Graphene oxide framework membranes intercalated by poly(sodium 4-styrenesulfonate) for efficient desalination

GO membranes with well-defined sub-nanometer channels are optimal for desalination and wastewater purification. However, the inherent instability of the interlayer structure and the severe trade-off between selectivity and permeability pose a significant challenge for GO membranes to be effectively applied to nanofiltration. Herein, we synthesized a series of PSSNa-GO-EDA/Al 2 O 3 membranes by embedding poly(sodium 4-styrenesulfonate) (PSSNa) into ethylenediamine-crosslinked GO interlayers. The resultant membranes exhibited greater interlayer structures, in which new hydrophilic confined nanostructures were constructed. Effective nanofiltration performance was achieved through electrostatic-induced ion-confined partitioning. The PSSNa-GO-EDA-1/Al 2 O 3 (PGE-1) membrane showed high rejection rates of 86.0% for Na 2 SO 4 and 53.8% for NaCl while maintaining competitive pure water permeance of 10.85 LMH/bar, which is 12.1 times higher than that of the pristine GO membrane. More importantly, after immersion in pure water for 680 hours, this membrane retained commendable separation performance. Overall, our work provides an effective strategy to finely fabricate confined nanostructures in lamellar GO-based nanofiltration membranes featuring excellent separation performance.