MnO2-RuO2/CFC composite electrode used in the treatment of high‑chlorine organic wastewater: Preparation, performance, mechanism and application feasibility

Abstract

MnO2-RuO2/carbon fiber cloth (MnO2-RuO2/CFC) composite electrode was successfully prepared by electrodeposition-calcination process and used to treat high‑chlorine organic wastewater (HCOW). The MnO2-RuO2/CFC composite electrode showed excellent electrocatalysis oxidation ability compared with that of CFC electrode relying on the synergistic effect between MnO2 and RuO2. Under the optimal treatment condition of high‑chlorine N,N-dimethylformamide (DMF) simulated wastewater (DMF initial concentration = 2000 mg·L−1, current density = 100 mA·cm−2, electrode distance = 20 mm, initial pH = 7.0, and NaCl dosage = 8000 mg·L−1), the removal rate of DMF was >80 % at 90 min, and the energy efficiency evaluation indicator was lower than 1.0 kW·h m−3. The active chlorine was the main oxidation species, while hydroxyl radical played the auxiliary role. DMF can be degraded into methylformamide, methanol, and hydrazine and then mineralized into N2, CO2 and H2O. MnO2-RuO2/CFC composite electrode can be used at least 10 times in the treatment of high‑chlorine real cephalosporin synthetic pharmaceutical wastewater, and the toxicity of the treated wastewater was significantly weakened, indicating the feasibility of the application of MnO2-RuO2/CFC composite electrode in the treatment of HCOW.