create steric hindrance to prevent
two lyophobic particles from coming close enough
to aggregate.
Colloid stability can be either increased or decreased
by adsorbed polymers. If the polymer carries an opposite
charge to the particles then the electrical repulsion is
reduced and the particles can be destabilized. When the
adsorbing material has the same sign of charge as the particles
-24-
repulsion is increased and the particles are stabilized.
There are also many cases where colloidal stability
can be significantly reduced by adsorbed non-ionic molecules/ o f- \
and this is known as sensitization^ ' . This is usually re
lated to a reduced surface charge brought about by the displacement
of polar water molecules from the surface of particles in
aqueous media.
2.5.2 THE ELECTRICAL DOUBLE LAYER-(THE IONIC DOUBLE LAYER)often
The electrical double layer is.the most usual factor in
(37) deciding the stability of aqueous suspensions '. Thus
stability is the result of the electrostatic forces of
repulsion which predominate over the attractive forces of the
(39) particles. Derjaguin and Landau v ' have developed a more
exact theory. The theory of the electric double layer deals
with the distribution of the counter-ions and the co-ions
of a charged surface and with the magnitude of the electric
potentials occuring in this region .
The ionic double layer was developed by Gouy ' ,1 43 \ .. ( 44)
Chapman v , Debye and Huckel v ' and this theory was improved
(45) by Stern ' with the introduction of the concept of the
Stern layer.
(41) (43 } Gouy ' and Chapman v ' independently developed the
so-called diffuse double layer theory of plane interfaces.
The principles which underlie the theory are very similar to
those underlying the theory of strong electrolytes subsequently
-25-
proposed by Debye and HucKel^ . Mathematically the Gouy-
Chapman theory is the simpler since equations have been
developed for planar rather than for spherical symetry.
Several refinements of the Stern theory have been
suggested by many workers including Kruyt^ ' and Sennett
and Oliver^ ' ; the most notable is that of Grahame 1 ' .
However, the Stern model, while it provides a rather simple
picture of a complex phenomenon, mostly displays the properties
of the double layer which have been deduced from experimental
observations .
The ionic double layer has been treated theoretically
by numerous authors including Tiller^ ' , Hunter^ , Svarosky ,
Coulson and Richardson , Shaw 40 ] Adan/ 49 ',and Ross^ 50 ^ at
various levels of detail. Most treatments rest upon the
theories of Gouy and Chapman and of Stern. These two theories
are complementary. Stern modified the Gouy-Chapman model in
order to bring it more into line with reality.(4) Hunter has discussed the potential and charge in the
electrical double layer for the various geometries of a flat
disc sphere and cylinder.
2.5.3 MODIFICATIONS TO THE GOUY-CHAPMAN THEORY
Several assumptions were made in the analysis of the
double layer according to the Gouy^ ' and Chapman^ ' models.
These assumptions are:
(a) the charge on the solid surface is considered
to be uniformly distributed,
-26-
(b) the ions which make up the diffuse layer are
considered to be point charges,
(c) the solvent is a structure-less medium whose
only influence is through its dielectric constant.
Stern recognised the assumptions that the electrolyte
ions could be regarded as point charges and the solvent as
a structure-less medium of dielectric of constant permittivity
were unsatisfactory. This effect is most obvious experimentally
when the measured values of the electrical capacitance of
an interface are compared with theoretically calculated
values '.
Aveyard and Haydon ' have also discussed three of
the important shortcomings in the application of the Gouy-
Chapman diffuse double layer theory. These authors have
also discussed the Stern theory and the molecular capacitor
in the ionic double layer. The dielectric constant in the
Stern layer is well below that of the bulk solution.
Graham ' has attempted to modify the Gouy-Chapman and
Stern theories by taking into account that, in the Stern
layer there may be two types of ions; one of which is
specifically adsorbed, the other being merely a normal
hydrated ion at its distance of closest approach to the
surface. The specifically adsorbed ion is assumed to lose
some of its water of hydration and to be closer to the surface
than the other ion.
-27-
In current theories of the double layer the problem
is alleviated by dividing the space charge in the electrolyte
solution into two regions: the compact or the inner region
is near to the wall in which the charge and potential
distribution are determined chiefly by the geometrical
restriction of ion and molecule size and short range
interactions between ions, the wall and adjoining dipoles.
Also the diffuse layer is further out from the wall where
the Poisson-Boltzmann equation may be expected to give a
reasonable representation of the potential distribution.
The dielectric permittivity has been found to vary over
(4} the compact or inner layer by many authors including Hunter v '
and Aveyard and Haydon^ ' .
The significance of the discreteness of the charge
effect was first recognized by Frumkin ' and the first
(52} calculations of its magnitude were made by Esin and Shikov '.
The importance of the discreteness of charge effect is that it
appears to be able to explain a wide variety of effects which
are not explicable using the simple version of the Gouy-
Chapman and Stern theories.
The calculation of the discreteness effect has been fully( 53 ( 54 reviewed by MacDonald and Barlow v ', Levine et al v ' and
more briefly by Levine^ 5 '.
-28-
2.6 THE ELECTROKINETIC PHENOMENA
An electrical double layer is set up at almost every
phase boundary and associated with this double layer there
is a charge in electrical potential. A practical way to
characterize the double layer is to measure the zeta potential
and several techniques^ ' ' ' ' are available. If two
phases originally uncharged are brought into contact, one
phase assumes a slight positive charge and the other an(49) equal negative charge '.
In any system which contains matter in two phases with
different charges, the application of an electric field
causes one phase to move relatively to the other. The
negatively charged phase moves towards the positive pole and
the positively charged phase towards the negative pole.
This motion is called the electrokinetic movement^ ' ' >10,11,
' ' ' . The rate of relative motion of the two phases
is proportional to the intensity of the applied field. It
also depends on the size and shape of the particulate matter,
on the properties of the fluid, and on the structure of the
double layer particularly on a certain potential called the
electrokinetic or zeta potential.
Electrokinetic phenomena include four distinct processes
namely electrophoresis electro-osmosis, streaming and
sedimentation potential./ g 12)
Overbeek* ' ' and others have reviewed an outline of
the principles of electrokinetic phenomena including the
practical difficulties of measurement.
-29-
The electrokinetic velocity is measurable and
unambiguous. The electrokinetic or zeta potential which
is deduced from the electrokinetic velocity is defined as
the potential at the plane of shear of liquid^ ' ' .
It is necessary to know the position of the plane of shear
in order to attach significance to the zeta potential and
to relate it to the structure of the double layer. Herein
lies the principal difficulty in the interpretation of the
electrokinetic data especially when the double layers are
subject to shearing forces . The electrokinetic problem
can be examined in two parts. Firstly, the conversion of
the electrophoretic mobility into zeta potential. Secondly
is the difficulty in trying to decide where the position of
the slipping plane is located. These two problems are inter
related unless the viscosity in the continuous liquid phase
is constant or has a very large and abrupt discontinuity.
Owing to a lack of knowledge concerning the viscosity of
solutions near the surfaces the hydrodynamic equations have,
until recently, only been solved for constant viscosity in
the liquid phase.
2.6.1 DIRECT APPLICATIONS OF ELECTROKINETIC PHENOMENA
Any process which involved the separation of particles
with the difference in zeta potential suggests itself as
suitable for an electrokinetic separation technique.
-30-
In the field of lyophilic colloids the electrophoretic
separation of proteins and amino acids is common place.
There does not appear to have been much application in the
separation of lyophobic colloids probably because separations
are more easily accomplished by other methods. Electrophoretic
deposition has been applied in several cases '
Ross ' has reviewed a recent study by Todd and Wild
which described a unique separation procedure which is
related in some way to the electrical character of a solid-
liquid interface. This separation procedure was applied to
mineral particles in the range of one to thirty microns and
suspended in non-conducting organic liquids.
Many authors^ ' ' ' have investigated electrophoresis
and the liquid counterflow (electro-osmosis) as a means of
dewatering fine particle size suspension which are amenable
to filtration.
The zeta potential is closely connected with the stability
of lyophobic colloids. If it is reduced below a critical
value the dispersed particles coagulate or flocculate rapidly.
Ions of opposite charge to the colloidal particles are easily
adsorbed and cause coagulation or flocculation. The
effectiveness of the ions increases enormously with increase
in valency according to the well-known Schulze-Hardy rule.
-31-
2.6.2 THE ZETA POTENTIAL-MOBILITY RELATIONSHIP FOR
CONSTANT DIELECTRIC CONSTANT AND VISCOSITY
Of the various forms of electrokinetic phenomena,
particular reference will be made to electrophoresis. Many
authors including Hunter^ ' Mackenzie^ ' Shaw ' Overbeek^ '
(57) and Booth x ' have reviewed the details of derivations and
theory on electrophoresis.
One of the most commonly applicable forms of zeta
potential-mobility relationships have been derived by
Smoluchowski 1 '. Henry^ ' has deduced an equation basedf n\
on a number of simplifying assumptions. Overbeek v ' has
improved Henry's result by introducing the relaxation correction.
This makes an allowance for the deformation by the external
field of the space charge and potential distributions near
the particle and for ionic diffusion. Overbeek also attempted
to avoid the linear approximation of the Poisson-Boltzmann
equation. The neglect of Brownian motion has been shown by
Overbeek^ ' to be justified provided the colloidal particle
is at least ten times the size of the electrolyte ions.
Haydon has reviewed the influence on the mobility
of a non-uniform conductance of the particle which has been
investigated independently by Booth^ 57 ^ and Henry^ 59 ^. The
special interest and importance of this problem is that the
conductance in the surface phase near a particle may be
considerably higher than that in the bulk of the solution.
Pickard has re-examined the basis of electrophoretic
equations and has made several critisms of Overbeek^ 56 ^ and
Booth< 57 >.
-32-
2.6.3 THE ZETA POTENTIAL-MOBILITY RELATIONSHIPS AND THE
VARIATION OF DIELECTRIC CONSTANT AND VISCOSITY IN
THE DIFFUSE LAYER.
The supposition that the ratio of viscosity to dielectric
constant is constant and equal to the value in the bulk phase
is probably unjustified^ ' '. To show conclusively that
this is true is rather difficult. Neither viscosity nor
dielectric constant in the double layer has been measured
directly. Estimates have to be made from a knowledge of
the double layer structure at a selected surface. For such
a system it is sometimes possible to derive from the Known
surface charge or from other sources, the value of the
potential at the physical boundary between a solid and liquid^ '
This potential can then be compared with the zeta potential
calculated on the assumption of a bulk value of the ratio of
the viscosity to the dielectric constant.
To deduce whether the diffuse layer dielectric constant
or the viscosity is responsible for the high values of the
ratio of the viscosity to the dielectric constant in the
diffuse layer is difficult. Evidently this can be caused by
a large viscosity or a small dielectric constant both of
which are possible at high field strengths. There appears to
be no data on the effect of high fields on the viscosity of
water and viscoelectric constant for water. A theoretical
estimate of the viscoelectric constant has been carried out
by Lyklema and Overbeek^ ' . The main effect of the analysis
is to replace the older concept of a well-defined slipping
-33-
plane by a slipping layer in which the viscosity varies
continuously.
2.6.4 THE VARIABILITY OF THE DIELECTRIC CONSTANT AND
VISCOSITY IN THE ELECTRICAL DOUBLE LAYER
Electrokinetic measurements are of considerable interest
for the study of the electrical double layers. Such measurements
are difficult to interpret and have been frequently criticized
by many authors including Hunter^ ' ' Haydon ' and
Lyklema and Overbeek ' on two counts. These were:
(i) the failure to take account of the variations
in the viscosity and dielectric constant owing
to the high field strength in the immediate
neighbourhood of the particles,
(ii) the uncertain!ty in the position of the plane
of shear.
(54) Levine et al ' have criticized the theory on which
Haydon^ ' based his calculation of the surface potential.
Whether it influences the relation between the zeta potential
and electrophoretic mobility depends on the actual value of
the dielectric constant in the outer region of the double
layer. The justification in the use of the bulk value of
the dielectric constant in the electrophoretic equation by
Helmholtz and Smoluchowski was inferred by Lyklema and
Overbeek^ '. Hunter^ 6 ' has reviewed the variation of
permittivity with field strengths; the relation between the
-34-
zeta potential and "Smoluchowski" zeta potential for variable
permittivity but constant viscosity and the influence of
surface charge density on position of shear plane.
2.6.5 THE APPLICATIONS OF MICRO-ELECTROPHORESIS
Electrophoresis is by far the most common procedure for
determining the zeta potential and a large number of different
techniques have been developed for the application to different
kinds of material* 4 ' 10 ' 26 ' 40 . The most important is the
micro-electrophoretic procedure in which the movement of
individual particles under the influence of a known field is
followed directly in an ultramicroscope assembly or dark-
field microscope.
The applications of micro-electrophoresis fall largely
into two classes. Firstly, is the determination of zeta
potential for the purposes of interpreting colloid stabilities.
To apply this approach it is customary to identify the
zeta potential with the potential in the outer Helmholtz
plane and to assume this potential to be the operative potential
in controlling the electrostatic forces between particles
(4,10,11). Recently techniques' 63 ' 64 ' 65 ' 66 ) have been
developed which enable zeta potentials to be measured in media
of low dielectric constant where the low ionic concentrations
can nevertheless cause large surface potentials. It is
imperative to have reliable zeta potential-mobility relations
for all potentials and the shape factor values and to
comprehend the problem of viscosity variations.
-35-
The second application is the investigation of the
nature of particle surfaces, and the greatest interest is
usually in the nature and magnitude of the surface charge.
Tiller^ ' Svarovsky ' Mackenzie^ , Kitchener ' and
van Olphen^ 6 ' and Shavr ' have also discussed the various
applications of micro-electrophoresis.
2.6.6 THE ELECTROKINETICS OF CLAY-WATER SYSTEMS
Electrical properties of clay-water systems are determined
principally by the structure of the electrical double layers
on the clay surface. Although the negative-face double layer
probably plays the major part, possible contributions of the
edge double layer should not be overlooked in the interpretation
of electrochemical and electrokinetic behaviour of the clay-( 2 ft ^ water systems . The electrochemistry and electrokinetics
of dispersed systems have been a subject of considerable
confusion and controversy '. The significance of the zeta
potential as a quantitative stability criterion has often been
overestimated and its computation from the electrokinetic
data has been oversimplified^ 4 ' ' 37 '.
Considerable difference of opinion has prevailed in the
interpretation of electrochemical-potential measurements on
clay suspensions and on clay membranes or shales.
Electrokinetics and electrochemistry of dispersed
systems are difficult subjects which do not readily lend
themselves to elementary treatment. For clay surfaces the
charge density is independent of the electrolyte concentration.
-36-
The effect of cationic valency is very strong, and divalent
ions could reduce the charge to zero at low concentrations
while trivalent and tetravalent ions could cause a reversal
Both in natural waters and in industry, deliberately
added ionic surface active substances may adsorb on particles
and thus charge thenr '.
2.6.7 THE ELECTROKINETICS OF COAL SUSPENSIONS
Information regarding the detailed electrokinetic studies
on coal is still lacking and research on the subject is at/ f-o \
an early stage of development '.
Baker and Miller ' indicated the importance of zetaforpotential control in coal preparation.plants such as thickening,
clarification and froth flo tation. It has been observed in
filtration rate studiesof coal slurries that the flocculant
efficiency improves as the zeta potential approaches zero.
Hydrogen and hydroxyl ions appear to be responsible for
the charge on the surface of coal. These ions participate in
the charge distribution which leads to equilibrium at the
coal-water interface*1 '. By determining the electrophoretic
mobilities of the fine coal particles as a function of pH, the
iso-electric points of various coals were found to correspond
to the pH at which the mobility is zero '.
Brown^ has suggested that the mechanism by which the
zeta potential of coal varies with increasing acidity of the
solution. Hydrogen ions are preferrentially adsorbed in the
-37-
electrical double layer on the surfaces of coal and this
results in the lowering of the negative surface charge of
coal. With subsequent addition of hydrochloric acid the
negative charge on the surface is reduced to zero and the
iso-electric point is reached. Any further addition of hydro
chloric acid makes the surface charge positive. In alkaline
solutions, hydroxyl ions are adsorbed in the diffuse part
of the electrical double layer at the coal-water interface.
Consequently the magnitude of the negative zeta potential
is increased./ /-p \
Campbell and Sunv ' found that the iso-electric point
of anthracites occured in acid solution between the pH 2.5
and 5.0. These authors also found that durains and fusains
in anthracite yielded much higher iso-electric points than
vitrains in anthracite or whole coals in general. In their
opinion this shift is undoubtedly an effect of the higher
mineral content in the durains and fusains and the zeta potential
variation with pH for whole coals is a result of the combined
effects of the various lithotypes.
2.7 FLOCCULATIQN
The tendency of the particulate phase of colloidal
dispersions to aggregate is an important physical property
which finds practical application in solid-liquid separation(72) processes . The essential steps in the flocculation of
suspensions are:
-38-
(a) Destabilization of the particles by the
elimination of any repulsion between them.
(b) Collisions of destabilized particles to form
aggregates or floes.
Flocculants are added to the pulp prior to thickening
with the objective of increasing the settling rate of the
pulp solids, hence increasing the thickener capacity and(73) . decreasing the overflow density v '. Flocculant additions
are beneficial where the pulps contain appreciable quantities
of finely divided clays which will not otherwise settle.
Under these conditions the addition of flocculants may be
economically justified by the improved operating conditions
which may result from the circulation of a low solid content
overflow and by the avoidance of stream pollution.
These benefits have been discussed in detail by(74) (75) Dahlstrom v ; and Matoney v ' .
The two main problems associated with the use of
flocculants in washery circuits are the selection of effective
and economical flocculants from the wide range of reagents
available and the prediction from laboratory experiments of
the quantity of flocculant required for plant operation.
A possible treatment is selective flocculation by means of
which one component can be caused to aggregate and thus become
more readily separable. According to the accepted theory of
colloid stability small particles are attracted to one another
by van der Waals forces and tend to aggregate unless they are
kept apart by repulsive forces arising from the presence of
the electrical double layer^ 73 '.
-39-
Coagulation and flocculation processes can and do occur
simultaneously or with some degree of overlapping. They
are distinguished by their mechanisms of destabilization,
the types of chemicals used for their initiation and the
sizes of particles developed.
Coagulation is defined as the conversion of colloidal
and dispersed particles into small visible floes upon the
addition of a simple electrolyte. Increasing the concentration
of the electrolyte compresses the electrical double layer
surrounding each suspended particle and decreases the
magnitude of the repulsive interactions between particles
thereby destabilizing the particles.
Flocculation is the further agglomeration by an organic
polyelectrolyte. Polyelectrolyte flocculants are linear or
branched organic polymers. They have high molecular weights
and are water soluble.
Certain insoluble particulate materials which are
designated as coagulant or flocculant aids are often added
to suspensions to enhance solid-liquid separation.
Hydrodynamic aspects of flocculation have been discussed/ ~j~j ) ( 3 8 by Spielman '. Gregory ' has also reviewed the flocculation
by inorganic salts and the effects of polymers on colloid
stability. There are many cases where colloid stability can
be significantly reduced by adsorbed non-ionic molecules.
This is known as sensitization and is concerned with a reduced
surface charge. Sontheimer^ ', has discussed flocculation/ og \
in water treatment. O'Melia v ' has reviewed the coagulation
processes in waste-water treatment.
-40-
The role of surface silanol groups in the flocculation
of silica suspension by polyacrylamide has been carried out
Griot and Kitchener^ '. Flocculation by water-soluble
polymers has been reviewed by Kitchener '. Electrokinetic,
adsorption and subsidence studies on quartz dispersion in the
presence of a commercial synthetic polyacrylamide type( 81 ) flocculant have been reported by Healy '.
( 82 Linke and Booth ' have reviewed the physic'o -t chemical
aspect of flocculation by polymers. This involved a broad
general study of the physical chemistry of mineral-polymer
systems and the application of better polymeric flocculants
and dispersants for the mining industry./ Q O \
Dixon et al v ' have investigated the application of
cationic polymers.
The characteristics of flocculation of mineral
suspensions by polymers have been reviewed by Slater and
Kitchener . In many coal cleaning operations it is usual
to add flocculants to the coal concentrates prior to filtration
to increase the filtration rate ' .
The effect of a number of variables on the coagulation
of dilute clay suspensions with aluminium and iron coagulants/ Ofi \
was investigated by Packham . The variables included the
nature and concentration of clay, pH and the presence of
different ions.
A quantitative theory was presented which described the
kinetics of coagulation of colloidal systems containing more( 87 ) than one dispersed species^ '. Using the linear Debye
-41-
Huckel approximation for low surface potentials a general
expression has been derived to describe the potential energy
of interaction between dissimilar spherical colloidal
particles.
Studies on the mechanism and the rate of coagulation
of positive silver iodide sols by anionic surface active/ Q O \
agents have been investigated v '. The electrophoretic
behaviour of positive silver iodide sols in the presence of
anionic surface active agents has been studied by Ottewill
and Watanabe* ' .
( 37 ) Kuz'kin and Nebera have reviewed extensively theused
synthetic flocculants.in dewatering processes.
Akers has reviewed the destabilization of suspensions
by coagulation and flocculation.
2.7.1 THE APPLICATION OF ZETA-POTENTIAL DATA TO
FLOCCULATION STUDIES
Flocculation of mineral suspensions by polymeric
reagents is considered to result from a bridging mechanism( 81 82 91 ^' ' ' in which the effect of the electrical double layer
interactions is minor. The study of the bridging mechanism
is not readily amenable to investigation by electrolcinetic
techniques. The absorption of charged polymeric species to
charged mineral surfaces will produce changes in the zeta potential^ 10 ).
-42-
/ o-i \ , ( Q9 \Healyv ; andKuz'kinet al v ' have applied the zeta
potential measurements to study the adsorption of polymer
flocculants to minerals such as quartz, microlite calcite
I R1 1and fluorspar. Healy v ' considered that although the
adsorption of a partly hydrolyzed polyacrylamide reduced the
zeta potential of quartz, this reduction of zeta potential
was subsidiary to the bridging mechanism in causing aggregation
(92) and flocculation. Kuz'kin et a.1 ' in the study of the
relationships between the zeta potential, polymer adsorption
and flocculation showed that the adsorption and the bridging
mechanism were influenced by the surface charge and the charge
on the polymer chain.
Matheson and Mackenzie^ 85 ^ , Kuz f Kin et al^ 92 ' and Slater^ 3 '
have shown that polymer flocculation of negatively charged
minerals by anionic polymers can be activated by the presence
of divalent metal cations.I Q O \
Dixon et al have studied the effect of cationic
polymer adsorption on the stability of silica and concluded
that low-molecular weight cationic polymers can cause
coagulation of silica, which brings the particles sufficiently
close together for short-range hydro gen- bond ing forces to
promote bridging and flocculation. They suggested that highly
hydrated oxides of iron and aluminium may function as flocculants
for silica in the same manner as the low-molecular weight
cationic polymers.
(94) Black et al ' have investigated the effect of cationic
polymer adsorption on the stability and electrophoretic
-43-
mobility of kaolinite and montmorrilonite suspensions.
Their results demonstrate a close relationships between zero
zeta potential and minimum residual turbidity and also
provide electrokinetic evidence for the restabilization
which takes place when the particle surface becomes saturated
with polymer molecules./ 37)
Kuz'kin et al ' have studied the effects of weakly
anionic polymers on both zeta potential and flocculation
of silica and showed that the maximum degree of flocculation
occured at conditions of low zeta potential. Whether there
is any direct relationship between the zeta potential
reduction produced on negative surfaces by anionic polymer
adsorption and the flocculation produced by adsorption remains
uncertain.
2.7.2 THE APPLICATION OF ZETA-POTENTIAL STUDIES TO COAGULATION
OF MINERAL SUSPENSIONS
The coagulation of mineral suspensions by simple
electrolytes is more suited to the quantitative use of the
zeta potential data than most other mineral processing
operations. The Derjaguin-Landau '- Vervey-Overbeek^ '
(DLVO) theory requires for its application the numerical
values of the Hamaker constants and of the Stern potential.
Unfortunately direct measurement of the Stern potential is not
possible for most systems.
-44-
Many of the applications of the DLVO theory to the
mineral processing coagulation systems have been concerned
with suspensions of silver iodide, silica and polystyrene.
The particle sizes were very small and the suspensions acted
as Rayleigh scatterers which facilitated measurement of
turbidity.
One of the disadvantages of this approach has been that
these suspensions exhibit surfaces which may not be similar to
those of the strongly crystalline comparatively coarse
particles in mineral processing operations.
A number of investigators including Mackenzie^ ' have
developed models for coagulation of suspensions using
hydrolysable metal cations which involve a combination of
coagulation and flocculation mechanisms. These models have
been developed because some of the coagulation data for
regatively charged suspensions in the presence of hydrolysable
cations cannot be interpreted in the terms of the DLVO theory.
Several theories have been proposed to explain the
coagulating behaviour of hydrolysable cations. This included
heterocoagulation of positively charged metal hydroxide
precipitate and negatively charged suspension particles, and
flocculation via polymer bridges of the solution by polymeric/ QQ Q/-J \
uncharged hydrolysis products^ » y^J m It i s not possible to
determine which of these mechanisms control the coagulation
and flocculation of suspensions by hydrolysable metal ions.
The apparent lack of correlation between zeta potential data
and coagulation data for these systems would suggest that
-45-
electrokinetic techniques are of little value in studying
coagulation. However it is this lack of correlation which
has led many workers^ ^ to search for other coagulation
mechanisms, thereby justifying the initial application of
zeta potential measurements.
These measurements have also aided in the determination
of species which adsorb at mineral-water interface. Hence
despite the failure of the DLVO theory for certain cases of
combined coagulation-flocculation processes, the value of
zeta potential measurements in understanding these processes is considerable (4 ' 10) .
2.7.3 ZETA POTENTIAL STUDIES ON THE ADSORPTION OF METAL
CATIONS AT THE MINERAL-WATER INTERFACE
The adsorption of metal cations at the surface of mineral
particles has been the subject of extensive electrokinetic
(97 ) studies by a number of workers including Healey et al ,Mackenzie^ 98 ), Mackenzie and 0'Brien^ 99 ^ and Hall^ 100 ^.
Others including Clark and Cooke ' have studied the action
of metal cations as flotation activators for quartz in the
presence of anionic collectors. Matijevic and co-workers
' ' have studied the action of metal cations as
coagulants for non-mineral sols such as colloidal silica.
They discussed their results in terms of electrophoretic
mobilities.
The results of these investigations demonstrate that
the metal hydroxy cation species are far more effective than
-46-
the simple metal ion in causing reversal of the zeta potential,
coagulation of oppositely charged suspension and flotation
activation.
The adsorption of metal cations to mineral surfaces is
a phenomenon which while amenable to zeta potential measurements,
must be studied by other complementary techniques such as
adsorption studies or flotation if meaningful interpretations
are to be made of the zeta potential data^ '. However it is
partly as a result of zeta potential measurements that this
phenomenon has been capable of physico-chemical interpretation.
2.7.4 THE APPLICATION OF ZETA POTENTIAL DATA TO THE STUDY
OF SELECTIVE AGGLOMERATION PROCESSES
Selective - agglomeration concentration processes are
those in which selective agglomeration of a particular
mineral followed by the separation of the agglomerates from
the dispersed minerals. This method is used to effect thedesired
concentration of the mineral. The processes vary widely inA
their technology and include operations such as "piggy-back"
flotation, emulsion flotation and selective flotation^ .
One aspect which is common to these processes is that
it involves the concentration of extremely fine-sized mineral
particles which are too fine to be concentrated by other
processes such as flotation.
Shergold and Mellgren^ ' used electrokinetic data to
study the mineral-water interface reactions involved in
-47-
emulsion flotation and established a relationship between
the point of zero charge of the mineral and flotation
recovery.
Yarrar and Kitchener^ ' have made extensive use of
zeta potential measurements in their analysis of the selective
flocculation process and have shown that for synthetic mixtures,
a knowledge of the appropriate zeta potential, and the effect
of pH on these potentials could provide a basis for predicting
the conditions for separation.
Sun and co-workers ' ' have studied the electrokinetic
properties of anthracite and bituminous coal. They postulated
that the coal surface hydrates and then undergoespH-controlled
dissociation to establish a charged surface in the same
manner as the oxide minerals '. The authors pointed
out that, in view of the heterogeneity of the coal surface it
is impossible to be certain how much the electrokinetic data
reflect the properties of the coal or mineral matter surface.
2 .8 CONCLUSION
In the past the mineral industry has been seriously
hindered by the awkward colloidal minerals and where water and
space were readily available, the slimes were dumped into
rivers and settling lagoons. If the concentrates or clay
products had to be dried the operation had to be carried out
at a reasonable cost. The situation is now changing rapidly
and a number of factors such as falling grades, environmental
-48-
protection and rising fuel cost will have to be taken into
consideration.
It is widely recognized that whatever form of machinery
is selected for the solid-liquid separation process, the
operation can be greatly facilitated by controlling the
flocculation of the particles in the colloidal range.
In the first half of this century mineral technology
was successfully carried forward by ad hoc inventions. There
is now a need for continuing research effort into the science
of colloidal minerals so that improved technologies could be
rationally developed to treat smaller particles
in environmentally acceptable terms.
The surface chemistry of mineral grains in water should be
understandable in terms of the dissolution and surface
ionization of idealized compounds. In practice due allowance
must be made for non-equilibrium conditions and time effects,
the effect of impurity elements, degradative changes of the
mineral and reactions with substances deliberately present(19) in the aqueous medium v '. These chemical factors can generally
be manipulated to permit dispersion, separations, coagulation,
flocculation and flotation.
For a thorough description of the progress of aggregation
it would ideally be desirable to have a record of the initial
particle size distribution and composition as a function of(2 1927 37 ) time 1 ' ' ' '. None of the classical techniques for
measuring coagulation and flocculation such as turbidity,
particle counting and light scattering offers a quantitative
-49-
measure of a concentrated slurry containing a wide range of
particle size. Consequently experimenters are obliged to
devise empirical test methods to suit their particular
objectives without being able to extract fundamental data
from the results (2 ' 17 ' 19 ).
A number of complications may arise because mineral
slurries commonly contain particles of different sizes and
shape and also mineral species of different chemical
nature. Hence the effects of heterogeneity can be anticipated
in addition to the distinct perikinetic and orthokinetic
flocculation mechanisms.
Before the advent of synthetic polymeric flocculants
waste mineral slimes were dumped in a slimes dam usually with
an addition of lime to precipitate out heavy metal salts and
to encourage coagulation and flocculation. Inorganic coagulants
such as alum and ferric salts were never extensively applied
for mineral slimes because of their lack of strength to
bond relatively large particles unless used at very large
dosages.
The first use of organic flocculants appears to have
been the use of starch together with lime for the clarification
of colliery effluent containing coal particles with clay from( T 9 ^7
the shale v ' ; . Regrettably it is still not possible to
select the best flocculant for a particular ore entirely on/2 17 ig 37 \
physical principles^ ' ' ' '. The simple idea of choosing
a polyelectrolyte of opposite sign to that of the solids rarely
gives the best results, either in terms of floe size or reagent
-50-
cost, though more or less effective flocculation can always
be guaranteed on this basis. Knowledge of the zeta potential
of the particles and its dependence on the ions in the medium
is desirable together with possible interaction of these ions
with the flocculant.
As most minerals in waters carry a moderate negative
zeta potential the most useful flocculants are the very high
molecular weight polyacrylamides incorporating a minor
proportion of carboxyl groups to obtain expansion. It is
advantageous to reduce the zeta potential of the particles
considerably before or after the addition of the flocculants
either with divalent or hydrolyzing cations or polyamine(2 19 3V 9O ) type of primary coagulants ' ' ' '. In most cases there
will be many possible answers to a given flocculation problem.
The best will not necessarily be the cheapest flocculant that
works or the one which gives the largest floes, the clearest
supernatant or the fastest filtration. Every situation should
be optimized on its merits depending on the relative importance
of the various factors.
Flotation is presently widely used to recover the
fine coal particles. The waste slurries contain mainly shale
particles. Much of the water should be recycled but if the
solids build up beyond fifty grams per litre flotation grade
suffers because of slime coating. At one time starch products
were used to aid the solid-liquid separation but they have
been largely displaced by polyacrylamides. In addition to
the water problem there is need to improve the thickening and
-51-
filtration of the suspended solids so as to get these wastes
into sufficiently solid form for transport and dumping. The
plant needs control to ensure that free polymer does not get
back to the flotation unit where it can act as a depressant.
In contrast to relatively amenable shale suspensions there
are certain clay slurries which present much greater difficulties (19,26)
In current mineral processing research there is the need
to develop new technologies for recovering valuable minerals
from slimes since these slimes rejected from the conventional
flotation plants often contain in substantial
proportions of the valuable minerals.
Several distinctly different principles have been proposed
for effecting mineral separation in the colloidal size range
and many combinations of processes are possible ' .
The physico-chemical methods of separating mineral
particles are economically attractive down to a tenth of a
micron size since the amount of the chemical reagent required
to modify the surface chemistry is still small compared with
the amount of the reagents needed to dissolve the valuable
constituents of the ore and to carry out a purely chemical
separation.
It can be concluded that both flocculation and selective
flocculation have proved practicable and adaptable to a variety
of problems including clarification of colliery waste-water.
It is not too costly but reliable economic estimates can be
made only for specific cases after thorough bench and pilot- plant testing(2 ' 7 ' 19 ' 37) .
-52-
PHYSICO-CHEMICAL PROPERTIES OF COLLIERY WASTE-WATER
CHAPTER 3
-53-
3.1 INTRODUCTION
The colliery waste-water was obtained from the South
Celynen Coal Mines atNewbridge, Gwent in South Wales. It
was taken at the point before the colliery waste-water was
sent to the flocculation unit. The colour of the colliery
waste-water is light to dark brown, containing black
and brownish-black particles.
Coal is a combustible solid usually stratified which
originates from the accumulation and burial of partially
decomposed vegetation in previous geologic ages. There is a
wide range in the composition and the physical and chemical
properties of different kinds of coal.
Coal lumps are black or brownish-black in colour. The
colour, lustre, texture and fracture vary with type, rank
and grade. The composition of coal is chiefly carbon, hydrogen,
and oxygen with minor amounts of nitrogen and sulphur together with
varying amounts of moisture and mineral impurities. The
composition depends on the degree of alteration of the original
plant ingredients, on their subsequent upgrading in rank and
pressure and temperature effects in the earth and on mineral
impurities deposited in the original bog. It is thought that
the predominant organic components have resulted from the
formation and condensation of polynuclear carboxylic and
heterocyclic ring compounds containing carbon, hydrogen,
oxygen, nitrogen and sulphur^ '.
The mineral constituents in coal may be the residue of
mineral substances present in the original plants, detrital
-54-
minerals deposited at the time of formation, or secondary
minerals crystallized from waters percolating through the
coal seams. The most common detrital material is clay and
it may be associated with quartz, feldspar r muscovite,are
rutile and topaz. The secondary minerals generally kaolinite,
calcite and pyrite. Traces of other elements such as vanadium,
titanium, manganese and calcium have been found in coal ash
and are thought to represent the minerals surviving from
the plant material (26 ' 67 ' 109) .
Clays are usually composed of o.ne or more clay-minerals.
These minerals include hydrous silicates of aluminium, iron
or manganese with or without other rock and mineral particles.
Clay may originate through several processes such as hydrolysis
and hydration of a silicate, solution of a limestone or other
soluble rock which contains relatively insoluble clay impurities
that are left behind^ ' . Clays are characterised by fine
particles of colloidal size and by wide variations in physical
and thermal properties and in mineral and chemical composition.
Clay is used by geologists as a size term which refers
to sediments or sedimentary rock particles of mechanical
deposition. Soil scientists also define clay as disperse
systems of colloidal products of weathering in which secondary
mineral particles of smaller dimensions predominate. Ceramists
usually colour their definition by emphasizing plasticity and
its alumino-silicate content. Clay minerals are considered
as degradation products of silicates which may be built up
from hydrates of silica and alumina^ 10 '. Clay deposits
-55-
usually contain more or less non-clay minerals as impurities.
These may be beneficial and critically necessary to give clay
its unique and specially desired properties.
The mineralogy of clay minerals rested on a poorly
organized and insecure foundation until satisfactory
apparatus and techniques, especially x-ray spectroscopy were
developed to study the fine mineral particles. Crystalline
clay minerals are identified and classified primarily on the
basis of crystal structure and the amount and locations of
deficit or excess charge with respect to the basic lattice
(26,109,110)
Various techniques are used to study crystalline clay
minerals including electron micrographs, transmission electron
micrographs, scanning electron microscopy, x-ray or electron
power di:
110,111)
power diffraction and differential thermal analysis ' '
chemicallyThe clays of different groups are^similar but they show
vastly different mineralogical, physical, thermal and
technological properties^ ' '. Chemical analysis alone
may have limited values in revealing the clay* s identity or
usefulness.
3.2 THE PHYSICAL PROPERTIES OF THE COLLIERY WASTE-WATER
The densities of the raw waste-water, the suspension
obtained after twelve hours of sedimentation and the filtrate
obtained after filtration of the suspension were determined.
-56-
The weight of the sediment in the colliery waste-water was
also determined.
Samples were allowed to settle for twelve hours to obtain
a sediment and a suspension. The suspension was decanted,
weighed .and its volume measured. This suspension was then
filtered using Millipore membrane filters (porosity of 0.22yum)
to determine the amount of solid fines in suspension. Twelve
experiments were carried out.
The density at ambient temperature of the raw colliery
3 3waste-water was found to be between 972.6 kg/m and 1008 kg/m ;
the density of suspension obtained after twelve hours of3 3sedimentation 950.1 kg/m and 989.1 kg/m ; and the density of
the filtrate obtained after the filtration of the suspension
940.4 kg/m3 and 993.4 kg/m3 .
The amount of sediment obtained after twelve hours ofand
settling^the decantation of suspension above the sediment was
determined to be between 3.1% and 3.6%.
Detailed results will be found in Appendix Al .
-57-
RAW SAMPLE
-(COLLIERY WASTE-WATER)
12 HOURS OF SEDIMENTATION
FINES IN
SUSPENSION
FILTRATE
SUSPENSION
SEDIMENT
,DECANTATION
SUSPENSION
FILTRATION
Fig. 3.1 DETERMINATION OF THE DENSITIES OF RAW COLLIERY
WASTE-WATER, SUSPENSION, FILTRATE AND THE
AMOUNTS OF SOLIDS IN THE SEDIMENT AND
SUSPENSION.
-58-
3.3. THE PARTICLE SIZE MEASUREMENT
Characterisation of the particle size distribution is
one of the most basic physical properties common to finely
divided substances
Particle size distribution covers the quantitative
determination of the various substances in the sample down
to the fine grain size as reported in BS.1377:1975,
paragraph 2.7.
Many authors including Tiller ' Svarovsky ' Coulson
and Richardson^ 15 ), Perry^ 16 ^, Allen^ 27 ^ and Irani et al^ 28 ^
have investigated and reviewed particle characterisation size
and distribution which include the methods of optical
microscopy, scanning electron-microscopy and the electrical
sensing zone method (Coulter Counter).
3.3.1 OPTICAL MICROSCOPY IN PARTICLE SIZE MEASUREMENT
Microscopy is the most direct method for particle size
distribution measurement. Its range of application is very
large but practical limitations and availability of more
expedient techniques make microscopy a less desirable tool
in certain size ranges. Microscopy is an absolute method
of particle size analysis since it is the only method in which
the individual particles are observed and measured. It also
permits the examination of shape.
The Greenough Binocular Stereoscopic microscope-Olympus
Model X and the vickers M14/2 Patent No. 877813 microscopes
-59-
were used to observe the particles.
The raw colliery waste-water was observed to contain
fines (fine solids) of various sizes and their shapes were
irregular. They were observed to be light to dark-brown
and greyish-black and some of the particles were highly
reflecting. In some cases, some of the light reflecting
particles were enclosed in a dark brown or greyish matrix.
3.3.2 SCANNING ELECTRON MICROSCOPY (S.E.M.) IN PARTICLE
SIZE MEASUREMENT
In the scanning electron microscope a fine beam of
electrons of medium energy is caused to scan across the
sample in a series of parallel tracks. These electrons
interact with the sample, producing secondary electron emission
(S.E.E), back-scattered electrons (B.S.E.), light or cathodo-
luminescence and x-rays.
