Aminopropyltriethoxysilane‐enhanced activated carbon with polyethersulfone/ cellulose acetate mixed matrix nanofiltration membranes for water purification

Abstract

Nanocomposite mixed matrix membranes (MMMs) have emerged as a promising solution for industrial wastewater treatment and desalination, owing to their tunable structures, scalable fabrication and incorporation of high‐performance materials. In this study, modified activated carbon (MAC) particles functionalized with aminopropyltriethoxysilane as a crosslinker were incorporated into a polyethersulfone/cellulose acetate blend to fabricate MMMs via the phase inversion method. The MAC content range was 0–2 wt%, with polyvinylpyrrolidone (7.5 wt%) as the optimized pore‐forming agent. SEM revealed asymmetric dense selective layer and porous finger‐like sublayer structures, indicating uniform particle dispersion. The membrane porosity increased with MAC loading, reaching 80% at 1.0 wt%, and the water contact angle significantly decreased to 30°, indicating improved wettability compared to the pristine membrane (57°). TGA confirmed improved thermal stability with nanofiller addition over 400 °C. The optimized membrane (1.0 wt% MAC) exhibited a pure water flux of 90 ± 0.09 L m ⁻²  h ⁻¹ (relative standard deviation (RSD) = 0.1%, n  = 3) and salt rejections of 34% ± 0.17% (RSD = 0.5%, n  = 3) for NaCl, 81% ± 0.05% (RSD = 0.06%, n  = 3) for MgSO ₄ and 90% ± 0.08% (RSD = 0.09%, n  = 3) for Na ₂ SO ₄ , outperforming the pristine membrane. Additionally, the flux recovery ratio value was enhanced from 64% ± 1.63% (RSD = 2.55%, n  = 3) (pristine membrane) to 81% ± 0.82% (RSD = 1%, n  = 3) for the optimized membrane (M4AC2). These findings demonstrate an effective strategy for developing high‐performance, sustainable nanofiltration membranes for advanced water purification applications. © 2026 Society of Chemical Industry.