Enhanced advanced oxidation treatment through the synergy of chloride ion activation and electro-Fenton process

Abstract

A photoelectrocatalytic system has been developed utilizing the WO3@BiVO4 photoanode and the oxidized carbon black (CB) cathode, enabling the synergistic advanced oxidation treatment by combining chlorine radicals and hydroxyl radicals. The WO3@BiVO4 heterojunction is prepared through hydrothermal growth of BiVO4 onto the surface of WO3 synaptic structure. The as-prepared WO3@BiVO4|Pt system demonstrates a remarkable degradation efficiency of organic pollutants with 97.1 % in 30 min under visible light irradiation with a 1.2 V bias, which is 1.24 times higher compared to the WO3|Pt system. Furthermore, even when utilizing actual seawater as the electrolyte, the treatment efficacy remains high at 92.8 % within 20 min. The oxidized CB cathode is obtained by calcining commercial CB in the air atmosphere. The WO3@BiVO4|CB system achieves the degradation efficiency of 85.9 % within 10 min in simulated seawater, utilizing the electro-Fenton process at 0.2 V. The WO3@BiVO4|CB system effectively removes organic pollutants through the synergistic effect of combining the WO3@BiVO4 photoanode with CB-A cathode. Additionally, impressive degradation efficiency of 97.8 % is achieved in 15 min when using simulated seawater as the electrolyte. The •OH, •Cl, and •Cl2− play the key role in the WB|CB-A synergistic system. The combined action of anodic active chlorine radicals and cathodic electro-Fenton process in the WO3@BiVO4|CB system demonstrates effective microorganism sterilization, resulting in a 92.5 % reduction within 15 min