Oxidation of Cyanide and Simultaneous Copper Electrodeposition from Electroplating Wastewater in an Electrochemical Reactor

Copper was widely used in electroplating, and a lot of wastewater was produced in the rinsing process. Copper-containing electroplating wastewater can be divided into cyanide wastewater and copper sulfate wastewater according to the difference of plating process. This study is to explore the feasibility of cyanide oxidation and cupric reduction in an electrochemical reactor using an anion exchange membrane as the diaphragm. In the anolyte compartment cyanide in the cyanide wastewater was oxidized to cyanate, and furthermore, to carbon dioxide and nitrogen. In the catholyte compartment cupric in the copper sulphate wastewater was restored to copper. This study showed that the dosage of sodium hypochlorite used in the cyanide oxidation was decreased from 95 to 15 g/L and over 80% copper was recovered from copper sulphate wastewater by electrolysis.