Cross-Linked Dialdehyde-Starch/Diethylenetriamine Sacrificial Layer for Antifouling and Sustainable Ultrafiltration Membrane Regeneration

Sacrificial layer technology has emerged as a critical strategy for addressing membrane fouling issues due to its unique “removable-regenerable” characteristics. In this study, a pH-responsive sacrificial layer was fabricated on the surface of commercial polyvinylidene fluoride (PVDF) ultrafiltration membranes through Schiff base reactions between dialdehyde starch (DAS) and diethylenetriamine (DETA), significantly enhancing membrane hydrophilicity and antifouling performance. Optimal regeneration conditions (pH = 1.0 hydrochloric acid, 50.0 °C, 2 h) were identified to achieve complete membrane performance recovery via selective acidic hydrolysis of fouled coatings. Scanning electron microscopy (SEM), attenuated total reflection Fourier transform infrared spectroscopy (ATR-FTIR), and X-ray photoelectron spectroscopy (XPS) characterizations confirmed that the cleaned membrane surface exhibited identical characteristics to pristine PVDF membranes, demonstrating complete removal of fouled coatings. Under simulated practical fouling conditions with proteins, dyes, and silicon dioxide (SiO2) microspheres, the regenerated membranes recovered 96–99% of their initial permeance. After three “coating-fouling-cleaning-recoating” cycles, the membranes maintained excellent antifouling stability (flux recovery ratio >96.2%), demonstrating exceptional regenerative capacity and stability. In summary, the DAS/DETA sacrificial layer significantly enhances the membrane’s durability, laying the foundation for future long-term stability studies and large-scale applications.