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To enhance dye fixation rate in pad-steam dyeing, a preliminary research was carried out to examine that the effect of the water content in water-ethanol mixed medium on reactive dyeing of cotton fabrics. The fabric temperature and dyeing properties as affected by the water content were investigated. Based on the results, a batch procedure was incorporated in the pad-steam dyeing to enhance the interactions between reactive dye and cellulosic fibers. The dyeing properties, chemicals and energy consumption of the pad-batch-steam process and conventional pad-steam process were also evaluated. The results show that reducing the water content could expedite fabric heating and improve dyeing properties significantly. The batching time of 60 min, 20 g/L of sodium carbonate and steaming time of 2.0 min were appropriate for dyeing cotton fabric with 25 g/L of C.I. Reactive Violet 5. Compared with conventional pad-steam dyeing, the color strength and dye fixation rates of dyed fabrics using pad-batch-steam dyeing process were maximum increased by 21.4% and 16.1%, respectively. The proposed dyeing process saved 13.7% dye, 33.3% sodium carbonate, 33.3% steam and 28.5% industrial electricity. The pad-batch-steam dyeing process has significant potential for enhancing dye fixation rate and reducing the dyeing effluent, which is a major step towards cleaner dyeing of cotton fabrics.

High performance cotton fabrics with color, luster and wrinkle resistance are manufactured by three steps. The coloration, wrinkle resistance and luster finishing consume a large number of resources, and generate a huge amount of colored wastewater. The present research reports a cleaner process for dyeing, wrinkle resistance and luster finishing of cotton fabrics. Cotton fabrics were dyed at 35 °C for 15 h with multifunctional reactive dye solutions of high concentrations. Scanning electron microscope images show the fiber cross sections became circular like the mercerized cotton fibers, and the fabrics exhibited nice luster and wrinkle resistant ability. For fabrics with light and middle color, a certain amount of 1,3,5-triacryloyhexahydro-1,3,5-triazine was added into the dye liquor to make the fiber cross section become circular and to make the wrinkle recovery angle reach more than 260° to obtain good wrinkle resistant ability. When the padded fabrics were steamed at 102 °C for 3 min instead of fixing at 35 °C for 15 h, the wrinkle recovery angle also reached 266°. The breaking strength of dyed fabrics decreased with increasing the dye and 1,3,5-triacryloyhexahydro-1,3,5-triazine concentrations. The enhancement of wrinkle resistance of dyed fabrics is due to the crosslink effect of the dye molecules with cellulose macromolecules. This one-step process will save a significant amount of energy and water, and reduce the effluent discharged.

A novel, green and Ecofriendly method for photocatalitic stripping of fixed Reactive Red X-3B dye on cotton substrate was developed at the first time by employing a nano-TiO 2 /UV system in a self-built photoreactor. The effects of photocatalitic stripping parameters such as the initial pH value of working solution, temperature and stripping duration, on color stripping efficiency and fabric tensile strength were investigated. Moreover, the photocatalitic stripping of the fixed reactive dye on cotton substrate in the nano-TiO 2 /UV system was further explored by Attenuated total reflection-Fourier transform infrared spectrometry (ATR-FTIR), X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM). The results show that the fixed Reactive Red X-3B dye on cotton could be photocatalitically stripped or decolorized efficiently by employing the nano-TiO 2 /UV system with a dipped stripping manner in which the substrate was immersed into working solution. The tested stripping parameters of temperature and treatment duration presented notably positive effects on the color stripping efficiency, while an inappropriate control of all the parameters could result in a deterioration of the tensile strength of the substrate. Furthermore, a heterogeneous photocatalitic color stripping mechanism was also supposed for the fixed Reactive dye molecules on cotton substrate in nano-TiO 2 /UV system with the dipped stripping manner.