Samples as large as 25 mm x 25 mm can be accomodated
and parts viewed at magnifications from 20 to 100,000 at10 m
resolutions of smaller than 200 . in special cases. The
depth of the focus is nearly three hundred times that of the
optical microscope. The Scanning electron microscope -
Stereoscan SEM TL 1153-OM was used to determine the shape of
the particles obtained after six hours of sedimentation.
Three different layers were obtained after the six hours of
sedimentation namely:- the sediment; the clayey solution
above the sediment and the suspension above the clayey solution.
-60-
This suspension was then centrifuged using Heraeus Christ
GmBH Osterode/Harz Picolo centrifuge No. 38836 and filtered
by using the Millipore filters (0.22/um porosity). The
sediment and the clayey solution were evaporated at 50 C
followed by drying in vacuo at 50°C and finally over
phosphorus pentoxide (P^^S^ ^"n a desiccator '
The results indicated that the fines were of irregular
shape, some plate or tube-like and of a diversity of colour
and sizes.
Photographs were taken and can be seen in AppendixA2.
See fig. 3.2 for the sedimentation process after six hours.
3.3.3 THE ELECTRICAL SENSING ZONE METHOD OF PARTICLE SIZE
DISTRIBUTION - THE COULTER PRINCIPLE -
The Coulter Counter technique is a method of determining
the number and size of particles suspended in an electrolyte
by causing these particles to pass through a small orifice
on either side of which is immersed an electrode. The charges
in resistance as particles pass through the orifice generate
voltage pulses whose amplitudes are proportional to the volume
of the particles.
The Coulter counter model TA can be used to determine
the particle size distribution in the size range of 0.5 to
400/juaxi of the equivalent spherical diameter. The particle
size analysis is available in both volume and weight modes:
-61-
(a) frequency distribution percentage,
(b) cumulative distribution percentage,
(c) relative volume frequency distribution,
(d) cumulative relative volume distribution.
The colliery fines were allowed to settle under gravity
(gravity sedimentation) for six hours obtaining a sediment,
a clayey solution above the sediment and the suspension.
The suspension was further fractionated by centrifuging and
filtration as carried out in the preparation of the sample
for the scanning electron microscopy. These various fractions
obtained were then examined using the Coulter Counter Model TA.
In general the particle size distribution was in the
range of 3.5 to 92.0yum for the coarsest fraction and 1.24 to
31.5yum for the finest fraction. Detailed results have been
tabulated in Appendix A3. These results were graphed in the
particle size charts in BS 1377:1975. From these results
it was concluded that the fines contained primarily clay, fine,
medium and coarse silt and fine sand. See fig. 3.2 for the
sedimentation process after six hours.
3.4 THE CHEMICAL ANALYSIS OF THE COLLIERY WASTE-WATER FINES
The elemental analysis was carried out in the first
instance by the application of the Energy Dispersive X-ray
Microanalysis using the equipment - Link Systems 860.
Energy dispersion is not well suited to quantitative
analysis of low concentrations because the shift in the pulse
-62-
amplitude with counting rate depends on the total counting
rate rather than that of the individual element. Thus, there
may be an appreciable (but unknown) shift in the amplitude
distribution of a low concentration element compared to the
standard for that element. This, therefore makes the value
of the low concentration element subject to relatively large
errors.
The raw colliery waste-water was evaporated at 50 C
followed by drying in vacuo at 50°C and finally over phosphorus
pentoxide (P^O,.) in a desiccator. The solid obtained was
then ashed, and subjected to chemical analysis according to
the British Standards - B.S. 1016 part 14. The procedures
given in BS1016 part 14 could not be applied to analyze the
oxides of magnesium and iron. The preferred methods in
industry for the analysis of the oxides of magnesium and
sulphur are the atomic absorption spectrophotometry and
Eschka's method respectively.
Microanalytical techniques were applied in the analysis
of carbon and other elements which could not be analyzed by
the Energy Dispersive X-ray equipment.
The total carbon was found to be 9.2%
Detailed results can be found in Appendix A4.
-63-
3.5 MINERALOGICAL ANALYSIS OF FINES IN COLLIERY WASTE-WATER
X-ray powder crystallography was applied to the same
samples used for particle size distribution (Coulter-counter)
and the lattice spacing calculated from the Bragg equation.
These results were compared with the ASTM Index and the
minerals tentatively identified are in Appendix A5.
The table X-ray Generator PW-1720 ,and the camera XDC-700
Guinier-Haag were used to carry out the mineral analysis.
Aluminium silicates were found to predominate.
The literature survey has indicated that clay minerals
are essentially hydrous aluminium silicates, with magnesium
or iron substituting wholly or partly for the aluminium in
some minerals and with alkaline earth present as essential
constituents. Some clays are composed of a single clay mineral
but most are mixtures. In addition to the clay minerals some
contain varying amounts of the so-called non-clay minerals of
which quartz, calcite, feldspar and pyrite are important
examples. Also many clay minerals contain organic matter and
water soluble salts.
From the Inorganic Index to the Powder Diffraction File
(1969) compiJ ed by the Joint Committee on Powder Diffraction
Standards, the lattice or d-spacings calculated for the
reflections obtained from the X-ray analysis corresponded with
those of basic aluminium silicate and aluminium silicate
hydroxide. These compounds obtained from the X-ray analysis
conform to the elemental analysis (chemical analysis) and also
to the particle size distribution chart - BS 1377:1975 fig.10,
-64-
which gives clays to be present. Clays are basically
aluminium silicates.
Results of the mineralogical analysis can be found in
Appendix A5. See fig. 3.2 for the preparation of the samples for
X-ray crystallography.
3.6 THERMAL ANALYSIS OF THE CLAY MINERALS
The methods of thermal analysis have provided an
invaluable aid for the determination of the composition of
some native or artificial compounds and minerals. They are
based on the chemical processes and physical phenomena which
occur in a solid when it is heated*1 '.
The samples were prepared in the same way as that for
the scanning electron microscopy and the size distribution
by the Coulter counter equipment.
These samples were analysed using the differential
scanning calorimeter - Model DSC-2 and thermogravimetric
system Model TGS-2.
Two thermal peaks were obtained in each case the first
occuring around 100 C and the second around 450°C to 550°C.
The first peak corresponds to the loss of water and the
second is probably due to the decomposition of organic matter.
The presence of the organic portion present prevented any
detailed interpretation of inorganic constituents present in
the colliery fines. Hence unless the organic fraction can be
physically separated from the rest, identification would not
-65-
be possible. Consequently attempts were made to separate
the coal-inorganic constituents by heavy liquid density
gradient fractionation.
3.7 HEAVY LIQUID DENSITY GRADIENT FRACTIONATIQN
The heavy liquid density gradient technique enables the
separation of a physical mixture of clay minerals provided
their densities do not overlap one another. The technique
is based on a column of heavy liquid (Clerici solution)
(113,114,115,116) in which the density decreases continuously
from the top to the bottom of the column. The individual
particles settle at their appropriate density levels to form
sharply defined mineral layers upon adding a mixture of
liberated minerals to such a column. Interstitial clay minerals,
and minerals with a continuous, overlapping density range
do not yield separate zones. They can only be fractionated
by taking samples from different portions in the zones. A
banked or staircase-shaped gradient may create artificial
zoning and facilitate isolation of samples.
There was no separation of the clay minerals-coal particles
in distinct zones and bands. All the samples introduced into
the mixture of thallium malonate and thallium formate (Clerici
Solution) which have been put in the density gradient column
remained together in the same zone. Thus this method could
not be applied to the separation of the colliery fines.
-66-
3.8 FRACTIONATION BY GRAVITY SETTLING (PIPETTE METHOD)
Owing to the failure with the heavy liquid density
gradient fractionation, gravity settling (sedimentation)
was examined to see if any fractionation occured.
Twenty samples were taken using the pipette method-
BS 1377:1975.
If separation had taken place on the basis of particle
size and weight then these samples should be different from
one another.
These twenty samples were subjected to particle size
distribution using the Coulter Counter Model TA and chemical
analysis using the Energy Dispersive X-ray equipment, X-ray
crystallography and thermal analysis.
The results were the same as the original sample
indicating that negligible separation had occured and that
the solid fines are very intimately mixed and therefore very
difficult to fractionate.
1
2
3
Fig. 3.2 Sedimentation after (6) six hours.
Sediment after six hours of settling (Al & A2)
Clayey solution obtained after six hours of settling (Bl & B2)
Suspension obtained after six hours of settling:-
Cl and C2:- Solid fines obtained after filtration usingMillipore membrane filters of 0.22yum porosity
Dl and D2 Solid fines obtained after centrifuging.
-67-
DESCRIPTION OF MICROELECTROPHORETIC APPARATUS
CHAPTER 4
-68-
4.1 INTRODUCTION
Various experimental techniques have been developed for
studying the electrokinetic effects by many authors including
Tiller^, Hunter^ 4 ^, Mackenzie^ 10 ), Overbeek (1 ' and Ross^ °'.
These experimental techniques include; electrophoresis
(micro-electrophoresis), electro-osmosis, streaming and
sedimentation potential. Having considered these techniques
the method of microelectrophoresis was applied to the
study of the electrokinetic effects on the colliery waste-
water.
(49) Shaw ' has reviewed the experimental techniques of
(4) electrophoresis and its practical applications. Hunter '
has also reviewed the measurement of electrokinetic parameters.
Electrophoresis is the most common procedure for the
determination of zeta potential and several techniques have
been developed for the application to different types of
material 1 ' ' ' ' . Micro-electrophoretic procedure is the
movement of individual particles in the colloidal size range
under the influence of an electrical field. This movement
of the particles is followed directly in an ultramicroscope
assembly or dark-field microscope.
Only very dilute sols can be studied by the technique of
micro-electrophoresis. The particle concentration must be
so low as to induce only the slightest haziness in the solution,
since interparticle interference and multiple light scattering
may make the results invalid. Dissolved materials can also be
studied in this way if they are adsorbed on to carrier particles.
-69-
4.2 MICRO-ELECTROPHORESIS
Much of the pioneering work on micro-electrophoresis
(electrophoresis) was done without stabilizing media. Picton
et al^ ' appear to have originated the method in 1892,
but it was not developed until 1937 when Tiselius
described the apparatus and methodology.
Until quite recently almost all the work on electrophoresis
was applied in the separation of proteins and blood cells.
Thus electrophoresis was mainly used in biochemistry and
clinical work.
Bull carried out experimental work in which he made
a critical comparison of electrophoresis, electro-osmosis and
streaming potential in which he modified the electrophoretic cell
The zeta potential is rather difficult to measure
experimentally and many authors ( l ' 2 ' 4 ' 7 ' 10 ' 40 ' 128j129 ) have
measured the electrophoretic mobility of the particles and
hence the calculation of the value of the zeta-potential.
Electrophoretic mobility measurements were performed on
kaolinite by Street and Buchanan^ '. Bangham et al^ '
have designed and constructed an apparatus for micro-
electrophoresis of small particles. An improved version was
designed by Smith ' and marketed by Rank Brothers (Bottisham,
Cambridge, England). Black et al^ 1 7 ^ investigated the
electrophoretic mobility of colloidal particles by applying
the method of micro-electrophoresis.
Deju et al ' have constructed a modified electrophoresis
apparatus for the determination of zero point of charge for
-70-
quartz. The electrophoretic mobilities of quartz, beryl
and microline were also investigated to determine the zero
point of charge.
The electrophoretic velocity of colloidal particles
can be determined by the direct observation of a colloidal
sol in a closed capillary tube.
4.2.1 MICRO-ELECTROPHORETIC CELL DESIGN
Many workers including Mattson^ ', Bull^ , Smith
et al^ 119 ^ and Rutgers et al^ 1 ' have reviewed the various
cells which have been used in the study of micro-electrophoresis
The cells are easily cleaned, rugged and reliable.
The prominent features of the various micro-electrophoretic
cells have been described by Shaw presenting line drawings
of the designs by Mattson ' and Alexander et al^ .
A micro-electrophoresis cell consists simply of an
observation tube of either circular or rectangular cross-
section with an electrode at each end and with inlet and outlet
taps attached. Shaw^ ' .observed that the micro-electro
phoretic measurements are complicated by the simultaneous
occurence of electro-osmosis near the walls of the cell. The
initial surface of the cell are generally charged, and the
applied electrical field causes an electrophoretic migration
as well as electro-osmosis flow of liquid near to the tube
walls together with a compensating return flow of a liquid
with maximum velocity at the centre of the tube since the cell
-71-
is usually closed. This results in a parabolic distribution
of liquid speeds with depth and the true electrophoretic velocity
is observed only at the stationary levels in the cell where
the electro-osmosis flow and return flow of liquid cancel.
Mattson^ ' has constructed a cylindrical cell for use
in the study of electrophoresis. The cell was in a series of
investigations dealing with the iso-electric precipitation of
a number of complex precipitates such as silicates, phosphates
and proteinates of aluminium and iron.
Smith and Lisse ' constructed an electrophoretic cell
for the microscopic observations of the velocities of particles.
An apparatus was designed for quantitative electrophoretic
work using different cells by Alexander et al ' in the
determination of electrophoretic mobility. Rutgers et al^ '
also constructed an electrophoretic cell.
Electrophoretic mobility measurements were carried oigt
by Street and Buchanan by constructing the electrophoretic
cell from a pyrex capillary with flat grounds.
(129} More recently Shergold et al ' have designed a
demountable electrophoretic cell for work on mineral particles.
The electrophoretic mobility of a suspension of Fransil - a
finely divided vitreous silica powder in distilled water
was determined. The cell design was based on a commercially
available spectrophotometer cell withopen ends.
-72-
4.2.2 OPTICAL SYSTEM OF MICRO-ELECTROPHORESIS
Shaw (40) , Hunter (4) , Smith et al (l26) and Shergold et
al (129) and many research workers have used dark-field
illumination in which the electrophoretic cell is illuminated
at right angles to the direction of observation.
The optical system of the microscope should consist of
a long working distance objective to permit focusing on any
level within the electrophoretic cell^ ' ' . The degree
of magnification should be high in order to minimize the
depth of focus and permit accurate location of the particles
at stationary levels.
The eyepiece is equipped with a graticule to enable
the distance travelled by each particle to be measured in a
given time' 4 ' 40 > 125 ' 126 >.
4.2.3 ELECTRICAL SYSTEM OF MICRO-ELECTROPHORESIS
A power supply which is stabilized against the mains
fluctuation should be applied to produce the electrical
field in the electrophoretic cell (4,40,119,125,127,129)_
The voltage rather than the current should be maintained
constant, if the effective length method for determining
the field strength is applied.
Electrodes are selected with the view of either eliminating
or reducing polarization at the electrode^ 4 ' 40 » 128 » 129 ) and
the contamination of the observation chamber with electrode
material.
-73-
4.3 A MODIFIED MICRO-ELECTROPHORETIC APPARATUS FOR
ELECTROKINETIC MEASUREMENTS OF THE COLLIERY WASTE-WATER
The phenomenon of micro-electrophoresis
has been studied for many years and a lot of work has been
carried out in designing an apparatus to improve upon the
measurements of mobility, zeta-potential and the point of
zero charge of minerals. Until presently most electrophoretic
experiments have involved cumbersome equipment, tedious
microscopic observation and the use of dark-field illumination.
The modified micro-electrophoretic apparatus which has
now been designed for the measurements of electrophoretic
mobility, particle charge, and zero point of charge and iso-
electric point of charge combines the simplicity of construction
with an improved method of measurement of velocity of the
particles and the reduction of the contamination of the cell.
The images of the particles were projected onto a television
screen and this eliminates the need for tedious measurement
of the velocity of the particles using the microscope
graticule. It utilizes the ultra-microscope principle of
direct illumination and the light source is placed directly
below the electrophoretic cell.
The general set-up can be seen in Figs. 4.1 and Fig. 4.2.
-74-
4.3.1 DESIGN AND CONSTRUCTION OF THE MICRQ-ELECTROPHORETIC CELL
The electrophoretic cell consists of two similar electrode
compartments and a perspex cell. The electrode compartments
were machined out of solid rectangular blocks of perspex.
The perspex cell was supplied by Hughes and Hughes (Romford,
Essex), and it is 1-mm standard spectrophotometer cell,
40-mm long and 10-mm wide with an open and closed end. The
perspex cell is then fitted into the two electrode compartments
by slots which have been machined onto one face of each
electrode compartment. The rectangular cell is preferred to
the cylindrical cell since it has gained more adherents
recently owing to the optical difficulties associated with
the cylindrical design.
The platinised wire which is used as an electrode is
then passed through a perspex tube (see Fig. 4.2) into the
electrode compartment and is held in position by perspex
glue.
The sample is then passed in and out of the electrophoretic
cell through holes in which have been drilled on top of the
electrode compartments into the cell. During filling of the
cell with the sample, air is allowed to escape through the
other hole drilled in the electrode compartment by opening
the exit valve.
When the cell is in use the electrophoretic cell and the
capillary tubes joining the cell and the reservoirs are
completely filled with the sample.
-75-
Pig. Photograph of the Assembly of the modified
micro-electrophoretic apparatus.
-76-
'k
\ 9 7
12
FRtDh THE MAINS ..
FIGURE.4.2. ASSEMBLY OF WE MODIFIED MICRO-ELECTROPHORESIS APFfcRATUS
-77-
1. TELEVISION SET FOR RECORDING
2. VIDEO-CASSETTE RECORDER
3. TELEVISION MONITOR
4. TELEVISION FOR MEASURING VELOCITY OF PARTICLES
5. RESERVOIR TANKS FOR SAMPLE
6. TELEVISION CAMERA
7. MICROSCOPE AND LAMP HOUSING
8. ELECTROPHORETIC CELL
9. COPPER SULPHATE SOLUTION-HEAT FILTER
10. LIGHT SOURCE
11. VOLTMETER
12. AMMETER
13. POWER UNIT-CONVERTER
14. REVERSING KEY
-78-
This assembly is easily clamped to the microscope stage
and demounted to allow cleaning to be carried out without
constraint.
Detailed design of the electrophoretic cell can be seen
in Fig. 4.3.
4.3.2 OPTICAL SYSTEM
The optical arrangement of the modified micro-electrophoretic
apparatus comprises these equipments:-
a) Metallux-2 Metallographic microscope-Ernst Leitz
GmBH D-6330 WETZLAR.
b) Levis-Leitz Wetzlar, Achromats NPL 10:x/0.20, with
free working distance of 14.2mm and focal length
of 25.0mm.
c) Television Camera-National Miniature CCTV System,
TV Camera WV-401.
d) Television Monitor - National WV-411.
e) Television Screen - Hitachi Solid State TU-201K
f) Video Recording Set-up
(i) Video recorder-SONY Serial No. 15616U-matic video cassette recorder - (VO-1810 U.K.)
(ii) Television Set-Sony Trinitron Colour T.V. Receiver Serial No. 525761
g) Light Source - Leitz Wild Heerbrugg and Ernst Leitz
Wetzlar GmBH. Wild Best Nr.319553, Leitz Best Nr.500253.
h) Heat filter - Copper Sulphate Solution - 25% by
weight (25gm in lOOcc)
-79-
FIGURE. 4.3 DESIGN OF THE MICRO-ELECTROPHORET! C CELL
ILt
2-50-iom-
3-0
ELECTRODE COMPARTMENT
"X.PUTINUM ELECTRODE
"* S-Q. 102mCF1.L
FIGURE *».3a. FRONT-VIEW OF THE MICRO-ELEC TROPHORETIC CELL
2-50. Mm
FIGURE. 4. 3b TOP-VIEW OF THE MICRO- ELECTROPH ORETIC CELL
r.,2-5.10m
0
3-0 . 1(T2
FIGURE. ^.3c SIDE-VIEW OF THE MICRO-ELECTROPHORETIC CELL
-80-
4.3.3 ELECTRICAL SYSTEM
The electrical arrangement of the micro-electrophoresis
apparatus comprises the following:-
a) Regulated Power Unit Model SRS 152 Serial No.
24357 - Solartron Laboratory Instruments Ltd.,
Thames Ditton, England.
b) Digital Multimeter Alpha 11 - Serial No. 3350.
c) Farnell Digital Multimeter - Model DM131/B
Serial No. 001465.
The regulated power unit converts the alternating
current (AC) from the mains to direct current (DC) which
can be used to perform electrophoresis.
The Digital Multimeter - Alpha 11 is used to measure the
current which passes through the electrophoretic cell and
this can measure current in the range IjuA to 1000mA.
The Farnell digital multimeter is also used to measure
the voltage across the electrophoretic cell to enable the
determination of the potential gradient.
4.4 ELECTROPHORETIC MOBILITY OF QUARTZ
The electrophoretic mobility of quartz, the zero point
of charge and the iso-electric point were determined using
the modified micro-electrophoretic apparatus which has been
described in paragraph 4.3 and fig. 4.2. This was carried
out to establish the validity of the modified micro-electro
phoretic apparatus which has been designed and constructed
-81-
for the study of the electrokinetic parameters of the
colliery waste-water. The results obtained agreed within
experimental error with the work published by Bhappa et al
There was a slight modification in the size of the
modified electrophoretic cell chamber which had to be reduced to_2
4.0 10 m owing to the low conductivity of the quartz
suspension as compared to the colliery waste-water. The
optical system remained exactly the same as did the
electrical system.
4.5 VARIATION OF pH WITH CONDUCTIVITY
The pH of the colliery waste-water was determined by
the addition of various quantities of acids and then
measuring the corresponding conductivity. This was also
carried out on the quartz suspension.
The apparatus set up to study the variation of pH with
conductivity comprises these equipments:-
a) pH-meter Model 7020
b) Conductivity Meter - Type CDM 2e No. 263049
c) Magnetic Stirrer MSl-Techre
The pH meter model 7020 is a direct indicating instrument
for the measurement of pH, with automatic or manual temperature
compensation, and millivolts.
It is designed for use with the following classes of
electrodes manufactured by Electronic Instruments Limited
(E.I.L) .
-82-
a) pH dual (Model SHDN33C)
b) pH measuring and reference pairs
c) Redox measuring and reference pairs.
The principle of the conductivity meter is that of an
ohm-meter. The conductivity of the conductivity cell is
read directly from the indicating meter, and the specific
conductivity of the test liquid at the specified temperature.
The conductivity cell type CD104 has three electrodes
in the form of platinum sheet placed in rings around a glass
tube and enclosed in a glass jacket. The top and the bottom
rings are connected and grounded to chassis through the shield
of co-axial cable while the centre ring is connected to the
centre conductor of the cable. This arrangement which is a
special feature of the conductivity cell has an effective
electrical shielding of the flows of currents between the
electrodes, thus enabling the cell to be used for measurements
in grounded vessels.
-83-
EXPERIMENTAL STUDY
CHAPTER 5
-84-
5.1 INTRODUCTION
The study involves the measurement of the electrokinetic
parameters such as; electrophoretic mobility, the zero point
of charge, the nature of charge and the iso-electric point.
The values of the electrophoretic mobility obtained can then
be used in the calculation of the zeta-potential.
The particle concentration should be so low as to induce
only the slightest haziness in the solution, otherwise
interparticle interference and multiple light scattering may
make the results invalid. Thus in order to demonstrate
electrophoresis the solid has to be in the form of particles
which are sufficiently small to remain suspended in the liquid
during the application of the electrical field and the
measurement of their velocity. The particles must also be
small enough or have a density close enough to that of the
suspending medium so that they will not fall out of the
stationary level under the influence of gravity while they
are observed.
Any charged particle suspended between the poles of an
electrical field tends to travel towards the pole that bears
the charge opposite to its own. When particles of several
kinds are present and each kind having its own characteristic
mobility, a number of particles may be measured so that the
distribution of mobility may be obtained. The rate at which
the particles travel is conditioned by a number of factors
including the characteristics of the particle, the properties
of the electrical field and environmental factors such as
-85-
temperature and the nature of the suspending medium. The
microscopic determination of electrophoretic mobility has
been applied successfully to such diverse aqueous systems
such as kaolinite (124)131) , and quartz (128) .
The electrophoretic mobility of a particle is approximately
proportional to its charge to mass ratio but unfortunately
this relationship is complicated by such factors as the
molecular volume of migrant, co-ordination of the migrant
with the molecules of solvent and the interference with
(132) migration by the supporting mediurrr ' .
Factors such as these make it very difficult to make
accurate quantitative predictions of electrophoretic
mobilities unless experimental data are available. When a
solution containing substances with different charge to mass
ratios is acted upon by an electrical field, the components
tend to migrate at different rates.
5.2 REAGENT AND PREPARATION OF SAMPLES
Analar (BDH, Chemical Ltd.) reagents were used.
Concentrations of 0.4M, 0.5M, 0.8M, and 1M HC1 were
prepared for use in studying the variation of pH with conductivity
of the suspension of the colliery waste-water and lOOppm of
Quartz suspension.
Various amounts of 0.4M. HC1 were added to 1000ml of the
suspension of the colliery waste-water to obtain different pH
values from which the electrokinetic parameters could be
determined experimentally.
-86-
Different amounts of 0.4M HC1 -were added to various
volumes of the suspension of the colliery waste-water to
obtain different pH values to carry out the experimental
work on flocculation.
Concentrations of 0.4M, 0.5M, 0.8M, and 1M. H2SO4
were prepared for use in studying the variation of pH with
conductivity of the suspension of the colliery waste-water
and lOOppm of Quartz suspension.
Various amounts of 0.4M H2SO4 were added to 1000ml of
suspension of the colliery waste-water to obtain different
pH values for the study of the electrokinetic parameters.
A concentration of lOOppm of Quartz suspension was
prepared using silica precipitated acid washed - (SiO2 » BDH
Chemical Ltd., Product No. 30058). Different amounts of
0.4M HC1 were added to 1000ml to obtain the various pH
values to be used to study the electrokinetic parameters.
Twenty - five percent weight per volume (25% ) of the
copper sulphate solution (CuSO,. 5H2O - BDH Chemicals Ltd.)
was prepared to be used as heat filters.
A concentration of lOOppm of Polyacrylamide solution
(BDH Chemicals Ltd., Product No. 29788, Molecular weight
over 5,000,000) was prepared to be used as the flocculating
agent for the suspension of the colliery waste-water.
Chloroplatinic acid (BDH Chemical Ltd., 5% ^ H2PtCl66H2 O)
was used as the platinising solution in the preparation of
the platinum black electrodes for the study of electrophoresis
-87-
The raw colliery waste-water was allowed to stand for
twenty-four hours and the suspension was decanted. This
suspension was used in the study of electrophoresis. Various
amounts of 0.4M HC1 and 0.4M H2 S04 were added to 1000ml of
the colliery waste-water to obtain the different values of
pH values for electrophoresis.
5.3 SAFETY PRECAUTIONS
The electrophoretic cell should be made of an insulating
material and designed so that any liquid spilling from the
apparatus cannot create an electrical hazard. The cell
should also be designed in such a way that the power supply
should be disconnected before the discharge of the suspension
from the cell.
To avoid the danger of making voltage measurements with
platinum wires (electrodes) being bare in the external circuit,
these terminals should be of the jack-type and the wire should
be passed through a perspex tube, making it impossible to
touch the live wires and cell should be closed.
Handling the raw colliery waste-water should be carried
out with the utmost care since Eschericia Coli (E.Coli) was
detected and it is an organism used as an indicator of
faecal contamination and possible presence of pathogenic
organisms.
-88-
5.4 EXPERIMENTAL PROCEDURE
Electrophoresis was performed on the silica (quartz)
suspension to confirm the validity of the modified micro-
electrophoresis equipment and then on the suspension obtained
from the raw colliery waste-water.
The variation of pH with conductivity and the various
amounts of the acids (HC1 and H-SO.) required to obtain
the pH values for electrophoresis were determined.
Finally the flocculation of the fines in the suspension
was carried out using the polyacrylamide.
5.4.1 ELECTROPHORESIS OF THE FINES IN THE SUSPENSION
OBTAINED FROM THE COLLIERY WASTE-WATER.
The experimental set-up used for the micro-electrophoresis
is shown in Figure 5.1.
The external electrical circuit was connected as shown
in Figure 5.1. The Regulated Power Unit (V.I) used in
converting the alternating (a.c.) to the direct current (d.c.)
was connected to the ammeter (A) and then the reversing key
which was in turn, connected to the electrodes in the micro-
electrophoretic cell. A voltmeter (V2) was connected across
the micro-electrophoretic cell to measure the voltage across
the cell.
The micro-electrophoretic cell was then placed on the
microscope stage and then connected to the tubes and the
funnels being used as the reservoirs (Rl and R2), as
-89-
illustrated in Figure 5.1.
All the taps (Tl,T2,T3,T4 and T5) are then closed.
The reservoir, Rl, was then filled with the suspension and
reservoir, R2, was then filled by opening taps Tl and T2.
Having filled the two reservoirs, the tap T2, was then closed
and Taps T3 and T5 were opened so that the micro-electrophoretic
cell could be filled. After filling the micro-electrophoretic
cell, there were a few bubbles in the cell which had to be
removed by closing tap T5 and opening Taps T2 and T4. This
allowed any bubble in the micro-electrophoretic cell and the
connecting tubes to move up into the reservoirs. When all the
bubbles had been removed the taps Tl, T2, T3, and T4 were
then closed.
The light source (L.S.), the monitor (M) and the
television screen (TV 1) were switched on. A calibrated
screen was already placed on the television (TV1), and was
used in measuring the distances travelled by the fine particles
in the cell.
Copper sulphate (25% ) was installed between the
microscope lamp and the micro-electrophoretic cell and this
was used as a heat filter.
The Regulated Power Unit (VI) was then switched on to
confirm if the other equipments were working correctly and
to see if the fine particles were moving in the cell and
then the power source (V.I) was switched off to allow the
suspension in the cell to attain equilibrium which usually
took between seventy - five and ninety minutes.
-90-
TV2
CR
TV 1
T3(
T2
— rfl ——r~^
t
Kt —— p-,i
, i-J ^ HF J I ———————— 1
L I
— ft-'Lei V2
X
T5
FIGURE 5 1 EXPERIMENTAL SET-UP FOR MICRO-ELECTPOPHORESIS
90A
Having obtained the equilibrium condition, the power
source and the light source were switched on, with the
micro-electrophoretic cell being held tightly on the
microscope stage. The microscope was then focused at the
appropriate level in the cell by the calibrated fine and
coarse adjustment of the microscope.
The time taken for several particles to travel given
distances on the television screen (T.V.I) were measured
using the stop clock watch (measuring to 0.1 second). The
times taken for several particles to travel different depths
in the cell were then measured.
This procedure of timing the particles were then repeated
for suspensions of different pH values to determine the zero
point of charge and to calculate the electrophoretic mobility
at different levels in the cell and hence the zeta-potential.
Having measured the velocity at each level in one direction
the polarity of the direct current was reversed since the
reversal cancels out assymetric effects and reduced the
polarisation effects.
5.4.2 ELECTROPHORESIS OF QUARTZ SUSPENSION
Electrophoresis of the Quartz suspension was carried out
to confirm the validity of the equipment designed. The
results obtained would then be compared with the work done
by Bhappu et al^ 128 ^.
The same experimental procedure described for the
suspension of the colliery waste-water in 5.4.1 was applied
-91-
to the quartz suspension. The only difference was in the length
of the micro-electrophoretic cell which in this case had
to be reduced from 8.0.10~2 (m) to 4.0.10~ (m) for the
quartz suspension, since the conductivity of quartz
suspension was so low compared to the suspension of the
colliery waste-water.
5.4.3 FLOCCULATION OF THE SOLID FINES IN THE SUSPENSION
(COLLIERY WASTE-WATER)
Different amounts of 1M HC1 were added to eight beakers
containing 200ml of the suspension (colliery waste-water)
to obtain the various values of pH 2.1, 3.0, 4.0, 4.9, 6.0,
7.0, 7.8 and 8.7 (original pH of the suspension).
An amount of 20ml of lOOppm of polyacrylamide was
added to each beaker containing the suspension and allowed
to stand for twenty four hours. Changes in flocculation were
assessed by measuring their optical densities.
5.4.4 THE CLEANING OF THE APPARATUS
The apparatus is demounted into three separate parts:-
the two reservoirs, the tube (piping) connecting the cell
and the reservoirs; and the electrophoretic cell.
The reservoirs are washed in a solution of teepol. The
tubes and the electrophoretic cell are also washed in the
solution of teepol and then cleaned by the ultrasonic
-92-
disintegrator (SONIPROBE TYPE 7530 A SERIAL No. 3892).
The reservoirs, the tubes and the electrophoretic
cell are then rinsed with de-ionised water and dried in
an oven at 100 C.
5.5 ANALYTICAL PROCEDURE
Electrophoretic mobility is defined as the ratio of the
velocity of the particles to the potential gradient.
The velocity is measured by timing a number of
particles travelling over a distance.
U = f (5.1)
where; u is the velocity (m.sec )
x is the distance travelled by the particles
in the electrophoretic cell, (m).
t is the time taken to travel the distance, (sec)
The distance x, is obtained by measuring the distance
X, travelled on the television and then dividing by the
magnification ratio between the monitor screen and the
magnitude of the objective lens, M.
x = jf (m) (5.2)
where; X is the distance travelled by the particles
on the television screen, (m).
M is the magnification ratio between the
monitor and the magnitude of the objective lens.
-93-
The potential gradient is defined as the ratio of the
voltage to the effective length between the electrodes.(4\
Three methods of measuring the voltage gradient are known^ ' j
E = Y (volt, rrf 1 ) (5.3)
where; E is the potential gradient, (volt, m )
V is the voltage across the cell, (volt.)
1 is the effective length between the
electrodes, (m).
The voltage, V, is measured by connecting a digital
voltmeter across the cell. The effective length is calculated
by the application of the following formula;
1 = R X A (m) (5.4)
where; R is the resistance across the cell (ohm).
X is the electrical conductivity, (ohm . m )
2 A is the cross-sectional area, (m ).
Hence the electrophoretic mobility, /u, is calculated as;
u 2 1 1 yu = (m .sec .volt )
The zeta-potential, f ; is then calculated by the
application of this formula;
£ = 4TTT1 . yu (volt) (5.6) D
where; ^ is the viscosity of the medium (kg m s )
D is the dielectric constant of the suspending
medium,
f is the zeta potential, (volt)
-94-
The point at which the zeta potential is zero is called
the iso-electric point (i.e.p.). In electrophoresis this is
the situation where the electrophoretic mobility becomes zero.
The zero point of charge (z.p.c.) of a mineral ean be
defined as the point on the pH scale at which the mineral
possesses no surface charge and the adsorption densities
of H30+ and OH~ are equal. At the zero point of charge
both the surface potential and zeta potential are zero.
Changes in suspensions due to flocculation can be assessed
turbidimetrically or even visually but the results are
difficult to interpret quantitatively. Changes in turbidity
normally assess the progress of flocculation, either by
jnephelometry (light scattering) or absorptiometry (light
transmission, measured by optical density).
The measurement of intensity of the transmitted light as
a function of the concentration of the dispersed phase is
the basis of turbidimetric analysis. Hence the method of
turbidimetry can be applied in the determination of the
suspended material in the colliery waste-water. The intensity
of the light scattered at any particular angle is a function
of the concentration of the scattering particles of their
size and shape, of the wavelength, of light, and of the
difference in refractive indices of the particles and the
medium.
Thus using the Perkin-Elmer (Lambda 3uv/vis) Spectro-
photometer and Recorder Model 561 (Hitachi Ltd., Tokyo,
Japan), the optical densities of the colliery waste-water
-95-
suspension at the various pH values can be determined directly
after flocculation with lOOppm of polyacrylamide flocculant.
Any settling of the colliery fines would tend to decrease
the optical density as measured through the medium.
-96-
INTERPRETATION OF DATA
CHAPTER 6
-97-
6.1 INTRODUCTION
Electrokinetic phenomena are only directly related to
the nature of the mobile part of the electrical double layer
and therefore can only be interpreted in the terms of zeta
potential or the charge density at the surface of shear.
Since the value of the zeta potential cannot be determined
experimentally, it is usually calculated from the electrokinetic
data, by measuring the electrophoretic mobility. These values
of dielectric constant and viscosity of the bulk solution
could be different from those values in the electrical doubleJayer
making the calculated value of the zeta potential uncertain (4,10,40,48,56,61,62)
It is frequently adequate to measure only the relative
changes in the electrokinetic properties such as the mobility
and the point of zero charge in the application of the
electrokinetic data in understanding the behaviour of the
mineral-water systems '. The calculation of absolute values
of zeta potential is not necessary in such analysis of data,
particularly if the experiments have been carried out at
constant ionic strength. However, it may be necessary to
use an absolute value of the zeta potential for more detailed
analyses of the influence of the electrical double layer
properties on the behaviour of mineral systems^ ' '.
The zeta potential or electrokinetic charge which
surrounds practically all particulate matter in water is
predominantly electronegative and it is usually strong enough
to result in significant mutual repulsion^ 69 > 141 ' 142 ).
-98-
Therefore finely divided solids such as clay tend to remain
suspended. If the charge on these particles is reduced to
zero or near zero the repulsive forces are reduced or
eliminated which result in agglomeration and subsequently
in sedimentation. The efficiency of the process of the
clarification of the colliery waste-water (effluent water) is
markedly influenced by agglomeration. Therefore zeta potential
analyses may help to evaluate the flocculating characteristics
and aid in determining the type of flocculants most useful
and effective in the clarification of the colliery waste-
water .
6.2 THE CONCEPTS OF ELECTROPHORETIC MOBILITY
The theory of electrokinetic phenomena, one of which is
electrophoresis was first presented by Helmholtz ', in
which he concluded that the electrophoretic mobility is
proportional to the zeta potential and not the charge of the
colloidal particle. The derivation of Helmholtz was then
improved by Smoluchouski^ , to be completely consistent
with this more modern view of the double layer^ '.
Smoluchowski s equation is identical with that developed by
Helmholtz except for the inclusion of the dielectric constant.
Overbeek 1 ' has fdund out the stability of hydrophobic
colloids to be closely related to the zeta potential as
calculated from electrophoretic mobility by the application
of electrophoresis. To keep the hydrophobic suspension stable,
-99-
it was determined to be necessary that a specified minimal
zeta potential (critical potential) was found. This concept. , , , , .^ (4,10,37,40,50,73,96,124) has been widely used by many authors v ' ,
and although the zeta potential has a less prominant position
' 56 ', electrophoresis still remains an important source of
information about hydrophobic colloids. The relation between
stability and electrophoresis is much less prominent in
hydrophilic colloids since many hydrophilic colloids may
remain in colloidal solution even when their electrophoretic
mobility has been reduced to zero. Nevertheless electrophoresis
would retain its significance in the determination of the
iso-electric point and the charge of the particles outside
the iso-electric point.
( 59} A number of workers including Henry x ', Lyklema and
Overbeek^ ' and Hunter*1 ' have investigated the various
corrections required to preserve the validity of Smoluchowski's
equation. Retardation^ relaxation and viscoelectric effectsrequiring
have been considered the most significant aspects correction.A
( 59 1 The retardation effect has been analysed by Henry '
and shown to be a function of the ratio of the radius of the
particle to the thickness of the electrical double layer (ka).
The relaxation correction is more complex because it depends
strongly on the ratio of the particle radius to the electrical
double layer thickness and it is also influenced by such
factors as the magnitude of the zeta potential, the valency
and the mobility of the ions in the solution.
-100-
The possibility that the viscosity and permittivity
constant terms in the Smoluchouski's equation could be
influenced by the locally high-field strength gradients of
the electrical double layer has been considered by Lyklema
and Overbeek^ 61 ) and Hunter^ 62 ).
Wiersema et al have carried out the calculation
of the electrophoretic mobility of a spherical colloidal
particle.
(12 ) In a comprehensive review Overbeek et al ' considered
the effect on zeta potential calculation of mixtures of
electrolytes, errors in the Gouy-Chapman theory, the visco-
electric effect, particle conductivity, non-rigid particles,
particle chape, Brownian movement and colloid concentration.
More recently Morrison^ ' has considered in detail the
effect of the particle shape and has concluded that equations
developed for spheres are applicable to other shapes.
Despite the attention given by many workers to the
calculation of the zeta potential from the electrophoretic
mobility data and despite the improvements which have been
made, it is obvious that there are still areas of uncertainty.
