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The textile industry, associated with substantial resource consumption, has posed crucial environmental challenges, mainly in climate change, energy, and water crisis. Considering that cotton is the most manufactured natural fiber and that textile dyeing plays an indispensable role in serving people's demand for fashion and aesthetics, this study conducted an integrated impact-oriented carbon–water–energy (CWE) footprint analysis of dyed cotton fabric production in China from a cradle-to-gate perspective. Results showed that the carbon, energy, and freshwater ecotoxicity footprints of dyeing 1 ton of pure cotton fabrics were 15627.20 kg CO 2 eq, 3405.30 kg oil eq, and 2.01 × 105 PAF·m3·d, respectively. Fiber production, chemical production, and direct emissions were identified as the major contributors to CWE footprints. Cotton straw mulching, advanced dyeing technology, and national power structure optimization were explored to foster sustainable optimization of the cotton-made textile industry. At the conventional wet-processing stage, the dyeing phase had the greatest contribution (56.3%–85.6%) to the environmental impacts from chemicals, followed by pretreatment with a 13.8%–28.3% share. Nonaqueous dyeing routes reduced carbon footprint by 49.1% and water scarcity by 75% compared with water-based dyeing processes, with noticeable increases in noncarcinogen and carcinogen categories. Comprehensive wastewater discharge regulations should be further developed, and the scientific layout between regions along the supply chain from the upstream link to dyeing areas should be strengthened to effectively manage environmental pressures in the textile dyeing industry. • A carbon–water–energy footprint analysis of cotton fabric dyeing is conducted. • Fiber cultivation, chemicals, and direct emissions dominated the footprint. • Heavy metals discharged to water played a 31.8% role on freshwater ecotoxicity. • Sodium sulfate and dyes prevailed in the footprint of chemicals for wet-processing. • Straw utilization and renewable energy utilization yield environmental benefits. [ABSTRACT FROM AUTHOR]

Microalgae are promising and sustainable sources of diverse valuable compounds, including chlorophyll, a pigment widely used in food, feed, and cosmeceutical applications. Exploring its interesting green hue, recent investigations have delved into alternative industrial applications, such as textile dyeing, aiming to minimize reliance on non-sustainable synthetic dyes. To reduce the use of these environmentally harmful compounds in textile dyeing and establish cost-effective and eco-friendly approaches for chlorophyll extraction, this study investigates the use of chlorophyll extracted from Chlorella vulgaris NIVA CHL-108 for wool dyeing. Aqueous biphasic systems (ABS) composed of ethanol and sodium hydroxide were used for chlorophyll extraction, and the chlorophyll-concentrated phase was used for dyeing wool fibers. This sustainable integrated approach allowed complete chlorophyll recovery and enhanced performance for dyeing mordanted and unmordanted wool. The study achieved a remarkable chlorophyll uptake of 87% after two dyeing cycles using unmordanted wool, and a recovery of approximately 98% of copper ions present in the effluents of mordanted wool dyeing process. The study proposes two circular and integrated ABS-based platforms for chlorophyll extraction, concentration, and dyeing, also presenting the challenges impeding their industrial application and proposing strategies to overcome them. This work proves that alcohol/salt ABS-based platforms are simple, circular, and cost-efficient solutions for chlorophyll extraction and utilization in textile dyeing. [Display omitted] • Chlorophyll was effectively extracted from microalgae and applied in wool dyeing. • ABS fully extracted chlorophyll from microalgae, outperforming traditional solvents. • CuSO 4 -mordanted and unmordanted wool presented similar chlorophyll uptakes (≈70 %). • 87 % of all chlorophyll was uptake by unmordanted wool in two dyeing cycles. • Two circular platforms for chlorophyll extraction and wool dyeing were proposed. [ABSTRACT FROM AUTHOR]

The waste management subject is a very important issue today and in the future. Therefore, lots of scholars are endeavoring to investigate the valorization of wastes from different sources, such as paper, metal, glass, and vegetables. In this study, the pistachio soft and hard shells, as an industrial waste material, were used as natural dye sources. For this purpose, waste were collected from Gaziantep province in the south of Türkiye. Then, the soft and hard pistachio shells that had been dried in the shadow were investigated in terms of FTIR analysis and then used as a dyestuff source in the dyeing of cotton fabrics with the help of bio-mordants and metal mordants. Additionally, the antioxidant capacity of the soft and hard shell of pistachio was assessed through the DPPH and FRAP assay methods, and the antibacterial activities were tested against Staphylococcus aureus and Escherichia coli for selected dyed samples. A spectrophotometer was used to determine the CIE L*a*b* color values and (K/S) of cotton fabrics that had been dyed. The results exhibited that the tested wastes could be useful for the coloration of the cotton fabrics, and depending on the used natural dye source, mordanting agent, and mordanting method, the colors were found to have changed, but in general, light brown-ecru-brown colors were observed in the dyed samples. Meanwhile, the fastness of the samples was examined, and the sources were found to exhibit limited light fastness values but good or perfect washing, rubbing, and perspiration fastness. In conclusion, the evaluated conditions were found to be useful for the coloration of cotton, and even more importantly, the pistachio soft and hard shells were observed to reveal great potential for use in textile dye houses as a natural dye source. [ABSTRACT FROM AUTHOR]

In this study, pilot-scale horizontal equipment for zipper tape dyeing in supercritical carbon dioxide (SC-CO 2) was designed and successfully constructed. Two horizontal dyeing autoclaves arranged side by side and a color-matching kettle to accelerate the dye dissolution were the two most appealing characteristics of this equipment. The products dyed under the conditions of a temperature of (90 ± 2) °C, pressure of (23 ± 1) MPa, and time of 50 min, presented an excellent color fastness of staining, drying, and wetting, which were all rated at grades of 4–5. The K/S value of the products dyed in SC-CO 2 was 6.38, while a value of 5.25 was found in water, even the amount of dyes in the SC-CO 2 was lower. The further commercialization of waterless dyeing from pilot-scale studies would have great practical and strategic significance. Image 1 • Waterless dyeing method was introduced in textile industries. • Pilot-scale equipment with two horizontal dyeing autoclaves was designed to overcome the influence of gravity during textile dyeing processing. • Zipper tape was evenly dyed in this equipment in supercritical carbon dioxide. • The promotion of waterless dyeing can reduce energy consumption without paying for effluent contaminations discharge and treatments. [ABSTRACT FROM AUTHOR]

