A sustainable approach for cotton bioscouring: reuse of the pectate lyase containing treatment bath.

Enzymatic scouring of cotton has established itself (slowly) as a green alternative to alkaline scouring in the textile industry, mostly due to more environmentally friendly processing at lower pH and temperatures and its less aggressive action on the cotton fibers. However, among other limitations, enzyme costs have contributed to impeding its wide acceptance and use. For the first time, in this study, the recycling of the bioscouring bath was evaluated, unlike most current bioscouring that is performed using fresh enzyme solution. Bioscouring of raw knitted cotton fabric was carried out for 30 min with a commercial pectinase (BioPrep® 3000L) at 55 °C and pH 8.5. About 89% of the recovered pectate lyase-containing scouring bath was completed with 11% of fresh enzyme solution and reused in a new bioscouring process under the same conditions. Up to ten reuse cycles were possible maintaining the level of pectin removal and without significant loss in quality of subsequent dyeing. A detailed analysis of the pretreated fabrics is presented. Reusing the scouring bath, reducing the intensive consumption of input materials (enzyme, water, and chemicals) and wastewater generation can be possible, making bioscouring a more attractive and sustainable technique. The process demonstrated is promising and its industrial application is feasible.

Preparation of cationic cotton through reaction with different polyelectrolytes.

Cationization of cotton fabrics was performed by exhaustion procedure utilizing four different reagents provided with quaternary ammonium groups: poly diallyldimethylammonium chloride (PDDACl), poly acrylamide-co-diallyldimethylammonium chloride (PAcD), poly[bis(2-chloroethyl) ether-alt-1,3-bis[3-(dimethylamino)propyl]urea] quaternized (P42) and 3-chloro-2-hydroxypropyl trimethyl ammonium chloride (CHPTAC). Pretreated samples were dyed using Reactive Red 195 dye. The cationic fabrics were analyzed by colorimetric and fastness properties, zeta potential, SEM, FTIR and an estimate of the bactericidal effect. Cationic cotton treated with PDDACl and CHPTAC showed a higher affinity for the reactive dye, with color strength (K/S) values varying from 41 to 48, against 32 for conventional dyeing. P42 presented competitive results with K/S of 27-28. The cationic dyeing considerably reduced the amount of effluent, especially for the CHPTAC samples, which requires a single washing bath for complete removal of unfixed dye. The PDDACl and P42 samples presented bactericidal activity. Supplementary Information: The online version contains supplementary material available at 10.1007/s10570-021-04260-4.