Cathodic Reduction of Cu2+

Abstract

When <TEX>$Cu^{2+}$</TEX> was used as an electron acceptor, removal of <TEX>$Cu^{2+}$</TEX> was achieved from the synthesized wastewater (SW) in the cathode compartment of a microbial fuel cell (MFC). By addition of <TEX>$KNO_3$</TEX>, the different initial pH of the SW showed no effect on the removal efficiency of <TEX>$Cu^{2+}$</TEX>. For <TEX>$Cu^{2+}$</TEX> concentration of 50 mg/L the removal efficiencies were found to be 99.82%, 99.95%, 99.58%, and 99.97% for the <TEX>$KNO_3$</TEX> 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% <TEX>$Cu^{2+}$</TEX> was removed for the <TEX>$Cu^{2+}$</TEX> concentrations of 10, 50, and 100 mg/L, while only 60.1% of <TEX>$Cu^{2+}$</TEX> was removed for the initial concentration of 200 mg/L (pH 3). The maximum power density was affected by both <TEX>$KNO_3$</TEX> concentration and initial concentration of <TEX>$Cu^{2+}$</TEX>. It was increased by a factor of 1.5 (from 96.2 to 143.6 mW/<TEX>$m^2$</TEX>) when the <TEX>$KNO_3$</TEX> concentration was increased from 0 to 200 mM (50 mg/L <TEX>$Cu^{2+}$</TEX>), and by a factor of 2.7 (from 118 to 319 mW/<TEX>$m^2$</TEX>) when <TEX>$Cu^{2+}$</TEX> concentration was increased from 10 to 200 mg/L (pH 3).