Effect of Azolla Imbricata and Spirodela Polyrrhiza on Chromium(VI) Removal and Power Generation in a Plant Microbial Fuel Cell

In this study, we performed a remediation of hexavalent chromium-contaminated soil within a constructed plant microbial fuel cell and vary the voltage to study its power generation stability. The maximum power density was driven to investigate the performance of systematic electricity generation. Furthermore, the concentration changes in total chromium and hexavalent chromium in the reactor effluent were used to study the effect of Azolla imbricata on the hexavalent chromium removal rate. The results showed that the plant group was 40-80 mV higher when compared with the non-plant group. The maximum power density of the Azolla imbricata group was 2.14 times higher than that of the non-plant group, indicating that the electricity generation performance of the plant group was markedly improved. Compared to the non-plant group, the total chromium and hexavalent chromium residue are only 10.1% and 8.1%, respectively, in the Azolla imbricata group. The synergistic effect of plants and the microbial cell noticeably quickens the hexavalent chromium removal. This work provided a novel strategy for the treatment of hexavalent chromium-contaminated soil.