The coagulation behavior and removal efficiency of microplastics in drinking water treatment

As a kind of emerging contaminants, microplastics (MPs) have got great attention due to its worldwide distribution, ecotoxicology and difficult to remove. MPs have already been found in the drinking water because of its low removal efficiency during drinking water treatment. As an important process to remove the particles in water, the coagulation behavior of MPs with different characteristics is still not clear. Besides that, research about the removal of MPs by coagulation is on the initial stage and the results are not consistent. This article studied on the MPs which were hard to be removed during the coagulation by conventional coagulation methods during the drinking water treatment, aimed to found the influence of MPs characteristics on the coagulation behavior, explore the removal efficiency of MPs under optimal coagulation conditions and infer the coagulation mechanisms of MPs. According to the results of this article, size and concentration of MPs both had significant effect on the coagulation, but the size of MPs was the main impact factor, and the category of MPs had no significant effect on the coagulation. After operating condition optimization, the removal efficiency of MPs with size ≥13 μm could reach >70 % by PAC and PAM. During coagulation process, electrical neutralization of PAC played the most important role, the adsorption bridging and net sweeping of PAM could assistant the coagulation.