期刊
WATER RESEARCH
卷 173, 期 -, 页码 -出版社
PERGAMON-ELSEVIER SCIENCE LTD
DOI: 10.1016/j.watres.2020.115564
关键词
Polystyrene microplastic; Reactive oxygen species; Environmentally persistent free radicals; Phototransformation; Aquatic environments
资金
- National Natural Science Foundation of China [41571446, 21737003, 41877126]
- National Key R&D Program of China [2018YFC1802004, 2018YFC1801003]
- Shaanxi Key R&D Program of China [2019ZDLNY01-02-01]
- One Hundred Talents program of Shaanxi Province [SXBR9171]
- CAS Youth Innovation Promotion Association [2016380]
- Shaanxi Science Fund for Distinguished Young Scholars [2019JC-18]
Microplastics may experience photoaging and breakdown into nanoplastics in aquatic environment as a result of long-term light irradiation. However, the underlying mechanisms responsible for the photodegradation of microplastics are largely overlooked. In this study, the photodegradation of microplastics, utilizing polystyrene microplastic (PS-MP) as a model, was investigated under irradiation with simulated solar light for as long as 150 d. A large amount of reactive oxygen species (ROS), including O-2(center dot), O-1(2), H2O2 and center dot OH, were detected in the PS-MP suspension due to light irradiation, which displayed significant relationships with the generated environmentally persistent free radicals (EPFRs). Distinct photoaging of PS-MP was observed with increased surface roughness and decreased particle size. However, these photoaging effects were significantly inhibited by ROS quenchers, suggesting that the generation ROS played a vital role in the PS-MP phototransformation. In addition, ROS induced formation of more oxidative functional groups on the PS-MP, thus enhancing the negative surface potential and the stability of PS-MP in water. This study elucidated the mechanism of formation of ROS by simulated solar light irradiated MPs and their subsequent roles in the phototransformation of MP, thus expanding current knowledge on the fate of MPs in aquatic environments. (c) 2020 Elsevier Ltd. All rights reserved.
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