Abstract Textile dyes are xenobiotic contaminants which pose a potential risk on the ecosystem upon their disposal to the water bodies. This study evaluated the efficiencies of different immobilization matrices for its utilization in a reactor with continuous mode operation for decolorization of textile effluent. An effective consortium of bacteria (Brevibacillus laterosporus) and yeast (Galactomyces geotrichum) were immobilized in different support matrices including calcium alginate, polyvinyl alcohol, stainless steel sponge and polyurethane foam to investigate the decolorization of a model azo dye, Remazol red and textile industry effluent. The microbial consortia immobilized in stainless steel sponge and polyurethane foam exhibited 100% decolorization of 50 mg L−1 Remazol red in 11 and 15 h, respectively; however, calcium alginate and polyvinyl alcohol required considerably more time (20 and 24 h, respectively) for complete decolorization. Among all the matrices, The calcium alginate, stainless steel sponge and polyurethane foam showed >95% decolorization of textile industry effluent within 48 h. The calcium alginate and polyvinyl alcohol exhibited stable performance of decolorization with its repeated use for 5 cycles with >76% decolorization. An upflow fixed bed reactor (total volume- 215 mL) packed with the immobilized cells of consortium onto stainless steel sponge attained ∼90% decolorization of textile industry effluent in continuous operation at 10 mL h−1. The decolorization efficiency of the reactor was well maintained (>90%) when the reactor was used repeatedly for three cycles. The overall results indicated that immobilized mixed consortium cells can be considered as an effective tool for its potential application in removal of xenobiotic textile dyes from the textile industry wastewater with >90% of decolorization efficiency. Highlights • Effective microbial consortium was immobilized in different support matrices. • SS-sponge immobilized cells showed 100% decolorization of Remazol red in 11 h. • Calcium alginate, polyvinyl alcohol showed stable decolorization of textile effluent. • The upflow fixed bed reactor can be used for continuous decolorization of effluent. [ABSTRACT FROM AUTHOR]

Abstract Implementing forward osmosis (FO) into textile wastewater treatment process can provide high value to an industry segment which is a large consumer of fresh water and one of the biggest polluters. In this study real textile wastewater was used as feed solution with 1M NaCl, 1M MgCl 2 , blue dye mixture, and green dye mixture as draw solution in FO. Pre-determined concentrations of green and blue dye mixtures based on final desired concentrations (for further use in dyeing process), gave comparable water flux with 1M NaCl and 1M MgCl 2 , however, slightly higher reverse salt flux values were obtained with dyes compared to the inorganic salts. Long-term filtration followed by chemical cleaning of the FO membranes tested resulted in 100% flux recovery with negligible irreversible fouling. Membrane surface characterisation (zeta potential, contact angle, SEM and ATR-FTIR) confirmed efficient FO membrane cleaning and complete flux recovery. Rejection performance of the FO membranes for COD rejection was >94% with up to 55% water recovery. The rejection of TDS, TSS, Zn2+, and SO 4 2− were all >99%. Using the obtained results an OPEX/CAPEX analysis demonstrated the economic feasibility of using the FO process in textile wastewater treatment system. [ABSTRACT FROM AUTHOR]

Abstract Laccase from Myceliophthora thermophila was used to catalyze the polymerization of catechol under high-pressure homogenization for the green coloration of textile substrates. The oxidation reactions were conducted using different forms of laccase, namely native laccase, PEGylated laccase and PEGylated laccase immobilized onto an epoxy resin. The three enzyme forms were deposited inside a polyester fabric bag during the experiments. The amount of polymer obtained was similar when using the three enzyme forms and its dispersion in water/DMSO mixture lead to powder particles of about 30–60 nm. The immobilized and PEGylated enzymes lead to poly(catechol) with 13 and 10 units, respectively, while the native form gave rise to shorter polymers (DP = 8). We have shown that the oxidation of catechol conducted under high-pressure homogenization can be an efficient methodology for the in situ coloration of textiles. The polymers produced by this methodology stained strongly the textile container, revealing this experimental set-up as a promising greener coloration/coating methodology involving milder conditions than the normally used in textile processes. Graphical abstract Image 1 Highlights • Laccase-assisted polymerization of catechol by high-pressure homogenization. • Polyethylene terephthalate (PET) bag as enzyme container. • Green coloration of PET fabric with enzymatically produced poly(catechol). [ABSTRACT FROM AUTHOR]

Abstract Nowadays, clothes dyed with synthetic dyes contain a large variety of harmful products for health and environment. These substances are potentially carcinogenic, especially when they mix with sweat. That is why great efforts were carried out to promote natural dyeing while valuing plants considered as a waste. In this study, aqueous solution extracted from date pits powder is characterized and valorized. Experiments were carried out using Taguchi experimental design to be able to analyze the main effects of each parameter and to deduce optimum conditions for extraction process. Obtained results indicate that the most suitable solvent is acetone with an optimal percentage of 10% of the volume of the solution used fort extraction, the optimal temperature is found at 80 °C and the optimal duration is 90 min. After the extraction under optimum conditions, the stability and the storage conditions of the extracted solution were evaluated using the factorial experimental design. The parameters analyzed are those influencing the dyeing process, namely: the pH of the solution, the temperature and the duration. The analyzed responses are the polyphenol content and the absorbance of the aqueous extract. Obtained results proved that the extracted solution can be conserved in the darkness more than 15 days in 3 °C. Highlights • Solution extracted from date pits is characterized and valorized as a natural dye. • Optimization of extraction process is carried out using Taguchi experimental design. • The extracted solution presented good potential as a dye matter for cotton fibers. • The stability and the storage conditions of the extracted solution were evaluated. [ABSTRACT FROM AUTHOR]

Generally the exhaust dyeing process utilizes a large amount of energy, time and high liquor ratio. On the contrary, the microwave irradiation can be used for the exhaust dyeing that consumes less energy and less time. In this research, the environmental friendly technique, the microwave irradiation, is used to dye cotton fabric at lower liquor ratio through the exhaust dyeing process and it is compared with the conventional dyeing method. The exhaustion percentage, fixation percentage, and color strength values have been measured and a suitable recipe is obtained. It is found that the microwave technique facilitates the process by minimizing the dyeing time and maximizing the exhaustion percentage, fixation percentage, and color strength values. Furthermore, the microwave technique is considered as a green technique and higher exhaustion and fixation percentages indicate that there is comparatively less residue dye in the effluent. XRD and SEM tests also performed to analyze whether the microwave has affected the morphological structure but from the results, there is not a considerable difference observed. Finally, the colorfastness tests have been carried out and compared with the conventionally dyed samples and the results are almost the same for both techniques. Hence the microwave technique is providing almost the same quality product by using less time with the environment friendliness. [ABSTRACT FROM AUTHOR]

