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

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 mgL-1, current density = 100 mAcm(-2), electrode distance = 20 mm, initial pH = 7.0, and NaCl dosage = 8000 mgL-1), the removal rate of DMF was >80 % at 90 min, and the energy efficiency evaluation indicator was lower than 1.0 kWh 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 N-2, 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.