Development of alkali-etched ZIF-67 metal-organic framework composite incorporated PVDF UF membranes for efficient wastewater treatment

Metal-organic framework (MOF)-integrated polyvinylidene fluoride (PVDF) membranes provide a viable approach for advanced water treatment as they exhibit improved hydrophilicity and permeability, as well as antifouling characteristics. PVDF-based UF (ultrafiltration) selective membranes were modified with (zeolitic imidazolate framework) ZIF and ZIFAE (alkali-etched zeolitic imidazolate framework) MOFs in this study. Incorporating ZIFAE MOF membranes demonstrated substantially lowered contact angle, enhanced porosity, and improved flux than ZIF and PVDF membranes. Among them, the pure water flux (PWF) and bovine serum albumin (BSA) rejection of ZIFAE2 were as high as 951 ± 11 L·m⁻²·h⁻¹ and 99 ± 0.5 %, respectively. Cross-sectional and top-surface SEM images confirmed that the ZIFAE membranes showed increased pore density and uniform nanoparticle distribution, which resulted in their better hydrophilicity due to the hydroxyl (-OH) and amino (-NH) functional groups. Results of secondary effluent filtration evaluations indicated less fouling resistance and a more extended operational lifespan of the ZIFAE2 membrane. Such benefits establish ZIFAE-modified membranes as sustainable, real-world, and efficient candidates for wastewater treatment and compact alternatives to traditional tertiary treatment technologies.