-101-
6.2.1 SMOLUCHOWSKI * S EQUATION
Smoluchowski s analysis was carried out in the first
instance by studying electro-osmosis and his electrophoresis
equation was derived by considering electrophoresis as the
reverse phenomenon of electro-osmosis and therefore for the
relative motion of the solid and liquid, the same equation
should apply to both phenomena.
In direct application to electrophoresis, Smoluchowski
deduced this expression;
" - I -It was claimed by Smoluchowski that equation (6.1)
was valid for rigid electrically insulated particles of any
( 59) shape subject to these four restrictions .
a) That the usual hydrodynamical equations for the
motion of a viscous fluid may be assumed to hold
in the bulk of the liquid and within the double
layer;
b) That the motion is streamline and slow enough for
the inertia term in the hydrodynamic equation to
be eliminated;
c) That the applied field may be taken as simply
superimposed on the field due to the electrical
double layer;
d) That the thickness of the electrical double layer
is small compared with the radius of curvature at
any point of the surface.
-102-
6.2.2 HUCKEL'S EQUATION
. . ( 44 Debye and Huckel v ' criticised Smoluchowski s equation
by stating that while Smoluchowski s equation is valid for
particles of any shape, subject to the four restrictions,
the constant is not always equal to -=- but varies with the
shape of the particle, and this constant could only be
determined for each shape by the application of a detailed
hydrodynamic analysis of the motion of the liquid. Huckel '
has since published the constant to be -g - for a spherical
particle. Therefore Huckel' s equation is expressed as:
(6 2) tb> '~ E ~ 6-TTT] -
( 44 ) i Debye and Huckel ' also stated that the constant -r~— ,
could be used for particles of cylindrical shape.
Many authors including Hunter ' , Shaw ' and Overbeek
have reviewed Huckel s equation. Shaw ' found out that
Huckel 1 s equation is valid for small "ka" which is the ratio
of the radius of curvature to the electrical double layer
thickness and is not applicable to
particle electrophoresis in aqueous media.
* £44.') Debye and Huckel ' used the same assumptions by
Smoluchowski l ' but could not show where the analysis of
Smoluchowski was not valid. There was then a contradiction/ 59 \
which remained unsolved for several years until Henry in
a reviewed analysis of the whole problem reconciled the two
contradictory points of view.
-103-
6.2.3 HENRY'S SOLUTION TO THE CONTRADICTION BETWEEN
SMOLUCHOWSKI AND HUCKEL THEORIES
The analysis carried out by Debye and Huckel ' was(59 ) examined by Henry ' because the conclusion that the
electrophoretic mobility of a particle should depend upon
its shape appeared to be at variance with experimental facts.
Henry^ ' found out that Debye and Huckel assumed the
applied potential gradient to be parallel to the x-axis
everywhere and to be undisturbed by the presence of the
particle, but this would only be the case if the electrical
conductivity of the particle is identical with that of the
medium which would seldom occur in practice. But Smoluchowski
considered an insulating particle and therefore took
the deformation of the applied electrical field by the
insulating particle explicity into account. Hence the
difference between the concepts of Smoluchowski^ ' and
Debye and Huckel^ ' is the geometry of the applied electrical
field. The conception of Debye and Huckel is quite justified
in using electrolytic solutions since the extension of the
electrical double layer is so much larger than the dimensions
of the ions that the deformation of the field which is only
felt in the immediate vicinity of the ions is practically
without the influence upon electrophoretic retardation ,(59) Henry employed the same analytical methods as Huckel
but using a particle of different specific electrical
conductivity from that of the medium. This method was applied
to spheres and cylinders in both axial and tranverse positions
-104-
and the results obtained when subjected to Smoluchowski ' s
four restrictions, then equation (6.1) is valid in each
case and hence Henry derived the following for both insulating
sphere and a cylinder which agreed with Smoluchowski
In deducing his equation (6.3) Henry found out that the
deformation of the applied electrical field is strongly
dependent on the electrical conductance of the particle.
This deformation and its influence upon the electrophoretic
mobility is determined by the ratio of the electrical
conductivities of the particle to the surrounding
liquid.
Shaw has discussed the general electrophoretic
equation which Henry derived for both conducting and non
conducting spheres which takes the form,
l + * F < to > < 6 - 4 >
where F(ka) varies between zero for small values of ka and
1.0 for large values of ka and
> k - k,A = o _____ 1 I f- /, -, \ 2k + k~~ (6.4.1) o + kl
where kQ is the specific conductance of the bulk electrolyte
solution and ^ is the specific conductance of the particles.
For non-conducting particles, X= 0.5, and equation
(6.4) can then be expressed as
f(ka) (6 - 5)where f(ka) varies between 1.0 for small particles (Huckel's
equation) and 1.5 for large ka (Smoluchowski s equation)
-105-
Therefore the zeta potential calculated using the
Huckel for ka = 0.5 and from the Smoluchowski equation
for ka = 300 differ about one per cent from the corresponding
zeta potentials which have been calculated using the Henry
equation. It should also be noted that Henry's equation is
based on these assumptions:-
#»
(a) Debye - Huekel approximation is applied;
(b) applied field and the field of the electrical
double layer are simply superimposed, because the
mutual distortion of these fields could affect the
electrophoretic mobility;-
(i) through abnormal conductance (surface conductance)
in the neighbourhood of the charged surface;
(ii) through loss of the double layer symmetry
(relaxation effect)
(c) the dielectric constant and viscosity were assumed
to be constant throughout the mobile part of the
double layer.
For low values of ka (small spheres) Huekel s equation
is valid and for large spheres the Smoluchowski s equation is
then valid.
6.3 CONDUCTION EFFECTS IN ELECTROPHQRESIS
The conduction effects in electrophoresis can be
attributed to :-
a) The particle conductance and shape,
b) Surface conductance.
-106-
The effect of the conductivity of the particle determines
how the presence of the particle distorts the applied electrical
field. Henry has considered the spheres of different
conductivity and established a relation as expressed in
equation (6.4). For a highly conducting sphere the behaviour
is unaffected for ka <^ 1, since the effect of deformation
of the field is only important if electrophoretic retardation
is important and it is not for ka <^ 1. As ka increases and
electrophoretic retardation becomes more significant, the
electrophoretic mobility decreases until ultimately at very
large ka, it falls to zero. It is doubtful when in any
ordinary circumstances there is any need to take into account,
. . (4) the effects of high particle conductivity '. Even metallic
dispersion appears to exhibit normal electrophoretic behaviour
{9) which Overbeek v ' attributes to the effects of polarisation.
Unless there is evidence to the contrary, then all particles
may be treated as insulators with the exception of liquid(4)metallic dispersion '.
The distribution of ions in the diffuse part of the
electrical double layer gives rise to an electrical conductance
in this region which is in excess of that in the bulk
electrolyte medium. Surface conductance will affect the
distribution of the electrical field near to the surface of
a charged particle and so influence its electrokinetic
behaviour^ '. The effect of surface conductance on the
electrophoretic behaviour can be neglected when 'ka' is small
because the applied electrical field is hardly affected by
-107-
uE
Df4T17]
k
k +ko s
a
the particle size in any case. When "ka" is not small, the
calculated zeta potential may be significantly low on account
of surface conductance.
Shaw has discussed the Booth and Henry equation
which relates electrophoretic mobility with the zeta potential
for non-conducting spheres with large "ka" and when corrected
for surface conductance can be expressed as:-
(6.6)
where k is the specific conductance.S
Experimental surface conductances which are not very
reliable tend to be higher than those calculated for the
mobile part of the electrical double and the possibility of
(9) surface conductance inside the shear plane '. There is
therefore some uncertainty regarding the influence of surface
conductance on electrophoretic behaviour.
The expression established by Henry in equation (6.6) is
seldom used because the modern theory of electrophoresis
takes the surface conductance into account by dealing explicitly
with the electrophoretic mobility of the electrical double
layer ions. Provided the surface conductivity is normal
(equal to what would be expected from the known concentrations
and mobilities of ions in the double layer) its effects are
(4) taken into account in the treatment of the relaxation effect '.
-108-
6.4 THE INFLUENCE OF THE DEFORMATION OF THE ELECTRICAL
DOUBLE LAYER UPON ELECTROPHORESIS
The effect of relaxation arising from the deformation
of the electrical double has a retarding influence on electrophoresis* 4 ' 19 ' 26 ' 56 ' 124 ). In an applied electrical
field the charge of the diffuse double layer is displaced
in a direction opposite to the movement of the particle
and this does not only retard the electrophoresis by its
movement but also by the resulting dissymetry of the double
layer sets up a retarding potential difference. Corrections
(9) have been suggested by several authors including Overbeek 'and Booth* 138) .
In the stationary state which is reached shortly after
the electrical field is applied in electrophoresis, the particles
move with a constant velocity and the total force on the
particles is zero. Therefore in the first approximation the
electrical force on the charged particle is equal to the
hydrodynamic frictional force on the particle by the liquid.
A detailed analysis of the problem illustrate that two
additional forces oppose the electrical forces namely* 4 ' 10 ' 26 ' 56 '^
a) An additional frictional force results from the
movement of water with counter ions which move in
a direction opposite to that of the particle. This
force is known as the electrophoretic retardation
force.
-109-
b) A second retarding force is caused by a
distortion of the diffuse atmosphere of counter-
ions around the particle. This force is called
the relaxation force.
Since the counter-ions move in an opposite direction,
the electrical double layer in front of the particle must
be constantly restored as it is broken off behind the particle
The restoration of the double layer takes a finite time known
as the relaxation time. Therefore the electrical double
layer will be shifted somewhat with respect to the particle
and will exert an electric retardation force.
The complete formula relating the electrophoretic
mobility and the zeta potential is derived by the theoretical
evaluation of the four forces acting on the particles. These
four forces are namelys-
a) electrical force on the charged particle,
b) hydrodynamic frictional force on the particle
by the liquid,
c) electrophoretic retardation force,
d) relaxation force.
Since such an evaluation is possible only for limited
cases no formula is available which covers every situation
(26)
-110-
6.4.1 EFFECT OF ELECTRQPHORETIC RETARDATION
The action of the electrical field on the double layer
ions which causes the liquid to move is called the electro-
phoretic retardation because this action causes a reduction
in the velocity of the migrating particle.
Smoluchowski's ' treatment assumed that this was the
dominant force and that the particle's motion was equal and
opposite to the liquid motion.
Huckel ' on the other hand, made proper allowance
for the electrophoretic retardation in his analysis. It
turns out, however that his equation is valid for small
values of *ka' when electrophoretic retardation of the
particle is relatively unimportant and the main retarding
force is the frictional resistance of the medium.(139} Dukhin and Derjaguinv ' showed that the ratio of the
retardation force to the viscous resistance is of the order
1 ka' . Therefore for small particles, although the retardation
force acts across the whole double layer, very little of it
is transmitted to the particle.
The electrophoretic retardation remains important in
the description of electrolytic conduction where "ka" is very
small and could be attributed toj-
a) the movement of ions of both positive and
negative signs,
b) the calculation of the interaction effects for
large number of ions.
-Ill-
For large particles with double layers essentially all
of the electrophoretic retardation is communicated directly(139) to the particle VJ- J '.
In conductance of strong electrolytes the influence of
the relaxation effect is of the same order of magnitude as
the retardation caused by the motion of the ions of the
atmosphere, and therefore in order to arrive at a complete
description of electrophoresis, it is necessary to include
the relaxation effect.
6.4.2 RELAXATION EFFECT
(59) The calculations made by Henry ' were based on the
assumption that the external field could be superimposed on
the field due to the particle and that the latter could be
described by linearized version of the Poisson-Boltzmann
equation. Certainly this is not exactly the case, as the
particle and the outer part of the electrical double layer
having opposite signs of charge, move in opposite directions
by which means the original symmetry of the double layer is disturbed (56) .
The movement of the particle relative to the mobile
point of the double layer results in the double layer being
distorted because a finite time known as relaxation time, is
required for the original symmetry to be restored by diffusion
and conduction* »40,56)^ ^^ outer part of the double layer
then lags behind the particle. The resulting assymetric
ionic atmosphere exerts an additional retarding force on the
particle which is known as the relaxation effect and this is
-112-
not accounted for in the Henry equation (6.4). Relaxation
can be safely neglected for both small and large values
of "ka" (ka<0.1 andka>300) but it is significant for the
intermediate values of "Ka", especially at high potentials
and when the counter ions are polyvalent and, or have low
mobilities(40 ' 56) .
Overbeek 1 ' and Booth^ ' derived equations for spherical
particles which allow for retardation, relaxation, and
surface conductance in the mobile part of the double layer
and which expressed electrophoretic mobility as a power
series. Due to mathematical difficulties these equations were
only solved for a restricted number of terms. At higher
potentials the relaxation effect was overestimated.
The treatments of Overbeek and Booth have now
been superseded both in the range of validity and convenience
by that of Wiersema et al^ , in which the appropriate
differential equations have been solved without approximation
using an electronic computer. The main assumptions applied
are:-
a) The particle is a rigid, non-conducting sphere
with its charge uniformly distributed over the
surface,
b) The electrophoretic behaviour of the particle is
not influenced by other particles in the dispersion,
c) Dielectric constant and viscosity are constant
throughout the mobile part of the double layer,
d) Only one type of each positive and negative ions
are present in the electrical double layer.
-113-
/ Q \
Overbeekv ' pointed out that, inter alia, the
relaxation effect may give important corrections if the
zeta potential is not very small for values from 0.1 to 100.
This therefore means that, very often conclusions as to the
value of the zeta potential derived from the electrophoretic
measurements are open to serious doubt.
6.5 DIELECTRIC CONSTANT AND VISCOSITY
In the calculation and interpretation of the zeta potential
there arises further difficulty if the electrical field
strength which is close to the shear plane is high enough
to significantly decrease the dielectric constant and increase the viscosity by dipole orientation(11 ' 40 > 61 ' 52 13V ' 14°' 141 ' 142 > .
Lyklema et al ' examined the variability of the dielectric
constant and viscosity in the electrical double layer and
carried out correction of the Helmholtz-Smoluchowski equation
for the variability of the viscosity. The dielectric
constant in the inner region was deduced from the double
layer capacity evidence to be smaller than that of the bulk
liquid. This is due to the saturation effects caused by the
high field strengths in the double layer and to the structural
influence of the adjacent phase. Lyklema et al ' however
concluded that it is mostly justified to use the bulk value
of the dielectric constant in the electrophoresis equation
of Helmholtz-Smoluchowski, but in all cases the viscosity was
determined to increase with the electrical field strength.
-114-
A significant and positive visco-electric effect
would result in the effective location of the shear plane
moving away from the particle surface which would result
in increasing the zeta potential and or increasing the
thickness of the electrical double layer^ 4 ' 40)141 * 142 ).
Therefore the zeta potential would vary and not be constant.
Recent investigations by Hunter ' suggest, however,
that the viscoelectric effect was overestimated by Lyklema
et al and that is significant in most practical situations,/ c 9 \
Hunter also reviewed the influence of viscosity on the
zeta potential, variation of the dielectric constant
(permittivity) with field strength, and influence of surface
charge density on the position of shear plane.
-115-
RESULTS AND DISCUSSION
CHAPTER 7
-116-
7.1 INTRODUCTION
Most suspended particles in water are charged and the
electrical repulsion between them tends to prevent aggregation.
Many additives can reduce the particle charge and hence cause
destabilization of the suspended particles. In such cases,
the measurement of the particle charge as a function of the
reagent dosage can give a good indication of the optimum condition
The most common approach is to measure the zeta potential
of the particles.
There are several reports in the literature^ ' ' ' '
69,73,76) indicating that the zeta potential is a useful
means of controlling practical flocculation processes. While
this seems reasonable in certain cases, there are other
cases where the relationship between the zeta potential and
colloid stability is not so straight-forward.
The nature of the charge or charges on the colliery
fines were determined and also the electrophoretic mobility
which was used to calculate the zeta potential. The point
of zero charge (zpc) and the iso-electric point (iep) were
also determined.
The pH value at which the zeta potential could be
reduced to, in order to carry out the flocculation of the
colliery waste-water was also carried out. Finally the
optical densities were also determined after flocculation.
The microscope was focussed at different levels of depth
in the electrophoretic cell and the time taken for the
particles to move through the distance was measured.
-117-
These measurements were taken in one direction and then the
voltage was reversed (circuit reversed) so that the particles
could be timed in the reverse direction (opposite direction).
The detailed results have been tabulated in the
appendices B, C, and D.
7.2 ELECTROPHQRESIS OF 100 ppm QUARTZ SUSPENSION
The validity of the experimental set-up was confirmed
by the determination of the nature of charge, electrophoretic
mobility and the zero point of charge of quartz.
The quartz particles were determined to be negatively
1 2 ft ) 'charged and this agreed with the work of Bhappu and( A\
and Hunter ' .
The graphs of the mobility profile at different pH
values against the various levels of cell depth within the
electrophoretic cell compared favourably with those obtained
by Hunter (4) Shergold et al (129) and Prasad (70) . These graphs
can be seen in Figures 7.1 to 7.6. At a particular cell depth
there were obtained different electrophoretic mobilities of
the particles. This could be explained by the fact that there
were different particle sizes in the lOOppm quartz suspension.
The graphs of the mobility profile at the same depth
but against different pH values can be seen in Figures 7.7
to 7.13. It can be seen on these graphs that between the pH
values of 5.6 and 4.0, all the quartz particles moved towards
the anode, between 4.0 and 3.8 some moved towards the anode
-118-
and some towards the cathode, and at pH values less than
3.8 the particles moved towards the cathode.
The point of zero charge was determined to be at the
pH value of 3.8 which compared favourably with the values
obtained by Hunter and Bhappu and Deju '.
-119-
FIG.
7.1
ro o
^
•TO
WARD
S AN
ODE
a iL Id llfl. 0^6.
0 */ f
ELOW
PHOR
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OF
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QU
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=5-2
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-12
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ro
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FIG.
.
AT
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3-6
37
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.
7.2 TOW
ARDS
*2AN
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24 li. H H M Qfl.
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ELEC
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-(? 1
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IRC
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-121-
FIGU
RE. 7
.3
ro
ro
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SUSP
ENSI
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• V2
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, .E
LECT
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lOOp
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3-6
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3 :8
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5I»10-2
.
-122-
FIGU
RE.
7.1,
ELEC
TROP
HORE
SIS
OF l
OflP
fm
QUAR
TZ
SUSP
ENSI
ON
AT
pH=3
-8
TOW
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S.:*
CA
THO
DE
^
ifl.
| re CO i
Zii
1^ fli 0 3
5 3-
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• ;
3-7
3-8
3-9
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t it-
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DS^!
CATH
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pH
=3fl
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5 3^6
'
3*7
3-8
3^9
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l»-'l
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4
4 5 M
O2)
-123-
FIGUR
E. 7
.5
_jELE
CTW
PHOR
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^OF
tOOp
pm
QUAR
TZ
SUSP
ENSI
ON
rv>
^
soTO
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CA
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f) *T
pH
=3b
~^~
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— "• —
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S OF
10
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QU
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xi«
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-12
4-
FIGUR
E. 7.6
en
ELEC
TROP
HORE
SIS
OF 1
00pp
m QU
ARTZ
SU
SPEN
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TOW&
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CATH
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5-0 ML 31 tfi. vo 0 3jxif
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pffcS
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l»N
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ft
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TOWA
RDS
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.EUZC
TRCP
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SIS
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100p
pn
QUAR
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SUSP
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$
AT
pH=3
0 -C
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36
•
3^7
3^
31?
Jo
<,'-1
(,-'2
V3vi
u
-125
-
FIGURE. 7.7
VARIATION OF pH WITH MOBILITY AT DEPTH d=370. 10 m
H
li
2JL
Ul
TOWA8DSt
TO CAT
/ARDS HODE
0 1-0 ~?0 ?0 VO ^ 5-
vo
10^
2J1
r I
VARIATION OF pH WITH MfBLITY AT DFPTH d=3-80.10 2 m
TOWARDSAN
t
ODEk
TOvJ .. ..iRDS ' ' 'CATHODE
o — -0 2-0 >0 VO L 5-
/
OMO8 ]
0(«108 |
-126-
FIGURE. 7.6
VARIATION OFpH WITH MQttLlTY AT DEPTH d= 3-90.10 m
[>H
to.
11
M.
1-0 2-0 3-0 VO 5-0|x10S]
VARIATION OF pH WITH MOBILITY AT DEPTH J=V0.10nv
pHJ.
VO
aa
AfCS
TOWARDS CATHODE
1-0 2-0 3-0 j,o_^ ^ »oi.
-127-
FIGURE, 7.9
pH 5JL
4-0
12.
ZJL
VARIATION OF pH WITH NOBILITY AT DEPTH d=VlO.
TOWARDS
1-0 2-0 3-0
5-0pH
2-0
VARIATION OF pH WITH MOBILITY AT DEPTH
TOWARD S CATHODE
1-0 2-0 3-0 S-ONKfl
-128-
FIGURE. 7.10
5-0
OF pH WITH MOBILITY AT DEPTH j=t»-30.-2
TOWWtfB ANODE
TOWARDS . ••••" CATHODE
24
gl——————————————,__________,——————————————,——————————————p_10 20 30 U 0
VARIATION OF pH WITH MOBILITY AT DEPTH d=3?0 llftn — CIRCUIT REVERSED
PH
VOl________
TOWARDS CATHODE
-4 .-A5 OMO ]
1-0 2-0—i—
3-0 5-01x10]
-129-
FIGURE. 7.11
.
l±
to.
0
>H
vo
M
M.
]±
0
TOWARDS t
TOWARDS CATHODE
K) 2-0 3-0 4-0 ^ 5-0[»io8 ]* /
VARIATION OF pH WITH MOBIUTY AT DEPTH d= 3-9. IC^m — CIRCUIT REVERSED
T»SA .
TOWAflDS " " " 'CATHODE
1-0 2-0 3-0 VO . /, 5-0[xfQ8 l
-130-
FIGURE. 7 12.
-2
50
3-0
2-0
VARIATION Of tH WITH MOSLITY AT DEPTH d»4-Q.1Qm— CIRCUIT REVERSED
TOWARDS
1-0—i—
2-0 3-0—l—vo 5-0 WO8 ]
VARIATION OF pH WITH MOBILITY AT DEPTH d=MO. ib2m — CIRCUIT REVERSED
k
40
11
20
La
0
TH! fP
TOWARDS ........ CATHODE
1 0 2-'o >'0 4-0 / 5-———————— »/t OHO8 ]
-131-
FIGURE.?. 13
-2VARIATION OF rt WITH MOB11JTY AT DEPT^ d = 4-20. 10m — CIRCUIT REVERSED
pi 4
M)
TOWARDS ANCX
CATHODE
M
1-0 2-0 3-0 ^-0 -> 5-0 I
VARIATION OF pH WITH MOBIUTY AT DEPTH d=4 30 10 m — CIRCUIT REVERSED
pH
34 TOWARDS CATHf--HODE
1-0 2-0 3-0 5-OWO8]
-132-
7.3 ELECTROPHORESIS OF COLLIERY WASTE-WATER - (HC1)
The origin of the surface charge which forms on the
minerals immersed in water is very important in mineral
processing since a large amount of the flotation, rheological
and flocculation (aggregation) of the mineral pulps is
influenced by this charge. Much of the charging mechanism
at the mineral - water interface has been developed from the
results of the electrokinetic measurements of the zero point
of charge. The different pH values were obtained by the
addition of hydrochloric acid.
The charges on the fines in the colliery waste-water were
determined to be both positive and negative as can be seen in
the mobility profile at the various pH values against the
different levels of cell depth within the electrophoretic
cell. (Figures 7.14 to 7.23)
On viewing these fines under the microscope these coal
particles appeared to be coated, and this was further confirmed
by scanning electron microscopy. They were also found to be
aluminium silicates from x-ray crystallography. The coating
on the coal particles were determined to be a layer of
aluminium silicates which are basically colloidal clay
particles, the hydrophilic nature of which is able to prevent
the attachment of an air bubble to the hydrophobic coal
surface.
Slime particles of near colloidal size are able to coat
coal particles in flotation pulp. It should be remarked
here that the National Coal Board uses the Froth Flotation
-133-
reagent of twenty five per cent Tar acids in gas oils.
Hence coating could occur whenever the particles carry
charges of opposite sign or small charges of the same sign,
or in some instances when the particles of one species carry
a large charge and these of a second species carry a very
small charge. The magnitude of the charge is measured in(144) terms of the zeta potential
It would seem unlikely for a clay slime which is
negatively charged to coat the surface of a coal particlecarrying guite a high potential of the same sign. However,
( 2 fi ^ Van Olphen observed that sub-micro-scopic particles ofmontmorrilonite clays exist as thin platelets and from
experimental evidence he concluded that they carry a dual
electrical charge. Hence the dual charge on the fines in
colliery waste-water appears to be due to the imperfections in the silicate crystal lattice structure in which the flat
surfaces are negatively charged whilst the exposure of
alumina along the edges of the platelet is responsible for the positive charge.
It could be possible that the positively charged edges
of the clay particles would be attracted by the negatively charged coal surfaces so that the clay particles would
become oriented perpendicularly to the surface, and thus being
more remote, the negative charges on the flat clay surfaces
exercises less repulsion and equilibrium may be possible.Several investigators^ 145 ' 146 ' 147 ^ have indicated that
positive sites exist on the edges of clay crystals owing to
-134-
the exposed lattice aluminium atoms at the locations.
Consequently clay particles possess two oppositely charged
double layers, one associated with the face of the clay plates
and the other associated with the edges of the plates.
The graphs of the mobility at different pH values on
using hydrochloric acid against the various levels of cell
depth compared favourably with each other with the reversal
of charge occuring at pH value of 4.9.
-135-
=7.
FIGURE. 7.14.
ELECTROPHONE SIS OF COLLIERY WASTEWATER AT pH=S-6-
12.
to. TOWARDSANODE
5 3-6 3-7 36 39 0 V1 V2
1-0TOWARDS CATHODE
-136-
ifl
til
lifl.
2itt
FIGURE. 7.1B
WASTFWATFR AT PH=a-&—CIRCUIT REVERSED
•5 3-6 3-7 3-fi 3-9 4-0
TOWARDS CATHODE
4-3 J-sixib1 ]
-137-
FIG
URE.
7.1
6
M07J ISL
LQ.
UQ.
2JL
IEQB
QB
•5 3-6
OR
F5K
Of
CO
IlffB
Y
WA
TFW
ffFQ
AT
r,H
=7.R
; t
TOWA
I AN
D i
T
1 1
3-7
3-8
39
4 X
*DS
DE IL
1 1
10
4-1
V2
V3
CATH
ODE I
I i
!
MO2]
A
M 0 3
UQ,
3JL
ELEC
TROP
HORE
S1S
OF C
011I
FRY
5 3-
6
; !
I
TOW
AI
ANC /
— T
---T
--
T~
—3-7
3-8
3-9
if ^
TOW
Af
CATH
(
CIR5
W
ASTE
WAT
ER A
T pH
r7-fi
-R
EV
30S
OE --
- 1
1 1
0 V
1 ^-
2 V
3
^ »S
)DE !
3
1
.UIT
FR
SED -^
•5[p1
0
-138
-
FIG
URE.
7 1
7.
CO 10
h Y4-0
iA Lfi
H 0 3
UL
2_0
BH
TRnP
H
3-6
OR
EaS
nFC
OLL
lFR
Y V
TOW
A AN
D i
3-7
3-8
3-9
/. T
TOWA
CATH
C
MS
IE W
ATER
AT
rt-T
O
RDS
DE 0 V1
W
4-
3—
——
— »d
r RDS
)DE :
j
i j
i f
1 k-k
if5
|xfo
2 ]
> 1 ML 0 3
1JL
2JL
' H,
CIRC
UIT
ELEO
RQpH
nREs
is OF
coL
UEPn
r WA
STFW
ATER
AT nH
=T-n-
RFVE
R?;Fn
•5 3-6
! i
TOW
/AM
I ^
— i —
——
i ——
— i
3-1
3-8
3-9
(, i
TOW
A CA
TH
\RDS
3D
Ek
I i
I •0
V1
l,-2
^ I.-
3
^DS
ODE i
— I —
——
-139
-
FIG
UR
E.7
-18
EIEC
TOPH
OHE3
S OF
COLU
ERY
WAS
TEW
ATER
AT
pH^i
-O
O I
tfl
^. H ^•0
1 -0 0 3-
Ul
U vn /L
fcl
!x^
5 3-
6
. i
M
! '
i
TOW
ARDS
ANO
3-7
3-V
3-9
k
TOW
AF
* 0 fc'
l <, ;
2 U-
3
DSCA
THOD
E
,1
ft
! 1
I1 i
: i i
5 MO
2 ]
. fl E
LECT
ROPH
ORES
IS
OF
COLU
ERY
WAS
TEVA
TER
AT d
fcfrO
-BF&
FlKF
Dl^
TU J
V, ,
0 } 14. ta itt
f
kfi
ifl.
Ixflt7
!
5 34
«
i
TOW
A ANJ
3>7
3!8
3 !9
V
TOW
A CA
THtRD
S DD
E
0 *.'
•! 4-
2 ^-
3
i RDS
)DE i
i >
<
: .
i I
V-4
V
-14
0-
FIG
URE.
7.1
9
M
MA tt
I ka 11 bi 0 3
tfl.
3JL
L fcfl.IllK
IBQ i
5 3-6
>HOf
i£SIS
OF
COLU
ERY
WAS
TEW
ATER
AT
pH=
5-2
i
i
TOW
/ AN
Q 1
3-7
3-8
3-9
V
TOW
CA
TH
r
i i
i0
V1
V7
V3
ras
DDE 1
1 i
j i
. i
VI,
(»•
h fctt
ii 2-Q
1-0 0 3
tfi M M Iv
tf'
ELEC
TRCP
H
1 •5
3-6
uDR
ES1S
OF
COLU
ERY
WAST
EWAT
ER A
T pH
=S-2
- R
.l'
'l TOWA
J AN
D >
\ 1
1 3-7
3-
8 3-9
If
F t ——
i ——
n — i —
TOW
ARDS
CA
THOD
E |
; i
Oil
VERS
ED
15 W
O2]
-14
1-
FIGU
RE.
7.20
ro
i^i
FJRl
HlPH
*.
tffl
3^0 0 UI
2JL
10.
I4jl
L
4 (V
I
——
——
1 ——
5 3-6
JHES
IS
OFC
OIL
IER
Y W
ASTE
WAT
FR A
TpH
rM
i
i !
1
! '
i
t
1 i
i3-7
3-8
39
It \
TOWA
® 0 lt-
1 V2
V3
^RDS
CATH
ODE
i ,
ii
• •
|
1 It-It
It-
CIRC
UIT
<ioi
h AiO <^.Q 3*0 0 3
1:0.
UL
3JLJL
EHBD
J
*
•5 3-
6
HDRE
SIS
OF C
OLLI
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WAS
TFW
ATFR
ATp
Hrt
i
i r
i
3-7
3-8
3'9
d
i
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i•0
V1
it'2
it'3
TOW
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CA
THOD
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i ;
i;
j
9-R
EVER
it'll
it-5
SED
-14
2-
FIG
URE.
7.2
1
CO I
,j7,
.ELE
CTRO
PI
f-""V
fi
i,
4^0 34 2jO
& °3
UL
M
,
31 inH
» A ' 5J
.("
lO'l
•5 3.'
6
HO
KSE
OF C
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RY W
ASTE
WAT
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T pH
^W)
i !
!
i :
i • i
TOW
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3^7
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i,- \
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THfP5 0
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t :
11
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I.5U
102 ]
ILEO
RQPU
QRE
SJS
an ktt
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WAST
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TER
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CATH
DOE
-14
3-
FIG
URE
.?. 2
2
WrJ]
ELE
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PHOR
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OF
COLL
IERY
VKS
TEW
ATER
AT
pH=2
-7I«
IUJ
5jO
t 1
3_0 ia 0 3
iO WL
r Ixf?
)
5 3-6
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3-7
3'8
3-9
4
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CATH
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7.4 VARIATION OF pH WITH MOBILITY AND ZETA POTENTIAL - (HC1)
The graphs of mobility and zeta potential profiles at
the same depth but against the different pH values have been
illustrated in Figures 7.24 to 7.47 using hydrochloric acid.
For pH values between 8.60 and 5.20 and between the_2
cell depth of 3.75 to 3.95 10 m., the particles moved
towards the anode and between the cell depth of 4.05 to_2
4.30 10 (m) , the particles moved towards the cathode.
Between the pH values of 5.20 and 4.90, some particles
moved towards the anode, some towards the cathode, and some
in random motion and some virtually at rest (not moving in
any direction) . Since the movement of the particles was
towards both the anode and cathode, there could be the same
number of positive and negative charges and hence this could be the iso-electric point (IEP) (4,10,14,148,149)^
At pH values of 4.9 or less and between the cell depth_2
of 3.70 to 3.95 10 m, the particles moved towards the cathode
(charge reversal) and between the cell depth of 4.05 to 4.30_2
10 m, the particles moved towards the anode (charge reversal),
hence this pH value of 4.9 is known as the zero point of
charge (zpc) which is defined as the pH at which the electro- phoretic mobility of fines is zero^ 4jl °' 148 ' 149 >. The
existence of the zero point of charge thus explains the
reversal of charge.
From these graphs the iso-electric point and the zero
point of charge should coincide. It has been suggested by
-146-
Parks^ 13 , Mular et al^ 1 ' and Hunter^ 4 ' that the observed
zero point of charge should coincide with the iso-electric
point of the solution.
-147-
FIGU
RE.
7.21
,
00
VARI
ATIO
N OF
pH
WIT
H M
OBI
LITY
AT
DEPT
H d =
3-7
0. 1
0 in
)H M 7-0
VO 14 0
TOW
AAN
C jRDS
DE i >TO
WAR
DS
CATH
ODE
v'o2-
0 3-
0 4'-
0 5;
0 .
k
6-
•
PH
4. tfl
7JI
2JL 0
VARI
ATIO
N OF
pH
WIT
H M
OBI
LITY
AT
DE
PTH
d=3-
75.1
0m
TOW
ARDS
AN]
DE
5 r TO
WAR
DS
CATH
ODE
1-0
2-0
3;0
4-0
5-0
L 5•
01" 1
0)
-14
8-
FIGU
RE.?.
25
H 10 Lfi
54 M 0
VARI
ATIO
N O
f BH
WIIH
MOB
ILIT
Y AT
DEP
TH
d=3-
80.
lOfm
TOW AK 4
......
^RDS
CD
E
TOW
ARDS
CA
THOD
E
1-0
z"-0
3-0
<,<)
5-0
JU
6*
PH tfi
M
M
SdL
kQ HI 0
VARI
ATIO
N OF
pH
WIT
H MO
BILIT
Y AT
OFP
TH
d=3-
»5.1
QZ m
..*....*
TOWA
RDS
ANJD
E^
>
TOW
ARDS
CA
THOD
E
1-0
2-0
3-0
(.-0
5-0
. L
6'<60l«1
07]
-14
9-
FIG
UR
E.?.
26
VARI
ATIO
N OF
pH
WIT
H
MO
BIL
ITY
AT
DEPT
H d
= 3-
90.1
()2m
8-0
PH "
7-0
1 ft.
Q
<J1
0 1
5-0 VO ifi z* 0
XHC i
.
W
TOW
ARDS
CATH
ODE
-r
1-0?t
fl 3-
0 VO
5 !
0 h
1, 6
0[x1
07]
VARI
ATIO
N O
FnH
WIT
H M
OBI
LITY
AT
DE
PTH
d=3-
95.1
0m
8-0
PH i
7-0
AJ.
5Ji
ifl
UL 0
Vi
\
TOW
ARDS
CATH
ODE
......
..
l'o
2'-0
S'Q
VO
5-0
/ *•
(-7
-150-
FIG
UR
E. 7
.27
cn
VARI
ATIO
N OF
oH
WIT
H M
OBI
LITY
AT
DEPT
H d=
V05
.102
n>
M IH
Lfl ts. itt M *
•—
TOW
ARD.
SCA
THO
DE
TOW
ARDS
AN
OD
E
rt
M
?0
3-0
VO
5-
0 t
k 6
-0|x
lb'l
VARI
ATIO
N OF
«H
WffH
.MD
KI H
Y A
T H
FPTH
ri
= t-
IO-in2
m
i-JL
1 H M SJL
tfl in. llfi
TOW
ARDS
f* Al
UL
''fff
)DE
*; •
TOW
ARDS
ANOD
E
V'O
2-'0
3:0
4-0
5-0
, 60
[x1f
l' »
A
-151-
FIGU
RE.
7-28
Pr
ta M ta
i S ^ M
. to. vo.
VARI
ATIO
N OF
pH
WIT
H
TOW
ACA
THI i x
TOW
A AN
O
MO
BILI
TY A
T DE
PTH
(U-1
5.10
m
....
..
RDS
IDE
•
r RDS
DE
.....
1?
BJL
M £0_
3J1.
2'Q bO n
VARI
ATIO
N OF
pHW
ITH
MOB
IUTY
AT
DEPT
H fc
wS
lfm
. —
—
......
..
TOW
ARDS
C
/WD
E
TOW
ARDS
AN
ODE
1-0
2-0
3-0
VO
5«0
3-0V-
0 5-
0 /6
-OM
6']/< 'A
-152
-
FlQ
URf
. 7.
29
H k ftQ ro Sffl to ifi M ua 0
VARI
ATIO
N OF
pH
WIT
H
TOW;
CATI
TOW
A
MO
BILI
TY A
T DE
PTH
d=4-
25.1
02in
......
..
......
..
\RDS
10
0E
\f RDS
ANOD
E
M
20
3-0
Co
LJLS
-O
6-01
x10
Pj il
UL
ifl.
tffl.
UL 0
TOW;
CATH j «
TOWA
F AN
C
1-0
2^RDS
OD
Ek f ^D
S OE
......
.
.
0 3-
0 VO
J.
5-0
60[x10
7J
-153-
FI C
URE.
7. 30
PH
to TjO fifl
i en ' 5S » ifl
tfl
......
.
TOW
ARDS
AN
ODE
.....
T tTO
WAR
DS
CATH
ODE
i
pH
ML
H 6J2.
b-0
M id „ A
TOW
ARDS
AN
ODE
j I <r
TOW
ARDS
CA
THOD
E
1-0
203-0
•A5-
0 6-0
(x1-
fl 2-
0VO
>f'•0
60 (*
107)
-154
-
FIG
UR
E. 7
. 31
01 CJl i
PH tfl
12 vo
Jfl
10
M
0
VARI
ATIO
N OF
pH
WIT
H M
OBIL
ITY
AT D
EPTH
d=3
-80.
102m
- CIR
CUIT
REV
ERSF
r
TOWA
R AN
CDS
Of.
TOW
ARDS
CA
THOD
E
1-0
20
3-0
VO
5-0
L
6O
HO
7]
VARI
ATIO
N O
FoH
MO
BILI
TY A
T DE
PTH
d= 3
-85.
102
m -C
IRC
UIT
RE
VERS
ED
\ 7^0
6^ 5JL
irO H 0
TOWA
I AM
I*DS
IDE
TOWA
RTJS
CA
THOD
E
1-0
2-0
3-0
4-0
5«'o
/ 6
OHO7
]
-155-
FIG
UR
E. 7
.32
fVAR
IATI
ON O
F oH
WIT
H M
OBIL
ITY
AT D
EPTH
d=
3-90
.1Q2
m-C
IRCU
IT R
EVER
SED
M JLfl
TOW
ARDS
AN
ODE
en CTl
2-0
TOW
ARDS
CA
THOD
E
2-0
3-0
6 :0|x
107l
5-0 tfl.
Lfl 0 L
Wlf
flO
N O
F pH
WIT
H M
OBIL
ITY
AT D
EPTH
d=
3-95
.10
m-
CIRC
UIT
REVE
RSED
TOW
ARDS
AN
ODE
TOW
ARDS
CA
THOD
E
1-01-0
60 M
o7]
-156-
FIG
UR
E. 7
.33
en
VARW
ION
OF o
H W
ITH
MOB
ILIT
Y AT
DEP
TH d
=V05
. 102|t.-
CIR
CUIT
REV
ERSE
D
)H -UL
24
n
mm
TOW
ARDS
AN
ODE
PH 8-
0
±0.
