STUDIES ON THE USE OF ADSORPTION &

ADVANCED OXIDATION PROCESS FOR the

TREATMENT OF TEXTILE INDUSTRY WASTE

WATER

A thesis submitted towards partial fulfillment of the requirements for the degree of

MASTER OF ENGINEERING IN CHEMICAL ENGINEERING

Submitted by

SAMYA SUBHRA DAS

Class Roll No: 001310302002

Exam Roll No: M4CHE1502

Registration No: 124699 of 2013-14

Under the Guidance of

Dr. Chiranjib Bhattacharjee

Professor & former Head of the Department

Department of Chemical Engineering

Jadavpur University

DEPARTMENT OF CHEMICAL ENGINEERING JADAVPUR UNIVERSITY

Jadavpur, Kolkata-700032

MAY 2015

FACULTY OF ENGINEERING AND TECHNOLOGY DEPARTMENT OF CHEMICAL ENGINEERING

JADAVPUR UNIVERSITY

CERTIFICATE OF RECOMMENDATION

This is to certify that the thesis entitled STUDIES ON THE USE OF

ADSORPTION & ADVANCED OXIDATION PROCESS FOR THE

TREATMENT OF TEXTILE INDUSTRY WASTE WATER is a bonafide

work carried out by Samya Subhra Das under my supervision and guidance for

partial fulfillment of the requirement of Master of Engineering in Chemical

Engineering, during the academic session 2013-2015

-------------------------------------------- ---------------------------------------------

Dr. Chiranjib Bhattacharjee Dr. Chandan Guha

Project Supervisor Professor & HOD

Professor & former-HOD Department of Chemical Engineering

Department of Chemical Engineering Jadavpur University, Kolkata-32

Jadavpur University, Kolkata-32

--------------------------------------------

DEAN -FET

Jadavpur University,

Kolkata-700 032

FACULTY OF ENGINEERING AND TECHNOLOGY DEPARTMENT OF CHEMICAL ENGINEERING

JADAVPUR UNIVERSITY

CERTIFICATE OF APPROVAL

This foregoing thesis is hereby approved as a credible study of an engineering

subject carried out and presented in a manner satisfactorily to warranty its

acceptance as a prerequisite to the degree for which it has been submitted. It is

understood that by this approval the undersigned do not endorse or approve any

statement made or opinion expressed or conclusion drawn therein but approve the

thesis only for purpose for which it has been submitted.

-----------------------------------------------

Committee of final examination -----------------------------------------------

for evaluation of Thesis

-----------------------------------------------

-----------------------------------------------

DECLARATION OF ORIGINALITY AND COMPLIANCE OF ACADEMIC ETHICS

I hereby declare that this thesis contains literature survey and original research work by the undersigned candidate, as part of his Master of Engineering in Chemical Engineering studies during academic session 2013-2015.

All information in this document has been obtained and presented in accordance with academic rules and ethical conduct.

I also declare that, as required by this rules and conduct, I have fully cited and referred all material and results that are not original to this work.

Name: SAMYA SUBHRA DAS

Roll Number: 001310302002

Exam Roll No: M4CHE1502

Thesis Title: STUDIES ON THE USE OF ADSORPTION & ADVANCED OXIDATION PROCESS FOR THE TREATMENT OF TEXTILE INDUSTRY WASTE WATER

SIGNATURE: DATE:

(SAMYA SUBHRA DAS)

ACKNOWLEDGEMENT I consider it as my privilege to express gratitude and respect to all those who

guided and inspired me in the completion of my M.E. project. The undertaking of

this project inculcated a strong sense of research inside me and I also came to

know about many new things.

First of all, I would like to acknowledge and extend my heartfelt gratitude to

Dr. Chiranjib Bhattacharjee (Professor & Former HOD, Department of Chemical

Engineering, Jadavpur University) for his exemplary guidance during the

undertaking of this project entitled, STUDIES ON THE USE OF ADSORPTION

& ADVANCED OXIDATION PROCESS FOR THE TREATMENT OF

TEXTILE INDUSTRY WASTE WATER.

I would like to take this opportunity to thank Mr. Shubhrajit Sarkar (PhD

research scholar, Chemical engg. dept. JU) for his constant encouragement and

helpful advice in completion of this project work. I would also like to extend my

gratitude to my co-researcher Mr. Diptadip Paul (B.E. Chemical engg, JU) & all

the seniors of the Membrane Separation Lab (Chemical engg dept. JU) for

supporting me whenever it was needed.

My very special thanks to my parents & my little brother, whom I owe

everything I am today. Their unwavering faith & confidence in my abilities have

always helped me to overcome all the problems of my life. Thanks to all of my

friends for their constant love & support.

Finally, I would like to take the opportunity to thank all my teachers and

support staff of the Chemical Engineering Department, Jadavpur University,

Kolkata.

CONTENTS CHAPTER NO & TOPIC/SUB-TOPIC PAGE NO

1. INTRODUCTION 1 - 29

1.1. Waste water: A brief review 4

1.1.1. Origin 5

1.1.2. Waste water constituents 6

1.1.3. Wastewater quality indicators 6

1.2. Industrial Wastewater 7

1.2.1. Types of industrial waste water 8

1.3. Textile industry Effluents 10

1.4. Textile dye 11

1.4.1. Adverse effect of Textile Dye 15

1.5. Different wastewater treatment procedure 15

1.6. Adsorption 18

1.6.1. Different Popular adsorbents 18

1.6.2. Advantages & disadvantages of adsorption 22

1.7. Advanced Oxidation Process 23

1.7.1. Advantages & disadvantages of AOP 25

1.7.2. Classification 26

2. LITERATURE REVIEW 30 - 36

3. AIMS & OBJECTIVES 37 - 39

4. ADSORPTION 40 - 57

4.1. Materials 41

4.2. Preparation of adsorbents 41

4.3. Equipments 41

4.4. Analytical instrument 41

4.5. Methods 43

4.5.1. Effect of Adsorbent dosage 43

4.5.2. Effect of pH 43

4.5.3. Equilibrium studies 43

4.5.4. Batch kinetic studies 44

4.5.5. Analytical method 44

4.6. Results & Discussion: Effect of pH 46

4.7. Results & Discussion: Effect of adsorbent dosage 47

4.8. Results & Discussion: Effect of temperature 48

4.9. Results & Discussion: Effect of stirring speed 49

4.10. Effect of contact time and initial concentration 50

4.11. Equilibrium studies & Isotherm analysis 51

4.12. Results & Discussion: Adsorption kinetics 55

4.13. Characterization study 57

5. SONO FFENTON 60 - 69

5.1. Materials 61

5.2. Equipments 61

5.3. Experimental Methods 62

5.3.1. Effect of H2O2 dose 62

5.3.2. Effect of FeSO4 dose 62

5.3.3. Effect of pH 62

5.4. Results & discussions: Effect of solution pH 64

5.5. Results & discussions: Effect of FeSO4 dose 65

5.6. Results & discussions: Effect of H2O2 dose 66

5.7. Enhancement of dye degradation in Sono Fenton process 67

5.8. Effect of different salts on Sono Fenton 67

6. CONCLUSION 70 - 71

REFERENCES 72 - 74

List of figures

Fig no Figure details Page no

Fig I Different Stages of a textile industry 10

Fig II Molecular Structure of Reactive green 19 14

Fig III Different widely popular Adsorbents 21

Fig IV Outline of the Advanced Oxidation Process 24

Fig V Oxidation potential of different elements 24

Fig VI Electron transfer in Advanced Oxidation Process 28

Fig VII Flow chart of the work to be done 39

Fig VIII Time & RPM controlled rotary shaker 42

Fig IX UV Spectrophotometer 42

Fig X Digital pH meter 42

Fig XI Cold Centrifuge 42

Fig XII Vaccum Oven 42

Fig XIII Decoloration of RG 19 by adsorption at optimum conditions 45

Fig XIV Effect of pH on decoloration of RG19 on MTW 46

Fig XV Effect of adsorbent dosage on decoloration of RG19 on MTW 47

Fig XVI Effect of temperature on decoloration of RG19 on MTW 48

Fig XVII Effect of stirring speed on decoloration of RG19 on MTW 49

Fig XVIII Effect of contact time and initial concentration on the adsorption

of RG19 on MTW

50

Fig XIX Isotherm analysis for Langmuir model 51

Fig XX Isotherm analysis for Freundlich model 52

Fig XXI Isotherm analysis for Temkin model 53

Fig XXII Pseudo second order kinetics 56

Fig XXIII SEM image of adsorbent (a) Before adsorption (b) After

adsorption

57

Fig XXIV FTIR spectra of the adsorbent samples: after & before adsorption 57

Fig XXV Probe Sonicator System 61

Fig XXVI Decoloration of dye solution at optimum conditions at definite

time intervals

63

Fig XXVII Effect of solution pH on decoloration of RG 19 by SF 64

Fig XXVIII Effect of solution pH on decoloration of RG 19 by SF 65

Fig XXIX Effect of H2O2 dose on decoloration of RG 19 by SF 66

Fig XXX Effect of different process on decoloration of RG 19 by SF 67

Fig XXXI Effect of different salts on decoloration of RG 19 by SF 68

1

CHAPTER - 1

IntroductIon

2

The imbalance between the environment and the existence of life on the earth is due to

rapid and enormous growth of industrial civilization for meeting the needs of the tremendous rise

in human population day by day. Water is available in three different forms on the earth namely:

Ground water, Surface water & Rain water. Rain water, although is extremely pure and safe for

all purposes of our civilization, but harvesting rain water and its storage is inadequate to meet

our demand. Ground water and rain water although are available in plenty, the quality and cost of

these two forms of water have become an alarming threat to our survival. Ground water is

gradually becoming depleted and/or contaminated due to percolation. The surface water is

already contaminated by mercury, chromium, copper, nickel salts & oils & dyes etc. due to

industrial and domestic effluents discharged into the rivers and oceans through the porous bed of

soil and rocks, as also due to sliding in the mineral deposits of arsenic & other detrimental

metals.

