This study systematically investigated the photo-aging of polyvinyl chloride (PVC) in deionized water, estuary water, and seawater. As the concentration of Cl− increases, the carbonyl index (CI) of PVC during photo aging also increases, indicating that Cl− plays a dominant role in PVC photoaging in the environment, which enhance carbonyl index and •OH radical accumulation. Unlike previous studies, this study discovered that halogen radicals were also generated during PVC aging. Compared to •OH radicals, halogen radicals exhibit stronger selectivity and are more conducive to the photo aging of PVC. Additionally, it was found that PVC shows specific toxicity to Paramecia caudatum at various concentrations both before and after aging, affecting the reproduction process of Paramecia caudatum. This study elucidates the mechanism by which anions in natural water bodies affect the rate of PVC aging, providing a scientific basis for understanding the photodegradation of MPs in the ocean.

中文翻译：

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海洋环境中紫外线加速聚氯乙烯老化的机理：自由基的作用


本研究系统地研究了聚氯乙烯（PVC）在去离子水、河口水和海水中的光老化情况。随着Cl−浓度的增加，PVC在光老化过程中的羰基指数（CI）也增加，表明Cl−在环境中的PVC光老化中起主导作用，增强了羰基指数和·OH自由基的积累。与之前的研究不同，这项研究发现PVC老化过程中也会产生卤素自由基。与·OH自由基相比，卤素自由基表现出更强的选择性，更有利于PVC的光老化。此外，研究还发现，不同浓度的PVC在老化前后均对尾草履虫表现出特异性毒性，影响尾草履虫的繁殖过程。该研究阐明了天然水体中的阴离子影响PVC老化速率的机制，为了解海洋中MP的光降解提供了科学依据。