Cadmium, Cyanide and Cadmium-Cyanide Removal from Wastewater Solutions by Electrocoagulation Process

Abstract

Treatment of cadmium (Cd), cyanide (CN) and cadmium-cyanide (Cd-CN) wastewater solutions by electrocoagulation (EC) using iron electrodes have been investigated in this research. CN and Cd removals at current density of 30 A/m2 and EC time of 50 min from Cd-CN containing wastewaters were 99.70 and 99.52%, respectively; and 2.1746 $/m3 at operation cost at these EC conditions. EC gives CN removal efficiency of 99.81% and 2.5978 $/m3 operation cost for wastewater contaminated only by CN with 30 A/ m2 and 50 min of process time. For wastewaters contaminated only by Cd, 99.8% removal efficiency, with 2.052 $/m3 operation cost under the same current density and process time. Approximately the same high removal efficiencies were achieved for each of the wastewater (Cd-CN, CN, Cd) used in the experiments. The highest removal efficiency of CN was achieved at pH 8.6 for wastewaters contaminated by CN or CN-Cd whereas the highest Cd removal efficiency was obtained at pH 10.6 for wastewaters contaminated by Cd. As a result, EC process gives quite high removal efficincies of Cd and CN for wastewaters coming from metal plating rinse baths.