Synergistic performance of nickel-based anode microbial fuel cells for the treatment of shale gas flowback wastewater and aged landfill leachate.

NiCo2O4-modified carbon cloth (NCOC) and Ni-P-coated carbon cloth (NPC) were prepared as Ni-based anodes for microbial fuel cells (MFCs), which treat mixed wastewater composed of equal volumes of shale gas flowback wastewater (SGFW) and aged landfill leachate (ALL). The NPC anode MFC (NPC-MFC) achieved the highest output voltage of 643.3 mV and a maximum power density of 1412.9 mW m-2, with a markedly lower apparent internal resistance of 155 Ω than the NCOC-MFC (398.2 mV, 196.2 mW m-2 and 870.0 Ω). Moreover, the electrochemical measurements showed that the NPC anode exhibited a much higher exchange current density (26.7 times that of CC). The NPC-MFC exhibited a higher coulombic efficiency (CE), while its chemical oxygen demand (COD) removal of 931.9 ± 34.6 mg L-1 was slightly lower than that of NCOC-MFC (1103.4 ± 69.3 mg L-1), which may be attributed to competition among dominant microbial species. Furthermore, the favorable biofilm morphology and the high abundance (97.4%) of dominant electroactive bacteria further suggested the potential of the NPC electrode for treating mixed wastewater. This study demonstrates the advantage of the NPC anode under mixed wastewater and suggests an electrode-dependent co-treatment benefit, providing useful insights for treating ALL and SGFW in future applications.