title: Photocatalytic degradation of terephthalic acid on sulfated titania particles and identification of fluorescent intermediates.
abstract: Terephthalic acid (TA) is toxic and known as an endocrine disruptor. In this paper, the photocatalytic degradation of TA using sulfated titanium dioxide SO4(2-)/TiO2 photocatalysts was investigated. The photocatalysts were prepared by sol-gel method and characterized by XRD, SEM, BET, ICP/MS and spectroscopic methods. Their activities were compared with bare TiO2 and Degussa P25. The effects of catalyst sulfur content, the initial TA concentration and pre-treatment conditions (O2, N2 or non-pretreated) were studied. O2 functions were also explored. Since there had been no comprehensive study of fluorescent intermediates reported yet, we investigated the intermediates and discovered 5 new intermediates (4 fluorescent and 1 non-fluorescent) which were identified by gas chromatography-mass spectrometry (GC/MS) and fluorescence spectroscopy. These intermediates are complementary to the previously identified carboxylic acid intermediates and might provide new insights to the mechanism of photocatalytic degradation of TA. Since TA is widely used as a probing molecule for photocatalytically generated (·)OH radicals, the ratios of fluorescent intermediates of TA degradation may provide new clues to the photocatalytic activity and mechanism. Based on the results obtained, the possible destruction pathway of TA is also proposed.
authors.affiliation: Department of Chemistry, National University of Singapore, 3 Science Drive 3, Singapore 117543, Singapore.
authors.forename: Xuan Hao
authors.initials: XH
authors.lastname: Lin
authors.affiliation: Department of Chemistry, National University of Singapore, 3 Science Drive 3, Singapore 117543, Singapore.
authors.forename: Si Ni
authors.initials: SN
authors.lastname: Lee
authors.affiliation: Department of Chemistry, National University of Singapore, 3 Science Drive 3, Singapore 117543, Singapore.
authors.forename: Wenlin
authors.initials: W
authors.lastname: Zhang
authors.affiliation: Department of Chemistry, National University of Singapore, 3 Science Drive 3, Singapore 117543, Singapore; NUS Environmental Research Institute (NERI), #02-01, T-Lab Building (TL), 5A Engineering Drive 1, Singapore 117411, Singapore. Electronic address: chmlifys@nus.edu.sg.
authors.forename: Sam Fong Yau
authors.initials: SF
authors.lastname: Li
keywords: Intermediate; OH radical; Photocatalyst; Sulfated TiO(2); Terephthalic acid