The promotion of Ag₃PO₄ photocatalysis on methylene blue removal and electricity generation in microbial fuel cell

The photocatalysis promoted microbial fuel cell (photo-MFC) system is designed to improve the degradation efficiency of recalcitrant organic pollutants in wastewater. In order to avoid the damage of UV light and reactive oxygen species to microorganisms, narrow bandgap Ag₃PO₄ photocatalyst is chosen and separated with TiN bioanode in anode chamber of MFC. Under visible light irradiation, the synergistic effect between photodegradation and biodegradation yielded a decolorization efficiency of 95.8% MB and a maximum power density of 2.90 W m⁻² for 10 mg L⁻¹ MB co-substrate with sodium acetate. The chemical oxygen demand (COD) and total organic carbon (TOC) removal efficiencies of co-substrate in the photo-MFC system are 83.21% and 72.47%, much higher than that of photocatalysis alone (8.67% for COD and 9.65% for TOC). All of the degradation efficiency, power density and mineralization capacity of the photo-MFC system are higher than that of single MFC or photocatalysis. Microbial community analysis shows that Pseudomonas (73.75%) and Geobacter (19.62%) are the main genera of the bioanode in the photo-MFC system. The abundance of Pseudomonas is increased by photocatalysis. This photo-MFC coupled system has great potential application in wastewater treatment and energy recovery.