Unified photoelectrocatalytic microbial fuel cell harnessing 3D binder-free photocathode for simultaneous power generation and dual pollutant removal

Abstract A combined photoelectrocatalytic microbial fuel cell (photo-MFC) with BiOCl/reduced graphene oxide aerogel (BGA) photocathode is constructed for simultaneous power generation and dual pollutant removal. Owing to the lower cathodic internal resistance and enhanced reaction rate under light irradiation, the BGA photo-MFC exhibits excellent power generation capacity (696.51 ± 5.27 mV and 7.33 ± 0.23 W m−3) in comparison with the single MFC process (455.36 ± 7.18 mV and 1.88 ± 0.09 W m−3). Meanwhile, the removal efficiency of oxytetracycline (OTC) in the anode rises to 98.93 ± 0.15% after four days of operation, and the biotoxicity of OTC effluent to Escherichia coli DH5α is largely eliminated. At the cathode, 97.28 ± 0.64% of 40 mg L−1 methyl orange (MO) can be degraded with the highest kinetic constant of 0.304 h−1 at the optimal pH of 3. High-throughput sequencing analysis reveals that the Geobacter are enriched and responsible for the enhanced power generation of the BGA photo-MFC. The synergistic effects of photocatalysis and MFC in BGA photo-MFC dramatically increase the removal of OTC and MO in their respective chambers while producing energy in situ to drive the process without additional energy consumption, and exhibit extensive application prospects for actual wastewater treatment.