Upcycling Expandable Polystyrene Waste Into Polymeric Membranes as Promising Micro/Ultrafiltration Membranes for Humic Acid and Bovine Serum Albumin Removal from Water

Expanded polystyrene (EPS) waste was recycled into polymeric micro/ultrafiltration membranes for water purification applications. EPS‐based membranes containing 19.2, 20, and 24 wt.% polymer were fabricated via the non‐solvent induced phase separation (NIPS) method, while polyethylene glycol (PEG) was incorporated at 3.84 and 8 wt.% to improve membrane characteristics. The membranes were characterized using Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), contact angle measurements, and mechanical testing. FTIR confirmed the characteristic polystyrene functional groups, while SEM revealed that membrane M2 (24 wt.% PS and 3.84 wt.% PEG) possessed the most favorable pore structure. M2 exhibited improved mechanical properties with elongation and tensile stress values of 72.6% and 69.2 MPa, respectively. The membrane achieved a pure water flux of 179 LMH and demonstrated average rejection efficiencies of 97% for humic acid and 92% for bovine serum albumin. In addition, the fabricated M2 has the best antifouling behavior with flux recovery ratio more than 90%. The fabricated M2 membrane exhibited the best overall filtration performance for 6 h and the highest cleaning efficiency for eight cycles. This study demonstrates that upcycling EPS waste into MF/UF membranes represents a sustainable way for water purification.