A greener approach to cotton pre-treatment using bentonite clay

Cotton dyeing and printing requires a number of preparatory processes involved the use of various chemicals and eventually creates massive pollution load on effluent which disposed in the environment directly or partially treated consequently increases the health hazard. In this work cotton knitted fabric was scoured and bleached by naturally occurring clay ‘Bentonite’ as an alternative of auxiliaries. The wetting power, detergency, sequestering power and stabilizing action of bentonite clay was tested thoroughly. The scouring and bleaching efficiency and dyeability with a bi-functional reactive dye were evaluated on differently pretreated samples. The residual pretreated liquors were analyzed for ecological parameters including pH, Total dissolved solids, chemical oxygen demand, and biological oxygen demand (BOD5). In comparison with conventional auxiliaries, bentonite clay showed acceptable results. The scouring and bleaching performances of all pretreated fabrics was satisfactory. All samples were evenly dyed and there was no noticeable color difference. It also observed that bentonite clay treated liquors create less pollution when compared to the conventional treated liquors. Finally, cost of bentonite process was calculated and compared with conventional.