A reducing agent is used in indigo dyeing to convert an indigo pigment to a water-soluble leuco form prior to its application on cellulosic fibers. Sodium dithionite (Na 2 S 2 O 4 ), the most widely used reducing agent for industrial indigo dyeing, is considered environmentally unfavorable because sulfite and sulfate generated in the dyebath can cause various problems when discharged into wastewater. In this work, monosaccharides (glucose, fructose and galactose) and reducing disaccharides (lactose and maltose) were investigated as green reducing agents in order to be a substitute for Na 2 S 2 O 4 in the technical indigo dyeing. The redox potential measurement coupled with photometric studies revealed that reducing sugars could be applied in the alkaline reduction of indigo at an elevated temperature. Within 10 min of adding reducing sugars, the redox potentials of the indigo dyebaths were lower than −700 mV and remained nearly constant for an hour. The dyebaths with use of sodium hydroxide led to greater color strength compared to experiments with use of calcium hydroxide. Replacing Na 2 S 2 O 4 with reducing sugars in the technical scale denim production was found to be possible in the preparation of the stock vat. This can lead to substantial reduction in Na 2 S 2 O 4 consumption. [ABSTRACT FROM AUTHOR]

Biomass pigments were considered as prospective alternatives to conventional synthetic dyestuffs. In this paper, biocolorants were prepared from tea polyphenols (TP) and were applied in dyeing. Crude enzyme generated by Aspergillus niger was employed to convert tea polyphenols as precursor into pigments via bioconversion, and simultaneously the dyeing of fabrics was achieved in this process. This work demonstrated that pigments prepared were able to dye fabrics with admirable color fastness and meet application requirements. The bio-pigments can be obtained from low-cost reproducible natural resource, tea stalk, which is a kind of tea residual waste. Dyeing with biomass pigments based on bioconversion was presented in this research in which no environmentally hazardous additive was employed to improve dye-uptake and fixation. Therefore, this innovative dyeing technology is a cleaner production method and the dyed fabrics can be categorized as ecological textiles. [ABSTRACT FROM AUTHOR]

The efficacy of a photo-assisted electrochemical oxidation for the mineralization of real textile effluents (wash water and dye-bath effluent) was investigated by employing a non-photoactive dimensionally stable anode in a tubular flow cell. Under optimized conditions, the photo-assisted electrochemical oxidation was performed at a pH of 2, with a chloride concentration of 2 g L −1 , a current density of 10 mA cm −2 , and a flow rate of 50 mL min −1 . The process efficiency was assessed through ultraviolet–visible spectroscopy, high performance liquid chromatography, Fourier transform-Infra red spectroscopy, nuclear magnetic resonance spectroscopy, chemical oxygen demand and total organic carbon analyses. The results obtained have shown that, in case of wash water effluent, 96% of chemical oxygen demand and 68% of total organic carbon were removed in 180 min of photo-assisted electrochemical oxidation, whereas a simple electrochemical oxidation removed only 70% of chemical oxygen demand and 27% of total organic carbon, in the same time. The energy consumptions were about to 29.8 and 39.5 Wh g −1 of chemical oxygen demand in photo-assisted electrochemical oxidation and electrochemical oxidation. The higher efficiency of photo-assisted electrochemical oxidation is attributed to the formation of oxychloride radicals at acidic pH, as confirmed by electron paramagnetic resonance analysis. The analytical results revealed that the degradation mechanism of photo-assisted electrochemical oxidation is entirely different from that of electrochemical oxidation; in particular, the byproducts formed in the photo-assisted process are free from chlorinated organic compounds and exhibit zero toxicity towards Lemna minor . The photo-assisted electrochemical oxidation proved to be effective also in the case of dye bath effluents with a high organic load: about 90% of the chemical oxygen demand was removed within 5 h at 10 mA cm −1 . The recovered salts from the color-free dye-bath effluent were recycled for further dyeing purposes. [ABSTRACT FROM AUTHOR]

Poly(lactic) acid as a biodegradable polymer has attracted a lot of attentions due to its environmental merits and availability in sufficient quantities for use in the packaging industry. Recycling of poly(lactic) acid and converting it to a new product, instead of a compost material or primary monomer, is an economical and environmental solution. In this paper, recycled poly(lactic) acid fibers melt-spun from disposable package flakes were dyed by using three disperse dyes having different molecular weights and their dyeing behavior and fastness properties have been studied. Dyeing temperature, time and concentration were fully investigated. The results showed that with an increase in the temperature from 80 °C to 120 °C, the amount of dyeing exhaustion rate increased for different disperse dyes. The recycled poly(lactic) acid fibers exhibited a good exhaustion rate in a short time (20 min), low concentrations (0.5% on weight of the fabric) and low temperature (80 °C). The good to excellent washing fastnesses between 4 and 5 were observed for the recycled poly(lactic) acid fibers which were dyed by the three selected disperse dyes under the optimized conditions. Accordingly, it could be considered that the recycled poly(lactic) acid fibers have a great capability to be dyed with low damage, energy consumption, costs and effluent with disperse dyes. [ABSTRACT FROM AUTHOR]

Cleaner production in the textile industry may be realized by replacing certain synthetic substances with natural materials, especially those that are industrial by-products, which offer the added benefit of increasing the value of the textiles. Since natural materials generally pose a low risk to both the human health and the environment owing to their biodegradability, the wastewater released from their manufacturing processes is less polluting, and therefore, it requires less resources and energy for treatment compared to wastewater loaded with synthetic substances. Herein, we report the use of a protein by-product recovered from the oil extraction process of Antarctic krill ( Euphausia superba ) to replace traditional mordanting agents in the dyeing of cotton with tannin-rich natural dye extracted from the bark of Xylocarpus granatum . Antarctic krill protein pretreatment successfully improved the dyeability of the fabrics through the formation of insoluble complexes between the protein and tannin. The color parameters of the dyed samples were measured based on the CIE L*a*b* system. The obtained reddish-brown fabrics exhibited mostly good to excellent color fastness ratings in response to washing and other wet treatments. They also displayed durable UV protection properties, with the UPF rating reaching the maximum (50+) level, despite being washed for 50 cycles. Both the Antarctic krill protein and tannin contributed to improved UV protection efficiency due to the presence of UV-absorbing moieties and slight changes in the resulting fabric thickness and cover factor. [ABSTRACT FROM AUTHOR]

Textile grade dye was extracted from roasted peanut skin ( Arachais hypogaea ) through aqueous extraction. The dye was characterised by phyto-chemical, uv visible spectroscopy and FTIR analysis. Cotton, silk and wool fabrics were dyed at different temperatures as well as using microwave energy without using any mordants. Dyed fabrics were assessed for their colour values, fastness properties and ultraviolet protection factor. All the fabrics shown good affinity for the dye. Uniform dyeing was observed in all fabrics; however, the dye exhaustion was higher in silk and wool than cotton. The dyed fabrics possessed good to very good fastness properties with and an ultraviolet protection factor up to 65. A comparative evaluation of synthetic dyes required to produce the same shade with that of peanut skin dye was also performed. [ABSTRACT FROM AUTHOR]

