title: Efficient oxidative debromination of decabromodiphenyl ether by TiO2-mediated photocatalysis in aqueous environment.
abstract: Direct evidence was first demonstrated for the oxidative degradation of decabromodiphenyl ether (BDE209) in aqueous TiO(2) dispersions under UV irradiation (λ > 340 nm). BDE209 was hardly debrominated over TiO(2) in UV-irradiated acetonitrile dispersions, but the addition of water into the dispersions greatly enhanced its photocatalytic oxidative debromination. The debromination efficiency of BDE209 as high as 95.6% was achieved in aqueous TiO(2) dispersions after 12 h of UV irradiation. The photocatalytic oxidation of BDE209 resulted in generation of aromatic ring-opening intermediates such as brominated dienoic acids, which were further degraded by prolonging UV irradiation time. The photocatalytic oxidative debromination of BDE209 was further confirmed by the observation that the BDE209 degradation in water-acetonitrile mixtures with different water contents was positively correlated with the formation of •OH radicals, but not photogenerated electrons. The use of water not only avoided the scavenging of reactive radicals by organic solvent but also enhanced the adsorption of BDE209 on the surface of TiO(2), both of which favor the contact of BDE209 with photogenerated holes and •OH species. The confirmation of efficient oxidative degradation and debromination of BDE209 is very important for finding new ways to remove polybrominated diphenyl ethers from the environment.
authors.affiliation: College of Chemistry and Chemical Engineering, Huazhong University of Science and Technology, Wuhan 430074, PR China.
authors.forename: Aizhen
authors.initials: A
authors.lastname: Huang
authors.forename: Nan
authors.initials: N
authors.lastname: Wang
authors.forename: Ming
authors.initials: M
authors.lastname: Lei
authors.forename: Lihua
authors.initials: L
authors.lastname: Zhu
authors.forename: Yingying
authors.initials: Y
authors.lastname: Zhang
authors.forename: Zhifen
authors.initials: Z
authors.lastname: Lin
authors.forename: Daqiang
authors.initials: D
authors.lastname: Yin
authors.forename: Heqing
authors.initials: H
authors.lastname: Tang
mesh_terms: D001966:Bromine / Q000737:chemistry; D002384:Catalysis; D005411:Flame Retardants / Q000528:radiation effects; D055768:Halogenated Diphenyl Ethers / Q000737:chemistry* / Q000528:radiation effects; D010084:Oxidation-Reduction; D010777:Photochemistry; D014025:Titanium / Q000737:chemistry* / Q000528:radiation effects; D014466:Ultraviolet Rays; D014874:Water Pollutants, Chemical / Q000737:chemistry* / Q000528:radiation effects; D018508:Water Purification / Q000379:methods
chemical_list: D005411:Flame Retardants; D055768:Halogenated Diphenyl Ethers; D014874:Water Pollutants, Chemical; C009495:titanium dioxide; D014025:Titanium; C010902:decabromobiphenyl ether; D001966:Bromine