Capture of phosphates in surface water by TiO2 nanoparticles under UV irradiation

Abstract The capture of orthophosphates and total phosphorus from the Pudong Canal river in the Pudong District of Shanghai by TiO 2 nanoparticles is studied using a rotating photoreactor and the nano-TiO 2 photocatalyst Degussa P25. The effects of UV irradiation intensity in a range of 20–74 mW/cm 2 , the loading of the TiO 2 nanoparticles in a range of 0.05–0.1 g/L, irradiation time up to 4 h, and pH values in a range of 2–10.5 on the capture efficiency are investigated. The results show that the capture of orthophosphates and total P are significantly enhanced by UV irradiation; at a loading of 0.1 g/L and an irradiation intensity above 36 mW/cm 2 , orthophosphates and total phosphorus are rapidly captured by TiO 2 nanoparticles, causing an observed reduction from 0.4 mg/L down to 0.02 mg/L. pH values in a range of 2–10.5 have little effect on the capture efficiency of orthophosphates and total phosphorus.