Benzidine is used as an intermediate compound for the production of many types of dyes and it is found to be carcinogenic to human. The use of benzidine dyes are significantly withdrawn in most of the industries, but still it is used as colorant to dye the fabrics. The present study focuses on the treatment efficiency of electrochemical process in the removal of benzidine based triazo dye namely C.I. Direct Green 1 (DG1). Various key process parameters are employed to analyses the efficiency of ferrous and aluminum hydroxides on removal of colour is observed as 99.10%, chemical oxygen demand (COD) of dye solution observed as 75.71 and 89.65% for stainless steel (SS) and aluminum (Al) electrodes. The process efficiency is analyzed by observing the variation of pseudo first order kinetic rate constant values of 0.115 and 0.256 min −1 , energy and electrode consumptions are found as 1.50 kWh/kg dye, 0.75 kWh/kg dye and 0.31 kg Fe/kg, 0.06 kg Al/kg dye for SS and Al electrodes respectively. The dye removal mechanism with metal hydroxides is observed as the partial degradation of azo bonds and followed by sweep coagulation with iron hydroxides/oxyhydroxides and charge neutralization with aluminum hydroxides/oxyhydroxides are supported by UV–visible, Fourier Transform Infrared (FTIR) and Scanning Electron Microscope and Energy Dispersive X-Ray (SEM-EDX) spectroscopy analysis of treated water and electrocoagulated flocs. Finally, the cost of electrocoagulation is evaluated for treatment of DG1 and it is identified to be 1.89$/kg dye for SS electrodes and 0.78$/kg dye for Al electrodes. [ABSTRACT FROM AUTHOR]

Denim fabric waste was used as a carbon precursor, and chemically activated with phosphoric acid in the ratio of 1:1 ( v:m ) under a slow pyrolysis process to obtain activated carbon fibers (ACFs). The chemical and physical properties of the ACFs were investigated from the thermogravimetric analysis (TGA), N 2 porosimetry, scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray diffraction (XRD), Raman and Fourier transform infrared spectroscopy (FTIR), Boehm titration method, and point of zero charge ( pH PZC ). The obtained ACFs showed high yield (53%), BET surface area of 1582 m 2 g −1 , mesoporous features (average pore diameter of 3.60 nm), and surface acidic properties ( pH PZC value of 2.13 and 1.13 mmol g −1 of acidic groups). The ACFs were applied in the removal of textile dye, Remazol Brilliant Blue R (RBBR), from aqueous solution. The adsorption isotherm and kinetic studies showed that adsorption of RBBR on the ACFs were better described by the pseudo-second order kinetic model and the Freundlich equilibrium model. The maximum adsorption capacity of the ACFS for RBBR was determined to be 292 mg g −1 , which is higher than other adsorbent materials reported in the literature. The adsorption thermodynamic parameters indicated that adsorption process is spontaneous and exothermic. [ABSTRACT FROM AUTHOR]

There is a need for substitution or reduction of toxic chemicals and processing steps in all aspects of chemical manufacturing such as textile dyeing and finishing due to the environmental and economic considerations. In this contribution, green-assembled cupric oxide nanoparticles have been utilized to nanocolor wool fibers considering surface plasmon resonance effect as well as antibacterial and ultra violet protection properties through one single step processing as a cleaner and economic approach. This was carried out by green reduction of copper acetate solution in presence of wool fabric under alkaline condition provided by the commercial ashes of burnt leaves and stems of Seidlitzia Rosmarinus plant. The formation of cupric oxide nanoparticles on the wool fabric confirmed with X-ray diffraction analysis, energy-dispersive X-ray spectroscopy, mapping, Field-emission scanning electron microscope images, Fourier transform infrared spectra and UV–vis spectrum. The brown color of the treated fabrics obtained from light to dark with very good fastness against washing, rubbing, light and alkali spotting. The cupric oxide colored fabrics indicated moderate fastness towards acid spotting due to leaching of metallic and metal oxide nanoparticles in contact with acids. The color change of samples can be potentially used for colorimetric detection of highly concentrated sulfuric and formic as strong inorganic and organic acids during the entire leaching of cupric oxide nanoparticles from the fabric. Further, the treated fabrics exhibited excellent antibacterial actions against both pathogenic bacteria consisting Staphylococcus aureus as a Gram-positive and Escherichia coli as a Gram-negative bacteria with an improvement in tensile strength as well as UV protection properties. Finally, this simple and eco-friendly route can be applied for multifunctional textiles via green assembled cupric oxide nanoparticles in large scale. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

To achieve the Sustainable Development Goal (SDG) 12, it is important to investigate the sustainability of both products and manufacturing facilities to identify the areas to improve. The number of published research works on measuring the eco-indices of fashion products are plenty, while ignoring the measurement of the eco-indices of fashion production facilities. Therefore, this study investigated the environmental sustainability of knit-dyeing facilities linked to fast fashion production in Bangladesh. The Facility Environment Module (FEM) of the Higg index tool 2.0 from Sustainable Apparel Coalition (SAC) was applied to detect the sustainability scores. Multiple case study approach was adopted for this study. Seven tools of FEM related to the environmental management system, energy use, GHG emissions, water use, wastewater, air emissions, waste management, and chemical management were applied to collect data. Scores of these categories were calculated using the FEM tool. Qualitative data was collected through short interviews using a questionnaire. A varying range of scores (from low to high) was found for all the categories. The scores reveal the technical, managerial, and resource limitations on practicing sustainable production approaches in knit-textiles facilities. The overall finding urges all stakeholders, including manufacturers, researchers, buyers, and policymakers, to pay serious attention and reformulate strategies and resources to reduce the negative impact of knit manufacturing on the environment. • Still plenty of scopes for improving sustainability although some factories doing very good. • Worst practice areas were found in air pollution and greenhouse gas emission. • Textiles dyeing and washing operations have the highest environmental impact. • Need robust policies for recycling and reducing waste, and reusing chemicals. • Findings will motivate managers identify areas and improve environmental performances. [ABSTRACT FROM AUTHOR]

Natural dyes are gaining interest due their expected low risk to human health and the environment and biodegradability. In addition, there are ever-growing potential new sources of natural dyes in the form of production waste products that merit consideration for coloration of materials such as textiles. Thus, an innovative approach to waste minimization through source reduction has emerged. In the present study, the potential for using colored liquid waste produced in the steam treatment of eucalyptus wood as a natural coloring matter for textile fabrics was investigated. Specifically, eucalyptus wood extract was used to dye cotton, nylon and wool in an exhaust dyeing process without the addition of the traditional mordanting agents. The resulting dyed fabrics were evaluated for color fastness and it was found that wash fastness of eucalyptus wood processing waste dyed fabrics was very good, while light fastness was typical of natural dyes in the absence of mordants. [ABSTRACT FROM AUTHOR]

