Selective recovery of Cu 2+ and Ni 2+ from wastewater using bioelectrochemical system

As the bioelectrochemical system, the microbial fuel cell (MFC) and the microbial electrolysis cell (MEC) were developed to selectively recover Cu 2+ and Ni 2+ ions from wastewater. The wastewater was treated in the cathode chambers of the system, in which Cu 2+ and Ni 2+ ions were removed by using the MFC and the MEC, respectively. At an initial Cu 2+ concentration of 500 mg ·L −1 , removal efficiencies of Cu 2+ increased from 97.0%± 1.8% to 99.0%±0.3% with the initial Ni 2+ concentrations from 250 to 1000 mg·L −1 , and maximum power densities increased from 3.1±0.5 to 5.4±0.6W·m −3 . The Ni 2+ removal mass in the MEC increased from 6.8±0.2 to 20.5±1.5 mg with the increase of Ni 2+ concentrations. At an initial Ni 2+ concentration of 500 mg·L −1 , Cu 2+ removal efficiencies decreased from 99.1%±0.3% to 74.2%±3.8% with the initial Cu 2+ concentrations from 250 to 1000 mg ·L −1 , and maximum power densities increased from 3.0±0.1 to 6.3±1.2W·m −3 . Subsequently, the Ni 2+ removal efficiencies decreased from 96.9%±3.1% to 73.3%±5.4%. The results clearly demonstrated the feasibility of selective recovery of Cu 2+ and Ni 2+ from the wastewater using the bioelectrochemical system.