Investigation of heavy metal adsorption on microplastics

Keywords: Microplastics, Heavy metal, Adsorption, Kinetics of Adsorption, Adsorption Isotherms Microplastics and heavy metals represent two pollutant classes having negative effects on aquatic ecosystems. Living creatures in aquatic ecosystems can easily swallow the microplastics in waters. In this way, microplastics cause pollutants to be transferred through the food chain. And they indirectly become a threat for the health of surrounding creatures. The aim of this study is to analyze role of the microplastics as a vector for heavy metals. For this aim, adsorption of two heavy metals [Lead (Pb)II and Aluminium (Al)III on three different type of microplastics [polyethylene tereftalat (PET), polyamide (PA), ethylene vinyl acetate (EVA)] has been researched. The analysis of Scanning Electron Microscopy (SEM) shows that the microplastics have different surface characteristics. The effects of parameters like pH degree of adsorbate solution, contact time, initial concentration and temperature on adsorption capacity have been experimentally analyzed. In order to clarify adsorption mechanism, Langmuir and Freundlich adsorption isotherm models have been applied and Freundlich model has been seen more suitable than Langmiur model. In addition, kinetic parameters representing adsorption time have been calculated. Imaginary-second kinetic model has been seen more suitable than imaginary-first model. Adsorption percentages have been observed to change according to microplastics type and study conditions. In conclusion, microplastics cause heavy metals to join food chain and potentially act as a means for bioaccumulation of them.