Key Laboratory of Drinking Water Science and Technology, Research Centre for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing, 100085, PR China; Section of Sanitary Engineering, Department of Water Management, Faculty of Civil Engineering and Geosciences, Delft University of Technology, Stevinweg 1, 2628 CN Delft, The Netherlands.
Key Laboratory of Drinking Water Science and Technology, Research Centre for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing, 100085, PR China; University of Chinese Academy of Sciences, Beijing, China.
Water Res. 2022 Nov 1;226:119313. doi: 10.1016/j.watres.2022.119313. Epub 2022 Oct 31.
The transport and fate of nanoplastics (NPs) in aquatic environments are closely associated with their colloidal stability, which is affected by aging and natural organic matter (NOM) adsorption. This study systematically investigated the combined effects of photoaging and NOM (e.g. humic acids, HA; and a model protein, bovine serum albumin, BSA) on the aggregation kinetics of NPs (polystyrene, PS) in NaCl and CaCl solutions. Our results showed that photoaged NPs adsorbed less HA than pristine NPs due to weaker hydrophobic and π-π interactions. In return, HA showed weaker impacts on NPs' stability after photoaging. Differently, photoaged NPs absorbed more BSA than pristine NPs due to stronger hydrogen bonding and electrostatic attraction. Thus, the inhibitory effects of BSA on the aggregation kinetics of NPs were enhanced after photoaging. Regarding the effects of NOM on the aging of NPs, our results showed that HA competed with NPs for photons and underwent photo-degradation. Subsequently, the destruction/reconstruction of adsorbed HA increased (in NaCl) or decreased (in CaCl) the stability of NPs. Notably, light radiation-induced flocculation of BSA molecules, which wrapped and integrated NPs and lead to their destabilization. Overall, this study provided new insights into the aggregation behavior of NPs in aquatic systems, which have significant implications for predicting the transport and fate of NPs in complex real-world environments.
纳米塑料（NPs）在水环境中的迁移和归宿与其胶体稳定性密切相关，而胶体稳定性又受到老化和天然有机物（NOM）吸附的影响。本研究系统研究了光老化和 NOM（如腐殖酸，HA；和一种模型蛋白，牛血清白蛋白，BSA）对 NPs（聚苯乙烯，PS）在 NaCl 和 CaCl 溶液中聚集动力学的联合影响。结果表明，由于疏水性和π-π相互作用较弱，光老化 NPs 比原始 NPs 吸附的 HA 更少。相反，HA 对光老化后 NPs 稳定性的影响较弱。不同的是，由于更强的氢键和静电吸引，光老化 NPs 比原始 NPs 吸附更多的 BSA。因此，BSA 对 NPs 聚集动力学的抑制作用在光老化后增强。关于 NOM 对 NPs 老化的影响，我们的结果表明，HA 与 NPs 竞争光子并经历光降解。随后，吸附的 HA 的破坏/重构增加（在 NaCl 中）或减少（在 CaCl 中）了 NPs 的稳定性。值得注意的是，光辐射诱导 BSA 分子絮凝，从而包裹和整合 NPs 并导致其失稳。总的来说，本研究为预测 NPs 在复杂实际环境中的迁移和归宿提供了新的见解。