Freshwater ecosystems are aquatic systems which contain drinkable water or water of

almost no salt content. Freshwater resources include lakes and ponds, rivers and streams,

reservoirs, wetlands, and groundwater. They provide the majority of our nation's drinking water

resources, water resources for agriculture, industry, sanitation, as well as food including fish and

shellfish. They also provide recreational opportunities and a means of transportation. In addition,

freshwater ecosystems are home to numerous organisms (e.g., fish, amphibians, aquatic plants,

and invertebrates). It has been estimated that 40% of all known fish species on Earth come from

freshwater ecosystems. Human activities are causing species to disappear at an alarming rate. It

has been estimated that between 1975 and 2015, species extinction will occur at a rate of 1 to 11

percent per decade. Aquatic species are at a higher risk of extinction than mammals and birds.

Losses of this magnitude impact the entire ecosystem, depriving valuable resources used to

provide food, medicines, and industrial materials to human beings. While freshwater and marine

ecosystems face similar threats, there are some differences regarding the severity of each threat.

Runoff from agricultural and urban areas, the invasion of exotic species, and the creation of

dams and water diversion have been identified as the greatest challenges to freshwater

environments [1]. Overfishing is the greatest threat to marine environments, thus the need for

sustainable fisheries has been identified by the Environmental Defense Fund as the key priority

in preserving marine biodiversity. Other threats to aquatic biodiversity include urban

development and resource-based industries, such as mining and forestry that destroy or reduce

natural habitats. In addition, air and water pollution, sedimentation and erosion, and climate

change also pose threats to aquatic biodiversity. Pollution has been very damaging to aquatic

3

ecosystems, and may consist of agricultural, urban, and industrial wastes containing

contaminants such as sewage, fertilizer, and heavy metals that have proven to be very damaging

to aquatic habitats and species. Metals, a major category of globally-distributed pollutants, are

natural elements that have been extracted from the earth and harnessed for human industry and

products for modern civilized world. Numerous industrial processes and human & animal

excreting produce aqueous effluents and sewer that contain heavy metals, non-metals and

organic contaminants. People are exposed to organic component through inhalation, water and

food/ ingestion. Textile industries are among those industries that discharge wastewater.

The textile industry uses high volumes of water throughout its operations, from the

washing of fibers to bleaching, dyeing and washing of finished products. On average,

approximately 200 liters of water are required to produce l kg of textiles the large volumes of

wastewater generated also contain a wide variety of chemicals, used throughout processing.

These can cause damage if not properly treated before being discharged into the environment. Of

all the steps involved in textiles processing, wet processing creates the highest volume of

wastewater. The aquatic toxicity of textile industry wastewater varies considerably among

production facilities. The sources of aquatic toxicity can include salt, surfactants, ionic metals

and their metal complexes, toxic organic chemicals, biocides and toxic anions. Most textile dyes

have low aquatic toxicity. On the other hand, surfactants and related compounds, such as

detergents, emulsifiers and dispersants are used in almost each textile process and can be an

important contributor to effluent aquatic toxicity, BOD and foaming. Several methods have been

developed for decontamination of municipal and industrial waters and wastewaters. The most

common methods for removal of contaminants from industrial effluents include chemical

precipitation, solvent extraction, dialysis, electrolytic extraction, electro-dialysis, cementation,

reverse osmosis, membrane filtration, ion exchange, adsorption and co-precipitation.

4

1.1. Waste Water: a Brief OvervieW

Wastewater, also written as waste water, is any water that has been adversely affected in

quality by anthropogenic influence. Municipal wastewater is usually conveyed in a combined

sewer or sanitary sewer, and treated at a wastewater treatment plant. Treated wastewater is

discharged into receiving water via an effluent sewer. Wastewaters generated in areas without

access to centralized sewer systems rely on on-site wastewater systems. These typically comprise

a septic tank, drain field, and optionally an on-site treatment unit.

Sewage is the subset of wastewater that is contaminated with feces or urine, but is often used to

mean any wastewater. Sewage includes domestic, municipal, or industrial liquid waste products

disposed of, usually via a pipe or sewer (sanitary or combined), sometimes in a cesspool emptier.

Sewerage is the physical infrastructure, including pipes, pumps, and screens, channels etc. used

to convey sewage from its origin to the point of eventual treatment or disposal. It is found in all

types of sewage treatment, with the exception of septic systems, which treat sewage on site.

1.1.1. Origin:

Wastewater or sewage can come from:

Human waste (faces, used toilet paper or wipes, urine, or other bodily fluids), also known

as black water, usually from lavatories;

5

Cesspit leakage;

Septic tank discharge;

Sewage treatment plant discharge;

Washing water (personal, clothes, floors, dishes, etc.), also known as greywater or sullage;

Rainfall collected on roofs, yards, hard-standings, etc. (generally clean with traces

of oils and fuel);

Groundwater infiltrated into sewage;

Surplus manufactured liquids from domestic sources (drinks, cooking

oil, pesticides, lubricating oil, paint, cleaning liquids, etc.);

Urban rainfall runoff from roads, car parks, roofs, sidewalks / pavements (contains oils,

animal feces, litter, gasoline/petrol, diesel or rubber residues, soap scum, metals from

vehicles exhaust etc.)

Seawater ingress (high volumes of salt and microbes);

Direct ingress of river water (high volumes of micro-biota);

Direct ingress of manmade liquids (illegal disposal of pesticides, used oils, etc.);

Highway drainage (oil, de-icing agents, rubber residues);

Storm drains (almost anything, including cars, shopping trolleys, trees, cattle, etc.);

Blackwater (surface water contaminated by sewage);

Industrial waste

Industrial site drainage (silt, sand, alkali, oil, chemical residues);

Industrial cooling waters (biocides, heat, slimes, silt);

Industrial process waters;

Organic or biodegradable waste, including waste from abattoirs, creameries, and ice

cream manufacture;

Organic or non bio-degradable/difficult-to-treat waste

Extreme pH waste (from acid/alkali manufacturing, metal plating);

Toxic waste (metal plating, cyanide production, pesticide manufacturing, etc.);

Solids and emulsions

Agricultural drainage, direct and diffuse.

Hydraulic fracturing

Produced water from oil & natural gas production

6

1.1.2. Wastewater constituents:

The composition of wastewater varies widely. This is a partial list of what it may contain:

Water (more than 95 percent), which is often added during flushing to carry waste down a

drain;

Pathogens such as bacteria, viruses, prions and parasitic worms;

Non-pathogenic bacteria;

Organic particles such as feces, hairs, food, vomit, paper fibers, plant material, humus, etc.;

Soluble organic materials such as urea, pharmaceutical wastes, sugars etc.:

Inorganic particles such as sand, grit, metal particles, ceramics, etc.;

Soluble inorganic material such as ammonia, road-salt, sea-salt, cyanide, hydrogen

sulfide, thiocyanates, thiosulfates, etc.;

Animals such as protozoa, insects, arthropods, small fish, etc.;

Macro-solids such as sanitary napkins, nappies/diapers, condoms, needles, children's toys,

dead animals or plants, etc.;

Gases such as hydrogen sulfide, carbon dioxide, methane, etc.;

Emulsions such as paints, adhesives, mayonnaise, hair colorants, emulsified oils, etc.;

Toxins such as pesticides, poisons, herbicides, etc.

1.1.3. Wastewater quality indicators:

Any oxidizable material present in a natural waterway or in an industrial wastewater will

be oxidized both by biochemical (bacterial) or chemical processes. The result is that the oxygen

content of the water will be decreased. Basically, the reaction for biochemical oxidation may be

written as:

Oxidizable material + nutrient + bacteria + O2 CO2 + H2O + Oxidized inorganic species

Oxygen consumption by reducing chemicals such as sulfides and nitrites is typified as follows:

S-- + 2 O2 SO4--

NO2- + O2 NO3-

Since all natural waterways contain bacteria and nutrients, almost any waste compounds

introduced into such waterways will initiate biochemical reactions (such as shown above). Those

7

biochemical reactions create what is measured in the laboratory as the biochemical oxygen

demand (BOD). Such chemicals are also liable to be broken down using strong oxidizing agents

and these chemical reactions create what is measured in the laboratory as the chemical oxygen

demand (COD). Both the BOD and COD tests are a measure of the relative oxygen-depletion

effect of a waste contaminant. Both have been widely adopted as a measure of pollution effect.

The BOD test measures the oxygen demand of biodegradable pollutants whereas the COD test

measures the oxygen demand of oxidizable pollutants. The so-called 5-day BOD measures the

amount of oxygen consumed by biochemical oxidation of waste contaminants in a 5-day period.

