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Masters Theses Student Theses and Dissertations

1967

Studies in coprecipitation of trace amounts of elements Studies in coprecipitation of trace amounts of elements

Gerald Delano Schucker

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STUDIES IN COPRECIPITATION OF TRACE AMOUNTS OF ELEMENTS

BY

GERALD DELANO SCHUCKER - I e,.,

A

THESIS

submitted to the faculty of

THE UNIVERSITY OF MISSOURI AT ROLLA

in partial fulfillment of the requirement for the

Degree of

MASTER OF SCIENCE IN CHEMISTRY

Rolla, Missouri

1967

Approved by

(advisor)

ABSTRACT

A new approach to preconcentration of trace amounts of elements

has been demonstrated whereby traces of metals tied up as chelates

are coprecipitated on a column of solid organic material. Complete

coprecipitation was found to occur within very narrow pH ranges,

thereby allowing separation as well as concentration of the elements

by careful adjustment of acidity and concentration of chelating

agent. The separation is based on the difference in stability

constants of the metal chelates. Preliminary studies with different

physical forms of the carrier precipitate, indicate adsorptive

processes could play a significant role in the mechanism of the

column-coprecipitation process.

The applicability of Atomic Absorption Spectrophotometry for

the determination of traces of metals in coprecipitation studies

has been investigated. Sensitivity limits for nine elements have

been established and the effect of certain organic reagents on

their standard curves determined. A new quantitative indirect

method for the determination of trace amounts of chelating agent

.has been descri~ed.

TABLE OF CONTENTS

LIST OF FIGURES LIST OF TABLES

• Ill ................... ,.. •••••••• «> •

.............................. I.

II.

III.

IV.

v.

INTRODUCTION e • • e o • • • • • • o • • • e • * • • • • • • • • o • • • o • • • • • • • •

REVIEW OF LITERATURE ............................... QUANTITATIVE MEASUREMENT OF TRACE COMPONENTS ••••••••

A.

B.

Determination of Trace Amounts of Metals . ........ . 1. Experimental

a. Reagents . b. Apparatus c. Standards

............................... ............................... ............................. 4 • • ...............................

2. Results and Discussion • •••••••••••• Ill'"' ••••••

a. Detection Limits ..................... "" .... b. Effect of Organic

Indirect Determination of . ............ . Materials

Trace Amounts

1. 2 ..

of Chelating Agents ........................... Experimental . ......................... . Results and Discussion . ..................... ""'.

COLUMN-COPRECIPITATION STUDIES • ................. •· •• ill ..

A.

B.

General Experimental Procedure for Coprecipitation ••••••••••••••••••••••••••••••

Results and Discussion •••••••••••••••••••••••·• 1. 2.

Oxine-Phenolphthalein System . ............. ., .. Oxine-2-Naphthol System ................. it ••••

CONCLUSIONS ......................................... BIBLIOGRAPHY ............. ,. ............ "' .... ,. ...... . APPENDIX ................................. ., ...... "" ... . ACKNOWLEDGMENTS ...................................... VITA ..................................................

1

4

9

9 9

20

39

iv

LIST OF FIGURES

Figure Page

1. Effect of Organic Materials on Standard Curve

for Zinc ••••••••••••••••••••••••••••••••••••••••••• 13

2. Attenuation of Copper Absorption Signal by Oxine •••

3. Effect of pH on Percentage Coprecipitation of

Copper Oxinate at a 1000 Fold Oxine and Phenol-

17

phthalein as Carrier ••••••••••••••••••••••••••••••• 22

4. Effect of pH on Coprecipitation Recovery and Sep-

aration of Four Metals with Oxine and 2-Naphthol •• , 30

5. Percentage Coprecipitation of Cadmium Oxinate as a

Function of Amount of Excess of Complexing Agent .. ' 33

6. The Coprecipitation Recovery of Silver with Oxine

and 2-Naphthol ••••••••••••••••••••••••••••••••••••• 37

?.

8.

9.

10.

11.

).2.

13.

14.

15.

16.

Standard Curve for Manganese •••••••••••••••••••••••

Standard Curve for Cobalt ••••••••••••••••••••••••••

Standard Curve for Cadmium .. ........................ Standard Curve for Cadmium . ........................ Standard Curve for Nickel .......................... Standard Curve for Silver .......................... Standard Curve for Lead ............................ Standard Curve for Zinc ............................ Standard Curve for Copper . ......................... Standard Curve for Gold ............................

46

47

48

49

50

51

52

53

54

55

LIST OF TABLES

Tabl.e

I. Retention of Trace Amounts of Copper Oxinate by

Phenolphthalein using 1000 fold Excess Oxine ••••••••

II. Effect of Carrier Weight on the Coprecipitation of

Copper Oxinate using phenolphthalein and a 1000 fold

Excess Oxine •••••••••••••••••••••••••••••••••••••••

III. A Comparison of the Coprecipitation Ability of Solid

Phenolphthalein to that Re-precipitated from an

Alcoholic Solution •••••••••••••••••••••••••·•••••••

IV. Retention of Trace Amounts of Copper Oxinate by

2-Naphthol using 1000 fold Excess Oxine ••••••••••••

V. Retention of Trace Amounts of Cobalt Oxinate by

2-Naphthol using 1000 fold Excess Oxine •·••••••••••

VI. Retention of Trace Amounts of Cadmium Ox:inate by

2-Naphthol using 1000 fold Excess Oxine ............. VII. Retention of Trace Amounts of Manganese Oxinate by

2-Naphthol using 1000 fold Excess Oxine ............... VIII. Correlation of Chelate Stability Constants with

Experimental pH~ Values ••••••••••••••••••••••••••••

IX. The Relative Percent Absorption of Standard

Solutions of Gold as a Function of pH ••••••••••••••

X. Instrument Parameters ••••••••••••••••••••••••••••••

v

1

I. INTRODUCTION

The importance of trace amounts of inorganic ions in chemical,

physical, and biological systems has come to the forefront in the

past decade. Analytical chemists have been called upon to analyze

for many elements at the part per million and even part per billion

levels. Satisfactory methods are usually available for the deter­

mination of microgram amounts of most ions, but in many instances

separation and concentration of the trace elements from large

amounts of the matrix or major constituent is often a necessary

preliminary step in their quantitative determination. Chemical

enrichment procedures often employed include: chromatography, ion­

exchange, solvent extraction, and precipitation with organic re­

agents. The phenomenon of coprecipitation using either inorganic

or organic coprecipitating agents has rec.eived extensive study as

a preconcentration technique.

