STUDY ON CHEMICAL MODIFICATION OF NATURAL AMINOPOLYSACCHARIDE USE AS ABSORBENT TO REMOVE TEXTILE DYES

Contents Introduction 7 CHAPTER 1: OVERVIEW 9 1.1. AMINOPOLYSACCHARIDE 9 1.1.1 Physical properties and structure of aminopolysaccharide 9 1.1.2 Sources of aminopolysaccharide 11 1.1.3 Chemical modification of Aminopolysaccharide. 12 1.1.4 Application of Aminopolysaccharide 14 1.1.5. Chemical modification of Aminopolysaccharide. 14 1.2 Pigments or Dyes 16 1.2.1 Structure of pigments 16 1.2.2 Effect of textile dyes on environment 16 1.2.3 Some methods to remove dyes 17 1.3 Electroplate wastewater treatment 18 1.3.1 Biological method 18 1.3.2 Chemical method. 19 1.3.3 Different physical methods 19 CHAPTER2: EXPERIMENTS 20 2.1 Materials and Apparatus 20 2.2. Extraction of chitin from shrimp crusts 21 2.3. Evaluation of Aminopolysaccharide quality 26 2.3.1. The degree of deacetylation of Aminopolysaccharide 26 2.3.2 Modification of Aminopolysaccharide by ammonium persulfate 27 2.4 Evaluation the absorption ability of APSAMS for dye in wastewater of electric Samsung company 28 2.5 Method for characterization of the components and structure of APSAMS and dye solution 30 CHAPTER3: RESULTS AND DISCUSSION 32 3.1 The result of conversion of chitin from shrimp crust into aminopolysaccharide 32 3.1.1. Infrared Spectroscopy 32 3.2. Ability absorption of Aminopolysaccharide to dyes Error Bookmark not defined. 3.2.1 Effect of pH Error Bookmark not defined. 3.2.2 Effect of time Error Bookmark not defined. 3.2.3 Effect of dye concentration Error Bookmark not defined. 3.2.4 Effect of concentration of Diramen Yellow Error Bookmark not defined. REFERENCES: 35

HANOI UNIVERSITY OF MINING AND GEOLOGY

KIEU NGOC THANH

D P R O G R A

M B A T C

H 3

HANOI UNIVERSITY OF MINING AND GEOLOGY

KIEU NGOC THANH

TABLE CONTENTS

Table 2.1: Effect of ammonium persulfate on crosslinking Table 2.2: Effect of time reaction on crosslinking

Table 2.3: Effect of temperature on crosslinking

Table 2.4: Effect of APS-AMS dose on absorption

Table 2.5: Effect of dye concentration on absorption

Table 2.6: Effect of agitation time on absorption

Table 2.7: Effect of initial pH on absorption

Table 3.1: Efficiency of samples in changing concentration Table 3.2: Efficiency of sample in changing reaction time Table 3.3: Efficiency of samples in changing temperature Table 3.4: The best condition in chemical modification of

aminopolysaccharide

Figure 2.1: Shell shrimp after demineralization process

Figure 2.2: Experiment progressing

Figure 2.3: Shell shrimp after deacetyl process

Figure 2.4: Aminopolysaccharide dissolved in Acetic acid

Figure 2.5: Procedure of synthesis of aminopolysaccharide from shrimp crusts Figure 3.1: IR of Aminopolysaccharide

Figure 3.2: Infrared spectroscopy of 4 samples in changing concentration Figure 3.3: Infrared Spectroscopy of 4 samples in changing time reaction Figure 3.4: Infrared Spectroscopy of 4 samples in changing temperature Figure 3.5: UV-VIS of sample in different pH

Figure 3.6: Investigation of pH

Figure 3.7: UV VIS of sample with different time reaction

Figure 3.8: Investigation of time reaction

Figure 3.9: UV-VIS of samples in different concentration

Figure 3.10: Investigation of dye’s concentration

Figure 3.11: UV-VIS of samples in different concentration

Figure 3.12: Investigation of APS’s concentration

Introduction

Every year, some 6 million to 8 million tonnes of waste crab, shrimpand lobster shells are produced The shell waste produced by the seafoodindustry is a growing problem, with significant environmental and healthhazards Shrimp processing effluents are very high in biological oxygendemand, chemical oxygen demand, total suspended solids, fat-oil-grease,pathogenic and other microflora, organic matters and nutrients

