In the past decade, water scarcity has become major concern and is going to be reality in future too. At the same time textile is necessity which needs a billion liters of fresh water for its processing. Out of this 16 % of water is only used for dyeing of textile materials. In a quest to develop a sustainable approach to reduce water scarcity, an attempt has been made to minimize water consumption in textile wet processing. In this work, an eco-friendly glycerine based eutectic solvent (GES) was prepared by using choline chloride, urea and glycerin to reduce water consumption in polyester dyeing. The prepared solvent was characterized in terms of FTIR. Dyeing parameters like time, temperature and pH were optimized for dyeing of polyester using GES as a dyeing medium. The efficacy of dyeing was analyzed by colour strength and colour performance properties; sublimation, wash and light fastness. In comparison with conventional dyed polyester overall dyeing performance was found to be better without affecting tensile strength of polyester which remains almost same whereas thermal stability of solvent dyed polyester was slightly improved compared with aqueous dyed polyester. The results obtained from this study suggest that the GES as a polyester dyeing medium can be a green approach in dyeing of polyester.

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Purpose Textile industry is considered to be one of the largest consumers of water. There needs to be an alternative for water in textile wet processing. Solvent dyeing can be an approach to replace the use of water in dyeing for water conservation. Design/methodology/approach In this study, the dyeing of polyester was carried out using conventional and solvent dyeing methods. The solvent used was non-aqueous, deep eutectic solvent (DES) prepared using choline chloride and urea. Dyeing parameters such as time, temperature and pH were optimized for a concentration of dye using the solvent and were compared with the conventional dyeing. Findings The prepared solvent was characterized in terms of Fourier-transform infrared resonance and 1H and 13C nuclear magnetic resonance to analyze the reaction between choline chloride and urea. Dyeing performance in terms of K/S and fastness properties of dyed fabrics were evaluated and found to be at par against conventional dyeing. Originality/value Use of DES as a dyeing medium is a novel approach in the textile industry.

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Purpose Dyeing of silk fabric was studied to increase dye uptake using eco-friendly glycerine based eutectic solvent (GES), which acts as a swelling agent. Design/methodology/approach The swelling behaviour of silk fabric in GES was analyzed using three-dimensional laser scanning microscope. Dyeing parameters such as time, temperature and GES concentration were optimized using design of experiments. Findings In total, 5.34 F-value and 0.0014 p-value of ANOVA represent that the model is significant. An optimized GES assisted dyeing was carried out with two different classes of dyes such as Acid Blue 281 and Acid Red 151 and further compared with that of conventional aqueous dyeing method. Originality/value At 70°C, silk fabric achieves desired colour strength after 35 min of dyeing (10 min lesser than conventional) using GES assisted dyeing method. % Dye exhaustion of GES assisted dye bath was carried out and found to be very good. Fastness properties such as washing, light and rubbing fastness of conventional and GES assisted dyed silk fabric showed comparable results.