Enhancement of power generation by microbial fuel cells in treating toluene-contaminated groundwater: Developments of composite anodes with various compositions

This work develops microbial fuel cells (MFCs) with composite anodes that combine conductive coke (CC) and conductive carbon black (CCB) to improve the performance of those MFCs in treating toluene-contaminated groundwater. The effect of the combination ratio (CRCCB:CC) of the composite anode with various ratios of CCB to CC on MFC performance was evaluated. The results demonstrate that the time required (t(r)) for the MFC with CR1:3 to remove all toluene was half of that required by other MFCs except for that with CR1:9. Additionally, CR1:3 is associated with the highest power density (PDmax) of 72 mW/m(2), which is 1.24-2.78 times higher than those obtained using other CRs or a single-material anode (CC) except for CCB, owing to the high conductivity of the latter. Cyclic voltammetry (CV) yields oxidized-reduced current peaks of CR1:3 that are 1.44-2.89-fold as high as those obtained using other CRs, suggesting that the composite anode with CCB or CC at an optimal ratio accelerates the oxidation-reduction reactions, favoring the removal of organic waste. This work establishes the feasibility of using a composite anode to improve the removal of toluene and the generation of electricity by MFCs.