Effect of molecular dynamics water models on flux, diffusivity, and ion dynamics for polyamide membrane simulations
Effect of molecular dynamics water models on flux, diffusivity, and ion dynamics for polyamide membrane simulations
复制标题
分子动力学水模型对聚酰胺膜模拟的通量、扩散率和离子动力学的影响
DOI：
10.1016/j.memsci.2023.121630
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发表时间：
2023
影响因子：
9.5
通讯作者：
Lueptow, Richard M.
中科院分区：
文献类型：
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作者：
Liu, Suwei;Keten, Sinan;Lueptow, Richard M.
尽管反渗透(RO)和纳滤(NF)膜的分子动力学(MD)模型对研究水过滤过程是有用的，但特定的水模型和力场参数对通量和扩散系数等关键指标有着深远的影响。此外，与系综相关的参数，如温度以及如何通过恒温器控制温度，也会影响模拟结果。为了量化这些影响，我们研究了三种常用的水模型SPC/E、TIP3P和TIP4P在不同温度和恒温器设置下模拟纳滤膜系统的性能。这三个水模型都成功地捕捉到了水的扩散系数与温度之间的Arrhenius关系，以及通过膜的水通量与膜内的水扩散系数之间的线性关系。然而，与实验相比，SPC/E低估了，TIP3P高估了，而TIP4P最准确地再现了水的动态，特别是水的自扩散系数。我们还考察了水模型对不同浓度的普通盐溶液的影响。在描述离子扩散系数和离子周围的水溶剂化壳层时，TIP4P通常优于其他两个水模型。这些结果表明，TIP4P是一种适用于聚酰胺膜分子动力学模拟的水模型。
While molecular dynamics (MD) models for reverse osmosis (RO) and nanofiltration (NF) membranes are useful for studying water filtration processes, the specific water model and force-field parameters have a profound impact on key measures such as flux and diffusivity. Moreover, ensemble related parameters such as temperature and how it is controlled via a thermostat also affect simulation results. To quantify these effects, we investigate the performance of three commonly used water models, SPC/E, TIP3P, and TIP4P, in simulating an NF membrane system at varying temperatures and thermostat settings. All three water models successfully capture the Arrhenius relationship between water diffusivity and temperature as well as the linear relationship between water flux through the membrane and water diffusivity in the membrane. However, SPC/E underpredicts, TIP3P overpredicts, and TIP4P most accurately reproduces the water dynamics, especially water self-diffusivity, compared to experiments. We also investigate the effect of the water model on common salt solutions at various concentrations. TIP4P generally outperforms the other two water models when describing ion diffusivities and water solvation shells around ions. These findings indicate that TIP4P is an appropriate water model to use in polyamide membrane MD simulations.