Sanjeev R. Shukla

Institute of Chemical Technology, Mumbai | ICT · Department of Fibers and Textile Processing

Life-threatening diseases, especially those caused by pathogens and harmful ultraviolet radiation (UV-R), have triggered increasing demands for comfortable, antimicrobial, and UV-R protective clothing with a long service life. However, developing such textiles with exceptional wash durability is still challenging. Herein, we demonstrate how to fabr...

This study evaluated the effect of biopolishing using cellulase enzymes on the low stress mechanical properties, microstructure, and dye uptake of different cellulosic fabrics (cotton, modal, and cotton denim). The tactile features were studied via the Kawabata evaluation system (KES) and showed increments in tensile elongation, tensile resilience...

In the present work, degumming of Tasar silk was carried out using novel reagents, the ionic liquids (ILs), 1-butyl-3-methylimidazolium chloride [BMIM]Cl and 1-butyl-3-methyl-imidazolium hydrogen sulphate [BMIM]HSO4.The results on weight loss, tensile strength loss and absorbency were compared with soda ash-H2O2 method. These treatments were carrie...

Biosorption potential of oxidised coconut coir (OCC) for removal of Cd(II) was evaluated by multi-column arrangement by connecting three columns in series. Effect of flow rate at 5, 10 and 15 mL/min was studied at 30 mg/L initial Cd(II) concentration. The dynamic capacity of the system was found to be 321, 206 and 83 mg/L for 5, 10 and 15 mL/min fl...

The enzymes are naturally occurring high molecular weight proteins capable of catalysing the chemical reactions of biological processes and hence known as " Bio-catalyst". An enzyme is defined as a protein complex composed of about 200-250 amino acids. The molecular weight of these ferments is very high and is of the order of 10000-100000. they are...

A novel modified admicellar polymerization (ADPM) technique has been proposed for achieving hydrophobicity on cotton fabrics by synthesizing an ultrathin layer of polystyrene on them. The effect of ethanol and methanol on styrene ADPM has been investigated and polymerization time is halved by using methanol at a concentration as low as 0.3 M. Evalu...

This paper reports the development of multi-functional cotton knitted fabric by two-stage process. Cotton knitted fabric was finished with in situ generated nano zinc oxide (nano-ZnO) followed by electrospraying Arkophop FFR a non-fluorocarbon-based hydrophobic chemical. Electrospraying was carried out with different flow rates (0.01 and 0.02 mL/mi...

Decolorization of spent dye baths after dyeing of nylon, silk and wool fabrics with C.I. Acid Red 249 was attempted followed by their reuse in repeated dyeing. The system comprised of a non-sulfur reducing agent, sodium borohydride, along with silver nanoparticles synthesized by plant mediation technique using fresh curry leaves (Murraya koenigii)....

In this study, various pretreatment parameters have been optimized for greige woven modal fabric in an industrial set-up of semi-continuous and continuous pretreatment range in order to overcome its processing issues without altering the inherent fabric softness. Various recipes of pad-batch desizing, pad-steam bleaching and cold causticization hav...

Biosorption potential of oxidized coconut coir (OCC) for removal of Cd(II) from aqueous medium at batch and column level was studied. Lignin and cellulose groups of coir were modified to acidic groups. Optimum biosorption was observed at pH 6. Isotherm data revealed that Langmuir gives best fit for experimental results with maximum adsorption capac...

This article focuses on the development of a durable multi-functional finish for cotton fabric by direct synthesis of nano zinc oxide (nano-ZnO) particles in the pores of the fibres. Anions and cations of zinc nitrate interacted with cellulose molecules and opened up the internal pore structure of cellulosic fibrils that in turn acted as nucleating...

Biodegradation of a cotton-reactive dye (C. I. Reactive Blue 4, 50 mg/L) based on anthraquinone chromophore was attempted by a newly isolated bacterial species, Staphylococcus hominis subsp. hominis DSM 20328. The maximum dye decolorization efficiency was found to be 97% in 24 h upon optimization of pH, temperature, concentrations of carbon source...

