Hydroxyl-enriched poly (vinyl butyral) ultrafiltration membranes via alkali treatment for enhanced antifouling and simultaneous removal of phenol and Cd(II)

While Poly (vinyl butyral) (PVB) ultrafiltration membranes offer valuable structural and mechanical advantages for water treatment applications, the absence or gradual loss of hydroxyl groups can compromise their hydrophilic nature, making them more prone to fouling over time. This work presents a straightforward approach to increase hydroxyl groups on the surface of the membrane by selectively hydrolyzing alkali-catalyzed vinyl acetate moieties in PVB while keeping the butyral backbone intact. FTIR, XPS, FE-SEM, AFM, and water contact angle measurements reveal the positive changes in surface hydrophilicity, negative surface charge, and morphological alterations of the membrane. After modification, the membranes exhibited a reasonable antifouling performance with flux recovery ratios above 95% over three filtration-cleaning cycles. Moreover, the membranes demonstrated very high phenol (99.67%) and Cd(II) ions (98.04%) rejection from wastewater under alkaline conditions, showing dual-contaminant effective separation. These synergistic improvements in antifouling and selectivity are attributed to enhanced electrostatic interactions and increased hydrophilicity. This study introduces a straightforward approach for the potential non-destructive modification of PVB-based membranes. While further validation is needed to assess scalability, the work demonstrates the applicability of the modified membranes for wastewater treatment, particularly for the removal of organic contaminants and heavy metals. • Alkaline surface-hydrolysis yields hydroxyl-rich PVB UF membranes. • Increased hydrophilicity and negative charge improve antifouling. • Simultaneous removal of phenol (99.67%) and Cd(II) (98.04) • Flux-recovery ratio ≥ 95% over three foul/clean cycles (best ∼98%) • Simple, scalable, low-cost route compatible with existing membrane lines