Organic solvent nanofiltration (OSN) membranes were fabricated for the first time using poly(4-methyl-1-pentene) (PMP) via the non–solvent induced phase separation (NIPS) method for ethanol recovery from a soybean oil/ethanol mixture. Nanocomposite membranes were also prepared by incorporating graphene hydroxyl (GOH) nanosheets at varying concentrations (0.5 to 1 wt%) to evaluate their impact on membrane properties and performance. The resulting nanocomposite membranes were systematically characterized in terms of morphology, porosity, surface wettability, mechanical strength, and solvent stability. The incorporation of GOH nanosheets led to a significant increase in porosity, hydrophilicity, tensile strength, and solvent permeance (from 0.74 to 2.55 L/m²·h·bar), while maintaining high soybean oil rejection (95%). The membranes also exhibited outstanding ethanol stability with minimal swelling and near-complete gel retention after 4 weeks. These findings demonstrate a promising strategy for tailoring polymeric membranes with improved separation efficiency and sustainability. The novel PMP/GOH membrane system demonstrates strong potential for industrial solvent recovery processes, enabling energy-efficient, hexane-free oil extraction that aligns with green chemistry principles.

Keywords