Although coagulation is a well-known and widely used technique for removing suspended particles, there are no detailed data on its effectiveness in microplastic (MP) elimination. The research available on the removal of MPs by coagulation is at a preliminary stage and there is no research available on the mechanism and effectiveness of removal and the factors that increase the efficiency of elimination. A significant limitation of the research conducted so far on the coagulation process relative to MP elimination is the removal of only one type of MP, while in the environment, there is a mixture of particles differing primarily in composition but also in size and shape. The second limitation is ignoring the fact that microplastic particles present in environmental conditions are transformed/aged under the influence of abiotic and biotic factors. These particles then change not only their appearance, size/mass, or density but also their surface and chemical composition. These changes may have both positive and negative effects on the efficiency of microplastics elimination in the coagulation process.

The main goal of this article is to analyze the impact of biotic and abiotic aging of PE microplastics on the effectiveness of coagulation. The following aging methods are planned to be used: mechanical stress, thermal oxidation, UV aging, chemical treatments, and colonization by microorganisms.