The dyeing ability of the dichlorotriazine dye on cotton fiber in siloxane media was investigated using a water/oil emulsion system. Compared with traditional water base dyeing, a deeper color depth of fabric and 90% fixation rate of dye could be achieved without using salts in siloxane reverse micro-emulsion system. The hydrolysis mechanism of dichlorotriazine dye, which deeply affects the dyeing performance, was analyzed using high performance liquid chromatography and mass spectrometric methods. In siloxane reverse micro-emulsion dyeing system, the lower hydrolysis of dye is probably due to the grasping water ability of surfactant, the reaction between fiber and dye, and the dye aggregation under a high concentration of dye. Furthermore, the hydrolysis model shows that the hydrolysis rate constants in traditional water base was about three to four times faster than the one in siloxane reverse micro-emulsion system. The dye hydrolysis mechanism in siloxane reverse micro-emulsion system in this study could successfully guide the siloxane reverse micro-emulsion dyeing technology.

Salt-free reactive dyeing is the need of hour in textile reactive dyeing industries to overcome the problems posed by salt usage. A cationic agent (CA) namely 3-chloro-2-hydroxypropyl trimethylammonium chloride was used to cationize the cotton fabric. At present cold pad batch method is used to fix the cationic agent to fabrics. In the present work, exhaust method of application of cationic agent to knitted cotton goods at an industrial level is proposed. The reaction mechanism and effect of materials to liquor ratio, the molar ratio of NaOH to cationic agent, the temperature on dyeing performance are discussed in detail. The cationization process was optimized based on the colour strength of the cationized cotton fabric dyed with the Black GDNN reactive dye at 7% shade which is widely used for knitted fabric processing in India. Various analytical tools such as Fourier transform infrared spectroscopy and field emission electron microscope with energy dispersive X-ray analyser were used to characterize the efficiency of the cationization process. The change occurring in molecular and supermolecular level due to the cationization process is discussed in detail.

Reactive dyes represent the most important class of dyes used in the colouration of cellulose fibre based textiles. Due to a limited degree of dyestuff fixation and competitive hydrolysis of the reactive anchor group in the alkaline dyebath substantial amounts of hydrolysed dyestuff are released at the end of the dyeing process. Assuming a rather high degree of dyestuff fixation with 90%, still 20,000 tonnes of hydrolysed dyestuff are released per year thus forming heavily coloured effluents. A number of techniques have been proposed to treat such waste water streams, e.g. coagulation, precipitation, absorption, chemical destruction and electrochemical decolourisation. A clean alternative presented in this article utilises the direct cathodic reduction of the azo-chromophores, which up to now has been proposed for treatment of concentrated dyestuff solutions. A distinct problem arises from the much low concentrations of reactive dyes in exhausted dyebaths, which has been investigated in this study. As technically relevant representatives three bifunctional reactive dyes Levafix Amber CA, Levafix Fast Red CA and Levafix Blue CA, which can form a trichromy have been studied. The cathodic electron transfer has been analysed with cyclic voltammetry on a hanging mercury drop electrode. Potentiometric titration with Fe(II)-triethanolamine complexes was used to determine the reducing equivalents for complete dyestuff reduction. A multi-cathode electrolyser was applied to study the cathodic dyestuff decolourisation in batch experiments as basis for extrapolation to full scale operation. Successful reductive decolourisation could be obtained for all three investigated dyes. In case of Leavfix Amber CA the original colour recovered some hours after the experiment had been terminated due to air oxidation of the reduced dyestuff. Due to the low dyestuff concentrations present in the dyebath current efficiency was determined with 2.8–8.0% and energy consumption was estimated with of 5.6 kWh/m3 of wastewater to achieve 80% dyestuff decolourisation. The results demonstrate the potential of the technique however also indicate that careful selection of all dyes with regard to their electrochemical behaviour is required for successful implementation of this technology.

