Efficient electrochemical oxidation of refractory organics in actual petrochemical reverse osmosis concentrates by Ti/SnO₂-Sb mesh anode

The efficient treatment of refractory organics in reverse osmosis concentrate (ROC) is a critical issue for achieving emission reduction or even zero emission in the petrochemical industry. A simple and efficient electrocatalytic process was proposed for treating actual petrochemical ROC using a highly active self-assembling Ti/SnO2-Sb anode. The Ti/SnO2-Sb anode was prepared by using citric acid (CA) and ethylene glycol (EG) as precursors, with a mole ratio of Sn:Sb of 5:1 and a metal salts to CA to EG mole ratio of 1:3:16. The resulting electrode surface had a complete mesh pit structure after calcination at 550 degrees C. Several key factors were found to affect the degradation of dissolved organic carbon (DOC), including current density, chloride ion concentration, Fe (II) concentration, and acidity. The presence of chloride ions on the anode surface significantly improved the conversion efficiency of hydroxyl radicals, which played a crucial role in the oxidation of the organics. Additionally, near the cathode, oxidative radicals such as H2O2 and O-2(-)center dot were generated, while hydroxyl radicals were produced with the addition of Fe (II) and H+. Under a current density of 20 mA center dot cm(-2), the Ti/SnO2-Sb anode achieved a COD removal rate of 94.5% and a DOC removal rate of 43.4%.