Shrimp processing effluents are, therefore, highly likely to produceadverse effects on the receiving coastal and marine environments Shrimps andlobsters are among the most popular crustaceans For instance, specks of fleshleft in the shells serve as an ideal growth media for pathogenic bacteria Thisleads to the need to burn the shells, an environmentally costly activity giventheir low burning capacity

Chitin is the major component in the shell of the shrimps, and crabs,cartilage of the squid, and outer cover of insects It is also extracted from anumber of other living organisms in the lower plant and animal kingdoms,serving in many functions where reinforcement and strength are required.Aminopolysacharide is a natural polysaccharide comprising of copolymers ofglucosamine and N-acetylglucosamine, and can be obtained by the partialdeacetylation of chitin In its crystalline form, aminopolysaccharide isnormally insoluble in aqueous solutions above pH7; however, in dilute acids(pH6.0), the protonated free amino groups on glucosamine facilitate solubility

of the molecule

Aminopolysaccharide has been widely used in vastly diverse fields,ranging from waste management to food processing, medicine and

CHAPTER 1: OVERVIEW

1.1. A MINOPOLYSACCHARIDE

1.1.1 Physical properties and structure of aminopolysaccharide

Chitin found in the exoskeleton of crustaceans, the cuticles of insects, andthe cells walls of fungi, is the most abundant aminopolysaccharide in natureThis low-cost material is a linear homopolymer composed of b(1-4)-linked N-acetyl glucosamine It is structurally similar to cellulose, but it is anaminopolymer and has acetamide groups at the C-2 positions in place of thehydroxyl groups The presence of these groups is highly advantageous,providing distinctive adsorption functions and conducting modificationreactions The raw polymer is only commercially extracted from marinecrustaceans primarily because a large amount of waste is available as a by-product of food processing Chitin is extracted from crustaceans (shrimps,crabs, squids) by acid treatment to dissolve the calcium carbonate followed byalkaline extraction to dissolve the proteins and by a decolorization step toobtain a colourless product

More important than chitin is its derivative, aminopolysaccharide.Aminopolysaccharide is prepared by deacetylating chitin

Figure 1.1: Commercial Aminopolysaccharide

Physical natural of Aminopolysaccharide

Aminopolysaccharide is also crystalline and shows polymorphismdepending on its physical state Depending on the origin of the polymerand its treatment during extraction from raw resources, the residualcrystallinity may vary considerably

Generally, commercial chit- osans are semi-crystalline polymers,Crystallinity plays an important role in adsorption efficiency.itdemonstrated that decrystallized aminopolysaccharide is much moreeffective in the adsorption of anionic dyes Crystallinity controls polymerhydratation, which in turn deter- mines the accessibility to internal sites.This para- meter strongly influences the kinetics of hydratation andadsorption

Chemical structure of Aminopolysaccharide

Commercial aminopolysaccharide also varies greatly in its MW anddistribu- tion, and therefore its solution behavior The MW ofaminopolysaccharide is a key variable in adsorption properties because itinfluences the polymer’s solubility and viscosity in solution

The degree of N-acetylation (DA) or DD The DD parameter is

essential, though the hydroxyl groups on the polymer may be involved in

attracting dye molecules, the amine functions remain the main activegroups and so can influence the polymer’s performance.

Aminopolysaccharide is the high hydrophilic character of thepolymer due to the large number of hydroxyl groups present on itsbackbone With an increase in DD, the number of amino groups in thepolymer increases, and with an increase of MW, the polymerconfiguration in solution becomes a chain or a ball

1.1.2 Sources of aminopolysaccharide

The potential value of such shells for the chemical industry is being ignored Scientists should work out sustainable ways to refine crustacean shells, and industry should invest in using this abundant and cheap renewable

Protein is good for animal feeds For example, Penaeus shrimp shells

contain all the essential amino acids and have a nutrient value comparable to that of soya-bean meal Today, the protein is not being used because the currentprocessing methods destroy it

