Assessment of the sorption capacity of PET microparticles in natural water with respect to metals

Contamination of the World Oceans with microplastics (MPs) is one of the most discussed environmental problems of the last decade. MPs are able to accumulate on their surface pollutants present in water in very low concentrations. Concentrations of pollutants, such as metals, can reach values that exceed the natural background in water bodies.Thus, MPs can act as a secondary source of contamination of water bodies with metals.The sorption capacity of artificially grinded and aged in the natural environment microparticles of polyethylene terephthalate (PET) with respect to metals in the natural water of Lake Onego was assessed in laboratory conditions.The Total Content method was used to characterize the sorption process and to obtain the dependence of the concentration of a substance in the stationary phase on its concentration in the mobile phase (experimental sorption isotherms were obtained). Subsequent mathematical processing of the experimentally obtained metal sorption isotherms on PET for Mn, Ni, Cu, Cd, and Pb allowed us to determine the monolayer capacities, adsorption equilibrium constants, and adsorption values at the equilibrium adsorbate concentration for each of the studied metals. This information is valuable to assess the role of MPs in metals transport in water bodies. The study was supported by the Russian Science Foundation grant number 19-17-00035.