We report the development of a cleaner process of producing inkjet printed cotton fabrics with improved color strength, absorbed dye fixation, ink penetration and colorfastness. Inkjet printing of cotton is typically done in the dry state and requires long durations (40–60 min), use of hazardous chemicals and considerable amounts of urea. In this research, ecosteam process has been developed that can print cotton in the wet state in a short time without using urea resulting in better quality, lower costs and lesser harm to the environment. The effect of ecosteam process conditions on the color strength (K/S value), absorbed dye fixation, whiteness index, ink penetration of printed cotton, colorfastness to laundering and crocking were studied. The drying behavior of the wet cotton in ecosteam process was also investigated. An ecosteam process at a temperature of 120 °C for 10 min with relative humidity of 80% was proved to be efficient for imparting reactive print fixation to cotton fabric. The new method of printing improves the K/S value, dye fixation, ink penetration and colorfastness of printed cotton by about 2.44%, 15.79%, 493.47% and 25%, respectively compared to conventional process. Ecosteam process is a cleaner method that can eliminate the use of urea from inkjet printing process. In addition, ecosteam process does not require twice drying after pre-treatment and twice washing after steaming, resulting in higher production efficiency and lower energy consumption. [ABSTRACT FROM AUTHOR]

Dyeing feasibility of wool was investigated with Disperse Red 54, Disperse Blue 183, Disperse Red 153, Disperse Blue 148, Disperse Red 92, and Disperse Yellow 82 in supercritical carbon dioxide. The effects of dyeing temperature, pressure, time, dye mesh number, as well as CO 2 flow on the K/S values and fixation rates of the wool samples were discussed. The results showed that the higher K/S values and fixation rates were obtained with Disperse Red 153 and Disperse Blue 148 in comparison with other disperse dyes. Simultaneously, the K/S values and the fixation rates were improved gradually from 70 °C to 110 °C, 15 MPa to 25 MPa, 60 min to 120 min, as well as 40 mesh number to 100 mesh number for Disperse Red 153, and from 80 °C to 120 °C, 15 MPa to 25 MPa, 60 min to 120 min, as well as 40 mesh number to 100 mesh number for Disperse Blue 148 during supercritical carbon dioxide dyeing procedure. Moreover, excellent permeability and color fastness were obtained whereas the breaking force and tensile strength of the dyed wool fibers were reduced slightly after supercritical carbon dioxide dyeing. [ABSTRACT FROM AUTHOR]

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/m 3 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. [ABSTRACT FROM AUTHOR]

Textile dyeing industries need huge quantity of freshwater for textile dyeing, and discharges a huge amount of wastewater, which can inevitably lead to serious water environmental problems. Genetic algorithm (GA) was used in this paper for the optimization of dyeing production schedule, and it aimed to reduce the freshwater consumption by optimization of scheduling based on dyeing color and depth. Then a scheduling system with a database and a MATLAB program coupling with dynamic genetic algorithm was established and developed. The system was implemented in a typical textile dyeing enterprise which rescheduled about 50–70 orders with unexpected orders insert as a case study. The results showed that compared to traditional production scheduling, the optimizing production scheduling could reduce freshwater consumption about 18.4–21%. [ABSTRACT FROM AUTHOR]

Bio-based dyes for textile dyeing have been widely studied on account of their environmentally friendly approach but in order to be considered as an eco-friendly dyeing concept, additional parameters need to be considered. The purpose of this study was to improve a textile (polyester) dyeing process with madder dye ( Rubia tinctorum L. ), from an eco-sustainable point of view. A life cycle assessment (LCA) has been performed to determine the environmental impacts associated with the dyeing process, at research lab-scale. The identified hotspots were: the solvent and energy use for madder dye extraction and the liquor:fabric ratio in the dyeing phase. Results showed that reduced impacts from both hotspots were needed in order to perform the best in all impact categories studied. Indeed, decreased solvent and energy consumption by ultrasound-assisted dye extraction reduced the global warming potential, photochemical ozone creation potential and air acidification, while minimized water consumption in the after-wash of the dyed fabric was a promising option for improvement in water depletion and eutrophication. [ABSTRACT FROM AUTHOR]

Reactive dyeing of cotton generates a great deal of coloring wastewater containing residual dyes, electrolyte, alkali, and other auxiliaries. Especially for the effluent from the first/initial spent dyeing bath, it may be comprised of as high as 60% of the initial dye dosed, 30–90 g/L of sodium chloride or sodium sulfate, and plenty of sodium carbonate, making it to be the most contaminative effluent among the entire reactive dyeing process. This paper presents a new alternative to regenerate the waste effluent from the first spent dyeing bath through catalytic ozonation with novel catalysts for reuse of the effluent in successive dyeing. Two novel ozonation catalysts, mesoporous carbon aerogel and its supported cobalt oxide nanoparticles, were successfully prepared and used in catalytic degradation of residual dyes in waste effluents with ozone. Degradation efficiency was determined by both decolorization and chemical oxygen demand removal. The result showed novel catalysts could improve both of these two targets. For chemical oxygen demand removal, carbon aerogel supported cobalt oxide strikingly enhanced the efficiency by 30% on the whole comparing to ozonation alone (approximately 50%) without the catalyst. Waste effluents after catalytic ozonation were thereafter reused in successive dyeing in the same process. It has been validated that the waste effluent was successfully regenerated and can be additionally reused twice without sacrificing fabric quality, which cannot be realized in ozonation alone. Color difference of the fabric dyed with the regenerated effluent was within the acceptable tolerance, and excellent levelness and equal colorfastness had also been achieved. This is probably the first study to investigate the feasibility of regenerating highly polluting dyeing effluents for reuse by catalytic ozonation with carbon aerogel materials. With novel catalysts, it could be speculated that catalytic ozonation is a promising technology for in-situ regeneration of waste effluents in textile dyeing plant for reuse. [ABSTRACT FROM AUTHOR]

Textile dyehouses generate high volumes of coloured wastewaters, which require convenient treatment in order to avoid water bodies' contamination, adverse effects to aquatic life and risks to human health. The complete decolourisation of such contaminated waters in a cost-effective manner is still a challenge nowadays. This work focuses on the use of a clayey material as a low-cost adsorbent for a basic textile dye (Red 46), commonly used in acrylic fibres dyeing. The bentonitic clay (49% of montmorillonite) presents a considerable (50 cmol c /kg) cationic exchange capacity and a porosity of 10%. Dye adsorption kinetics was successfully described by a pseudo-second order model, resulting an average kinetic constant of 0.23 g dye g clay − 1 min − 1 . Adsorption equilibrium was reached in 12–24 h and data were successfully fitted to Freundlich and Langmuir equations. The maximum adsorption capacity predicted by the Langmuir model depends on the pH, varying between 217 mg/g at pH 8 and 584 mg/g at pH 9 (25 °C). Increasing the temperature from 25 to 35 °C also led to an increase in adsorbed amounts. In addition to the excellent adsorption performance, the clay showed a great affinity to the dye, indicating high propensity to complete decoulorization of textile dyeing wastewaters. The results obtained in the present work show that a natural, readily-available and cheap material i.e. a bentonitic clay can be used as an effective and environmentally-friendly adsorbent for basic dyes. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

