Key Laboratory of Northwest Water Resource, Environment and Ecology, MOE, Xi'an University of Architecture and Technology, Xi'an 710055, China; Shaanxi Key Laboratory of Environmental Engineering, Xi'an University of Architecture and Technology, Xi'an 710055, China.
Key Laboratory of Northwest Water Resource, Environment and Ecology, MOE, Xi'an University of Architecture and Technology, Xi'an 710055, China; Shaanxi Key Laboratory of Environmental Engineering, Xi'an University of Architecture and Technology, Xi'an 710055, China.
J Hazard Mater. 2023 Aug 5;455:131636. doi: 10.1016/j.jhazmat.2023.131636. Epub 2023 May 13.
The characteristics and fates of microplastics (MPs) and humic acid (HA) in the environment are significantly influenced by their interactions. Thus, the influence of the MP-HA interaction on their dynamic characteristics was explored. Upon MP-HA interaction, the number of hydrogen bonds established in the HA domains decreased significantly, and the water molecules bridging the hydrogen bonds shifted to the exterior regions of the MP-HA aggregates. The distribution intensity of Ca located at ∼0.21 nm around HA deceased, indicating that the coordination of Ca with the carboxyl on HA was impaired in the presence of MPs. Additionally, the Ca-HA electrostatic interaction was suppressed because of the steric hindrance of the MPs. However, the MP-HA interaction improved the distribution of water molecules and metal cations around the MPs. The diffusion coefficient of HA decreased from 0.34 × 10 cm/s to 0.20-0.28 × 10 cm/s in the presence of MPs, implying that the diffusion of HA was retarded. The diffusion coefficients of polyethylene and polystyrene increased from 0.29 × 10 cm/s and 0.18 × 10 cm/s to 0.32 × 10 cm/s and 0.22 × 10 cm/s, respectively, indicating that the interaction with HA accelerated the migration of polyethylene and polystyrene. These findings highlight the potential environmental hazards posed by MPs in aquatic environments.
微塑料（MPs）和腐殖酸（HA）在环境中的特性和命运受其相互作用的显著影响。因此，研究了 MP-HA 相互作用对其动态特性的影响。MP-HA 相互作用后，HA 域中形成的氢键数量显著减少，桥接氢键的水分子迁移到 MP-HA 聚集体的外部区域。位于 HA 周围约 0.21nm 的 Ca 的分布强度降低，表明在 MPs 存在的情况下，Ca 与 HA 上的羧基的配位受到损害。此外，由于 MPs 的空间位阻，Ca-HA 静电相互作用受到抑制。然而，MP-HA 相互作用改善了水分子和金属阳离子在 MPs 周围的分布。HA 的扩散系数从 0.34×10 cm/s 降低到 0.20-0.28×10 cm/s 存在 MPs 时，表明 HA 的扩散受到阻碍。聚乙烯和聚苯乙烯的扩散系数分别从 0.29×10 cm/s 和 0.18×10 cm/s 增加到 0.32×10 cm/s 和 0.22×10 cm/s，表明与 HA 的相互作用加速了聚乙烯和聚苯乙烯的迁移。这些发现强调了 MPs 在水生环境中可能带来的潜在环境危害。
