Article ID | Journal | Published Year | Pages | File Type |
---|---|---|---|---|
8850368 | Chemosphere | 2018 | 33 Pages |
Abstract
Cadmium(II) ion can affect the anode performance of bioelectrochemical systems (BES); however, how the presence of Cd2+ affect the extracellular electron transfer of anodic electrochemically active biofilms (EABs), the microbial viability and species composition of microorganism on the anode remain poorly understood. Here, we investigated the inhibitory effect of Cd2+ at different concentrations on the electrochemical performance and the biofilm community in mixed-culture enriched BES. The electrochemical performance of the BES was not inhibited at 2â¯mgâ¯Lâ1 Cd2+, while higher concentrations of 5-20â¯mgâ¯Lâ1 resulted in the decrease in the maximum power density, with 0.34â¯Â±â¯0.01â¯Wâ¯mâ2 at 5â¯mgâ¯Lâ1, 0.28â¯Â±â¯0.01â¯Wâ¯mâ2 at 10â¯mgâ¯Lâ1, and 0.17â¯Â±â¯0â¯Wâ¯mâ2 at 20â¯mgâ¯Lâ1, respectively. When adding 30â¯mg/L Cd2+, there was almost no power output. The decline of the power output was possibly ascribed to the suppressed viability and the change of species richness as evident from confocal laser scanning microscopy and microbial community analysis. Cyclic voltammogram and electrochemical impedance spectroscopy revealed that high concentration of Cd2+ exceeding 5â¯mgâ¯Lâ1 can inhibit the secretion of outer membrane cytochromes, thus reducing the electron transfer between the EABs and the anode surface. Analysis of bacterial structures showed a decrease in Geobacter accompanied by an increase in Stenotrophomonas and Azospira in response to Cd2+ at 10 and 20â¯mgâ¯Lâ1. This study added to the in-depth analysis of the inhibition of Cd2+ on EABs, and provided new insights into the removing Cd2+ and organics simultaneously in BES.
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Authors
Yaping Zhang, Jing Wen, Xi Chen, Guofu Huang, Yangao Xu, Yong Yuan, Jian Sun, Guanqun Li, Xun-an Ning, Xingwen Lu, Yujie Wang,