Photocatalytic debromination of polybrominated diphenyl ethers (PBDEs) on metal doped TiO2 nanocomposites: Mechanisms and pathways

Rui Wang; Ting Tang; Yanchun Wei; Dai Dang; Kaibo Huang; Xingwei Chen; Hua Yin; Xueqin Tao; Zhang Lin; Zhi Dang; Guining Lu

doi:10.1016/j.envint.2019.03.011

Photocatalytic debromination of polybrominated diphenyl ethers (PBDEs) on metal doped TiO₂ nanocomposites: Mechanisms and pathways

Environ Int. 2019 Jun:127:5-12. doi: 10.1016/j.envint.2019.03.011. Epub 2019 Mar 16.

Authors

Rui Wang¹, Ting Tang¹, Yanchun Wei², Dai Dang³, Kaibo Huang¹, Xingwei Chen⁴, Hua Yin⁵, Xueqin Tao², Zhang Lin⁶, Zhi Dang⁵, Guining Lu⁷

Affiliations

¹ School of Environment and Energy, South China University of Technology, Guangzhou 510006, China.
² School of Environmental Science and Engineering, Zhongkai University of Agriculture and Engineering, Guangzhou 510225, China.
³ School of Chemical Engineering and Light Industry, Guangdong University of Technology, Guangzhou, Guangdong 510006, China. Electronic address: dangdai@gdut.edu.cn.
⁴ School of Chemical Engineering and Light Industry, Guangdong University of Technology, Guangzhou, Guangdong 510006, China.
⁵ School of Environment and Energy, South China University of Technology, Guangzhou 510006, China; The Key Lab of Pollution Control and Ecosystem Restoration in Industry Clusters, Ministry of Education, Guangzhou 510006, China.
⁶ School of Environment and Energy, South China University of Technology, Guangzhou 510006, China; Guangdong Provincial Engineering and Technology Research Center for Environmental Nanomaterials, Guangzhou 510006, China.
⁷ School of Environment and Energy, South China University of Technology, Guangzhou 510006, China; The Key Lab of Pollution Control and Ecosystem Restoration in Industry Clusters, Ministry of Education, Guangzhou 510006, China. Electronic address: lutao@scut.edu.cn.

PMID: 30889398
DOI: 10.1016/j.envint.2019.03.011

Abstract

Nanoparticles of four noble metal doped titanium dioxide (i.e., Pd/TiO₂, Ag/TiO₂, Pt/TiO₂ and Cu/TiO₂) were synthesized and investigated for their effectiveness to degrade polybrominated diphenyl ethers (PBDEs) under UV light. All the investigated noble metal additives can greatly enhance the performance of TiO₂ to degrade 2,2',4',4'-tetrabromodiphenyl ether (BDE-47). However, the debromination pathways of BDE-47 in Ag/TiO₂ and Cu/TiO₂ systems are just contrary to those in Pd/TiO₂ and Pt/TiO₂ systems, and there was an induction period in the former systems but not in the latter systems. The hydrogenation experiment suggests a direct H-atom transfer mechanism in Pd/TiO₂ and Pt/TiO₂ systems, while in Ag/TiO₂ and Cu/TiO₂ systems, electron transfer is still the dominant mechanism. Electronic method was applied to explain why BDE-47 exhibit different debromination pathways based on different degradation mechanism. In addition, oxygen was proved to be able to capture both electrons and H atoms, and thus can greatly inhibit the degradation of PBDEs in all investigated systems. Finally, the merit and demerit of each metal doped TiO₂ were discussed in detail, including the reactivity, stability and the generation of byproducts. We proposed our study greatly enhance our understanding on the mechanisms of PBDE degradation in various metal doped TiO₂ systems.

Keywords: Debromination pathways; Mechanisms; Photocatalytic degradation; Polybrominated diphenyl ethers; Titanium dioxide.

Publication types

Research Support, Non-U.S. Gov't

MeSH terms

Catalysis
Halogenated Diphenyl Ethers / chemistry*
Nanocomposites / chemistry*
Photochemical Processes*
Titanium / chemistry*
Ultraviolet Rays

Substances

Halogenated Diphenyl Ethers
2,2',4,4'-tetrabromodiphenyl ether
titanium dioxide
Titanium