10 ii 10 n
VARI
ATIO
N OF
pH
MOBI
LITY
AT D
EPTH
d=V
10 ,1
0 m
— C
IRCU
IT R
EVER
SED
^ r-
TOW
iDS
ANOD
E
1-0
2-03-
0 VO
i,
5-0
6-01
x10]
.
——
——
——
* h
VO
2-0
3-0
VO
,5-0
frOt«
107)
-15
7-
FIG
UR
E.
7.31
,
in
co
VARI
ATIO
N O
FpH
WT
HJf
fieiL
IIY A
T D
EPTH
d=
V15.
102m
-CIR
CU
IT
REVE
RSED
H k M in -fcQ sfl vo ifl. M
U
(
TOW/
> CA
T^R
DS
10DE
TOW
ARDS
AN
ODE
I
- -7
1 VO
2^
0 JO
U-
0 J^
5-0
6-
0 MO
l
a-o
L1TY
AT
DEPT
H d=
l-?0
.l82m
-ClR
CU
lT
REVE
RSED
TOW
ARDS
CA
THOD
E
TOW
ARDS
AN
ODE
vo?o
o
-15
8-
FIG
UR
E.7
.35
f H &Q M 6fl
i on UD • 5-
0 kn M M M 0
VARI
ATIO
N O
F DH
WIT
H M
OBI
LITY
AT
DEPT
H d=
(.-2
5.10
m- C
IRC
UIT
REV
ERSE
TOW
* CA
T >RDS
10DE
t
TOWA
F AN
ODOS
1;0
2:0
30
^'0
5:0
6
) oixid7
]
pH tfl
TJi
M iQ M
M
HL
li
0
VA
RIA
TIO
N
OF
pH W
ITH
Mnf
fllY
AT
DFP
TH
ri=
t^n,1
02m
- C
IRC
UIT
.R
EVER
SED
TOW
ARD
S CA
THOD
E
TOW
ARDS
AN
ODE
1-0
2;0
3:0
VO
B;0
6
-159
-
FIG
UR
E. 7
, 36
VARI
ATIO
N OF
pH
WIT
H 2E
TA P
OTEN
TIAL
AT
DEPT
H d=
3-70
.1(?
ii)
VARI
ATIO
N OF
pH
WIT
H ZE
TA P
OTEN
TIAL
AT
d=
3-75
.1(?
n
PH
"tfi
M M
i en ?
5_0
fcfl. H 21 M. 0
TOW
ARDS
AN
IDE
.......
TOW
ARDS
CA
THOD
E
.......
1-0
2-0
3-0
VO
5-0
6;0
7:0
8-0
9J)
10•oi
xio11 ]
PH ; 1
M 15 ita 51 kfl.
M M tl
0
........
TOW
ARD
S AN
ODE
.......
TOW
ARDS
CA
THOD
E
......
.
TO
2;0
j-0
t-0
5-0
6:0
7-0
BO
9 :Q.
1(1
-16
0-
FIG
UR
E.7
, 37
I O1
VARI
ATIO
N O
FpH
WIT
H ZE
TA P
OTEN
TIAL
AT
DEPT
H dQ
-80.
1Q2m
101
7-0
ifl. Vfl.
3-0 1-0
TOW
ARDS
AN
ODE
TOW
ARDS
CA
THOD
E
"To
S
JoM
Jso
fro
K~^ 9-
0 10
'01x1
0
VARI
ATIO
N OF
pH
WIT
H ZE
TA P
OTE
NTI
AL
AT
DEP
TH
d= 3
-85.
pH
7-0 ifi. kfl
M
TOW
ARDS
AN
ODE
TOWA
RDS
CATH
ODE
-i——
——
i——
——
r-11
.1-0
2-
0 3-
0 VO
5-
0 6-
0 7-
0 &0
^9
-0
10-O
IxlO
l
-161-
FIG
UR
E. 7
.38
I en
fcfl
in. M). M
VARI
fllO
N OF
pH
WIT
H ZE
TA P
OTEN
TIAL
AT
DEP
TH
ds3-
90.i(
?m
TOWA
RDS
CATH
ODE
10
20
W)
VO
5-0
6-0
7-0
8-0
* 9-0
10
-01x
10—
——
——
>C,
VARIA
TION
OF PH
WITH
ZET
A POT
ENTIA
L AT
DEPT
H d=
3-95.i
5m
M &JL
M H
TOWA
RDS
ANOD
E
TOWA
RDS
CATH
ODE
1-0
2-0
3-0
4-0
5-0
6-0
7-0
8'0
>0
10-0
1x10
)
-162-
FIGUR
E.7.
39
I CO
PH
7-0 6-0 5JL
2-0
VARI
ATIO
N OF
pHW
ITH
ZETA
POT
ENTI
AL
AT D
EPTH
d=V
05.1
(?m
TOW
ARDS
CA
THOD
E
TOW
ARDS
AN
ODE
1-0
2-0
3-0
VO
5-0
6-0
7-0
«-0
)»9-
0 10
-0>1
0
VARI
ATIO
N O
FpH
WIT
H ZE
TA
POTE
NTIA
L AT
DEP
TH (
U'1
0.
Iff IP
8-0 7-0
ifl.
TCWA
RDS
ANOD
E
1-0
2-0
3;0
ifQ
S'O
6-0
7-0
9-0
9-0
-0^
-163-
FIG
URE.
7.li
O
I w I
4 M t* „
T0\
CAT 4
ms
^
TOWA
RDS
ANOD
E
° to
2-'o
JO
VO
5-0
6*0
7;0
8'
0£9-
'o
1U[x
l611
]
VARI
ATIO
N OF
pH
WIT
H 7E
TA P
OTEN
TIAL
AT
DFPT
H d;
fr-7
D.in
in
fefl.
5-0
TOWA
RDS
ANOD
E
1-0
2-0
3-0
VO
5:0
6:0
7-0
9'0
10-0
Mo1
1 ]
-164
-
FIG
UR
E.
7.41
en
VARK
TION
OF
pH W
ITH
ZETA
PO
TENT
IAL
AT D
EPTH
d^-
25.
PH
7-0 6-0 iQ.
(,•0
1-0
TOW
ARDS
CA
THOD
E
TOW
ARDS
AN
ODE
-111-0
2-0
3-
0 VO
5-
0 6-
0 7-
0 6-
0 f 9
-0
100|
x10
]
VARI
ATIO
N OF
pH
WIT
H ZE
TA P
OTEN
TIAL
AT
DEPT
H d=
PH
6-0 1-0
TOW
ARDS
CA
IHOD
E
TOW
ARDS
AN
ODE
1-0
2-0
3-0
VO
SO
6-0
7-0
6'0
^9Q
10
-0 H
o")
-165
-
FIGU
RE.
7.U2
Bd^
54
VO aa 2-0 0
jt
TOW
ARDS
CA
THOD
E
1-0
2-0
iO
W
5-0
6-0
7-0
8-0 Y
9-0
1(
-11
)-0(x
10 1
VARI
ATIO
N O
FpHW
m T
FTAP
flTFK
lTUI
fiT P
FPTH
ife
MS.
JB-UR
CUIT
PHtt
fi 7-8
ifl
TOW
ARDS
AN ID
E
TOW
ARDS
CA
THOD
E
1-0
2-0
3-0
VO
5-0
6-0
7-0
8-0X
90
10-0
[x
-166-
FIG
URE.
7.1
.3
H
ftfl
Ul 60 54 tfl 20. 0
j
TOW
ARDS
Cf
fHO
DE
10
2-0
30
M)
5-0
6-0
70
8-Q)
. 90
1C
)OM
o"]
p; ift fcfl 30_
2J2
Kl 0
. TOW
ARDS
CA
THOD
E
10
2-0
3'0
W
50
6'0
7-0
JO.
-.9-0
10
1
-167
-
RGUR
E. 7
.
.2 C
IRCU
IT ED
PH
04 ifl
12
i a\ 00
« 4fi
iQ
U> 0
.........
........
TOVW
AN
1
RDS
)OE
t
\
TOW
CA
TARDS
HO
DE
1-b
2-0
>0
VO
5-b
6-'0
7-'0
8:0f
^ 9
:0 1C
PHM If
l
M ia id vo 0
........
TOW
ARDS
AN
, JDE
TOW
RDS
CATH
ODE
TO
2-0
3-0
4-0
5-0
60
7-0
8-0
£ 9
'0
10
-168
-
FIG
UR
E. 7
.
I c£ I
PH
to. to.VA
RIAT
ION
OF p
HWIT
H ZE
TA P
OTEN
TlAl
AT
DEP
TH lU
OS-
102,.
TOW
ARDS
CAT N
ODE
TOW
ARDS
AN
ODE
1-0
2-0
3-0
<*•()
5-0
6-0
7-0
8-0X
9-0
100M
011!
_?
CIRC
UIT
VARI
ATIO
N OF
pH W
ffri Z
ETA
POTE
NTIA
L AT
DEP
W d
^-10
.10>
)-REV
ERSE
D
RH8-
0
10.
1-0
TOW
ARDS
CA
THOD
E
TOW
ARDS
AN
ODE
1-0
2-0
3-0
M>
5'0
6-0
7-0
frO
/9-0
10
0[xio1
1]
-16
9-
FIG
UR
E. 7
.(
-vl
O
y/W
HnO
NO
FoH
WIT
Han
-APn
TFN
TlAl
AT
ITPT
H H
=t.i<
; ir&
_&
&y&
n
H 40 M fca
VO 10.
24.
ML n
C°ATV
i \ TO
Y AN
(
......
.. ......
.....
» k r fARD
S JD
E
, ——
——
——
, ——
——
——
, ——
——
——
, ——
——
——
, ——
——
——
. ——
——
——
. ——
——
——
J
' PH
M la ta
itt iQ 2JL
ML
n
-2
CIRC
UIT
VARI
ATIO
N O
FpH
WIT
H ZE
TA P
OTEN
TIAL
AT
DEPT
H d=
VM
. 10m
-REV
ERSE
D*
...... ...
...
TOW
ARDS
CA
THOD
EI. ^ >
TOW
ARDS
AN
ODE
Ml
2-0
3-0
VO
5-0
6-0
7-0l-O
10
0 W
O
]1-0
2-0
3'0
VO
5-0
6-0
7-0
B-Q
4r,»
0 10
0
-170-
FIG
UR
E.7.
PH
M 2JL 1-0
.0
CIR
CU
IT
VAM
ABON
OFp
H V
fltig
TX
PCT
ENTI
AL A
T DE
PTH
d=V2
5.ld
in-R
EVER
SED
TOW
ARDS
CA
THOD
E
TOWA
RDS
ANO
DE
1-0
20
3-0
U-0
5-0
6-0
7-0
B'-Or
9-0
10-O
HO ]
o
CIRC
UIT
WtlA
TIO
N O
F pH
WIT
H ZE
TA P
OTEN
TIAL
AT
DEPT
H tU
-3Q
.iam
-REV
ERSE
D
pH
Vfij
1-0
TOWA
RDS
CATH
ODE
TOW
ARDS
AN
ODE
?0
?0
VO
5-0
6-0
7-0
8-0/
• 9-
0 10
-0
-171
-
7.5 ELECTROPHORESIS OF COLLIERY WASTE-WATER - H
The graphs of the mobility profiles at different pH
values against the various levels of depth within the
electrophoretic cell using sulphuric acid compared favourably
with those using hydrochloric acid. These graphs can be
seen on Figures 7.48 to 7.54.
The variation of pH with electrophoretic mobility and
zeta potential at the same depth in the electrophoretic
cell also illustrated the same graphical shapes (see Figures
7.55 to 7.78) except that between pH values of 5.3 and 5.0,
the particles moved towards both the anode and cathode whilst
the others were virtually at rest or moving in all directions.
Then at pH values of 5.0 or less the particles at the various
depths within the electrophoretic cell moved in opposite
direction (charge reversal). Hence the iso-electric point
and the zero point of charge were determined to be at pH =
5.0, which agreed favourably with the results obtained in
using hydrochloric acid.
-172-
FIG
UR
E.?.
48
I CO
/I k
MC li, ta 0^ - M 31
»lfl
L
5 3-
6
]
! ! TO
V/ Ahj
3-7
3-8
3-9
4 T
TOW
CATf
ARDS
3D
E
•0 4-1
4-2
4-3
^RDS
10
0E ; '.
i :
i '
• t
4-4
4--2
5MO
J
CIRC
UIT
i ifl
Ifi 0 3
ift
li
ELEC
TROP
H
5 3-
6
IORE
SIS
OF C
OLLIE
RY V
ttSTE
WAT
FR A
T pH
=ML-
RE
i
, !
' i1
' !
>
- 1
'• i TO
WAR
DSAN
t
3-1
3-8
3-9
4 ^
TOWDD
E
0 4'1
4-2
4-
3
ARDS
CATH
ODE 1 1
! .
i•
i :
:;
1
VEB?
>Fn
4-4
4-
-173
-
FIG
URE
.7A
9
Ml
itt 0 3- Ifl
HL M
-7 HO
!
ELEC
ffiOE
5 3-6
HORE
S1S
OF C
OLLI
ERY
WAS
TFW
ATFR
AT
nH=7
-n
: •
;
1
TOWA
P AN
D j
3-7
*8
3'9
4 ^
TOW
CA
T
OS OE
• i
I
•0 V
I V2
>-
3
AROS
MO
DE 1 .
SMO2
]
iL • 12 0 3 10 M
^
iO
WOl
r
flEG
RQEI
> 3'
6
rtORE
SIS
OFCO
LLER
Y W
ASTE
WAT
ER A
T nH
=7-0
- REV
ERSE
TOW
AN
C i
3'7
3-9
3'9
4 ^iVRDS
ID
Ek •0
4-1
1-2
^ V3
rTO
WAR
DS
CATH
ODE
i
•
W
4
-174
-
HGUR
E. 7
. SO
tn i
w67j
i i
ifl
Li
0 3 IA u. 3_i
4^0.
l» 10
fUTT
ROPI
5 3-6
ORES
1S O
F CO
LLIE
RY W
VSTE
WAT
ER A
T pH
=frO
; ;
;
TOW
ARDS
AN
)DE
3-7
3-8
3-9
4.0
4-1
4-2
4-3
^ '
TOW
ARDS
CA
THOD
E
' I
! '
4-4
4--2
4JL
K. > IS.
H.
0 3
ifi.
CIRC
UIT
FiFfTR
npHf
iRfsi
s OF
COIM
ERY
WAST
EWAT
ER A
T rft6
-o-RE
VERS
ED
•5 3-
6
I :
I TOW
AMI
3-7
3-B
3-9
4
ARDS
ID
Eh -0
4-1
4-
2 4-3
1 '
TOW
ARDS
CA
THOD
E : *
:
4-4
4'•5
U10
2 ]
-17
5-
FIG
UR
E.
7.51
°3 Ifl
Lfl
itt ki
FlffT
ROPH
5 36
pRES
C OF
COL
UERY
WAS
TEW
ATFR
AT
nH= M
TOW
3-7
3-8
3-9
V
TOW
CATH
t
——
——
»d
ARDS
OD
E
5 M
O2]
MO7
]
} \
A. iJL 2JL m °3
Ltt
3JL
xib7]
ELEO
BQEJ
5 3'
6
HORE
S1S
OF C
OLLIE
RY W
ASTE
WAT
ER A
T nH
=5-3
- R
TOW
/AN
C A
3-7
3-8
3-9
V
TOV
CATVR
DS> 0
V1
V2
V3
ARDS
HO
OE
VERS
ED
4-4
4'
-176-
FIG
UR
E. 7
.52
MO)
kfi
3_0
li VO 0 3-
H IS.
M071
RFrT
Rnp^
5 3-6
OfiE
SIS
DFCO
LLIE
RY W
ASTE
WAT
ER A
T pH
=5-0
^
. i
' I
1 i
TOVJ A ,
3-7
3-8
3'9
<*ARDS
.O
DEh —
——
——
— I —
——
——
— I —
——
——
— I-
——
TOW
ARDS
CA
THOD
E
'* ,1
i .
i *
•
——
1 ——
——
——
'
V*
V
oft
L
M tfi H 0 3- 1ft
1ft
10 fcft
MO)
CIRCU
1FlF
CTRO
PHnp
Fsis
OF rm
iiFRY
WAS
TFWA
TFR
AT DH
= -O-
REVF
R
i 3-
6
:
j "
ti
TOW
AN
——
— (• —
——
——
— i —
——
——
— I —
——
——
—
3-7
3-8
3'9
4WDS
DDE
——
— i —
——
i ——
— i —
•0
V1
^-2
^^-3
TOW
ARDS
CA
THOD
E
! i
• i
t :
i .
;
i,^
4
,
T SED 5W
02)
-17
7-
oo
FIGU
I Q]
Fi
FTTR
nPHn
oF";!
?; n
prrn
IIFB
V W
ASTF
WAT
FD A
T nH
-t-n
A.
4J) M * VO 0 3-
14 2^0
10 vo' I
*
5 3'
6
i '
:
j 1 '
i
TOW
ARDS
ANOD
Et
i i
i3-7
3-
8 3-
9 4 t
TOW
A
0 4-1
4-
2 4-
3—
——
——
»d
p RDS
CATH
ODE
| •
: :
4-4-
4--2
5MO
]
. 7.5
3CI
RCUI
T j7
EL
ECTR
OPHO
RES1
S OF
COL
UERY
W
ASTE
WAT
ER A
T nH
=4-0
- RE
VERS
ED
ifl
Ht ' to. iQ 10 0 3
UL a ifl 4-0 Sfl
H?l
•5 3-
6
TOV.
ANI
3-7
3-8
39
4
, i
l l
l
ARDS
)D
E
•0 4-
1 4-
2 4-
3 —
——
——
— »d
T P
TOW
ARDS
CA
THOD
E
: ;
t
— i —
——
4-
4 4 •
5 M
O
-178
-
FIG
URE.
?.
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56
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to 3-0 ?-n 1-0 0
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2-
FIG
UR
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56
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3-
FIG
UR
E. 7
. S9
VARI
ATIO
N OF
pH W
ITH
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AT
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PTH
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-15.
ljfm
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VARI
ATIO
N OF
pH
WIT
H M
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4.2
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M
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» M
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4-
FIG
UR
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.60
d= 4
-30.
10 m
PH
ifl
frO
t 00
tn
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M UL 0
N im
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\ TO
V AN
1-0
r ...
....
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S OD
E
2-0
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7 OM
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0
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TOW
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FIG
UR
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61
PH fc
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ifl 10.
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30
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l in M
0
TOW
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IDE
4 k
' y
......
TOW
ARDS
CA
THOD
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1-0
2-0
3-0
VO
5-C»
X)-1
86
-
FIG
UR
E. 7
. 62
VARI
ATIO
N OF
pH
WIT
H M
OBIL
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AT D
EPTH
d=3
-65
-
00
>H M VO kO
M
24
tfl 0
TOW
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RD
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A
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0
TOW
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ARDS
CA
THOD
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1-0
2-0
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4-0
. /,
5'5'
0(x1
0]
-18
7-
FIG
UR
E. 7
.63
OC
CO
H J'C 7-Q
6-0 •i-0 VO
ifl
fcfi 0
^RM
TIO
N O
F pH
WIT
H
MOB
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TY A
T nF
PTH
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CIR
CU
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3.95
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D-
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4 k
TOW
ARDS
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THO
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2:0
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/.
5
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8-
FIG
UR
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6<v
PH 1 k -ao M
60
iD kfl
M 2JL
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VAffl
ATin
N f
lFpH
WTT
H M
OH
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AT
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....
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x10]
PH i I M KL M
.
itt
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TY A
T DE
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EVER
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9-
FIGU
RE.?
. 65
-2
CIRC
UIT
IO
O
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RCUI
T VA
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ION
OF p
H W
ITH
M DE
BIT Y
AT
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H d=
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VERS
ED
iH M M frf
l
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DS
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r
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/
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PH
' tff
l
M ifi kfl
ifl
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0
^ f
TOW
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2-0
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lt-0.
U
5-
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-19
0-
FIG
UR
E.7
.66
VAR
IATI
ON
rfr
M W
ITH
MO
RII
ITY
AT H
FPTM
ri=
t.?<
; m
m_
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te^r
i
PH J k
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5-0
1ft
M ro 0
A \
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1-0
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S
r r^ARD
S OD
E
......
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3-0
<fO
50(
x10]
>
PH ^
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vo.
0
-2
CIRC
UIT
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N OF
PH
WIT
H M
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Y AT
DEP
TH d
=V30
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REV
ERSE
D
TOW
ARDS
C
A'H
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AN
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..
1.0
2-0
*0
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<10]
-19
1-
10 ro
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AnO
NO
FpH
WIT
H7E
TAP
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I AT
DEP
TH
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to vo kfl 14
ift
LH 0
i
TOV
CATir k AR
DS
MODE
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2-0
3-0
i-0
5-0
6-0 ^
7-0
lxiff
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FIG
UR
E.7.
67 VttR
IATT
ttl O
F pH
WIT
H ZE
TAPO
TENT
IAL
ATDE
PIti
(U3-
7S.1(
?in
pH ML)
2-0
TOW
ARDS
CA
THOD
E
0 VO
5-0
6-0-0
-19
2-
FIG
UR
E. 7
.68
ID
CO
\ARU
TTDN
nF
oH W
ITH
7FT
A Pf
lTFM
TIA
I a D
FPTH
ri-X
VLl
ftm
iH 1 IH 6_Q 50 3H
L£>
LQ
0
i \
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X >TO
WAR
DS
CATH
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10
iO
30
io
50
d'o.
)- 70
t-11
10
]
VA
RIA
TIO
N
OF p
H W
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7F
TA P
nTfN
TIA
I A
TflF
PTH
if
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l
pH 10 7_Q
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3J1
2JQ.
TOW
ARDS
CA
THOD
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~I——
——
——
—I—
10
20
30
40
50
60
^y70
80
r-11
-19
3-
FIQ
URE.
7.69
VARI
ATIO
N OF
pH
WIT
H ZE
TA P
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TIAL
AT
DEPT
H d=
3-90
. 1Q
2|n
1? Ifl 6-0
i kO ' 5-
0 0
TOW AN! I
TOV
CAT
1-0
2ARDS [fir
k 7 /ARD
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DE
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VO
5-0
6-0
Y
7-0 l
x—
——
——
——
——
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— h
>
i"91i
H frO •HI
ft& U 3'Q 2-0 1-0 0
VARI
ATIO
N O
FpH
WIT
H7F
TA P
fTTF
hiriA
l AT
DEP
TH
d=3-
95.fO
m
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AN
C ^
TOV
CATAR
DS
DE k y /ARDS
HO
DE
1-0
2-0
3-0
VO
5:0
frO Y
7-0
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-19
4-
I in
pH
M ta ifl.
M
VARI
ATIO
N OF
pH
WIT
H ZE
TA P
OTEN
TIAL
AT
DEPT
H (U
-QS.
JOm
r/ARD
S HO
DF
TOW
ARDS
AN
ODE
-11
FIG
URE.
7.7
0 .VAR
IATIO
N OF
pH
WIT
H ZE
TA P
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TIAL
AT
bEPT
H d=
V1Q
.1fr
iL
PH
ML 5-n
HI
TT3W
RDS
ANOD
E
7-0 M
O11
M)
2'0
3-0
M)
5-0
6-0
Y 7-0
[«IO
] 1-0
?0
3-0
VO
5'Q
6-0
f
7-0 M
O ]
-19
5-
FIG
UR
E. 7
-71
OF p
H W
ITH
ZETA
POT
ENTI
AL A
T DE
PTH
cfcf
c-15
. l8?
n
pH
A
ftQ
1 CTi
5-0
Jfl.
2JL
1j_0 0
M
^ TO
V>
AN
•
m t AR
DS
ODE
1-0
2-0
3'0
VO
5-0
6-0
,. 7-
0 [x
k L-11
10
]
pH
ASL
M ifl H 0
.......
WfSjm
\rTO
WAR
DS
ANOD
E
1-0
2-0
JO
Co
5-0
6'0
j. 7-
0 8-
..
——
kL.
-19
6-
I 10 I
VARI
ATIO
N Q
FpHW
lTHT
FTA
PnTF
NTIA
I AT
HFP
TH
rfal
.7S
.lfi
PH •» Afl
7J1
SSL U) ifi M
TOW
ARDS
CATH
ODE
A TrTO
WAR
DS
ANOD
E
FIG
UR
E. 7
-72
1-0
2-0
3-0
U-0
5-0-^
7-0 !x
VARI
ATIO
N flf
pH W
ITH
7FT
A P
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TIAL
AT
DEPT
H d=
V30
.l"O
ni
M M SJ)
1Q
TOW
ARDS
CA
THOD
EA
TTJW
/«)S
ANOD
E
1-0
2-0
3-0
VO
5-0
6-0
7-
0 [xl
O ]
-19
7-
UD
pH
04 Lfi
M 5-0 vo in ro
-2
CIR
CU
IT
«RIA
T10N
OFp
H W
fTH
ZEtt
POTE
NTIA
L AT
DEP
TH d
=3-7
0.10
m-R
EVER
SED
TOW
ARDS
CA
THOD
E
2-0
3'0
VO
5-0
6-0 /
7-0
[*it
FIG
UR
E.7
.73
-2VA
RIAT
ION
OF p
H W
ITH
ZETA
POT
ENTI
AL A
T DE
PTH
d=3-
75.1
0m-R
EVER
SED
to M M
TOW
ARDS
CA
THOD
E
1'0
2-0
3-0
VO
5-0
6'0
X 7
-0 M
C—
——
——
—>
^
-19
8-
to I
VARI
ATIO
N OF
pH
WIT
H ZE
TA P
OTEN
TIAL
AT
DEPT
H d=
3-eO
.T&
P» Jtfll
fcfl vo ifl
im-R
EVEf
iSEb
o *--
TOW
ARDS
AN
ODE
A VTO
WAR
DS
CATH
ODE
FIG
URE.
7-7
4
1-0
2-0
30
(.-0
50
6-0
>• 7-
0 [x
l11>•
70
>U
'
P. H M
7_Q ta Sifl. (,-n M 10
WIA
TIO
N O
F pH
WIT
H ZE
TA P
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TIAL
AT
DEPT
H d=
3-8S
.1Q
m-
TOW
ARDS
AN
ODE
TOW
ARDS
CA
THOD
E
-111-
0 2'
0 3-
0 VO
5-
0 6-
0 yT
O
8-0
|x10
I"
-19
9-
r>o o o I
iH M.
M 5-0 Jdl
ill kfl
TOW
AN
/
TOV
CAT<\R
DS
3DE
i ARDS
HO
DE
10
20
30
4-0
5-0
6:0
v>
7-0 f«
. ,
...
.», I
o11)
FIG
UR
E.7.
75 VARI
ATIO
N OF
pH W
ITH Z
ETA
POTE
NTIA
LAT
DEP
TH d
=3-9
5.ffl
m- R
EVER
SE
PH ftfl. in.
fcfl i£ 3J1
LQ M
TOW
ARDS
AN
ODE
TOW
ARDS
CA
THOD
E
TO
2-0
3-0
VO
5-0
6-0
v=. T
O 1x1
-200
-
FIG
UR
E. 7
.76.
-2
CIR
CU
ITVA
RIAT
ION
OF tW
WIT
H ZE
TA P
OTE
NTIA
L AT
DEP
TH
d=<r
05. 1
0m-R
EVER
SEI
I J
ro
o
jH &0 3-0 ifl M 0
TOW
CAT
ARDS
HODE
i
•<:>•
TOW
ARDS
AN
ODE
1-0
2-0
3'0
VO
5-0
6'0
^
7-0 (>
N/
) -11
<10
)
vawA
TtnN
OF
nH W
ITH 7
ETA
POTE
NTIA
L AT
DEP
TH t
U 1
0 lO
m-R
EV0«
e
F i» L M 5-0 u>
li H
1-0 0
TOW
CAT i
TOV
AN
ARDS
HO
DE
IARDS
DDE
1-0
2-0
3'0
t-0
5-0
6'0
f
Wl*
l3l
-201-
FIG
UR
E. 7
.77
ro o
ro
VARI
ATIO
N HF
nH
WIT
H TF
T A P
OTFN
T1AI
AT
DEP
TH d
= t.1
5.10
m-R
FWR
<lin
IH ! M.
n
m i ^m \. rTO
WAR
DS
ANOD
E
^^
PH M,
kfl.
M Ifl 0
-2
CIRC
UIT
WRI
ATIO
NOFp
HWIT
H ZE
TA P
OTEN
TIAL
AT
DFPT
M d=
U0.
10m
-RE
V»S
ED
8&
P?
A
TOW
ARDS
AN
ODE
1-0
2'0
3-0
VO
5-0
6-0 /
7-0 H
O ]
1-0
2-0
3-0
lt-0
5-0
' 6-
0-11
M
HO
]
-202-
FIG
UR
E.?
. 78
I IV)
O
CO
WU
AT1
QN
HFp
HW
ITH
ZFT
A PO
TFNT
lAl
AT n
FPTH
pH
'lB-0 ta itt
^>TO
WAR
DS
ANO
DE
1-0
2-0
3-0
4-0
5-0
7-01
x10
-2 CI
RCUI
T W
flATI
ON
DFpH
WIT
H ZE
TA P
OTEN
nAL
AT D
EPTH
d=4
-30.
10 m
- RE
VERS
ED
pH
taj 2JL
TOW
ARDS
CA
TVOD
E
TIM
RD
S AN
ODE
1-0
?-0
3-0
4-0
5-0
6-0
f°
7-0
MO
-203-
7.6 FLOCCULATION OF COLLIERY WASTE-WATER - HC1 and lOOppm
POLYACRYLAMIDE.
I.
2.
BEAKERS
Volume of Sample ml
pH
Amount of Flocculant ml
Optical Q Density
A
200
8.6
20
.243
B
200
7.8
20
0.220
C
200
7.0
20
0.206
D
200
6.0
20
0.187
E
200
4.9
20
0.081
F
200
4.0
20
0.024
G
200
3.0
20
0.009
H
200
2.1
20
0.004
BEAKERS A B C D E F G H
Volume of Sample ml
pH 8.6 7.8 7.0 6.0 4.9 4.0 3.0 2.1
Amount ofFlocculant 100 100 100 100 100 100 100 100ml
0.251 0.226 0.211 0.182 0.072 0.021 0.012 0.007i^ejisx t__y
3. _____________________________________________________ BEAKERS ABCDEFGH
- i-ooo 1000 1000 1000 1000 1000 1000 1000bampie ml
pH 8.6 7.8 7.0 6.0 4.9 4.0 3.0 2.1
Amount ofFlocculant 100 100 100 100 100 100 100 100ml
Density °- 247 0.218 0.203 0.161 0.061 0.028 0.019 0.006
-204-
4. FLOCCULATION OF COLLIERY WASTE-WATER - CYANAMID SUPERFLOC 127
VOLUME OF COLLIERY WASTE-WATER = 200ml
AMOUNT OF FLOCCULANTS ADDED = 2.0ml
pH COMMENTS
1.25 Settled quickly, leaving clear supernatant
2.10 Settled quicKly, leaving clear supernatant
3.00 Settled quickly, leaving clear supernatant
4.95 Settled quickly, leaving clear supernatant
6.70 Supernatant slightly cloudy
8.55 Cloudy suspension.
-205-
FLOCCULATION OF COLLIERY WASTE-WATER
The separation of suspended solids from waste-waters
for purification purposes generally involves primary
treatment by gravity sedimentation, in large clarifiers.
A secondary biological process and/or a. tertiary physico-
chemical process may follow sequentially for waste-water
treatment. The physical process of sedimentation is enhanced
by coagulation and flocculation initiated by chemical agents.
The initially fine and colloidal particles agglomerate into
larger and more dense aggregates which then settle more
rapidly and more completely. Flocculation is the driving
together of colloidal particles by chemical forces, hence
it is the coalescing of coagulated particles into large
particles.Flocculation can be of considerable benefit in
improving continuous filter operations particularly when
very fine size material is present. Flocculant selection is
best done on an experimental basis.
The flocculation of the colliery waste-water was carried
out in the laboratory by the application of subjective visual
criteria to a number of test systems conducted in parallel.
It was also carried out by measuring the optical densities
at the various pH values.
From the determination of the optical densities after
the addition of a polyacrylamide flocculant, the fines were
found to settle quickly at a pH value of 4.9 or less. The
clarity of the waste-water at a pH value of 4.9 or less, was
-206-
seen to be much better than the original waste-water. The
values of the optical densities obtained at pH value of
4.9 were determined to be 66 to 70 per cent of the original
suspension, i.e. this percentage of the fines were flocculated,
Hence at a pH value of 4.9 the colliery waste-water
could now be clarified by flocculation.
It should be noted that at pH values of less than 4.9,
the optical densities were much lower but to obtain these
pH values more acid would have to be added.
-207-
CONCLUSIONS
CHAPTER 8.
-208-
The study of the factors affecting the clarification of
colliery fines was divided into two main areas. The first was
concerned with the characterisation of the fines present in the
suspension. These included particle size and size distribution.
Chemical and mineralogical analyses were carried out by classical
chemical methods and by using X-ray dispersive analysis X-ray powder
crystallography was also applied to several samples and the lattice
spacing (d-spacing) calculated from the Bragg equation. These results
were compared with the ASTM Index and several minerals tentatively
identified.
The density at ambient temperature of the raw colliery waste-
water was found to vary between 972.6 kg/m3 and 1008 kg/m3 ; the
density of suspension obtained after twelve hours of sedimentation
between 950.1 kg/m3 and 989.1 kg/m3 ; and the density of the filtrate
obtained after the filtration of any suspension varied between
940.4 kg/m3 and 993.4 kg/m3 .
The amount of sediment obtained after twelve hours of settling
the decantation of suspension above the sediment was determined to be
between 3.1% and 3.6%.
The raw colliery waste-water was observed to contain fines ( fine
solids) of various sizes and their shapes were irregular. They were
observed to be light to dark-brown and greyish-black and some of the
particles were highly reflecting. In some cases, some of the light
reflecting particles were enclosed in a dark brown or greyish matrix.
The Scanning electron microscope - Steroscan SEM TL 1153-OM was
used to determine the shape of the particles obtained after six hours
of sedimentation. Three different layers were obtained after the six
hours of sedimentation namely:- the sediment; the clayey solution
above the sediment and the suspension above the clayey solution.
209
The results indicated that the fines were of irregular shape,
some plate or tube-like and of a diversity of colour and sizes.
Particle size determination was carried out using the Coulter
Counter Model TA. Several fractions were examined; on a simple
gravity fractionated mixture and after centrifuging and filtration
through Millipore (0.22ym) filters. In general the particle size
distribution was in the range of 3.5 to 92 ym for the coarsest
fraction and 1.24 to 31.5 ym for the finest fraction. The results
were graphed on the particle size distribution charts provided
in the BS 1377:1975. From these results it was concluded that they
consisted of primary clay, fine, medium and course silt and fine
sand.
The elemental analysis was carried out in the first instance
by the application of the Energy Dispersive X-ray Microanalysis
using the equipment - Link Systems 860.
These elements were found to be present on the application of
the Energy Dispersive X-ray Microanalysis procedure: Aluminium (Al),
Silicon (Si), Potassium (K), Calcium (Ca), Titanium (Ti) and Iron(Fe).
The fines were dried, ashed and subjected to chemical analysis
according to BS.1016. The results obtained from this elemental
analysis agreed favourably with those using Energy Dispersive X-Ray
Microanalysis procedure. These substances were found to be present:
Silicon dioxide (Si02 ) Aluminium oxide (A1 203 ), Sodium oxide (Na 20),
Potassium oxide (K20), Iron (III) oxide (Fe203 ), Titanium oxide (Ti02 ).
Manganese oxide (Mn304 ); Phosphorus pentoxide (P 205 h Calcium
oxide (CaO), Magnesium oxide (MgO) and Sulphur ( as Sulphur
trioxide, S03 ). The preferred methods in industry and used in this
investigation for the analysis of oxides of magnesium and sulphur are
210
the atomic absorption spectrophotometry and Eschka's method respectively.
Microanalytical techniques were applied in the analysis of carbon and other elements which could not be analyzed by the Energy Dispersive X-ray equipment.
The total carbon was found to be 9.2%.
The fines were also analysed for organic matter and found to contain Carbon and Hydrogen together with the elements Nitrogen, Chlorine, Sulphur and Phosphorus.
X-ray powder crystallography was applied to the same samples used for particle size distribution (Counter-counter) and the lattice spacing calculated from the Bragg equation. These results were compared with the ASTM Index and the minerals tentatively identified are in Appendix A5.
From the Inorganic Index to the Powder Diffraction File (1969) complied by the Joint Committee on Powder Diffraction Standards, the lattice or d-spacings calculated for the reflections obtained from the X-ray analysis corresponded with those of basic aluminium silicate and aluminium silicate hydroxide. These compounds obtained from the X-ray analysis conform to the elemental analysis ( chemical analysis) and also to the particle size distribution chart - BS 1377;1975 fig.10, which gives clays to be present. Clays are basically aluminium silicates.
On the application of X-ray powder crystallography the fines were analysed to contain Basic Aluminium Silicate (Al 2Si 20 5 (OH) 4 ) and Aluminium Silicate Hydrate (Al 2Si 205 (OH) 4 .2H20). The Literature survey indicated that the clay minerals are essentially hydrous aluminium silicates with magnesium or iron substituting wholly or in
211
part for the aluminium in some minerals and with alkaline or
alkaline earth present as essential constituents in some of them.
Some clays are composed of a single clay mineral, but in many there
is a mixture. In addition to the clay minerals some contain varying
amounts of the so-called non-clay minerals of which quartz, calcite,
fedspar and pyrite are important examples. Also, many clay minerals
contain organic matter and water soluble salts.
The minerals were also analysed using a differential scanning
calorimeter and thermogravimetric system. The presence of the organic
portion prevented any detailed interpretation of the inorganic
constituents.
Two thermal peaks were obtained in each case the first occurring
around 100°C and the second around 450°C to 550°C.
The first peak corresponds to the loss of water and the second
is probably due to the decomposition of organic matter. The presence
of the organic portion present prevented any detailed interpretation
of inorganic constituents present in the colliery fines.
Hence unless the organic fraction can be physically separated
from the rest, unequivocal identification of the minerals would
not be possible. Consequently attempts were made to separate the
coal-inorganic constituents by gravity separations and by use of
heavy liquid density gradients.
There was no separation into distinct zones and bonds and it
was concluded that the samples were a complete mixture of overlapping
sizes and densities.
The second part of the investigation was concerned with the
study of the electrokinetic parameters and flocculation characteristics.
212
Until recently most electrophonetic experiments have involved
cumbersome equipment, tedious microscopic observation and the use
of dark-field illumination.
The mi cro-el ectrophoret ic apparatus which has now been
designed for the measurements of electrophoretic mobility, particle
charge, and zero point of charge and isoelectric point of charge
combines the simplicity of construction with a greatly improved
method of measurement of velocity of the particles and reduction in
contamination of the cell. The images of the particles were projected
onto a television screen and this eliminates the need of tedious
measurement of the velocity of the particles on using a microscope
graticule. It utilizes the ultra-microscope principle of direct
illumination and the light source is placed directly below the
electrophoretic cell.
The electrophoretic mobility of quartz, the zero point of charge
and the iso-electric point were determined using the re-designed
microphoretic apparatus previously described in paragraphs 4.3 and
fig. 9. 2. The quartz particles were found to be negatively charged and
this agreed with the work of Bhappu and Deju ' and also Hunter^ .
The graphs of the mobility profile at different pH values against the
various levels of cell depth within the eledtrophoretic cell compared
favourably with those obtained by Hunter^, Shergold et ar 129 '
and Presad^ '. These graphs can be seen in Figures 7.1 to 7.6.
At a particular cell depth there were obtained different electrophoretic
mobilities of the particles. This could be explained by the fact
that there were different particle size distributions within the
quartz suspension used.
213
The graphs of the mobility profile at the same depth but
against different pH values can be seen in Figures 7.7 to 7.13.
It could be seen on these graphs that between the pH values of
5.6 and 4.0, all the quartz particles moved towards the anode;
between pH 4.0 and 3.8 some moved towards the anode and some
towards the cathode, and at pH values less than 3.8 the particles
moved towards the cathode.
