Recent advances in design optimization and scale‐up perspectives of microbial fuel cells for sustainable wastewater treatment and bioenergy recovery

Abstract

Microbial fuel cells (MFCs) are bioelectrochemical systems that enable simultaneous wastewater treatment and bioenergy recovery through microbial oxidation of organic substrates. Despite considerable progress in reactor design, electrode materials, membrane development, and electrochemical characterization, practical implementation remains limited by low power density, high internal resistance, membrane fouling, electrode cost, microbial instability, and scale‐up challenges. This review critically evaluates major MFC configurations, including single‐chamber, double‐chamber, stacked, sediment, plant, and benthic systems, together with the influence of substrates, electroactive microorganisms, electrodes, proton‐exchange membranes, and external circuits on overall performance. Representative studies reviewed herein reported power densities of 222.34 mW/m ² for a food‐industry‐wastewater DCMFC and 0.593 W/m ³ for an activated‐sludge‐based system, illustrating the strong dependence of performance on reactor configuration and normalization basis. Pollutant‐removal studies further demonstrated 80% COD reduction alongside 84% degradation of 1,2‐propanediol, while toxic‐metal removal efficiencies reached >90% for several metals and up to 99.3% for Ag in selected systems. The review further examines polarization analysis, electrochemical impedance spectroscopy, and cyclic voltammetry as tools for assessing electron‐transfer and resistance limitations. Overall, the evidence indicates that electrode–biofilm interactions, substrate characteristics, membrane transport, internal resistance, and electrical loading jointly control MFC performance.