Abstract
Dyeing of cotton with sulfur dyes is preferred to develop deep shades at low cost with all-round good fastness, except to chlorine. Sulfur dye is water insoluble; dyeing of cotton with this dye necessitates reduction and solubilization of dye with sodium sulfide at boil followed by oxidation with acidic potassium dichromate. Application of dichromate develops stiffness on dyed cotton due to the precipitation of chromium compounds, causing occasional change in tone and increasing the solid content of the discharged waste water. In this work, the feasibility of laccase as a potential oxidizing catalyst was studied for the oxidation of sulfur-dyed cotton in an attempt to substitute toxic dichromate. Attempts were also made to precipitate unused sulfur dye from the exhausted dyebath using laccase and reuse of the precipitated dye for the fresh dyeing of cotton.
Get full access to this article
View all access options for this article.