Microplastic (MP) is considered as one of the emerging pollutants in marine environments. Because of low density and small particle size (<5 mm), MPs are easily discharged into open waterways by stormwater runoff. Therefore, the aim of this study was to investigate the effect of coagulation process for the removal of different types of MPs such as low-density polyethylene (LDPE), high-density polyethylene (HDPE) and polypropylene (PP) from synthetic stormwater. The effect of different types of a coagulant such as alum and polyacrylamide (PAM), dosages of coagulants, solution pH and weathering conditions was investigated for the removal of MPs. Results found that a combination of alum and PAM performed better than standalone coagulant for MPs removal. The removal of all three types of MPs was high at low pH (3–5). It is also found that the removal efficiency of LDPE, HDPE and PP was 92 %, 84 % and 96 %, respectively under the weathering conditions. The mechanisms for MP removal were charge neutralization and hydrophobic interaction between MP and coagulant flocs. Overall, this study has confirmed that the coagulation process was very effective for removing MP particles under weathering conditions.

微塑料（MP）被认为是海洋环境中的新兴污染物之一。由于低密度和小粒径（<5 mm），MPs 很容易被雨水径流排放到开阔的水道中。因此，本研究的目的是研究混凝过程对从合成雨水中去除不同类型 MPs 如低密度聚乙烯 (LDPE)、高密度聚乙烯 (HDPE) 和聚丙烯 (PP) 的影响。研究了不同类型的混凝剂如明矾和聚丙烯酰胺 (PAM)、混凝剂的剂量、溶液 pH 值和风化条件对去除 MP 的影响。结果发现，明矾和 PAM 的组合在去除 MPs 方面的性能优于单独的混凝剂。在低 pH (3-5) 下，所有三种类型的 MP 的去除率都很高。还发现，在风化条件下，LDPE、HDPE 和 PP 的去除效率分别为 92%、84% 和 96%。MP 去除的机制是电荷中和和 MP 与絮凝剂絮凝剂之间的疏水相互作用。总的来说，这项研究已经证实混凝过程对于在风化条件下去除 MP 颗粒非常有效。