Comprehensive exploration of the ultraviolet degradation of polychlorinated biphenyls in different media

Chenchen Huang; Yanhong Zeng; Xiaojun Luo; Zihe Ren; Yankuan Tian; Bixian Mai

doi:10.1016/j.scitotenv.2020.142590

Comprehensive exploration of the ultraviolet degradation of polychlorinated biphenyls in different media

Sci Total Environ. 2021 Feb 10;755(Pt 2):142590. doi: 10.1016/j.scitotenv.2020.142590. Epub 2020 Oct 5.

Authors

Chenchen Huang¹, Yanhong Zeng², Xiaojun Luo³, Zihe Ren¹, Yankuan Tian³, Bixian Mai³

Affiliations

¹ State Key Laboratory of Organic Geochemistry and Guangdong Key Laboratory of Environmental Protection and Resources Utilization, Guangzhou Institute of Geochemistry, Chinese Academy of Sciences, Guangzhou 510640, China; University of Chinese Academy of Sciences, Beijing 100049, China.
² State Key Laboratory of Organic Geochemistry and Guangdong Key Laboratory of Environmental Protection and Resources Utilization, Guangzhou Institute of Geochemistry, Chinese Academy of Sciences, Guangzhou 510640, China; Guangdong-Hong Kong-Macao Joint Laboratory for Environmental Pollution and Control, Guangzhou Institute of Geochemistry, Chinese Academy of Sciences, Guangzhou 510640, China. Electronic address: zengyh@gig.ac.cn.
³ State Key Laboratory of Organic Geochemistry and Guangdong Key Laboratory of Environmental Protection and Resources Utilization, Guangzhou Institute of Geochemistry, Chinese Academy of Sciences, Guangzhou 510640, China; Guangdong-Hong Kong-Macao Joint Laboratory for Environmental Pollution and Control, Guangzhou Institute of Geochemistry, Chinese Academy of Sciences, Guangzhou 510640, China.

PMID: 33059143
DOI: 10.1016/j.scitotenv.2020.142590

Abstract

As one of the most important natural transformation processes, photodegradation deserves more attention and research. In the current work, we comprehensively explored the photochemical behaviors of polychlorinated biphenyls (PCBs) in n-hexane (Hex), methanol/water, and silica gel under UV-irradiation. Photodegradation rates were found to be faster in methanol/water than in Hex. All of the three photochemical systems generated sigmatropic rearrangement products. The dominant photodegradation pathways were dechlorination, dechlorination/methoxylation/hydroxylation, and hydroxylation in Hex, methanol/water, and silica gel systems, respectively. Furthermore, some new photodegradation products, such as polychlorinated biphenyl ethers, polychlorinated dibenzofurans, polychlorinated biphenylenes, and methylated polychlorinated biphenyls, are reported for the first time. These findings would provide deeper insight into the phototransformation behaviors of PCBs.

Keywords: Methanol/water; N-hexane; Polychlorinated biphenyls; Silica gel; UV-photodegradation.