The textile dyeing industry has been under the increasing pressure from liberalized economic regime and environmental protection. To alleviate the pressure, nonaqueous dyeing technology has been extensively investigated for improving dye fixation and reducing effluent discharge. In this investigation, a pilot scale dyeing of cotton with high temperature reactive dye Procion Red in silicone oil nonaqueous dyeing system was studied. When the amount of dye is the same, the color depth of dyed cotton fiber and the fixation of dye in the silicone non-aqueous dyeing system are higher than that of the traditional water based dyeing system. When the K/S value of dyed sample is same, silicone and water based dyeing system required initial dye is 2.0% and 4.9% on weight of fiber, respectively. Compared with the traditional water based dyeing, the water consumption and wastewater treatment are only 20% of the traditional water based dyeing system. The higher fixation of reactive dyes not only saves water consumption, but also reduces the consumption of dyes, alkalis and other chemicals by 41%. Moreover, the loss of the silicone nonaqueous medium is controlled within 2%. The hydrolytic reaction energy gap of reactive dye with density functional theory was investigated in silicone nonaqueous medium and traditional water based dyeing system. It was found that the hydrolytic reaction energy of the Procion Red H-E3B in an alkaline environment is much lower than that in a pure aqueous environment. The higher hydrolytic reaction energy of reactive dye in the silicone nonaqueous medium dyeing system proves that why reactive dye can keep a long reactivity during the dyeing. The success of the pilot-scale silicone nonaqueous medium dyeing system shows that this dyeing technology will change the current conventional water dyeing in terms of the huge amount of water consumption and the serious issue of wastewater pollution.

In order to manufacture fabrics, clothing and other textile goods, huge amounts of water are used, generating highly contaminated effluents containing dyes. The focus of this study was the treatment of wastewater containing two textiles dyes (Danix Marinho S-2G 200% - disperse; Remazol Brilliant Blue R - reactive) by electrocoagulation (EC) using aluminum electrodes. The experimental runs were planned using the response surface methodology (RSM) with a Box-Behnken design (BBD) and complete factorial design (CFD). The effects of the operating parameters pH, current intensity (A) and electrolysis time (min) on the percentage of color removal (Rcor %) and operating cost ($/m3) were investigated. Several dyeing processes were also carried out, using polyester or cotton fabric, to evaluate the potential for the reuse of the treated water in the process. The best operating conditions were obtained by applying 4 A and 5 min for the effluent with the dispersed dye and 5–6 A and 30 min for the reactive dye. The influence of the initial pH on the removal of color and reduction in the operational cost of the process was only observed in the case of the effluent containing the reactive dye. The best results were obtained at pH 8. Maximum percentages of color removal of 92.48% and 91.34% and minimum operational costs of $ 0.47 and $ 2.99 were achieved simultaneously, under the optimum operating conditions, for the disperse and reactive dyes, respectively. This study showed that the EC process is an effective wastewater treatment method that is economically competitive. Also, it is a promising alternative for application in the textile industry, particularly since wastewater can be reused in the wash stages of the dyeing process.

Urea plays an important role in the cotton fabric printing process as a dye solubilization and disaggregating agent. However, the using of urea can cause a series of environmental problems because of the high ammonia–nitrogen content in the printing effluent. Polyethylene glycol is a nonionic soluble polymer without nitrogen element. The printability of cotton fabric using polyethylene glycol with different molecular weight, PEG-400, PEG-800, PEG-1000, PEG-2000, as additives instead of urea in the reactive dye print paste was investigated. The intermolecular interaction between the polymer and reactive dye were discussed by the absorbance spectra. The color yield, dye fixation, building up, colorimetric data and fastness of the printed fabrics with polyethylene glycols as additives were evaluated. The results showed that PEG-400, PEG-800, PEG-1000 had better effect on increasing the solubility of the reactive dye. PEG-400 as an additive instead of urea could be applied in urea-free printing for cotton fabric. The printed fabrics can obtain high color yield and fixation, and good fastness properties. PEG-400 and PEG-800 instead of urea have potential application in the cleaner production of the cotton fabric printing. Nowadays, it is urgent to reduce the environmental impacts of textile wet processing.

