Zhang Jingran, Sun Yilun, Zhang Haochi, Cao Xian, Wang Hui, Li Xianning
School of Energy and Environment, Southeast University, Nanjing, 210096, China.
School of Energy and Environment, Southeast University, Nanjing, 210096, China; Department of Civil and Environmental Engineering, Graduate School of Engineering, Tohoku University, Aoba Aramaki 6-6-06, Sendai, 980-8579, Japan.
Environ Res. 2021 Jul;198:111217. doi: 10.1016/j.envres.2021.111217. Epub 2021 May 8.
Microbial fuel cells (MFCs) with different electrode configurations were constructed to study the mechanism of influence of multiple current paths on their electrical performance and the removal of heavy metals in soil. Three types of MFCs were constructed, namely, double anode-single cathode (DASC), single anode-dual cathode (SADC), and single anode-single cathode (SASC). The total electricity generation of the three kinds of MFC was similar: 143.44 × 10-3 mW, 114.90 × 10-3 mW, and 132.50 × 10-3 mW, respectively. However, the maximum voltage and cathode current density produced by a single current path differed significantly. The corresponding values were 0.27, 0.23, and 0.42 V and 0.130, 0.122, and 0.096 A/m 2, respectively. The SASC had the best electricity generation performance. Based on a limited reduction rate of oxygen at the cathode, the accumulation of cathode electrons was facilitated by the construction of multiple current paths in the MFC, which significantly increased the cathode electron transfer resistance and limited the electricity generation performance of the MFC. However, at the same time, the construction of multiple current paths promoted output of more electrons in the anode, reducing the retention of anode electrons and anode electron transfer resistance. The heavy metal removal efficiencies of SASC, DASC, and SADC were 2.68, 2.18, and 1.70 times that of the open circuit group, respectively. The migration of heavy metals in the soil depended mainly on the internal electric field intensity of the MFC rather than the total electricity generation. As the internal electric field intensity increased, the removal efficiency of heavy metals in the MFC increased.
构建了具有不同电极配置的微生物燃料电池（MFC），以研究多电流路径对其电性能的影响机制以及土壤中重金属的去除情况。构建了三种类型的MFC，即双阳极 - 单阴极（DASC）、单阳极 - 双阴极（SADC）和单阳极 - 单阴极（SASC）。三种MFC的总发电量相似，分别为143.44×10⁻³mW、114.90×10⁻³mW和132.50×10⁻³mW。然而，单电流路径产生的最大电压和阴极电流密度差异显著。相应的值分别为0.27、0.23和0.42V以及0.130、0.122和0.096A/m²。SASC具有最佳的发电性能。基于阴极处有限的氧还原速率，MFC中多电流路径的构建促进了阴极电子的积累，这显著增加了阴极电子转移电阻并限制了MFC的发电性能。然而，与此同时，多电流路径的构建促进了阳极中更多电子的输出，降低了阳极电子的保留和阳极电子转移电阻。SASC、DASC和SADC的重金属去除效率分别是开路组的2.68、2.18和1.70倍。土壤中重金属的迁移主要取决于MFC的内部电场强度而非总发电量。随着内部电场强度的增加，MFC中重金属的去除效率提高。