The zero charge was found to be at a pH value of 3.8 which^ ''^compared favourably with previous reported values
The design of the apparatus allows very accurate mobility
measurements and since the lens could be focussed at different
depths within the cell it should enable accurate mobility
measurements of mixtures of different minerals which because of
density differences would settle at a different level within the
cell.
The charges on the fines in the colliery waste-water were
determined to be both positive and negative as can be seen in
the mobility profile at the various pH values against the
different levels of cell depth within the electrophoretic cell.
(Figures 7.14 to 7.23).
On viewing these fines under an optical microscope these
coal particles appeared to be coated, and this was further confirmed
by scanning electron microscopy. They were also found to be
aluminium silicates from x-ray crystallography. The coating on
the coal particles were thought to be a layer of aluminium silicates
which are basically colloidal clay particles, the hydrophilic nature
of which is able to prevent the attachment of an air bubble to
the hydrophobic coal surface.
213A
It would seem unlikely for a clay slime which is negatively
charged to coat the surface of a coal particle carrying quite af 26) high potential of the same sign. However, van Olphen v ' observed
that sub-micro-scopic particles of montmorrilonite clays exist
as thin platelets and from experimental evidence he concluded that
they carry a dual electrical charge. Hence the dual charge on the
fines in colliery waste-water appears to be due to the imperfections
in the silicate crystal lattice structure in which the flat surfaces
are negatively charged whilst the exposure of alumina along the
edges of the platelet is responsible for the positive charge.
It could be possible that the positively charged edges of
the clay particles would be attracted by the negatively charged coal
surfaces so that the clay particles would become oriented
perpendicularly to the surface, and thus being more remote, the
negative charges on the flat clay surfaces exercises less repulsion
and equilibrium may be possible.
Several investigators^ j'^Os' I) nave indicated that positive
sites exist on the edges of clay crystals owing to the exposed
lattice aluminium atoms at the locations. Consequently clay particles
possess two oppositely charged double layers, one associated with
the face of the clay plates and the other associated with the
edges of the plates.
The graphs of the mobility at different pH values on using
hydrochloric acid against the various levels of cell depth compared
favourably with each other with the reversal of charge occurring
at pH value of 4.9.
The graphs of mobility and zeta potential profiles at the same
depth but against the different pH values have been illustrated
In Figures 7.24 to 7.47 using hydrochloric acid.
213B
For pH values between 8.60 and 5.20 and between the cell depth
of 3.75 to 3.95 10~2m., the particles moved towards the anode and_p
between the cell depth of 4.05 to 4.30 10 (m), the particles
moved towards the cathode.
Between the pH values of 5.20 and 4.90, some particles moved
towards the anode, some towards the cathode, and some in random
motion and some virtually at rest ( not moving in any direction).
Since the movement of the particles was towards both the anode and
cathode, there could be the same number of positive and negative
charges and hence this could be the iso-electrical point (lEp} 4 ' 10 ' 14
At pH values of 4.9 or less and between the cell depth of2 3.70 to 3.95 10 m, the particles moved towards the cathode (charge
_o reversal) and between the cell depth of 4.05 to 4.30 10 m, the
particles moved towards the anode ( charge reversal), hence this
pH value of 4.9 is known as the zero point of charge (zpc). The
existence of the zero point of charge thus explains the reversal
of the charge. From these graphs the iso-electric point and the
zero point of charge should coincide.
The graphs of the mobility profiles at different pH values
against the various levels of depth within the electrophoretic
cell using sulphuric acid compared favourably with those using
hydrochloric acid. These graphs can be seen on Figures 7.48 to 7.54.
The variation of pH with electrophoretic mobility and zeta
potential at the same depth in the electrophoretic cell also
illustrated the same graphical shapes ( see Figures 7.55 to 7.78)
except that between pH values of 5.3 and 5.0, the particles moved
towards both the anode and cathode whilst the others were virtually
at rest or moving in all directions. Then at pH values of 5.0 or
213C
less the particles at the various depths within the electrophoretic
cell moved in opposite directions ( charge reversal). Hence the
iso-electric point and the zero point of charge were determined
to be at pH = 5.0, which agreed favourably with the results
obtained on using hydrochloric acid.
The flocculation of the colliery waste-water was carried
out in the laboratory by the application of subjective visual
criteria to a number of test systems conducted together. It was
also carried out by measuring the optical densities at the
various pH values.
From the determination of the optical densities after the
addition of a polyacrylamide flocculant, the fines were found to
settle quickly at a pH value of 4.9 or less. The clarity of
the waste-water at a pH value of 4.9 or less, was seen to be much
better than the original waste-water. The values of the optical
densities obtained at pH value of 4.9 were determined to be 66 to
70 per cent of the original suspension, i.e. this percentage of the
fines were flocculated.
Hence at a pH value of 4.9 the colliery waste-water could
now be clarified by flocculation.
It should be noted that at pH values of less than 4.9, the
optical densities were much lower but to obtain these pH values
more acid would have to be added.
Flocculation was then carried out by varying the pH of
the colliery waste-water. It was found that the flocculation could
be carried out successfully at the zero point of charge of the colliery waste-water.
213D
Time was not available to study the optimum conditions in flocculation .However, now that the zero point of charge,
iso-electric point and the nature of the charges on these fines
have been studied, the quantity of the flocculant and the type
of flocculants could now be studied to determine the optimum
conditions for flocculation.
Handling the raw colliery waste-water should be carried out
with utmost care since E.Coli was detected and it is an organism used as an indicator of faecal contamination and possible presence of pathogendc organisms.
Consequently when the current was switched on to a contaminated sample the movements of the microbes interferred with the
measurements. Thus to eliminate these effects without adding
reagents which might affect the mineral properties the samples showing contamination were aged until no level of microbe activity could be detected.
213E
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93. Slater, R.W. et al. Chemical factors in the flocculation
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94. Black, A.P., et al. The effect of polymer
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95. Derjaguin. B.V., et al. Investigations of forces of
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97. Healey, T.W., et al. The adsorption of aqueous Co(II)
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98. Mackenzie, J.M.W. Zeta-Potential of quartz in the
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99. Mackenzie, J.M.W., and O'Brien, R.T., Zeta-Potential
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103. Alien, L.M., and Matijevic, E., Stability of colloidal
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-228-
APPENDIX A
PYSICO-CHEMICAL PROPERTIES OF COLLIERY WASTE-WATER
-Al-
APPENDIX Al
TABLE 1.1 DENSITIES OF RAW COLLIERY WASTE-WATER, SUSPENSION
AND FILTRATE.
DENSITY OF RAW COLLIERY WASTE -WATER
( KG/M3
983.6
980.2
979.6
972.6
990.8
981.9
1004.0
994.5
996.1
996.9
1007.0
1008.0
MEAN = 991 .3
RELATIVE - 9MEAN 991DEVIATION _
(J
DEVIATION
7.7
11 .1
11.7
18.7
0.5
9.4
12.7
3.2
4.8
5.6
15.7
16.7
MEAN DEVIATION = 9.8
.80 v inn
.3
98%
DENSITY OF SUSPENSION DEVIATIQN
KG/M3
979.9
989.1
985.9
983.0
744.7*
969.7
908.3
927.0
906.4
951 .2
950.1
952.5
MEAN = 955.2
RELATIVE MEAN = DEVIATIQN
24.7
33.9
30.7
27.8
14.5
46.9
28.2
48.8
4.0
5.1
2.7
MEAN DEVIATION = 24.4
24.4 ..955.2 ^ 10°
2 .55%
DENSITY OF FILTRATE
KG/M3
985.3
980.4
993.4
959.3
908.3
984.3
953.7
950.4
940.4
957.5
955.9
954.9
MEAN = 961.1
RELATIVE MEAN DEVIATION
DEVIATION
24.2
19.3
32.3
1 .8
52.8
23.2
7.4
10.7
20.7
3.6
5.2
6.2
MEAN DEVIATION = 17.3
17.3 1nf961.1 X
1 . 80%
LEFT OUT.
-A2-
TABLE 1.2
PERCENTATES OF SOLID FINES IN THE SEDIMENT, CLAYEY SOLUTION, AND SUSPENSION
AMOUNT OF
RAW COLLIERY
WASTE -WATER
(xlO~3
)
791.91
804.19
799.71
805.92
812.83
801.54
803.21
795.63
796.87
794.48
805.88
800.67
AMOUNT OF
SEDIMENT
AFTER
SEDIMENT
ATION
(kg)
(xlo~3)
26.15
26.13
27.79
26.42
26.18
28.82
25.46
24.98
24.82
25.02
25.64
25.97
AMOUNT OF
SOLID FINES
IN THE CLAYEY
SUSPENSION
(kg)
(x!0~3
)
0.6295
0.6325
0.6253
0.7810
0.6071
0.6309
0.6509
0.6355
0.6669
0.5674
0.6580
0.6515
AMOUNT OF
SOLID FINES
IN SUSPEN
SION (kg)
do-3)
0.1739
0.1719
0.1718
0.2013
0.1868
0.1705
0.1731
0.1655
0.1755
0.1640
0.1838
0.1830
PERCENTAGE
OF SEDIMENT
IN COLLIERY
WASTE -WATER
3.30
3.25
3.47
3.28
3.22
3.60
3.17
3.14
3.11
3.15
3.18
3.24
PERCENTAGE OF
SOLIDS IN CLAYEY
SUSPENSION IN
COLLIERY
WASTE -WATER
0.0795
0.0787
0.0782
0.0969
0.0749
0.0787
0.8104
0.0799
0.0837
0.0714
0.0816
0.0814
PERCENTAGE OF
SOLID FINES IN
SUSPENSION IN
COLLIERY
WASTE-WATER
0.0220
0.0215
0.0215
0.0249
0.0230
0.0213
0.0216
0.0208
0.0220
0.0206
0.0228
0.0229
-A3-
APPENDIX A2
PHOTOGRAPHS OBTAINED BY THE APPLICATION OF SCANNING ELECTRON
MICROSCOPY (S.E.M.)
-A4-
-A5-
-Z.V-
-A9-
o
APPENDIX A3
RESULTS OBTAINED USING THE COULTER COUNTER EQUIPMENT MODEL TA,
TABLE 3.1 SAMPLE A (1)
PARTICLE SIZE RANGE PERCENTAGE - MICRONS (urn) FREQUENCY
' DISTRIBUTION
less than 3.55
3.55 -
4.52 -
5.64 -
7.18 -
9.00 -
11.20 -
14.20 -
18.00 -
22.50 -
28.50 -
36.00 -
45.50 -
57.50 -
72.00 -
Samples
4.52
5.64
7.18
9.00
11.20
14.20
18.00
22.50
28.50
36.00
45.50
57.50
72.00
91.00
A(l) and A(2)
0.80
5.60
4.00
6.00
5.50
5.90
6.20
8.00
9.00
11.80
11 .70
10.50
8.00
4.40
2.60
CUMULATIVE PERCENTAGE FREQUENCY
100.00
99.20
93.60
89.90
83.60
78.10
72.20
66.00
58.00
49.00
37.20
25.50
15.00
7.00
2 .60
This is the particle size distribution for the particles
which formed the sediment obtained from gravity settling.
-All-
TABLE 3.2 - SAMPLE A (2)
PARTICLE SIZE RANGE PERCENTAGE -MICRONS- (yum) FREQUENCY
DISTRIBUTION
less than 3.60
3.60 -
4.60 -
5.75 -
7.30 -
9.10 -
11.50 -
14.50 -
18.30 -
22.80 -
29.00 -
36.50 -
45.60 -
58.00 -
73.00 -
4.60
5.75
7.30
9.10
11.50
14.50
18.30
22.80
29.00
36.50
45.60
58.00
73.00
91 .00
0.20
5.80
3.80
6.00
5.30
5.80
6.30
8.30
8.90
11 .90
11 .90
10.50
8.00
4.40
2.60
CUMULATIVE PERCENTAGE DISTRIBUTION
100.00
99.80
94.00
90.20
84.20
78,60
72.80
66.50
58.20
49.30
37.40
25.00
15.00
7.00
2 .60
-A12-
TABLE 3.3 - SAMPLE B(1)
PARTICLE SIZE RANGE PERCENTAGE -MICRONS- (/Um) FREQUENCY
DISTRIBUTION
less than 3.65
3.65 -
4.60 -
5.80 -
7.30 -
9.20 -
11 .60 -
14.60 -
18.50 -
23.40 -
29.00 -
36.50 -
45.50 -
57.80 -
73.00 -
Samples
4.60
5.80
7.30
9.20
11.60
14.60
18.50
23.40
29.00
36.50
45.50
57.80
73.00
91 .00
B ( 1 ) and B ( 2 )
0.20
10.10
8.20
12.50
11 .20
10.10
9.10
9.60
9.00
7.20
6.00
3.80
1 .40
0.60
0.80
CUMULATIVE PERCENTAGE FREQUENCY
100.00
99.80
89.70
81 .50
69.00
57.80
47.70
38.60
29.00
20.00
12 .80
6.80
3.00
1 .40
0.80
This is the particle size distribution for the
particles which formed the clayey solution just above the
sediment obtained from the gravity sedimentation.
-A13-
TABLE 3.4 - SAMPLE B (2)
PARTICLE SIZE RANGE -MIC RONS -(^Lim)
less than 3.60
3.60 -
4.55 -
5.75 -
7.25 -
9.10 -
11.50 -
14.50 -
18.20 -
22.50 -
28.50 -
36.00 -
45.50 -
57.00 -
73.00 -
4.55
5.75
7.25
9.10
11 .50
14.50
18.20
22.50
28.50
36.00
45.50
57.00
73.00
91.00
PERCENTAGE FREQUENCY DISTRIBUTION
0.10
10.30
8.10
12.50
11.40
10.10
9.00
9.60
9.10
7.30
6.00
3.70
1.80
0.50
0.50
CUMULATIVE PERCENTAGE FREQUENCY
100.00
99.90
89.60
81 .50
69.00
57.60
47.50
38.50
28.90
19.80
12.50
6.50
2.80
1.00
0.50
-A14-
TABLE 3.5 - SAMPLE C(l)
PARTICLE SIZE RANGE -MICRONS- (jum)
less than 1 .24
1.24 -
1.55 -
1.95 -
2.45 -
3.10 -
3.90 -
4.95 -
6.20 -
7.90 -
9.80 -
12.40 -
15.60 -
19.60 -
24.50 -
1.55
1.95
2.45
3.10
3.90
4.95
6.20
7.90
9.80
12.40
15.60
19.60
24.50
31.50
PERCENTAGE CUMULATIVE FREQUENCY PERCENTAGE DISTRIBUTION FREQUENCY
0.50
14.00
11 .00
16.00
13.00
10.00
7.50
5.00
4.50
3.50
3.00
2.00
1 .50
3.00
5.50
100.00
99.50
85.00
74.50
58.50
45.50
35.50
28.00
23.00
18.50
15.00
12 .00
10.00
8.50
5.50
Samples C(l) and C(2)
This is the particle size distribution for the
fines in suspension after the sedimentation process and
this was obtained by vacuum filtration using Millipore
filters (size 0.22 urn).
-A15-
TABLE 3.6 - SAMPLE C (2)
PARTICLE SIZE RANGE -MICRONS- (jUm)
less than
1
1
1
2
3
3
5
6
7
10
12
15
19
25
.25 -
.57 -
.98 -
.50 -
.10 -
.95 -
.00 -
.25 -
.90 -
.00 -
.;50 -
.80 -
.80 -
.00 -
1
1
2
3
3
5
6
7
10
12
15
19
25
31
1 .25
.57
.98
.50
.10
.95
.00
.25
.90
.00
.50
.80
.80
.00
.50
PERCENTAGE FREQUENCY DISTRIBUTION
0
14
11
16
13
10
7
5
4
3
2
2
1
3
5
.50
.00
.00
.00
.00
.00
.50
.00
.50
.50
.70
.30
.50
.00
.50
CUMULATIVE PERCENTAGE FREQUENCY
100
99
85
74
58
45
35
28
23
18
15
12
10
8
5
.00
.50
.50
.50
.50
.50
.50
.00
.00
.50
.00
.30
.00
.50
.50
-A16-
TABLE 3.7 - SAMPLE D (1)
PARTICLE SIZE RANGE PERCENTAGE -MICRON- (urn) FREQUENCY
DISTRIBUTION
less than 1.24
1.24 -
1.55 -
1.95 -
2.45 -
3.10 -
3.90 -
4.95 -
6.20 -
7.80 -
10.00 -
12.50 -
15.50 -
19.50 -
25.00 -
Samples
1 .55
1.95
2.45
3.10
3.90
4.95
6.20
7.80
10.00
12.50
15.50
19.50
25.00
31 .50
D ( 1 ) and D ( 2 )
0.20
4.30
3.50
7.50
7.70
8.60
7.20
8 .80
8.70
9.00
8.30
6.20
8.20
7.30
4.50
CUMULATIVE PERCENTAGE FREQUENCY
100.00
99.80
95.50
92.00
84.50
76.80
68.20
61 .00
52.20
43.50
34.50
26.20
20.00
11 .80
4.50
This is the particle size distribution for the fines
in suspension after the sedimentation process and this
was obtained by centrifugation using Heraeus Christ
GMBH Osterode/Harz Piccolo Centrifuge No. 38836.
-A17-
TABLE 3.8 - SAMPLE D (2)
PARTICLE SIZE RANGE -MICRONS- (yum)
less than 1 .24
1.24 -
1.55 -
1.95 -
2.50 -
3.10 -
3.90 -
4.90 -
6.30 -
7.80 -
9.80 -
12.50 -
15.50 -
19.50 -
24.50 -
1.55
1.95
2.50
3.10
3.90
4.90
6.30
7.80
9.80
12.50
15.50
19.50
24 50
31.00
PERCENTAGE FREQUENCY DISTRIBUTION
0.10
4.40
3.50
7.80
7.70
8.50
8.00
8.50
8.50
9.00
8.20
6.20
8.00
7.20
4.40
CUMULATIVE PERCENTAGE FREQUENCY
100.00
99.90
95.50
92.00
84.20
76.50
68.00
60.00
51.50
43.00
34.00
25.80
19.60
11 .60
4.40
-A18-
APPENDIX A4
RESULTS OF THE CHEMICAL ANALYSIS OF THE COLLIERY WASTE-WATER
TABLE 4.1 ENERGY DISPERSIVE X-RAY ANALYZER
LINK SYSTEMS 860
SAMPLES
A
B
C
D
Al
Al
Al
Al
E L E M
Si
Si
Si
si
E N T S
K
K
K
K
Ca
Ca
Ca
Ca
Ti
Ti
Ti
Ti
Fe
Fe
Fe
Fe
TABLE 4.1 B.S. 1016 (75.8% ASH) RAW MATERIAL EVAPORATED
AT 50°C FOLLOWED BY DRYING IN VACUUM AT 50°C
AND OVER PHOSPHORUS PENTOXIDE IN DESICCATOR AND ASHED
COMPOUND
SiO2
A "1 (~\ii-L f\ \J n
Na2°
K2°
Fe2°3
TiO2
Mn3°4
P2°5
CaO
MgO
so 3
PERCENTAGE (%)
52.60
29.10
0.53
3.40
3.25
1 .33
0.04
0.90
2.57
1 .80
0.20
-A19-
TABLE 4.3 MICROANALYSIS OF TOTAL SEDIMENT
ELEMENT
CARBON
HYDROGEN
NITROGEN
CHLORINE
SULPHUR
PHOSPHORUS
1
9.44%
1 .37%
0.16%
0.40%
0.27%
0.85%
2
9.00%
1 .34%
0.17%
0.43%
0.32%
0.70%
TABLE 4.4 B.S.. 1016 - GRAVIMETRIC ANALYSIS
OF TOTAL SEDIMENT
COMPOUND
MINERAL CARBONATES
INORGANIC CARBON
1
2.39%
0.48%
2
2.07%
0.41%
-A20-
APPENDIX A5
TABLE 5.1 RESULTS OBTAINED FROM X-RAY MEASUREMENTS
ON SAMPLES A, B, C, AND D.
SUBSTANCE FORMULA d(A) d(A) d(A)
Basic Aluminium Silicate Al 2 Si2 O 5 (OH) 4 1.48 2.33 4.34
Basic Aluminium Silicate Al 9 Si9 O t-(OH) A -,-,,- -. co -> ->-,^ ZD *± / • j_ o j • DO ^ • 33
Jv
Basic Aluminium Silicate Al2 Si 205 (OH) 4 3.58 7 -15g 2.32
Aluminium Silicate Hydrate Al 2Si2O5 (OH) 4 3.58 7.18 1.49
. 2H2 0
Aluminium Silicate Hydrate Al 9 Si 9 O t-(OH) A 4.41 7.40 0 4.37^^-54 x y /
-A21-
APPENDIX B.
ELECTROPHORESIS OF IQQppm QUARTZ SUSPENSION USING HC1
-A22-
TABLE B.I ELECTROPHORESIS OF lOOppm QUARTZ SUSPENSION AT pH = 5.2
CONDUCTIVITY (X) = 3 . 92 .1 (Tahiti" 1 .rrf 1CROSS-SECTIONAL AREA OF THE _ -4 2 ELECTROPHORETIC CELL(A) ~ i ' Ut 10 - m
DISTANCE TRAVELLED BY THEPARTICLES ON THE TELEVISION = 14.0.10 m.SCREEN (X)
MIGRATION TOWARDS
d(m) 3.70V(volt)60.78I (amp)R(ohm)Km)E(volt m-1)
62.219.773.83
15.87
17.818.018.217.617.417.817.618.018.017.618.218.218.418.418.018.0
3.8060.8162.249.773.83
15.88
17.216.816.616.417.016.216.616.217.016.416.417.017.216.616.816.8
3.9060.8062.239.773.83
15.88
15.215.415.816.016.015.615.615.816.015.215.215.615.415.815.415.0
TIME (SEC) TAKEN TO
THE POSITIVE
4.0060.8262.249.773.83
15.88
14.614.415.015.014.214.814.214.615.014.014.214.014.414.814.614.0
TRAVEL
46062
93
15
14151515161515151516151515161515
ELECTRODE
.10
.81
.24
.77
.83
.88
.8
.2
.0
.6
.0
.8
.4
.2
.4
.0
.2
.8
.0
.0
.6
.6
THE DISTANCE
4.60.62.9.3.
15.
16.16.17.17.16.16.16.16.16.16.16.17.16.16.16.16.
ON
2083267783
88
26004
62842806468
THE
46062
93
15
16171716161717171716161717171717
.30
.79
.22
.77
.83
.87
.4
.0
.2
.8
.8
.4
.6
.2
.4
.6
.8
.2
.4
.0
.6
.6
xlO 2
xlO~ 6xlO 5xlO~2
xlO2
TELEVEISION SCREEN
-A23-
TABLE B.2 ELECTROPHORESIS OF lOOppm QUARTZ SUSPENSION AT pH = 5.2
CONDUCTIVITY^CROSS-SECTION AREA OF THE ELECTROPHORETIC CELL (A)
DISTANCE TRAVELLED BY THE PARTICLES ON THE TELEVISION SCREEN (X)
CIRCUIT REVERSED
= 3.92.10 4ohm.~ 1 m~ 1
= 1 .0. 10~4 m2
= 14.0.10~2m.
MIGRATION TOWARDS THE POSITIVE ELECTRODE
d(m) 3.70V(volt)60.82I ( amp )R(ohm)Km)E(voltm" 1 )
62.249.773.83
15.88
17.617.817.418.018.618.418.218.018.417.618.217.418.018.418.218.0
TIME (
3.8060.7862.219.773.83
15.87
16.816.617.217.016.617.416.817.417.617.217.017.417.217.617.417.0
3.9060.8062.239.773.83
15.88
15.816.216.416.015.616.016.216.616.215.615.816.416.616.216.416.0
SEC) TAKEN TO
46062
93
15
14141515141415151415141515151414
.00
.81
.24
.77
.83
.87
.6
.4
.0
.4
.8
.4
.2
.4
.8
.0
.6
.4
.2
.0
.8
.4
TRAVEL
46062
93
15
15151616161516161616151615161615
.10
.82
.24
.77
.83
.88
.4
.8
.2
.8
.0
.6
.4
.6
.0
.2
.4
.8
.6
.4
.6
.8
THE DISTANCE
4.60.62.9.3.
15.
16.16.16.17.17.16.17.16.16.17.16.16.16.16.16.16.
ON
2079227783
87
4282260680462426
THE
4.3060.8362.269.773.83
15.88
17.217.417.818.218.017.217.617.217.817.618.017.218.218.017.417.8
xlO~ 2
xlO~ 6xlO 5xlO~2
xlO2
TELEVISION SCREEN
-A24-
TABLE B.3 ELECTROPHORESIS OF lOOppm QUARTZ SUSPENSION AT pH = 4.5
CONDUCTIVITY (X)CROSS-SECTIONAL AREA OF THE ELECTROPHORETIC CELL (A)DISTANCE TRAVELLED BY THE PARTICLES ON THE TELEVISION SCREEN (X)
=16.0 10" 4ohm~ 1 m~ 1
= 1.0 10~ 4 m2
= 14.0 10~2 m
MIGRATION TOWARDS THE POSITIVE ELECTRODE
d(m) 3.70V(volt)58.06I ( amp )R(ohm)Km)E(volt m-1)
241.92.403.84
15.12
16.216.416.016.215.816.416.015.816.616.016.416.215.816.016.415.8
TIME (
3.8058.06
241.92.403.84
15.12
15.215.615.816.015.015.015.415.815.615.015.415.215.815.016.015.4
3.58.
242.2.
3.
15.
14.14.14.14.
15.14.14.14.
15.14.
15.14.
14.14.
14.
14.
SEC) TAKEN
90
10
04084
13
2
684
042
8
04
082
42
6
TO
4.00
58.08242.0
2.40
3.84
15.13
13.2
13.013.614.014.213.8
13.213.4
13.413.8
14.0
13.613.4
14.2
13.013.4
TRAVEL
458
241
23
15
1314141414141314
1314
13131414
1414
.10
.05
.8
.40
.84
.11
.8
.2
.6
.0
.4
.6
.8
.0
.6
.0
.6
.8
.2
.4
.2
.4
4.58.
241 .
2.3.
15.
14.15.14.15.15.14.15.15.
15.15.14.14.15.15.14.15.
THE DISTANCE ON
20
069
4084
12
628
0466042
68
04
82
THE
458
241
23
15
1516161516151616151516161516
1515
.30 xlO~
.07
. 9 xlO~
.40 xlO 5
.84 xlO~
.12 xlO2
.4
.2
.0
.6
.0
.8
.4
.0
.6
.4
.0
.4
.8
.0
.8
.6
TELEVISION SCREEN
-A25-
TABLE B.4 ELECTROPHORESIS OF lOOppm QUARTZ SUSPENSION AT pH = 4.5
CONDUCTIVITYCROSS-SECTION AREA OF THE ELECTROPHORETIC CELL (A)DISTANCE TRAVELLED BY THE PARTICLES ON THE TELEVISION SCREEN (X)
CIRCUIT REVERSED
= 16.0 10~ 4 ohm' 1 nf 1
= 1 .0 10~ 4 m2
= 14.0 10~ 2 m
MIGRATION TOWARDS THE POSITIVE ELECTRODE
d(m) 3.70V(volt)58.10I(amp)242.0R(ohm)Km)E(volt m- 1 )
2.403.84
15.13
16.416.616.816.016.616.216.015.815.615.816.215.616.015.416.816.0
TIME (
3.8058.09
241.92.403.84
15.12
15.216.016.215.615.415.815.215.616.015.815.615.015.215.416.216.0
3.9058.10
242.02.403.84
15.13
14.214.614.815.215.415.014.815.214.414.815.414.415.215.014.615.0
SEC) TAKEN TO
4.0058.07
241.92.403.84
15.12
13.413.814.014.213.613.214.013.613.013.413.214.013.613.014.213.4
TRAVEL
458
24123
15
14141515141415141415141415151414
.10
.09
.9
.40
.84
.12
.4
.8
.2
.0
.6
.8
.0
.4
.6
.2
.6
.8
.0
.2
.4
.4
4.58.
242.2.3.
15.
15.15.15.16.16.15.16.15.15.15.15.15.14.15.15.15.
THE DISTANCE ON
200804084
13
6420280640402488
THE
458
24223
15
16161516151616161615151616151616
.30
.10
.0
.40
.84
.13
.4
.2
.8
.0
.6
.4
.6
.4
.0
.8
.6
.4
.0
.8
.0
.2
xlO 2
xlO~ 6xlO 5xlO~ 2
xlO2
TELEVISION SCREEN
-A26-
TABLE B.5 ELECTROPHORESIS OF lOOppm QUARTZ SUSPENSION AT pH = 4.0
CONDUCTIVITY (X) =54.0 lOCROSS-SECTIONAL AREA OF THE ELECTROPHORETIC CELL (A)DISTANCE TRAVELLED BY THE PARTICLES ON THE TELEVISION SCREEN (X)
MIGRATION
d(m) 3.70V( volt) 58. 20 I(amp)816.4 R(ohm) 7.129 l(m) 3.85E(volt 15.12
15.215.014.815.414.614.815.215.414.615.214.615.015.214.815.014.8
3.8058.21
816.6 7.128 3.85
15.12
14.614.814.414.214.814.014.614.414.214.014.214.614.014.814.814.2
-, n , n -4 2 = 1.010 m
= 14.0 10~ 2m
TOWARDS THE POSITIVE ELECTRODE
3.90 458.22 58
816.8 817 7.128 7 3.85 3
15.13
13.814.013.213.013.813.413.213.613.013.414.013.613.413.013.813.2
TIME (SEC) TAKEN TO
15
12131312121213121212121312121312
.00
.24
.0
.129
.85
.13
.8
.2
.0
.6
.4
.0
.0
.4
.2
.6
.8
.0
.2
.6
.2
.0
4
58 816
7 3
15
13131413131313141313131413131313
.10
.20
.4
.129
.85
.12
.2
.8
.2
.6
.4
.0
.6
.0
.6
.0
.2
.0
.8
.4
.6
.2
4.58.
816. 7. 3.
15.
14.13.14.14.14.14.14.14.14.14.
13.14.14.14.14.14.
TRAVEL THE DISTANCE ON
2023 9128 85
13
0826084642808624
THE
4.3058.21
816.6 7.129 3.85
15.12
14.615.215.014.815.215.414.614.815.415.015.414.815.015.215.214.6
xlO 2
xlO~ 6 xlO4 xlO~ 2
xlO2
TELEVEISION SCREEN
-A27-
TABLE B.6 ELECTROPHORESIS OF lOOppm QUARTZ SUSPENSION AT pH = 4.0
CONDUCTIVITY (X) =54.0 10~4 ohm" 1 nf 1CROSS-SECTIONAL AREA OF THE _ -4 2 ELECTROPHORETIC CELL (A) - 1.0 10 m
DISTANCE TRAVELLED BY THE _ -2 TELEVISION SCREEN (X) -14.010 m
CIRCUIT REVERSED
MIGRATION
d(m) 3.70V( volt) 58. 24I ( amp )R(ohm)Km)E(volt M" 1 )
817.0
3.58.
816.7.129 7.3.85
15.13
14.614.414.215.014.814.615.214.415.214.814.414.815.014.214.614.8
TIME (
3.
15.
14.14.14.13.14.14.14.14.14.14.14.14.14.14.14.14.
8019312985
12
6028048204226868
TOWARDS THE POSITIVE ELECTRODE
3.9058.22
816.87.1283.85
15.13
13.213.614.013.813.613.214.213.413.813.413.214.013.413.613.414.2
458
81673
15
12121312121212121212121212131212
.00
.18
.2
.128
.85
.11
.4
.8
.0
.4
.8
.6
.2
.4
.0
.2
.0
.4
.6
.0
.8
.0
SEC) TAKEN TO TRAVEL THETELEVISION
458
8167
3
15
13131314131313141313131314131413
.10
.19
.3
.129
.85
.12
.4
.2
.8
.0
.6
.0
.8
.0
.6
.8
.4
.0
.0
.6
.0
.8
DISTANCE
458
8167
3
15
14141515141514141514141414141414
ON
.20
.21
.6
.128
.85
.12
.2
.6
.0
.0
.8
.2
.4
.6
.0
.2
.8
.4
.2
.6
.8
.4
THE
4.30 xlO 258.23
816.9 xlO~ 67.128 xlO 43.85 10~ 2
15.13 102
14.615.215.015.415.614.815.015.415.214.814.615.015.615.215.615.4
SCREEN
-A28-
TABLE B.7 ELECTROPHORESIS OF lOOppm QUARTZ SUSPENSION AT pH = 3.8
-4 -1 -1 CONDUCTIVITY (X) = 94.0 10 ohm m
CROSS-SECTIONAL AREA OF THE _ -4 2 ELECTROPHORETIC CELL (A) ~
DISTANCE TRAVELLED BY THE PARTICLES -, a n -, n~2 ON THE TELEVISION SCREEN ( X) ~
MIGRATION
d(m)
V(volt)
I { amp ) R(ohm)
Km)E(volt m r )
3.70 58.31
1 .424 4.10
3.85
15.15
13.4
13.0
13.6
13.4
14.0
13.2
13.6
13.8
13.6
13.2
13.8
13.013.2
13.0
14.0
13.4
3.80 58.28
1.422 4.10
3.85
15.12
12.8
12.612.4
12.212.8
13.012.0
12.4
12.0
12 .812.6
12.0
13.012.4
12.8
12.6
TOWARDS THE NEGATIVE ELECTRODE
3.
58.
1 . 4.
3.
15.
12.
12.
11 .
11 .11 .
12.
11 .
11.
11 .12.
11 .
11.11 .
11 .
11.
11 .
TIME (SEC) TAKEN
90
29
423 10
85
14
2
06
48
22
4
8
042
6
4
6
8
4
58
1 4
3
15
10
1011
1110
1110
10
10
10
1110
10
10
10
10
.00
.30
.424
.10
.85
.15
.6
.8
.2
.0
.4
.2
.2
.0
.4
.8
.0
.6
.2
.4
.0
.0
TO TRAVEL THE
4
58
1 4
3
15
11
11
11
11
11
11
11
11
11
11
11
11
11
11
11
11
.10
.28
.422
.10
.85
.12
.0
.4
.6
.0
.8
.4
.2
.6
.4
.0
.8
.2
.6
.4
.2
.4
DISTANCE
4. 58.
1 . 4.
3.
15.
12.
12.
12.
12.12.
12.
13.12.12.
12.
12.
12.
12.
12.
12.
12.
ON
20
29
423
10
85
14
6
04
82
2
0
68
8
4
02
06
4
THE
4.30 xlO 2 58.31 1.424 xlO~ 3 4.10 xlO4
3.85 10~ 2
15.15 102
13.6
13.012 .8
13.4
13.6
13.2
14.0
14.0
13.8
14.2
13.4
13.2
14.2
12.8
13.0
13.6
TELEVISION SCREEN
-A29-
TABLE B.8 ELECTROPHORESIS OF lOOppm QUARTZ SUSPENSION AT pH = 3.8
CONDUCTIVITY (X) =94.0 10~ 4 ohm" 1 m" 1
CROSS-SECTIONAL AREA OF THE _ , o , n ~4 2 ELECTROPHORETIC CELL (A) i.u.iu m
DISTANCE TRAVELLED BY THE _ 2 PARTICLES ON THE TELEVISION = 14.0 10 m SCREEN (X)
CIRCUIT REVERSED
MIGRATION TOWARDS THE
d(m)
V(volt)
I ( amp )R(ohm)Km)E(voltm-1)
3.70
58.261.422
4.10
3.86
15.11
13.6
14.4
14.2
13.8
13.4
13.0
14.0
13.2
13.4
13.2
13.0
14.4
13.8
13.614.2
14.0
TIME (
3.80
58.271.42
4.10
3.86
15.11
12.0
13.013.4
12.8
13.2
13.0
12 .612.4
13.2
12.6
12.4
12.0
13.4
12.8
12.0
12.6
3.90
58.251.422
4.10
3.86
15.11
11 .4
11 .812.0
11 .612.4
12.0
11.6
11.411.2
11.8
12.0
11 .4
11 .8
11 .612.4
11.8
SEC) TAKEN TO
4.
58.
1.
4.
3.
15.
10.
10.
11 .
10.
10.
10.
10.
10.
10.
10.
10.
10.
10.
10.10.
10.
0026422
1086
11
4
8
02
02
04
6
8
62
0
04
2
TRAVEL
NEGATIVE ELECTRODE
4
58
1
4
3
15
11
11
11
11
11
11
11
11
11
1112
1112
11
11
11
.10
.27
.422
.10
.86
.11
.0
.2
.6
.0
.8
.4
.6
.4
.2
.8
.0
.4
.0
.0
.4
.2
THE DISTANCE
4.
58.
1 .
4.
3.
15.
12.
12.
12.
12.
13.
13.12.
13.
13.12.
12.
12.
12.
12.
12.
12.
ON
20
28422
1085
13
4
62
02
08
00
68
4
4
62
8
THE
4.30
58.281 .422
4.10
3.85
15.13
12.8
13.2
13.8
13.614.0
13.4
13.2
12.8
13.0
13.0
13.6
13.4
13.8
14.013.2
13.2
xlO 2
xlO~ 3
xlO4
xlO~2
xlO2
TELEVISION SCREEN
-A30-
TABLE B.9 ELECTROPHORESIS OF lOOppm QUARTZ SUSPENSION AT pH = 3.5
CONDUCTIVITY (X) = 240.0 10~4 ohm" 1 m" 1
CROSS-SECTIONAL AREA OF THE _ , n -, o~4 2 ELECTROPHORETIC CELL (A) ~
DISTANCE TRAVELLED BY THE _2 PARTICLES ON THE TELEVISION = 14.0 10 m SCREEN (X)
MIGRATION
d(m)
V(volt)
I ( amp )
R(ohm) Km)
E(volt m-1)
3.70
54.51
3.40
1 .603 3.85
14.17
12.4
12.0
12.2
12.0
12.612.2
12.4
12.8
12.0
12.2
12.8
12.6
12.8
12.4
12.0
12.4
TIME (
3.80
54.48
3.40
1 .602 3.85
14.16
11 .2
11 .6
11 .8
11.4
11 .012.0
11 .8
11 .2
11 .4
11 .6
12.0
11 .2
11 .011.4
11 .6
11.8
TOWARDS THE NEGATIVE ELECTRODE
3.90
54.49
3.40
1 .603 3.85
14.17
10.8
10.2
10.610.4
10.610.0
10.2
10.4
10.010.4
10.8
10.6
10.010.2
10.610.2
SEC) TAKEN TO
4.00
54.50
3.40
1 .603 3.85
14.17
9.69.2
9.8
9.0
10.2
10,09.8
9.4
9.4
9.8
9.2
10.09.0
9.4
9.6
9.6
TRAVEL
4.
54.
3.
1 . 3.
14.
10.
10.
11 .11 .
10.10.
10.
10.
11.10.
10.
10.
11 .10.
10.
10.
10
47
40
602
84
17
68
02
04
2
8
062
4
06
4
2
4
54
3
1 3
14
1112
11
11
1111
11
11
11
11
11
1112
11
11
11
.20
.49
.40
.603
.85
.17
.0
.0
.6
.2
.4
.2
.8
.4
.8
.6
.0
.2
.0
.2
.6
.2
4
54
3
1 3
14
13
13
1314
14
13
1314
1313
14
13
14
13
1314
.30
.48
.40
.602
.85
.16
.6
.8
.4
.0
.2
.8
.4
.0
.4
.6
.2
.6
.0
.8
.8
.2
xlO 2
xlO~ 3
xlO3 xlO~2
xlO2
THE DISTANCE ON THE
TELEVISION SCREEN
-A31-
TABLE B.10 ELECTROPHORESIS OF lOOppm QUARTZ SUSPENSION AT pH = 3.5
CONDUCTIVITY (X) = 240.0 10~ 4 ohm" 1 nf 1CROSS-SECTIONAL AREA OF THE _ , n -, n ~4 2 ELECTROPHORETIC CELL (A) l.U 1U m
DISTANCE TRAVELLED BY THE PARTICLES -. . ON THE TELEVISION SCREEN (X) ~
CIRCUIT REVERSED
MIGRATION TOWARDS THE
d(m)
V(volt)
I ( amp ) R(ohm)
E(volt
3.70
54.51
3.40
1 .603 3.85
14.17
12 .6
13.4
12.8
13.0
12.8
13.0
13.212.6
13.4
13.6
13.613.0
12.612.8
13.2
12.8
3.80
54.50
3.40
1 .603
3.85
14.17
11.2
11.4
11 .612.2
12.0
11 .6
11 .2
11 .8
11.611.8
12.0
11.4
11.611.2
12.2
11 .4
3.
