Constructing low-friction mass transfer channel in laminar graphene oxide membrane for efficient molecular separation with enhanced permeability

In recent years, graphene oxide (GO) has attracted increasing interest in fabricating next-generation separation membranes. The perm-selectivity of laminar GO membrane is generally determined by their interlayer nanochannel structure. Herein, we used a new molecule called 5, 5′-diamine-2, 2′-biphenol (BIPOL-NH2) as the intercalator of laminar GO-based membrane to construct low-friction interlayer mass transfer channels. The aromatic BIPOL-NH2 molecules act as hydrophobic side walls of the mass transfer channels between adjacent GO nanosheets, reducing the interaction between water molecules and channel structure, thereby enhancing water permeability of GO membranes. This was confirmed by the further molecular dynamics simulation. Compared with pristine GO membrane, the BIPOL-GO membrane showed a water permeability increase by a factor of about 3 (up to 72.4 L m-2h−1 bar−1), which was consistent with our simulation results. Also, it represented excellent dye/salt separation performance (the selectivity of NaCl/CR is more than 117.2) and good structural stability. Overall, our work provides a novel and efficient approach to modify GO-based membranes for enhanced permeability.