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Membrane Water Treatment Volume 11, Number 4, July 2020 , pages 283-294 DOI: https://doi.org/10.12989/mwt.2020.11.4.283 |
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Continuous removal of heavy metals by coupling a microbial fuel cell and a microbial electrolytic cell |
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Guo R. Xie, Chan S. Choi, Bong S. Lim and Shao X. Chu
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| 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 | ||
