H 2 O 2 regulates the production of reactive oxygen species in TiO 2 system and the degradation process of pentachlorophenol

The titanium dioxide photocatalytic oxidation technology of pentachlorophenol (PCP) has attracted widespread attention because of its high degradation efficiency and low toxicity. How to reasonably regulate the production of highly toxic intermediates during the degradation of PCP is currently the hotspot. The photocatalytic degradation of PCP is closely related to the production of reactive oxygen species (ROS). This article studied the effect of H 2 O 2 addition on the production of ROS including •OH, O 2 •− and H 2 O 2 in three different types of TiO 2 photocatalytic systems and their effects on the degradation efficiency of PCP. The results showed that after H 2 O 2 was added, the amount of three kinds of ROS produced by the P25 solution increased, and the degradation rate k of PCP increased. The anatase TiO 2 solution produced less •OH, but more O 2 •− and H 2 O 2 after H 2 O 2 was added. The amount of three kinds of ROS produced by the rutile TiO 2 solution increased, and the degradation rate of PCP increased by 50 times. The effects of three kinds of TiO 2 /H 2 O 2 systems on the photocatalytic degradation of PCP and its intermediate acute toxicity were identified by high performance liquid chromatography and luminescence inhibition. The results showed that there were no highly toxic intermediate products such as tetrachloro-1,4-benzoquinone during the degradation process, and the acute toxicity during degradation was significantly reduced. These results indicated that the addition of H 2 O 2 can regulate the ROS production and PCP degradation process in TiO 2 photocatalytic system, and significantly reduced the acute toxicity during the degradation of PCP.