Removal of Cyanide by Electrocoagulation Process

Free cyanide and its related compounds are the most known contaminants which are released from industrial effluents to the environment; the objective of this study was to evaluate the efficiency electrocoagulation reactor with iron plate in order to find optimum operational conditions for cyanide removal from cyanide-containing effluents. The reactor was tested under different operational conditions of voltage (20, 30, and 40 V), detention time (20, 30, 40, 60, and 90 min), and influent concentration (20, 30 40, and 50 mg/l). Since ferrous ion capability to react with free cyanide and its related compounds are (97%) well established, iron plate was used as electrode in the present study. Additionally, to prevent creating ferric ion and ferric hydroxide precipitates in the reactor which decrease the removal efficiency, bisulfite was applied to hold ferrous ion in the reactor. The optimum operational conditions were obtained after running the reactor for several times. Based on the results, the optimum removal efficiency was obtained at voltage of 40 V, detention time of 90 min, and influent concentration of 50 mg/l. Therefore, this process may be considered as an alternative method for the removal of cyanide from cyanide- containing wastewaters.