Electrochemical degradation of chloroform using Ti/IrO₂ anode and Cu/Zn cathode

Electrochemical method is a promising technology for biorefractory organic wastewater treatment. In this study, commercial available electrode materials, Ti=IrO₂ and Cu/Zn, were used as anode and cathode, respectively, to treat CHCl₃-contaminated water. The performance was investigated through cyclic voltammetry and paired electrolysis in an undivided cell. The voltammetric data revealed that the Cu/Zn cathode exhibited good electrocatalytic activity toward CHCl₃ reduction. By contrast, no direct oxidation of CHCl₃ was observed at the Ti=IrO₂ anode. The reduction of CHCl₃ at the Cu/Zn cathode took place through a three-step consecutive hydrodechlorination mechanism. During the paired electrolysis with current density of 15 mA=cm2, the chemical oxygen demand (COD) of CHCl₃ solution was decreased from 194 to 74 mg=L within 300 min with an energy consumption of 28.6 kWh · L−1. A mild acidic environment (pH 4.6) was shown to be more favorable to CHCl₃ abatement. Decreasing the anode/cathode surface area ratio also had significant impact on CHCl3 reduction, and the optimal ratio was 2.0. The results demonstrated that Cu/Zn cathode is a potential candidate for chlorinated organic compound removal.