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Mechanistic Studies of TiO 2 Photocatalysis and Fenton Degradation of Hydrophobic Aromatic Pollutants in Water
Author(s) -
Gong Yuanzheng,
Yang Chun,
Ji Hongwei,
Chen Chuncheng,
Ma Wanhong,
Zhao Jincai
Publication year - 2016
Publication title -
chemistry – an asian journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.18
H-Index - 106
eISSN - 1861-471X
pISSN - 1861-4728
DOI - 10.1002/asia.201601299
Subject(s) - pollutant , degradation (telecommunications) , photocatalysis , environmental chemistry , chemistry , aromaticity , environmental science , photochemistry , chemical engineering , organic chemistry , molecule , catalysis , computer science , engineering , telecommunications
HO–adduct radicals have been investigated and confirmed as the common initial intermediates in TiO 2 photocatalysis and Fenton degradations of water‐insoluble aromatics. However, the evolution of HO–adduct radicals to phenols has not been completely clarified. When 4‐d‐toluene and p‐ xylene were degraded by TiO 2 photocatalysis and Fenton reactions, respectively, a portion of the 4‐deuterium or 4‐CH 3 group (18–100 %) at the attacked ipso position shifted to the adjacent position of the ring in the formed phenols (NIH shift; NIH is short for the National Institutes of Health, to honor the place where this phenomenon was first discovered). The results, combined with the observation of a key dienyl cationic intermediate by in situ attenuated total reflectance FTIR spectroscopy, indicate that, for the evolution of HO–adduct radicals, a mixed mechanism of both the carbocation intermediate pathway and O 2 ‐capturing pathway occurs in both aqueous TiO 2 photocatalysis and aqueous Fenton reactions.