五氧化二钒类Fenton降解邻苯二甲酸二乙酯的机制研究

发展了基于五氧化二钒(V_2O_5)和过氧化氢(H_2O_2)的新型类Fenton体系,探索了此体系产生羟基(·OH)的机制及降解邻苯二甲酸二乙酯(DEP)的效率;并考察了V_2O_5投加量、H_2O_2浓度,以及草酸对DEP降解的影响。结果表明,当V_2O_5投加量为0.1 g·L-1,H_2O_2浓度为2.0 mmol·L-1,反应24 h后,对DEP(25 mg·L-1)的降解率可达61.1%,增加或降低V_2O_5投加量和H_2O_2浓度均不利于DEP的降解。利用电子顺磁共振技术(Electron Paramagnetic Resonance,EPR)耦合5,5-二甲基-1-吡咯啉氮氧化物(DMPO)为捕获剂对反应体系中的主导自由基进行鉴定,发现·OH是体系降解DEP的主要活性物种,利用苯甲酸作为探针分子实现了·OH的间接定量,并初步推测了V_2O_5活化H_2O_2的过程。

Vanadium Pentoxide-Based Fenton-like Reactions for Diethyl Phthalate Degradation

In this study, a novel Fenton-like reaction based on V₂O₅ and H₂O₂ was developed, and the mechanism of hydroxyl radical production as well as the efficiency for diethyl phthalate (DEP) degradation was explored in these processes. Additionally, the effects of V₂O₅ loading, H₂O₂ concentration and oxalic acid on DEP degradation in the V₂O₅/H₂O₂ system were also examined. The results showed that 61.1% of 25 mg L^-1 DEP was degraded with 2 mmol L^-1 H₂O₂ in the presence of 0.1 g L^-1 V₂O₅ within 24 h, which indicated that V₂O₅ exhibits an excellent ability to catalyze the decomposition of H₂O₂ for DEP degradation, while both increasing and decreasing V₂O₅ loading or H₂O₂ concentration inhibited DEP degradation. Electron paramagnetic resonance (EPR) technique coupled with DMPO as spin-trapping agent was used to identify the dominant reactive species, which indicated that hydroxyl radical was the main free radical for DEP degradation in the V₂O₅/H₂O₂ system. Chemical probe method with benzoic acid (BA) was further used to quantify the formation of hydroxyl radical and elucidated mechanism of this process.