Tailoring the physicochemical and geometric properties of two-dimensional graphene membranes for aqueous separation

Two-dimensional (2D) graphene membranes have been a hotspot in the membrane area, owing to their unique 2D nanochannels that have the potentials for superior water permeance and precise molecular/ionic separations. To obtain target separation, researchers have developed various manipulation techniques to tune the geometric and physicochemical properties of the 2D channels that govern their separation performance. This review provided a detailed description of the properties of graphene materials and assembled 2D graphene membranes. Moreover, manipulation techniques, including reduction, crosslinking, surface modification, pore engineering, geometric engineering and responsive functionalization, to tailor their geometric and physicochemical properties for aqueous separation are analysed and compared. Additionally, fundamental mass transport mechanisms through the 2D nanoconfined channels and outlook for future studies are also discussed.