Engineered polyethersulfone UF membranes with sulfonated polyaniline-graphene oxide: Optimizing permeability and antifouling

This study investigates the enhancement of ultrafiltration membranes by incorporating polyaniline-graphene oxide (PANI-GO) and sulfonated polyaniline-graphene oxide (SPANI-GO) nanocomposites into sulfonated pol- yethersulfone (SPES) and polyethersulfone (PES) matrices employing the non-solvent induced phase separation (NIPS) approach. A thorough characterization of the resulting membranes was conducted, including attenuated total reflectance-Fourier transform infrared spectroscopy (ATR-FTIR), X-ray diffraction (XRD) analysis, and thermogravimetric analysis (TGA), to evaluate their structural, morphological, and thermal properties. The study also examined mechanical properties, porosity, water uptake, hydrophilicity, permeability, and antifouling performance, focusing on the role of PANI-GO and SPANI-GO nanofillers. The addition of sulfonated polyaniline nanofillers significantly improved membrane hydrophilicity and surface roughness, increasing water flux and enhancing antifouling performance. The sulfonation of the matrix further amplified hydrophilicity, resulting in higher permeability. Notably, the hybrid membrane containing PES-SPANI-GO demonstrated a pure water flux of 275 L/m2h at a feed pressure of 1 bar, nearly double that of the unmodified membrane (128 L/m2h). The modified membranes exhibited outstanding resistance to fouling by natural organic matter (NOM), achieving over 99 % contaminant removal without compromising rejection efficiency. This improvement is due to the synergistic effects of boosted hydrophilicity and optimized surface morphology, which promote superior permeability and antifouling capabilities. Integrating PANI-GO and SPANI-GO into SPES and PES frameworks results in robust, highly hydrophilic membranes with excellent antifouling features, making them strong can- didates for a wide range of filtration implementations.