Colour fading treatment of coloured textile products is a hot topic due to its commercial importance. Conventional colour fading technologies involve the use of chemicals which may cause pollution problems and also the evenness of the colour fading effect is difficult to control. As a result, plasma-induced ozone treatment is applied for colour modification and colour fading effect since it is an environment-friendly process that does not generate chemical effluents. Thus, the aim of this study is to investigate the effect of plasma-induced ozone treatment on the colour fading behaviour of reactive dyed cotton fabric. In this study, a cotton fabric was dyed with yellow colour and was then subjected to plasma-induced ozone treatment under different treatment conditions. The colour fading behaviour of the treated fabric was evaluated by instrumental assessment using spectrophotometer and it was found that the colour fading effect was controllable with proper selection of treatment parameters. In addition, a practical analysis was conducted with cotton denim and the results revealed that the plasma-induced ozone treatment could reduce the processing steps and cost when compared with conventional colour fading treatment. [ABSTRACT FROM AUTHOR]

The textile and clothing industry is one of the world most global industries and constitutes an important source of income and employment for several EU countries. The textile manufacturing process is characterized by high consumption of resources such as water, fuel and a variety of chemicals in a long process sequence generating a significant load on the environment. Therefore, in order to meet the consumers demand of eco-friendly products, more sustainable production processes are under investigation in order to reduce the environmental burdens. The feasibility of these alternative solutions has been demonstrated during the EU BISCOL project proposing a new dyeing process as a global alternative for the conversion of raw materials into competitive eco-viable final products. This has been achieved through the integration of enzymatic synthesis of dyes at semi-industrial scale, textile pre-treatment based on plasma technology and synthesis of new auxiliaries at lower environmental impact. A life cycle assessment has been performed to evaluate the environmental impact associated with the development of new strategies for textile industry in comparison to classical dyeing processes. Results based on primary data from the consortium partners involved in the project show that relevant benefits are achievable with an innovative protocol in terms of reducing energy, water and raw materials consumption. [ABSTRACT FROM AUTHOR]

The advanced oxidation technology dominated the disposal of reverse osmosis concentrate in textile and dyeing industry due to its extremely low biodegradability. For resource conservation and sustainable development, the reverse osmosis concentrate was reused in dyeing procedure after being treated properly with combining method of persulfate oxidation and lime-soda softening. Firstly, the refractory organics was oxidized by persulfate thermal activation and the results indicated that the most efficient and economical reaction happened with initial pH = 5.0, 1000 mg/L initial persulfate concentration and 75 °C. In this process, chemical oxygen demand degradation fitted the pseudo-first-order model well and the sodium sulfate concentration increased from 9600 to about 10,350 mg/L. Then, the hardness of reverse osmosis concentrate including Ca 2+ and Mg 2+ hardness was softened efficiently by lime-soda softening technology and appropriate lime and soda concentration was determined to be 150 mg/L and 800 mg/L, respectively. Finally, the effluent was employed as the dyeing water to test the reuse feasibility in dyeing of reactive dyes. Color strength, color difference and color fastness were all used to evaluate the dyeing performance and dyeing results showed that the effluent which was treated properly (COD ≤ 21.5 mg/L, total hardness ≤17.0 mg/L) was available for reuse in reactive dyes dyeing procedure. The study provided a novel method to treat and reuse reverse osmosis concentrate and more importantly, it promoted sodium sulfate concentration and saved its supplementation and dyeing cost in dyeing procedure. [ABSTRACT FROM AUTHOR]

Cleaner production assessment studies were conducted in a textile mill employing wool and acrylic fiber production and subsequent dyeing. A company-wide mass-balance analysis was performed. Various specific consumptions, emissions and waste generations were determined. The performance of the mill was evaluated based on BREF Documents. Water quality analysis indicated that process wastewaters from wool yarn softening, LP-VP printing machines and acrylic yarn washing could be reused in these processes, even without further treatment. Process wastewaters from wool yarn washing and softening in hank dyeing machines could be directly reused in tank washings and/or blended with process waters for direct reuse in the same or other processes. By the application of suggested BAT including wastewater reuse, machinery modifications, reuse of steam condensate, and good management practices, total water consumption may be reduced 35–65%. Substitution of 12 chemicals with more biodegradable and less toxic ones and installation of automatic chemical dosage systems may decrease COD loads about 25–50%. Furthermore, chemical and dyestuff consumptions could be reduced 31%. Energy consumption could be reduced by BAT suggestions including implementation of energy recovery systems for high temperature wastewater flows and flue gas emissions; process monitoring-control and various machinery optimization. Thus, potential reductions in total energy consumption in the mill may be up to 70%. Waste gas emissions could be reduced 25–65%. Waste generations may be decreased 5–10% with good management practices and reuse of especially textile wastes. Pay-back period of the suggested BAT options was found to be generally up to 4 years. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

Abstract: Textile wet processing such as dyeing adds value to the apparel but has the potential to cause significant environmental and human health impacts. The objective of this study is to compare the environmental impacts of fabrics made of spun-dyed modal with conventionally dyed modal fabrics (for production in Austria, system "cradle-to-factory gate"). The chosen functional unit is one kilogram of black modal knitted fabric. We assessed energy use, GHG emissions, water use and the impact categories covered by CML 2001 method. We found that the cradle to gate production of spun-dyed modal fabric has 50% lower energy use, 60% lower carbon footprint, and requires only 50% of water and has significantly lower (40–60%) environmental impacts compared to conventionally dyed fabric. Sensitivity analysis with liquor ratios and number of washing cycles does not substantially change the above results. Conventional dyeing in China leads to four-fold higher GHG emissions per kg fabric compared to spin-dyeing in Austria. Finally, we described linkages of sustainable innovation with business value creation. We showed that spin-dyeing can significantly reduce costs for value chain actors, helps reducing the environmental footprint of end products, enhances reputation of brands and retailers, and can contribute to mitigating global problems while catering for the rising demand for clothing fuelled by ever growing world population. [Copyright &y& Elsevier]

Abstract: In application of vat dyes the substitution of non-regenerable reducing agents such as Na2S2O4 by cathodically regenerable reducing agents offers great ecological advantages. In a demonstration project a 45 A multi-cathode electrolyser successfully was coupled to a dyeing apparatus for package dyeing with a capacity of 1–10kg material. Iron-complexes with triethanolamine and Na-d-gluconate were used as cathodically regenerable reducing agents. Dyebath regeneration was performed by ultrafiltration. Substantial reduction in chemical consumption and reduction in wastewater volume, released from the dyeing process could be demonstrated. Quality of dyeings was assessed with regard to levelness and iron content analysed in the dyed samples. [Copyright &y& Elsevier]

