Based on the deficiency of the Fe 2+ catalyzed persulfate (PDS) process, ultraviolet (UV) synergistic Fe 2+ activated PDS system was introduced in this study for the degradation of acid orange 7 (AO7) dye. The effects of different initial pH, PDS dosage, Fe 2+ dosage, and different UV intensities on the degradation rate of AO7 were investigated, and a kinetic model for the apparent reaction rate was determined. The results showed that the UV/Fe 2+ /PDS system was effective in degrading AO7 in a wide pH range. Under optimal conditions, 96 % removal of AO7 was achieved in 10 min. The effects of different inorganic anions on AO7 were discussed; Cl − had little effect on the degradation effect, and SO 4 2− , NO 3 − and HCO 3 − inhibited the degradation of AO7 by the system to varying degrees. The presence of reactive radicals (SO 4 ·− and·OH) in the reaction was determined by quenching experiments and EPR capture and their degradation contribution was further investigated. Nine intermediates of AO7 were detected by LC-MS/MS, and the degradation pathway of AO7 was inferred by combining with UV-Vis spectra. Finally, the ecotoxicity and tritogenic effects of AO7 intermediates were assessed by Toxtree and T.E.S.T toxicity prediction models, which showed that the final degradation product toxicity was non-mutagenic, non-teratogenic, and devoid of hereditary and non-hereditary carcinogenicity.
The degradation of indomethacin (IM) by ferrous ion-activated potassium peroxydisulfate (Fe2+/PDS) was investigated. We aimed to determine the optimal conditions for the removal of IM under different concentrations of Fe2+and PDS, evaluate the effects of operational parameters (solution pH, humic acid (HA), N2 bubbling and persulfate species), and propose the degradation mechanism of IM by the Fe2+/PDS system. The sequential addition of Fe2+ led to an improvement in the IM degradation and TOC removal efficiency. When the molar ratio of IM/PDS/Fe2+ was 1 : 1.5 : 2, the IM was almost completely degraded. Restrictions to the degradation efficiency of IM were caused by increasing the solution pH, bubbling with nitrogen, or through the addition of HA. A low concentration of Cl− had no effect on the reaction, while a high concentration led to a dramatic inhibitory effect. In addition, quenching experiments revealed that SO4˙− was the major active radical for the degradation of IM by ferrous ion-activated peroxydisulfate. Based on the identification of transformation products by liquid chromatography-mass spectrometry (LC-MS/MS), the pathways of the ferrous–peroxydisulfate oxidative system for the degradation of IM were tentatively proposed.
危险品化学品经营许可证（带存储）