Enhanced treatment of aged landfill leachate and bioelectrochemical performance in microbial fuel cells with layered double hydroxide anodes: A systematic comparative study

Given the limited comparative understanding of LDH-based anodes in MFCs, NiCo-LDH, NiMn-LDH, and CoMn-LDH were fabricated on carbon cloth by potentiostatic electrodeposition. Loading LDHs significantly enhanced the specific surface area, graphitization degree, and electrochemical activity. The Ni-rich NML anode exhibited a rough spherical morphology, the highest redox activity (specific capacitance 3.174 F/cm 2 , exchange current density 3.03 × 10 −1 mA/cm 2 ), and in treating aged landfill leachate, the lowest internal resistance (301.7 Ω), achieving a maximum output voltage of 579.8 mV and maximum power density of 771.2 mW/m 2 (8.22 times that of bare carbon cloth). COD and NH 3 -N removal reached respectively 78.4% ± 0.9% and 64.7% ± 0.3%. Phylum-level analysis revealed a denser biofilm enriched in Pseudomonadota and Thermodesulfobacteriota (38.55%), enhancing synergistic pollutant degradation and electricity generation. The NML anode was associated with a higher relative abundance of Desulfuromonas (11.38%), a genus known for extracellular electron transfer; this enrichment may contribute to an efficient electroactive biofilm and potentially provide a microbiological foundation for simultaneous pollutant removal and energy recovery. This study provides a systematic comparison of three bimetallic LDH anodes and demonstrates that their metal composition and surface morphology are closely associated with electrochemical behavior, biofilm development, and microbial community structure. The results provide mechanistic insights into the material–microbiome–performance relationships of LDH-based anodes for bioelectrochemical treatment of aged landfill leachate.