Sorption of Pollutants on Microplastics

Abstract

This chapter presents the different aspects involved in the study of pollutant sorption on microplastics (MPs). Introductory descriptions of the sorption processes are presented. The study of sorption capacity at equilibrium and kinetics is important to better understand the process. Early studies recognized the presence of chemicals on the MPs, and there are several of them performed throughout the world. These studies demonstrated that the presence of many chemicals found on MPs is due to sorption while in contact with polluted seawater. Later studies performed laboratory experiments and field studies to better understand sorption processes. In the case of polyethylene (PE), which is the major polymer of MPs found at sea, hydrophobic linear sorption is the main mechanism. However, polar compounds seem to sorb more on PE once it has polar functional groups on its surface that can be formed due to degradation or the development of biofilm. There are many studies that focus on these different aspects of sorption, but there are still several challenges related to studying sorption on MPs. These challenges are related to the existing analytical techniques that limit the size of MPs to be observed and handled during experiments. These create difficulties in order to perform highly relevant studies.