Layered graphene oxide / nickel hydroxide nanosheet membranes with superior Na+ blocking and water permeation properties

Abstract Graphene oxide (GO) membranes contain numerous oxygen-based functional groups and so exhibit high water permeability and could potentially be used for desalination. However, the negative charge of the GO permits the migration of cations such as Na⁺, necessitating structural modifications to improve ion selectivity. In this study, positively charged nickel hydroxide nanosheets were stacked onto GO membranes to create a layered structure with 2 faces. The resulting layered membrane demonstrated an exceptionally low Na⁺ permeation rate and exhibited a water/Na⁺ permeation ratio approximately 7 times higher than that of a pure GO membrane.