Fabrication and Characterization of a Nanofiber‐Modified Polysulfone Membrane With Polyvinyl Alcohol/Chitosan Interlayer to Enhance Flow Rate and Selectivity

ABSTRACTThin‐film composite (TFC) membranes comprising polysulfone substrates and polyamide active layers exhibit limited water permeability due to intrinsic hydrophobicity. In this study, membrane hydrophilization was developed by applying an electrospun polyvinyl alcohol/chitosan nanofiber interlayer between the support and active layer. Crosslinking the nanofibers with glutaraldehyde enhanced their water stability. Spectroscopic, electron microscopic, and water contact angle measurements confirmed successful integration and structural stability. The average fiber diameter was 236 ± 13 nm and increased to 991 ± 21 nm after forming the polyamide layer via interfacial polymerization, confirming successful layer formation. The contact angle was reduced from 62.4° to 32.5°, indicating a 49.5% improvement in surface hydrophilicity, leading to a 42% increase in pure water flux compared to unmodified polysulfone membranes. After interfacial polymerization, a moderate flux decline of 21% was observed due to the formation of the dense polyamide barrier layer; however, the modified membranes exhibited superior permeability compared to conventional polysulfone TFC membranes. The salt rejection efficiency was maintained at 88%, with minimal compromise of about 10% in selectivity. These findings indicate that using nanofiber‐assisted interlayer modification is an effective and scalable method for producing high‐performance TFC membranes, suitable for advanced desalination and wastewater treatment applications.