Electrocatalytic degradation of reactive dyes in high sulfate wastewater by synergistic effect of anode and cathode

Abstract

A carbon black/polytetrafluoroethylene(C/PTFE) gas diffuser electrode was prepared by the roller compaction method and its micro-structure was characterized. An electrocatalytic oxidation system using a boron-doped diamond as anode and a C/PTFE gas diffuser electrode as cathode was constructed. The reactive brilliant blue X-BR in high sulfate wastewater was treated cooperatively by combining sulfate activation technology at anode with in-situ synthesis of H2O2 technology at cathode. The results showed that when the prepared C/PTFE electrode was used as the cathode, the removal effect of active brilliant blue X-BR in electro-activated sulfate system was better than that in platinum(Pt) cathode system and stainless steel(SS) system. According to the quenching experiment, the interaction between the highly active substances such as SO4·- and ·OH produced by the electrochemical system of BDD/(C/PTFE) provided the bulk sustainable oxidation capacity for the degradation of reactive brilliant blue X-BR, and the contribution of these two substances to the removal of active brilliant blue X-BR were 54.51% and 25.75%, respectively. A quadratic model of TOC removal rate and unit energy consumption in electrochemical oxidation system was established. The operational parameters of reactive brilliant blue X-BR degradation were optimized by experimental design matrix. Under optimized conditions (initial pH=5.0, current density=120 mA/cm2, CNa2SO4=0.25 mol/L,Cactive brilliant blue X-BR=1 000 mg/L), and electrolysis for 120 min, the removal rate of TOC in wastewater was 63.86% and the unit energy consumption of the system was 256.02 kW·h/kg. The reactive brilliant blue X-BR in water could be completely mineralized by continued electrolysis to 240 min. The results provide theoretical support for the dual-electrode collaborative electrocatalytic oxidation treatment of high sulfate organic wastewater.

Keywords

• electrocatalytic oxidation
• bdd anode
• c/ptfe gas diffusion cathode
• electroactivated sulfate
• doehlert experimental design matrix