Guangdong Provincial Research Center for Environment Pollution Control and Remediation Materials, College of Life Science and Technology, Jinan University, Guangzhou, 510632, China.
Guangdong Provincial Research Center for Environment Pollution Control and Remediation Materials, College of Life Science and Technology, Jinan University, Guangzhou, 510632, China.
Environ Pollut. 2024 Oct 15;359:124758. doi: 10.1016/j.envpol.2024.124758. Epub 2024 Aug 16.
Due to the extensive use of plastic products and unreasonable disposal, nanoplastics contamination has become one of the important environmental problems that mankind must face. The composition and structure of porous media can determine the complexity and diversity of the transport behavior of nanoplastics. In this study, the influence of diatomite (DIA) on the nanoplastics transport in porous media is investigated by column experiments combined with XDLVO interaction energy and transport model. Results suggest that the recovery rates of unmodified polystyrene nanoparticles (PSNPs) and carboxyl-modified polystyrene nanoparticles (PSNPs-COOH) in the porous media containing DIA decreases compared with that in the pure quartz sand (QS), and the BTCs showed a "blocking" pattern. The presence of DIA inhibits the transport of both PSNPs and PSNPs-COOH, but the inhibition is not significant. This may be because the presence of DIA provides more favorable deposition sites for PSNPs and PSNPs-COOH to some extent. However, since DIA itself carries a certain negative charge, this can only play a role in compressing the double electric layer for PSNPs and PSNPs-COOH with the same negative charge, and cannot destabilize them. The migration capacity of PSNPs and PSNPs-COOH is strongest in the DIA-QS porous media at pH = 7, and is weak at pH = 9 and pH = 5. The inhibition of migration at pH = 9 can be attributed to the dissolution of the DIA surface under alkaline conditions and the formation of pore and defect structures, which provide more deposition sites for PSNPs and PSNPs-COOH. The presence of humic acid (HA) leads to an increase in the mobility of PSNPs and PSNPs-COOH, and the mobility is enhanced with HA concentration. The mobility of PSNPs and PSNPs-COOH in DIA-QS decreases with ionic valence and ionic strength, and PSNPs-COOH is more significantly inhibited compared to PSNPs.
由于塑料制品的广泛使用和不合理处置，纳米塑料污染已成为人类必须面对的重要环境问题之一。多孔介质的组成和结构可以决定纳米塑料迁移行为的复杂性和多样性。本研究通过柱实验结合 XDLVO 相互作用能和迁移模型，考察了硅藻土（DIA）对多孔介质中纳米塑料迁移的影响。结果表明，与纯石英砂（QS）相比，含有 DIA 的多孔介质中未改性聚苯乙烯纳米颗粒（PSNPs）和羧基改性聚苯乙烯纳米颗粒（PSNPs-COOH）的回收率降低，BTC 呈现“堵塞”模式。DIA 的存在抑制了 PSNPs 和 PSNPs-COOH 的迁移，但抑制作用不明显。这可能是因为 DIA 的存在在一定程度上为 PSNPs 和 PSNPs-COOH 提供了更有利的沉积位置。然而，由于 DIA 本身带有一定的负电荷，这只能对带相同电荷的 PSNPs 和 PSNPs-COOH 的双电层起到压缩作用，而不能使其不稳定。在 pH = 7 的 DIA-QS 多孔介质中，PSNPs 和 PSNPs-COOH 的迁移能力最强，在 pH = 9 和 pH = 5 时较弱。在 pH = 9 时迁移受到抑制可归因于碱性条件下 DIA 表面的溶解以及孔和缺陷结构的形成，这为 PSNPs 和 PSNPs-COOH 提供了更多的沉积位置。腐殖酸（HA）的存在会增加 PSNPs 和 PSNPs-COOH 的迁移能力，且随着 HA 浓度的增加而增强。PSNPs 和 PSNPs-COOH 在 DIA-QS 中的迁移能力随离子价和离子强度的增加而降低，且 PSNPs-COOH 的抑制作用比 PSNPs 更明显。
