| Abstract | Microplastics can cause many problems to the marine and freshwater environments. They have plenty of surface area, high hydrophobic ability, and great approach to interact with microorganisms. With those properties, pollutants and contaminants could be attached by microplastics and/or be carried on their surface. From these reasons, microplastics and their attached pollutants can be distributed around the world, and causing complex toxic compounds or substances to the aquatic living animals, and transmitted along throughout the food chain. This research study aims to quantify the adsorption capacity of metals, chromium (Cr), copper (Cu), and lead (Pb), on different microplastics types, polypropylene (PP) and polystyrene (PS), and to compare and analyze the adsorption behavior and kinetic mechanism of metals in freshwater environment. The freshwater was sampled at 14:00 hours on the 21st of May 2021 at the canal between the AIT Library and School of Environment, Resources and Development (SERD) in Asian Institute of Technology, Thailand. The water properties, temperature, pH, EC, TDS, salinity, and resistivity were 29.5 °C, 6.43, 500.9 µS/cm, 250.4 mg/L, 0.24 ppt, and 1997 Ω, respectively. In addition, the metal contents of chromium, copper, and lead in freshwater sample were 18.38, 11.14, <5.00 µg/L. The adsorption efficiency of metals on microplastics particles were sorted from most to least as copper, lead, and chromium, respectively. And more metal contents could adsorb on polystyrene more than on polypropylene. The adsorption behavior in this research study experiment in 12-day period was similar with the pseudo first order of kinetic model. The adsorption time which reached the equilibrium is tentatively 7-day time or a few days after 7-day time. |