Graphene oxide (GO) membranes continue to attract intense interest due totheir unique molecular sieving properties combined with fast permeation rates.However, the membranes' use has been limited mostly to aqueous solutionsbecause GO membranes appear to be impermeable to organic solvents, a phenomenonnot fully understood yet. Here, we report efficient and fast filtration oforganic solutions through GO laminates containing smooth two-dimensional (2D)capillaries made from flakes with large sizes of ~ 10-20 micron. Withoutsacrificing their sieving characteristics, such membranes can be madeexceptionally thin, down to ~ 10 nm, which translates into fast permeation ofnot only water but also organic solvents. We attribute the organic solventpermeation and sieving properties of ultrathin GO laminates to the presence ofrandomly distributed pinholes that are interconnected by short graphenechannels with a width of 1 nm. With increasing the membrane thickness, theorganic solvent permeation rates decay exponentially but water continues topermeate fast, in agreement with previous reports. The application potential ofour ultrathin laminates for organic-solvent nanofiltration is demonstrated byshowing >99.9% rejection of various organic dyes with small molecular weightsdissolved in methanol. Our work significantly expands possibilities for the useof GO membranes in purification, filtration and related technologies.
展开▼
