Enhanced performance of microbial fuel cell with polyaniline/sodium alginate/carbon brush hydrogel bioanode and removal of COD

Abstract The use of capacitive and biocompatible anode materials is important for constructing microbial fuel cells (MFCs). Here, self-supporting polyaniline-sodium alginate/carbon brush (PANI-SA/CB) hydrogel was prepared by in situ polymerization as an MFC anode. The easily fabricated PANI–SA-conducting hydrogels showed great potential as electrode materials for MFC anodes. The maximum power density of MFCs equipped with PANI-SA/CB hydrogel bioanodes was 515 mW/m2, which was 1.38 times higher than that of the blank CB bioanode (373 mW/m2). During the charging-discharging experiment with 30 min of charging and 60 min of discharging, the stored charge Qs of the PANI-SA/CB hydrogel bioanode was 1984.42C/m2, 2.98 times higher than that of the blank CB bioanode (665.88C/m2). The robustness of our findings stems from the excellent capacitive properties of PANI-SA. These findings suggest that anode materials, such as the PANI-SA/CB hydrogel anode in MFCs, can function as biocapacitors, as they can simultaneously store electrons generated from microbial oxidation of substrates and release the accumulated charge.