Cathodic Electron Acceptor Governs Energy Recovery and Methylene Blue Dye Decolorization in Microbial Fuel Cells

This study focused on a comparative analysis of oxygen and hypochlorite ions as cathodic electron acceptors in microbial fuel cell (MFC) reactors treating wastewater containing methylene blue dye. One of the major factors influencing MFC performance is the choice of cathodic electron acceptor, which directly affects electrochemical efficiency and treatment performance. Based on the analysis, the hypochlorite ion-assisted MFC (MFC-H) performed better in its electrochemical properties, achieving a maximum power density of 115.2 mW m−2, which was much higher than that of the oxygen-cathode MFC (29.44 mW m−2). The MFC-H system also exhibited higher coulombic efficiency, a more positive cathode potential, and greater decolorization efficiency (88%) compared to the oxygen-cathode configuration (79%). The enhanced performance of the hypochlorite-based system indicates more effective electron transfer and faster cathodic reaction kinetics, thereby improving energy recovery and dye removal. These results demonstrate that hypochlorite can serve as an effective alternative cathodic electron acceptor in MFCs for treating dye-containing wastewater.