The total amount of oxygen consumed when the biochemical reaction is allowed to proceed to

completion is called the Ultimate BOD. Because the Ultimate BOD is so time consuming, the 5-

day BOD has been almost universally adopted as a measure of relative pollution effect. There are

also many different COD tests of which the 4-hour COD is probably the most common. There is

no generalized correlation between the 5-day BOD and the ultimate BOD. Similarly there is no

generalized correlation between BOD and COD. It is possible to develop such correlations for

specific waste contaminants in a specific wastewater stream but such correlations cannot be

generalized for use with any other waste contaminants or wastewater streams. This is because the

composition of any wastewater stream is different. As an example an effluent consisting of a

solution of simple sugars that might discharge from a confectionery factory is likely to have

organic components that degrade very quickly. In such a case, the 5 day BOD and the ultimate

BOD would be very similar since there would be very little organic material left after 5 days.

However a final effluent of a sewage treatment works serving a large industrialized area might

have a discharge where the ultimate BOD was much greater than the 5 day BOD because much

of the easily degraded material would have been removed in the sewage treatment process and

many industrial processes discharge difficult to degrade organic molecules. The laboratory test

procedures for the determining the above oxygen demands are detailed in many standard texts.

American versions include the "Standard Methods for the Examination of Water and

Wastewater.

1.2. IndustrIal waste water

Now-a-days industrial wastewater is a real threat to the mankind. Industrial bloom has

made the life of ecosystem along with water bodies miserable with their constant emission of

wastewater. Industrial wastewater can be categorized based on different kind of parameters.

8

1.2.1. Types of industrial waste water:

There are many types of industrial wastewater based on the different industries and the

contaminants; each sector produces its own particular combination of pollutants:

Iron and steel: BOD, COD, oil, metals, acids, phenols, and cyanide

Textiles and leather: BOD, solids, sulfates and chromium

Pulp and paper: BOD, COD, solids, chlorinated organic compounds

Petrochemicals and refineries: BOD, COD, mineral oils, phenols, and chromium

Chemicals: COD, organic chemicals, heavy metals, SS, and cyanide

Non-ferrous metals: Fluorine and SS

Microelectronics: COD and organic chemicals

Mining: SS, metals, acids and salts

Generally, industrial wastewater can be divided into two types: Inorganic industrial wastewater

and Organic industrial wastewater [2].

A. Inorganic industrial wastewater:

Inorganic industrial wastewater is produced mainly in the coal and steel industry, in the

nonmetallic minerals industry, and in commercial enterprises and industries for the surface

processing of metals (iron picking works and electroplating plants). These wastewaters contain a

large proportion of suspended matter, which can be eliminated by sedimentation, often together

with chemical flocculation through the addition of iron or aluminum salts, flocculation agents

and some kinds of organic polymers. The purification of warm and dust-laden waste gases from

blast furnaces, converters, cupola furnaces, refuse and sludge incineration plants, and aluminum

works results in wastewater containing mineral and inorganic substances in dissolved and un-

dissolved form. The pre-cooling and subsequent purification of blast-furnace gases requires up

to 20 m3 water per t of pig iron. On its way into the gas cooler the water absorbs fine particles of

ore, iron and coke, which do not easily settle. Gases dissolve in it, especially carbon dioxide and

compounds of the alkali and alkaline earth metals, if they are water-soluble or if they are

dissolved out of the solid substances by gases washed out along with them. In the separation of

coal from dead rock, the normal means of transport and separation is water, which then contains

large amounts of coal and rock particles and is called coal washing water. Coal-washing water is

9

recycled after removal of the coal and rock particles through flotation and sedimentation

processes. Other wastewater from rolling mills contain mineral oil and require additional

installations, such as scum boards and skim-off apparatus, for the retention and removal of

mineral oils. Residues of emulsified oil remaining in the water also need chemical flocculation.

In many cases, wastewater is produced in addition to solid substances and oils, and also contains

extremely harmful solutes. These include blast-furnace gas-washing wastewater containing

cyanide, wastes from the metal processing industry containing acids or alkaline solutions (mostly

containing non-ferrous metals and often cyanide or chromate), and wastewater from eloxal

works and from the waste gas purification of aluminum works, which in both cases contain

fluoride. Small and medium sized non-metallic-minerals plants and metal processing plants are

so situated that they discharge their wastewater into municipal wastewater systems and have to

treat or purify their effluents before discharge, in compliance with local regulations.

B. Organic industrial wastewater:

Organic industrial wastewater contains organic industrial waste flow from those chemical

industries and large-scale chemical works, which mainly use organic substances for chemical

reactions. The effluents contain organic substances having various origins and properties. These

can only be removed by special pretreatment of the wastewater, followed by biological

treatment. Most organic industrial wastewaters are produced by the following industries and

plants:

The factories manufacturing pharmaceuticals, cosmetics, organic dye-stuffs, glue and

adhesives, soaps, synthetic detergents, pesticides and herbicides;

Tanneries and leather factories;

Textile factories;

Cellulose and paper manufacturing plants;

Factories of the oil refining industry;

Brewery and fermentation factories;

In this report we will basically emphasize on Textile Industry effluents.

Textile dyes and other industrial dyes form one of the crucial organic compounds that

cause an increase in environmental dangers. About 1% to 20% of the overall dye productions of

the world is wasted during the dyeing processes, and is released in textile runoff. Thus, there is

an increasing concern for decolorization of dye containing waste water.

10

1.3. TEXTILE INDUSTRY EFFLUENTS:

The textile industry includes a wide range of activities, from preparation of raw material to

pre-treatment, dyeing and finishing of textile material. All these activities consume large amount

of water and are highly polluting. Textile industry processes are known to be intensive users of

water. In Figure I a process diagram of a textile industry is shown, highlighting the steps where

the water consumption and the generation of aqueous effluents occur

Fig I: Different Stages of a textile industry

11

Due to the wide variety of fibers, dyes, process auxiliaries and final products, these processes

generate waters of great diversity and chemical complexity. This complex composition is

reflected in the color, in a high ratio between chemical oxygen demand and biochemical oxygen

demand (COD/BOD5), in the presence of suspended matter and, possibly, heavy metals, and in

variable pH values, mostly in the alkaline range. However, since the fashions are always varying,

the textile effluents composition is never constant. Environmental problems related to the textile

industry are numerous and well documented. Despite the high volume of waste and its high

organic load, the main problem of textile industry effluents is related to the color generated by

unfixed dyes during textile processing and directly released to the effluent. [3]

1.4. TEXTILE DYES :

Since the beginning of times, people have demonstrated the need to add color to all that

surrounds them & wanted to make the world colourful. They use dyes from natural origins, such

as soot, manganese oxide, hematite and ochre for painting their stories in caves, their skins and

their clothes. The textile natural dyes were mainly obtained from plants, insects, fungi and

lichens [4]. Mauveine, the first synthetic dye, was discovered in 1856 by William Henry Perkin.

Since then, thousands of new synthetic dyes have been produced. Nowadays, the total annual

world textile dye production is estimated at about 7x105 tons, with more than 100,000 dyes

available on the market [5]. The largest consumer of these dyes is the textile industry accounting

for around two thirds of its market. To be colored compounds, dyes have to absorb radiation in

the visible range, i.e., 380 to 780 nm. This property is due to the possession of two different

groups, the chromophores, which is typically an electron withdrawing group and is responsible

for the color of the compound, and the auxochrome, which is an electron donating substituent

that can intensify the color of the chromophores and provides solubility and adherence of the dye

to the fiber [6]. Dyes can be divided in 20-30 different groups regarding their chromophores. The

most important are azo (monoazo, diazo, triazo, polyazo), anthraquinone, phthalocyanine and

triarylmethane dyes. Azo dyes represent about 70 % on weight basis of total annual world

production [7]. These dyes are followed, in terms of prevalence, by the anthraquinone dyes.

12

:Different classes of Textile Dyes:

Application class Characteristics

Substrates

Common structures

Acid dyes

Highly water soluble; form ionic interactions

between the -NH3+ groups of fibers and

the negative charge of the

dyes

Wool, polyamide, silk,

nylon, leather

Azo, anthraquinone, triarylmethane

Reactive dyes

Form covalent bonds with -OH, -NH or -SH

groups

Cotton, wool, silk,

nylon Azo, metal

Complex azo, anthraquinone, phthalocyanine

Direct dyes

Their flat shape and length enables them to

maximize van-der-Waals, dipole and hydrogen bonds

Cellulose fibers,

cotton, viscose, paper,

leather, nylon

Sulphonated azo dyes

Basic dyes

Strong ionic interaction between

dye cationic groups and the negative charges

in the copolymer

Synthetic fibers, paper, inks

Azo,

diarylmethane, triarylmethane, anthraquinone

Mordant dyes

Metal salts that act as fixing agent to improve the color

fastness

Wool, leather, silk, modified cellulose

fibers

Azo, oxazine, triarylmethane

Disperse dyes

Non-ionic structure, with polar

functionality, that improves water solubility, van-der- Waals and dipole

forces and the color.

