Nickel-doped porous carbon anode microbial fuel cell to enhance the performance in wastewater treatment

Abstract

The choice of anode material is crucial in determining the performance of microbial fuel cells (MFCs). In the current study, a novel nickel-doped coal-based porous carbon (CPC-N) is prepared by the metal doping method. CPC-N exhibits improvements in specific surface area (2042.5 m²/g), electrical conductivity (the apparent internal resistance is only 202.6 Ω), graphitization (the d₀₀₂ is 0.359), biocompatibility, and catalytic properties (the maximum current density can reach 21.2 A/m², 6.4 times than CC). The CPC-N anode demonstrates superior power production in a dual-chamber microbial fuel cell treating mixed wastewater of shale gas flowback wastewater (SGFW) and aging landfill leachate (LFL) with a maximum stabilized output voltage of 633.4 mV and a maximum power density of 1129.7 mW/m². Meanwhile, the CPC-N anode also achieves degradation rates of 48.5 ± 2.1 % for chemical oxygen demand (COD) and 61.0 ± 1.4 % for ammonia nitrogen (NH₃−N), showcasing its effectiveness in pollutant removal. Electrochemical tests show that CPC-N anodes significantly reduced the charge transfer resistance, and improved the exchange current density and capacitance performance. Community analysis shows that nickel doping could enhance the diversity and evenness of anode microorganisms. Moreover, the relative abundance of Desulfobacterota, Bacteroidota, Firmicutes, and Proteobacteria at the phylum level, while Desulfuromonas and Lentimicrobium at the genus level are comparatively higher on the CPC-N anode. These findings offer an exciting avenue for improving the performance of carbon-based-anode MFC.