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.

Effects of titanium dioxide nanoparticles on lead bioconcentration and toxicity on thyroid endocrine system and neuronal development in zebrafish larvae

“…This increase was mainly caused by the large surface area of the NPs. The absorption behaviors of nano-TiO 2 include physical and chemical absorption Huang et al, 2013). The absorption experiment further indicated that nano-TiO 2 has a strong absorption capability for the higher surface of nano-TiO 2 .…”

Bioconcentration and metabolism of BDE-209 in the presence of titanium dioxide nanoparticles and impact on the thyroid endocrine system and neuronal development in zebrafish larvae

“…Accordingly, we also measured the bioconcentration of nano-TiO 2 (as Ti) in the larvae. The increased bioconcentration of BDE-209 in the presence of nano-TiO 2 could be attributed to the adsorption of organic contaminants due to the large surface area of the NPs; the sorption behaviors of nano-TiO 2 include physical sorption through electrostatic forces and chemical sorption (Huang et al, 2013;Tan et al, 2012). The adsorption experiment further indicated that nano-TiO 2 has a stronger adsorption capability for BDE-209.…”

Degradation of organophosphorus flame retardant tris (1-chloro-2-propyl) phosphate (TCPP) by visible light N,S-codoped TiO2 photocatalysts

“…However, applications for another important emerging pollutant's category like flame retardants have been investigated in a lesser extent. The existing studies are focused mainly on tetrabromobisphenol A and other polybrominated diphenyl ethers (PBDEs) [29][30][31][32][33] whereas for organophosphorus flame retardants (OPFRs), which have replaced the banned PBDEs, the data are very scarce [34]. OPFRs are extensively used in various different applications [35,36] and they can migrate from the host materials into surrounding environmental media relatively easily by volatilization, leaching and/or abrasion due to the non-chemically bonded incorporation for many of them in the material matrices [36].…”