Photocatalytic removal of phenanthrene and algae by a novel Ca-AgPO composite under visible light: Reactivity and coexisting effect.

In this study, the feasibility of a novel Ca-AgPO composite with visible light irradiation for the phenanthrene (PHE) degradation and algae inactivation in artificial seawater was firstly investigated. The experimental findings revealed that AgPO phase was sucessfully formed on the Ca-based material, and the presence of Ca-based material could effectively keep AgPO particles stable. An excellent performance on PHE degradation or algae inactivation was observed from Ca-AgPO composite under visible light irradiation. The degradation of PHE or inactivation of algae not only could be efficiently achieved in the single mode, but also could be successfully achieved in the coexisting mode. Above 96% of PHE and algae were simultaneously removed within 12 h in the Ca-AgPO/visible light system. It was further observed that the degradation of PHE and/or inactivation of algae increased with the increase of Ca-AgPO dosage. HO was the primary radical responsible for PHE degradation, whereas HO and Ag released from Ca-AgPO mainly contributed to the algae inactivation. A possible mechanism involving the catalytic removal of PHE and algae by Ca-AgPO under visible light irradiation was proposed. This study provides helpful guide for the simultaneous removal of various pollutants in real seawater.