Selective recovery of Cu2+ and Ni2+ 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 Cu2+ and Ni2+ ions from wastewater. The wastewater was treated in the cathode chambers of the system, in which Cu2+ and Ni2+ ions were removed by using the MFC and the MEC, respectively. At an initial Cu2+ concentration of 500 mg.L-1, removal efficiencies of Cu2+ increased from 97.0%+/- 1.8% to 99.0%+/- 0.3% with the initial Ni2+ concentrations from 250 to 1000 mg.L-1, and maximum power densities increased from 3.1 +/- 0.5 to 5.4 +/- 0.6 W.m(-3). The Ni2+ removal mass in the MEC increased from 6.8 +/- 0.2 to 20.5 +/- 1.5 mg with the increase of Ni2+ concentrations. At an initial Ni2+ concentration of 500 mg.L-1, Cu2+ removal efficiencies decreased from 99.1%+/- 0.3% to 74.2%+/- 3.8% with the initial Cu2+ concentrations from 250 to 1000 mg.L-1, and maximum power densities increased from 3.0 +/- 0.1 to 6.3 +/- 1.2 W.m(-3). Subsequently, the Ni2+ removal efficiencies decreased from 96.9%+/- 3.1% to 73.3%+/- 5.4%. The results clearly demonstrated the feasibility of selective recovery of Cu2+ and Ni2+ from the wastewater using the bioelectrochemical system.