Facilitated Cr(VI) removal in waste water by microbial fuel cell through promoting electron transfer: Effect of...

A porous carbon modified carbon paper electrode microbial fuel cells (MFCs) system was designed to remediate chromium (Cr)-contaminated water. The electro catalyst derived from sawdust was prepared by one-step pyrolysis method. The electron transfer resistance of pyrolysis sawdust-derived modified porous carbon paper (SD-CP) was 484.92 Ω-significantly lower to the control group with carbon paper (CP, 1023.12 Ω). The power generation of MFCs equipped with SD-CP with different hexavalent chromium [Cr(VI)] concentrations (1000 mg L^-1, 750 mg L^-1, 500 mg L^-1, 200 mg L^-1, and 50 mg L^-1) was accordingly higher than that of MFCs with CP. The Cr(VI) removal rate was 99.32% after treatment by MFCs with SD-CP for 33 h, whereas that of the MFCs with CP was 98.53% after 57 h. The Cr(VI) in MFCs with SD-CP at different Cr(VI) concentrations was nearly completely removed, suggesting that SD-CP could be used for a wide range of Cr(VI) concentration. Moreover, the scanning electron microscopy of the catalyst materials and cyclic voltammetry curve of SD-CP confirmed the formation of a macroporous structure and the improvement of the electrochemically active area, resulting in the promotion of the electrochemical activity of the cathode. The electrochemical and physical-chemical characterization and bacterial diversity illustrated that sawdust porous carbon is a remarkable and environmentally harmless electrochemical catalyst for facilitating Cr(VI) removal and power generation by promoting the transfer of electrons.