College of Agricultural Science and Engineering, Hohai University, Nanjing 210098, China.
College of Agricultural Science and Engineering, Hohai University, Nanjing 210098, China.
Environ Pollut. 2024 Jan 15;341:123014. doi: 10.1016/j.envpol.2023.123014. Epub 2023 Nov 23.
Understanding the transport behaviors of microplastics (MPs) in porous media is crucial in controlling MPs pollution. Given nitrogen is one of the most important nutrients in soil and groundwater systems, unclearness of the transport behaviors of microplastics (MPs) under various nitrogen conditions may inhibit the acknowledgment of MPs fate. For this reason, this study innovatively investigates the transport characteristics of four kinds of typical MPs (PVC MPs, PMMA MPs, PET MPs, and PP MPs) under various NaNO, NHCl and urea conditions via column experiments numerical models. The FTIR and XPS analysis were conducted to excavate the transform of MPs. The MPs mobility was generally reduced with the increasing nitrogen concentrations. The polarity and density properties of different MPs played combined roles in transport under similar conditions. Compared to NO, NH may neutralize the negative charge of MPs and then restrain their transport in porous media. Urea may coat the surface of MPs and promote the mobility, however, increasing concentrations of urea may result in the interattraction between MPs and porous media via hydrogen-bond and π-π interaction. PET MPs and PP MPs showed barely transform during transport under the tested conditions. Particularly, the chlorines on PVC MPs could react with the amide on urea and produce amidogen, which may improve PVC MPs transport. The N-H and C-N bond also generated on PMMA MPs in presence of urea also may enhance the mobility.
了解微塑料（MPs）在多孔介质中的迁移行为对于控制 MPs 污染至关重要。鉴于氮是土壤和地下水系统中最重要的营养物质之一，因此在各种氮条件下微塑料（MPs）的迁移行为不明确可能会阻碍对 MPs 命运的认识。出于这个原因，本研究通过柱实验数值模型创新性地研究了四种典型 MPs（聚氯乙烯 MPs、聚甲基丙烯酸甲酯 MPs、聚对苯二甲酸乙二醇酯 MPs 和聚丙烯 MPs）在各种硝酸钠、氯化铵和尿素条件下的传输特性。通过傅里叶变换红外光谱（FTIR）和 X 射线光电子能谱（XPS）分析来挖掘 MPs 的转化。随着氮浓度的增加，MPs 的迁移性通常会降低。不同 MPs 的极性和密度特性在相似条件下共同作用于传输。与 NO 相比，NH 可能会中和 MPs 的负电荷，从而抑制其在多孔介质中的迁移。尿素可能会在 MPs 表面形成涂层，从而促进其迁移，但随着尿素浓度的增加，MPs 和多孔介质之间可能会通过氢键和π-π相互作用发生相互吸引。在测试条件下，PET MPs 和 PP MPs 在运输过程中几乎没有发生变化。特别是，PVC MPs 上的氯可以与尿素上的酰胺反应生成氨基，这可能会提高 PVC MPs 的迁移性。在尿素存在的情况下，PMMA MPs 上也会生成 N-H 和 C-N 键，这也可能会增强其迁移性。
