Copper Recovery Combined with Electricity Production in a Microbial Fuel Cell

A metallurgical microbial fuel cell (MFC) is an attractive alternative for recovery of copper from copper containing waste streams, as the metal is recovered in its metallic form at the cathode, while the energy for metal reduction can be obtained from oxidation of organic materials at the anode with possible additional production of electricity. We studied the recovery of copper in an MFC using a bipolar membrane as a pH separator. Under anaerobic conditions, the maximum power density was 0.43 W/m2 at a current density of 1.7 A/m2. In the presence of oxygen, MFC performance improved considerably to a maximum power density of 0.80 W/m2 at a current density of 3.2 A/m2. Pure copper crystals were formed on the cathode, and no CuO or Cu2O was detected. Removal efficiencies of >99.88% were obtained. The cathodic recovery of copper compared to the produced electricity was 84% (anaerobic) and 43% (aerobic). The metallurgy MFC with the Cu2+ reducing cathode further enlarges the application range of MFCs.