Removal of polystyrene nanoplastics in multisolute systems with metallic contaminants using magnetic particles

Although microplastics (MPs) pollution is a major-global concern, knowledge of the complexity of interactions between nanoplastics (NPs) and other aquatic components in a multisolute system is limited. In this study, the accumulation and detachment of polystyrene NPs (PNPs) via magnetic particles (MA) in multisolute solutions were investigated. The results demonstrated that the adsorption affinity of MA for PNPs in the presence of metal ions is visibly higher than that of PNPs alone, which can be attributed to the complex formation among MA–PNPs–metal ions. The concentration of metal ions and their physicochemical properties as well as the functional groups of MA influence adhesion. The formation of metal ions-mediated complexes on MA is promoted at higher ionic strength, and the polyvalent electrolyte, humic acid, and pH significantly affect the aggregation of PNPs in the multisolute system containing metal ions. The observation of two-dimensional correlation spectroscopy indicated that the order of functional groups in the process of capturing PNPs differs according on the type of metal ion. As a result, the findings show that the ability of MA to uptake and transport NPs is enhanced under the presence of metallic pollutants, which has shifted current perspectives on the environmental fate and the adverse effects of NPs in highly heterogeneous aquatic systems.