A highly permeable Al-based MOF-sulfonated polyaniline/polyethersulfone composite UF membrane with prominent antifouling properties

This study focuses on the development and evaluation of novel ultrafiltration (UF) membranes by incorporating PANI-Al-MOF (polyaniline metal–organic frameworks) and SPANI-Al-MOF (sulfonated polyaniline metal- –organic frameworks) into a polyethersulfone (PES) matrix. The research aims to improve membrane properties and filtration performance, highlighting the novelty of using MOF-modified PES membranes for enhanced water treatment applications. The membranes were fabricated using the phase inversion method with varying MOF concentrations (1 %, 3 %, and 5 %). Comprehensive characterization techniques such as FTIR, mechanical testing, AFM, and SEM were employed to evaluate their properties.The modified membranes showed a remarkable increase in hydrophilicity, as evidenced by a reduction in water contact angle from 85.8◦ for neat PES to 65.1◦ for MPSPAl 5 %, which contributed to an increase in surface free energy. The pure water flux also improved significantly, increasing by 60 % from 153 L/m2⋅h (PES) to 368 L/m2⋅h for MPSPAl 5 %. Additionally, the incorporation of MOFs resulted in enhanced porosity and reduced surface roughness, with RMS roughness values decreasing from 7.23 nm (PES) to 2.87 nm for MPSPAl 1 %. The modified membranes exhibited excellent antifouling performance, with a flux recovery ratio (FRR) of up to 86.6 % for MPSPAl 5 % and a 63 % increase in reversible fouling resistance (Rr). Furthermore, the rejection efficiency for humic acid (HA) improved from 92 % (PES) to 97 % for MPSPAl 5 %. These findings demonstrate that the integration of PANI-Al-MOF and SPANI-Al- MOF into the PES backbone significantly enhances the membrane’s filtration efficiency, hydrophilicity, and fouling resistance, making these membranes promising candidates for advanced water treatment applications.