The potential of an agro industrial waste Citrus limetta peels (CLP) for biosorption of Ni(II) ions from aqueous solution was explored in batch system in terms of equilibrium, kinetics and thermodynamics. The peels were characterized by FTIR spectroscopy, TGA analysis, and SEM. The effect of process parameters such as initial pH, metal ion concentr...

An ionic liquid, choline hydroxide, was synthesised and used in a mixed alkali system for fixation of homobifunctional reactive dyes. Its molecular structure was confirmed using FTIR, 1H NMR, and 13C NMR spectroscopy. Response surface methodology was employed to optimise the dyeing conditions for reactive dyes using a sodium carbonate–choline hydro...

Pb (II) is extensively used by various industries and the wastewater generated is hazardous to the environment. In the present study, efficiency of a cheap adsorbent in the form of activated carbon, developed from waste biomass for the Pb (II) adsorption is investigated. With BET surface area 1133.25 m2/g and the pore volume 1.41 cm3/g, its adsorpt...

A dyebath containing left-over CI Acid Red 249 after dyeing of wool was completely decolorised using an isolated bacteria Bacillus flexus. Optimisation was carried out by varying the pH, temperature, dye concentration, and microbial loading. Complete decolorisation of a 50 mg l−1 dye solution was achieved in 8 h at pH 7 and 37 °C with 10% v/v loadi...

A commercial model of electronic drapemeter has been developed based on image- analysis technique.

The study is focussed on complete decolorization and degradation of an azo chromophore- based dye CI Reactive Red 195-A (RR 195-A) within 6 h of growth of a newly isolated bacterial species, Staphylococcus hominis subsp. hominis DSM 20328, under optimized conditions of pH 7, temperature 37°C and salt concentration (50 mgL–1). Induction of intracell...

Many dyes applied for textile colouration contain heavy metal ions posing double complexity in possible recycling of such wastewater. The metal containing dyes, color index (C.I.) Acid Red 362 [containing Cr (III)] and Reactive Blue 71 [containing Cu (II)] were first decolourised/degraded by ozonation followed by batch adsorption on activated carbo...

In this work, nano zinc oxide (nano-ZnO) was applied onto cotton fabric by exhaustion method using an ionic liquid (IL), 1-butyl 3-methyl imidazolium chloride [BMIM][Cl], to improve its uptake and fixation. Effect of temperature on the exhaustion of nano-ZnO in the presence of ionic liquid was investigated. A spectrophotometric method was establ...

Activated carbon was prepared from wild almond shells using phosphoric acid as an activating agent. The BET surface area and the pore volume were found to be 1133.25 m2/g and 1.41 cm3/g, respectively. Batch adsorption of two naphthalene dye intermediates, H- and γ-acid was carried out using prepared activated carbon. The maximum adsorption capaciti...

Aminolytic depolymerization of poly (ethylene terephthalate) (PET) bottle waste was carried out by diethanolamine and ethanolamine using synthesized deep eutectic solvents, choline chloride.x ZnCl2 and choline chloride.2 urea, as catalyst. The reaction parameters were optimized through variation in the time of aminolysis, catalyst concentration and...

Two varieties of greige linen fabric were pretreated carefully in an industrial set-up of continuous pretreatment range in order to maintain balance between the desirable properties of superior base white and good absorbency on one hand and the undesirable effects like chemical damage, handle modification and high weight/strength loss on the other....

Polyethylene terephthalate (PET) fibre is largely used in the textile apparel industry. Treatment of PET fibres by sodium hydroxide solution is a well-known process giving smooth surface with decrease in the fibre diameter. Hydrolytic scission of ester linkages of the polyester chains on the fibre surface takes place. Appropriate effects are achiev...

Silk is one of the important textile fibres used in apparel application. Since it is hygroscopic proteinous fibre, it is affected by microbes during usage and storage. Hence, antimicrobial treatment is desired to contain with this problem. Antimicrobial treatment is done using natural and synthetic agents. Nanoparticles have been added as antimicro...

Textile industry is a conventional and pillar industry contributing largely to the national economy. Out of environmental concerns in recent years, special attention is being paid to the application of biotechnology in textile processing industrywiththe advantages of replacement of non-ecofriendly chemicals, milder and safe treatment conditions and...

