Sorption and desorption of organic UV filters onto microplastics in single and multi-solute systems

Wai Kit Ho, Kelvin S Y Leung*

*Corresponding author for this work

Research output: Contribution to journalJournal articlepeer-review

40 Citations (Scopus)


Sorption studies of organic pollutants by microplastics (MPs) in single-solute systems are well established in the literature. However, actual aquatic environments always contain a mixture of contaminants. Prediction of the fate and biological effects of MPs-mediated chemical exposure requires a better understanding of sorption-desorption processes of multiple organic contaminants by MPs. In this study, the altered sorption and desorption behaviors of individual organic UV filters (BP-3 and 4-MBC) in the presence of cosolutes (BP-3, 4-MBC, EHMC and OC) on two types of MPs (LDPE and PS) were examined. In most cases, co-occurrence of other organic UV filters appeared to have an antagonistic effect on the sorption of primary solute, which was consistent with trends found in previous studies. Nevertheless, the sorption uptake of 4-MBC as primary solute on PS was enhanced in the presence of cosolute(s), arising presumably from solute multilayer formation caused by laterally attractive π-π interactions between adsorbed cosolute(s) and 4-MBC molecules. Such formation of multilayer sorption in multi-solute systems depends on the solute hydrophobicity and concentration as well as inherent sorptivity of MPs. Our further desorption experiments revealed that the bioaccessibility of primary solute was significantly elevated with cosolutes, even though competitive sorption was observed under the same experimental conditions. These findings supplement the current knowledge on sorption mechanisms and interactions of multiple organic contaminants on MPs, which are critical for a comprehensive environmental risk assessment of both MPs and hazardous anthropogenic contaminants in natural environments.

Original languageEnglish
Article number113066
JournalEnvironmental Pollution
Publication statusPublished - Nov 2019

Scopus Subject Areas

  • Toxicology
  • Pollution
  • Health, Toxicology and Mutagenesis

User-Defined Keywords

  • Competitive interaction
  • Microplastic
  • Multi-solute system
  • Organic UV filter
  • Synergistic interaction


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