Effect of NiCo2O4 and Ni-P modified anodes on the treatment of aging landfill leachate by microbial fuel cells

NiCo2O4 modified carbon cloth (CC) and Ni-P modified CC are respectively prepared and used as microbial fuel cell (MFC) anodes to deal with the aging landfill leachate. The electrode characterization results reveal a significant improvement in redox activity, owing to the large specific capacitance and excellent electrochemical activity. The MFCs using NCOC and NPC anodes severally exhibit excellent power production performance with the maximum steady-state output voltages of 598.0 mV and 483.0 mV and maximum power densities of 502.9 mW/m2 and 383.4 mW/m2, which are better than that of CC electrode (216.8 mV, 212.4 mW/m2). Moreover, the electrochemical measurements of MFCs unveil that the modified electrodes have significantly higher exchange current densities (9.8 times than that of CC) and lower internal resistances (about 1/5 of CC). As far as chemical oxygen demand (COD) removal and the coulombic efficiency (CE) are concerned, the COD removal of NCOC and NPC are 880.9 ± 34.6 mg/L and 917.7 ± 17.3 mg/L, and their CEs are 13.9 ± 0.5% and 17.8 ± 0.3%, respectively. According to the analysis of biofilms and microbial communities, the selective effect of electrode materials on the dominant bacteria Desulfobacterota, Proteobacteria makes NiCo2O4 and Ni-P possess considerable prospects as modified materials for MFC anodes.