Efficient Photodegradation of Pfoa over Sphere Biobr Modified Nano-Tio2: Hole-Remained Oxidation Mechanism and Potential Application

Photo-induced holes (h + ) oxidation is believed to be an effective technology for PFOA removal. How to remain more h + on the surface of photocatalysts participating in the PFOA photodegradation was the key issue. Herein, a highly efficient sphere BiOBr-modified nano-TiO 2 (P25) was synthesized and used for PFOA photodegradation through direct oxidation with h + . A high number of h + could be generated and remained the surface of P25/BiOBr due to the appropriate position of the CB and VB levels between P25 and BiOBr. Meanwhile, PFOA molecules was coordinated to the P25/BiOBr’s surface via unidentate binding, it can be directly activated and oxidized by the holes, resulting in 99.5% degradation efficiency under simulated solar light irradiation for 100 min. Reactive oxygen species (ROS) generation, scavenging and trapping analysis indicated PFOA degradation followed the h + directly oxidation way. The C4−C7 shorter-chain perfluoroalkyl carboxylic acids (PFCAs) were major intermediates, suggesting the photodegradation process reacted in a stepwise mode. For a real aqueous environment of Tangxun lake, stable common anions and NOM would restrain the PFOA photodegradation. However, adding 10 mg/L NO 3 - or HA could resist the inhibition effect of PFOA photodegradation. These findings gave an alternative strategy to drive h + directly oxidation way for the treatment of PFOA contaminated water.