54.
3.
1 .
3.
14.
10.10.
10.10.
10.
11 .
11 .
10.
11 .10.
10.
11 .10.10.
10.
10.
TIME (SEC) TAKEN
90
52
40
604
85
17
2
04
08
02
6
068
02
4
2
8
4.00
54.47
3.40 1 .602
3.84
14.17
9.89.6
10.2
10.49.6
10.09.4
9.8
10.4
10.09.8
9.4
9.610.2
9.8
9.4
TO TRAVEL
NEGATIVE
4.
54.
3.
1 .
3.
14.
10.10.
10.
11 .
11 .
11.
10.11 .11 .11 .10.11 .11 .11 .10.10.
10
52
40 604
85
17
8
6
82
4
0
8
6
6
0
64
02
68
0 2 m
ELECTRODE
4
54
3
1
3
14
11
11
12
12
1112
1112
12
11
12
12
12
11
12
11
THE DISTANCE
.20
.48
.40
.602
.85
.17
.6
.8
.2
.4
.8
.0
.8
.4
.2
.6
.2
.0
.0
.8
.4
.6
ON
4
54
3
1
3
14
12
13
1213
13
12
12
13
12
1312
13
1212
1312
THE
.30 xlO~2
.50
.40 xlO~3
.603 xlO3
.85 xlO~ 2
.17 xlO 2
.2
.0
.8
.2
.4
.6
.4
.0
.4
.2
.6
.0
.8
.2
.4
.6
TELEVISION SCREEN
-A32-
TABLE B.ll ELECTROPHORESIS OF lOOppm QUARTZ SUSPENSION AT pH = 3.0
CONDUCTIVITY (A)
CROSS-SECTIONAL AREA OF THE ELECTROPHORETIC CELL (A)
DISTANCE TRAVELLED BY THE PARTICLES ON THE TELEVISION SCREEN (X)
= 730.0. 10 4 ohm-4 2 1 .0 10 m
= 14.0 10~2 m
m
MIGRATION TOWARDS THE
d(m)
V(volt)
I (amp)R(ohm)Km)E(volt m- 1 )
3.70
47.41
9.05.27
3.85
12.33
12 .6
13.0
12.8
13.2
12.6
13.4
12.4
13.0
12.8
13.2
13.4
12.4
12.6
12.4
13.012.6
TIME (
3.
47.
9.
5.
3.
12.
11 .
11.
11 .
11.12.
12.
11.
11 .
11.
11.
11 .
12.
11 .
11 .12.
11 .
SEC)
TELEVISION
80
43
027
85
33
6
88
4
02
2
4
04
62
4
2
2
8
3.90
47.42
9.0
5.27
3.85
12.33
11 .0
10.610.811.2
11 .4
10.8
10.410.2
10.411.2
10.610.2
10.8
11 .0
10.6
10.4
TAKEN TO
4.00
47.45
9.0
5.27
3.85
12.33
9.2
9.6
10.010.2
10.09.2
9.8
9.49.0
9.4
9.0
9.6
10.2
9.8
9.4
9.2
TRAVEL
NEGATIVE
4.10
47.409.10
5.27
3.84
12.33
10.6
10.811.2
11 .611.4
10.811.2
11 .0
11.0
11 .610.6
10.811.2
11.4
11 .011.4
ELECTRODE
4.
47.
9.
5.
3.
12.
12.
12.12.
12.
12.
13.12.
12.
12.12.
13.12.
12.
12.
12.
12.
THE DISTANCE
20
44
027
85
33
64
8
02
08
64
2
0
0
06
4
8
ON
4
47
9
5
3
12
13
14
13
13
14
13
13
14
13
13
14
14
13
13
13
13
THE
.30
.42
.0
.27
.85
.33
.8
.2
.2
.4
.0
.6
.4
.2
.6
.2
.0
.2
.8
.4
.6
.8
xlO 2
xlO~ 3xlO3
xlO~2
xlO2
SCREEN
-A33-
TABLE B.I 2 ELECTROPHORESIS OF lOOppm QUARTZ SUSPENSION AT pH = 3.0
CONDUCTIVITY (X)
CROSS-SECTIONAL AREA OF THE ELECTROPHORETIC CELL (A)
DISTANCE TRAVELLED BY THE PARTICLES ON THE TELEVISION SCREEN (X)
CIRCUIT REVERSED
= 730.0 10 4ohm
1 .0 10~4 m2
= 14.0 10~2 m
m" 1
MIGRATION
d(m)V(volt) I ( amp ) R(ohm) Km)E(vglt m- 1 )
3.70
47.43 9.0
5.27 3.85
12.33
13.6
13.8
13.2
13.0
13.4
13.2
14.4
14.2
14.4
13.0
13.613.2
14.814.2
14.8
13.0
TIME (
3
47 9
5 3
12
1212
1312
12
12
12
12
11
1112
12
12
1112
11
SEC
.80
.43
.0
.27
.85
.33
.6
.4
.0
.8
.2
.0
.8
.6
.8
.6
.4
.2
.0
.6
.0
.8
TOWARDS THE
3.90
47.45
9.0
5.27 3.85
12.33
11 .2
10.6
11 .8
11 .0
11.4
10.8
11.6
11 .0
11 .6
11.2
10.8
10.6
11.8
11 .2
11.4
11.4
) TAKEN TO T
THE TELEVISION SCREEN
4.0
47.41 9.0
5.27
3.85
12.33
9.8
10.6
10.8
11.0
9.4
9.29.6
10.49.4
9.6
9.8
10.2
10.4
10.2
9.2
10.0
RAVEL
NEGATIVE ELECTRODE
4.10
47.42
9.0
5.27
3.85
12.33
10.8
11 .0
11 .2
10.8
11 .4
10.611 .8
11.6
11 .8
11.4
11 .6
10.6
11.2
11 .4
11 .0
10.8
4.
47.
9.
5.
3.
12.
11.12.
12.
12.
11.12.
12.
12.
12.
12.
12.
12.
12.12.
11.
12.
20
44
0
27 85
33
8
2
4
08
068
4
02
6
08
8
4
4
47 9
5 3
12
1313
13
13
13
1313
14
14
13
13
13
1314
14
13
.30
.43
.0
.27
.85
.33
.4
.0
.6
.2
.0
.6
.8
.2
.0
.8
.4
.2
.4
.2
.0
.8
xlO 2
xlO~3
xM) 3
xlO~ 2
xM)2
THE DISTANCE ON
-A34-
APPENDIX C
ELECTROPHORESIS OF COLLIERY WASTE-WATER USING HC1
-A35-
TABLE C.I ELECTROPHORESIS OF COLLIERY WASTE-WATER AT pH = 8.6
CONDUCTIVITY (X) = 1.36 ID" 1 ohm" 1 m" 1CROSS-SECTIONAL AREA OF THE -, _ , n~4 2 ELECTROPHORETIC CELL (A) m
DISTANCE TRAVELLED BY THE _ ? PARTICLES ON THE TELEVISION = 28.0 10 m SCREEN (X)
MIGRATION TOWARDS THE
d(m)
V(volt)
I ( amp )
R(ohm)
Km)
E(volt m-1)
3.70
18.462.93
6.30
8.568
2.15
18.2
18.819.2
18.6
20.420.6
19.8
18.0
18.018.8
19.419.8
20.2
18.0
18.619.8
18.4
18.8
3
182
68
2
1516
1616
1616
16
16
1715
16
16
17
17
15
15
15
16
TIME TAKEN
TELEVISION
.75
.47
.93
.30
.573
.15
.4
.2
.6
.0
.8
.8
.2
.8
.2
.6
.4
.6
.0
.6
.8
.6
.8
.6
3.
18.2.
6.8.
2.
14.14.
15.14.
14.14.
14.14.
15.14.
14.
14.
14.14.
14.
15.
15.15.
80
47
93
30
573
15
82
06
04
2
6
08
06
84
82
0
0
TO TRAVEL THE
SCREEN ( SEC) .
3
18
2
68
2
1313
13
14
1313
1313
1313
1414
13
13
13
13
13
13
POSITIVE
.85
.51
.94
.30
.562
.16
.6
.2
.8
.0
.4
.8
.2
.2
.6
.4
.2
.0
.4
.8
.6
.0
.6
.4
318
2
68
2
14
13
1414
1413
14
13
1414
1313
13
14
1414
1314
ELECTRODE
.90
.51
.94
.30
.562
.16
.2
.8
.0
.6
.0
.6
.2
.8
.2
.6
.6
.6
.8
.0
.4
.8
.8
.2
3182
68
2
1615
16
15
1616
1616
16
15
1616
1615
1515
16
16
.95 xlO 2
.49
.93 xlO~ 3
.30 xlO3
.582 xlO~2
.15 xlO2
.8
.6
.2
.8
.2
.4
.0
.2
.2
.8
.4
.0
.0
.6
.8
.8
.2
.4
DISTANCE ON THE
-A36-
TABLE C.2 ELECTROPHORESIS OF COLLIERY WASTE-WATER AT pH = 8.6
CONDUCTIVITY (X)
CROSS-SECTIONAL AREA OF THE ELECTROPHORETIC CELL (A)
DISTANCE TRAVELLED BY THE PARTICLES ON THE TELEVISION SCREEN (X)
MIGRATION TOWARDS THE
d(m)V(volt)
I ( amp )R(ohm)Km)E(volt m-1)
4.05
18.57
2.95
6.29
8.56
2.169
19.6
20.2
20.0
18.8
18.0
18.6
19.6
19.2
18.8
20.0
19.8
18.6
19.8
20.0
18.4
18.2
18.6
18.2
4.10
18.58
2.95
6.29
8.57
2.169
17.2
17.0
16.6
16.0
16.8
16.2
17.0
16.4
16.8
17.2
16.6
16.2
17.0
17.2
16.0
16.8
16.4
16.6
4.15
18.56
2.95
6.29
8.56
2 .167
15.8
15.2
15.0
14.8
15.0
14.4
14.0
14.2
14.8
14.6
14.0
14.8
14.6
14.2
13.4
14.6
14.2
13.8
= 1 .36 10 ohm m
= 1 .0 10~4 m2
= 28.0 10~2 m
NEGATIVE ELECTRODE
4.20
18.55
2.94
6.31
8.58
2 .162
13.8
13.4
14.0
13.8
13.2
13.6
14.0
13.0
13.6
12.8
13.4
14.2
13.2
13.8
13.4
14.0
14.2
13.2
TIME (SEC) TAKEN TO TRAVEL THE
THE TELEVISION SCREEN
4.25
18.57
2.95
6.29
8.56
2.169
14.6
14.8
14.8
15.2
15.4
14.6
14.4
15.0
15.4
15.4
14.8
14.6
15.4
15.8
15.2
16.0
16.0
15.6
DISTANCE
4.30
18.59
2.95
6.30
8.57
2.169
16.8
16.4
17.2
17.0
16.4
17.6
17.2
16.8
17.0
17.6
17.8
17.4
18.0
18.2
17.4
17.6
18.2
18.0
ON
xlO 2
xlO~ 3
xlO 3
xlO~ 2
xlO2
-1
-A37-
TABLE C.3 ELECTROPHORESIS OF COLLIERY WASTE-WATER AT pH = 8.6
CONDUCTIVITY (X)
CROSS-SECTIONAL AREA OF THE ELECTROPHORETIC CELL (A)
DISTANCE TRAVELLED BY THE PARTICLES ON THE TELEVISION SCREEN (X)
CIRCUIT REVERSED
= 1 .36 10 ohm m
= 1 .0 10~4 m2
= 28.0 10~ 2 m
MIGRATION TOWARDS THE POSITIVE ELECTRODE
d(m)V(volt) I ( amp ) R(ohm) Km)E(volt
3.7018.55 2.94 6.31 8.58
2.16
19.218.618.819.018.218.617.819.218.018.017.818.418.418.217.617.818.618.8
TIME (
3.7518.55 2.94 6.31 8.58
2.16
15.815.616.416.015.816.216.015.616.416.816.815.615.816.616.016.616.816.2
3.8018.56 2.94 6.31 8.58
2 .16
14.213.814.614.014.413.815.215.014.814.215.014.613.815.215.014.414.614.0
3.8518.58 2.94 6.31 8.57
2.17
12.812.413.413.612.612.212.813.013.013.412.812.613.012.413.612.812.412.2
SEC) TAKEN TO TRAVEL THE
THE TELEVISION SCREEN
3.9018.54 2.94 6.31 8.58
2.16
13.014.213.812.813.413.012.814.014.614.413.813.414.014.212.813.213.613.4
DISTANCE
3.95 xlO 218.51 2.94 xlO~ 3 6.30 xlO 3 8.56 xlO~ 2
2.16 xlO2
15.615.216.016.215.816.416.015.615.415.015.616.216.615.816.415.416.016.2
ON
-A38-
TABLE C.4 ELECTROPHORESIS OF COLLIERY WASTE-WATER AT pH = 8.6
CONDUCTIVITY (X)CROSS-SECTIONAL AREA OF THE ELECTROPHORETIC CELL (A)DISTANCE TRAVELLED BY THE PARTICLES ON THE TELEVISION SCREEN (X)
CIRCUIT REVERSED
= 1 .36 10 ohm ± m-4 9
= 1 .0 10 m
= 28.0 10~ 2 m
MIGRATION TOWARDS THE NEGATIVE ELECTRODE
d(m)V(volt) I ( amp ) R(ohm) Km)E(volt
nT 1 )
4.0518.56 2.95
6.30 8.56
2.17
21 .021.221.2
20.819.8
20.621 .021 .020.620.820.420.421 .220.621.020.819.820.4
TIME (
4.1018.50 2.94
6.30 8.56
2 .16
15.2
15.615.0
14.614.8
15.415.616.214.6
16.015.2
16.414.8
15.415.8
15.0
15.616.2
4.1518.53
2 .94 6.30 8.56
2 .16
14.815.214.815.014.614.614.814.214.014.414.214.613.814.013.613.813.414.2
4.2018.54 2.94 6.30 8.56
2.16
13.213.013.212.813.013.412.612.213.012.812.412.213.213.212.812.212.812.6
SEC) TAKEN TO TRAVEL THETHE TELEVISION SCREEN.
4.2518.52
2 .94 6.30 8.56
2.16
13.613.613.213.414.014.213.814.414.614.014.413.213.814.013.414.614.214.6
DISTANCE
4.3018.51 2.94 6.30 8.56
2.16
15.215.615.416.616.216.015.416.615.815.816.416.215.416.016.015.615.816.4
ON
xlO 2
xlO~ 3 xlO 3 xlO~ 2
xlO2
-A39-
TABLE C.5 ELECTROPHORESIS OF COLLIERY WASTE-WATER AT pH = 7.8
CONDUCTIVITY (X)
CROSS-SECTIONAL AREA OF THE ELECTROPHORETIC CELL (A)
DISTANCE TRAVELLED BY THE PARTICLES ON THE TELEVISION SCREEN (X)
= 1 .38 10 l ohm l m1-4 2
= 1 .0 10 m
= 28.0 10~ 2 m
MIGRATION TOWARDS THE POSITIVE ELECTRODE
d(m)V(volt) I ( amp ) R(ohm) Km)E(volt M' 1 )
3.7018.20 2.93 6.21 8.57
2.12
17.617.417.818.017.618.017.217.619.817.217.018.217.217.817.417.6
TIME (
3.7518.23 2.94 6.20 8.56
2.13
17.016.816.816.016.415.815.615.815.415.215.815.216.015.415.615.4
3.8018.21 2.94 6.20 8.55
2.13
14.014.213.814.214.814.414.214.614.814.814.614.214.614.414.013.8
3.8518.23 2.94 6.20 8.56
2.13
13.013.412.813.013.613.212.612.813.213.412.613.213.612.813.413.0
SEC) TAKEN TO TRAVEL THE
THE TELEVISION SCREEN
3.9018.23 2.94 6.20 8.56
2.13
13.613.813.414.013.413.613.213.814.214.013.413.813.214.214.013.6
DISTANCE
3.9518.24 2.94 6.20 8.56
2.13
14.815.014.615.415.415.014.815.214.614.815.214.615.215.414.614.8
ON
xlO 2
xlO" 3 xlO 3 xlO~ 2
xlO 2
-A40-
TABLE C.6 ELECTROPHORESIS OF COLLIERY WASTE-WATER AT pH = 7.8
CONDUCTIVITY (X)
CROSS-SECTIONAL AREA OF THE ELECTROPHORETIC CELL
DISTANCE TRAVELLED BY THE PARTICLES ON THE TELEVISION SCREEN
= 1 .38 10 ohm -1- m-4 2
= 1 .0 10 m
= 28.0 10~2 m
MIGRATION TOWARDS THE NEGATIVE ELECTRODE
d(m)V(volt) I ( amp ) R(ohm) Km)E(volt
4.05
18.22
2.94
6.19
8.55
2.13
19.4
20.2
19.6
19.2
19.8
19.4
19.0
20.2
19.6
19.0
19.8
19.8
19.2
20.0
20.0
19.8
TIME (
4.10
18.25
2.94
6.21
8.57
2.13
16.4
16.6
17.2
16.8
15.8
16.2
16.8
16.4
16.2
16.0
15.8
16.4
16.6
16.8
15.8
15.8
4.15
18.24
2.94
6.20
8.56
2.13
15.2
15.6
15.0
15.8
14.8
15.0
15.4
15.8
14.6
14.8
15.2
14.8
15.6
15.4
15.0
14.6
4.20
18.25
2.94
6.21
8.57
2.13
14.8
13.8
14.2
14.4
14.0
13.8
13.4
14.0
13.2
13.6
14.4
14.0
13.6
13.2
14.2
13.4
SEC) TAKEN TO TRAVEL THE
THE TELEVISION SCREEN
4.25
18.21
2.94
6.20
8.55
2.13
14.8
15.2
15.6
16.2
16.015.4
15.0
14.8
16.4
16.0
15.6
15.4
15.8
16.2
15.6
15.8
DISTANCE
4.30 xlO 2
18.23
2.94 xlO~ 3
6.20 xlO 3
8.56 xlO~2
2.13 xlO2
16.8
17.4
17.0
16.6
17.2
16.8
16.6
17.0
17.4
16.6
16.8
17.2
16.8
17.0
17.4
17.2
ON
-A41-
TABLE C.7 ELECTROPHORESIS OF COLLIERY WASTE-WATER AT pH = 7.8
CONDUCTIVITY (X) =1.38 lO" 1 ohm" 1 m" 1CROSS-SECTIONAL AREA OF THE _ n n~4 2 ELECTROPHORETIC CELL (A) ~ m
DISTANCE TRAVELLED BY THE _ ? PARTICLES ON THE TELEVISION = 28.0 10 m SCREEN (X)
CIRCUIT REVERSED
MIGRATION TOWARDS THE
d(m)V(volt)I ( amp )R(ohm)Km)E(volt
3.7018.432.976.218.56
2.15
16.816.417.016.816.217.016.816.616.216.016.416.216.616.016.816.6
TIME (ON THE
3.7518.472.986.208.55
2.16
15.415.215.816.216.015.615.215.615.815.015.615.815.216.015.415.6
SEC) TAKEN
3.8018.442.976.218.57
2.15
14.214.013.613.814.213.614.213.813.413.813.613.414.013.813.413.6
BY THE
POSITIVE ELECTRODE
3.8518.452.976.218.57
2 .15
12.812.413.013.212.612.412.612.813.212.412.812.212.812.012.612.0
3.9018.462.976.228.58
2.15
14.213.813.614.014.613.814.815.215.014.613.814.414.813.614.414.2
3.95 xlO 218.472.97 xlO" 36.22 xlO 38.58 xlO~ 2
21.5 xlO2
15.015.816.216.015.815.615.416.015.416.215.2
15.815.015.215.815.4
PARTICLES TO TRAVEL
TELEVISION SCREEN
-A42-
TABLE C.8 ELECTROPHORESIS OF COLLIERY WASTE-WATER AT pH = 7.8
CONDUCTIVITY (X)CROSS-SECTIONAL AREA OF THE ELECTROPHORETIC CELL (A)DISTANCE TRAVELLED BY THE PARTICLES ON THE TELEVISION SCREEN (X)
CIRCUIT REVERSED
MIGRATION TOWARDS THE
d(m)V(volt) I ( amp ) R(ohm) Km)E(volt
4.0518.45 2.97
6.21 8.57
2.15
20.219.819.219.419.819.420.020.019.619.419.819.219.619.619.019.2
TIME (
ON THE
4.10
18.48 2.98 6.20 8.56
2.16
14.814.815.415.614.615.014.414.215.014.214.614.2
14.814.614.414.6
SEC) TAKEN
4.1518.49 2.98 6.21 8.56
2 .16
13.212.812.413.012.212.812.613.212.413.212.812.412.812.612.212.4
BY THE
= 1 .38 10 ohm m
=1.0 10~4 m2
= 28.0 10~ 2 m
NEGATIVE ELECTRODE
4.2018.51 2.99 6.19 8.54
2.17
12.211 .611 .612.012.211 .812.211 .611.411 .811.212.012.011 .611.211.4
4.2518.47 2.98 6.20 8.55
2.16
14.614.014.414.415.015.214.814.614.214.814.414.214.214.014.614.0
4.3018.50 2.98 6.21 8.57
2.16
16.215.816.215.616.015.415.815.615.415.816.216.015.415.615.415.8
xlO 2
xlO~ 3 xlO 3 xlO~ 2
xlO2
PARTICLES TO TRAVEL
TELEVISION SCREEN
-A43-
TABLE C.9 ELECTROPHORESIS OF COLLIERY WASTE-WATER AT pH = 7.0
CONDUCTIVITY (X) = 1.44 10 ohm mCROSS-SECTIONAL AREA OF THE _ n ~4 2 ELECTROPHORETIC CELL (A) ~ m
DISTANCE TRAVELLED BY THE PARTICLES,, R _ -, _-2 ON THE TELEVISION SCREEN ( X) m
MIGRATION TOWARDS THE
d(m)V(volt) I ( amp ) R(ohm) Km)E(volt m" 1 )
3.7017.85 3.00 5.93 8.57
2.08
15.615.416.216.015.415.816.816.216.216.415.616.416.816.016.615.8
TIME (
ON THE
3.7517.89 3.01 5.95 8.56
2.09
15.615.815.014.614.815.214.815.614.614.814.214.815.014.415.215.0
SEC) TAKEN
3.8017.87 3.0 5.94 8.55
2.09
13.613.412 .812 .813.213.412.612.613.413.012.412.812.413.613.213.4
POSITIVE ELECTRODE
3.8517.90 3.01 5.95 8.56
2.09
12.212.412.012.412.811 .811.611 .811 .812.212.812.611.612.412.811 .4
TO TRAVEL THE
3.9017.87 3.01 5.94 8.55
2.09
12.813.212.813.412.613.612.813.413.213.413.213.012.813.412.612.4
DISTANCE
3.95 xlO 217.88 3.01 xlO~ 3 5.94 xlO3 8.55 xlO~ 2
2.09 xlO 2
14.615.815.014.413.814.215.415.814.814.214.615.414.614.614.214.6
TELEVISION SCREEN
-A44-
TABLE C.10 ELECTROPHORESIS OF COLLIERY WASTE-WATER AT pH = 7.0
CONDUCTIVITY (A) CROSS-SECTIONAL AREA OF THE
ELECTROPHORETIC CELL (A)
DISTANCE TRAVELLED BY THE
PARTICLES ON THE TELEVISION
SCREEN (X)
= 1 .44 10 ohm
-4 7 = 1.0 10 m
= 28.0 10~ 2 m
MIGRATION TOWARDS THE NEGATIVE ELECTRODE
d(m)V(volt) I (amp) R(ohm) Km)E(volt m-1)
4.0517.90
3.01 5.95 8.56
2.09
18.218.617.817.418.018.818.218.218.818.417.618.618.018.417.818.0
TIME (
4.1017.93 3.02 5.94 8.55
2.10
16.616.215.616.815.216.015.815.615.415.615.215.015.415.815.015.2
4.1517.94 3.02 5.94 8.55
2 .10
14.213.613.214.013.814.213.413.813.613.413.014.213.813.413.213.6
4.2017.92 3.01 5.95 8.57
2.09
13.613.213.013.813.213.613.413.814.214.013.213.613.814.013.413.6
SEC) TAKEN TO TRAVEL THE
THE TELEVISION SCREEN
4.2517.91 3.01 5.95 8.57
2.09
15.015.415.216.416.016.215.415.816.415.815.215.615.615.416.215.8
DISTANCE
4.3017.93 3.02 5.94 8.55
2.10
16.616.216.016.416.817.016.216.816.416.816.016.217.016.816.416.2
ON
1(T 2
icT 310 3 ID'2
10 2
-A45-
TABLE C.ll ELECTRO PHORESIS OF COLLIERY WASTE -WATER AT pH = 7.0
CONDUCTIVITY (X)CROSS-SECTIONAL AREA OF THE ELECTRO PHORETIC CELL (A)DISTANCE TRAVELLED BY THE PARTICLES ON THE TELEVISION SCREEN (X)
CIRCUIT REVERSED
= 1 .44 10 ohm "- m
=1.0 10~4 m2
= 28.0 10~ 2 m
MIGRATION TOWARDS THE POSITIVE ELECTRODE
d(m)V(volt) I ( amp ) R ( ohm ) Km)E(vplt m'1 )
3.7018.15
3.05 5.95 8.57
2.12
15.415.0
15.615.2
16.216.0
15.615.4
15.215.815.815.015.215.615.416.0
TIME (
3.7518.19 3.06 5.94 8.56
2.13
14.614.814.214.614.415.015.415.014.814.014.614.414.215.014.814.6
SEC ) TAKEN
3.8018.17 3.06 5.94 8.56
2.12
13.212.813.212.612.413.013.412.812.812.413.013.012.613.212.412.6
3.8518.20 3.06 5.95 8.56
2.13
12.211.811 .412.011 .811 .612.212.012.611.411 .812.212.012.211.811.6
TO TRAVEL THE
3.9018.12 3.04 5.96 8.58
2.11
13.814.213.614.414.613.814.014.413.413.814.414.813.614.614.214.0
DISTANCE
3.9518.17 3.06 5.94 8.56
2.13
14.814.615.215.015.615.816.014.815.415.615.215.814.815.015.415.4
ON
xlO 2
xlO~ 3 xlO 3 xlO~ 2
xlO 2
THE TELEVISION SCREEN
-A46-
TABLE C.12 ELECTROPHORESIS OF COLLIERY WASTE-WATER AT Ph = 7.0
CONDUCTIVITY (\)
CROSS-SECTIONAL AREA OF THE ELECTROPHORETIC CELL (A)
DISTANCE TRAVELLED BY THE PARTICLES ON THE TELEVISION SCREEN (X)
CIRCUIT REVERSED
= 1.44 10 A ohin m
-4 2 = 1.0 10 m
= 28.0 10~ 2 m
MIGRATION TOWARDS THE NEGATIVE ELECTRODE
d(m)V(volt)I ( amp )R(ohm)Km)E(volt m' 1 )
4.05
18.143.055.95
8.56
2.12
18.017.617.417.818.2
18.017.617.2
18.217.817.217.6
17.4
17.417.8
17.6
TIME (
4.10
18.183.065.94
8.56
2 .13
13.813.614.014.2
13.613.4
13.813.2
13.613.2
13.414.013.8
14.2
13.4
13.6
SEC) TAKEN
4.15
18.153.055.95
8.57
2.12
11 .611 .812.2
12.212 .0
11 .811 .411.612.0
11 .411 .612.0
11 .812.2
11.4
11 .8
4.20
18.173.065.94
8.56
2.13
12.011.2
11 .4
11 .011 .611 .811.811.411 .411 .611 .211.2
11 .012.011.611.8
TO TRAVEL THE
4.2518.143.055.958.56
2.12
14.214.014.213.813.614.413.814.014.214.614.213.813.814.014.213.6
DISTANCE
4.30 xlO 218.203.06 xlO~ 3
5.95 xlO 38.56 xlO~ 2
2.13 xlO 2
14.614.814.4
15.014.814.615.2
15.415.015.414.815.214.6
15.014.815.2
ON
THE TELEVISION SCREEN
-A47-
TABLE C.I 3 ELECTROPHORESIS OF COLLIERY WASTE -WATER AT pH = 6.0
CONDUCTIVITY (X)
CROSS -SECTIONAL AREA OF THE ELECTROPHORETIC CELL (A)DISTANCE TRAVELLED BY THE PARTICLES ON THE TELEVISION SCREEN (X)
= 1 .58 10 x ohm ± m
=1.0 10~ 4 m2
= 28.0 10~ 2 m
MIGRATION TOWARDS THE POSITIVE ELECTRODE
d(m)V(volt) I ( amp ) R ( ohm ) Km)E(volt m-1)
3.7015.18 2.80 5.42 8.57
1.77
18.819.018.417.617.817.418.017.618.418.817.617.217.817.617.418.0
TIME (
3.7516.24 3.0 5.41 8.55
1.90
16.216.616.416.416.015.615.816.015.415.816.215.615.616.016.216.0
3.8016.31 3.01 5.42 8.56
1 .91
14.214.414.014.613.813.414.014.213.613.813.814.214.613.614.413.8
3.8516.29 3.01 5.41 8.55
1 .91
12.612.412.012.612. 812.412.212.612.212.012.612.412.812.012.412.2
SEC) TAKEN TO TRAVEL THE
THE TELEVISION SCREEN
3.9016.25 3.0 5.42 8.56
1 .90
13.414.614.815.213.815.014.613.013.613.214.814.815.015.213.413.2
DISTANCE
3.95 xlO 216.28 3.01 xlO~ 3 5.41 xlO 3 8.55 xlO~ 2
1.91 xlO 2
16.215.415.615.616.015.816.215.414.816.015.415.815.415.216.215.2
ON
-A48-
TABLE C.14 ELECTROPHORESIS OF COLLIERY WASTE -WATER AT pH = 6.0
CONDUCTIVITY (A)
CROSS-SECTIONAL AREA OF THE ELECTROPHORETIC CELL (A)
DISTANCE TRAVELLED BY THE PARTICLES ON THE TELEVISION SCREEN (X)
= 1 .58 10 ohm m
=1.0 10~ 4 m2
= 28.0 10~ 2 m
MIGRATION TOWARDS THE NEGATIVE ELECTRODE
d(m)V(volt)I ( amp )R(ohm)Km)E(volt m-1)
4.0517.23
3.185.428.56
2.01
17.818.418.217.818.618.217.617.417.618.217.418.617.618.417.818.4
TIME (
4.1017.283.195.428.56
2.01
16.416.015.816.416.416.215.615.816.016.215.616.016.216.416.616.8
SEC ) TAKEN
4.15
16.853.115.428.56
1 .97
13.614.014.213.613.814.213.613.613.813.414.214.014.214.413.613.8
4.2016.91
3.125.428.56
1 .97
13.213.613.012.813.413.612.812.613.413.012 .612.412.813.013.412.4
TO TRAVEL THE
4.2516.943.135.418.55
1.98
16.016.416.015.816.617.217.016.817.016.616.416.816.616.016.816.0
DISTANCE
4.30 xlO 217.263.18 xlO~ 35.43 xlO 38.58 xlO~ 2
2.01 xlO 2
17.216.616.816.616.416.016.816.216.417.017.416.616.216.016.016.8
ON
THE TELEVISION SCREEN
-A49-
TABLE C.I5 ELECTROPHORESIS OF COLLIERY WASTE-WATER AT pH = 6.0
CONDUCTIVITY
CROSS-SECTIONAL AREA OF THE ELECTROPHORETIC CELL (A)
DISTANCE TRAVELLED BY THE PARTICLES ON THE TELEVISION SCREEN (X)
CIRCUIT REVERSED
= 1.58 10 ohm
=1.0 10~ 4 m2
= 28.0 10~ 2 m
m
MIGRATION TOWARDS THE POSITIVE ELECTRODE
d(m)V(volt) I ( amp ) R(ohm) Km)E(volt m-1)
3.7016.94 3.13 5.41 8.55
1 .98
16.216.016.015.615.415.815.616.215.815.816.216.015.415.615.815.6
TIME (
3.7516.97 3.13 5.42 8.57
1.98
15.415.015.214.814.615.014.214.414.615.414.814.215.214.414.614.2
3.8017.06 3.15 5.42 8.56
1.99
12.612.813.213.012 .012.412 .813.213.012.613.212 .612.413.012.412 .6
3.8517.09 3.15 5.43 8.57
1.99
11.611 .812.212.011 .611.812.011 .412.011.411.812.211.611.611.811.6
SEC) TAKEN TO TRAVEL THE
THE TELEVISION SCREEN
3.9017.08
3^15 5.42 8.57
1.99
14.614.014.413.813.614.213.814.613.413.614.013.013.614.414.213.4
DISTANCE
3.95 xlO 217.12 3.16 xlO" 3 5.42 xlO 3 8.56 xlO~ 2
2.0 xlO2
15.215.615.416.215.815.616.015.815.415.216.216.015.615.415.215.8
ON
-A50-
TABLE C.16 ELECTROPHORESIS OF COLLIERY WASTE-WATER AT pH = 6.0
CONDUCTIVITY (X)
CROSS-SECTIONAL AREA OF THE ELECTROPHORETIC CELL (A)
DISTANCE TRAVELLED BY THE PARTICLES ON THE TELEVISION SCREEN (X)
CIRCUIT REVERSED
MIGRATION TOWARDS
d(m)V(volt)I ( amp )R(ohm)Km)E(volt m-1)
4.0517.043.145.438.57
1.99
17.417.618.218.017.617.817.218.018.217.217.417.818.017.618.217.8
TIME (
4.1016.983.135.428.57
1 .98
14.615.415.014.415.214.815.014.214.014.615.214.414.214.614.814.4
4.1516.953.125.438.58
1,97
13.213.012.612.412.813.012 .612 .813.012 .412.812 .613.213.412.812.4
= 1 .58 10 ohm m
= 1 .0 10~4 m2
= 28.0 10~ 2 m
THE NEGATIVE ELECTRODE
4.2016.973.135.428.57
1,98
11 .612.412.611 .811.612.012.211.411.011.811.211.211.412.212.011 .6
SEC) TAKEN TO TRAVEL THE
THE TELEVISION SCREEN
4.2516.93
31 .25.438.57
1,97
13.814.413.614.614.013.813.414.014.413.814.214.413.414.614.213.6
DISTANCE
4.3016.983.135.428.57
1,98
15.214.614.815.014.614.215.415.214.414.815.015.415.015.214.414.2
ON
xlO 2
xlO~ 3xlO 3xlO~ 2
xlO 2
-A51-
TABLE C.17 ELECTROPHORESIS OF COLLIERY WASTE-WATER AT pH = 5.2
CONDUCTIVITY (X) =1.61 ID" 1 ohm" 1 m" 1
CROSS-SECTIONAL AREA OF THE _ -4 2 ELECTROPHORETIC CELL (A) - l.U 1U m
DISTANCE TRAVELLED BY THEPARTICLES ON THE TELEVISION =28.0 10 mSCREEN (X)
MIGRATION TOWARDS THE POSITIVE ELECTRODE
d(ra)
V(volt) I ( amp ) R(ohm) Km)E(volt m-1)
3.70
16.89
3.18
5.31
8.55
1 .98
15.6
15.4
16.2
16.0
15.6
15.8
16.4
16.0
15.8
15.0
15.0
15.4
15.2
15.4
15.6
15.2
TIME (
3.75
16.94
3.19
5.31
8.55
1.98
14.8
14.4
15.0
15.2
14.8
14.6
14.0
14.4
14.2
14.6
14.8
14.4
15.0
14.0
15.2
14.2
3.80
16.98
3.20
5.31
8. .54
1 .99
13.4
13.2
13.6
13.0
14.2
13.0
14.2
13.6
14.0
13.2
13.8
12.8
13.4
12.8
13.2
13.0
3.85
17.05
3.21
5.31
8.55
1.99
12.2
12.0
11 .6
11 .8
12.4
11.4
11.8
12.0
11 .6
11 .4
12.0
12.0
11 .8
11 .4
11.6
11 .8
SEC) TAKEN TO TRAVEL THE
THE TELEVISION SCREEN
3.90
17.06
3.21
5.31
8.55
1.99
14.0
13.6
13.8
13.0
13.4
13.4
14.0
13.2
13.4
13.0
13.2
13.2
14.0
13.8
13.8
13.6
DISTANCE
3.95
17.08
3.21
5.32
8.57
1.99
14.6
14.8
15.2
14.4
14.8
14.8
15.0 .
