title: Cadmium recovery by coupling double microbial fuel cells.
abstract: Cr(VI)-MFC of the double microbial fuel cell (d-MFC) arrangement could successfully complement the insufficient voltage and power needed to recover cadmium metal from Cd(II)-MFC, which operated as a redox-flow battery. It was also possible to drain electrical energy from the d-MFC by an additional passage. The highest maximum utilization power density (22.5Wm(-2)) of Cr(VI)-MFC, with the cathode optimized with sulfate buffer, was 11.3times higher than the highest power density directly supplied to Cd(II)-MFC (2.0Wm(-2)). Cr(VI)-MFC could generate 3times higher power with the additional passage than without it; and the current density for the former was 4.2times higher than the latter at the same maximum power point (38.0Am(-2) vs. 9.0Am(-2)). This boosting phenomenon could be explained by the Le Chatelier's principle, which addresses the rate of electron-hole pair formation that can be accelerated by quickly removing electrons generated by microorganisms.
authors.affiliation: Department of Applied Chemistry, Daejeon University, 62 Daehak-ro, Dong-gu, Daejeon 300-716, Republic of Korea. Electronic address: cse110@dju.ac.kr.
authors.forename: Chansoo
authors.initials: C
authors.lastname: Choi
authors.affiliation: Department of Applied Chemistry, Daejeon University, 62 Daehak-ro, Dong-gu, Daejeon 300-716, Republic of Korea.
authors.forename: Naixu
authors.initials: N
authors.lastname: Hu
authors.affiliation: Department of Environmental Engineering, Daejeon University, 62 Daehak-ro, Dong-gu, Daejeon 300-716, Republic of Korea.
authors.forename: Bongsu
authors.initials: B
authors.lastname: Lim
mesh_terms: D001674:Bioelectric Energy Sources; D002104:Cadmium / Q000302:isolation & purification*; D055664:Electrochemical Techniques / Q000379:methods*; D008956:Models, Chemical; D010084:Oxidation-Reduction; D014874:Water Pollutants, Chemical / Q000302:isolation & purification*; D018508:Water Purification / Q000379:methods*
chemical_list: D014874:Water Pollutants, Chemical; D002104:Cadmium
keywords: Charge transfer resistance; Double microbial fuel cell arrangement; Le Chatelier’s principle; Power boosting effects; Redox-flow battery