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ROS-mediated photoaging pathways of nano- and micro-plastic particles under UV irradiation

Water Research 2022 226 citations ? Citation count from OpenAlex, updated daily. May differ slightly from the publisher's own count. Score: 55 ? 0–100 AI score estimating relevance to the microplastics field. Papers below 30 are filtered from public browse.

Jiajun Duan, Jiajun Duan, Jiajun Duan, Runzi Cao, Runzi Cao, Wen Zhang, Runzi Cao, Yang Li Yang Li Jiajun Duan, Yang Li Yang Li Runzi Cao, Yang Li Enxiang Shang, Enxiang Shang, Yang Li Runzi Cao, Yang Li Yang Li Yang Li Yang Li Jiajun Duan, Jiajun Duan, Enxiang Shang, Jianan Gao, Yang Li Yang Li Yang Li Yang Li Enxiang Shang, Jiajun Duan, Runzi Cao, Runzi Cao, Runzi Cao, Yang Li Yang Li Runzi Cao, Yang Li Yang Li Enxiang Shang, Enxiang Shang, Yang Li Yang Li Enxiang Shang, Enxiang Shang, Wen Zhang, Enxiang Shang, Enxiang Shang, Enxiang Shang, Yang Li Enxiang Shang, Yang Li Jiajun Duan, Jiajun Duan, Yang Li Jiajun Duan, Wen Zhang, Wen Zhang, Yang Li Jiajun Duan, Wen Zhang, Yang Li Wen Zhang, Yang Li Yang Li Wen Zhang, Yang Li Yang Li Yang Li Wen Zhang, Yang Li Yang Li Wen Zhang, Yang Li

Summary

Researchers investigated the role of reactive oxygen species in the photoaging of nano- and micro-plastic particles under UV irradiation. The study found that bare polystyrene nanoparticles generated hydroxyl radicals and singlet oxygen, while surface coatings and larger particle sizes reduced ROS generation. The findings help explain the mechanisms by which UV exposure breaks down plastic particles in aquatic environments.

Polymers

PC PE PET PP PS PVC

Reactive oxygen species (ROS) generation is considered as an important photoaging mechanism of microplastics (MPs) and nanoplastics (NPs). To elucidate the ROS-induced MP/NP aging processes in water under UV irradiation, we examined the effects of surface coatings, polymer types and grain sizes on ROS generation and photoaging intermediates. Bare polystyrene (PS) NPs generated hydroxyl radicals (•OH) and singlet oxygen (O), while coated PS NPs (carboxyl-modified PS (PS-COOH), amino-modified PS (PS-NH)) and PS MPs generated fewer ROS due to coating scavenging or size effects. Polypropylene, polyethylene, polyvinyl chloride, polyethylene terephthalate and polycarbonate MPs only generated •OH. For aromatic polymers, •OH addition preferentially occurred at benzene rings to form monohydroxy polymers. Excess •OH resulted in H abstraction, CC scission and phenyl ring opening to generate aliphatic ketones, esters, aldehydes, and aromatic ketones. For coated PS NPs, •OH preferentially attacked the surface coatings to result in decarboxylation and deamination reactions. For aliphatic polymers, •OH attack resulted in the formation of carbonyl groups from peracid, aldehyde or ketone via H abstraction and CC scission. Moreover, O might participate in phenyl ring opening for PS NPs and coating degradation for coated PS NPs. This study facilitates understanding the ROS-induced weathering process of NPs/MPs in water under UV irradiation.

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