A Novel Approach in Dyeing of Cotton Fabric Without Salt

Abstract

Textile dyeing is a complicated process involving the addition of a large number of dyes and auxiliaries to achieve the exact shade. The wastes generated in this process are huge and polluting to the land and the surrounding environment. The main cause of this effluent problem happens to be the addition of salt in reactive dyeing. Hence rather than finding a method to dispose these hazardous wastes generated it would be better to devise a safer system of dyeing. Salt is inevitable in the conventional method because it masks the zeta potential developed by cotton fabric when immersed in water. This masking of the zeta potential facilitates the negatively charged dye to get attracted to the fabric. But the same effect can be produced with the help of electric current by passing positive charges to the fabric. The quality parameters, such as K/S value, fastness and uniformity, of fabric dyed with help of electrical current is also similar to that of fabric dyed using conventional method. By doing this the TDS content of the effluent is greatly reduced and reduces sludge formation. This also poses a chance for reuse of dye liquor which will minimize the consumption of dyes and reduce cost. It also has an ease of implementation in all dyeing units by slight modification of the present working style.