Engineered PVC ultrafiltration membranes with amine-functionalized MOFs for water treatment: A comparative study on dye removal and antibacterial performance

This study developed poly(vinyl chloride)(PVC)-based ultrafiltration membranes enhanced with amino-functionalized MIL-101–NH 2 (Al/Cr) metal–organic frameworks (MOFs) using the phase inversion method. The membranes were characterized by FTIR, SEM, AFM, and contact angle measurements. The incorporation of MOFs significantly improved membrane hydrophilicity, porosity (up to ∼85%), and water uptake (nearly 80%), with the M2 (Cr) and M2 (Al) composites showing the optimal performance balance. Incorporation of MIL-101–NH 2 noticeably improved membrane performance by increasing porosity to around 85% and water uptake to nearly 80%. Among the fabricated membranes, M2 (Cr) and M2 (Al) showed the most favorable balance between pore structure and hydrophilicity. As a result, these optimized membranes demonstrated a marked enhancement in pure water flux, reaching about 534.7 L·m -2 ·h -1 for M2 (Cr) and 526.2 L·m -2 ·h -1 for M2 (Al), compared with only 276.7 L·m -2 ·h -1 for the pristine PVC membrane. Performance tests indicated that introducing hydrophilic –NH 2 groups and interconnected pores significantly improved pure water flux compared to pristine PVC. The optimized membranes exhibited effective removal of humic acid (≈70–80%), methyl orange (≈29%), and methylene blue (≈47%) due to the combined effects of size exclusion and electrostatic interactions. They also demonstrated enhanced antifouling behavior, with flux recovery ratios (FRR) of approximately 51–52% for the best-performing membranes, indicating improved cleaning efficiency relative to pristine PVC. Antibacterial evaluation using the Kirby–Bauer disk diffusion method revealed that MIL-101–NH 2 (Al) membranes displayed broader antibacterial activity against E. coli , S. aureus , and S. enteritidis , whereas MIL-101–NH 2 (Cr) showed selective activity mainly against E. coli and B. subtilis .