Environmental Co-existence of Microplastics and Perfluorochemicals: A Review of Their Interactions

The co-existence of microplastics and perfluorochemicals in the environment has raised concern about their potential interactions, which could complicate their ecotoxicity. This article aims to review the interactions between microplastics and perfluorochemicals in the environment, particularly the mechanisms of interactions and the factors affecting the interactions. It reviewed more than 40 scholarly articles published in the past five years. Thematic analysis was performed on the articles to extract the related information. The review highlights that owing to the structures of perfluorochemicals consisting of hydrophobic moieties and charged functional groups, as well as the surface chemistry of microplastics, the main mechanisms governing the interactions are hydrophobic interactions, hydrogen bonding and electrostatic interactions, with some pore-filling. The interactions are primarily sorption, with adsorption being predominant. Adsorption of perfluorochemicals onto microplastics is generally positively correlated with the carbon chain lengths of perfluorochemicals. However, it is also affected by the functional groups of perfluorochemicals, the types and sizes of microplastics, as well as environmental factors comprising pH, ionic strength, concentrations of organic matter, and the presence of other contaminants. This review provides crucial insight into the interactions between the two pervasive pollutants to permit better characterization of their risk and ecotoxicity in different environments.