Two-dimensional confined channels with high-density hydrophilic microregions for enhanced selective water transport

Two-dimensional (2D) membranes represented by graphene oxide (GO) exhibit great potential in developing high-performance separation membranes. However, insufficient interlayer chemical microenvironment and unstable laminar structure are still huge challenge to achieve high-efficiency water-selective transport. Herein, we construct high-density hydrophilic microregions in GO membrane through introducing sodium polystyrene sulfonate (PSSNa) with abundant ionized sulfonate groups to provide good hydrophilic chemical microenvironment, further facilitating fast water-selective permeation. Meanwhile, the obtained well-stacked lamina structure driven by self-assembly between PSSNa and GO nanosheets conduce to achieve superior separation of water-butanol mixture through strict size sieving effect. Consequently, the as-prepared PSSNa/GO membrane on polyethersulfone (PES) substrate exhibit excellent separation performance with flux of 5.28 kg m ⁻² h ⁻¹ and excellent separation factor of 3487 for water/butanol at 343 K, representing the state-of-the-art selective separation membranes. This strategy provides new insight to finely construct better chemical microenvironment in 2D confined channels for precise and high-efficiency aqueous molecular separation process.