Polyester, polyamide, acetate, acrylic,

plastics

Azo, nitro, anthraquinone, metal complex

azo

13

Pigment dyes

Insoluble, non-ionic compounds or salts

that retain their crystalline particulate

Paints, inks, plastics,

textiles

Azo, metal Complex

phthalocyanine

Vat dyes

Insoluble coloured

dyes which on reduction

dive soluble colourless forms

/leuco form with affinity for the

fiber; can be oxidized back, with H2O2, to

insoluble form

Cellulose fibers, cotton,

viscose, wool

Anthraquinone, indigoid

Ingrain dyes

Insoluble products of a reaction between a coupling component

and a diazotized aromatic amine that occurs in the fiber

Cotton, viscose, cellulose acetate,

polyester

Tetra-azaporphin

Sulphur dyes

Dyeing with sulphur dyes involves reduction and

oxidation processes

Cellulose fibers,

cotton, viscose

Complex polymeric aromatics

Solvent dyes

Non ionic dyes that dissolve the substrate

to which they bind

Plastics, varnish, ink,

waxes, fats

Diazo, triarylmethane, anthraquinone, phthalocyanine

Other dye classes

Food dyes: not used as textile dyes,

nontoxic; Natural dyes: use in

textile processing operations

is very limited; Fluorescent

brighteners: mask the yellowish tint of

natural fibers; Metal complex dyes: strong

complexes of one metal ion

Food, cotton, wool, silk,

polyester, polyamide, soaps and detergents,

paints, plastics

Azo

14

In our study we have used a solution of Reactive Green 19 as industrial wastewater.

Commercial Name: C.I.Reactive Green19

Molecular Structure: Azo Class.

Molecular Formula: C40H23Cl2N15Na6O19S6.

Molecular Weight: 1418.94.

Manufacturing Method: 2,4,6-Trichloro-1,3,5-triazine and 3-Aminobenzenesulfonic acid and

2,5-Diaminobenzenesulfonic acid condensation, Its product (2 moles) and 4-Amino-5

hydroxynaphthalene-2,7-disulfonic acid in acidic and alkaline medium coupling.

Properties and Applications: Blue-green powder, in 20 when solubility of 120 g/L; 50

when solubility of 150 g/L. After dyeing tonal for green, dye bath of copper ions in a red light

and dark (grade 1), encounter iron ion colored light micro to yellow (category 4). The dye sex is

high, the reaction of the medium, and easy to wash the gender is good. For A class of neutral

white, white alkaline for grade C. Apply to cotton, such as glue than small bath dyeing, with high

economic value. Also suitable for polyester/cotton, polyester/stick blended fabric dyeing.

Fig II: Molecular Structure of Reactive green 19

15

1.4.1. ADVERSE EFFECTS OF TEXTILE DYES:

Dyes cause a lot of problems in the environment. The problems which are caused in

environment by dyes are given below:

Depending on exposure time and dye concentration, dyes can have acute and/or chronic

effects on exposed organisms.

The presence of very small quantities of dyes in water (less than 1 mg/L) is highly visible

due to their brilliance.

The greatest environmental concern with dyes is their absorption and reflection of

sunlight entering the water. Light absorption diminishes photosynthetic activity of algae

and seriously influence on the food chain.

Dyes can remain in the environment for an extended period of time, because of high

thermal and photo stability. For instance, the half-life of hydrolyzed Reactive Blue 19 is

about 46 years at pH 7 and 25C.

Many dyes and their breakdown products are carcinogenic, mutagenic and/or toxic to life.

Dyes are mostly introduced into the environment through industrial effluents.

Textile dyes can cause allergies such as contact dermatitis and respiratory diseases,

allergic reaction in eyes, skin irritation, and irritation to mucous membrane and the upper

respiratory tract.

1.5. Different wastewater treatment proceDures Different treatment processes have been found based on the types of wastewater. The process

description of some of the methods is presented below:

Chemical Precipitation: Precipitation of metals is achieved by the addition of

coagulants such as alum, lime, iron salts and other organic polymers. The large amount of

sludge containing toxic compounds produced during the process is the main

disadvantage.

Microfiltration: Ultrafiltration: They are pressure driven membrane operations that use

porous membranes for the removal of heavy metals. The main disadvantage of this

process is the generation of sludge.

16

Nanofiltration: Osmosis: Reverse Osmosis: It is a process in which heavy metals are

separated by a semi-permeable membrane at a pressure greater than osmotic pressure

caused by the dissolved solids in wastewater. The disadvantage of this method is that it is

expensive.

Electrodialysis: In this process, the ionic components (heavy metals) are separated

through the use of semi-permeable ion-selective membranes. Application of an electrical

potential between the two electrodes causes a migration of cations and anions towards

respective electrodes. Because of the alternate spacing of cation and anion permeable

membranes, cells of concentrated and dilute salts are formed. The disadvantage is the

formation of metal hydroxides, which clog the membrane.

Ion-exchange: In this process, metal ions from dilute solutions are exchanged with ions

held by electrostatic forces on the exchange resin. The disadvantages include: high cost

and partial removal of certain ions.

Phyto-remediation: Phyto-remediation is the use of certain plants to clean up soil,

sediment, and water contaminated with metals. The disadvantages include that it takes a

long time for removal of metals and the regeneration of the plant for further bio-sorption

is difficult.

Sorption: Bio-sorption: The search for new technologies involving the removal of toxic

metals from wastewaters has directed attention to bio-sorption, based on metal binding

capacities of various biological materials. Bio-sorption can be defined as the ability of

biological materials to accumulate heavy metals from wastewater through metabolically

mediated or physico-chemical pathways of uptake. Algae, bacteria and fungi and yeasts

have proved to be potential metal bio-sorbents [8]. The major advantages of bio-sorption

over conventional treatment methods include:

i) Low cost; ii) High efficiency; iii) Minimization of chemical and/or biological sludge;

iv) additional nutrient requirement; v) Regeneration of bio-sorbent; and vi) Possibility

of metal recovery.

The bio-sorption process involves a solid phase (sorbent or bio-sorbent; biological

material) and a liquid phase (solvent, normally water) containing a dissolved species to

be sorbed (sorbate, metal ions). Due to higher affinity of the sorbent for the sorbate

species, the later is attracted and bound there by different mechanisms. The process

continues till equilibrium is established between the amount of solid-bound sorbate

species and its portion remaining in the solution.

17

Hence, at present it is very important to remove the pollutants and pathogens from

wastewater to fulfill the needs for irrigation and industrial and domestic use. In the past years,

conventional biological and physical treatment methods (adsorption, Ultrafiltration, coagulation,

etc.) have been used to remove the organic pollutants. These methods are not efficient and cost

effective for wastewaters containing high concentration of more toxic pollutants. This requires

some novel techniques to transfer the highly toxic pollutants chemically into benign species.

Advanced oxidation processes (AOPs) are more efficient, cheap, and eco-friendly in the

degradation of any kind of toxic pollutants. AOPs generate hydroxyl radical, a strong oxidant,

which can completely degrade or mineralize the pollutants non-selectively into harmless

products.

Here in this study we have tried to compare the effects of Adsorption as a low cost

treatment & advanced oxidation process as a highly efficient process on textile wastewater

containing dye and their respective advantages and disadvantages. Modified Tea waste has been

taken as an adsorbent & Sono-Fenton has been used as an AOP & a comparative study has been

done between these two processes.

18

1.6. Adsorption

Adsorption is the adhesion of atoms, ions, or molecules from a gas, liquid, or dissolved

solid to a surface. This process creates a film of the adsorbate on the surface of the adsorbent.

This process differs from absorption, in which a fluid (the adsorbate) permeates or is

dissolved by a liquid or solid (the absorbent). Adsorption is a surface-based process while

absorption involves the whole volume of the material. The term sorption encompasses both

processes, while desorption is the reverse of it. Adsorption is a surface phenomenon. Similar

to surface tension, adsorption is a consequence of surface energy. In a bulk material, all the

bonding requirements (be they ionic covalent, or metallic) of the constituent atoms of the

material are filled by other atoms in the material. However, atoms on the surface of the adsorbent

are not wholly surrounded by other adsorbent atoms and therefore can attract adsorbate. The

exact nature of the bonding depends on the details of the species involved, but the adsorption

process is generally classified as physisorption (characteristics of weak van der Waals forces)

or chemisorptions (characteristic of covalent bonding). It may also occur due to electrostatic

attraction. Adsorption is present in many natural, physical, biological, and chemical systems, and

is widely used in industrial applications such as activated charcoal, capturing and using waste

heat to provide cold water for air conditioning and other process requirements (adsorption

chillers), synthetic resins, increase storage capacity of carbide, and water purification.

Adsorption, ion exchange, and chromatography are sorption processes in which certain adsorbate

are selectively transferred from the fluid phase to the surface of insoluble, rigid particles

suspended in a vessel or packed in a column. Lesser known, are the pharmaceutical industry

applications as a means to prolong neurological exposure to specific drugs or parts thereof The

word "adsorption" was coined in 1881 by German physicist Heinrich Kayser (1853-1940).

1.6.1. Different Popular Adsorbents:

A material that has the ability to extract certain substances from gases, liquids,

or solids by causing them to adhere to its surface without changing the physical properties is

called adsorbent. Carbon, silica, and activated alumina are materials frequently used for this

application. The table below gives clear idea about popular adsorbents and their applications.

