Construction of antifouling and renewable nanofiltration membranes through surface self-assembly for dye/salt separation

Polyamide (PA)-based nanofiltration (NF) membranes often suffer from low water permeability and limited salt/dye separation efficiency due to dense selective layers. This work precisely regulated pore size by grafting azobenzene (Azo) and incorporating β-CD, which captures dyes via molecular recognition, enhancing dye/salt separation. The numerous hydrophilic hydroxyl groups present on the exterior of β-CD cavities improve membrane surface hydrophilicity, thereby optimizing the functionality of membrane surface. The contaminants adhering to membrane surface can be simply eliminated utilizing UV irradiation to disrupt the interactions between β-CD and Azo. More importantly, the membrane could then be reconstructed by re-immersing it in a fresh β-CD solution. The optimized membrane demonstrated a notable flux reaching 32.4 L/m 2 ·h·bar, along with an impressive CR/Na 2 SO 4 selectivity ratio of 220.