Mg(Al)O mixed metal oxides as nanofiller for the preparation of sustainable antifouling polyethersulfone membranes

• Sustainable ultrafiltration mixed matrix membranes with Mg(Al)O using Polarclean as an alternative green solvent. • Mg(Al)O nanofiller NPs (0–1 wt.%) enhanced permeability, dye removal, and fouling resistance. • 1 wt.% Mg(Al)O gave the best performance: 107.2 L m⁻² h⁻¹ water flux and higher dye rejection. • Improved antifouling properties: higher flux recovery ratio of 76.8%, and lower irreversible fouling ratio of 23.2%. This study aims to develop a high-performance and sustainable ultrafiltration (UF) membrane by incorporating Mg(Al)O mixed metal oxide nanoparticles (NPs) into a polyethersulfone (PES) matrix. The membranes were fabricated using the non-solvent-induced phase separation (NIPS) method, with PolarClean as a green solvent and water as a coagulation bath, and applied for dye removal. The effect of Mg(Al)O content (0 – 1 wt.%) on the membrane properties was investigated, demonstrating that the incorporation of Mg(Al)O enhances permeability, dye rejection, and antifouling performance compared to the pristine PES membrane. The membrane containing 1 wt.% of Mg(Al)O exhibited the best performance in terms of improved hydrophilicity, enhanced pure water flux with a value of 107.2 L m −2 h −1 at 2 bar, and superior dye rejection for a 50 mg L −1 Acid Red 4 aqueous solution. Additionally, the Mg(Al)O/PES membrane showed excellent antifouling properties, achieving a flux recovery ratio ( FRR ) of 76.8% and reduced irreversible fouling ratio ( R ir = 23.2%). These findings highlight the potential of Mg(Al)O NPs as effective nanofillers for UF membranes designed for efficient dye rejection while promoting the use of easy and environmentally friendly fabrication methods.