Kim Min-Ji, Herchenova Yuliia, Chung Jaeshik, Na Sang-Heon, Kim Eun-Ju
Water Cycle Research Center, Korea Institute of Science and Technology (KIST), Seoul 02792, South Korea.
Water Cycle Research Center, Korea Institute of Science and Technology (KIST), Seoul 02792, South Korea; Division of Energy and Environment Technology, KIST School, University of Science and Technology, Seoul 02792, South Korea.
Water Res. 2022 Nov 1;226:119286. doi: 10.1016/j.watres.2022.119286. Epub 2022 Oct 22.
In this study, the aggregation behavior of polystyrene nanoplastics (PS NPs) in the absence or presence of oppositely charged particulate matters is systematically investigated for a wide range of electrolyte conditions. Herein, we used isothermal titration calorimetry combined with time-resolved dynamic light scattering to provide kinetic and thermodynamic insights into the NP aggregation. The thermodynamic profiles of homoaggregation and heteroaggregation were fit using an independent site and two independent sites models, respectively, demonstrating different interaction modes of both aggregation processes. We found that the contribution of solvation entropy was significant and variable in most cases, and this thermodynamic parameter was a large determinant of the thermodynamics of NP aggregation. Furthermore, the stability of PS NPs in natural water matrices was found to be correlated with ionic strength and the content of natural colloids (e.g., metal oxides and clay particles). These results point to the importance of considering the role of thermodynamic variables when studying the fate of NPs within various environmental conditions.
在本研究中，我们系统地研究了在广泛的电解质条件下，聚苯乙烯纳米塑料（PS NPs）在不存在或存在带相反电荷的颗粒物时的聚集行为。在此，我们使用等温滴定量热法结合时间分辨动态光散射，以提供关于纳米颗粒聚集的动力学和热力学见解。均相聚集和异相聚集的热力学曲线分别使用独立位点模型和两个独立位点模型进行拟合，这表明了两种聚集过程的不同相互作用模式。我们发现，在大多数情况下，溶剂化熵的贡献显著且可变，并且该热力学参数是纳米颗粒聚集热力学的一个重要决定因素。此外，发现PS NPs在天然水基质中的稳定性与离子强度和天然胶体（如金属氧化物和粘土颗粒）的含量相关。这些结果表明，在研究纳米颗粒在各种环境条件下的归宿时，考虑热力学变量的作用非常重要。