Textile dyeing uses large amount of freshwater and synthetic dyes. Its effluents have to be subjected to certain treatments to remove the contaminants, especially for residue dyestuffs, before discharging to water bodies for elimination of adverse impacts to the environment. The objective of this research is to fabricate a novel catalyst, carbon aerogel supported copper oxide, and study its catalytic performance for the first time in ozonation of simulated dyeing wastewater for dye degradation. The catalyst was prepared using sol–gel and impregnation method, and characterized by Transmission Electron Microscope and X-Ray Diffraction techniques which suggesting that the nano-sized copper oxide particles successfully embedded and well-dispersed in the amorphous carbon aerogel. The catalytic performance of the catalyst was evaluated by degradation of C.I. Reactive Black 5 in a semi-continuous reactor. The results show that the catalyst has promising potential in ozonation towards dye elimination in dyeing wastewater, in which the dye removal efficiency can be effectively enhanced by the catalyst. In the specific conditions, COD removal could reach 46% in catalytic ozonation system after 60-min reaction, while it was only 29% in ozonation alone without catalyst. In addition, a systematic parameter study was performed to investigate the effect of the temperature, pH, ozone dosage, catalyst amount and dye concentration on dye degradation in terms of color and COD removal.

Contamination of water sources by synthetic dyes is a problem of global concern given their potential toxicities and environmental impacts. A significant increase has been noted in the studies related to developing alternative and efficient systems for the treatment of coloured effluents. This study focused on the development of an environmentally friendly process for the treatment of dye contaminated aqueous media. A natural biosorbent prepared from spent biomass of Pisum sativum was characterized and employed for the removal of a reactive dye for the first time in the literature. Experimental design, modelling and optimization techniques were applied to the batch biosorption process. Process variables were screened using response surface methodology coupled with a Box-Behnken design matrix. Solution pH, biosorbent dosage, reaction time and temperature were considered as key factors. The interactive effects of factor variables on the biosorption, characteristics of the biosorbent and possible dye–biosorbent interactions were discussed. The maximum decolourization yield of biomaterial was 83.2% at an initial concentration of 100 mg L −1 . The best operating conditions were as follows: pH: 2.0, biosorbent amount: 0.6 g (in 25 mL dye solution), reaction time: 56.9 min and temperature 27.3 °C. The Langmuir isotherm model satisfactorily described the equilibrium biosorption data. IR spectra of unloaded and dye-loaded biosorbent indicated the functional groups on the biosorbent, such as a carbonyl that interacted with Reactive Violet 1 dye molecules. SEM micrographs indicated that microprecipitation can also play a role in the decolourization process. This study demonstrates that developed waste biosorbent could be successfully employed as an effective and eco-friendly alternative cleaner to remove reactive dyes from wastewaters.

The increasing contamination of water from textile dyes is one of the major environmental problems facing humanity, which has stimulated extensive investigation of fabricating adsorbents with high removal efficiency and excellent adsorption capacity towards textile dyes. Nature has engineered some intriguing high-performance materials that may be excellent sustainable materials for water purification use. Herein, we report a novel Juncus effusus (JE)-based adsorbent with a three-dimensional network structure and interconnected channels for dye removal from wastewater. To further enhance its adsorption capacity towards textile dyes, the biodegradable chitosan (CS) was employed for the chemical modification of the JE fiber. The results showed that the CS–JE fibers exhibited a high adsorption capacity towards three types of anionic dyes at the temperature of 296 K: 526.3 mg g−1 for C.I. Acid Yellow 11 (AY11), 452.5 mg g−1 for C.I. Reactive Red 195 (RR195), and 255.1 mg g−1 for C.I. Direct Blue 15 (DB15), which outperforms most of the reported CS-modified adsorbents. The Langmuir model satisfactorily fitted the equilibrium adsorption curves of the CS–JE fibers. Throughout the kinetics studies, the adsorption fitted well with the pseudo-second-order model and exhibited a two-stage of intraparticle diffusion, indicating the adsorption of the investigated dyes onto the CS-JE fiber is rather complex that both the external surface adsorption and intraparticle diffusion occurred simultaneously. Finally, taking advantage of the specific 3D network structure and interconnect channels of the CS-JE fiber, a vertically oriented CS–JE cake was fabricated using CS–JE fibers for continuous filtration of dyes from wastewater. The cake exhibited high flow flux and rapid filtration performance under continuous flow without requiring additional pressure. The present work confirmed that the CS-JE composite can be a promising candidate for wastewater treatment.