14.4
14.8
14.4
14.2
14.0
14.6
14.2
14.6
14.0
ON
_
xlO 2
xlO~ 3
xlO3
xlO~2
xlO2
-A 52-
TABLE C.I 8 ELECTROPHORESIS OF COLLIERY WASTE -WATER AT pH = 5.2
CONDUCTIVITY (X)CROSS-SECTIONAL AREA OF THE ELECTRO PHORETIC CELL (A)
DISTANCE TRAVELLED BY THE PARTICLES ON THE TELEVISION SCREEN (X)
= 1 .61 10 ohm m'-4 7
= 1.0 10 m
= 28.0 10~ 2 m
MIGRATION TOWARDS THE NEGATIVE ELECTRODE
d(m)V(volt) I ( amp ) R(ohm) Km)E(volt m-1)
4.0516.97 3.19 5.32 8.56
1 .98
17.216.417.017.216.816.016.216.016.415.815.817.016 .616.816.416.2
TIME (
4.1017.02 3.20 5.32 8.56
1 .99
15.615.816.216.015.416.215.616.015.415.215.815.015.015.615.2
15.6
4.1517.05
3.21 5.31 8.55
1 .99
13.813.413.413.614.013.013.613.214.2
14.013.213.814.213.214.013.4
4.2017.08 3.21 5.32 8.57
1 .99
13.212.612.813.013.412.212.012.213.012.012.813.212.412.612.212.4
SEC) TAKEN TO TRAVEL THE
THE TELEVISION SCREEN
4.2517.07
3.21 5.32 8.56
1 .99
16.215.815.216.015.816.215.415.615.2
15.615.215.615.415.815.216.0
DISTANCE
4.30 xlO 217.15 3.23 xlO~ 3 5.31 xlO 3 8.55 xlO~ 2
2.01 xlO2
16.417.016.616.816.216.016.816.015.816.215.816.016.416.216.616.4
ON
1
-A53-
TABLE C.I9 ELECTROPHORESIS OF COLLIERY WASTE-WATER .AT pH = 5.2
CONDUCTIVITY (X)CROSS- SECTIONAL AREA OF THE ELECTROPHORETIC CELL (A)DISTANCE TRAVELLED BY THE PARTICLES ON THE TELEVISION SCREEN (X)
CIRCUIT REVERSED
= 1 .61 10 ohm L IT-4 2 = 1 .0 10 m
= 28.0 10~ 2 m
MIGRATION TOWARDS THE POSITIVE ELECTRODE
d(m)V(volt)I ( amp )R(ohm)l(m)E(volt m-1)
3.7017.09
3.215.328.57
1 .99
15.615.415.014.814.615.215.615.014.: 615.214.815.614.815.214.615.2
TIME (
3.7517.123.225.328.56
2.0
14.814.214.014.414.614.214.015.014.413.813.814.214.014.614.813.8
3.8017.113.225.318.56
2.0
12.212.012.212.411 .811 .812.412.812.612.212.812.012.012.412.612.2
3.8517.153.235.318.55
2 .01
11 .812.212.011 .612.012.411 .811.611 .411 .611 .212.011 .811 .212.411.4
SEC) TAKEN TO TRAVEL THETHE TELEVISION SCREEN
3.9016.863.175.328.56
1 .97
13.814.214.213.614.014.413.413.813.613.413.613.214.214.013.813.2
DISTANCE
3.95 10 216.953.19 10~ 35.31 10 38.55 10~ 2
1.98 102
15.214.814.615.215.015.415.615.214.815.015.615.415.215.014.614.8
ON
-A54-
TABLE C.20 ELECTROPHORESIS OF COLLIERY WASTE-WATER AT pH = 5.2
CONDUCTIVITY (X)
CROSS-SECTIONAL AREA OF THE ELECTROPHORETIC CELL (A)
DISTANCE TRAVELLED BY THE PARTICLES ON THE TELEVISION SCREEN (X)
CIRCUIT REVERSED
= 1 .61 10 ohm ± m-4 2 = 1.0 10 m
= 28.0 10~ 2 m
MIGRATION TOWARDS THE NEGATIVE ELECTRODE
d(m)V(volt) I ( amp ) R(ohm) Km)E(volt m-1)
4.0516.93 3.18 5.32 8.57
1 .98
17.217.817.217.617.018.018.217.417.617.418.017.817.618.217.217.8
TIME (
4.1016.96 3.19 5.32 8.56
1 .98
15.614.814.413.615.214.215.414.814.614.213.813.614.815.015.615.0
SEC ) TO
4.1516.88 3.17 5.32 8.57
1 .97
13.813.414.012.212.813.212.612.012.812.012.212.612.413.213.412.4
TRAVEL THE
4.2016.91
3.18 5.32 8.56
1.98
12.411.811 .812.011 .612.012.211 .411 .211 .611.812.211.211 .011 .011.2
4.2516.92
3.18 5.32 8.57
1.98
13.412.813.014.214.013.813.613.213.813.213.413.613.013.413.613.8
4.3016.94 3.19 5.31 8.55
1 .98
14.214.615.215.014.815.014.414.214.214.814.814.414.614.614.815.0
xlO 2
xlO~ 3 xlO 3 xlO~ 2
xlO2
DISTANCE ON THE
TELEVISION SCREEN
-A55-
TABLE C.21 ELECTROPHORESIS OF COLLIERY WASTE-WATER AT pH = 4.9
CONDUCTIVITY (X) = 1.61 10 ohm mCROSS-SECTIONAL AREA OF THE , _ - -4 2 ELECTROPHORETIC CELL (A) - i.U 1U m
DISTANCE TRAVELLED BY THE ~ PARTICLES ON THE TELEVEISION = 28.0 10 m SCREEN (X)
MIGRATION TOWARDS THE NEGATIVE ELECTRODE
d(m)V(volt) I ( amp ) R { ohm ) Km)E(volt m" 1
3.7017.06
3.22 5.30 8.53
2.0
15.215.615^414.814.615.015.614.815.015.414.815.615.215.014.615.2
TIME
3.7517.10 3.23 5.30 8.52
2.01
14.613.814.014.014.214.413.613.814.213.614.614.413.614.013.813.4
(SEC) TAKEN
3.8017.08 3.22 5.30 8.54
2.0
13.013.413.213.012.612.813.413.012.612.813.213.412.813.212.613.0
3.85
17.11 3.23 5.30 8.53
2.01
12.412.012.411 .811.211 .611 .812.211 .211 .611 .412.212.011 .612.411 .8
TO TRAVEL THE
3.9017.10 3.23 5.30 8.52
2.01
13.813.213.413.013.213.814.014.213.413.613.213.813.013.013.214.0
DISTANCE
3.9517.15 3.24 5.30 8.52
2.01
14.214.615.014.815.214.214.414.814.615.214.814.414.614.215.014.0
ON
ID' 2
xlO~ 3 xlO 3 xlO~ 2
xlO2
THE THE TELEVISION SCREEN
-A56-
TABLE C.22 ELECTROPHORESIS OF COLLIERY WASTE-WATER AT pH = 4.9
CONDUCTIVITY (X) = 1.61 10 ohm mCROSS-SECTIONAL AREA OF _ -4 2 THE ELECTROPHORETIC CELL (A) ~ mDISTANCE TRAVELLED BY THE ? PARTICLES ON THE TELEVISION = 28.0 10 m SCREEN (X)
MIGRATION TOWARDS THE POSITIVE ELECTRODE
d(m)V(volt) I ( amp ) R(ohm) Km)E(volt
4.0517.07 3.22 5.30 8.54
2.0
15.415.015.215.816.216.015.615.415.015.816.215.416.015.015.215.2
TIME (
4.1017.13 3.23 5.30 8.54
2 .01
14.414.815.014.614.414.014.214.814.414.214.614.814.014.814.015.0
4.1517.05
3.22 5.30 8.53
2.0
13.614.013.813.413.214.013.613.213.813.213.613^813.413.414.013.6
4.2017.11 3.23 5.30 8.53
2.01
13.012.812.613.212.212.212.612.412.812.012.012.212.412.812.012.6
SEC) TAKEN TO TRAVEL THETHE TELEVISION SCREEN
4.2517.13 3.23 5.30 8.54
2.01
15.015.415.616.015.415.815.015.216.015.615.615.815.215.815.615.0
DISTANCE
4.3017.08 3.22 5.30 8.54
2.0
16.416.016.016.216.416.216.616.816.016.416.816.216.816.616.016.2
ON
xlO 2
xlO~ 3 xlO 3 xlO~ 2
xlO2
-A57-
TABLE C.23 ELECTROPHORESIS OF COLLIERY WASTE-WATER AT pH = 4.9
CONDUCTIVITY (X)
CROSS-SECTIONAL AREA OF THE ELECTROPHORETIC CELL (A")
DISTANCE TRAVELLED BY THE PARTICLES ON THE TELEVISION SCREEN (X)
CIRCUIT REVERSED
= 1 .61 10 1 ohm
= 1 .0 10~4 m2
= 28.0 10~ 2 m
MIGRATION TOWARDS THE NEGATIVE ELECTRODE
d(m)V(volt)I ( amp )R(ohm)Km)E(vplt
3.7017.01
3.215.308.53
1.99
15.215.015.214.615.214.815.214.614.214.014.814.215.015.014.614.4
TIME (
3.7516.983.205.318.54
1.99
14.615.214.814.814.414.013.814.413.613.814.214.014.013.613.413.6
3.8016.953.195.318.55
1 .98
12.411.811 .612.011 .611 .611 .812.211 .811 .612.212.011 .812.011 .611 .8
3.8516.993.205.318.55
1.99
11.612.011 .411.211 .611 .011.011.411.211.612.011 .811 .411 .811.411.0
SEC) TAKEN TO TRAVEL THETHE TELEVISION SCREEN
3.9016.913.195.308.53
1.98
13.413.013.013.814.014.214.013.613.213.813.413.613.813.213.413.8
DISTANCE
3.9516.963.205.308.53
1 .99
14.614.815.214.814.414.215.015.214.214.614.815.014.214.614.414.4
ON
xlO 2
xlO~ 3xlO 3xlO~ 2
xlO2
-A58-
TABLE C.24 ELECTROPHORESIS OF COLLIERY WASTE-WATER AT pH = 4.9
CONDUCTIVITY (X) =1.61 1C" 1 ohnf 1 m~ l
CROSS-SECTIONAL AREA OF _4
THE ELECTROPHORETIC CELL (A) = 1.0 10 m
DISTANCE TRAVELLED BY THE
PARTICLES ON THE TELEVISION = 28.0 10~2 m
SCREEN (X)
CIRCUIT REVERSED
MIGRATION TOWARDS THE POSITIVE ELECTRODE
d(m)V(volt) I ( amp ) R(ohm) l(m)E(volt m' 1 )
;
4.0517.02 3.21 5.30 8.54
1 .99
16.817.217.417.017.416.816.616.616.417.016.816.617.215.815.615.8
TIME (
4.1017.06
3.22 5.30 8.53
2.0
14.414.213.813.613.214.814.214.013.213.813.614.014.414.413.214.6
4.1516.94 3.19 5.31 8.55
1 .98
12.813.013.212.612.012.012.812.612.412.012.212.211 .811 .612.011 .8
4.2016.97 3.20 5.308.54
1 .99
11 .611 .811.211.411 .611 .011 .411 .611 .011 .211 .211 .811 .611 .812.012.0
SEC) TAKEN TO TRAVEL THE
THE TELEVISION SCREEN.
4.2517.04 3.21 5.31 8.55
1 .99
13.413.213.013.613.613.412.813.213.213.012.613.213.413.212.813.0
DISTANCE
4.3017.09 3.22 5.31 8.55
2.0
14.814.214.014.214.014.214.813.814.013.813.614.214.414.814.814.2
ON
xlO 2
xlO~ 3 xlO 3 xlO~ 2
xlO2
-A 5 9-
TABLE C.25 ELECTROPHORESIS OF COLLIERY WASTE-WATER AT pH = 4.0
CONDUCTIVITY (X)CROSS-SECTIONAL AREA OF THE ELECTROPHORETIC CELL (A)DISTANCE TRAVELLED BY THE PARTICLES ON THE TELEVISION SCREEN (X)
= 1 .68 10 l ohm I m— 4 7
= 1.0 10 m
= 28.0 10~ 2 m
MIGRATION TOWARDS THE NEGATIVE ELECTRODE
d(m)V(volt) I ( amp ) R(ohm) Km)E(volt m' 1 )
3.7016.96
3.33 5.10 8.56
1.98
15.015.816.216.415.615.815.416.214.814.614.214.415.814.414.814.6
TIME (
3.7516.98 3.33 5.10 8.57
1 .98
14.213.615.214.613.013.614.813.412.413.813.414.013.213.413.813.6
3.8016.95 3.33 5.09 8.55
1 .98
12 .813.412.612.412.813.212.613.012.012.613.012.412.812.612.212.4
3.8516.99 3.33 5.10 8.57
1 .98
12.412.611 .011 .811 .612.011.612.414.011 .611 .411.211 .012.211 .811.4
SEC) TAKEN TO TRAVEL THETHE TELEVISION SCREEN
3.9016.94 3.32 5.10 8.57
1.98
13.413.213.813.213.614.213.813.415.014.213.613.013.213.013.413.8
DISTANCE
3.9516.96 3.33 5.10 8.56
1 .98
14.614.014.815.614.614.214.814.4
14.814.414.614.014.614.414.2
ON
xlO 2
xlO~ 3 xlO 3 xlO~ 2
xlO2
-A60-
TABLE C.26 ELECTROPHORESIS OF COLLIERY WASTE-WATERAT pH = 4.0
CONDUCTIVITY (X)
CROSS-SECTIONAL AREA OF THE ELECTROPHORETIC CELL (A)
DISTANCE TRAVELLED BY THE PARTICLES ON THE TELEVISION SCREEN (X)
= 1 .68 10 ohm
= 1 .0 10~4 m2
28.0 10~2 m
m
MIGRATION TOWARDS THE POSITIVE ELECTRODE
d(m)V(volt)I ( amp )R(ohm)Km)E(volt m- 1 )
4.0516.93
3.325.108.57
1.98
15.215.816.015.616.015.415.216.015.415.615.215.016.215.815.415.2
TIME (
4.1016.973.335.108.56
1.98
14.014.615.214.814.014.814.414.614.414.214.814.614.214.814.014.4
4.15
16.943.325.108.57
1 .98
13.413.213.813.213.613.413.213.813.013.813.413.413.213.2
13.013.6
4.2016.993.335.108.57
1 .98
12.813.013.012.612.012.412.612.212.012.412.212.812.613.012.812.4
SEC) TAKEN TO TRAVEL THE
THE TELEVEISION SCREEN
4.2516.953.335.098.55
1.98
15.615.216.216.015.615.815.415.215.815.215.416.215.815.416.015.6
DISTANCE
4.30 xlO 216.983.33 xlO~ 35.10 xlO 38; 57 xlO" 2
1.98 xlO 2
16.817.217.016.617.016.416.015.816.616.216.816.415.816.617.016.2
ON
-A61-
TABLE C.27 ELECTROPHORESIS OF COLLIERY WASTE-WATER AT pH = 4.0
CONDUCTIVITY (X)CROSS -SEC RIONAL AREA OF THE ELECTROPHORETIC CELL (A)DISTANCE TRAVELLED BY THE PARTICLES ON THE TELEVISION SCREEN (X)
CIRCUIT REVERSED
= 1 .68 10 ohm m
=1.0 10~4 m2
= 28.0 10~ 2 m
MIGRATION TOWARDS THE NEGATIVE ELECTRODE
d(m)V(volt)I ( amp )R(ohm)Km)E(volt m-1)
3.7017.043.345.108.57
1 .99
14.013.813.614.014.213.813.413.213.614.213.813.213.213.613.813.4
TIME (
3.7517.073.355.108.56
1.99
13.213.813.613.013.413.213.013.814.014.413.813.413.013.613.213.2
3.8017.053.345.108.58
1 .99
12.211 .611 .412.011 .611 .211 .811 .611 .411 .812 .012 .211 .411.611 .811 .20
3.8517.063.355.098.56
1.99
11 .611.011 .011.412.011.411.811.211.211.411 .811.211 .611.411 .011.4
SEC) TAKEN TO TRAVEL THETHE TELEVISION SCREEN
3.9017.093.355.108.57
1 .99
13.212 .812.613.013.013.813.413.012.613.213.612.812.613.212.813.4
DISTANCE
3.9517.113.365.098.56
2.0
14.813.814.013.413.614.414.614.014.414.214.814.014.614.213.813.6
ON
xlO 2
xlO~ 3xlO 3xlO~ 2
xlO2
-A62-
TABLE C.28 ELECTROPHORESIS OF THE COLLIERY WASTE-WATER AT pH = 4.0
CONDUCTIVITY (\)CROSS-SECTIONAL AREA OF THE ELECTROPHORETIC CELL (A)DISTANCE TRAVELLED BY THE PARTICLES ON THE TELEVISION SCREEN (X)
CIRCUIT REVERSED
= 1 .68 10 ohm m
=1.0 10~ 4 m2
= 28.0 10~ 2 m
MIGRATION TOWARDS THE POSITIVE ELECTRODE
d(m)V(volt) I ( amp ) R(ohm) Km)E(volt m" 1 )
4.0517.04 3.34 5.10 8.57
1.99
16.615.816.015.816.216.015.615.415.615.216.216.015.215.415.415.6
TIME (
4.1017.09 3.35 5.09 8.56
2.0
14.013.613.213.813.014.213.213.013.813.613.014.013.413.613.213.4
SEC ) TAKEN
4.1517.10 3.35 5.10 8.58
1 .99
11 .812.212 .011 .611 .611 .211 .411.212.011 .812.211 .811 .011 .411.211 .6
4.2017.12 3.36 5.10 8.56
2.0
11.611.011.211 .211 .011 .410.810.611.011.410.810.810.611.011.211.6
TO TRAVEL THE
4.2517.13 3.36 5.10 8.57
2.0
12.813.012.412.011.811 .612.011 .411 .612.411.811 .412.012.011 .611.4
DISTANCE
4.30 xlO 217.15 3.36 xlO~ 3 5.10 xlO 3 8.58 xlO~ 2
2.0 xlO2
14.614.013.613.213.613.014.013.813.414.213.813.413.413.213.813.6
ONTHE TELEVISION SCREEN
-A63-
TABLE C.29 ELECTROPHORESIS OF COLLIERY WASTE-WATER AT pH = 2.7
CONDUCTIVITY (A )
CROSS- SECTIONAL AREA OF THE ELECTROPHORETIC CELL (A)DISTANCE TRAVELLED BY THE PARTICLES ON THE TELEVISION SCREEN (X)
= 2.58 10 ohm A m-4 2 = 1.0 10 m
= 28.0 10~ 2 m.
MIGRATION TOWARDS THE NEGATIVE ELECTRODE
d(m)V(volt)I ( amp )R ( ohm )Km)E(volt m-1)
3.7016.524.993.318.54
1.93
14.214.014.013.614.213.813.413.013.813.614.013.414.213.813.813.6
TIME (
3.7516.554.993.318.56
1 .93
13.413.613.012.812.813.213.013.213.013.413.613.413.612 .612.813.4
SEC ) TAKEN
3.8016.564.993.328.56
1 .93
12.412.812.412.612 .012.212.212.612.812.412.012.412.212.612.412.0
3.8516.585.003.328.56
1 .94
11 .811 .612 .012.211 .811.411 .811.812.011 .211.611.411.411 .811 .611.2
TO TRAVEL THE
3.9016.514.983.328.55
1.93
12.813.213.013.413.213.813.613.813.212.813.613.613.414.013.812.8
DISTANCE
3.95 xlO 216.544.99 xlO~ 33.31 xlO 38.55 xlO~ 2
1.93 xlO2
13.813.614.014.614.214.814.414.013.413.814.214.013.613.414.614.4
ON
THE TELEVISION SCREEN
-A64-
TABLE C.30 ELECTROPHORESIS OF COLLIERY WASTE-WATER AT pH = 2.7
CONDUCTIVITY (X)
CROSS-SECTIONAL AREA OF THE ELECTROPHORETIC CELL (A)
DISTANCE TRAVELLED BY THE PARTICLES ON THE TELEVISION SCREEN (X)
= 2.58 10 ohm m
-4 2= 1.0 10 m
= 28.0 10~ 2 m
MIGRATION TOWARDS THE POSITIVE ELECTRODE
d(m)
V(volt)
I ( amp )R(ohm)
Km)E(volt
4.25
16.52
4.99
3.31
8.54
1 .93
14.6
14.415.2
14.814.6
14.2
14.6
15.015.2
14.2
14.6
14.4
14.8
15.0
14.4
14.8
TIME (
4.10
16.564.99
3.32
8.56
1 .93
13.4
13.0
13.6
13.413.2
14.0
14.2
13.8
13.613.2
13.8
14.2
13.4
13.6
14.0
13.4
4.15
16.534.99
3.31
8.55
1 .93
12 .8
13.012 .6
12.212.6
12.412 .8
12.412.2
12.6
12.8
12 .2
12.2
12.6
12.4
12.6
4.20
16.58
5.003.32
8.56
1 .94
12.0
11 .811 .6
11.211 .8
11 .412.0
11 .611 .4
11.2
11 .8
11 .012.0
11.6
11 .4
11.2
SEC) TAKEN TO TRAVEL THE
THE TELEVISION SCREEN
4.25
16.544.99
3.31
8.55
1.93
14.4
14.814.0
14.814.2
14.615.0
14.614.2
14.4
15.0
14.614.4
14.814.2
14.4
DISTANCE
4.30 xlO
16.57
5.00 xlO~ 3
3.31 xlO3
8.55 xlO~ 2
1.94 xlO2
15.8
15.6
16.0
15.416.2
15.615.2
16.0
16.2
15.4
15.2
15.8
15.6
15.2
15.4
15.0
ON
-A65-
TABLE C.31 ELECTROPHORESIS OF COLLIERY WASTE-WATER AT pH = 2.7
CONDUCTIVITY (X) = 2.58 10 ohm mCROSS-SECTIONAL AREA OF THE -4 2 ELECTROPHORETIC CELL (A) - l.U 1U m
DISTANCE TRAVELLED BY THE ~ PARTICLES ON THE TELEVISION = 28.0 10 m SCREEN (X)
CIRCUIT REVERSED
MIGRATION TOWARDS THE NEGATIVE ELECTRODE
d(m)V(volt) I ( amp ) R ( ohm ) Km)E(volt m" 1 )
3.7016.55 4.99 3.31 8.55
1.93
13.813.412 .813.012.813.212.612.412.613.013.412.413.213.812.412.6
TIME ( SEC
3.7516.59 5.00 3.32 8.56
1 .94
12.612.012.413.212.812.612.213.013.212.412.812.212.612.013.012.6
) TAKEN
3.8016.52 4.99 3.31 8.54
1 .93
11.211 .611 .211.811 .010.810.611 .211 .411 .411.610.810.811 .010.610.6
3.8516.54 4.99 3.31 8.55
1.93
11 .010.410.210.610.410.011 .210.811.211 .610.810.210.410.610.410.4
TO TRAVEL THE
3.9016.56 4.99 3.32 8.56
1.93
12.412.6
11 .811.612.012.412.211 .812.612.212.011.611 .812.012.012.4
DISTANCE
3.9516.62 5.00 3.32 8.57
1.94
13.613.814.013.413.412.812 .612.812.413.612.413.812.612 .612.212.2
ON
xlO 2
xlO~ 3 xlO3 xlO" 2
xlO 2
THE TELEVISION SCREEN
-A66-
TABLE C.32 ELECTROPHORESIS OF COLLIERY WASTE-WATER AT pH = 2.7
CONDUCTIVITY (X)
CROSS-SECTIONAL AREA OFTHE ELECTROPHORETIC CELL (A)
DISTANCE TRAVELLED BY THE PARTICLES ON THE TELEVISION SCREEN (X)
= 2.58 10 ohm=1.0 10~ 4 m2
= 28.0 10~ 2 m
m
MIGRATION TOWARDS THE POSITIVE ELECTRODE
d(m)V(volt)I ( amp )R(ohm)Km)E(volt m~l
4.0516.635.003.338.58
1 .94
15.816.015.415.015.415.615.215.615.015.815.415.416.015.815.615.4
TIME (
4.1016.655.013.328.57
1 .94
14.213.813.613.413.013.813.413.214.014.013.214.213.613.213.413.0
SEC) TAKEN
4.1516.625.003.328.58
1 .94
11 .411 .011 .611.211 .011 .811 .411 .411 .811 .610.810.811 .211.211 .011 .4
4.2016.66
5.013.338.58
1 .94
10.610.210.410.210.810.611 .010.411.010.610.610.211 .010.810.810.6
TO TRAVELL THE
4.2516.564.993.328.56
1.93
12.412.012.011 .811 .611 .812.411 .411 .611 .611 .212.012.212.411.812.0
DISTANCE
4.30 xlO 216.595.00 xlO~ 33.32 xlO 38.56 xlO~ 2
1.94 xlO 2
12.813.413.613.613.013.213.413.013.813.613.013.013.213.413.613.6
ONTHE TELEVISION SCREEN
-A67-
TABLE C.33 ELECTROPHORESIS OF COLLIERY WASTE-WATER AT pH = 1.9
CONDUCTIVITY (A)
CROSS-SECTIONAL AREA OF THE ELECTROPHORETIC CELL (A)
DISTANCE TRAVELLED BY THE PARTICLES ON THE TELEVISION SCREEN (X)
= 7.40 10 ohm -4 ?= 1 .0 10 m
= 28.0 10~ 2 m
m
MIGRATION TOWARDS THE NEGATIVE ELECTRODE
d(m)V(volt)I ( amp )R(ohm)Km)E(volt
m"-1-
3.7010.92
9.411 .168.59
1 .27
18.018.218.417.818.017.617.217.417.817.418.217.618.417.417.617.6
TIME (
3.7510.959.441 .168.58
1 .28
16.617.216.817.016.616.416.817.416.816.616.216.416.816.617.016.6
SEC ) TAKEN
3.8010.969.441 .168.59
1 .28
15.815.416.216.015.815.415.615.615.215.415.815.816.215.616.015.4
3.8510.989.451 .168.60
1 .28
14.614.614.614.013.613.813.814.213.613.413.414.814.614.413.613.8
TO TRAVEL THE
3.9010.959.441.168.58
1.28
14.614.815.215.214.615.414.814.815.215.615.614.414.814.415.215.4
DISTANCE
3.9510.979.451 .168.59
1 .28
16.216.616.416.416.017.216.817.017.416.816.616.016.216.216.616.4
ON
xlO 2
xlO~ 3xlO 3xlO~ 2
xlO2
THE TELEVISION SCREEN
-A68-
TABLE C . 34 ELECTROPHORESIS OF COLLIERY WASTE -WATER AT pH = 1.9
CONDUCTIVITY (X)
CROSS-SECTIONAL AREA OF THE ELECTROPHORETIC CELL (A)
DISTANCE TRAVELLED BY THE PARTICLES ON THE TELEVISION SCREEN (X)
= 7.40 10 ohm m
= 1 .0 10~4 m2
= 28.0 10~ 2 m
MIGRATION TOWARDS THE POSITIVE ELECTRODE
d(m)V(volt) I ( amp ) R ( ohm ) Km)E(volt
rrT-1-
4.0510.94
9.42 1 .16 8.59
1 .27
16.816.617.217.416.817.217.817.816.617.216.417.818.017.416.417.4
TIME (
4.1010.96 9.44 1 .16 8.59
1 .28
15.816.216.616.617.016.015.615.615.415.417.217.016.016.216.415.8
SEC ) TAKEN
4.1510.93
9.421 .16 8.59
1 .27
15.414.814.615.215.214.614.415.414.814.414.815.615.414.814.614.6
4.2010.97 9.45 1 .16 8.59
1 .28
13.814.214.614.613.814.014.214.013.613.614.614.814.613.814.014.0
TO TRAVEL THE
4.2510.98 9.46 1 .16 8.59
1 .28
14.815.214.614.615.415.415.816.216.015.815.614.815.215.415.215.6
DISTANCE
4.30 xlO 210.99 9.47 xlO~ 3 1.16 xlO 3 8.59 xlO~ 2
1.28 xlO 2
15.415.816.615.816.415.416.616.817.217.016.816.416.817.217.417.0
ON
THE TELEVISION SCREEN
-A69-
TABLE C.35 ELECTROPHORESIS OF COLLIERY WASTE-WATER AT pH = 1.9
CONDUCTIVITY (X)
CROSS-SECTIONAL AREA OF THE ELECTROPHORETIC CELL (A)
DISTANCE TRAVELLED BY PARTICLES ON THE TELEVISION SCREEN (X)
= 7.40 10 ohm-4 ?
= 1 .0 10 m
= 28.0 10~ 2 m
m
CIRCUIT REVERSED
MIGRATION TOWARDS THE NEGATIVE ELECTRODE
d(m) V(volt) I ( amp ) R(ohm) Km)E(volt m" 1 )
3.70 10.89 9.39 1.16 8.58
1 .27
17.417.617.017.217.617.617.817.017.217.217.817.417.817.217.417.4
TIME (
3.75 10.90
9.40 1 .16 8.58
1 .27
16.816.816.416.616.417.617.416.216.216.016.816.216.416.617.617.2
3.80 10.87
9.38 1 .16 8.58
1 .27
15.415.216.215.816.415.015.616.416.015.415.615.215.816.016.416.2
3.85 10.91
9.41 1 .16 8.58
1 .27
15.214.815.614.615.415.414.814.614.814.414.215.615.214.014.214.0
SEC ) TAKEN TO TRAVEL THE
THE TELEVISION SCREEN
3.90 10.84 9.34 1.16 8.59
1 .26
15.415.215.214.814.215.214.614.214.815.414.614.414.414.814.214.4
DISTANCE
3.95 xlO 2 10.87 9.28 xlO~ 3 1.16 xlO 3 8.58 xlO~ 2
1.27 xlO2
15.815.615.615.216.416.615.816.616.815.215.416.616.216.215.816.4
ON
-A70-
TABLE C.36 ELECTROPHORESIS OF COLLIERY WASTE-WATER AT pH = 1.9
CONDUCTIVITY (X)
CROSS-SECTIONAL AREA OFTHE ELECTROPHORETIC CELL (A)
DISTANCE TRAVELLED BY THE PARTICLES ON THE TELEVISION SCREEN (X)
CIRCUIT REVERSED
= 7.40 10 ohm m= 1 .0 10~4 m~ 2
= 28.0 10~2 m
MIGRATION TOWARDS THE POSITIVE ELECTRODE
d(m)V(volt)I ( amp )R(ohm)Km)E(volt
4.0510.869.361 .168.59
1 .26
17.216.616.617.016.816.817.617.417.617.417.416.817.217.016.817.2
TIME
4.1010.889.381 .168.58
1 .27
15.416.815.215.215.615.416.616.215.815.615.816.016.216.016.416.4
4.1510.919.411 .168.58
1 .27
14.614.815.215.214.415.615.414.815.615.414.414.814.814.214.614.6
4.2010.899.391 .168.58
1 .27
13.613.814.214.414.613.813.413.413.214.213.214.014.013.613.414.2
(SEC) TAKEN TO TRAVEL THE
THE TELEVISION SCREEN
4.2510.879.38
1 .168.58
1 .27
15.415.615.214.814.615.414.814.414.814.615.615.614.415.214.614.4
DISTANCE
4.30 xlO 210.91
9.41 xlO~ 31.16 xlO 38.58 xlO~ 2
1.27 xlO2
16.216.015.415.816.416.016.215.616.415.615.615.415.215.215.816.0
ON
-A71-
ELECTROPHORESIS OF COLLIERY WASTE-WATER USING
APPENDIX D
-A72-
TABLE D.1 ELECTROPHORESIS OF COLLIERY WASTE-WATER AT pH = 8.8
CONDUCTIVITY (X)CROSS-SECTIONAL AREA OF THE ELEC TROPHORE TIC CELL (A)DISTANCE TRAVELLED BY THE PARTICLES ON THE TELEVISION SCREEN (X)
= 1 .34 10
=1.0 10~4
= 28.0 10~ 2
ohm
2m
m
MIGRATION TOWARDS THE POSITIVE ELECTRODE
d(m)V(volt)I ( amp )R(ohm)Km)E(volt m-1)
3.7020.51
3.196.438.62
2.38
17.216.817.016.616.217.417.616.416.616.817.217.016.416.216.616.4
TIME (
3.7520.503.196.438.61
2.38
16.215.815.615.416.416.015.815.216.016.415.215.416.015.415.615.4
3.8020.53
3.206.428.60
2.39
15.615.015.015.215.415.615.814.815.415.214.614.815.215.614.814.8
3.8520.553.206.428.61
2.39
14.815.014.214.014.014.414.614.214.414.614.814.214.215.214.815.0
SEC) TAKEN TO TRAVEL THE
THE TELEVISION SCREEN
3.9020.533.196.448.62
2.38
15.615.815.416.016.415.816.215.615.415.616.015.215.215.415.815.4
DISTANCE
3.9520.573.206.438.61
2.39
16.216.016.015.615.816.416.615.816.616.816.616.416.215.616.216.4
ON
xlO~ 2
xlO~ 3xlO 3xlO~ 2
xlO2
lm
-A73-
TABLE D.2 ELECTROPHORESIS OF COLLIERY WASTE -WATER AT pH = 8.8
CONDUCTIVITY (X)CROSS-SECTIONAL AREA OF THE ELECTROPHORETIC CELL (A)
DISTANCE TRAVELLED BY THE PARTICLES ON THE TELEVISION SCREEN (X)
= 1 .34 10 ohm m
= 1 .0 10~4 m2
= 28.0 10~ 2 m
MIGRATION TOWARDS THE NEGATIVE ELECTRODE
d(m)V(volt)I ( amp )R(ohm)Km)E(volt m-1)
4.0520.553.196.448.63
2.38
18.217.817.618.017.618.217.417.017.417.218.017.817.217.417.617.8
TIME (
4.1020.523.196.438.62
2.38
16.817.217.016.617.216.416.216.617.016.816.816.416.616.216.416.4
4.1520.543.196.448.63
2.38
15.215.816.016.215.615.415.415.215.616.015.816.215.816.416.015.4
4.2020.56
3.206.438.61
2.39
15.014.614.415.214.214.814.214.414.815.014.214.615.214.414.014.0
SEC) TAKEN TO TRAVEL THE
THE TELEVISION SCREEN
4.2520.573.206.438.61
2.39
15.615.416.216.016.615.816.416.615.815.416.015.616.215.816.016.4
DISTANCE
4.30 xlO 220.58
3.20 xlO~ 36.44 xlO 38.61 xlO~2
2.39 xlO 2
16.816.417.217.016.617.617.417.416.616.417.016.817.416.417.217.0
ON
-A74-
TABLE D . 3 ELECTROPHORESIS OF COLLIERY WASTE-WATER AT pH = 8.8
CONDUCTIVITY (\ )
CROSS-SECTIONAL AREA OF THE ELECTROPHORETIC CELL (A)DISTANCE TRAVELLED BY THE PARTICLES ON THE TELEVISION SCREEN (X)
CIRCUIT REVERSED
= 1 .34 10
=1.0 10~ 4
= 28.0 10~ 2
ohm m m2
m
MIGRATION TOWARDS THE POSITIVE ELECTRODE
d(m)V(volt)I ( amp )R(ohm)Km)E(volt m" 1 )
3.7020.523.196.438.62
2.38
16.817.417.618.018.217.818.417.017.217.617.817.017.416.817.618.2
TIME (
3.7520.543.196.448.63
2.38
17.417.816.816.616.416.016.816.217.226.816.216.416.016.616.416.2
3.8020.56
3.196.458.64
2.38
16.226.015.615.215.815.015.816.015.616.215.815.215.015.415.416.0
3.8520.553.196.448.63
2.38
14.814.814.013.813.614.614.214.214.614.214.214.014.414.613.814.8
SEC) TAKEN TO TRAVEL THE
THE TELEVISION SCREEN
3.9020.53
3.196.448.62
2.38
16.616.416.217.215.815.617.016.016.816.416.616.017.016.816.216.4
DISTANCE
3.9520.543.196.448.63
2.38
16.817.417.818.218.218.418.017.817.017.428.217.818.018.218.218.4
ON
xlO~ 2
xlO~ 3xlO 3xlO~ 2
xlO2
-A75-
TABLE D.4 ELECTROPHORESIS OF COLLIERY WASTE-WATER AT pH = 8.8
CONDUCTIVITY (A) =1.34 1C" 1 ohm" 1 m" 1CROSS-SECTIONAL AREA OF THE - i n 1n~4 2 ELECTROPHORETIC CELL (A) - 1 .U 1U m
DISTANCE TRAVELLED BY THEPARTICLES ON THE TELEVISION = 28.0 10 mSCREEN (X)
CIRCUIT REVERSED
MIGRATION TOWARDS THE NEGATIVE ELECTRODE
d(m)V(volt)I ( amp )R(ohm)Km)E^volt m )
4.0520.55
3.196.448.63
2.38
17.217.818.418.618.217.618.018.417.617.818.018.418.217.217.417.4
TIME (
4.1020.573.196.458.64
2.38
16.617.017.226.816.216.016.417.017.216.416.216.617.016.416.616.8
SEC ) TAKEN
4.1520.523.196.438.62
2.38
15.215.615.816.016.015.415.616.215.015.215.015.615.816.215.415.4
4.2020.543.196.448.63
2 .38
13.613.814.214.013.814.814.614.214.414.014.814.414.614.814.214.4
TO TRAVEL THE
4.2520.543.196.448.62
2.38
14.815.215.616.215.815.014.615.415.415.614.816.016.215.815.615.2
DISTANCE
4.30 xlO 220.553.19 xlO~ 36.44 xlO 38.63 xlO~ 2
2.38 xlO 2
16.216.616.816.015.816.417.217.416.817.417.216.616.416.217.216.8
ON
THE TELEVISION SCREEN
-A76-
TABLE D.5 ELECTROPHORESIS OF COLLIERY WASTE-WATER AT pH = 7.0
CONDUCTIVITY (X)CROSS-SECTIONAL AREA OF THE ELECTROPHORETIC CELL (A)
DISTANCE TRAVELLED BY THE PARTICLES ON THE TELEVISION SCREEN (X)
= 1 .39 10
= 1 .0 10~4
= 28.0 10~ 2
ohm2m
m
MIGRATION TOWARDS THE POSITIVE ELECTRODE
d(m)V(volt) I ( amp ) R(ohm) Km)E(volt m- 1 )
3.7020.28 3.28 6.18 8.59
2.36
15.215.014.614.214.615.214.814.414.614.815.415.214.415.015.414.8
TIME (
3.7520.32 3.29 6.18 8.59
2.37
14.414.013.813.614.214.013.413.814.614.213.613.414.413.814.214.6
3.8020.26 3.28 6.18 8.59
2.36
14.014.213.813.614.213.213.414.013.213.013.613.413.213.814.213.6
3.8520.29
3.28 6.19 8.60
2.36
13.412.812.413.012.612.812.213.612.212.613.012.812.812.412.612.4
SEC) TAKEN TO TRAVEL THE
THE TELEVISION SCREEN
3.9020.28 3.28 6.18 8.59
2.36
14.014.615.214.614.815.014.414.214.615.014.414.814.215.214.814.4
DISTANCE
3.9520.25 3.27 6.19 8.60
2.35
15.615.816.216.414.815.415.015.816.016.215.615.415.216.415.615.0
ON
xlO~ 2
xlO~ 3 xlO 3 xlO~ 2
xlO 2
m
-A77-
TABLE D . 6 ELECTROPHORESIS OF COLLIERY WASTE -WATER AT pH = 7.0
CONDUCTIVITY (X)CROSS-SECTIONAL AREA OF THE ELECTROPHORETIC CELL (A)DISTANCE TRAVELLED BY THE PARTICLES ON THE TELEVISION SCREEN (X)
= 1 .39 10 ohm m1.0 10~4 m2
= 28.0 10-2
MIGRATION TOWARDS THE NEGATIVE ELECTRODE
d(m)V(volt)I ( amp )R(ohm)Km)E(volt m-1)
4.0520.26
3.286.188.59
2.36
15.215.816.216.016.415.615.415.615.216.015.815.416.015.815.615.2
TIME (
4.1020.273.286.188.60
2 .36
14.814.215.015.414.615.014.414.615.415.014.814.214.614.814.614.4
SEC) TAKEN
4.1520.29
3.286.198.60
2.36
13.613.814.214.413.613.414.013.614.014.213.413.613.614.013.813.4
4.2020.303.286.198.60
2.36
12.412.213.012.613.213.212 .812.213.013.212 .612.612 .812.412.212.4
TO TRAVEL THE
4.2520.24
3 .276.198.60
2.35
14.814.414.213.614.013.814.614.013.814.213.814.414.014.013.614.6
DISTANCE
4.30 xlO 220.253.27 xlO~ 36.19 xlO 38.60 xlO~ 2
2.35 xlO 2
14.614.013.814.215.015.415.816.215.414.614.815.615.816.215.415.6
ONTHE TELEVISION SCREEN
-A78-
TABLE D.7 ELECTROPHORESIS OF COLLIERY WASTE -WATER AT pH = 7.0
CONDUCTIVITY (X)CROSS-SECTIONAL AREA OF THE ELECTROPHORETIC CELL (A)DISTANCE TRAVELLED BY THE PARTICLES ON THE TELEVISION SCREEN (X)
CIRCUIT REVERSED
= 1 .39 10 ohm m-4 2 = 1.0 10 m
= 28.0 10 m
MIGRATION TOWARDS THE POSITIVE ELECTRODE
d(m)V(volt) I ( amp ) R(ohm) Km)E(volt m-1)
3.7020.35 3.29 6.19 8.60
2.37
14.815.415.214.814.615.014.814.415.414.615.014.614.415.215.214.8
TIME
3.7520.36 3.29 6.19 8.60
2.37
13.814.214.414.013.614.014.214.814.614.814.414.614.413.814.013.6
3.8020.34 3.29 6.18 8.60
2.37
13.213.013.013.613.813.413.213.614.014.213.613.413.013.213.813.4
3.8520.36 3.29 6.19 8.60
2 .37
13.612.813.013.212.612.412.813.212.212.012.412.212 .612.412.412.8
(SEC) TAKEN TO TRAVEL THE
THE TELEVISION SCREEN
3.9020.32 3.29 6.18 8.59
2.37
14.214.614.013.813.614.414.214.814.414.014.213.814.614.813.614.4
DISTANCE
3.95 xlO 220.35 3.29 xlO~ 3 6.19 xlO3 8.60 xlO~ 2
2.37 xlO 2
14.814.614.215.015.414.415.615.815.615.014.814.415.215.214.614.2
ON
-A79-
TABLE D.8 ELECTROPHORESIS OF COLLIERY WASTE-WATER AT pH = 7.0
CONDUCTIVITY (X) = 1.39 lo" 1 ohm" 1CROSS-SECTIONAL AREA OF THE - 1 n 1 D~4 2 ELECTROPHORETIC CELL (A) ~ U mDISTANCE TRAVELLED BY THE _ ? PARTICLES ON THE TELEVISION = 28.0 10 m SCREEN (X)
CIRCUIT REVERSED
MIGRATION TOWARDS THE NEGATIVE ELECTRODE
d(m) V(volt) I ( amp ) R(ohm) Km) E(volt
4.05 20.35 3.29 6.19 8.60
2.37
14.614.815.215.415.014.415.615.215.014.814.415.415.614.615.215.4
TIME (
4.10 20.39 3.30 6.18 8.59
2.37
14.614.614.415.213.814.214.014.413.813.614.014.413.613.413.813.4
SEC) TAKEN
4.15 20.37 3.29 6.19 8.61
2.37
13.413.613.213.013.212.812.613.413.813.613.012.812.413.213.413.6
4.20 20.38 3.29 6.19 8.61
2.37
12.212.011 .812.413.012.811 .612.011 .812.212.212.011 .612.412.411 .6
TO TRAVEL THE
4.25 20.35 3.29 6.19 8.60
2.37
14.214.614.215.014.415.214.814.614.415.215.014.814.414.614.614.8
DISTANCE
4.30 20.38 3.29 6.19 8.61
2.37
14.814.214.214.615.015.615.415.816.216.416.415.615.816.216.016.0
ON
xlO~ 2
xlO~ 3 xlO 3 xlO~2
xlO2
THE TELEVISION SCREEN
-A80-
TABLE D.9. ELECTROPHORESIS OF THE COLLIERY WASTE-WATER AT pH = 6.0
CONDUCTIVITY (X)CROSS-SECTIONAL AREA OF THE ELECTROPHORETIC CELL (A)DISTANCE TRAVELLED BY THE PARTICLES ON THE TELEVISION SCREEN (X)
= 1 .50 10 ohm m-4. 9
= 1 .0 10 m
= 28.0 10" 2 m
MIGRATION TOWARDS THE POSITIVE ELECTRODE
d(m) V(volt) I ( amp ) R(ohm) Km)E(volt m- 1 )
3.70 19.17 3.34 5.74 8.61
2.23
14.414.815.015.215.014.614.614.815.414.414.615.415.014.815.215.2
TIME (
3.75 19.15 3.34 5.73 8.60
2.23
14.014.214.013.813.614.013.413.413.613.212.813.013.613.213.013.8
3.80 19.11 3.33 5.74 8.61
2.22
12.812.212.212.612.812.012.412.413.012.612.012.412.212.813.013.0
3.85 19.09 3.33 5.73 8.60
2.22
12.011 .811 .412.211 .611 .011 .411 .811 .811 .011 .612.011 .411 .211 .211 .0
SEC) TAKEN TO TRAVEL THE
THE TELEVISION SCREEN
3.90 19.10 3.33 5.74 8.60
2.22
12.813.413.213.012.812.613.213.013.412.613.013.412.412.612.412.8
DISTANCE
3.95 xlO 2 19.11 3.33 xlO~ 3 5.74 xlO 3 8.61 xlO~ 2
2.22 xlO2
13.213.814.214.014.414.213.613.813.414.414.813.613.214.814.013.6
ON
-A81-
TABLE D.10 ELECTROPHORESIS OF COLLIERY WASTE-WATER AT pH = 6.0
CONDUCTIVITY (X) = 1.50 10 ohm mCROSS -SECTIONAL AREA OF THE , _ .. _-4 2 ELECTROPHORETIC CELL (A) m
DISTANCE TRAVELLED BY ? PARTICLES ON THE TELEVISION = 28.0 10 m SCREEN (X)
MIGRATION TOWARDS THE NEGATIVE ELECTRODE
d(m)
V(volt) I ( amp ) R(ohm) Km)E(volt m-1)
4.0519.08 3.33 5.73 8.59
2.22
14.815.215.214.615.014.814.414.214.414.815.014.814.614.614.2
14.6
TIME (
4.1019.12 3.335.74 8.61
2 .22
14.013.613.613.413.814.214.413.813.613.413.414.014.214.414.413.6
4.1519.07 3.32 5.74 8.62
2.21
12.813.413.012.612.412.213.212.012.613.212.412.813.412.012.213.0
4.2019.11 3.33 5.74 8.61
2.22
12 .411 .812.011 .411 .611 .812.212.011 .811 .612.211.611 .411.411 .611 .8
SEC) TAKEN TO TRAVEL THE
THE TELEVISION SCREEN
4.2510.09 3.33 5.73 8.60
2.22
12.813.213.012.613.413.413.613.213.012.812.613.013.213.013.613.6
DISTANCE
—————————————— ?j- 4.30 xlO~
19.12 3.33 xlO~ 3 5.74 xlO 3 8.61 xlO~ 2
2.22 xlO 2
13.613.814.014.413.414.214.614.214.614.014.213.814.013.613.614.0
ON
-A82-
TABLE D.ll ELECTROPHORESIS OF COLLIERY WASTE-WATER AS pH = 6.0
CONDUCTIVITY (X) = 1.50 10CROSS-SECTIONAL AREA OF THE , n -4 ELECTROPHORETIC CELL (A) ~ U UDISTANCE TRAVELLED BY THE PARTICLES ON THE TELEVISION = 28.0 10 SCREEN (X)
CIRCUIT REVERSED
ohm m2
m
MIGRATION TOWARDS THE POSITIVE ELECTRODE
d(m)V(volt)I ( amp )R(ohm)Km)E(volt m-1)
3.7019.113.335.748.61
2.22
14.614.415.415.015.414.815.214.214.814.214.615.215.414.215.014.4
TIME (
3.7519.083.335.738.59
2.22
13.813.614.014.213.413.013.214.213.413.214.013.614.213.813.013.8
SEC) TAKEN
3.8019,12
3.335.738.61
2.22
12.012 .613.213.012.812.212.413.012.412.812.812.212.612.412.412.2
3.8519.143.345.738.60
2.23
11.811 .611 .012.011.211 .811.412.212.211 .411 .211 .811.611 .412.011.2
TO TRAVEL THE
3.9019.113.335.748.61
2.22
12 .613.213.012.813.613.813.012.813.213.413.013.613.813.412.613.2
DISTANCE
3.9519.163.345.738.60
2.23
13.814.214.014.614.214.814.614.414.014.614.814.414.213.814.414.2
ON
xlO~ 2
xlO~ 3xlO 3xlO~ 2
xlO2
THE TELEVISION SCREEN.