When the quantity of an element in solution is less than that

required to exceed the solubility product, direct precipitation is

impossible. However it has been shown previously by several

workers that small quantities of metal ions tied up as chelates

can be extracted (coprecipitated) from aqueous solution by solid

organic carrier precipitates (4,23,30). The use of these organic

coprecipitants permits one to extend the limits of application of

organic precipitation to solutions of lower concentration of the

elements to be precipitated. For example, at a dilution of 1:107

2

nickel is not precipitated by 8-hydroxyquinoline (oxine). However

when 2-naphthol is used as a coprecipitant, complete coprecipitation

of the nickel oxinate takes place.

In previous coprecipitation work, the usual method of adding

the carrier precipitate to the aqueous solution of trace metal and

chelating agent has been from a solution of the carrier in an organic

solvent. This study is devoted to an investigation of a new method

of using the carrier precipitate.

There is strong reason to believe that freshly precipitated

fine-grained organic precipitates could be made the basis of a

column technique whereby metal ions tied up as chelates could be

extracted (coprecipitated) on the column in the presence of an

excess of the chelating agent. It is then possible that a selective

separation of the metals can be made by elution with various pH

buffered solutions and/or various concentrations of the chelating

agent.

Therefore the purpose of this study was to determine the

feasibility of a new approach to preconcentration of trace elements,

column-coprecipitation, by investigating the retention and elution

of trace element complexes on columns of organic coprecipitants.

Also to be investigated was the applicability of Atomic

Absorption Spectrophotometry for the quantitative determination

of trace amounts of metals in coprecipitation studies.

The significance of this work stems from the need for better

methods to accurately measure ultramicro quantities of elements

which have recently been shown to be so important in such fields

as geochemistry, pure materials research, ie., semiconductors,

3

superconductors, nuclear reactor materials, etc., and in biological

systems.

4

II. REVIEW OF LITERATURE

One of the earliest workers to use the phenomenon of co-

precipitation for the concentration of trace amounts of elements

was Mitchell (23). Using 8-hydroxyquinoline as the complexing

agent with various other metal oxinates as carrier precipitates,

and later (24) in combination with tannic acid and thionalid, he

was successful in quantitatively precipitating many trace elements

of biological importance in plant materials and soil extracts.

Several modifications of this method appeared later (1-3,25-27,29).

In 1954 V.I. Kuznetsov began an extensive series of articles

entitled "Organic Coprecipitants" (4-20). He employed a variety

of techniques or mechanisms of the coprecipitation process in

developing practical analytical methods for the concentration of

trace elements, particularly from soils and natural waters. If

for example an element is capable of forming a complex anion, he

found a good carrier precipitate would be the salt of a large

organic cation having low solubility, high molecular weight, and

containing the same anion that was used for forming the complex

anion of the element. Bismuth in the form of an iodide complex

anion Bii4 , is quantitatively coprecipitated by a precipitate of

methyl violet even at dilutions of 1:108 • Conversly, if an element

forms a complex cation such as Me(o-phenanthroline); , the carrier

precipitat~ should be a heavy organic anion.

Kuznetsov also investigated the concentration of trace amounts

of metals, tied up as chelates, by the use of "indifferent copre-

cipitates", that is, organic molecules that are structurally

dissimiliar to the chelating molecule. He compared the use of

these indifferent coprecipitants to liquid extraction and termed

it "extraction by solid solvents". This comparison was later

studied in detail by Tappmeyer (30) in an attempt to obtain a

quantitative correlation of solid coprecipitation to liquid ex-

traction. Using various chelating systems and metal ions it was

shown that the factors influencing coprecipitation of the metal

chelates with indifferent coprecipitants were the same as those

that influence solvent extraction. Metal chelates that were ex-

tracted well with solvents like CC14 were also extensively

coprecipitated with organic coprecipitants. Excellent agreement

was found between experimental plots of percent coprecipitation

vs. pH and calculated plots using the same type of equilibrum

5

considerations used in solvent extraction. Results thus indicate

that factors which influence the extent of coprecipitation of

metal chelates with organic carriers can be combined into one

unified expression which is quantitatively identical to the ex-

pression used for the equilibria involved in extraction of metal

chelates by organic solvents:

-1

G H+J ~ H+j-l D = KfKd K~ . + k. K. .

x ~ R ~ ~ HR aq aq

where ki and Kf = first and total formation constants of the

given chelate

Ki = ionization constant of the chelating agent

n = charge on the metal

6

HR = concentration of chelating agent in the aq

aqueous phase

Kdx = distribution coefficient of the chelate

between the organic and aqueous phase

D = distribution ratio of the metal between

the two phases

Weiss and co-workers (21,32-36) have studied the co-

crystallization of trace quantities of elements from solution

by organic reagents, however their technique required only one

reagent and simplified the operating procedure by direct

crystallization of the reagent from solution. They claim the

coprecipitation process follows Fajans Rule which predicts that

the crystallized organic reagent will be enriched with the trace

element if the trace element and organic reagent combine to form

a compound whose insolubility is greater than that of the reagent

alone. Therefore the rule could be used as a basis for the

selection of organic compounds for cocrystallizing an element from

very dilute solution. The studies by Weiss indicate many diverse

elements could be cocrystallized with organic reagents. Analytical

methods were devised for the determination of many of these elements

in seawater.

In., the work by Weiss, the mechanism is probably different

from "indifferent coprecipitation" and doubtless involves ion-

exchange of the trace metal ion for one of the cations of the

organic reagent. This ion-exchange type mechanism is also

advanced by Troiskii (31) to explain the coprecipitation of trace

metals with inorganic compounds such as metal sulfides, hydroxides,

7

and for the isolation of radioactive elements by coprec

He found that full coprecipitation of the microcomponent does

indeed occur when the solubility product of the microcomponent is

smaller than that of the corresponding coprecipitant. This

has been confirmed for many elements with various coprecipitanta.

However there have been several exceptions noted where the

rule was inapplicable and coprecipi tation was neither coaplete no:r:

selective thus indicating the apparent adsorptive nature o! co­

precipitation.

Although most of the literature concerning coprec tat ion

reports on work directed toward the development of prac

analytical methods, a few studies concerning mechanisms of oo.­

precipitation of organic chelates on organic precipitates have

been carried out. Williams ( 37), working under condi tion.a that

the solubility of the metal chelate had definitely not been ex­

ceeded, proved that true coprecipitation does occur. Moreover

his studies revealed that the microcomponent is extracted by a

metastable liquid phase and then mechanically trapped by the

carrier during precipitation. Since the carrier precipitate was

found to release appreciable quantities of the trace element on

aging, occlusion appeared to be the principle mechanism.