Heterogeneous photocatalysis, employing semiconductor metal oxides, especially at nano scale is a promising technique to mortify the dye residues from effluent. The photocatalysts on doping with a suitable dopant can be modified to enhance the photocatalytic activity. In this study, undoped and series of Fe3+ doped ZnO have been grown on polyester fabric through low temperature hydrothermal method to generate photocatalytic membrane reactors (PMRs). The material grown on the surface of fabric was characterized by XRD, EDX, SEM, TEM, STEM, AFM, XPS, ICP-MS, DRS and PL studies. For ZnO/PMR and Fe3+@ZnO/PMR photocatalytic activity was determined and examined to increase for Fe3+@ZnO/PMR in the solar region due to the reduction of band gap from 3.2 to 2.6 eV on Fe3+doping. The surface properties of PMRs were also determined by zeta potential and contact angle. The characterized ZnO and Fe3+@ZnO nano discs based PMRs have been used to degrade RB5 reactive dye on irradiating with artificial sunlight (D65, 72 W). The reaction parameters i.e. initial dye and oxidant concentration, pH and irradiation time have been optimized by Response Surface Methodology (RSM). The extent of dye degradation has been evaluated by UV/vis spectroscopy and FTIR. The maximum degradation achieved was 88.89% for ZnO/PMR and 98.34% for Fe3+@ZnO PMR in 180 min. The photocatalytic efficiency of Fe3+@ZnO PMR was investigated for 15 batches, with a slight gradual decrease in activity after eight batches.

Developing a high utilization dyeing approach for cotton fabrics coloring is essential for the textile production in view of economic and ecological reasons. To enhance dye utilization and alleviate environment pollution, an industrializable pre-diffusion technique was applied to traditional pad-steam dyeing to enhance the effective reactions between fibers and reactive dyes. The appropriate dyeing conditions were determined. Dyeing mechanism was revealed by analyzing the speckle rates and reactive dye distribution within the padded fabrics. Dyeing properties, chemicals and energy consumptions, dyeing wastewater absorbance were measured and compared with conventional pad-steam dyeing. The appropriate dyeing conditions were recommended as follows: the padded fabrics were placed at 30 °C for 120 min to complete the pre-diffusion, and then fixed in atmospheric saturated steam for 4 min. The variation of speckle rates verified the change in free water of padded fabrics. Fabric cross-section indicated that the pre-diffusion procedure could improve reactive dye distribution. The recommended technology presented superior dyeing properties including dark color, high dye utilization and satisfactory color fastness. The reduction of about 8% dye, 12.5% Na2CO3 and 20% steam can be achieved using the developed dyeing technology. The absorbance of washing liquor using the recommended process was 0.29, about 65.9% lower than that of conventional pad-steam dyeing. The developed dyeing technology has distinct advantages of high dye utilization and lowly-colored dyeing wastewater discharge, which is conducive to saving chemicals and protecting the environment.

