Electro-assisted activation of peroxymonosulfate in the presence of chloride ion for degradation of sulfamethoxazole

Abstract

A laboratory-scale electrochemical reaction tank was self-designed for the degradation of sulfamethoxazole (SMZ). Coupling electrocatalysis (EC) with personoxysulfate (PMS) and chloride ion (Cl−), the degradation system of EC + PMS + Cl was established. The degradation efficiency of the EC + PMS + Cl system for SMZ (10 mg/L) reached 100% within 20 min, and the degradation process of SMZ conforms to the first-order kinetics. EC + PMS + Cl system also has good degradation efficiency for other organic pollutants or polysaccharide wastewater (real wastewater) from coriolus versicolor. The electrochemical performance test shows that TiO2/RuO2–IrO2 electrode not only has a good chlorine evolution effect but also has good stability. •OH and active chlorine play a major role in the degradation system. Theoretical calculation (DFT) and XPS analyses confirm that the RuO2–IrO2 site as an active center activates PMS and Cl− into active oxygen and active chlorine, and the TiO2 site as an active center activates molecular oxygen into active oxygen. The results of liquid chromatography and mass spectrometry (LC-MS) and Toxicity Estimation Software Tool (TEST) showed that the water quality of SMZ after 20 min of degradation was almost harmless. Therefore, this research work will provide a new vision for the electrocatalytic degradation of organic wastewater.