Enhanced oxygen reduction activity and high-quality effluent of membrane filtration electrodes with Prussian blue in microbial fuel cells

Membrane filtration electrode based microbial fuel cell provides a promising route to simultaneously recover energy and produce high-quality effluent during water treatment. Enhancing effluent quality and oxygen reduction reaction (ORR) activity of the membrane electrode still remains a major challenge. In this study, filtration types of membrane electrodes with Prussian blue (PB) doping and PVDF-PVC-PEG triblock copolymers were prepared by a simple phase inversion fabrication process. The PB-0.2 membrane electrode with optimal 0.2 wt% of PB obtained the highest current density (12.0 A m⁻²) and the lowest charge transfer resistance (5.0 ± 0.1 Ω). Rotating disk electrode (RDE) results also demonstrated that the PB-0.2 catalyst exhibited the superior ORR activity with the highest number of transferred electrons (n = 3.90). Furthermore, the MFC with PB-0.2 produced the maximum power density of 1401 ± 17 mW m⁻², which was 186.5% higher than that of the control. Moreover, the filtrated effluent tCOD_eff was 20.6 ± 1.2 mg L⁻¹ for the PB-0.2, which was significantly reduced by 63% compared with the control. These results showed that the addition of PB was an effective strategy to enhance the overall oxygen reduction performance and improve effluent quality of microbial fuel cells.