A preventive approach to reduce the environmental burden associated with textile processing was demonstrated by creating a fully recyclable reactive dyeing process for cotton. Reactive dyeing is the most commonly used coloration method for cotton, yet it generates the most problematic effluents that are not only difficult to treat but also non-reusable. Dye hydrolysis, the major barrier to reusing spent reactive dye baths was eliminated in the current study by replacing water with non-nucleophilic green solvents as the processing media. Dye sorption and dye fixation as affected by solvent composition and type of bases were investigated. Compared with conventional aqueous dyeing, the solvent-based process required up to 40% less dye, 97.5% less base, and no inorganic salts. Recycling of all spent baths throughout the process was demonstrated with a 10-cycle repeated dyeing sequence, which displayed consistently high shade build-up and colorfastness. Based on the 10-cycle sequence, the reduction in waste disposal was estimated to be over 99% for both organics and salts. Five different monochlorotriazine dyes featuring different chromophores were successfully applied to cotton using the solvent-based dyeing method. The favorable results implied that discharge-free reactive dyeing could be possible. The solvent dyeing process has significant potential for requiring no modifications of dyes or fabrics and no pressurization. By implementing the principles of reducing waste, reusing, and recycling resources (3Rs), the solvent-based process developed in this study could be a solid step towards sustainable textile processing.

Treatment of dye-containing effluents is a significant challenge because dyes are toxic and pose a threat to the environment. Recent studies have shown that natural clay is able to efficiently remove colour from effluents that contain dyes and various additives. The objective of this study is to investigate the combined effects of dyes, salts and auxiliary chemicals used in the dyeing process, on the adsorption process onto natural clay for the treatment of dye-containing effluents. Batch adsorption experiments were performed using real and synthetic effluents containing dyes (Reactive Red 120, Reactive Orange 84 and Reactive Blue 160), and natural clays (Fouchana and Tabarka). The results show that both of the natural clays are efficient in treating real effluents. Fouchana clay shows a higher efficiency than Tabarka clay in the discolouration of the most colour loaded solution. The added chemical of enzymatic nature (Catalase) facilitates the adsorption of anionic dyes onto clay, likely by electrostatic attraction interaction with the SO 3 - groups in the dye, followed by the adsorption onto the clays, of the dye-enzyme system. The mixture of all additives, enhances the adsorption of dyes on the clays, and does not act as a barrier to the decolouration process. Therefore, clays which are inexpensive and effective adsorbents may be promising alternatives for the treatment of the textile dyeing effluents.

Series of individual preparatory processes prior to dyeing for cotton towel are unavoidable that not only produce a polluted discharge but also require an enormous amount of utilities. We report integration of desizing, bleaching and dyeing processes without discharging each spent bath using enzymes in batchwise method. The desizing effluent discharge eliminated by using Amyloglucosidase–pullanase enzyme to produce glucose; and glucose oxidase (GOx) enzyme (Aspergillus oryzae) to generate hydrogen peroxide (H2O2) that yielded 85 mg/L in the spent bath. In the subsequent bleaching step, conservation of fresh water was also realized. The spent bleached bath was further treated with catalase enzyme to remove residual H2O2 and to carry over the reactive dyeing process. Integrated method showed water saving of 400% and thermal energy saving of 50% in comparison to the conventional method. Moreover, integration of all baths resulted into comparable effluent TDS, Tegewa scale rating, Color International De L'eclairage (CIE) whiteness, absorbency and lower color yield (K/S) without any adverse effect on color fastness of dyed towel. Thus, the integrated method has been shown to have improved eco-sustainability and economy.