Oxidative degradation of azo chromophore based C. I. Reactive Blue 171 dye having recalcitrant triazine and naphthalene rings in the structure was attempted using ceric ammonium nitrate (CAN) as an oxidant. The extent of decolorization was evaluated, which was found to be maximum (93.1%) at pH 6.5 and CAN dosage 0.19 mM for 50 mg/L dye solution in...

Silk is hygroscopic and is affected by microorganisms easily. Hence, treatment with antimicrobial agents can facilitate to make silk resistant to microbes. Silver nanoparticles have been attempted by researchers and applied as antimicrobial chemical finish on textiles. Silk has also been applied with silver nanoparticles through exhaust method to o...

In the present investigation, wool fabric was treated with a low-temperature air plasma. The plasma discharge power and treatment time were varied. The effect of plasma treatment on various fabric properties such as wettability, wickability, dyeability, crease recovery angle, breaking strength, and elongation at break was investigated. Surface morp...

Activated carbons (ACs) are prepared from wild almond shells (AS) and coir pith (CP) using phosphoric acid as an activating agent. Various process parameters like acid concentration, impregnation ratio, activation temperature, and time are optimized for better iodine adsorption capacity and yield. The impregnation ratio and the activation temperatu...

High-activity mesoporous carbons were prepared from wild almond shells and coir pith by phosphoric acid activation and applied for adsorption of the dyes, C.I. Reactive Red 2 and C.I. Reactive Yellow 145A. The BET surface areas of these activated carbons were found to be 1133.25 and 1210.58 m2/g, respectively. The equilibrium data were best describ...

Optimization of process parameters for the production of ACs and adsorption isotherms

The application of imidazolium ionic liquids (ILs) as green material for degumming of silk has been investigated. In this study, degumming of eri silk was attempted using ILs 1-butyl-3-methylimidazolium chloride [BMIM]Cl and 1-butyl-3-methylimidazolium hydrogen sulphate [BMIM]HSO4, synthesized in the laboratory. The molecular structures of the ILs...

Degradation of C. I. Reactive Yellow (RY 145), a bi-functional dye containing azo chromophore has been attempted in the presence of potassium persulfate (KPS) as an initiator in the presence of microwave irradiation. The conditions of degradation were optimized and its kinetics was studied. Complete dye degradation was observed in 3600 and 280 s, r...

Biosorption of Cu(II) and Pb(II) ions by alkali-treated coconut coir (ACC) in a continuous fixed-bed column was carried out from their aqueous solutions. ACC was characterized by FTIR and SEM. The effect of process parameters like bed height, flow rate, and influent initial metal ion concentration was examined. The exhaustion time increased with in...

This article is an overview of a novel polymerization technique known as admicellar polymerization (ADPM). ADPM is known as a “surface analogue” of emulsion polymerization, and it consists of three main steps that include (1) admicelle formation, (2) adsolubilization, and (3) polymerization. This review encompasses all the applications of ADPM in t...

This study focuses on the synthesis and application ofdidecanoate of bis(3-hydroxypropyl) terephthalamide(DD-BHPTA) as a secondary plasticizer in poly(vinylchloride) (PVC) compounding. DD-BHPTA was synthe-sized from poly(ethylene terephthalate) bottle wastethrough aminolysis followed by condensation reactionwith decanoic acid. Synthesized DD-BHPTA...

In this report, the degradation of a commercially important dye C. I. Reactive Blue 171 (RB 171) has been investigated using peroxidation under UV light and ozone. The effect of operational conditions such as the dye concentration, operating pH and use of the oxidants such as ozone and UV/H2O2 was studied. Complete decolorization of RB 171 (50 mg/L...

The abundantly available agricultural waste product walnut shells were treated with alkali for enhancement in adsorptive capacity for Cd(II) ions. The raw walnut shells (RWS) and alkali treated walnut shells (AWS) were characterized for functional groups and morphological changes using FTIR and SEM analysis. The adsorption increased drastically bet...

