Effect of Process Parameters and Bath Composition on the Dyeing of Cotton in Catalases Treated Bleaching Bath

Abstract

An alternative method was developed to treat bleaching bath containing fabric with catalases enzymes (Bactosol SAP) along with designing a process that required less washing cycles needed after the bleaching process. The objective was to decompose hydrogen peroxide residues in the bleaching bath with catalases enzyme to be reused again for dyeing of cotton fabrics. Enzyme dyes and auxiliaries dosage was optimized to get neutral pH of bleached bath in relation to process parameters such as concentration (1-5 g/l), temperature (40-80 °C) and time (5-25 min). For dyeing in bleached bath effluent, reactive dye, electrolyte and alkali amounts were also optimized to acquire same color strength value as that of conventional dyeing method. The catalases was treated at 60°C for 20 min with 5% dosage, which transpired that the peroxide residues could be decomposed enough to give accurate neutral pH. It was also observed that with an increase in the concentration of dyes and auxiliaries (dye, salt, alkali) the color strength (k/s) increased significantly, resulting in better dyeing without excessive washing and rinsing cycles. The results of this research work suggested that bleaching bath can be reused for dyeing of cotton fabrics with reactive dyes if optimum amount of dyes and auxiliaries are used.