State Key Laboratory of Pollution Control and Resource Reuse, School of the Environment, Nanjing University, Nanjing 210023, PR China.
State Key Laboratory of Pollution Control and Resource Reuse, School of the Environment, Nanjing University, Nanjing 210023, PR China; Quanzhou Institute for Environmental Protection Industry, Nanjing University, Beifeng Road, Quanzhou 362000, PR China.
Sci Total Environ. 2022 Dec 1;850:157829. doi: 10.1016/j.scitotenv.2022.157829. Epub 2022 Aug 4.
Microplastic (MP) pollution has increasingly become an enormous global challenge due to the ubiquity and uncertain environmental performance, especially for nano- and micro- sized MPs. In this work, the performance and mechanisms in coagulation of 100 nm-5.0 μm sized polystyrene particles using an etherified starch-based coagulant (St-CTA) assisted by polysilicic acid (PSA) were systematically studied on the basis of the changes in MPs removal rates under various pH levels and in the presence of different coexisting inorganic and organic substances, zeta potentials of supernatants, and floc properties. St-CTA in conjunction with PSA had a high performance in coagulation of nano- and micro- sized MPs from water with a lower optimal dose and larger and compacter flocs. Besides, the MPs removal rate can be improved in acidic and coexisting salt conditions. The efficient performance in removal of MPs by this enhanced coagulation was owing to the synergic effect, that is, the effective aggregation of MPs through the charge neutralization of St-CTA followed by the efficient netting-bridging effect of PSA. The effectiveness of this enhanced coagulation was further confirmed by removal of two other typical nano-sized MPs, such as poly(methyl methacrylate) and poly(vinyl chloride), from different water sources including tap water, river water, and sludge supernatant from a sewage treatment plant. This work provided a novel enhanced coagulation technique that can effectively remove nano- and micro- sized MPs from water.
由于微塑料（MP）无处不在且其环境性能不确定，微塑料污染已日益成为一个全球性的巨大挑战，尤其是对于纳米和微米级别的微塑料而言。在这项工作中，基于 MPs 去除率在不同 pH 值条件下以及不同共存无机和有机物质、上清液的 ζ 电位和絮体特性变化的情况下，系统研究了使用基于醚化淀粉的凝聚剂（St-CTA）和多硅酸（PSA）辅助凝聚 100nm-5.0μm 尺寸的聚苯乙烯颗粒的性能和机制。St-CTA 与 PSA 结合在低最佳剂量和更大、更紧凑的絮体的条件下对水中的纳米和微米级 MPs 具有高效的凝聚性能。此外，在酸性和共存盐条件下，MPs 的去除率可以提高。这种强化混凝去除 MPs 的高效性能归因于协同作用，即通过 St-CTA 的电荷中和有效聚集 MPs，然后通过 PSA 的有效网捕桥联效应。该强化混凝的有效性通过从自来水、河水和污水处理厂污泥上清液等不同水源中去除另外两种典型的纳米级 MPs（如聚甲基丙烯酸甲酯和聚氯乙烯）得到了进一步证实。这项工作提供了一种新型的强化混凝技术，可以有效地从水中去除纳米和微米级别的 MPs。
