Enhanced degradation of E2/EE2 by BiPO4/AgI/BC composite photocatalysts via BC-enhanced ·O2-

This study presents the synthesis of highly active BiPO4/AgI/BC composite photocatalysts via a green, simple, and low-cost ambient temperature precipitation method. The electron transfer rate and visible-light responsiveness can be effectively enhanced by utilizing BiPO4 compounded with the semiconductor AgI, which has a narrow bandgap and good visible-light responsiveness. Additionally, the introduction of biocarbon (BC) enhances the absorption and separation of photogenerated electrons and holes under visible light. Notably, the synthesized BP-AgI0.6-BC5% could remove 99.16% and 99.7% of EE2 and E2, respectively, at a concentration of 3 mg/L after 40 min of light exposure. The capture experiments and electron paramagnetic resonance spectroscopy reveal that the main active substance in the system is ·O2-, with BC playing a crucial role in enhancing the ·O2- concentration in the system. The findings from phytotoxicity and antimicrobial tests reveal that BP-AgI0.6-BC5% can efficiently degrade pollutants, producing degradation products that are substantially less toxic than the original pollutants. Moreover, it can remove more than 99.99% of E. coli under both dark and light conditions, demonstrating excellent antimicrobial performance. Additionally, the photocatalytic mechanism and degradation pathway were examined in this study. Notably, the composite photocatalysts synthesized in this study achieved efficient degradation of EE2 and E2 under visible light conditions while exhibiting efficient bactericidal function. Furthermore, the room-temperature preparation method is conducive to industrial-scale production, highlighting a better prospect for practical applications.