Cathodic Reduction of Cu2+

Abstract

When Cu2+ was used as an electron acceptor, removal of Cu 2+ was achieved from the synthesized wastewater (SW) in the cathode compartment of a microbial fuel cell (MFC). By addition of KNO3, the different initial pH of the SW showed no effect on the removal efficiency of Cu2+. For Cu2+ concentration of 50 mg/L the removal efficiencies were found to be 99.82%, 99.95%, 99.58%, and 99.97% for the KNO3 concentrations of 0, 50, 100 and 200 mM, and to be 99.4%, 99.9%, 99.7%, and 99.7% for pH values of 2, 3, 4, and 5, respectively. More than 99% Cu2+ was removed for the Cu2+ concentrations of 10, 50, and 100 mg/L, while only 60.1% of Cu2+ was removed for the initial concentration of 200 mg/L (pH 3). The maximum power density was affected by both KNO3 concentration and initial concentration of Cu2+. It was increased by a factor of 1.5 (from 96.2 to 143.6 mW/m2) when the KNO3 concentration was increased from 0 to 200 mM (50 mg/L Cu 2+), and by a factor of 2.7 (from 118 to 319 mW/m2) when Cu2+ concentration was increased from 10 to 200 mg/L (pH 3).