As a clean technology, ultrasonics has been widely explored in textile dyeing. Mordanting is commonly used for the achievement of efficient textile dyeing, however little attention has been paid on application of ultrasonics in mordanting. This study investigated sonochemical mordanting and its efficiency in subsequent dyeing. Ultrasonic bath, together with traditional water bath and magnetic stirring bath were investigated. Soy protein and F. Artemisiae argyi (FAA) were used as a mordant and natural dye, due to the their natural compatibility with cotton as well as biological properties. All the materials used in this work were natural with very little chemicals (present no harm to the environment) applied. Results showed that while soy mordanting in water bath can significantly increase fiber natural dye uptake, the dye affinity can be enhanced further when ultrasonic irradiation was applied. Ultrasonic mordanting was found to be able to produce higher fabric color strength (K/S) while consuming less soy protein when compared with other mordanting baths. Less weight increase as a result of ultrasonic irradiation can also provide cotton fabric with softer handle than those processed in traditional water bath. UV protection of dyed fabrics was found to be significantly improved from the control sample, with samples processed with ultrasonics showing the greatest improvement. In addition to the increased dye affinity as a result of soy mordanting, fabric bio function of antibacterial property was found to be simultaneously and successfully achieved. • Applying ultrasonics in mordanting process prior to dyeing, which is rarely reported. • Natural dye uptake can be increased with less mordant required through sonochemical mordanting. • Fabric handle can be improved along with the increased color strength of fabric through sonochemical mordanting. • UV protection and antibacterial properties of fabric can be improved significantly through the process. • A successful development of a green and efficient process in cotton dyeing and bio finishing. [ABSTRACT FROM AUTHOR]

Clean dyeing technologies for polyester textiles, particularly waterless dyeing, have been studied extensively in recent decades. In the present work, a new waterless dyeing technology, the silicone medium dyeing, for polyester textiles had been investigated. The dyeing process of polyester textile in the silicone medium was optimized by determining the dyeing temperature, holding time, type and dosage of dye accelerator. The dye uptake of disperse dye and the fastness properties of the dyed polyester were equivalent to those of conventional water-bathed dyeing. After dyeing, polyester textile had a better color levelness. From the TGA and XRD results, it can be proved that silicone medium has no adverse effects on the fiber and can be used as a dyeing medium. The influence of the increase of halogen in the diazotized component on the affinity, dye uptake, diffusion coefficient, and other parameters was obtained by analyzing the dye uptake of C.I. Disperse Orange 44 and C.I. Disperse Yellow 163. These parameters formulate guidelines for the selection of disperse dyes for silicone medium dyeing system. To verify the feasibility of industrialization, pilot-scale dyeing was carried out. The results showed that, as compared to aqueous dyeing, higher colorfastness and better color levelness were obtained from silicone media. Therefore, this eco-friendly dyeing technology has considerable potential to become a mainstream dyeing method in the foreseeable future. • The use of water is avoided throughout the dyeing and washing process. • Dye uptake can be adjusted by accelerant. • Superior fastness and leveling. • The diversified styles of textiles are developed and achieved a pilot test. [ABSTRACT FROM AUTHOR]

Artificial dyes from petrochemicals are extensively used in the numerous sectors. They have adverse effects on human health and environment. Economical and bio-friendly approaches are needed to extract and produce dyes in an ecological manner to replace the hazardous and toxic artificial ones. In this regard, exploiting the potential of natural dyes sources from unconventional plant species presumes a sustainable management of natural resources, and the development of eco-friendly processing extraction technologies with high efficiency, low toxicity and low environmental impacts. In Madagascar, five plant species including Acridocarpus excelsus , Ceriops tagal , Rhizophora mucronata , Woodfordia fruticosa and Xylocarpus granatum are traditionally used as sources of natural red dyes by Malagasy craftspersons for textile dyeing at a very small scale. This original work is based on this assessment. It demonstrated that biopigments extracted via a low-toxicity and highly-efficient pressurized liquid extraction (PLE method from barks adventive roots collected from these five plant species of Madagascar could be used as red dyestuffs. These dye plant extracts have been demonstrated as having, in term of colors, great pH stabilities within a pH range of 3–9 and thermal stability up to 200 °C. By their chemical properties, antioxidant and antimicrobial properties that could meet industrial application requirement. We are proposing lines of research that would improve the industrial sustainability and economic viability of the production of pigments extracted from Malagasy plant raw materials. The potential of PLE technique paired with eco-friendly solvents as an alternative method for the extraction and recovery of natural dyes is also discussed here. The valorization of these plant species using green technologies could enable the development of local sectors in Madagascar with wide potential of applications. However, issues related to development ethics, preservation of biological heritage and sustainable resource management must be carefully considered. • Coloring properties of dyestuffs from typical plant species from Madagascar are highlighted. • Plant barks are promising sustainable sources of red dyestuff materials. • W. fruticosa roots and A. excelsus barks revealed interesting coloring and antioxidant properties. • Pressurized liquid solvent extraction of pigment is more efficient than traditional decoction. • Their properties generate new areas of industrial applications beyond their traditional use. [ABSTRACT FROM AUTHOR]

Traditional textile dyeing industry usually use chemical pigments and dyes, which bring about a large amount of colored wastewater causing serious environmental pollution. Replacing the traditional high pollution dyeing methods to realize eco-friendly dyeing is very important to the textile dyeing industry, structural colorization maybe one of the most promising methods. In this study, a novel approach was proposed to fabricate eco-friendly coloration of textile originating from polydopamine (PDA) structural color nanofilm with high colorfastness. Four different bright colors were obtained by the polymerization of PDA nanofilm with different reaction times on cotton fabric. However, capillary tension during the formation of PDA nanofilm and weak interaction with fabric substrate resulted in cracking and poor colorfastness. The novel synthesis adhesive of poly (glycidyl methacrylate co-polyethylene glycol methyl ether methacrylate) containing reactive epoxy groups was used to avoid cracking and improve the colorfastness which would form covalent bond on the interface between structural color film and substrate. Therefore, crack-free PDA structural color nanofilm with high colorfastness on cotton fabric surface was obtained. This facile approach provide novel idea for eco-friendly dyeing different kinds of textiles with structural color boosting the cleaner dyeing in textile industrial field. • Four different bright structural colors were obtained originating for PDA nanofilm. • P (GMA-co-PEGMA) containing reactive epoxy group was synthesized and used as adhesive. • Crack-free PDA nanofilm structural color with adhesive on cotton fabric was obtained. • PDA structural color film with adhesive on cotton fabric achieved high colorfastness. [ABSTRACT FROM AUTHOR]