It should be noted that the aboye transient liquid mec

is only applicable to experiments where the carrier preci tate

is added from an organic solvent and would not be a factor in the

present study where organic solvents were not used.

Williams further concluded that: (l) the efficiency of' co­

precipitation is directly proportional to the fraction of metal

8

complexed (E = KF) ; (2) the percentage coprecipitation is depend­

ent upon the method of precipitation of the carrier ; (3) adsorp­

tion of the microcomponent by the carrier contributes little to

the total amount coprecipitated.; (4) the amount of chelating

agent coprecipitated influences the amount of chelate coprecipitated.

The great amount of literature dealing with coprecipitation

by inorganic compounds, such as, metal hydroxides, sulfides,

calcium phosphate, germanium dioxide, tungstic acid, calcium

oxalate, etc., has not been surveyed in this work because of the

difference in mechanism. In these cases adsorption, ion-exchange,

and collodial phenomenon are doubtless the prominent factors. It

is difficult to see how the mechanism proposed for the coprecipitation

of lead ions by barium sulfate can apply for example to the co­

precipitation of traces of metal oxinates with phenolphthalein.

A survey of the literature did not reveal any attempt at the

separation and concentration of trace elements using a chelating

agent and a column of solid organic coprecipitant. The present

work was initiated to study this new approach.

III. QUANTITATIVE MEASUREMENT OF TRACE COMPONENTS

A. Determination of Trace Amounts of Metals

A necessary prerequisite in any investigation of preconcen­

tration techniques is an accurate analytical method for the

determination of ultramicro quantities of metals. Previous

workers studying coprecipitation have primairly used emission

spectroscopy, colorimetric methods, or radioisotopes. Each of

these techniques have several disadvantages. Emission spec­

troscopy although a good general survey tool, lacks precision

and accuracy. Colorimetric methods generally are applicable for

only one element at a time and often require time consuming wet

ashing procedures to destroy organic matter. Radioisotopes,

perhaps the most sensitive method for ultratrace work, require

special facilities for handling radioactive materials.

Within the past decade, a new instrumental technique, Atomic

Absorption Spectrophotometry, has been developed for trace metal

analysis. Part of the purpose of the present work was to in­

vestigate the usefulness of Atomic Absorption for coprecipitation

studies.

1. EKperimental

The sensitivity limitations of Atomic Absorption were

investigated for the elements of interest in coprecipitation

stadies by preparing calibration curves in the lowest concen­

tration ranges for which accurate absorption measurements could

be obtained. The influence of organic reagents upon these curves

was determined.

9

a. Reagents. All reagents used were of reagent grade and

were employed without further purification. Stock solutions

10

(1 mg./ml. of metal ion) of Cuso4 .5H2o , CoC12 .6H2o , CdC12 ,

MnC12 .4H2o 9 Ni(N03 ) 2 .6H20 , Pb(No3 ) 2 , Zn(N03 ) 2 .6H20 , and AgN03

were pre.pared by dissolving the salts in distilled water.

Suitable aliquots of each of the stock solutions of the first

four and last four elements were mixed and diluted to a volume

of one liter so that the resulting two mixed stock solutions

contained ten micrograms of each element per milliliter. A dilute

solution of Gold of the same concentration was prepared by

dilution of a stock solution containing 3.5 g./1. Auc13 • The

chelating agent, 8-hydroxyquinoline (exine), was prepared at

various concentrations in acetic acid. Phenolphthalein and

2-naphthol were used in powder form.

b. Apparatus. All Atomic Absorption measurements were made

on a standard Perkin Elmer Atomic Absorption Spectrophotometer,

Model 303, using the air-acetylene single slot burner head and

null meter readout.

~. Standards. Solution standards were prepared covering the

concentration range .02~10 ppm by dilut~on of proper aliquots of

the two mixed metal stock solutions. Calibration curves were then

prepared for each element by measuring the relative percent

absorption of each of the standard solutions at the appropriate

wavelengths. Instrument parameters used are given in Table X.

To study the effect on the standard curves of the organic

reagents used in the coprecipitation studies, additional sets of

standard solutions were prepared, one using water which had been

saturated with phenolphthalein and others containing various

amounts of 8-hydroxyquinoline.

2. Results and Discussion

11

In coprecipitation studies the concentration of metal ions

must be kept sufficiently low as to not exceed the solubility

product constant of the metal chelates, otherwise precipitation

not coprecipitation would be taking place. A study of this sort

is therefore largly limited by the analytical method by which the

quantities of the trace components are determined.

a. Detection Limits. Figures (7-16) show the calibration

curves for the elements of interest in the concentration ranges

for which the most accurate absorption measurements could be

obtained using the most sensitive instrument settings. Concen­

tration values are plotted against percent absorption or absorbance

depending on which gave the most linear curve. The lowest optimum

working ranges were found to be: (1) Cd and Zn .01-0.1 ppm (2) Cu,

Co, Mn, Ag, Au 0.1-1.0 ppm (3) Pb and Ni 1-10 ppm.

b. Effect of Organic Materials. In order for the copre­

cipitation phenomenon to occur on solid organic carrier precipitates,

the:metal ions must first be tied to a large organic molecule. An

excess of various chelating agents, such as oxine, have been used

for this purpose. The effect on the accurate determination of the

trace amounts of metals by approximately a 50 fold excess of oxine

was investigated by preparing the series of solution standards to

contain 1 ml. of a 5% solution of oxine. Experiments were conducted

on a solution containing Cu, Zn, Cd, and Mn. The curves for Co, Cd,

and Mn were found to be identical with those prepared from solutions

12

containing no exine. However the relative percent absorption

values for copper and zinc were suppressed. This was found to be

caused by precipitation of the copper as the oxinate from the

solution standards of high concentration, with the possible co­

precipitation of zinc hydroxide. These results are resonable in

light of the very high formation constant of copper oxinate (105

higher than any of the other metals), and the amphoteric nature of

zinc. Since zinc is known to precipitate as the hydroxide at

about the optimum pH for coprecipitation (about 5.5), it was ex­

cluded from study by this technique. Copper on the other hand

could be used in the absence of zinc at concentrations not to

exceed 50 micrograms.

The lowest optimum working range for lead and nickel was found

to be 1-10 ppm. This would necessitate carrying out the copre­

cipitation studies of these two elements at an order of magnitude

higher concentration levels than for the other elements. Experiments

showed that solution standards containing no visible precipitate

could not be obtained for these elements above the range O.l-1 ppm.

Therefore lead and nickel, because of their poor sensitivities, had

to be excluded from study using Atomic Absorption as the means of

quantitative determination.

The column-coprecipitation technique involves the passage of

aqueous solutions of metal chelates over a column of solid organic

material. Since phenolphthalein, one of the materials used, is

slightly soluble in water, its effect on the accurate determination

of the traces of metals was determined. Figure 1 shows that the

small amount of dissolved phenophthalein had no effect on the

calibration curve for zinc. All the other elements of interest

.20

.16

Q)

(.) .12 c:: t1l

.0 !-< 0 fl.l

~

.08

.04

13

0 standards in distilled water

~ standards containing phenolphthalein

0.2 0.4 0.6 0.8 1.0 Zinc Concentration, ppm

Figure 1. EFFECT OF ORGANIC MATERIALS ON STANDARD CURVE FOR ZINC

were investigated and the presence of dissolved phenolphthalein

found to be negligible.

B. Indirect Determination of Trace Amounts of Chelating Agent

14

For the quantitative determination of small amounts of chelating

agents during coprecipitation studies, previous workers (30,37)

have used ultraviolet absorption spectrophotometry. The present

study has defined a new analytical technique. During the invest­

igations of the effect of oxine on the calibration.·curves of the

various elements, it was observed that an t1indirect" quantitative

method, using Atomic Absorption Spectrophotometry, could be set

up for the determination of trace amounts of chelating agents.

In aqueous solutions, oxine forms chelate complexes with

metals which can be extracted into organic solvents. Since the

amount of particular metal extracted is governed by the concen­

tration of the chelating agent, a direct relationship can be

obtained between the reduction in the atomic absorption signal for

the metal in the aqueous phase and the concentration of the chelating

agent.

1. Experimental

Since 8-hydroxyquinoline is an ampholyte, close control of

the pH is very important in the extraction or precipitation of the

jydroxyquinolates. In the present work the system was buffered to

a pH of 6.5 with acetate.

A measured excess of metal ion (about 10 ppm copper solution

was used in this study) was added to s.eparatory funnels. Various

amounts of oxine in acetic acid solution were then added covering

15

the concentration range of about 0-5 ppm, and the pH brought up

to 6.5 by the addition of solid ammonium acetate. The aqueous :

phases were then extracted with methyl isobutyl ketone and placed

in volumetric flasks. The organic layers were washed with a

dilute solution of ammonium acetate and the washings added to the

flasks. The solutions were diluted to volume, mixed, and the

relative percent absorptions measured.

2. Results and ~iseussion

Figure 2 shows the linear attenuation of the absorption

signal for the aqueous solution of copper as the amount of oxine

is increased. Since the chelating agent reduces the amount of

absorption of metal in direct proportion to its concentration,

this indirect method can be used to quantitatively measure trace

amounts of chelating agent.

Alternately, the amount of absorption of the organic phase

could have been measured and the concentration of chelating agent

related to the increase in metal signal. Generally the sensitivity

of determinations performed in organic solvents is greater than

those in aqueous solutions. However at the time of this work, the

Atomic Absorption unit was not equipped to aspirate organic solvents.

Copper was the only metal used in this aspect of the present

study. Others should suffice, provided their hydroxyquinolates are

soluble in the organic solvent employed. Other solvents such as

chloroform or ethyl acetate could probably be used, however Sandell

(28) points out that the hydroxyquinolates of Ga, Mg, W, Ag, and Au

are not extractable into chloroform and those of Cd,and Zn precipitate

16

out of the chloroform phase as they become hydrated.

No study was made to determine the optimum conditions for

complete extraction of the metal because this indirect technique

is the reverse to that usually used in solvent extraction in that

an excess of metal ion is added rather than of chelating aga.nt.

As long as the conditions of extraction are held constant, it is

unimportant for the maximum amount of metal to be extracted.

In all probability this technique could be extended to many

other chelating agents. The concentration ranges of the species

being determined can easily be extended by varying the amount of

excess metal present.

17

14

12

c:1o 0

·.-I 4-J p. 1-l 0 Ul

~ 4-J d 8 <lJ (.)

1-l <lJ

p..,

<lJ >

•.-I 4-J C\1

,....; 6 <lJ

P:i

4

2

5 10 15 Ho1arity Oxine x 106

20 25

Figure 2. ATTENUATION OF COPPER ABSORPTION SIGNAL BY OXINE

18

IV. COLUMN-COPRECIPITATION STUDIES

Previous workers (30,37) have studied the coprecipitation of

trace amounts of metals using various combinations of chelating

agent and carrier precipitate. Their work has shown the oxine­

phenoEphthalein and oxine-2-naphthol systems m be very good in

producing complete coprecipitation. These systems were therefore

chosen for studies in the feasibility of a column-coprecipitation

technique. Experiments were performed to determine the factors

affecting the retention and elution of metal"oxinates on columns

of solid organic carrier precipitates (coprecipitants).

where

From the equation

Me+n

Me+n + n RKe ----- Me(Ke) n

= metal ion of oooidation

+ + n R

number

~e = organic chelating agent

Me(Ke) n = metal chelate

R+ = hydrogen ion

Equation (l)

n '

it is apparent that the concentration of the chelating agent and

the pH are very important factors in the coprecipitation pr&cess

if it is the metal chelate species that is being coprecipitated.

Therefore these two factors (and others) were examined in an

attempt to obtain the concentration/separation of metals by a

column-coprecipitatian technique.

19

A. General Experimental Procedure for Coprecipitation

Standard solutions of Cu, Co, Cd, and Mn (10 mcg./ml.) were

prepared by dilution of suitable stock solutions. Oxine was

dispensed from standard solutions containing 100, 50, and 5 milli­

grams per milliliter in acetic acid.

Test solutions were prepared by adding to 75 ml. of distilled

water, 20 meg. of one of the above metals, and the desired level

of excess exine. The pH was then adjusted by the addition of dilute

HCl or NH4oH. In no case was there a visible sign of a precipitate

forming since the metal concentration was so small. A blank

solution was also prepared containing the same ingredients except

t~ metal ions.

A polyethylene holder tube with an end filter disc was packed

with three grams of the carrier precipitate (in some experiments

the carrier precipitate was used directly from the reagent bottle

and in others it was freshly prec&pitated from alcoholic solution).

The column of coprecipitant was conditioned by passing through it

about 20 ml. of the blank solution, the filtrate being discarded.

Next the test solution was passed through at a rate of about

1 ml./min. with the aid of suction. The column was then washed

with 10 ml. of the blank solution. The test solution and washings

were collected in a 100 ml. volumetric flask and made up to volume

with distilled water. The amount of metal escaping coprecipitation

was determined by measuring the relative percent absorption of

the solutions , using Atomic Absorption, and converting to concen­

tration of metal by using the standard curves.

B. Results and Discussion

Nearly 100 pieces of data were taken under a variety of

conditions for the two carrier precipitate systems. Various

experimental conditions were investigated such as the amount

of earrier used, physical form of the carrier, oxine concen­

tration and the pH.

1. Oxine-phenolphthalein system

Table I shows the data obtained for the coprecipitation

20

of copper oxinate using a 1000 fold excess oxine and a column of

solid phenolphthalein as carrier, in which the pH was varied and

the percentage retention determined by Atomic Absorption. The

same data is presented graphically in Figure 3 and shows a

symB!etrieiH sigmoid curve when percent coprecipi ta tion is plotted

vs. pH. A maximum percentage retention of only 63% was attained.

In an attempt to increase the percent of metal retained,

experiments were carried out on the amount and physical form of

the carrier precipitate. Table II shows the non-dependence of

percent coprecipitation on carrier weight when the quantity of

material used to make up the column is varied from 1 to 5 grams.

Apparently gram quantities of carrier are well in excess of the

amount needed to coprecipi tate all the metal oxinate •

As the adsorptive properties of the carrier precipitate may

play a significant role in the column-coprecipitation technique,

attempts were made to obtain a column of very fine-grained phenol­

phthalein by freshly precipitating it from an alcoholic solution'.

pH

4

4.5

5

5.5

5.75

6

6.5

7

TABLE I.

RETENTION OF ~RACE AMOUNTS OF COPPER OXINATE BY PHENOLPHTHALEIN USING 1000 FOLD EXCESS OXINE

Quantity of Qua11tity Found Metal Taken, meg. in Filtrate, meg.

20 18.8

20 18.6

20 18.0

20 16.4

20 12.0

20 8.6

20 7.8

20 7.4

21

Percent Retained

6

7

10

18

40

57

61

63

c 0

·.-(

.u cO .u ·.-(

0.. ·.-(

0 Q)

~ 0.. 0 ()

.u c Q)

0 ~ Q)

A-1

22

70

60

50

40

30

20

10

4 5 6 pH

7 8

Figure 3. EFFECT OF pH ON PERCENTAGE COPRECIPITATION OF COPPER OXINATE AT A 1000 FOLD OXINE AND PHENOLPHTI~LEIN AS CARRIER

TABLE II.

EFFECT OF CARRIER WEIGHT ON THE COPRECIPITATION OF COPPER OXINATE USING PHENOLPHTHALEIN AND 1000 FOLD EXCESS OXINE

Grams of carrier used % Coprecipitation

1 60

2 60

3 61

4 6o

5 60

pH 6.5

23

24

Results were unsucessful because the very fine and gummy-textured

precipitate could not be transfered to the column apparatus.

When the phenolphthalein solid phase is formed by precipitation

from alcoholic solution, the very fine precipitate begins to

coagulate almost immediately. After standing for about 20 minutes

this material was collected on the column and used for coprecipitation

of copper oxinate. Table III indicates that a phenolphthalein

precipitate prepared in this manner is less effective in its co­

precipitation ability than solid phenolphthalein used directly from

a reagent bottle. Apparently coagulation had extensively decreased

the available surface area, thus indicating the possibility that

adsorption is an important factor in the column-coprecipitation

process. Since the percentage retention of copper oxinate using

phenolphthalein as carrier could not be improved, a more effective

carrier for the column technique was sought.

2. Oxine-2-Naphthol system

Tables IV-VII show the pH vs. percentage coprecipitation data

for four metal oxinates using a 1000 fold excess oxine and 2-naphthol

as carrier. The percentage retention of copper was substantially

increased over that using phenolphthale~n; complete retention was

obtained for the other metals. A summary of th~ data is presented

in Figure 4 accentuating the concentration/separation possibilities

existing for the four metals. Since the coaplete coprecipitation

takes place within very narrow pH ranges, it is possible to separate

the metals by careful adjustment of acidity. The anomalous behavior

of copper oxinate was not totally unexpected in light of the

TABLE III.

A COMPARISON OF THE COPRECIPITATION ABILITY OF SOLID PHENOLPHTHALEIN TO THAT PRECIPITATED FROM ALCOHOLIC SOLUTION

pH:f of Solution

4

5

6

% Coprecipitation

Phenolphthalein Solid precipitated

Phenolphthalein from Alcohol

6 6

10 7

57 29

20 meg. copper, 1000 fold oxine

25

pH

1

2

2.5

2.75

3

3.1

3.25

3.5

TABLE IV.

RETENTION OF TRACE AMOUNTS OF COPPER OXINATE BY 2-NAPHTHOL USING 1000 FOLD EXCESS OXINE

Quantity of Metal Taken, meg.

20

20

20

20

20

20

20

20

Quantity Found in,Filtrate, meg.

20

18.6

14

10

3.6

2.8

3.0

9.0

Percent Retained

0

7

30

50

82

86

85

55

26

pH

2.0

3.0

3.2

3.4

3.6

3.8

4.0

5.0

TABLE V.

RETENTION OF TRACE AMOUNTS OF COBALT OXINATE BY 2-NAPHTHOL USING 1000 FOLD EXCESS OXINE

Quantity of Quantity Found Percent Metal Taken, meg. in Filtrate, meg. Retained

20 20 0

20 19 5

20 15.2 24

20 11 45

20 7.4 63

20 4.2 79

20 0 100

20 0 100

27

pH

3.0

3.5

4.0

4.5

4.6

4.7

4.8

4.9

5.0

5·5

6.0

7.0

TABLE VI.

:RETENTION OF TRACE AMOUNTS OF CADMIUM OXINATE BY 2-NAPHTHOL USING 1000 FOLD EXCESS OXINE

Quantity of Quantity Found Percent Metal Taken, meg. in Filtrate, meg. Retain.ed

20 20 0

20 20 0

20 20 0

20 20 0

20 14 30

20 12 40

20 10.6 47

20 8.0 80

20 0 100

20 0 100

20 0 100

20 0 100

28

pH

4.0

5.0

5.2

5.4

5.6

5.8

6.0

TABLE VII.

RETENTION OF TRACE AMOUNTS OF MANGANESE OXINATE BY 2-NAPHTHOL USING 1000 FOLD EXCESS OXINE

Quantity of Quantity Found Percent Metal Taken, meg. in Filtrate, meg. Retained

20 20 0

20 18 10

20 8.4 58

20 1.0 95

20 0.5 97.5

20 0 100

20 0 100

29

80

c: 0

•r-l ~

60 C1l ~ •r-l p.

•r-l 0 Q)

1-l p. 0 u. ~ c:

40 Q)

u 1-l Q)

p.,

20

0 copper

A cobalt

0 cadmium

• manganese

2 3 4 5 6 7 pH

Figure 4. EFFECT OF pH ON THE COPRECIPITATION RECOVERY ANJ) SEPARATION OF FOUR METALS WITH OXINE AND 2-NAPHTHOL \}I

0

31

difficulty experienced by other workers (27) in attaining complete

coprecipitation by the usual alcoholic coprecipitation procedure.

In order to increase the versatility of the column-coprecip-

itation technique, experiments were conducted on the effect of

various levels of excess exine on the percentage coprecipitation.

Figure 5 shows the data obtained for cadmium oxinate at three

different concentration levels of exine. By adjustment of exine

level, the pH range for complete coprecipitation can be shifted

along the pH axis thus allowing additional opportunity for effecting

separation of the metals. The other oxinates would be expected to

exhibit the same general type of behavior upon changes in the

chelate concentration.

The ability Gic separate metal chelates by this method appears

to be directly related to the chelate stability constants. From

equation (1) we can define an equilibrum constant Km as follows:

Km [M(Ke)J [H+] n

= F _____ f _____ Me+n] HK3 n

Equation (2)

Km = ---~-c~~J~---[HKe]n

Equation (3)

where Dm represents the distribution ratio for the metal.

The distribution coeffic~ent is then given by:

Dm Equation (4)

32

Writing equation (4) in logarithmic form:

log Dm = log Km + n log HKe + n pH

When the percent of metal extracted (coprecipitated) is 50%

the first term is equal to zero. If we consider a constant excess

of reagent (HKe), and define p~ as the pH of 50% extraction,

at half extraction we have:

1 plL, = - log Km + log HKe

!2 n

Thus the pH at half extraction is a constant and for the same

concentration of a given chelating agent the magnitude of the p~

is dependent only on the valence of the ion (n) and the stability

constant. For a series of metals having the same valence, pH~

should vary directly with the chelate stability constant, and

the magnitude of the value should indicate the order of stability

of the chelates. From equation (4) it is apparent that the more

stable the chelate thelower will be the pH of 50% extraction.

Table VIII shows the correlation of stamility constants for

the chelates used in this study with the experimentally obtained

p~ values (taken from Figure 4). There is good qualitative agree­

ment and the order of stability is shown to be:

Cu > Co > C d > Mn

This agrees with the work of Mellor and Maley {22) who have shown

that the stability of the complexes .of bivalent metail. ions follows

the order

Pd > Cu :> Ni > Pb > Co> Zn > Cd > Fe> Mn > Mg

irrespective of the nature of the ligands involved.

80

t:l 0

•.4 -1-1 <U

-1-1 60 •.4 p.

•.4 (,) 4) 1-1 0. 0 u

-1-1 40 t:l 4) (,)

1-1 (I)

Il-l

20

0 1000 fold oxine

~ 500 fold oxine

[J 100 fold oxine

2 3 4 5 6 7 pH

Figure 5. PERCENTAGE COPRECIPITATION OF CADMIUM OXINATE AS A FUNCTION OF AMOUNT OF EXCESS OF COMPLEXING AGENT

TABLE VIII.

CORRELATION OF CHELATE STABILITY CONSTANTS WITH EXPERIMENTAL p~ VALUES (pH of half coprecipitation)

pH~ (exp)

Cu(ox) 2 23.4 2.?5

Co(ox)2 17.2 3.45

Cd(ox) 2 13.4 4.75

Mn(ox) 2 12.6 5.20

* Taken from "Stability Constants of Metal-Ion Complexes" by Sillen, L.G., and Martell, A.E., Chem. Soc. (London) Spc. Publ. No. 17 (1964)

35

It has been demonstrated that the column-coprecipitation

technique can be useful in the concentration and separation of

important transition metals. Another aspect of the present

study was to investigate its potential for the recovery of

precious metals from very dilute solutions. Test solutions,

containing 0.2 ppm silver were prepared and carried through the

coprecipitation procedure previously described.. Figure 6 shows

that complete recovery was obtained using 1000 fold excess oxine

(based on AgOx) with 2-naphthol as carrier. Attempts to apply

the same method to dilute solutions of gold failed due to the

standard solutions of gold, containing oxine, showing a pro­

nounced pH effect. Coprecipitation was believed to have taken

place over the pH range studies, however no quantitative dat~

could be obtained using Atomic Absorption. Table IX shows the

suppression in absorption signal found for a 0.75 ppm gold stand­

ard containing exine as the pH was varied from l to 7. At pH

values above 4.5, where no suppression of signal took place, the

percentage coprecipjjtation was of the order of 70%.

A final phase of this work was to determine if the presence

of an organic carrier precipitate was really necessary for the

recovery of trace amounts of metal chelates from dilute solutions.

Is true coprecipitation taking place, or could any material with

a large surface area serve equally well in retaining the metal

chelates? A suspension of macerated filter paper was passed

through the column apparatus until a tightly packed column of

paper pulp was obtaimed. Three test solutions of cadmium containing

a 1000 fold excess oxine were prepared and adjusted to pH values

of 4.5, 4.75, and .5.0. When these were carried through the

coprecipitation procedure previously described, zero percent

coprecipitation was found for each solution. When 2-naphthol

was used as the column material for the same three solutions,

percentage coprecipitation was 0, 50, and 100 percent respectively.

80

t:l 0

•r-1 .jJ (1j

60 .jJ

•r-1 p,

•r-1 u w l-1 p, 0 u .jJ 40 t:l w u l-1 w ~

20

2 3 4 5 6 7 pH

Figure 6. THE COPRECIPITATION RECOVERY OF SILVER WITH OXINE AND 2-NAPHTHOL

TABLE IX.

