Selective solvent and solute transport across nanopores is fundamental to membrane separations, yet it remains poorly understood, especially for non-aqueous systems. Here, we design a chemically robust nanoporous graphene membrane and study molecular transport in various organic liquids under subnanometre confinement. We show that the nature of the solvent can modulate solute diffusion across graphene nanopores, and that breakdown of continuum flow occurs when pore size approaches the solvent’s smallest molecular cross-section. By holistically engineering membrane support, modelling pore creation and defect management, high rejection and ultrafast organic solvent nanofiltration of dye molecules and separation of hexane isomers are achieved. The membranes exhibit stable fluxes across a range of solvents, consistent with flow across rigid pores whose size is independent of the solvent. These results demonstrate that nanoporous graphene is a rich materials system for controlling subcontinuum flow that could enable new membranes for a range of challenging separation needs.

跨纳米孔的选择性溶剂和溶质传输是膜分离的基础，但人们对其了解甚少，尤其是对于非水系统。在这里，我们设计了一种化学坚固的纳米多孔石墨烯膜，并研究了亚纳米限制下各种有机液体中的分子传输。我们表明，溶剂的性质可以调节溶质在石墨烯纳米孔中的扩散，并且当孔径接近溶剂的最小分子横截面时，会发生连续流的分解。通过整体设计膜支撑、模拟孔隙产生和缺陷管理，实现了染料分子的高截留率和超快有机溶剂纳滤以及己烷异构体的分离。膜在一系列溶剂中表现出稳定的通量，与穿过大小与溶剂无关的刚性孔隙的流动一致。这些结果表明，纳米多孔石墨烯是一种用于控制亚连续流的丰富材料系统，可以使新膜满足一系列具有挑战性的分离需求。