19

Adsorbent Applications

Silica Gel Drying of gases, refrigerants, organic solvents, transformer oils

Desiccant in packing and double glazing

Dew point control of natural gas

Activated Alumina Drying of gases, organic solvents, transformer oils

Removal of Hcl from hydrogen

Removal of fluorine in alkylation process

Carbons

Nitrogen from air

Hydrogen from syngas

Ethene from methane and hydrogen

Vinyl chloride monomer (VCM) from air

Removal of odours from gases

Recovery of solvent vapors

Removal of SOX and NOX

Purification of helium

Clean-up of nuclear off-gases

Water purification

Zeolites

Oxygen from air

Drying of gasses

Removing water from azeotropes

Sweetening sour gases and liquids

Purification of hydrogen

Separation of ammonia and hydrogen

Recovery of carbon dioxide

Separation of oxygen and argon

Removal of acetylene, propane and butane from air

Separation of xylenes and ethyl benzene

Separation of normal from branched paraffin

Separation of olefins and aromatics from paraffin

Recovery of carbon monoxide from methane and hydrogen

Drying of refrigerants and organic liquids

Pollution control, including removal of Hg, NOX and SOX

20

Polymers & Resins

Water purification

Recovery and purification of steroids, amino acids

Separation of fatty acids from water and toluene

Separation of aromatics from aliphatic

Recovery of proteins and enzymes

Removal of colors from syrups

Removal of organics from Hydrogen peroxide

Clay

Treatment of edible oils

Removal of organic pigments

Refining of mineral oils

Removal of polychlorinated biphenyls (PCBs)

Selection of an adsorbent basically depends on the following parameters:

Selectivity

Regenerability

Mass transfer kinetics

Compatibility

Cost

In this report we have used Modified Tea waste as a potential, low cost adsorbent for textile

dye removal. It is a natural low cost adsorbent, which is very much effective for textile dye

removal. Many adsorbents are available commercially now-a-days but Tea is basically chosen in

our experiment because it is consumed by most of the people in the world (somewhere between

18 and 20 billion cups of tea are drunk daily on world) and is the second most popular beverage

in the world. So, its very easily available and also it is rich in tannin and polyphenolic

compounds which is very difficult to biodegrade and is an oxygen demanding pollutant. So,

utilization of such waste is very much important

21

Activated Carbon Silica Gel

Modified Tea Waste (Used in this study)

Fig III: Different widely popular Adsorbents

22

1.6.2. Advantages and disadvantages of Adsorption:

Advantages:

Possibility of product recovery

No chemical pollutant control when pollutant (product) recovered and returned to process

Capability of systems for fully automatic, unattended operation

Excellent control and response to process change

Drawbacks:

Product recovery possibly requiring a special, expensive distillation (or extraction)

Adsorbent progressively deteriorating in capacity as the number of cycles increases

Relatively high capital cost (In some cases).

Spent adsorbent may be considered a hazardous waste

Despite being a very cost effective & easily available process, it has a few drawbacks also.

The main problem with this process is the production of a large number of secondary wastes that

cannot be reused after 2 or 3 cycles. Those wastes are very hard to degrade and cannot be

dumped into the environment directly without further treatment. This process is a little bit

laborious and time consuming also. Hence, adsorption process creates another secondary waste

after removing of materials. So, a newer method is in search which will generate lesser

secondary waste and also cost-effective, efficient and less time consuming. To overcome these

drawbacks and provide the necessities Advanced Oxidation Process (AOP) came to light. We

will now shift our focus towards AOP and find out what are the changes required for this process

and the advancement of it and also how this process operates maintaining all the ecological

balance, following the environmental rules and regulations.

23

1.7. AdvAnced OxidAtiOn PrOcess

Advanced Oxidation Process (AOP) in a broad sense, refers to a set of chemical

treatment procedure designed to remove organic (sometimes inorganic) materials in water &

industrial or agriculture or household waste waters by oxidation through reaction with hydroxide

radicals (OH). In real-world it refers more specially to a subset of such chemical processes that

employ O3, H2O2 or UV light. It is particularly useful for cleaning biologically toxic or non

degradable materials such as aromatics, pesticides, petroleum constituents & volatile organic

matters in waste water. Contaminant materials are converted to a large extent into stable

inorganic compounds such as water, CO2 & salts i.e. they undergo mineralization. A goal of

AOP is the reduction of chemical contaminants & the toxicity to such an extent that the cleaned

waste water may be recycled or at least dumped into a conventional sewage treatment.

The AOP (Advanced Oxidation Processes) is usually used for removing contaminants from

waste water coming out of several types of heavy industries like:

Petrochemical & Plastic Industry

Chemical Industry.

Food Processing Industry.

Pharmaceutical Industry.

Metal and Metal Plating Industry.

Textile and Dying Industry

24

Fig IV: Outline of the Advanced Oxidation Process

Fig V: Oxidation potential of different elements

25

1.7.1. Advantages and disadvantages of Adsorption:

Advantages:

Rapid reaction rates.

Small foot print.

Potential to reduce toxicity and possibly complete mineralization of organics treated.

Does not concentrate waste for further treatment with methods such as membranes.

Does not produce materials that require further treatment such as "spent carbon" from

activated carbon absorption.

Does not create sludge as with physical chemical process or biological processes (wasted

biological sludge).

Due to the remarkable reactivity of OH, it virtually reacts with almost every aqueous

pollutants without much discrimination. AOPs could therefore be applicable in many, if

not all, scenarios where many organic contaminants are expected to be removed at the

same time.

Some heavy metals could also be removed in forms of precipitated M(OH) x.

In some AOPs designs, disinfection could also be achieved, leading AOPs to an

integrated solution to some of the water quality problems.

Since the complete reduction product of OH is H2O, AOPs theoretically do not introduce

any new hazardous substances into the water.

Drawbacks:

Capital Intensive.

Complex chemistry must be tailored to specific application.

For some applications quenching of excess peroxide is require

Some treatment requires Pre-treatment of waste water. So it should be employed at the

final stage after primary & secondary treatment.

26

1.7.2. Classification of AOPs:

In this study we have used Sono Fenton as a homogeneous process (Using ultra sound) & in

future work, Photocatalysis as a heterogeneous process (Using TiO2 as catalyst) will be used.

1.7.2.1. Homogeneous Process (Sono Fenton):

In homogeneous Process, the reactants and the catalysts exist in the same phase. The

most commonly used homogeneous process includes ozone and Fenton systems (Fe+ and

Fe+/H2O2). The reactive species is the OH which is used for different purposes. The mechanism

of hydroxyl radical production by ozone can follow two paths:

27

O3 + h O2 + O (1D)

O (1D) + H2O OH + OH

O (1D) + H2O H2O2

H2O2 + h OH + OH

Similarly, the Fenton system produces hydroxyl radicals by the following mechanism:

Fe2+ + H2O2 OH + Fe3+ + OH

Fe3+ + H2O2 Fe2+ + 2OH + H+

Fe2+ + OH Fe3+ + OH

In Fenton type processes, additional sources of OH radicals should be considered: through

sonolysis of H2O2, through reduction of Fe3+ ions under UV light etc:

H2O2 + sonication OH + OH

Fe3+ + H2O + sonication Fe2+ + OH + H+

The efficiency of Fenton type processes is influenced by several operating parameters like

concentration of hydrogen peroxide, pH and concentration of catalyst. These reactions have been

proven more efficient than the other processes but the disadvantages of the process are the low

pH values which are required, since iron precipitates at higher pH values and the fact that iron

has to be removed after treatment.

1.7.2.2. Heterogeneous Process (Photocatalysis with TiO2): [Future Scope]

AOPs are based on the generation of very reactive specieshydroxyl radicals (OH) that

could oxidize wide spectra of organic matter in water quickly and non-selectively. In general,

Photocatalysis can be defined as an acceleration of a photo induced reaction by the presence of a

photo catalyst. In case of heterogeneous Photocatalysis such photocatalysts are solid

semiconductors.

Its mechanism follows the following steps:

Mass transfer of the organic contaminant in the liquid phase to the TiO2 surface.

Adsorption of the organic contaminant onto the photon activated TiO2 surface

Photocatalysis reaction on TiO2

Desorption of intermediate from TiO2

Mass transfer of the intermediate from the interface to the bulk.

28

The mechanism of the photocataytic oxidation under UV light can be presented as follows:

TiO2 + h TiO2 (eCB +hVB+)

TiO2 (hVB+) + H2O TiO2 +H+ +OH

TiO2 (hVB+) + OH TiO2 +OH TiO2 (eCB) + O2 TiO2 +O2

O2 +H+ HO2

HO2 + HO2 H2O2 +O2

TiO2 (eCB) + H2O2 OH + OH

H2O2 +O2 OH + OH +O2

H2O2 + h 2OH

Organic compound + OH degradation products

Organic compound + TiO2 (hVB+) oxidation products

Organic compound + TiO2 (eCB) reduction products

Now to increase the effectiveness hybridization of photo catalysis with membrane process is

used. That is called Photocataytic Membrane Reactor (PMR).

