Abstract Forward osmosis (FO) has proven to be a promising membrane separation technology for seawater desalination. However, advanced porous membranes are highly demanded to improve the efficiency of FO process. The single-layer C2N, also known as nitrogenated holey graphene, has recently emerged as a promising material for nanofiltration due to its intrinsic porous structure and robust mechanical strength. In this study, molecular dynamics simulations have been conducted to investigate the seawater desalination performance of the single-layer C2N membrane in the FO process by tuning its pore size using tensile strain. The results show that with a biaxial tensile strain larger than 4%, the C2N membrane becomes permeable to the water molecules but completely impermeable to the salt ions. At the strain of 12%, a water flux as high as 14.36 L cm−2 h−1 can be obtained at the moderate temperature of 338 K. Interestingly, the permeation water flux shows a nonmonotonic dependence on the osmosis pressure difference across the membrane. To understand the underlying mechanism, the potential mean force profile, water density distribution and hydrogen bonding dynamics are analyzed to investigate both the diffusion of the water molecules near the membrane and in the bulk salt solution. This study is helpful for the understanding of the water permeation behavior through the C2N membrane and promoting its application in seawater desalination.

中文翻译：

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用于通过正向渗透进行有效海水淡化的应变单层 C 2 N 膜：分子动力学研究

摘要 正渗透（FO）已被证明是一种很有前途的海水淡化膜分离技术。然而，非常需要先进的多孔膜来提高 FO 工艺的效率。单层 C2N，也称为氮化多孔石墨烯，由于其固有的多孔结构和强大的机械强度，最近已成为一种有前途的纳滤材料。在这项研究中，已经进行了分子动力学模拟，通过使用拉伸应变调整其孔径来研究单层 C2N 膜在 FO 过程中的海水淡化性能。结果表明，当双轴拉伸应变大于 4% 时，C2N 膜变得可渗透水分子但完全不能渗透盐离子。在 12% 的应变下，水通量高达 14。在 338 K 的适中温度下可以获得 36 L cm-2 h-1。有趣的是，渗透水通量显示出对跨膜渗透压差的非单调依赖性。为了了解潜在的机制，我们分析了潜在的平均力分布、水密度分布和氢键动力学，以研究膜附近和大量盐溶液中水分子的扩散。该研究有助于了解C2N膜的水渗透行为，促进其在海水淡化中的应用。分析了潜在的平均力分布、水密度分布和氢键动力学，以研究水分子在膜附近和大量盐溶液中的扩散。该研究有助于了解C2N膜的水渗透行为，促进其在海水淡化中的应用。分析了潜在的平均力分布、水密度分布和氢键动力学，以研究水分子在膜附近和大量盐溶液中的扩散。该研究有助于了解C2N膜的水渗透行为，促进其在海水淡化中的应用。