Photo-aging of polyvinyl chloride microplastic in the presence of natural organic acids

Chao Wang, Zeyu Xian, Xin Jin, Sijia Liang, Zhanghao Chen, Bo Pan, Bing Wu, Yong Sik Ok, Cheng Gu

Research output: Contribution to journalArticle

Abstract

In this study, a new photo-aging pathway in the aquatic environments and the underlying transformation mechanism were described for polyvinyl chloride microplastic (PVC-MP). Our results indicated that the photo-aging of PVC-MP was strongly dependent on particle size and the aging reaction could be facilitated in the presence of low-molecular-weight organic acid (LMWOA) and LMWOA-Fe(III) complex under simulated and natural sunlight irradiation and ambient conditions. The hydroxyl radical (OH•) generated from the photolysis of LMWOA or its ferric complexes played a dominant role in enhancing PVC-MP degradation. In situ Fourier transform infrared and Raman spectroscopic techniques and theoretical calculations further confirmed that C–Cl bond cleavage and formation of polyene and carbonyl underwent on the PVC-MP surface, especially in the presence of LMWOA and LMWOA-Fe(III). Moreover, PVC-MP surface oxidation also led to the increase of the specific surface area and affinity towards water as indicated by the results of scanning electron microscopy, Brunauer-Emmett-Teller tests and contact angles for water, which would further enhance the adsorption of polar contaminants on PVC-MP and thus increase the health risk of PVC-MP on aquatic organisms.

Original languageEnglish
Article number116082
JournalWater Research
Volume183
DOIs
Publication statusPublished - 2020 Sep 15

Keywords

  • Aging process
  • Dechlorination
  • Low-molecular-weight organic acid
  • Polyvinyl chloride microplastic
  • Reactive oxygen species

ASJC Scopus subject areas

  • Ecological Modelling
  • Water Science and Technology
  • Waste Management and Disposal
  • Pollution

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