Sodium‐4‐Vinylbenzenesulfonate‐Grafted Halloysite Nanotube Nanocomposite Membranes for Pharmaceutical Wastewater Treatment

A novel nanocomposite ultrafiltration membrane was developed to remove pharmaceutical pollutants from wastewater efficiently. To improve hydrophilicity and interfacial compatibility, halloysite nanotubes (HNT) were chemically grafted with sodium 4‐vinylbenzenesulfonate (SVBS) via thiol functionalization followed by free‐radical polymerization. The resulting HNT‐g‐SVBS nanofillers were incorporated into a polysulfone (PSF) matrix at various loadings (0–2 wt. %) via the phase inversion method. Comprehensive characterization using FT‐IR, TEM, FE‐SEM, AFM, and contact angle analysis confirmed the successful grafting and homogeneous dispersion of the nanofillers. The membrane containing 1 wt% HNT‐g‐SVBS exhibited optimal performance, with a 26.8% increase in pure water flux, enhanced surface hydrophilicity (as indicated by a reduction in contact angle from 69.5° to 65.6°), and 86% rejection of ibuprofen, a model pharmaceutical compound. Additionally, it demonstrated excellent antifouling performance with a flux recovery ratio of 95%. These results show that adsorption at low pH and electrostatic repulsion at high pH jointly sustain ibuprofen rejection, highlighting the need to consider multiple mechanisms when optimizing pH in membrane filtration. Long‐term filtration tests confirmed the excellent operational stability and reusability of the nanocomposite membranes (HNT‐g‐SVBS/PSF), highlighting their potential for sustainable pharmaceutical wastewater treatment.