Biomass-derived 3D hydrogel bioanode forincreasing electron transfer and chemical oxygen demand removal efficiency

Microbial fuel cells (MFCs) have garnered significant attention in power generation and wastewater treatment fields. Current MFCs have relatively low power density due to limited biofilm colonization and sluggish extracellular electron transfer (EET) processes. Here, a hybrid hydrogel (PPy-CMC-MXene) was prepared by doping MXene with an inexpensive and readily available biomass source carboxymethyl cellulose (CMC) and polypyrrole (PPy). The MFC equipped with PPy-CMC-MXene/CC anode has more than twice the power density, more than 30 times the specific capacitance, nearly 30 times the electron transfer efficiency, and 4.8 times the coulombic efficiency compared with the original carbon fiber cloth (CC) anode. More notably, the MFC equipped with the PPy-CMC-MXene/CC anode had an excellent chemical oxygen demand (COD) removal efficiency of 89.2%. It was shown that the PPy-CMC-MXene/CC electrode offered good biocompatibility and was beneficial to the enrichment of Proteobacteria and Acinetobacter. The anode material has some application prospects in water treatment and the adsorption of electricity-producing bacteria.