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As a viable wastewater treatment and energy recovery technology, microbial fuel cell (MFC) requires more research with regard to the simultaneous achievement of high-quality effluent and high power generation. In this study, a novel flow-through carbon-based composite anode configuration is proposed, which combines the carbon cloth of two-dimensional anode with wooden granular activated carbon of three-dimensional anode. The proposed configuration enhances the performance of power production and chemical oxygen demand degradation by promoting the mass transfer, reducing internal resistance and increasing bioburden. Microbial fuel cell with the composite anode exhibited the highest maximum power density (1300 ± 50 mW m−2) and the highest chemical oxygen demand removal rate constant (0.155 ± 0.007 h−1) compared with the microbial fuel cell using the carbon cloth anode (1136 ± 46 mW m−2 and 0.072 ± 0.008 h−1) or the wooden granular activated carbon anode (1045 ± 32 mW m−2 and 0.129 ± 0.009 h−1). Meanwhile, at a lower chemical oxygen demand concentration (about 48 mg L−1), the microbial fuel cell with the composite anode maintained a current density of 2.4 A m−2, which is 18% higher than the wooden granular activated carbon anode (2.04 A m−2) and 400% higher than the carbon cloth anode (0.48 A m−2). The cyclic voltammetry and electrochemical impedance spectroscopy tests confirmed that the composite anodes displayed better electrochemical performance. Improving the flow rate and reducing the external resistance could effectively enhance the power production and chemical oxygen demand removal performance of microbial fuel cells, while the computational fluid dynamics simulation intuitively demonstrated the positive effect of the composite anode on chemical oxygen demand degradation. These results suggest that the flow-through composite anode provides a feasible strategy to simultaneously enhance the power generation and improve the effluent quality. Image 1 • A composite anode was constructed by optimizing 2D and 3D carbon anode materials.. • Flow-through composite anode MFC had higher power generation and COD removal rate. • Flow-through composite anode MFC maintained high power generation at low COD. • Reducing external resistance and improving flow rate enhanced the MFC performance. • Flow-through composite anode MFC was proved better COD removal in CFD simulation. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]