Department of Geology, 34962Kangwon National University, Chuncheon, Republic of Korea.
Sci Prog. 2023 Jan-Mar;106(1):368504221150430. doi: 10.1177/00368504221150430.
Nanoplastic pollution is an emerging environmental threat to the critical zone. The transport of nanoplastic particles in subsurface environments can be determined mainly by soil minerals because they provide surfaces that interact with nanoplastic particles. However, the interactions between mineral surfaces and nanoplastics are poorly understood. In this study, the deposition kinetics of polystyrene-nanoplastic particles onto representative oxide surfaces SiO and AlO at circumneutral pH were investigated using a quartz crystal microbalance, with variations in the ionic strength (0.1-100 mM) of the well-dispersed nanoplastic particles suspension. While polystyrene-nanoplastic particles deposited minimally on the SiO surface at an ionic strength of < 100 mM (∼10 ng/cm), substantial deposition occurred at 100 mM (3.7 ± 0.4 μg/cm). On the AlO surface, a significant amount of polystyrene-nanoplastic particle was deposited from the lowest ionic strength (4.5 ± 0.8 μg/cm. The deposition mass at 100 mM NaCl was two times higher (7.2 ± 0.2 μg/cm) than on the SiO surface, while the deposition rates were similar between the two surfaces (10-15 Hz/min). Our results indicate that alumina most likely exerts a stronger influence than quartz on the transport of nanoplastic particles in soils and groundwater aquifers. The deposition kinetics strongly depends on the mineral surface and solution ionic strength, and these quantitative results can serve as validation data in developing transport modeling of nanoplastic in subsurface environments.
纳米塑料污染是对关键带的一种新兴环境威胁。在地下环境中，纳米塑料颗粒的迁移主要取决于土壤矿物质，因为矿物质表面为纳米塑料颗粒提供了相互作用的场所。然而，矿物质表面与纳米塑料之间的相互作用还了解甚少。在这项研究中，使用石英晶体微天平研究了在中性 pH 值下，代表性氧化物表面 SiO 和 AlO 上的聚苯乙烯纳米塑料颗粒的沉积动力学，其中纳米塑料颗粒悬浮液的离子强度（0.1-100 mM）发生变化。虽然在离子强度<100 mM（约 10 ng/cm）时，聚苯乙烯纳米塑料颗粒在 SiO 表面上的沉积量很少（∼10 ng/cm），但在 100 mM 时却大量沉积（3.7 ± 0.4 μg/cm）。在 AlO 表面上，即使在最低离子强度（4.5 ± 0.8 μg/cm）下，也有大量的聚苯乙烯纳米塑料颗粒沉积。在 100 mM NaCl 下的沉积量比在 SiO 表面上高两倍（7.2 ± 0.2 μg/cm），而两个表面上的沉积速率相似（10-15 Hz/min）。我们的结果表明，氧化铝对土壤和地下含水层中纳米塑料颗粒迁移的影响很可能比石英更强。沉积动力学强烈依赖于矿物质表面和溶液离子强度，这些定量结果可作为开发地下环境中纳米塑料迁移的运输建模的验证数据。
