Nanostructured Graphene Oxide Composite Membranes with Ultra-permeability and Mechanical Robustness.

Graphene oxide (GO) membranes have great potential due to their low-friction water permeation combined with unique molecular sieving ability. However, the practical use of deposited GO membranes is limited by the inferior mechanical robustness in the composite structure derived from conventional deposition methods. Here, we report a nanostructured GO membrane that possesses great permeability and mechanical robustness. This composite membrane containing an ultrathin selective GO nanofilm (as low as 32 nm thick) and a post-synthesized macroporous support layer exhibits excellent stability in water and under practical permeability testing. With precise optimizations in both selective and support layers, unprecedented water permeability (47 liters m-2 hr-1 bar-1) and high retention (>98% of solutes with hydrated radii larger than 4.9 Å) were obtained.