Electrochemical Removal Cyanide in Wastewater by Ti/RuO₂-Pt Electrodes

Abstract

A laboratory-scale electrolytic cell with a Ti/RuO2-Pt anode and a Ti cathode was developed to treat high concentration cyanide-contained wastewater. The effects of the different electrode distances, concentration of chlorine anion and current densities, on the CN- removal were investigated. The results shown the too short and long electrode distance resulted in high energy consumption and low current, the appropriate electrode distance was essential. The CN- removal was very significant at the electrode distance was 9 cm, and the removal efficiency reached 99.2%. The removal CN- electrochemical oxidation was mainly attributed the success to in direct oxidation effect of chlorine /hypo-chlorite produced during the electrochemical reaction process. The CN- removal efficiency increased with increasing the concentration of chloride ion and operating current density. The optimum experimental condition was set at the electrode distance of 9 cm, NaCl dosage of 0.5 g/L, the current density of 10 mA/cm2, and pH of 12. At the optimum experimental condition, the CN- concentration in the solution decreased from 150.33 mg/L to 1.20 mg/L, and the CN- removal efficiency reached 99.2%.