Youzheng Chai, Ming Gao, Gong Zhang, Xiangyun Liu, Qing Mu, Huijuan Liu
Insufficient chlorine evolution reaction (CER) selectivity over the competing oxygen evolution reaction (OER) limits chloride-mediated electro-oxidation for deep mineralization and reuse of Cl--laden PVC wastewater, particularly under near-neutral and 0.25-1 mol/L Cl⁻ ranges. Here, RuO2/Ti4O7 porous anode was prepared to enable excellent CER while limiting OER activities through leveraging the interfacial electronic coupling effect between oxygen vacancy-rich Ti4O7 support and Ru sites. The low Ru loading RuO2/Ti4O7 delivered 60-93% Faradaic efficiency and higher active species production than DSA in neutral solutions from wide Cl⁻ range. A flow-through electrochemical reactor using RuO2/Ti4O7 was constructed and maintained >88.9% TOC removal in 360 h continuous wastewater treatment with 0.25-1 mol/L Cl- concentration ranges. The high efficiency of Cl-mediated ·OH formation via RuO2/Ti4O7 ensured the sustained mineralization pathway, and showing >93.5% TOC removal during 400 h continuous treatment within complex actual wastewater. Effluent treated by this electrochemical system directly meets ion-exchange membrane electrolyser reuse standards (influent TOC <10 mg/L), enabling complete salt water recovery and confirming its huge potential in chlor-alkali industry.