Activation of Peracetic Acid by Trace Ferrous Ion and Vacuum Ultraviolet for the Ultrafast Degradation of PPCPs

Herein, the vacuum ultraviolet system (VUV) was introduced into the peracetic acid/ferrous ion (PAA/Fe(II)) process for the first time to treat the micropollutants in water. When contaminant concentrations (i.e., 10 μM) are comparable to those reported in previous literature, the VUV/PAA/Fe(II) system with a low dosage of PAA (i.e., 50 μM) and trace Fe(II) ion (i.e., 5 μM to 10 μM) exhibited remarkable performance for carbamazepine (CBZ) degradation (more than 90%) within just 5 min and at a wide pH range from 3.0 to 9.0. The outstanding performance of the VUV/PAA/Fe(II) system was attributed to the favorable synergistic effect of the UV-induced Fe(II) regeneration cycle and the activation of PAA as well as H₂O₂(coming from both the PAA solution and reactions occurring in the VUV system). Furthermore, the calculated low EE/O value confirmed the energy saving characteristic of the VUV/PAA/Fe(II) system. Considering that the initial Fe(II) concentration required by the system is within the Fe(II) concentration range in natural groundwater and can be further reduced to the value lower than the commonly utilized threshold of Fe for drinking water, this study provides a possibility for the improvement of the UV-based Fenton-like system by in situ utilization of inherent trace metal ions in natural water.