It can be used in two ways:

1. Reactors with catalyst suspended in feed

2. Reactors with catalyst supported in the membrane.

Fig VI: Electron transfer in Advanced Oxidation Process

29

TiO2 over other catalysts:

Attempts have been made to photo catalytically mineralize pollutants (to convert into

CO2 and H2O) in waste water. TiO2 offers great potential as an industrial technology for

detoxification or remediation of wastewater due to several factors:

1. The process uses natural oxygen and sunlight and thus occurs under ambient conditions;

it is wavelength selective and is accelerated by UV light.

2. The photo-catalyst is inexpensive, readily available, non-toxic, chemically and

mechanically stable, and has a high turnover.

3. The formation of photo catalyzed intermediate products; unlike direct photolysis

technique is avoided.

4. Oxidation of the substrates to CO2 is complete.

5. TiO2 can be supported as thin films on suitable reactor substrates.

Thus the study aims to develop an overview of textile wastewater treatment by using a low

cost adsorbent as a conventional treatment procedure and by using Sono Fenton and

Photocatalysis as a newly developed advanced oxidation process.

.

30

CHAPTER 2

LITERATURE REVIEW

31

Adsorption

V.K. Gupta (2009) studied on the application of three low cost adsorbent for dye removal.

It was found that some Low cost adsorbbents, in addition to having wide availability, have fast

kinetics and appreciable adsorption capacities too. Advantages and disadvantages of adsorbents,

favourable conditions for particular adsorbateadsorbent systems, and adsorption capacities of

various low-cost adsorbents and commercial activated carbons as available in this study were

shown. [9]

B.H. Hameed (2009) used spent tea leaves (STL) as a new non-conventional and low-cost

adsorbent for the removal of cationic dye (methylene blue). Batch adsorption experiments were

carried out at 30C. Equilibrium sorption isotherms and kinetics were investigated. The

monolayer adsorption capacity was found to be 300.052 mg/g at 30 C. [10]

N. Nasuha.et.al (2011) showed removal of a basic dye, methylene blue (MB) from

aqueous solution using NaOH-modified rejected tea (N-RT). The results confirmed that the

adsorption isotherm data fitted well by Langmuir isotherm with monolayer adsorption capacity

of 242.11 mg/g. [11]

J. Raffiea Baseri (2012) Activated Carbon (TPAC) of high adsorption capacities and

highly active surface properties were prepared from Thevetia peruviana by physical and

chemical processes such as direct pyrolysis, dolomite process, Chemical activation with H2SO4 +

H2O2, impregnation of raw material with Conc. H2SO4, KOH, ZnCl2 and H3PO4 solution

respectively followed by activation at 800C. Based on the results of the characterization studies,

the activated carbon prepared by impregnation of TPAC with H3PO4 (30%) solution followed by

activation at 800C was selected as a best quality adsorbent due to highest surface area with large

number of pores and low ash content for the removal of dyes from textile industry effluent. [12]

Emine Yagmur.et.al (2012) presents the production of activated carbon from waste tea.

Activated carbons were prepared by phosphoric acid activation with and without microwave

treatment and carbonization of the waste tea under nitrogen atmosphere at various temperatures

and different phosphoric acid/precursor impregnation ratios. The surface properties were

analyzed by SEM, FTIR & BET. The maximum BET surface area was 1157m2/g for the sample

treated with microwave energy and then carbonized at 350 C. In case of application of

32

conventional method, the BET surface area of the resultant material was 928.8 m2/g using the

same precursor and conditions. [13]

Tayyebeh Madrakian.et.al. (2012) adsorption of seven different organic dyes from

aqueous solutions onto magnetite nanoparticles loaded tea waste (MNLTW) was studied.

MNLTW was prepared via a simple method and was fully characterized. The properties of this

magnetic adsorbent were characterized by scanning electron microscopy and X-ray diffraction.

Adsorption characteristics of the MNLTW adsorbent was examined using Janus green,

methylene blue, thionine, crystal violet, Congo red, neutral red and reactive blue 19 as adsorbate.

[14]

Lei Gong.et.al. (2013) showed NaOH-modified dead leaves of plane trees were used as

bio adsorbent to remove methylene blue (MB) from aqueous solution. Variable influencing

factors, including contact time, temperature, initial MB concentration and pH were studied

through single-factor experiments. The results showed that the initial concentration 100 mg/L,

bioadsorbent of 2.5 g/L, pH of 7, room temperature were the best adsorption conditions. The

NaOH-modified bio adsorbent had a high ad-sorption capacity for MB, and its saturated extent

of adsorption was 203.28 mg/g, which was higher than the un-modified dead leaves (145.62

mg/g) and some other bio adsorbents. [15]

Md. Tamez Uddin.et.al (2013) studied the potentiality of tea waste for the adsorptive

removal of methylene blue, a cationic dye, from aqueous solution. Batch kinetics and isotherm

studies were carried out under varying experimental conditions of contact time, initial methylene

blue concentration, adsorbent dosage and pH. The adsorption capacity of methylene blue onto

teawaste was found to be as high as 85.16 mg/g, which were several folds higher than the

adsorption capacity of a number of recently studied in the literature potential adsorbents. [16]

Antonio Zuorro.et.al. (2013) Spent tea leaves (STL), a solid waste that is available in

large amounts worldwide, was investigated as a potential low-cost adsorbent for the removal of

two azo dyes, Reactive Green 19 (RG19) and Reactive Violet 5 (RV5), from contaminated

waters. Preliminary experiments conducted on untreated STL showed that this material exhibited

very low removal efficiencies (

33

to 300 C for 1 hour, removal efficiencies of 98.8 % and 72.8 % were observed, respectively, for

RG19 and RV5. [17]

Ekta Khosla.et.al.(2014) described that the objective of the study was to examine the

potential use of Tea waste and anionic surfactant modified house hold tea waste as a low cost

sorbent for a basic dye removal from simulated textile effluent. The adsorbents were

characterized by XRD, SEM and FTIR techniques. Batch adsorption experiments were carried

out for the removal of Basic Red 12 from aqueous solution using tea waste and surfactant

modified tea waste. [18]

Jian-Zhong Guo.et.al. (2014) utilized Chemically modified bamboo (CMB) was utilized

for removing methylene blue (MB) from aqueous media The adsorbent was characterized by

Fourier transform infrared (FTIR) spectra and elemental analysis, which confirms that carboxyl

groups and diethylenetriamine were successfully introduced into the surface of bamboo. By

variation of the parameters like Temperature, Adsorbent dose, pH etc it was found that the

adsorption of MB in CMB fits Langmuir mode well, and the maximum adsorption capacity of

CMB achieved 606 mg g-1 at 298 K, which is much higher than those obtained from previously

investigated bio adsorbents. [19]

Mohammad Foroughi-Dahr.et.al.(2015) investigated the feasibility of using tea waste as

a low cost adsorbent for the adsorption of an anionic dye ( congo red). They made variation in

pH, adsorbent dosage, dye concentration, temperature etc. They also used vibratory mill treated

tea waste that leads to an increase in the adsorption capacity of tea waste from 32.6 mg/g to

43.48 mg/g. [20]

34

ADVANCED OXIDATION PROCESS

A.H. Mahvi et al (2009) assessed the photocataytic oxidation of reactive orange-16

aqueous solution by UV radiation in presence of TiO2. They investigated the effects of dye initial

concentration, pH, TiO2 loading & effect of anion present on dye degradation. The

mineralization was reported by measuring initial & final COD of the solution. He performed the

photocataytic oxidation using a 2.3-L solution containing a specific concentration of selected

dye. Samples were withdrawn from sample points at certain time intervals & analyzed for

decolorization & degradation. It showed a pseudo-first order decolorization rate of RO-16. He

then determined the pH, TiO2 loading & optimized condition for maximum degradation was

found. [21]

M. Y. Multani.et.al (2010) used ozonization process on reactive green-19. They kept

varying the operating parameters like dye concentration, pH & the time of ozone passing. He

found out that by this process [22]:

Decolorization of RG-19 99.68%

COD removed 82%

Maximum removal efficiency Between pH 10-14

M. T. Sulak.et.al (2010) used cheap and eco-friendly bio adsorbent wheat bran. It was

very much effective for textile dyes like Reactive red 180, reactive blue 5, RO-16, direct red 80

& acid red. The % removal increased with the increased amount of dye & adsorbent. They then

studied the process kinetics and effects of parameters to found out the optimum condition [23].

N. Sharma.et.al (2010) showed that low cost adsorbent obtained from agricultural waste

products was found to be having outstanding removal capabilities. The feasibility of various non-

conventional low cost adsorbents prepared from agricultural waste has been focused in this paper

[24].

35

S. Mozia (2011) presented an overview of the hybrid Photocatalysis membrane process &

their possible application. Now to increase the effectiveness hybridization of photo catalysis with

membrane process is used. That is called Photo-catalytic Membrane Reactor (PMR).

It can be used in two ways:

1. Reactors with catalyst suspended in mode.

2. Reactors with catalyst supported on the surface.

Membrane plays role of a simple barrier for photo-catalyst & of a selective barrier for molecules.

An advantage of PMRs with catalyst in suspension from the discussion was concluded that all

the PMRs with catalyst in suspension allow effective retention of photocatalyst particles [25].

M. N. Chong.et.al (2011) studied the recent R&D progresses of engineered-

photocatalysts, photo reactor systems, and the process optimizations and modeling of the photo

oxidation processes for water treatment. They described how to utilize a multi-variables

optimization approach to determine the optimum operation parameters so as to enhance process

performance and photo oxidation efficiency. They also discussed the effects of different

parameters [26].

