Enhanced Water Permeability and Reduced Fouling with Silver-Functionalized MWCNT-COOH Hollow Fiber Membranes

Membrane fouling, particularly organic and biofouling, remains a persistent challenge that limits the long-term performance of ultrafiltration membranes. These are significant problems, particularly for municipal wastewater, where organic and biofouling, together with fouling, arise from suspended inorganic and suspended matters. In this study, silver-functionalized carboxylated multiwalled carbon nanotube (Ag/MWCNTs-COOH) nanocomposites were synthesized, characterized, and successfully incorporated into polysulfone (Psf) hollow fiber membranes (HFMs). The incorporation of Ag/MWCNTs-COOH significantly modified the physicochemical properties of the HFMs, resulting in markedly enhanced permeability and fouling resistance. The PAM-50 HFMs exhibited a substantial increase in pure water permeability (PWP), reaching 154.68 ± 3.15 L·m –2 ·h –1 ·bar –1 compared to 79.4 ± 2.11 L·m –2 ·h –1 ·bar –1 for pristine HFMs. They also demonstrated excellent antifouling performance, achieving flux recovery ratios (FRR) of ∼96% bovine serum albumin (BSA) and ∼93% synthetic municipal wastewater (SMWW). Furthermore, protein adsorption on PAM-50 HFMs was markedly lower (0.07 mg·cm –2 ) than that on the unmodified membranes (1.64 ± 0.12 mg·cm –2 ). Importantly, the modified membranes also exhibited superior antibiofouling activity, maintaining ∼32% flux recovery after 24 h of exposure to Escherichia coli, whereas the unmodified membranes showed negligible recovery (∼0.97%). Complementary 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay, crystal violet (CV) staining, SEM, and confocal microscopy confirmed reduced bacterial attachment and biofilm formation. Overall, the incorporation of Ag/MWCNTs-COOH nanocomposites endows Psf HFMs with synergistic antifouling and antibiofouling properties, highlighting their promise for advanced wastewater treatment applications.