Efficient treatment of high-concentration sulfurous wastewater by using electrochemical oxidation process with Ti/SnO2-Sb anode and air cathode

High-concentration sulfurous wastewater is biologically toxic, corrosive, harmful to environment and human health, highly required to be separately treated. In this paper, an air-cathode electrochemical oxidation process (EO) was investigated to treat high-concentration sulfurous wastewater from coal chemistry industry. The effectiveness was evaluated by chemical oxygen demand (COD) removal, color (ADMI) removal, and total organic carbon (TOC) removal. The results showed that 99.1% COD, 100% color, and 94.5% TOC were removed by EO at the applied current of 40 mA cm(-2) for 24 h. The COD removal accords with zero-order kinetics with a constant of 2598.3 mg L-1 h(-1), while the TOC removal follows the first-order kinetics with a constant of 0.1128 h(-1). The highest current efficiency of 94.3 +/- 0.6% and the lowest energy consumption of 9.4 +/- 0.1 kWh kg COD-1 were achieved when removing 98% of COD at the current density of 40 mA cm(-2). The results indicate that the air-cathode electrochemical oxidation process is feasible to efficiently treat high-concentration sulfurous wastewater.