Dye baths of low volume compared to the volume of water used in other processing operations generate significant pollution and contaminate other wastewaters that are generally less loaded with pollutants. The aim of the present work is to treat different combination of selected dyeing cycle baths of using the combination of Microfiltration (MF) with Nanofiltration (NF) in order to reuse the treated water in the dyeing process. The characterization of the effluents coming from the different dyeing steps shows that the cotton preparation and dyeing baths are the most polluted due to the presence of dye and to high salinity content. The performances of the combination MF/NF to treat two types of effluents (Effluent 1 which is a mixture of the more polluted baths and effluent 2 which is a mixture of all baths used during the dyeing cycle) were studied. The pretreatment by MF leads to a 50% of pollutant retention except for salts which do not exceed 13%. The addition of NF leads to a high quality of treated effluent with retention of salt, color, suspended matter and COD respectively of 47–52%, 100%, 99.9% and 73–85% depending of the effluent load. The use of MF as a pretreatment prior to NF improves the treatment effectiveness by increasing the operating time and the permeate flux. NF permeate quality was satisfactory enough to be reused in reactive dyeing baths.

Jatropha curcas is a non-edible oil crop predominately used to produce biodiesel. J. curcas pod contains 80% as dried vegetable and remaining 20% are seeds that are used for the biodiesel production in industries. In the present study, J. curcas pods were used for activated carbon preparation and successfully employed as adsorbent for the removal of reactive dye, Remazol Brilliant Blue R (RBBR). Batch adsorption experiments were performed as a function of contact time, pH, adsorbent dosage and initial dye concentration. The experimental results indicate that 0.2 g of activated carbon removed 95% of 50 mg L −1 dye. Adsorption data were modeled using the Langmuir and Freundlich isotherms. Langmuir isotherm was obeyed for the adsorption. Equilibrium parameter value ( R L ) was observed to be in the range of 0–1. The dye adsorption followed the pseudo-first-order kinetics model with regard to the intraparticle diffusion rate. Physico-chemical properties of activated carbon were analyzed by SEM, FTIR and XRD before and after dye adsorption. The adsorbed dye from activated carbon was successfully desorbed (80%) by 1 N NaOH. Bench scale removal of RBBR dye as well as real textile effluent was carried out by J. curcas pods activated carbon (JCPAC). This option will make the agro-industrial waste JCPAC adopted in textile industrial effluent treatment for environmental cleansing.

Micelle dyeing with low liquor ratio is novel fabric dyeing method for cleaner production. Preparation and interaction of dye-surfactant micelles using dibutyl maleic acid ester sodium sulfate surfactant were investigated by UV–Vis spectra. Dyeing properties of cellulose fabrics using micelle dyeing with low liquor ratio were discussed by color yields (K/S), color differences (ΔE), exhaustion (E), fixation (F) and reactivity (R) of three reactive dyes. The results show that reactive dye molecules could be solved in surfactant micelles and form stable dye-surfactant micelles. Micelles formed by dibutyl maleic acid ester sodium sulfate had good anti-agglomeration effect on dye solutions. Liquor ratio of micelle dyeing for cellulose fabrics could be reduced from 1:15 to 1:5. Leveling properties of three reactive dyes using micelle dyeing were good. The exhaustion, fixation and reactivity of all three dyes using micelle dyeing were similar with the conventional dyeing technology. Wet rubbing, washing and perspiration fastnesses of dyed samples using micelle dyeing were also good. Micelle dyeing with low liquor ratio can save a large amount of water and energy.

In this study, nanofiltration membrane and reverse osmosis membrane were tested to investigate the optimal operating conditions for COD, color, salt rejection and permeate flux and evaluate the feasibility of nanofiltration and reverse osmosis membrane combined process to improve the permeate flux and separation efficiencies in reactive dye manufacturing process wastewater. Effects of pressure, types of membrane and dye solution on flux and rejections were investigated. Experiments showed that the type of membrane had a significant effect on both permeate flux and rejection efficiencies. Variations in the applied pressure also affected the COD, color and salt rejections, which increased with increasing pressure. Finally, the nanofiltration and reverse osmosis membrane combined process was found to be suitable for the removal of residual organics, color, salt and the water recycling from waste stream arising from reactive dye manufacturing process. The permeate can be recycled back into the process, thus offering economical benefits by reducing the water consumption and wastewater treatment cost.