Reaction pathways of dimethyl phthalate degradation in TiO2-UV-O2 and TiO2-UV-Fe(VI) systems.
Reaction pathways of dimethyl phthalate degradation in TiO2-UV-O2 and TiO2-UV-Fe(VI) systems.
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DOI：
10.1016/j.chemosphere.2008.01.055
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发表时间：
2008-05
期刊：
影响因子：
8.8
通讯作者：
Baoling Yuan;Xiang-zhong Li;N. Graham
中科院分区：
文献类型：
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作者：
Baoling Yuan;Xiang-zhong Li;N. Graham
以氧气（O2）和高铁酸盐（Fe（VI））为电子受体，研究了TiO 2悬浮液在紫外光照射下光催化降解邻苯二甲酸二甲酯（DMP）.实验表明，Fe（VI）是比O2更有效的电子受体，能清除催化剂表面的导带电子。通过HPLC和GC/MS分析鉴定了一些主要的中间产物。分析结果表明，在TiO 2-UV-O2体系中，邻苯二甲酸二甲酯和邻苯二甲酸二甲酯是光催化降解的两个主要中间产物，而在TiO 2-UV-Fe（VI）体系中，邻苯二甲酸是光催化降解的主要中间产物。这些结果表明，TiO 2-UV-O2和TiO 2-UV-Fe（VI）体系中的光催化降解遵循不同的反应途径。电子自旋共振分析证实了TiO 2-UV-O2反应体系中存在羟基自由基，并怀疑TiO 2-UV-Fe（VI）反应体系中存在未知的自由基物种（最有可能是铁氧物种）。提出了TiO_2-UV-O_2和TiO_2-UV-Fe（VI）反应体系中光催化降解的两种途径方案。据信，在TiO 2-UV-O 2反应体系中形成的自由基优选地攻击α-Al 2 O3的芳环，而相反，在TiO 2-UV-Fe（VI）反应体系中形成的自由基攻击α-Al 2 O3的烷基链。
The photocatalytic degradation of dimethyl phthalate (DMP) in aqueous TiO2suspension under UV illumination has been investigated using oxygen (O2) and ferrate (Fe(VI)) as electron acceptors. The experiments demonstrated that Fe(VI) was a more effective electron acceptor than O2for scavenging the conduction band electrons from the surface of the catalyst. Some major intermediate products from DMP degradation were identified by HPLC and GC/MS analyses. The analytical results identified dimethyl 3-hydroxyphthalate and dimethyl 2-hydroxyphthalate as the two main intermediate products from the DMP degradation in the TiO2–UV–O2system, while in contrast phthalic acid was found to be the main intermediate product in the TiO2–UV–Fe(VI) system. These findings indicate that DMP degradation in the TiO2–UV–O2and TiO2–UV–Fe(VI) systems followed different reaction pathways. An electron spin resonance analysis confirmed that hydroxyl radicals existed in the TiO2–UV–O2reaction system and an unknown radical species (most likely an iron–oxo species) is suspected to exist in the TiO2–UV–Fe(VI) reaction system. Two pathway schemes of DMP degradation in the TiO2–UV–O2and TiO2–UV–Fe(VI) reaction systems are proposed. It is believed that the radicals formed in the TiO2–UV–O2reaction system preferably attack the aromatic ring of the DMP, while in contrast the radicals formed in the TiO2–UV–Fe(VI) reaction systems attack the alkyl chain of DMP.