m
-A83-
TABLE D.I2 ELECTROPHORESIS OF COLLIERY WASTE-WATER AT pH = 6.0
CONDUCTIVITY (X)
CROSS-SECTIONAL AREA OF THE ELECTROPHORETIC CELL (A)DISTANCE TRAVELLED BY THE PARTICLES ON THE TELEVISION SCREEN (X)
CIRCUIT REVERSED
= 1 .50 10 ohm m
=1.0 10"4 m2
= 28.0 10~ 2 m
MIGRATION TOWARDS THE NEGATIVE ELECTRODE
d(m) V(volt) I ( amp ) R(ohm) Km)E(volt m- 1 )
4.05 19.16
3.34 5.74 8.60
2.23
13.614.014.213.813.814.414.013.614.414.614.014.614.214.214.814.8
TIME (
4.10 19.17 3.34 5.74 8.61
2.23
14.213.813.613.213.012.813.013.414.013.613.413.213.613.814.213.6
4.15 19.08 3.33 5.73 8.59
2.22
12.813.212.612.413.613.413.012.612.412.212.212.813.413.213.013.0
4.20 19.15 3.34 5.73 8.60
2.23
11 .211 .611 .612.212 .011 .011 .811 .411 .811 .011 .211 .411 .412.011 .612.0
SEC) TAKEN TO TRAVEL THETHE TELEVISION SCREEN
4.25 19.08 3.33 5.73 8.59
2.22
12.813.213.412.814.414.814.613.013.814.414.613.813.614.814.413.2
DISTANCE
4.30 xlO 2 19.10 3.33 xlO~ 3 5.74 xlO 3 8.60 xlO~ 2
2.22 xlO2
14.613.814.815.215.215.014.813.814.815.414.614.614.415.214.615.0
ON
-A84-
TABLE D.I 3 ELECTROPHORESIS OF COLLIERY WASTE-WATER AT pH = 5.3
CONDUCTIVITY (X) = 1.55 10 ohm" 1 mCROSS-SECTIONAL AREA OF THE , n ., n~4 2 ELECTROPHORETIC CELL (A) U UDISTANCE TRAVELLED BY „ PARTICLES ON THE TELEVISION = 28.0 10 m SCREEN (X)
MIGRATION TOWARDS THE POSITIVE ELECTRODE
d(m)V(Volt) I ( amp ) R(ohm) Km)E(volt m" 1 )
3.7018.49 3.34 5.54 8.59
2.15
14.815.014.214.415.014.614.414.214.614.614.014.014.214.414.814.4
TIME (
3.7518.51 3.34 5.54 8.59
2.15
13.213.413.813.614.013.013.214.213.613.413.014.013.213.813.413.2
3.8018.50 3.34 5.54 8.59
2.15
12.813.012.613.413.212.412.212.012.612.212.813.212.013.013.412.4
3.8518.49 3.34 5.54 8.59
2.15
11 .812.011 .611.411 .012.011 .811 .211 .411.211.012.011 .611 .411 .011.2
SEC) TAKEN TO TRAVEL THETHE TELEVISION SCREEN
3.9018.52 3.34 5.54 8.59
2.15
12.412.612.013.013.012.212.612.812.812.412.012.613.012.412.212.2
DISTANCE
3.9518.55 3.35 5.54 8.58
2.16
13.214.014.214.013.613.413.813.013.813.614.2
13.013.413.213.613.2
ON
xlO 2
xlO~ 3 xlO 3 xlO~ 2
xlO2
-A85-
TABLE D.14 ELECTROPHORESIS OF COLLIERY WASTE-WATER AT pH = 5.3
CONDUCTIVITY (X) =1.55 lo" 1 ohm" 1 m" 1CROSS-SECTIONAL AREA OF -4 2 THE ELECTROPHORETIC CELL (A) l.U 1U mDISTANCE TRAVELLED BY THEPARTICLES ON THE TELEVISION = 28.0 10~ 2 mSCREEN (X)
MIGRATION TOWARDS THE NEGATIVE ELECTRODE
d(m)V(volt) I ( amp ) R(ohm) Km)E(volt m-1)
4.0518.51 3.34 5.54 8.59
2 .15
14.615.214.814.413.613.814.214.014.014.614.214.215.014.814.414.6
TIME (
4.1018.50 3.34 5.54 8.59
2.15
13.413.813.614.214.013.413.813.213.213.614.013.814.213.213.413.6
SEC ) TAKEN
4.1518.44 3.33 5.54 8.58
2.15
12 .612.412.813.012.412.212.613.213.012.612.812.813.212.412.212.2
4.2018.45 3.33 5.54 8.59
2.15
11.211 .611.811 .611 .411 .211 .011 .411 .611.211 .011 .811.411 .411 .211 .2
TO TRAVEL THE
4.2518.48 3.33 5.55 8.60
2.15
12.412.612.413.213.012.813.412.812.812.612.213.012.413.212.412.6
DISTANCE
4.3018.49 3.34 5.54 8.59
2.15
13.413.613.814.414.614.014.214.413.813.414.014.414.214.614.413.6
ON
xlO 2
xlO~ 3 xlO 3 xlO~ 2
xlO2
THE TELEVISION SCREEN
-A86-
TABLE D.I5 ELECTROPHORESIS OF COLLIERY WASTE-WATER AT pH = 5.3
CONDUCTIVITY (A) = 1.55 10 ohm x mCROSS-SECTIONAL AREA OF THE , n , n ~4 2 ELEC TROPHORETIC CELL (A) ~ mDISTANCE TRAVELLED BY THE ~ PARTICLES ON THE TELEVISION = 28.0 10 m SCREEN (X)
CIRCUIT REVERSED
MIGRATION TOWARDS THE POSITIVE ELECTRODE
d(m)V(volt) I ( amp ) R(ohm) Km)E(volt m- 1 )
3.7018.46
3.335.54 8.59
2.15
14.415.215.415.614.614.214.414.814.215.414.615.215.614.814.614.4
TIME (
3.7518.51 3.34 5.54 8.59
2.15
13.613.814.213.414.014.413.413.613.814.014.413.614.214.413.413.8
3.8018.54 3.34 5.55 8.60
2.15
12.813.213.413.613.012.412.613.213.413.612.813.012.612.412.812.6
3.8518.5 3.35 5.54 8.58
2.16
12.011 .811.211 .011.411 .811 .211 .611 .011 .011.611 .811.611 .211.412.0
SEC) TAKEN TO TRAVEL THETHE TELEVISION SCREEN
3.9018.53 3.34 5.54 8.61
2.15
12.012.413.012.612.812.212.612.413.012.612.812.412.212.612.412.6
DISTANCE
3.95 xlO 218.55 3.35 xlO~ 3 5.54 xlO 3 8.58 xlO~ 2
2.16 xlO2
13.213.414.213.613.814.214.013.613.813.213.613.613.414.013.613.4
ON
-A87-
TABLE D.I6 ELECTROPHORESIS OF COLLIERY WASTE-WATER AT pH = 5.3
CONDUCTIVITY (\ ) = 1.55 10 ohm mCROSS-SECTIONAL AREA OF THE , o 1 n~4 2 ELECTROPHORETIC CELL (A)DISTANCE TRAVELLED BY - PARTICLES ON THE TELEVISION = 28.0 10 m SCREEN (X)
CIRCUIT REVERSED
MIGRATION TOWARDS THE NEGATIVE ELECTRODE
d(m)V(volt) I ( amp ) R(ohm) Km)E(volt m-1)
4.0518.52 3.34 5.54 8.59
2.15
14.214.815.415.215.414.615.015.014.615.214.814.414.214.414.014.0
TIME (
4.1018.54 3.34 5.55 8.60
2.15
13.413.613.814.213.414.013.614.413.814.013.414,213.613.414.014.2
4.1518.49 3.34 5.54 8.59
2.15
12.812.612 .012.213.013.012.412.812.412.212.612.812.212.612.012.4
4.2018.52 3.34 5.54 8.59
2.15
12.011 .211 .211.411.812.011 .611 .811.211.811 .412.012.011 .011 .011.2
SEC) TAKEN TO TRAVEL THETHE TELEVISION SCREEN
4.2518.51 3.34 5.54 8.59
2.15
12.412.813.213.012.612.413.412.812.613.212.812.412.813.413.012.6
DISTANCE
4.30 xlO 218.54 3.34 xlO~ 3 5.55 xlO3 8.60 xlO~ 2
2.15 xlO 2
13.613.813.214.214.013.414.414.614.413.613.413.214.614.213.814.0
ON
-A88-
TABLE D.I 7 ELECTRO PHORESIS OF COLLIERY WASTE -WATER AT pH = 5.0
CONDUCTIVITY (X) = 1.56 10 ohm mCROSS-SECTIONAL AREA OF THE , _ _-4 2 ELECTROPHORETIC CELL (A) ~ U mDISTANCE TRAVELLED BY THE ~ PARTICLES ON THE TELEVISION = 28.0 10 m SCREEN (X)
MIGRATION TOWARDS THE NEGATIVE ELECTRODE
d(m)V(volt)I ( amp )R(ohm)Km)E(volt m-1)
3.7018.103.295.508.58
2.11
14.615.014.813.814.013.613.813.813.614.014.415.014.614.414.214.0
TIME (
3.7518.083.285.518.60
2.10
13.413.212.812.613.013.012.613.612.812.813.413.012.613.213.212.8
3.8018.093.285.528.60
2.10
12.212.412.612.212.013.013.212.812.012.612.813.012.212.412.013.2
3.8518.123.295.518.59
2.11
11.211 .011.611.211 .811.412.011 .811 .411 .211 .011 .811 .612.011.211.4
SEC) TAKEN TO TRAVEL THETHE TELEVISION SCREEN
3.9018.063.285.518.59
2.10
12.412.613.413.013.213.012.813.612.812.413.213.413.612.613.612.8
DISTANCE
3.95 xlO 218.073.28 xlO~ 35.51 xlO 38.59 xlO~ 2
2.10 xlO2
14.213.613.813.414.013.614.414.614.413.814.013.613.413.814.614.2
ON
-A89-
TABLE D.I 8 ELECTROPHORESIS OF COLLIERY WASTE-WATER AT pH = 5.0
CONDUCTIVITY (X) = 1.56 10 ohmCROSS-SECTIONAL AREA OF THE , n -, n~4 2 ELECTROPHORETIC CELL (A) 1 .u iu mDISTANCE TRAVELLED BY THE „ PARTICLES ON THE TELEVISION = 28.0 10 m SCREEN (X)
MIGRATION TOWARDS THE POSITIVE ELECTRODE
d(m)V(volt) I ( amp ) R(ohm) Km)E(volt m-1)
4.0518.11 3.29 5.50 8.59
2.11
14.013.814.6
15.014.8
14.414.2
14.614.4
15.014.8
14.214.6
14.613.8
14.4
TIME (
4.1018.13 3.29 5.51 8.60
2.11
13.813.613.4
13.013.8
13.613.2
13.413.4
13.213.0
13.813.6
13.413.8
13.2
SEC ) TAKEN
4.1518.14 3.29 5.51 8.60
2.11
12.212.012.412.613.213.012.812.612.613.012.212.212.813.212.012.4
4.2018.12 3.29
5.51 8.59
2.11
11 .4
11 .611 .2
12 .011 .6
11 .811 .0
11.211 .011 .211 .8
11 .411.412.0
11 .611 .2
TO TRAVEL THE
4.2518.11 3.29
5.50 8.59
2.11
12.413.012.6
12.813.2
13.412.8
13.413.4
12.612.4
13.212.6
12.412.8
12.8
DISTANCE
4.30 xlO 218.15 3.29 xlO~ 3 5.52 xlO 3 8.61 xlO~ 2
2.11 xlO2
14.014.213.6
13.814.2
14.214.0
14.414.6
14.414.6
13.814.8
13.613.8
14.8
ONTHE TELEVISION SCREEN
m
-A90-
TABLE D.I 9 ELECTROPHORESIS OF THE COLLIERY WASTE-WATER AT pH = 5.0
CONDUCTIVITY (X) = 1.56 10 ohm x mCROSS-SECTIONAL AREA OF THE , -4 2 ELECTROPHORETIC CELL (A) U U mDISTANCE TRAVELLED BY THE PARTICLES ON THE TELEVISION = 28.0 10 m SCREEN (X)
CIRCUIT REVERSED
MIGRATION TOWARDS THE NEGATIVE ELECTRODE
d(m)V(volt)I ( amp )R(ohm)Km)E(volt m-1)
3.7018.133.295.518.60
2.11
13.814.214.414.614.014.814.614.214.413.813.814.214.814.414.014.4
TIME (
3.7518.143.295.518.60
2.11
13.613.213.013.013.413.814.013.813.413.613.213.013.214.014.013.4
SEC ) TAKEN
3.8018.123.295.518.59
2.11
12.812.413.012.212.412.613.213.212.412.212.212.612.812.813.012.4
3.8518.153.295.528.61
2.11
11 .811 .612.011 .411 .611.411.211 .411 .211 .811 .412.012.011.211 .811.2
TO TRAVEL THE
3.9018.083.285.518.60
2.10
12.612.412.213.413.612.813.013.213.412.813.012.613.212.413.612.2
DISTANCE
3.95 xlO 218.123.29 xlO~ 35.51 xlO 38.59 xlO~ 2
2.11 xlO 2
13.413.014.213.813.613.614.014.413.813.414.014.414.213.014.413.8
ONTHE TELEVISION SCREEN.
-A91-
TABLE D.20 ELECTROPHORESIS OF COLLIERY WASTE-WATER AT pH = 5.0
CONDUCTIVITY (A)CROSS-SECTIONAL AREA OF THE ELECTROPHORETIC CELL (A)DISTANCE TRAVELLED BY THE PARTICLES ON THE TELEVISION SCREEN (X)
CIRCUIT REVERSED
= 1.56 10 ohm m=1.0 10~4 m2
= 28.0 10~2 m
MIGRATION
d(m)V(volt) I ( amp ) R(ohm) l(m)E(volt m-1)
4.0518.16 3.30 5.50 8.58
2.12
14.414.814.214.414.615.015.214.815.014.614.214.614.415.214.614.2
TIME (
4.1018.20 3.30 5.52 8.60
2.12
13.214.013.814.213.613.413.813.213.814.213.413.614.213.214.013.6
SEC) TO
TOWARDS THE POSITIVE ELECTRODE
4.1518.22 3.30 5.52 8.61
2.12
12.412.612.813.213.012.012.212.612.212.812.013.012.413.212.612.4
TRAVEL THE
4.2018.25 3.30 5.53 8.63
2 .12
12 .212.412.011 .811 .612.411.411.212.411 .812.212.411.611.211.811.4
4.2518.21 3.30 5.52 8.61
2.12
12.613.012 .012.812.212.613.012.412.212.012.612.412.812.012.612.4
4.30 xlO 218.23 3.30 xlO~ 3 5.52 xlO 3 8.62 xlO~ 2
2.12 xlO 2
13.614.214.014.413.813.413.614.013.814.413.414.013.614.213.814.4
DISTANCE ON THETELEVISION SCREEN
-A92-
TABLE D.21 ELECTROPHORESIS OF COLLIERY WASTE-WATER AT pH = 4.0
CONDUCTIVITY (X)
CROSS-SECTIONAL AREA OF THE ELECTROPHORETIC CELL (A)
DISTANCE TRAVELLED BY THE PARTICLES ON THE TELEVISION SCREEN (X)
= 1 .62 10 ohm
= 1.0 10~ 4 m2
28.0 10~ 2 m
m
MIGRATION TOWARDS THE NEGATIVE ELECTRODE
d(m)V(volt) I ( amp ) R(ohm) Km)E(volt m-1)
3.7017.72
3.33 5.32 8.62
2.06
14.414.213.813.613.614.014.614.814.014.414.614.214.813.614.214.0
TIME (
3.7517.74 3.33 5.33 8.63
2.06
13.213.413.613.013.013.813.213.813.413.013.213.613.413.413.613.8
3.8017.73
3.33 5.32 8.63
2.06
12.812.612.612 .012.412.213.013.212.412.813.212.412.013.012.212.6
3.8517.76 3.34 5.32
8.61
2.06
12.011 .811.211 .611.811 .211 .011.411 .611.011 .012.011.611.811.411.2
SEC) TAKEN TO TRAVEL THE
THE TELEVISION SCREEN
3.9017.75 3.33 5.33 8.64
2.06
12.413.012.812.613.013.613.412.412.613.613.213.413.212.812.413.0
DISTANCE
3.95 xlO 217.71 3.33 xlO~ 3 5.32 xlO 3
8.62 xlO~ 2
2.06 xlO2
13.413.814.014.214.614.213.814.414.013.614.214.414.614.013.613.8
ON
-A93-
TABLE D.22 ELECTROPHORESIS OF COLLIERY WASTE-WATER AT pH = 4.0
CONDUCTIVITY (X) = 1.62 10 l ohm l m lCROSS-SECTIONAL AREA OF THE , n , »-4 2 ELECTROPHORETIC CELL (A) - J-.U ±U mDISTANCE TRAVELLED BY THE ? PARTICLES ON THE TELEVISION = 28.0 10 m SCREEN (X)
MIGRATION TOWARDS THE POSITIVE ELECTRODE
d(m)
V(volt) I ( amp ) R(ohm) Km)E(volt m- 1 )
4.0517.71
3.33 5.32 8.62
2.06
13.814.214.613.814.815.015.215.014.414.814.214.414.613.814.014.0
TIME (
4.1017.74
3.33 5.33 8.63
2.06
13.814.013.413.613.212.814.214.414.614.214.013.613.813.413.013.0
4.1517.69 3.335.31 8.61
2.06
13.212 .612.812.412.213.012.412.613.012.412.612.813.212.212.412.2
4.2017.70 3.33 5.32 8.61
2.06
11 .811 .611 .411 .211 .012.212.011.811 .611.011.211.812.011.411.011.2
SEC) TAKEN TO TRAVEL THETHE TELEVISION SCREEN
4.2517.68 3.32 5.33 8.63
2.05
12.212.612 .812.213.012.812.413.212.012.412 .613.212.013.012.612.2
DISTANCE
4.30 xlO 217.71 3.33 xlO~ 3 5.32 xlO 3 8.62 xlO~ 2
2.06 xlO 2
13.413.812.813.012.813.613.814.214.414.214.013.614.414.614.014.6
ON
-A94-
TABLE D.23 ELECTROPHORESIS OF COLLIERY WASTE-WATER AT pH = 4.0
CONDUCTIVITY (X)
CROSS-SECTIONAL AREA OF THE ELECTROPHORETIC CELL (A)
DISTANCE TRAVELLED BY THE PARTICLES ON THE TELEVISION SCREEN (X)
CIRCUIT REVERSED
= 1 .62 10 ohm -A ?
= 1 .0 10 m
= 28.0 10~2 m
m
MIGRATION TOWARDS THE NEGATIVE ELECTRODE
d(m)V(volt) I ( amp ) R(cxhm) Km)E(volt m" 1 )
3.7017.66
3.32 5.32 8.62
2.05
15.014.813.613.814.014.414.614.213.814.414.214.814.2
15.013.614.6
TIME (
3.7517.67
3.32 5.32 8.62
2.05
13.814.013.2
13.013.613.813.414.013.613.213.414.013.813.413.013.2
3.8017.74 3.33 5.33 8.63
2.06
12.612.812.413.013.212.012.212.613.012 .612.213.212.412.012.812.4
3.8517.76 3.34 5.32 8.61
2 .06
11 .4
11 .011 .011 .411 .211.811.612.011 .611 .411.211 .211 .812.011.811 .2
SEC) TAKEN TO TRAVEL THE
THE TELEVISION SCREEN
3.9017.71 3.33 5.32 8.62
2.06
12.813.413.212.613.613.013.812 .613.013.212.812.812.613.413.413.0
DISTANCE
3.9517.69 3.33 5.31 8.61
2.06
13.414.014.213.813.614.414.614.414.813.813.414.014.613.614.214.8
ON
xlO~ 2
xlO~ 3 xlO 3 x!0" 2
xlO2
-A95-
TABLE D.24 ELECTROPHORESIS OF COLLIERY WASTE-WATER AT pH = 4.0
CONDUCTIVITY (X) = 1.62 10 ohm m
CROSS- SECTIONAL AREA OF THE , n , n~4 2 ELECTROPHORETIC CELL (A) ~ U m
DISTANCE TRAVELLED BY THE PARTICLES ON THE TELEVISION = 28.0 10 m SCREEN (X)
CIRCUIT REVERSED
MIGRATION TOWARDS THE POSITIVE ELECTRODE
d(m)V(volt)I ( amp )R(ohm)Km)E(volt m-1)
4.0517.743.335.338.63
2.06
14.613.814.214.014.414.814.814.613.814.013.814.414.214.014.214.4
TIME (
4.1017.73
3.335.328.63
2.06
13.213.013.413.013.613.814.013.813.013.813.613.213.413.413.013.2
4.1517.673.325.328.62
2.05
12.812.612.012.212.612.412.812.013.013.012.812.412.212.212.012.4
4.2017.68
3.325.338.63
2.05
11.611.211 .411.811 .811 .011 .011.412.0
11 .611.211.411.011.411 .612.0
SEC) TAKEN TO TRAVEL THE
THE TELEVISION SCREEN
4.2517.693.335.318.61
2.06
12 .612.413.2
13.012.813.013.213.412.812.412.613.413.0
12.612.612.4
DISTANCE
4.30 xlO 217.743.33 xlO~ 3
5.33 xlO 38.63 xlO~ 2
2.06 xlO2
14.213.813.614.014.414.414.814.614.013.613.413.413.814.214.614.8
ON
-A96-
TABLE D.25 ELECTROPHORESIS OF COLLIERY WASTE -WATER AT pH = 3.0
CONDUCTIVITY (X) = 2.00 10 ohm m
CROSS-SECTIONAL AREA OF THE , n , n ~4 2 ELECTROPHORETIC CELL (A) - J..U J-U m
DISTANCE TRAVELLED BY THE 0 PARTICLES ON THE TELEVISION = 28.0 10 m SCREEN (X)
MIGRATION TOWARDS THE NEGATIVE ELECTRODE
d(m)V(volt) I ( amp ) R(ohm) Km)E(volt
3.7017.30 4.02 4.30 8.61
2.01
13.613.814.014.2
13.414.013.214.213.413.013.013.213.813.613.413.6
TIME (
3.7517.32 4.03 4.30 8.60
2.02
12.812.613.413.013.213.012.612 .813.613.4
13.012.6
13.012.813.213.2
SEC) TAKEN
3.8017.29 4.02 4.30 8.60
2.01
12.812.212.412.2
12 .012.613.012.612.212.012.412 .412.2
13.012.812.4
3.8517.30 4.02 4.30 8.61
2.01
12.211 .811 .611 .212.011.811.011 .411 .011.2
11 .812.212.011 .611.211.4
TO TRAVEL THE
3.9017.31 4.02 4.31 8.61
2.01
12.412.813.213.612.012.612.812.012.212.612.812 .012.412.212.212.8
DISTANCE
3.9517.35 4.03 4.31 8.61
2.02
12 .812.4
13.013.412.612.8
13.213.013.412.612.813.213.013.012.412.6
ON
xlO 2
xlO~ 3 xlO 3 xlO~ 2
xlO2
THE TELEVISION SCREEN
-A97-
TABLE D.26 ELECTROPHORESIS OF COLLIERY WASTE-WATER AT pH = 3.0
CONDUCTIVITY (X)CROSS-SECTIONAL AREA OF THE ELECTROPHORETIC CELL (A)DISTANCE TRAVELLED BY THE PARTICLES ON THE TELEVISION SCREEN (X)
= 2.0 10 ohm-A. 7= 1.0 10 rn
= 28.0 10"" 2 m
m
MIGRATION TOWARDS THE POSITIVE ELECTRODE
d(m)
V(volt) I ( amp ) R(ohm) Km)E(volt m-1)
4.05
17.36
4.03
4.31
8.62
2.02
14.4
14.0
13.8
13.6
13.0
14.2
14.0
13.4
13.6
14.2
14.0
13.8
13.4
13.2
14.4
14.2
TIME (
4.1017.33 4.03 4.30 8.60
2.02
12.813.012.612.412.813.213.412.613.413.613.8
13.012.413.413.013.6
4.15
17.32
4.03
4.30
8.60
2.02
12.6
12.8
12.2
12.8
12 .2
12 .4
12.6
13.0
12.4
13.0
12.2
12.4
12.8
12.6
12 .4
13.0
4.20
17.35
4.03
4.31
8.61
2.02
11 .4
11.2
11 .0
12.0
11.8
11 .4
11 .2
11.6
11 .6
11 .8
11 .2
11 .2
12.0
11 .0
11 .4
11.4
SEC) TAKEN TO TRAVEL THE
THE TELEVISION SCREEN
4.25
17.34
4.03
4.30
8.61
2.02
12.8
13.0
13.4
12 .6
12.4
12.8
13.2
13.0
12.6
13.0
13.2
12.4
12.8
13.4
12.8
12.4
DISTANCE
4.30 xlO~ 2
17.37
4.03 xlO~ 3
4.31 xlO3
8.62 xlO~ 2
2.02 xlO2
13.4
13.6
14.0
14.4
14.6
14.2
13.8
14.0
14.2
13.6
14.4
13.4
13.8
14.6
13.6
13.4
ON
-A98-
TABLE D.27 ELECTROPHORESIS OF COLLIERY WASTE-WATER AT pH = 3.0
CONDUCTIVITY (X)CROSS-SECTIONAL AREA OF THE ELECTROPHORETIC CELL (A)DISTANCE TRAVELLED BY THE PARTICLES ON THE TELEVISION SCREEN (X)
CIRCUIT REVERSED
= 2.0 10 ohm=1.0 10~4 m2
= 28.0 10 2 m
m
MIGRATION TOWARDS THE NEGATIVE ELECTRODE
d(m)V(volt)I ( amp )R(ohm)Km)E(volt
m~l )
3.7017.344.034.308.61
2.02
14.013.814.414.014.213.613.414.214.413.613.814.213.613.413.814.0
TIME (
3.7517.364.034.318.62
2.02
12.613.413.213.013.412.812.413.613.612.812.613.013.013.613.213.2
3.8017.334.034.308.60
2.02
12.412.812.213.013.212.012.412.612.212.613.012.812.212.412.012.4
3.8517.314.024.318.61
2.01
11.211 .811.411.611 .012 .011 .612.011.411 .211.011.011 .811.612.011.0
SEC) TAKEN TO TRAVEL THETHE TELEVISION SCREEN
3.9017.324.034.308.60
2.02
12.412.212 .813.012 .612.412.012.813.012.612.012.012.412.213.012.6
DISTANCE
3.95 xlO 217.364.03 xlO~ 34.31 xlO 38.62 xlO~ 2
2.02 xlO2
13.013.413.813.614.214.013.213.413.814.213.614.013.413.213.013.2
ON
-A99-
TABLE D.28 ELECTROPHORESIS OF COLLIERY WASTE-WATER AT pH = 3.0
CONDUCTIVITY (X) =2.0 10 ohm" 1 m" 1CROSS-SECTIONAL AREA OF THE , _-4 2 ELECTROPHORETIC CELL (A) -1.U1U mDISTANCE TRAVELLED BY THEPARTICLES ON THE TELEVISION = 28.0 10 mSCREEN (X)
CIRCUIT REVERSED
MIGRATION TOWARDS THE POSITIVE ELECTRODE
d(m)V(volt)I ( amp )R(ohm)Km)E(volt m- 1 )
4.0517.324.034.308.60
2.02
14.214.013.813.814.413.614.014.614.213.613.813.614.014.214.614.4
TIME (
4.1017.354.024.318.61
2.02
13.213.013.813.813.012.813.413.613.013.613.213.413.413.013.613.2
4.1517.304.024.308.61
2.01
12.812.612.412.013.013.212.812.213.012.412.212.013.212.812.612.4
4.2017.284.024.308.60
2.01
11 .411.211.811 .011.612.012.211.412.211.611 .811.211 .011.011.211.4
SEC) TAKEN TO TRAVEL THETHE TELEVISION SCREEN
4.2517.344.034.308.61
2 .02
12.412.813.012.612.413.213.413.012.612.412.813.412 .613.013.212.6
DISTANCE
4.30 xlO 217.354.03 xlO~ 34.31 xlO38.61 xlO~ 2
2.02 xlO2
13.413.213.814.214.014.413.614.013.813.414.013.614.414.213.813.2
ON
-A100-
DEFINITIONS
Electrophoresis is the movement of a charged surface material relative to stationary liquid by an applied electric
field.
Electro-osmosis is the movement of liquid relative to
a stationary charged surface by an applied electric field.
Streaming potential is the electric field which is
created when liquid is made to flow along a stationary charged
surface.
Sedimentation potential is the electric field which is
created when charged particles move relative to the stationary
liquid.
VARIATION OF pH WITH CONDUCTIVITY - 2000cc OF COLLIERY WASTEWATER IN 0.4MHC£
HCJl
0.0
i:0
2.0
3.0
5.0
6.0
7.0
8.0
10.0
15.0
20.0
30.0
41.0
pH
8.60
8.45
8.30
8.15
7.80
7.60
7.60
7.55
7.42
7.15
7.00
6.75
6.50
Conductiv ity (ohm m )
1.360 10" 1
1.365 10"1
1.370 10"1
1.375 10"1
1.380 10"1
1.390 10"1
1.390 10"1
1.40 10"1
1.41 10"1
1.43 10" 1
1.44 10" 1
1.46 10" 1
1.48 10" 1
KCSi
50.0
60.0
65.0
70.0
75.0
80.0
82.0
83.0
83.5
84.0
85.0
86.0
87.0
pH
6.33
6.10
6.00
5.85
5.65
5.30
5.10
4.98
4.85
4.80
4.45
4.05
3.80
Conductivit (ohm m
1.50 10"1
1.55 10"1
1.58 10"1
1.59 10"1
1.60 10'1
1.61 10"1
1.61 10~l
1.61 10"1
1.61 10"1
1.62 10" 1
1.64 10"1
1.68 10~l
1.70 10" 1
!y HC£
88.0
90.0
95.0
100.0
110.0
130.0
150.0
175.0
200.0
250.0
300.0
350.0
400.0
pH
3.65
3.40
3.10
2.90
2.70
2.50
2.35
2.20
2.10
1.95
1.85
1.80
1.70
Conductivity (ohm m
1.75 10"1
1.81 10" 1
2.00 10"1
2.20 10"1
2.58 10'1
3.20 10" 1
4.08 10" 1
4.96 10" 1
5.80 10" 1
7.40 10" 1
8.00 10" 1
10.80 10" 1
11.80 KT1
VARIATION OF pH WITH CONDUCTIVITY - lOOOcc.OF COLLIERY WASTEWATER 0.4M.H
H 2 S04
0.000.50
1.00
1.50
2.00
3.00
4.00
5.00
6.00
7.00
8.00
9.00
10.00
pH
8.80
8.35
7.70
7.50
7.30
7.05
6.80
6.65
6.50
6.40
6.25
6.10
5.95
Conductivity (ohm~ m -1 )
1.34 10" 1
1.35 lO'1
1.36 10" 1
1.37 lO'1
1.38 10" 1
1.39 10"1
1.41 10" 1
1.42 10"1
1.44 10"1
1.45 10"1
1.47 10"1
1.49 10"1
1.50 10"1
H 2 S04
(cc)
11.0
11.50
12.00
12.20
12.50
12.60
12.70
12.80
13.00
13.20
13.50
14.00
15.00
pH
5.70
5.60
5.30
5.25
5.00
4.80
4.70
4.45
4.00
3.75
3.50
3.30
3.00
Conductivity ( ohm m )
1.52 10' 1
1.54 10" 1
1.55 10" 1
1.55 10" 1
1.56 lO'11.56 10"" 1
1.58 10" 1
1.59 10" 1
1.62 10" 1
1.65 10" 1
1.72 10" 1
1.80 10'1
2.00 10" 1
? H 2 SO^
16.00
18.00
20.10
25.00
30.00
40.00
50.00
60.10
80.00
.00.00
pH
2.85
2.70
2.55
2.35
2.20
2.00
1.90
1.80
1.70
1.60
Conductivity
2.22 10" 1
2.62 10"1
3.02 W~l
3.90 10" 1
4.90 10" 1
6.60 10" 18.40 lO"-1
10.00 10" 1
13.00 10" 1
16.20 10" 1
VARIATION OF pH WITH CONDUCTIVITY- lOOOcc OF lOOp.p.m IN QUARTZ IN 0.4M.HCJI
HC£ (cc)
0.00
0.10
0.20
0.30
0.40
0.50
0.70
1.00
1.20
1.50
2.00
3.00
5.00
PH
5.18
4.90
4.74
4.55
4.40
4.30
4.20
4.05
3.95
3.85
3.80
3.65
3.50
Conductivity (ohmT-*- m-1
3.92 10~4
6.60 10~ 4
9.00 10~4
14.10 10~4
19.80 10~4
25.20 10~4
34.0 10~4
48.0 10~4
60.00 10~4
75.00 10~4
94.0 10~4
145.0 10~4
240.0 10~4
HC£ (cc)
7.00
10.00
15.00
25.00
35.00
50.00
70.00
100.00
150.00
200.00
250.00
PH
3.30
3.16
3.00
2.85
2.75
2.60
2.40
2.30
2.10
2.05
1.95
Conductivity (ohm" 1 m"1
338. 10~4
488. 10~4
730. 10~4
1.21 10'1
1.72 10" 1
2.40 10"1
3.30 10"1
4.70 10"1
6.70 10"1
8.50 10"1
10.40 10"1
VARIATION OF pH WITH CONDUCTIVITY- lOOOcc OF lOOp.p.m. IN QUARTZ in 0.4M H-SO
H 2 S04
(cc)
0.00 j
0.10
0.25
0.40
0.50
1.00
2.00
3.00
5.00
7.00
10.00
15.00
20.00
pH
5.18
4.30
3.95
3.75
3.65
3.40
3.10
3.00
2.80
2.65
2.55
2.40
2.30
Conductivity/ x. "I -^ (ohm m )
3.70 10~4
27.80 10~ 4
62.00 10~ 4
110.0 10~ 4
145.0 10~4
265.0 10~4
520. 10~4
770. 10~ 4
1.22 10"1
1.70 10" 1
2.30 10"1
3.28 10"1
4.18 10"1
H 2 S04
(cc)
30.00
50.00
75.00
100.00
150.00
200.00
250.00
pH
2.15
2.00
1.85
1.80
1.70
1.60
1.50
Conductivity, , -1 -1. (ohm m )
6.0 10" 1
9.25 10"1
12.90 10"1
16.50 10" 1
22.80 10""1
28.0 10" 1
32.80 KT1