The primary objective of this article is to develop a fundamental understanding of water/methanol and water/ethanol mixture permeation across microporous membrane constructs. Configurational-Bias Monte Carlo (CBMC) simulations were undertaken for water/methanol and water/ethanol mixture adsorption in all-silica zeolites (CHA, DDR, FAU, LTA) and ZIF-8. Additionally, Molecular Dynamics (MD) simulations were used to determine the intra-crystalline diffusivities in water/alcohol mixtures. The combination of CBMC and MD simulations allow the calculation of membrane permeation selectivities. This study provides insights into the influence of the structural properties of the microporous layer on the permeation selectivity. Another key result that emerges is that the water/alcohol permeation selectivity becomes increasingly in favor of water as the feed mixtures becomes richer in alcohol. The reason for the dependence can be traced to strong hydrogen bonding between water and alcohol molecular pairs resulting in cluster formation and enhanced water ingress; these results provide a rationalization of a number of membrane permeation studies in the literature. A corollary to the reported results is that the use of the Ideal Adsorbed Solution Theory (IAST) is unable to provide a quantitative description of mixture adsorption equilibrium and thermodynamic non-idealities need to be accounted for in modelling membrane permeation of water/alcohol mixtures.

中文翻译：

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对影响水/醇膜渗透选择性的各种因素的基本见解

本文的主要目的是对水/甲醇和水/乙醇混合物渗透微孔膜结构有一个基本的了解。对全硅沸石（CHA、DDR、FAU、LTA）和 ZIF-8 中的水/甲醇和水/乙醇混合物吸附进行构型偏倚蒙特卡罗 (CBMC) 模拟。此外，分子动力学（MD）模拟用于确定水/醇混合物中的晶内扩散率。 CBMC 和 MD 模拟的结合可以计算膜渗透选择性。这项研究深入了解了微孔层的结构特性对渗透选择性的影响。出现的另一个关键结果是，随着进料混合物中酒精含量的增加，水/酒精渗透选择性变得越来越有利于水。这种依赖性的原因可以追溯到水和醇分子对之间的强氢键，导致簇形成并增强水的进入；这些结果为文献中的许多膜渗透研究提供了合理化。所报告结果的推论是，理想吸附溶液理论（IAST）的使用无法提供混合物吸附平衡的定量描述，并且在模拟水/酒精混合物的膜渗透时需要考虑热力学非理想性。