Graphene oxide (GO) membranes have shown great potential in ionic sieving from aqueous solutions. However, it remains challenging for GO membranes to exclude small ions with a large water flux. Herein, organic ions are confined onto the GO interlaminations to form a precisely restricted 2D channel size of 0.71 nm, which presents >99.9% NaCl rejections and high freshwater fluxes via the pervaporation method, both being orders of magnitude higher than that of common GO membranes. Theoretical calculations reveal that, apart from controlling the 2D channel size of GO by strong cation–/anion–π and π–π interactions, the organic ions act as vapor traps to remarkably shorten vapor diffusion distance and then as water pumps to significantly enlarge water permeability. It not only theoretically explains the low permeability over the common GO membranes with large 2D channels, but also experimentally demonstrates fast and complete desalination on the organic ions-GO membrane.

氧化石墨烯 (GO) 膜在从水溶液中进行离子筛分方面显示出巨大的潜力。然而，对于 GO 膜来说，排除具有大水通量的小离子仍然具有挑战性。在此，有机离子被限制在 GO 层间以形成 0.71 nm 的精确限制的 2D 通道尺寸，通过渗透蒸发方法呈现 >99.9% 的 NaCl 截留和高淡水通量，两者都比普通 GO 膜高几个数量级. 理论计算表明，除了通过强阳离子-/阴离子-π 和 π-π 相互作用控制 GO 的二维通道尺寸外，有机离子作为蒸汽陷阱显着缩短蒸汽扩散距离，然后作为水泵显着扩大水渗透性。