A novel filtration composite anode configuration of microbial fuel cell for efficient wastewater treatment and enhanced power generation

Abstract

Abstract A microbial fuel cell (MFC), as a cleaner wastewater treatment process, can recover electricity from organic wastes. However, high power production and high quality effluent are difficult to achieve simultaneously. In this study, a novel filtration composite anode (FCA), which combined carbon fiber brush and carbon textile was proposed to enhance COD removal and power generation performance of MFCs. The COD removal rate constant of MFCs with the filtration composite anode (FCA-MFC) was 0.33 h−1, much higher than that of MFCs with single brush anode (FB-MFC) (0.23 h−1) or textile anode (FT-MFC) (0.18 h−1) in the recirculation mode, and also exceeded that of CA-MFC in non-recirculation mode (0.12 h−1). FCA-MFC delivered a maximum power density of 1140 mW m−2 at a recirculation rate of 2 mL min−1, which was higher than the FB-MFC (990 mW m−2) and the FT-MFC (80 mW m−2) and its counterparts in non-recirculation mode (1000 mW m−2). Moreover, the FCA-MFC maintained a higher current density (4.0 A m−2) than the other two MFCs until the COD decreased to 40 mg L−1 at an external resistance of 100 Ω. CV and EIS tests verified a higher electrochemical performance of the filtration composite anode. These results demonstrated higher COD removals and power generation of the composite anode at ambient temperature, resulting from the filtration effect that facilitated mass transfer, increased microbial colonization, and improved electrochemical activity. Considering the high-quality effluent and high power generation, the filtration composite anode configuration promises a great potential for sustainable wastewater treatment application.