S. Ahmed.et.al (2011) also described the influence of parameters on the heterogeneous

photocataytic degradation of pesticides and phenolic contaminants in wastewater. They

described about the different parameters that affect the degradation like [27].

1. Type and composition of the photo catalyst

2. Light intensity

3. Initial substrate concentration

4. Amount of catalyst

5. pH of the reaction medium

6. Ionic compounds in water

7. Solvent types

8. Oxidizing agents

9. Catalyst application mode

10. Calcination temperature

36

D. H. Tseng.et.al (2012) studied the influences of oxygen and hydrogen peroxide (H2O2) on

the degradation and mineralization of monochlorobenzene (MCB) in the UV/TiO2 process. Their

studies provided very useful information that the oxygen was a determining parameter for

promoting the photocataytic degradation [28].

Chih-Huang Weng.et.al. (2013) described decolorization of direct azo dye, direct blue 15

(DB15), by an advanced Fenton process coupled with ultrasonic irradiation (Fenton/US) was

investigated. Zero-valent iron (ZVI) aggregates were used as the catalyst. A positive synergistic

effect occurred when Fentons reagent was combined with ultrasonic irradiation. Experimental

results showed that the optimum conditions for decolorization were pH 3.0, Fe(0) 1 g/L, H2O2

5.15*10-3 mol/L with ultrasound density of 120 W/L at 60 kHz. These conditions yielded 99%

decolorization of DB15 solution within 10 min. [29]

Bing Chen.et.al (2013) investigated the degradation of azo dye direct sky blue 5B by

sonication combined with zero-valent iron (US-FeO) and an evident synergistic effect was

observed. The degradation of direct sky blue 5B followed a pseudo-first-order kinetics &

pseudo-second order kinetics. The degradation rate constants were found to be 0.0206 and 0.169

min_1 respectively. [30]

Hui Zhang (2014) investigated the combination of ultrasound and the advanced Fenton

process (AFP, zero-valent iron and hydrogen peroxide) for the degradation of C.I. Acid Orange

7. The effect of hydrogen peroxide concentration, initial pH, ultrasonic power density, dissolved

gas, and iron powder addition on the decolorization of C.I. Acid Orange 7 was investigated. [31]

Katie Baransi.et.al (2015) investigated the photo catalytic degradation of two phenolic

compounds, p-coumaric acid and caffeic acid, with a suspended mixture of TiO2 and powdered

activated carbon (PAC) (at pH 3.4 and 8). Adsorption, direct photolysis and photocataytic

degradation were studied under different pH and UV light sources (sunlight vs. 365 nm UV

lamps). Photo degradation of anaerobically treated and diluted (1:10) OMW by the combined

TiO2 ePAC sorbent was observed to be higher in terms of the efficiency of polyphenol removal

in comparison to COD removal. A removal of 87% of total polyphenols, compared to 58%

removal of COD, was determined after 24 h exposure to 365 nm UV light (at 7.6Wm-2). [32]

37

CHAPTER 3

AIMS & OBJECTIVES

38

We have found from the forgoing discussions that textile waste water especially

wastewater containing dye is very harmful to the environment. So lots of studies have been done

on degradation and decolorization of textile dye from waste water. It has been found from

literatures that maximum dye concentration that can be emitted is 30 40 ppm. Hence, we have

to degrade the dye to a level that is not harmful to the environment. For that here we have studied

the effects of Adsorption & Advanced Oxidation Process for the decolourization of on textile

wastewater.

Firstly, textile wastewater was simulated. (RG 19 has been treated as textile dye)

Secondly, Modified tea waste was used as adsorbent

Modified Tea Waste was used as a low cost adsorbent. Different experimental runs were

taken by changing various parameters (pH, Adsorbent Dosage, Temperature, RPM etc.).

Then kinetic studies were done. Different adsorption isotherms were taken into account

(Langmuir, Freundlich etc.)

Characteristics studies like SEM, FTIR were done.

Advantages & disadvantages of using adsorbent were discussed.

Thirdly, two kind of Advanced Oxidation Process were taken into account. Homogeneous &

heterogeneous process. Sono fenton was used as a homogeneous AOP in this study &

Photocatalysis using TiO2 will be used as heterogeneous process in future works.

Fourthly, Sono fenton process was used for dye degradation.

Different experimental runs were done varying different parameters e.g. pH, Fe2+ dosage,

H2O2 dosage etc. and optimizing them.

Studies were done based on those data.

Finally, Photo-catalytic oxidation process is done taking TiO2 as catalyst (Future scope of

work)

Different experimental runs will be done in the same process as stated above.

Studies will be done based on those data.

Thus a conclusion was drawn based on the advantages and disadvantages of different processes.

39

Fig VII: Flow chart of the work to be done

Simulated Textile Dye

Adsorption with Modified Tea Waste

Advanced Oxidation Process

Optimization of different process parameters

Different kinetic studies

Different characterization studies

Homogeneous Process

Sono - Fenton

Heterogeneous Process

Photocatalysis [Future Work]

Optimization of different process parameters

Optimization of different process parameters

Different kinetic studies Different kinetic studies

40

CHAPTER 4

Adsorption

41

MATERIALS & METHODS

4.1. Materials:

Reactive Green 19 (molecular weight 1418.94), molecular formula

C40H23Cl2N15Na6O19S6, was procured from Sigma-Aldrich Chemicals. A stock solution of 300

ppm was prepared by mixing with distilled water and was diluted as per requirement. H3PO4,

NaOH and Hcl are of analytical grade, purchased from Mark India Ltd., Mumbai, India and were

used without further purification. Laboratory grade water was prepared with a Sartorious arium

pro VF pure water system. Tea waste was collected from university hostel canteen.

4.2. Preparation of adsorbent:

The tea leaves used in this work were collected from hostel canteen of Jadavpur

University. After that it was washed with boiling water for several times to remove the dirt and

dye particles of tea. Then it was boiled with a 30% H3PO4 solution for modification and the TW

along with the acid solution was kept in a closed place for 24 hours. Then it was washed with

boiling water for several times and was continued till the filtered water was dirt free and

completely color free and till the acid is removed. Treated tea wastes were repeatedly washed with

water until its pH became neutral. It was then oven dried for 48 hours at 80 C. The dried tea waste

was crushed in a mixer grinder & sieved in a screen of mesh 100 micron The prepared sample

was then stored in a plastic container for further use.

4.3. Equipments:

The batch process was conducted in a rotating & time controlling shaker (Sartorius

Certomat). The pH of the different samples was checked by using microprocessor based pH

meter by Hanna Instruments. The samples were centrifuged by a cold centrifuge (Superspin R-

V/F m Plasto crafts). The wet tea waste was dried in a Vacuum oven.

4.4. Analytical Instruments:

The dye concentration was determined by finding out the absorbance at max= 630 nm by

using UV-Vis spectrophotometer (Varian Cary 50).

42

Fig VIII: Time & RPM controlled rotary shaker

Fig IX: UV Spectrophotometer Fig X: Digital pH meter

Fig XI: Cold Centrifuge Fig XII: Vaccum Oven

43

4.5. Methods:

The batch experiments were done taking 100 ml of the dye solution of desired ppm in an

Erlenmeyer flask. pH of the solution was adjusted using NaOH or Hcl. Then requisite amount of

Modified Tea Waste (MTW) was added to the solution and was mixed by the help of vortex.

Then it was placed in a time controlled rotary shaker for 2 hrs. After that the samples were

centrifuged for 10 minutes in a cold centrifuge & then the supernatant fluid was analyzed with

the help of a UV vis Spectrophotometer. The removal of dye was measured by the following

equation: % = ()

100. (1) Where, Co = Initial dye concentration

Ct = Final dye concentration

4.5.1. Effect of Adsorbent dosage:

To study the effect of adsorbent dosage on removal of RG-19, different amounts of MTW

(0.1 1.2 g) were taken and agitated with 100 ml of RG-19 solution of 100ppm. Then the

samples were placed in different Erlenmeyer flasks and were kept in a shaker at 150 rpm for 2 hr

at 30 C without changing the pH. Samples were collected at definite time intervals.

4.5.2. Effect of pH:

pH of the dye solution has a tremendous effect on the dye removal. The effect of pH on

the dye removal was investigated in the range from 2-10. In this study, 100 ml of dye solution of

fixed initial concentration of 100 ppm at varying pH (with the help of acid or base) value was

agitated with 0.8gm of MTW in a thermostatic rotary shaker at a constant speed of 150 rpm for

2hrs at 30 C. The pH was adjusted by adding a few drops of 0.1N of NaOH & 0.1N of Hcl

solutions & was measured using a digital pH meter.

4.5.3. Equilibrium Studies:

Adsorption experiments were carried out by adding a fixed amount of sorbent (0.80 g)

into a number of 250mL stoppered glass Erlenmeyer flasks containing a definite volume (100mL

in each flask) of different initial concentrations (50300 mg/L) of dye solution without changing

the solution pH at temperature of 30 C. The flasks were placed in a time controlled rotary

44

shaker and agitation was provided at 150 rpm for 120 min to ensure equilibrium was reached. At

time t = 0 and equilibrium, the dye concentrations were measured using a double beam UVvis

spectrophotometer at 630 nm wavelength. The amount of adsorption at equilibrium, qe (mg/g),

was calculated by:

= ( ) (/) (2) where Co and Ce (mg/L) are the liquid-phase concentrations of dye at initial and equilibrium,

respectively. V (L) is the volume of the solution and W (g) is the mass of dry sorbent used. The

dye removal percentage can be calculated as follows:

Removal percentage =

100.. (3) where Co and Ce (mg/L) are the liquid-phase concentrations of dye at initial and equilibrium,

respectively.

