Peroxymonosulfate enhanced visible light photocatalytic degradation bisphenol A by single-atom dispersed Ag mesoporous g-C3N4 hybrid

Single-atom dispersed Ag modified mesoporous graphitic carbon nitride (Ag/mpg-C3N4) hybrid was synthesized by co-condensation method and employed as a visible light photocatalyst. In the presence of peroxymonosulfate (PMS), Ag/mpg-C3N4 showed excellent performance for the degradation of bisphenol A (BPA). 100% BPA and 80% TOC could be removed with 0.1 g/L catalyst and 1 mM PMS under visible light (λ > 400 nm) within 60 min. The reason for the enhanced performance is possibly due to the synergistic effect of single-atom Ag and mpg-C3N4. On the one hand, more visible light could be captured with the introduction of Ag; on the other hand, the existence of PMS promotes the separation efficiency of photogenerated electron-hole pairs. Electron spin resonance (ESR) and free radicals quenching experiment suggest that the major reactive oxygen species (ROS) are sulfate radical (SO4−), superoxide radicals (O2−) and photogenerated holes, while the role of hydroxyl radicals (OH) is insignificant in this process. The findings of this work highlighted the great potential of g-C3N4 as photocatalysts and elucidated a new opportunity for PMS remediation of contaminated water.