Continuous removal of heavy metals by coupling a microbial fuel cell and a microbial electrolytic cell
Guo R. Xie,Chan S. Choi,Bong S. Lim,Shao X. Chu
Abstract
This work aims at studying the feasibility of continuous removal of mixed heavy metal ions from simulated zinc plating wastewaters by coupling a microbial fuel cell and a microbial electrolysis cell in batch and continuous modes. The discharging voltage of MFC increased initially from 0.4621 ± 0.0005 V to 0.4864 ± 0.0006 V as the initial concentration of Cr6+ increased from 10 ppm to 60 ppm. Almost complete removal of Cr6+ and low removal of Cu2+ occurred in MFC of the MFC-MEC-coupled system after 8 hours under the batch mode; removal efficiencies (REs) of Cr6+ and Cu2+ were 99.76% and 30.49%. After the same reaction time, REs of nickel and zinc ions were 55.15% and 76.21% in its MEC. Cu2+, Ni2+, and Zn2+ removal efficiencies of 54.98%, 30.63%, 55.04%, and 75.35% were achieved in the effluent within optimum HRT of 2 hours under the continuous mode. The incomplete removal of Cu2+, Ni2+ and Zn2+ ions in the effluent was due to the fact that the Cr6+ was almost completely consumed at the end of MFC reaction. After HRT of 12 hours, at the different sampling locations, Cr6+ and Cu2+ removal efficiencies in the cathodic chamber of MFC were 89.95% and 34.69%, respectively. 94.58%, 33.95%, 56.57%, and 75.76% were achieved for Cr6+, Cu2+, Ni2+ and Zn2+ in the cathodic chamber of MEC. It can be concluded that those metal ions can be removed completely by repeatedly passing high concentration of Cr6+ through the cathode chamber of MFC of the MFC-MEC-coupled system.
Key Words
microbial fuel cell; microbial electrolytic cell; removal of mixed heavy metal ions; removal efficiency; hydraulic retention time; wastewater treatment
Address
Guo R. Xie, Chan S. Choi — Department of Applied Chemistry, Daejeon University, 62 Daehak-ro, Dong-gu, Daejeon, 34520, Republic of Korea
Bong S. Lim and Shao X. Chu — Department of Environmental Engineering, Daejeon University, 62 Daehak-ro, Dong-gu, Daejeon, 34520, Republic of Korea
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