Removal of thiocyanates and heavy metal ions from simulated wastewater solutions by electro- and peroxyelectrocoagulation

Abstract

A procedure for treatment of simulated wastewater solutions to remove Cu²⁺, Ni²⁺, and SCN⁻ ions using various combinations of aluminum and iron electrodes in the electro- and peroxyelectrocoagulation processes was studied. The influence exerted by the current density, pH of solution, and concentrations of impurities and hydrogen peroxide on the efficiency of removal of these ions was analyzed. Electrocoagulation using aluminum anode does not lead to a significant decrease in the thiocyanate concentration. In the peroxyelectrocoagulation process, the efficiency of removal of SCN− ions increases with an increase in the [H₂O₂]: [SCN⁻] ratio. The electrocoagulation efficiency with the Fe/Fe electrode pair reaches 87% for SCN⁻ and 99.5% for Cu²⁺ and Ni²⁺ at a current density of 20 mA cm^–2 and electrolysis time of 20 min.