Multiple Reuse of Electrocoagulation Treated Reactive Dyeing Wash-Off: Colorimetric Properties and Water Saving

Abstract

Dyeing wash-off operations in textile industries quite water intensive resulting into the generation of highly polluted wastewater. This study evaluated the treatment efficiency of electrocoagulation process to decolorize the synthetic effluent of CI Reactive Yellow 145 and then, the treated effluent was reused for 08 subsequent wash-off cycles of textile dyeing. The process parameters (Electrolysis time, applied current density and pH) were optimized and the maximum colour removal efficiency (98%) was achieved at pH 7, 10 minutes treatment time and current density of 90 A/m2. The fabric quality was assessed in terms of Colour difference and wash fastness properties. The Colour difference values of all dyed fabric samples up to 8 reuse cycles were ranged 0.38 to 0.85 which is industrially acceptable quality limit (ΔEcmc < 1). The wash fastness and Colour strength properties were also comparable to that of conventionally washed off fabric samples. However, an increase in pH, COD, TDS and turbidity was observed after every reuse but it did not deteriorate the quality of dyeing. This approach of reuse of electrocoagulation treated dye wash-off liquor up to 8 cycles provides a sustainable solution for textile industry.