Calcium carbonate has extensive applications in the pharmaceutical,

agricultural, construction and paper industries It currently comes mainly fromgeological sources such as marble and limestone These sources are plentifulbut might contain heavy metals that are difficult to remove

Chitin is a linear polymer and the second most abundant natural

biopolymer on Earth (after cellulose) It is found in fungi, plankton and theexoskeletons of insects and crustaceans, and organisms generate about 100billion tonnes of chitin every year Currently, the polymer and its water solublederivative, amonipolysacharide, are used in only a few niche areas ofindustrial chemistry, such as cosmetics, textiles, water treatment andbiomedicine Its potential is much greater

Figure 1.2: Shell Biorefinery

1.1.3 Chemical modification of Aminopolysaccharide.

Crosslinking.

Raw aminopolysaccharide powders also tend to soluble in acidicmedia and therefore cannot be used as an insoluble adsorbent under theseconditions One method to overcome these problems is to transform theraw polymer into a form whose physical characteristics are more attractive

So, crosslinked beads have been developed and proposed

After crosslinking, these materials maintain their properties andoriginal characteristics, particularly their high adsorption capacity,although this chemical modification results in a decrease in the density offree amine groups at the surface of the adsorbent in turn lowering polymerreactivity towards metal ions

They also indicated that the crosslinking ratio slightly affected theequilibrium adsorption capacity for the three cross linkers under the range

The amount of dye adsorbed was found to be higher in acidic than in basicsolution.

The ability of aminopolysaccharide to selectively adsorb dyes could

be further improved by chemical derivatization The presence of newfunctional groups on the surface of beads results in increases in surfacepolarity and the density of adsorption sites, and this improves theadsorption selectivity for the target dye

Aminopolysaccharide Preprotonation

In dilute aqueous acids, the free amino groups are protonated and the

polymer becomes fully soluble below ~pH 5 Since the pKa of the amino

group of glucosamine residues is about 6.3, aminopolysaccharide isextremely positively charged in acidic medium So, treatment ofaminopolysaccharide with acid produces protonated amine groups alongthe chain and this facilitates electrostatic interaction between polymerchains and the negatively charged anionic dyes

In fact, the solubility and its extent depend on the concentration and

on the type of acid The polymer dissolves in hydrochloric acid and organicacids such as formic, acetic, lactic and oxalic acids However, solubilitydecreases with increasing concentrations of acid Solubility is also related

to the DA, the ionic concentration, as well as the conditions of isolationand drying of the polymer

electrochemical sensors for in-situ detection of trace contaminants In sensortechnology, naturally-derived aminopolysaccharide is used primarily as animmobilizing agent that results from its enzyme compatibility, and stabilizingeffect on nanoparticles Contaminant-sensing agents, such as enzymes,microbes and nanoparticles, have been homogeneously immobilized inaminopolysaccharide gels by using coagulating or crosslinking agents.

They have also been applied in permeable reactive barriers to remediatemetals in soil and groundwater Both aminopolysaccharide and modifiedaminopolysaccharide have been used to phytoremediate metals; however, themechanisms by which they assist in mobilizing metals are not yet wellunderstood In addition, microbes have been used in combination withaminopolysaccharide to remediate metals (e.g., Cu and Zn) in contaminatedsoils

1.1.5 Chemical modification of Aminopolysaccharide.

Crosslinking.

Raw aminopolysaccharide powders also tend to soluble in acidicmedia and therefore cannot be used as an insoluble adsorbent under theseconditions One method to overcome these problems is to transform theraw polymer into a form whose physical characteristics are more attractive

So, crosslinked beads have been developed and proposed

After crosslinking, these materials maintain their properties andoriginal characteristics, particularly their high adsorption capacity,although this chemical modification results in a decrease in the density of

free amine groups at the surface of the adsorbent in turn lowering polymerreactivity towards metal ions.

They also indicated that the crosslinking ratio slightly affected theequilibrium adsorption capacity for the three cross linkers under the range.The amount of dye adsorbed was found to be higher in acidic than in basicsolution

The ability of aminopolysaccharide to selectively adsorb dyes could

be further improved by chemical derivatization The presence of newfunctional groups on the surface of beads results in increases in surfacepolarity and the density of adsorption sites, and this improves theadsorption selectivity for the target dye

Aminopolysaccharide Preprotonation

In dilute aqueous acids, the free amino groups are protonated and the

polymer becomes fully soluble below ~pH 5 Since the pKa of the amino

group of glucosamine residues is about 6.3, aminopolysaccharide isextremely positively charged in acidic medium So, treatment ofaminopolysaccharide with acid produces protonated amine groups alongthe chain and this facilitates electrostatic interaction between polymerchains and the negatively charged anionic dyes

n fact, the solubility and its extent depend on the concentration and

on the type of acid The polymer dissolves in hydrochloric acid and organic

A dye or pigments is a coloured compound that can be applied on asubstrate With few exceptions, all synthetic dyes are aromatic organiccompounds There are many structural varieties such as acidic, disperse, basic,azo, diazo, anthraquinone-based and metal complex dyes.

In the field of chemistry, chromophores and auxochromes are the majorcomponent element of dye molecule Dyes contain an unsaturate groupbasically responsible for colour and designated it as chromophore (“chroma”means colour and “phore” means bearer)

Figure 1.3: Examples of pigment in the electroplate industry

1.2.2 Effect of textile dyes on environment

In the electroplate industry, up to 200,000 tons of these dyes are lost toeffluents every year during the dyeing and finishing operations, due to the

inefficiency of the dyeing process Unfortunately, most of these dyes escapeconventional wastewater treatment processes and persist in the environment as

a result of their high stability to light, temperature, water, detergents,chemicals, soap and other parameters such as bleach and perspiration

Electroplate wastewaters are characterized by extreme fluctuations inmany parameters such as chemical oxygen demand (COD), biochemicaloxygen demand (BOD), pH, color and salinity The composition of thewastewater will depend on the different organic-based compounds, chemicalsand dyes used in the dry and wet-processing steps Recalcitrant organic,colored, toxicant, surfactant and chlorinated compounds and salts are the mainpollutants in textile effluents

The effects caused by other pollutants in electroplate wastewater, andthe presence of very small amounts of dyes (<1 mg/L for some dyes) in thewater, which are nevertheless highly visible, seriously affects the aestheticquality and transparency of water bodies such as lakes, rivers and others,leading to damage to the aquatic environment

Some dyes are highly toxic and mutagenic, and also decrease lightpenetration and photosynthetic activity, causing oxygen deficiency and limitingdownstream beneficial uses such as recreation, drinking water and irrigation.One of the most difficult tasks confronted by the wastewater treatment plants

of textile industries is the removal of the color of these compounds, mainlybecause dyes and pigments are designed to resist biodegradation

Considering the fact that the textile dyeing process is recognized as one

of the most environmentally unfriendly industrial processes, it is of extremeimportance to understand the critical points of the dyeing process so as to findalternative, eco-friendly methods

1.2.3 Some methods to remove dyes

Textile materials can be dyed using batch, continuous or semi-continuousprocesses The kind of process used depends on many characteristics including

contaminants thanks to their high oxidative potentials In addition, if the ironand aluminum potential is sufficiently high, other reactions such as directoxidation of organic compounds may take place at the anode.

The electrochemical methods are another way in the textile processes Ingeneral, the electrochemical methods are cleaner than physicochemical andmembrane technologies (the current methods for color removal) because theyuse the electron as unique reagent and they do not produce solid residues.Sodium dithionite (Na2S2O4) is the most used reducing agent in theindustrial dyeing process with this kind of dyes, but after its reaction, it cannot

be recycled It also produces large amounts of sodium sulfate and toxic sulfiteproducts For this reason, the treatment of dyeing effluents requires theaddition of hydrogen peroxide, which also causes high costs and otheradditional problems

1.3 Electroplate wastewater treatment

1.3.1 Biological method

The most economical alternative when compared with other physicaland chemical processes Biodegradation methods such as fungaldecolorization, microbial degradation, adsorption by (living or dead) microbialbiomass and bioremediation systems are commonly applied to the treatment ofindustrial effluents because many microorganisms such as bacteria, yeasts,algae and fungi are able to accumulate and degrade different pollutants