THE RELATIVE PERCENT ABSORPTION OF STANDARD SOLUTIONS OF GOLD AS A FUNCTION OF pH

pH

1

2

3

4

5

6

7

0.75 ppm gold standard

oxine - 1 mg./ml.

Relative Percent Absorption no oxine with oxine

16.5 16.5

16.5 12.0

16.5 4.6

16.5 9.6

16.5 16.5

16.5 16.5

16.5 16.5

39

V. CONCLUSIONS

Extensive research has be~n carried out on the ooprecipitation

of trace amounts of metals by precipitating an organic carrier

coprecipitant from an alcoholic solution in the presence of an

aqueous solution of trace metals and chelating agent (4,30,37).

The presence of a metastable liquid phase, formed as the alcoholic

carrier solution is mixed with the aqueous solution, has been

observed and it has been suggested that the microcomponents are

extracted by this transient liquid which in turn is mechanically

trapped by the carrier during precipitation (3?).

The results of this study indicate that the recovery of trace

amounts of metal chelates from very dilute solutions is just as

effective using a ''column" of solid organic material as the usual

procedure of precipitating the carrier from an alcoholic solution.

Preliminary experiments with different physical foxms of the carrier

precipitate indicate adsorption as a possible mechanism in the

column-coprecipitation process. Investigations of the coprecipitation

ability of phenolphthalein and 2-naphthol for copper oxinate,

indicate 2-naphthol to be superior. Further studies with the oxine-

2-naphthol system showed that complete recovery and separation was

possible for the oxinates of copper, cobalt, eadmium, and manganese

by careful adjustment of the pH and excess exine concnetration. The

complete recovery of trace amounts of silver was also shown to be

possible with this system. Further research will doubtless reveal

the applicability of the technique for many other metals.

40

The separation of metals by this method appears to be based

on the difference in stability cQnstants of the metal chelates.

Good qualitative agreement was found between the experimental p~

values for four metal oxinates and their stability constants.

In the past, the quantitative determination of trace elements

in coprecipi~tion studies has been accomplished with emission

spectroscopy, colorimetric methods, or radioaative tracers. Eaeh

of these methods has several d.isadvantages. In the present study

investigations were carried out on the usefulness of a relatively

new analytical method, Atomic Absorption Spectrophotometry, for

determining the extent of coprecipitation. Experiments have shown

the method to be relatively free from interference by some reagents

used in coprecipitation studies. It is a rapid method not requiring

prior chemical separations or extensive sample treatment as w:i.th

colorimetric methods. However its sensitivity limitations are •

disadvantage·; lead and nickel could not be included in the present

work due to poor sensitivity.

In coprecipitation research, it is desirable to study the

behavior of several elements simultaneously. Although Atomic

Absorption has this desirable inherent capability of multielement

anal~sis on the same test solution, advantage could not be taken

of this due to insufficient sensitivity. Determinations had to be

carried out on the elements, singly, because the extra exine

concentration needed to give a high level of excess for several

elemente simultaneously, would precipitate out at the higher pH

values where optimum coprecipi tation occured. This ,oal..d have

been overcome if the concentration of metal ion could have been

41

.owered, thus lowering the concentration of chelating agent required

;o give the desired level of excess. However the concentration of

metal ion could not be lowered since no additional increase in sen­

sitivity could be attained.

Work with Atomic Absorption during this study has disclosed a

novel application of the technique for the quantitative uindirect 11

determination of trace amounts of chelating agents. Chelates,

many times, form complexes with metals in aqueous solutions which

can be extracted into immiscible organic solvents. The amount of

metal extracted is controlled by the concentration of the chelating

agent. In this work, it has been observed that if an excess of

metal ion is added to a series of standard solutions of chelating

agent, and the solutions extracted with an organic solvent, a

direct relationship can be observed between the reduction in Atomic

Absorption signal for the metal in the aqueous phase and the con­

centration of the chelating agent. The concentration ranges of

the chelating species being determined can readily be extended by

varying the amount of excess metal present.

BIBLIOGRAPHY

1. Dehm, R.L., Dunn, W.G., and Loder, E.R., Anal. Chem. 33 , 607 (1961)

2. Farmer, V.C., Spectrochem. Acta., ~ , 224 (1950)

3. Heggen, G.E., and Strock, L.W., Anal. Chem. 25 9 859 (1953)

4. Kuznetsov, V.I., Zhurn. An~~. Khim. ~, 199 (1954)

5. Ibid., 10 , 32 (1955) - . 6. Kuznetsov, V.I., and Myosoedova, G.V., Zhurn. Anal. Khim.

!Q 9 21$1 (1955)

7. Kuznetsov, V.I., Session of USSR Academy of Sciences on Peaceful Uses of Atomic Energy, Chemical Section, p. 177 (1955)

8 .. Kuznetsov, V.I., and Papaushina, L.I., Zhurn. Anal.., Khim. ll ' 686 (1956)

9. Kuznetsov, V.I., Ibid., 13 9 79 (1958)

42

10. Kuznetsov, V.I .. , and Myosoedova, G.V., Tr. Komia. po Analit. Kbim. Akad. Nauk. SSSR Inst. Geokbim. i A.na1it. Khim.. 2. ' 76 (1958)

11. Ibid., P• 89

12. Kuznetsov, V.I.., and Aki:miva, T.G., Radiokhim. 2 , 357 (1960}

13. Ibid., 2 , 426 (1960)

14. Ibid., l , 737 (1961)

15. Ibid., 4 , 188 (1962)

16. Ibid., l , 93 (1963)

17. Kuznetsov, V .. I., Myosodova, G.V., Akimova, T.G. and Nikolskaya, I.V., Tr. Komia. po Analit. Khim. Akad. Nauk. SSSR Inst. Geokhim. i Analit. Khim. 12 9 296 (1965)

18. Ibid., P• 279

19. Kuznetsov, V.I., Gorshkov, v.v., and Orlova, L.P., Agrokbim. E. t 118 (1964)

20. Kuznetsov, V.I., and Slovera, T.V., Dokl. Akad. Nauk. SSSR 167 ' 1063 (1966)

21. Lai, M.G., and Weiss, H.V., Anal .. Chem. 34 , 1012 (1962)

22 .. Mellor and Maley, Nature 159 9 370 (1947)

43

23. Mitchell, R.L., and Scott, R.O., J. Soc. Chem. Ind. 62, 4 (1943)

24. Ibid., 66 , 330 (1947)

25. Mitchell, R.L., Commonwealth Bureau of Soil Science, Tech. Comm. No. 44, Harpended, England, 1948

26. Mitchell, R.L., and Scott, R.O., Spectrochem. Acta. 2 ,367 (1948)

27. Pickett, E.E., and Hankins, B.E., Anal. Chem. ZQ, 47 (1958)

28. Sandell, E.B., "Colorimetric Determination of Traces of Metals", Chemical Analysis Series, Vol. III., Third Ed., Inter­scienceoPublishers, Inc., New York (1959)

29. Smit, J. and Smit, J.A., Anal. Chem. ~ , 274 (1953)

30. Tappmeyer, W.P., and Pickett, E.E., Anal. Chem. 34, 1709 (1962)

31. Troitskii, K.V., Zhurn. Neorg. Khim.!, 1104 (1956)

32. Weiss, H.V., and Lai, M.G., Anal. Chem. 32, 475 (1960)

33. Weiss, H.V., and Shipman, W.H., Ibid., 34 , 1010 (1962)

34. Weiss, H. V., Lai, M.G., and Gillespie, A., Anal. Chem. Acta. 2.5 t 550 (1961)

35. Weiss, H. V., and Lai, M.G., Talanta~~ ,72 (1961)

36. Ibid., J. Inorg. Nucl. Chem. 17 t 366 (1961)

37. Williams, J.C., Ph.D. Thesis, University of Missouri (1964)

44

APPENDIX

TABLE X.

INSTRUMENT PARAMETERS

Scale Elements Settings Mn Co Cu Pb Ni Ag Au Cd Zn

Scale Expansion lOX lOX lOX lOX lOX lOX lOX lOX & lX lOX & lX

Meter Response 3 2 3 2 3 2 2 2 2

Slit Selector 2 3 4 4 3 4 5 4 4

Grating Counter 280 241 325 217 232 328 243 229 214

Air Flowmeter 9 9 9 9 9 9 9 9 9

Acetylene Flowmeter 9 9 9 9 9 9. 7.5 9 9

46

80 Mn 2795 & 2798 A Q 0

•.-I .J-J 0.. 1-1 0 Ul 60 ~ -l-1 Q <I) C)

1-1 <I)

P-1

Cl) 40 > •.-I .J-J cU

.--l <I)

~

20

0.2 0.4 0.6 0.8 1.0 Manganese Concentration, ppm

Figure 7 • STANDARD CURVE FOR MANGANESE

(\) C) c: a:s

.a !--1 0 til

~

.20 Co 2407 A

.15

.10

.05

0.2 0.4 0.6 Cobalt Concentration, ppm

Figure 8. STANDARD CURVE FOR COBALT

47

0.8 1.0

48

.08 Cd 2288 A

.06

.04

.02

0.2 0.4 0.6 0.8 1.0 Cadmium Concentration, ppm

Figure 9. STANDARD CURVE FOR CADMIUM

25 Cd 2288 A

Q 20 0 •.-l .u 0.. 1-1 0 Cl)

~ .u Q 15 C) (.)

1-1 C)

t:t< C)

:> ·.-l .u cO

r-1 10 C) p:::

5

.02 .04 .06 .03 Cadmium Concentration, ppm

Figure 10. STANDARD CURVE FOR CADMIUM

50

35 Ni 2320 A

30

r:: 0 25 •.-I l-1 p.. l-1 0 Cl.l

~ l-1 s:: <l) 20 ()

l-1 <l)

P-<

<l)

:> •...t l-1 m

r-1 <l) 15 ~

10

5

2 4 6 8 10 Nickel Concentration, ppm

Figure 11. STANDARD CURVE FOR NICKEL

51

70 Ag 3221 A

60

s:: so 0 •ri -I.J 0.. H 0 C/l

~ -I.J ~

40 (!)

0 H (!)

p.,

(!)

:> •ri -I.J C\1

...-1 30 (!)

0:::

20

10

0.2 0.4 0.6 0.8 1.0 Silver Concentration, ppm

Figure 12. STANDARD CURVE FOR SILVER

52

.12 Pb 2170 A

.10

.08

.06

.04

.02

2 4 6 8 10 Lead Concentration, ppm

Figure 13. STANDARD CURVE FOR LEAD

53

25 Zn 2138 A

Q 20 0 ·~ +J p.. H 0 Ul

,.0 ~

+J Q 15 <lJ (.)

H <lJ p..

<lJ l>

•.-I +J cd

.....-! 10 (!)

~

5

.02 .04 .06 .08 0.1 Zinc Concentration, ppm

Figure 14. STANDARD CURVE FOR ZINC

54

40 Cu 3247 A

l::l 0

•.-I .u 0, l-1 0

30 UJ ,.0 <! .u l::l (!) (.)

l-1 (!)

P-1

(!)

> 20

·rl .jJ

<d r-l (!) p::

10

0.1 0.2 0.3 0.4 0.5 Copper Concentration, ppm

Figure 15. STANDARD CURVE FOR COPPER

55

40

c: 0

•.-l .j.J

0... 1-1 0

30 Iii) ,..a < .j.J

c: Q)

0 1-1 Q)

P.r

Q) 20 >

•.-I .j.J

til ~ Q) p::

10

"'

0.6 1.2 1.8 Gold Concentration ppm

Figure 16. STANDARD CURVE FOR GOLD

ACKNOWLEDGMENTS

The author would like to take this opportunity to thank

his advisor, Dr. Wilbur P. Tappmeyer, for his suggestions and

guidance during the course of th~s study.

Thanks also goes to Dr. Ernst A. Bolter of the Geology

Department for permission to use their Atomic Absorption

instrument.

For their continuous encouragement and support throughout

his educational career, the author gratefully acknowledges his

parents, Mr. and Mrs. Paul R. Schucker.

56

57

VITA

The author was born in McConnellstown, Pennsylvania on

October 29, 1936. He was graduated from Huntingdon High School

in June 1954. In September of 1954 he entered Juniata College,

Huntingdon, Pa. and was graduated in 1958 with a B.S. in Chemistry.

During the years 1958-1962 he was employed as a chemist by

the Pennsylvania Railroad Company Test Department, Altoona, Pa.

From 1962-1965 he worked in the Materials Science Center of

Cornell University, Ithaca, N.Y. He began graduate study at the

University of Missouri at Rolla, Rolla, Mo. in September of 1965.