Natural Silk in its native form is made up of the filament fibroin, coated with sericin - gummy matter which is antimicrobial in nature. However, sericin is removed during the pretreatment process. Silk being a natural and hygroscopic, fiber gets attacked by microbes easily. Hence antimicrobial treatment can add value to the wear and care of silk t...

Batch-wise biosorption of Co(II) from aqueous cobalt nitrate solution of different concentrations has been carried out on raw and NaOH-treated lemon peels. They were characterized by Fourier transform infrared spectroscopy, scanning electron microscopy, energy-dispersive X-ray spectroscopy, thermogravimetric analysis and Brunauer-Emmett-Teller surf...

Different varieties of silk differ from each other in their chemical composition as well as the physical, chemical and mechanical properties. Silk degumming is a primary important process, which needs to be carried out uniformly to a sufficient level to get good quality in further processes such as dyeing. In the present study, we have compared the...

The most widely used dyes for coloration of cotton textiles are from reactive class. However, the large amount of unfixed dye causes color in the wastewater, which is environmentally unacceptable. Decolorization of various commercially important reactive dyes in aqueous solutions was attempted by microbial treatment using the bacteria Proteus vulga...

This study focuses on the synthesis and application of dibutyrate of bis(2-hydroxyethyl) terephthalamide (DB-BHETA) as a plasticizer in poly(vinyl chloride) (PVC) compounding. DB-BHETA was synthesized from poly(ethylene terephthalate) bottle waste through aminolysis followed by condensation reaction with butyric acid. Synthesized DB-BHETA was chara...

Disposed off PET bottles were depolymerized via aminolysis using 3-amino-1-propanol in the presence of sodium acetate as a catalyst. The product bis-(3-hydroxy propyl) terephthalamide (BHPTA) was purified and then reacted with ε-caprolactone using dibutyltindilaurate (DBTDL) as a catalyst to get a long chain saturated polyol. Two pack coating syste...

Alkali treated Citrus limetta peels were used for recovery of Ga(III) from its aqueous solution. The raw and alkali treated peels were characterized for functional groups. The efficiency of adsorption increased from 47.62 mg/g for raw peels to 83.33 mg/g for alkali treated peels. Between pH 1 and 3, the adsorption increased and thereafter decrea...

The potential of the biowaste Citrus limetta peels (CLP) was assessed for adsorption of uranium(VI) from uranyl nitrate solution. Maximum adsorption capacity of 75.33 mg g−1 was achieved at pH 4, showing drastic falls thereafter. This was attributed to the presence of UO22+, UO2OH+, (UO2)3(OH)5+ and (UO2)2(OH) 22+ ions. The peels were characterized...

A new, efficient, and inexpensive system has been developed to catalyze Sonogashira cross-coupling reactions between aryl iodides and terminal alkynes. We have employed CuO as well as a novel polymer-supported Cu–N-heterocyclic carbene complex, synthesized using ethanolamine as a ligand, base, and solvent. The reaction conditions were mild and prod...

There is a growing interest in recycling of post‐consumer poly(ethylene terephthalate) (PET) waste for both environmental and economic reasons. PET in the form of disposable soft drink bottle waste was subjected to depolymerization via aminolysis using excess of 3‐amino‐1‐propanol under soxhlet by conventional heating as well as microwave irradiati...

Chemical depolymerization of poly(ethylene terephthalate) (PET) waste is a possible remedy to huge amount of solid waste generation as it results in degradation products that possess a potential of recyclability. PET bottle waste was depolymerized by aminolysis using diethanolamine. Novel synthesis of N1, N1,N4,N4-tetrakis (2-hydroxyethyl) terephth...

A microwave-irradiated, ionic liquid-catalyzed, solvent-free method for the synthesis of triphenylmethane and a phthalein derivative has been developed from different aldehydes or anhydrides and substituted phenols or N,N-diaryl amines, respectively. Short reaction time, ambient reaction conditions, recyclability of catalyst, simple work up and hig...

Aminolytic depolymerization of poly(ethylene terephthalate) (PET) bottle waste with ethanolamine and hydrazine hydrate under atmospheric conditions was investigated in the presence of room temperature ionic liquids. 1‐Hexyl‐3‐methylimidazolium trifluoromethanesulfonate (Hmim.TfO) and 1‐butyl‐3‐methylimidazolium hydrogen sulfate (Bmim.HSO4). (Hmim.T...