4.5.4. Batch Kinetic Studies:

The procedures of kinetic experiments were basically identical to those of equilibrium

tests. The aqueous samples were taken at preset time intervals, and the concentrations of dye

were similarly measured. All the kinetic experiments were carried out without pH adjustment.

The amount of sorption at time t, qt (mg/g), was calculated by:

= ( ) (/) (4)

where Ct (mg/L) is the liquid-phase concentration of dye at any time.

4.5.5. Analytical Methods:

The obtained dye solution along with MTW was centrifuged for 10 minutes. The dye

concentrations were measured by measuring absorbance at 630 nm using a double beam UV

spectrophotometer. Prior to the measurement, a calibration curve was obtained by using the

standard RG solution with known concentrations.

45

Results & Discussions

Fig XIII: Decoloration of RG 19 by adsorption at optimum conditions

46

4.6. Effect of pH:

The effect of solution pH on RG19 adsorption was studied using 0.80 g of MTW, 100

mg/L dye initial concentration, pH 210 at 30 C, and the results are shown in Fig. XIV. The dye

adsorption was slightly changed over the pH value from 2 to 8. The dye adsorption was almost

constant at pH 47. The lowest dye adsorption was recorded at pH 3 (15 mg/g). The equilibrium

adsorption (qe) was found to increase with increasing solution pH. The removal % decreased

from 92 to 42% for an increase in pH from 2 to 10. The maximum removal of about 98% was

observed at pH 3. It was observed that, at lower pH (pH3) the adsorption of the dye decreases due to

increase in concentration of OH- ions which bind with the dye, preferably in bulk solution. So the

optimum pH taken is 3.

Fig XIV: Effect of pH on decoloration of RG19 on MTW (Adsorbent dose=0.8g/100mL; temperature = 30C; C0 =100mg/L; stirring rate = 150

rpm)

47

4.7. Effect of Adsorbent dosage:

To investigate the effect of adsorbent dose (g) on dye adsorption, the experiments were

conducted at initial dye concentration of 100 mg/L. Fig XV shows the effect of MTW dose on

the removal of RG 19. It was observed that the removal percentage increased with increase in

adsorbent dose. At equilibrium time, the % removal increased from 42% to 96% for an increase

in MTW dose from 0.1 to 0.8 g. After that, with increment of adsorbent dosage from 0.9 to 1.2g

the % removal remained constant. The increase in % color removal was due to the increase of the

available sorption surface and availability of more adsorption sites. But after 0.8g the solution

had more active sorption surface but no adsorbate was available to be adsorbed. So, optimum

MTW dose was found to be 0.8 g of adsorbent per 100mL of dye solution.

Fig XV: Effect of adsorbent dosage on decoloration of RG19 on MTW (pH= 3; temperature = 30C; C0 =100mg/L; stirring rate = 150 rpm)

48

4.8. Effect of Temperature:

Experiments at different temperatures (25 C, 30 C, 35 C, 40 C) were carried out to study

the effect of temperature on adsorption of RG 19 dye on MTW (fig XVI). It can be seen that the

adsorption capacity increased with the increment of temperature, which indicates that it is an

endothermic process. With increase in temperature the % removal increased at from 92 98%.

But in this study we have taken all the data at room temperature that is 30 C.

Fig XVI: Effect of temperature on decoloration of RG19 on MTW (pH= 3; Adsorbent dose=0.8g/100mL; temperature = 30C; C0 =100mg/L; stirring rate

= 150 rpm)

49

4.9. Effect of stirring speed:

Experiments at different rpm (100 200rpm) were conducted to study the effect of

stirring speed on decoloration of reactive green 19 by MTW adsorbent at optimum conditions. It

is evident from the fig XVII that % removal increases as the stirring speed increases from 100

rpm to 150 rpm, as higher rpm helps more dye to come in contact of the adsorbent. But, as the

rpm increases to more than 150, % removal decreases. Increasing the speed of agitation causes

the thickness of the adsorbent boundary layer to decrease, which lowers the resistance for

transfer of dyes to the surface of the adsorbent owing to the turbulence that would be produced

by high speed. On account of this, the adsorbent molecules are forced towards the surface of the

adsorbent, facilitating the adsorption process. So the optimum stirring speed is taken as 150rpm.

Fig XVII: Effect of stirring speed on decoloration of RG19 on MTW (pH= 3; Adsorbent dose=0.8g/100mL; temperature = 30C; C0 =100mg/L)

50

4.10. Effect of contact time and initial concentration on dye adsorption:

The effect of initial concentration & contact time on the adsorption of RG19 is shown in

Fig XVIII. It can be seen that the amount of dye adsorbed per unit mass of adsorbent increased

with the increase in initial concentration, although % removal decreased with the increase in

initial concentration. The amount of dye adsorbed at equilibrium (qe) increased from 6 to 27.3

mg/g as the initial concentration was increased from 50 to 300 mg/L. The initial concentration

provides an important driving force to overcome all mass transfer resistances of the dye between

the aqueous and solid phases. Hence, a higher initial concentration of dye will enhance the

adsorption process. However, the RG 19 % removals decreased from 98.71% to 72.89% as the

dye concentration was increased from 50 to 300 mg/L. It also shows rapid adsorption of RG 19

in the first 20 min for all initial concentrations, and thereafter, the adsorption rate decreases

gradually till it reaches equilibrium. The equilibrium conditions were reached within 6090 min

for initial concentrations less than 150mg/L while 30 min was needed for concentrations from

200 to 300 mg/L.

Fig XVIII: Effect of contact time and initial concentration on the adsorption

of RG19 on MTW (pH= 3; Adsorbent dose = 0.8g/l; temperature = 30C;

stirring rate = 150 rpm)

51

4.11. Equilibrium studies & Isotherm analysis:

Equilibrium isotherms were used to develop a relation between the equilibrium RG 19

concentration on the adsorbent & in the solution. The equilibrium isotherms in this study were

analyzed using the Langmuir, Freundlich and Temkin isotherms at 30 C.

4.11.1. Langmuir Isotherm:

The Langmuir isotherm model considers a monolayer adsorption, and the adsorbent surface is

considered to be homogeneous. This means that by the adsorption of the 1st molecules of the

adsorbate, the adsorption is restricted on those sites of the adsorbents.

The Langmuir isotherm is represented by the following equation:

=

+ (5)

Where qm (mg/g) and KL (L/mg) are the Langmuir isotherm constants. The equilibrium data were

fitted to Langmuir isotherm and the constants together with the R2 value are listed in Table 1.

Fig XIX: Isotherm analysis for Langmuir model

52

4.11.2. Freundlich Isotherm:

The Freundlich isotherm is an empirical equation assuming that the adsorption process takes

place on heterogeneous surfaces and adsorption capacity is related to the concentration of RG 19

dye at equilibrium:

ln = ln + (ln)(1/) ... (6)

Where kf (mg/g (L/mg) 1/n) is roughly an indicator of the adsorption capacity and 1/n is the

adsorption intensity. The magnitude of the exponent, 1/n, gives an indication of the favorability

of adsorption. Values of n > 1 represent favorable adsorption condition. The values of kf, n and

the linear regression correlation (R2) for Freundlich model are given in Table 1.

Fig XX: Isotherm analysis for Freundlich model

53

4.11.3. Temkin Isotherm:

Temkin considered the effects of some indirect adsorbate/adsorbate interactions on adsorption

isotherms and suggested that because of these interactions the heat of adsorption of all the

molecules in the layer would decrease linearly with coverage.

The Temkin isotherm has been used in the following form:

= () + () (7) where, B = RT/b

The constant B is related to the heat of adsorption. The constants A and B together with the R2

values are shown in Table 1.

Fig XXI: Isotherm analysis for Temkin model

54

Isotherm Parameters: (Table 1)

Langmuir

qm (mg/g) 26.3158

Ka (L/mg) 7.1316

R2 0.988

Freundlich

KF ((mg/g)(L/g)1/n 6.398

R2 0.971

n 3.1645

Temkin

A (L/g) 3.132

B 4.302

R2 0.961

Diagrams show the experimental equilibrium data and the predicted theoretical isotherms

for the adsorption of RG 19 onto MTW. The calculated isotherm constants by non-linear method

are listed in Table 1. It can be seen from Figures that Langmuir isotherm fits the data better than

Freundlich and Temkin isotherms. This is also confirmed by the high value of R2 in case of

Langmuir (0.988) compared to Freundlich (0.971) and Temkin (0.961). This indicates that the

adsorption of RG 19 on MTW takes place as monolayer adsorption on a surface that is

homogenous in adsorption affinity. Table 1 indicates that the computed maximum monolayer

adsorption capacity (qm) of MTW for RG 19 was relatively large, which was 26.31mg/g.

55

4.12. Adsorption kinetics: