Different behaviours of biologically textile wastewater treatment using persulfate catalyzed electrochemical oxidation process on Ti/BDD and Ti/SnO2-Nb2O5 anodes

Abstract

Textile wastewater effluent includes high concentrations of pollutant such as dyes, detergents, and chemical auxiliaries that bring many negative impacts to humans and the environment. In this study, biologically textile wastewater effluent was first time treated using electrochemical oxidation catalyzed by persulfate on Ti/BDD and Ti/SnO2-Nb2O5 anodes. The results show that persulfate catalyst only significantly increases the electrochemical process efficiency at the Ti/BDD anode, but not at the Ti/SnO2-Nb2O5 anode. The optimized operation conditions at the Ti/BDD anode are: [NaCl] 3 g/L, [PS] 2 g/L, applied current density 4.16 mA/cm2, pH 7.5, stirring speed 200 rpm, electrolysis time 120 minutes that removed 94.78% color, 64.57% COD, and 41.57% TOC in textile wastewater. The optimized operation conditions at the Ti/SnO2-Nb2O5 anode are: [NaCl] 3 g/L, [PS] 1 g/L, applied current density 4.16 mA/cm2, pH 7.5, stirring speed 200 rpm, electrolysis time 150 minutes that removed 73.04% color, 41.32% COD, and 39.22% TOC. Detected oxidant radicals during the electrochemical oxidation processes could contribute to the oxidation of organic matters in biologically textile wastewater.