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Title: Reaction pathways of dimethyl phthalate degradation in TiO₂-UV-O₂and TiO₂-UV-Fe(VI) systems
Authors: Yuan, Bao-Ling
Li, Xiang-zhong
Graham, Nigel
Subjects: Dimethyl phthalate
Electron acceptor
Issue Date: May-2008
Publisher: Elsevier
Source: Chemosphere, May 2008, v. 72, no. 2, p.197-204.
Abstract: 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.
Rights: Chemosphere © 2008 Elsevier. The journal web site is located at
Type: Journal/Magazine Article
DOI: 10.1016/j.chemosphere.2008.01.055
ISSN: 0045-6535
Appears in Collections:CEE Journal/Magazine Articles

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