Batchwise adsorption of Cu(II), Pb(II), Ni(II) and Fe(II) ions on coconut coir was studied. Coir fiber was subjected to alkali treatment (18% (w/v) NaOH) in order to enhance its metal adsorption capacity and rate of uptake. The maximum metal ion uptake capacity of Cu(II), Pb(II), Ni(II), and Fe(II) on alkali treated coir increased by nearly 3 times...

Aminolytic depolymerization of postconsumer poly(ethylene terephthalate) (PET) bottle waste with 2‐amino‐2‐methyl‐1‐propanol and 1‐amino‐2‐propanol under atmospheric condition was investigated in the presence of catalysts zinc acetate or sodium acetate. The virtual products obtained in pure form were, respectively, bis(1‐hydroxy‐2‐methylpropan‐2‐yl...

Poly (ethylene terephthalate) (PET) is the most popular thermoplastic polymer. The ever‐growing production and utilization of PET has led to postconsumer waste disposal problems because of its nonbiodegradability. The chemical depolymerization of PET waste is a possible remedy, as it results in some recyclable products. The aminolytic depolymerizat...

A series of novel dihydropyrimidin-2(1H)-ones derivatives was synthesized by using Rhizopus Oryzae lipase biocatalyst in deep eutectic solvent. The reaction is characterized by high efficiency and selectivity, short reaction time, mild and environmentally friendly reaction conditions. The yields were found to be significantly higher and reuse of bo...

Recycling of waste PET bottles was attempted using aminolytic depolymerization with hydrazine monohydrate in the presence of NiCl2 and MgCl2 as catalysts, under reflux. The reaction was carried out in a domestic microwave oven of 700 W with suitable modification. Terephthalic dihydrazide (TPDH) was obtained in only 10 min as a pure product with 86...

Uranium is a toxic radioactive element, found in the environment in its hexavalent form. Excessive amounts of Uranium have entered into environment through the activities of nuclear industry. Uranium disposed into the environment can eventually reach the top of the food chain and be ingested by humans, causing severe kidney or liver damage and even...

A simple and efficient Knoevenagel condensation method for the synthesis of trisubstituted electrophilic alkenes was developed using lipase as a biocatalyst. Knoevenagel condensation was performed using the conventional method and using lipases (Aspergillus oryzae or Rhizopus oryzae) as biocatalysts, and reaction time, reaction temperature, yield,...

A series of novel pyrimidinediones and pyrimidinetriones based compounds were synthesized by different techniques such as, with conventional Knoevenagel condensation alone, with a Rhizopus Oryzae lipase biocatalyst and with a deep eutectic solvent (DES). The yield was found to be maximum by using lipase and DES. Reuse of the lipase and DES was poss...

The biomass Citrus limetta fruit peels was subjected to Pb2+ adsorption from aqueous PbNO3 solutions of different concentrations. Pretreatment of the biomass using cold alkali enhanced the adsorption by 87% even after considering the percentage weight loss. The biomass was characterized by scanning electron microscopy (SEM), electrokinetic analysis...

The relative ability of Coriolus versicolor to grow on coir fiber as a ligninocellulosic material was examined. Addition of yeast extract to the culture increased laccase activity, which was further enhanced to the level of 1976 U/L by addition of 1 mM copper sulfate. Laccase thus produced was used without further purification for the decolorizatio...

Terephthalic dihydrazide was obtained through aminolytic depolymerisation of polyester bottle waste by using hydrazine hydrate. It was further reacted with 4-aminobenzoic acid in the presence of polyphosphoric acid to obtain a cyclic compound, 4,4′-[5,5′-(1,4)-phenylene)bis(1,3,4-oxadiazole-5,2-diyl)dianiline, having a heterocyclic moiety. Diazotis...

