Simultaneous Cr(VI) reduction and bioelectricity generation in a dual chamber microbial fuel cell

Abstract

Microbial fuel cells (MFCs) technology for treating wastewater containing Cr(VI) and generating bioelectricity simultaneously at an abiotic cathode by utilizing the electricigens on the biotic anode, have been run. In this work, the Cr(VI) is bio-electrochemically reduced to nontoxic Cr(III) in the dual chamber MFCs with different cathodes. The 80 mg L−1 of Cr(VI) is completely removed by MFC with carbon cloth cathode, and the MFC exhibits higher power density than that of these MFC with carbon brush cathode and carbon felt cathode. Besides, the linear sweep voltammetry (LSV) of carbon cloth cathode demonstrates that the electrochemical performance increases with the increase of the initial Cr(VI) concentration. The MFC achieves the maximum power density of 1221.94 mW m−2 in the catholyte contained 120 mg L−1 of Cr(VI), and the power density is great higher than the MFC with the catholyte contained 50 mg L−1 or 80 mg L−1 of Cr(VI). Meanwhile, the 100% Cr(VI) is totally removed by the electrochemical reduction of Cr2O72− to Cr(OH)3 on the surface of carbon cloth cathode. The present study has successfully verified that a promising MFC technology can achieve high output power in removing Cr(VI), revealing the enormous potential of scale-up MFCs for heavy metal treatment.