To circumvent wastewater concern of textile industry and cost-effectively utilize waste cooking oil, this study replaced water with waste cooking oil (WCO) in reactive dyeing, and enabled circulated utilization of WCO without jeopardizing dyeing quality, as well as value addition to WCO industry. Current textile dyeing process discharges tremendous amount of wastewater comprised of high concentrations of salts and hydrolyzed dyes. However, none of the existing remediation methods, such as optimization of dyeing processes, chemical modifications of fibers and post-dyeing treatments, showed effectiveness or efficiency. In a dual-phase reactive dyeing, oil and water were used to disperse dye particles and swell cotton fibers. Dyes could be quickly dissolved in water phase and adsorbed into cotton fibers from the interface of water and oil. Though non-edible WCO could be used as a medium for salt-free reactive dyeing, WCO degraded during dyeing and showed gradually deteriorated dyeing quality if repeatedly used. For the first time, this work quantified influence of glycerol and sodium fatty acid, two main WCO hydrolysates, on dyeing results, and revealed the influencing mechanism. As a solution, alkaline refinement was applied after each dyeing cycle to revive functionality of the WCO medium, and could effectively enable WCO reusable in reactive dyeing. Effluent from conventional reactive dyeing could contain up to 100 g/L electrolytes and 50% of initially added dyes, while effluent from WCO reactive dyeing contained no electrolytes and minimal amount of dyes, and could be discharged after simple treatment. Regarding value addition to WCO, textile route might also be economically favorable than biodiesel route. Overall, the WCO reactive dyeing system could have good industrialization potential as a cleaner textile wet process. Image 1 • Waste cooking oil (WCO) was used for cotton dyeing with constantly good quality. • Circulated dyeing of cotton could be realized with minimal waste discharge. • Application of WCO in cotton dyeing had high industrialization potential. • Effluent of WCO dyeing met highest discharge standard with simple treatment. [ABSTRACT FROM AUTHOR]

Natural dyes are gaining more attention due to their non-toxic and eco-friendly nature. However, dyeing with natural dyes has limitations and is challenging to apply, as they possess some inherent demerits, such as less or no attraction towards the textile substrate, requirements of mordant, fixers and other chemicals for fixation onto the textile substrates, lower yield and color fastness, which have restricted their potential in the industrial-scale application. Plasma treatment has proved that it can be used as an environmentally friendly approach to improve dyeing uptake of textiles with natural dyes. This review addresses the effect of plasma treatment on surface modification of most used natural (wool, cotton, and silk) and synthetic fibers (polyester, nylon, and acrylic) and its subsequent effects on their dying with natural dyes. This review provides a clear view of the combination of cleaner pre-treatment and sustainable resources for dyeing textiles to reduce wastewater and toxic chemicals for cleaner production. Image 1 • The importance of natural dyes in the cleaner production of textiles is reviewed. • Types of plasma treatment and their advantages and disadvantages are reviewed. • The applications of natural dyes on textiles, enhanced by plasma, are reviewed. • The mechanisms of plasma action on natural dyeability of textiles is discussed. • The effect of plasma and natural dyes in cleaner dyeing of textiles is emphasized. [ABSTRACT FROM AUTHOR]

The (co-)pyrolysis of textile dyeing sludge and spent mushroom substrate was conducted to characterize their thermal behaviors and by-products. The devolatilization of textile dyeing sludge mainly occurred between 150 and 500 °C, while the decomposition of inorganic matter as well as the secondary cracking of coke and tar happened between 500 and 1000 °C. The addition of spent mushroom substrate increased the release rate at the devolatilization stage of textile dyeing sludge and their blends due to its higher volatiles content. The enhanced co-pyrolysis performance occurred mainly at the high temperature. The melting of inorganic matter was enhanced with the temperature rise but weakened with the addition of spent mushroom substrate. Sulfur mainly existed as sulfate in textile dyeing sludge and as organic sulfur in spent mushroom substrate. With the temperature rise, nitrogen-containing compounds formed more stable compounds. Spent mushroom substrate promoted the formation of nitrogen oxides by converting nitrogen to an inactive form. Sulfates were decomposed at high temperatures partially turning into sulfide. 30% spent mushroom substrate increased the relative sulfate content at 800 °C and fixed sulfur into inorganic compounds. The relative contents of aromatics, and nitrogen-containing compounds rose in the bio-oils, whereas alkanes fell with the elevated temperature. Spent mushroom substrate enhanced the formation of aromatics and reduced the yields of nitrogen-containing compounds, and acidic volatiles. The co-pyrolysis appeared to improve the bio-oil quality and the pyrolytic performance of textile dyeing sludge. Image 1 • (Co-)pyrolysis of textile dyeing sludge and spent mushroom substrate were studied. • Textile dyeing sludge degraded fastest at 718.8 °C due to its high ash content. • Nitrogen and sulfur mainly existed as protein and sulfate in textile dyeing sludge. • Co-pyrolysis increased quaternary-N and sulfates in residuals. • The addition of spent mushroom substrate yielded more aromatics and less acids. [ABSTRACT FROM AUTHOR]

The textile dyeing is a significant worldwide economic pillar of the industry mainstay of the region's industrial economy. Therefore, significant attention should be paid to its emitted volatile organic compounds (VOCs) regarding their potential adverse effects on ecosystems and human health. In this study, a spray tower (ST) (preferential elimination of hydrosoluble VOCs) and biofilter (primary removal of particle-free VOCs) were used in combination. Three techniques, including gas chromatography-mass spectrometer (GC-MS), e-nose, and Proton transfer reaction time-of-flight mass spectrometry (PTR-TOF-MS) were used to accurately identify the associated VOCs profile. In total, 50 types of VOCs, with total concentrations ranging from 1.26 to 2.79 mg m−3, were detected from the outlet of the TDWTP over a 90-day treatment period. The highest level occurred for nitrogen- and oxygen-containing compounds (NAOCCs), followed by aliphatic hydrocarbons (AIHs), aromatic hydrocarbons (AHs), and halogenated hydrocarbons (HHs). Average removal efficiencies (REs) of the four studied VOC groups (NAOCCs, AIHs, AHs, and HHs) were 66.7%, 67.9%, 11.7%, and 52.1%, respectively. Proteobacteria dominated the biofilter, followed by Actinobacteria, Firmicutes, and Bacteroidetes. A positive correlation was observed between the relative abundance of Proteobacteria and the RE of NAOCCs, with RE significantly increased from 38.1% (day 1) to 83.2% (day 90). The degradation of these organic pollutants, such as NAOCCs, may be mainly performed by the dominant genus, such as Acidithiobacillus and Metallibacterium, as predicted by PICRUSt. A respiratory health risk evaluation demonstrated that the cancer and non-cancer risks of typical VOCs were dramatically reduced after the above-mentioned purification. The combined results indicate that the ST-biofilter is an efficient approach for the end-of-pipe treatment of exhausted gas in TDWTP and helps attenuate human health risk. Image 1 • Pilot-scale end-of-pipe removal of VOCs from textile dyeing wastewater treating plant. • ST-BF reactor show high and stable removal ability to odorous VOCs. • Bacteria increased in relative abundance contributed highly to VOCs removal. • Strong correlation among Proteobacteria and REs of NAOCCs was observed. • Health risks of target VOCs decrease significantly after the treatment. [ABSTRACT FROM AUTHOR]