Glycolytic depolymerization of polyethylene terephthalate (PET) bottle waste was attempted using ethylene glycol (EG) in the presence of chlorides of zinc, lithium, didymium, magnesium, and iron as catalysts. Virtual monomer bis (2-hydroxyethyl terephthalate) (BHET) was obtained in all cases with nearly 74% yield, the highest yield being achieved w...

Abstract Polyethylene terephthalate (PET) fibre waste and disposable soft drink bottle waste were subjected to depolymerization via aminolysis using excess of ethanolamine. The reaction was carried out under non conventional microwave energy in the presence of different simple chemicals as catalysts namely, sodium acetate, sodium bicarbonate and so...

Flocculating agents, widely used In primary effluent treatment, have the advantage of simultaneous removal of the colouring matter while the suspended solids form sludge and become settled. Disperse dyes, used for polyester dyeing, are in the form of an aqueous dispersion In the spent dyebath and hence they may, to advantage, be removed by floccula...

A novel series of 1,4-bis(6-(substituted phenyl)-[1,2,4]-triazolo[3,4-b]-1,3,4-thiadiazoles (5a-b) and 4-bis(substituted phenyl)-4-thiazolidinone derivatives (7a-c) have been synthesized from terephthalic dihydrazide (1) through multistep reaction sequence. 1,4-Bis(5-aryl-1,3,4-oxadiazole-2yl) benzene derivatives (2a-f) and bis-substituted terephth...

The paper aims at effective chemical recycling of poly(ethylene terephthalate) (PET) fiber waste into useful products, such as hydrophobic disperse dyes for synthetic textiles. For this, PET fiber waste was glycolytically depolymerized using excess of ethylene glycol in the presence of sodium sulfate as catalyst. The product, pure bis(2-hydroxyethy...

The potential of coir, a low cost lignocellulosic material, was assessed for the removal of Cu(II) ion from aqueous solutions of copper sulphate. The coir fiber was also modified by an oxidative treatment, whereby the maximum uptake of Cu(II) increased to 6.99 mg/g as compared to 2.54 mg/g for the unmodified coir. A Langmuir type of adsorption was...

Gallium is a strategic material due to its high-tech applications, but its availability in minerals is extremely poor to ensure economically feasible recovery. It is possible through the processing of other Ga-containing minerals, during which Ga gets concentrated. In the present work, Batch-wise adsorption of Ga(III) from the aqueous solution of g...

Abstract Glycolysis of poly (ethylene terephthalate) bottle waste was carried out using microwave energy. A domestic microwave oven of 800W was used with suitable modification for carrying out the reaction under reflux. The catalysts used for the depolymerization in ethylene glycol (EG) were zinc acetate and some simple laboratory chemicals such as...

Silk was dyed with cationic, acid and metal-complex dyes at low temperatures in the presence of ultrasonic energy for relatively short durations. The results in terms of dye uptake were compared with those obtained by conventional processes run at higher temperatures and for longer dyeing times. It was found that the ultrasonic energy helps in obta...

Ultrasound has been used in the dyeing of polyester fibres with disperse dyes at low temperature, and results compared with those achievable in conventional dyeing at the boil using a carrier. Dyeings were enhanced in presence of carrier and by pre-swelling the fibres, although the results obtained were not generally as good as those that can be ob...

Poly(ethylene terephthalate) and poly(butylene terephthalate) filaments were pretreated with different solvents under identical conditions to observe their effect on various properties such as swelling, moisture regain and dyeability. The effect of solvents was found to be more pronounced on the polyethylene than on the polybutylene ester. The resu...

Three different binary mixtures prepared by mixing disperse dyes having close hues were applied to polyester fabric at 4.0% total depth. The compatibility of dyes in these binary mixtures was assessed qualitatively through use of various plots constructed from the differences in the CIELAB colour coordinates δL*, δa*, δb* and δC*ab with respect to...

The kinetics of dyeing acrylic fibres with cationic dyes in the presence of small amounts of the solvents ethylene carbonate, propylene carbonate, nitromethane and iso-amyl alcohol has been studied. The time of half-dyeing was taken as a measure of the rate of dyeing, which was found to decrease with increasing concentration of the solvent in the d...

