Pioneering silicotungstic Acid-GO nanofillers for Anti-fouling PES UF membranes toward car wash wastewater treatment

Car wash wastewater (CWW), a complex mixture of organic and inorganic pollutants, remains a pressing environmental concern due to its insufficient treatment. While ultrafiltration (UF) membranes offer a promising solution, their application is often limited due to membrane fouling. This study reports the development of polyethersulfone (PES) nanocomposite membranes reinforced with a graphene oxide-silicotungstic acid (GO-SiW) to enhance antifouling properties and treatment efficiency. GO was prepared via the modified Hummers’ technique and subsequently functionalized with SiW through solution deposition to improve hydrophilicity and dispersion stability. PES UF membranes were manufactured through the non-solvent-induced phase inversion (NIPS) method, with the GO-SiW nanomaterial incorporated into the PES matrix using a mixed matrix approach at loadings of 0.1-0.5 wt.%. Membrane characterization confirmed that GO-SiW integration improved surface roughness, porosity, and hydrophilicity, leading to enhanced membrane structure, permeability, and stability. The optimized membrane (0.4 wt.% GO-SiW, labelled M 0.4 ) exhibited a 2.2-fold increase in pure water permeance (489.9 LMH/bar), 97.4% bovine serum albumin separation, and a flux recovery ratio (FRR) of 90.6%. In long-term CWW filtration, M 0.4 showed a permeance of 115.9 LMH and FRR >86%, while achieving improved removal of total dissolved solids (TDS) (9.8-17.8%), chemical oxygen demand (COD) (54.3-56.0%), turbidity (90.0-92.3%), and total organic carbon (TOC) (53.7-56.6%) over three filtration cycles. These improvements are ascribed to the synergistic roles of GO’s hydrophilicity and SiW’s electronegativity, offering a promising strategy for developing high-performance UF membranes for sustainable wastewater treatment.