Comparative degradation study of remazol black B dye using electro-coagulation and electro-Fenton process: Kinetics and cost analysis

Abstract

Water pollution from textile industries is a great concern in developing countries. To address the textile wastewater treatment, this study investigated the removal of chemical oxygen demand (COD), color, dye, and turbidity from synthetic textile wastewater containing remazol black B (RBB) dye under electro-coagulation (EC) and electro-Fenton (EF) processes by using an electrochemical cell comprising two stainless steel electrodes. The impacts of the addition of Fe2+ concentration, H2O2 concentration and their dual effect on the process performances and operating costs of the processes were also assessed. Over 76 %, 94 %, 95 % and 95 % of COD, color, dye, and turbidity removals were observed, respectively, from the EF process after 50 min of treatment. The EC process was efficient to degrade dye (86.5 %) and to remove color (91 %), however, the process was not effective to remove turbidity (60.4 %) and to mineralize the dye (19.8 %). About 4 times higher dye mineralization was observed in the EF process as compared to the EC process. The kinetics analysis demonstrated that the degradation process of RBB dye followed first order kinetic model and the value of reaction rate constant was 1.5 times higher in the EF treatment process than achieved in the EC treatment process. The analysis of operating costs suggested that the EF processes had about 3 times lower operating costs than the operating cost evaluated for the EC process. Therefore, the outcome of this study revealed that the EF process can be a good option for the treatment of textile wastewater for the sustainable development of textile industries.