Unlocking the applicability of Ni-based self-supported anodes in microbial fuel cells for the shale gas flowback wastewater treatment

The NiCo₂O₄ (NCOC) and Ni-P (NPC) self-supported anodes were successfully fabricated and utilized in microbial fuel cells (MFCs) for the treatment of actual shale gas flowback wastewater in this study. As a result, the NCOC and NPC displayed outstanding output voltages at 579.1 mV and 537.1 mV, as well as significantly decreased apparent internal resistances to 228.3 Ω and 396.7 Ω compared to the blank carbon cloth (CC, 206.7 mV and 1850.0 Ω). The electrochemical properties, rough surfaces and biocompatibility of NCOC (649.8 mW/m²) and NPC (436.1 mW/m²) endowed MFCs with superior power generation that was 11.7 and 7.8 times that of CC (55.7 mW/m²). Additionally, the removal ratios of the chemical oxygen demand based on NCOC and NPC achieved 61.5 % (1040.4 ± 34.1 mg/L) and 67.2 % (1136.7 ± 34.1 mg/L) with the increased energy conversion ratios from 8.4 % to 11.2 % and 9.7 %. Ultimately, the successful formation of the biofilms and the enrichment of the functional microorganisms such as Marinobacterium, Halomonas and Desulfuromonas on the prepared anodes further verified that NCOC and NPC could be potential research candidates in MFCs for decontaminating high-salty industrial wastewater.