Polyacrylamide of different molecular masses was found to act as polycationic retarders in dyeing of acrylic fibres with cationic dyes. The method of retardation is simple and economic, having no adverse effect on final dye exhaustion values. The possible mechanisms involved are discussed.

Four different solvents, ethylene carbonate, propylene carbonate, nitromethane and isoamyl alcohol, have been used to study their effect on the glass transition temperature and the swelling of acrylic fibres. Propylene carbonate provided the highest plasticising effect thereby reducing the glass transition temperature. Iso-amyl alcohol showed a pla...

The plasticising solvents ethylene carbonate, propylene carbonate, nitromethane and iso-amyl alcohol have been added to aqueous dyebaths containing disperse and cationic dyes. The dye uptake in all the cases was found to increase linearly with decrease in the glass transition temperature of the acrylic fibres.

Polyester fabric was dyed with a mixture of three disperse dyes of similar hues (all in the red-yellow sector of colour space) in equal proportions at different depths. The colours of the dyed samples were measured on a spectrophotometer attached to an IBM Personal Computer and the results used to study the compatibility of the dyes in mixture. The...

The compatibility of a mixture of disperse dyes in equal proportions having similar hues (all in the red-yellow quadrant of the colour space) has been assessed at different applied depths on polyester fabric, with and without levelling agent, using plots of hue angle against KIS values. The plots were found to be useful in indicating the improvemen...

olyethylene terephthalate (PET) bottle waste was depolymerized using excess of ethylene glycol (EG) in the presence of zeolites, β-zeolite and Y-zeolite as transesterification catalyst. The glycolysis reaction was carried out under reflux in excess of ethylene glycol up to 8 h. The product of glycolysis was mainly the virtual monomer, bis(2-hydroxy...

The addition of a nonionic levelling agent to a dyebath containing a mixture of three disperse dyes in equal proportions and having similar hues (all in the red—yellow sector of colour space) significantly improved their compatibility, especially at higher applied depths of 3.0% and 4.5%. The dyed samples were measured for the differences in their...

As a preliminary study to an investigation of the feasibility of dyeing polyester/cotton blend by an all-in process using a pH-shift method, we have investigated the suitability of three types of conventional reactive dyes by considering the effects of pH and temperature on their hydrolysis and fixation behaviour. Monochlorotriazine, vinyl sulphone...

In this paper, we report zinc perchlorate hexahydrate [Zn(ClO4)2•6H2O] as a highly effective catalyst for the synthesis of 3,4-dihydropyrimidin-2(1H)-ones under solvent-free conditions. These improved reaction conditions allow the preparation of a wide variety of substituted dihydropyrimidinones in high yields and purity under mild reaction conditi...

Formaldehyde has been a topic of concern for every textile industry. Concerns over its use has been raised over the years. Formaldehyde is used as an industrial fungicide, germicide and disinfectant. Formaldehyde is found to be genotoxic, showing properties of both cancer initiator and promoter and can enter the body through ingestion, inhalation a...

Polyethylene terephthalate (PET) waste fibers were initially depolymerized using a glycolysis route in the presence of sodium sulfate as a catalyst, which is a commonly used chemical and ecofriendly as compared to heavy metal catalysts. Good yield of the pure monomer bis(2-hydroxyethylene terephthalate) (BHET) was obtained. Further, to attempt its...

Various decolorization processes can be used for getting the textile wastewater free from color prior to its discharge to the environment or prior to reuse it. In oxidation process, the chromophore is destroyed or converted into biodegradable form. Chemical precipitation/flocculation techniques are used, with varying degree of success, as a tertiar...

Polyethylene terephthalate in the form of waste fibres and disposable soft drink bottles was subjected to depolymerisation through aminolysis using excess of ethanolamine in the presence of different simple chemicals, namely glacial acetic acid, sodium acetate and potassium sulphate, as catalysts. The product bis(2-hydroxy ethylene)terephthalamide...

The depolymerization of nylon 6 was carried out with various solvents, such as formic acid, hydrochloric acid, and sulfuric acid, followed by heating under reflux for different times. From the polymer dissolved and refluxed in formic acid, degradation products with different ranges of molecular weights were collected by fractional precipitation, wi...