Energy-efficient and environmentally benign organic solvent nanofiltration (OSN)-based thin-film composite (TFC) membranes were fabricated on partially hydrolyzed polyacrylonitrile (HPAN) membranes via in situ oxidative polymerization of polyaniline (PANI). A three-layered PANI coating was applied using the layer-by-layer (LbyL) deposition technique to optimize efficiency. The separation efficiency of these membranes was evaluated for the recovery of n-hexane from vegetable-oil-based micelles using dead-end stirred cells. The membranes' microstructures, surface morphology, structural properties, thermal stability, tensile strength, and hydrophilicity were characterized using SEM, FTIR, TGA, CA, and UTM. Findings indicate that HPAN membranes with a single PANI coating exhibited less than 1% or negative rejection due to inadequate conversion from ultrafiltration (UF) to nanofiltration (NF). Membranes with a double PANI coating demonstrated NF membrane properties with reduced rejection rates. Triple PANI-coated membranes exhibited superior rejection of flaxseed, corn, soybean, sesame, and sunflower oils. It is concluded that the LbyL method for PANI deposition may be effectively utilized to enhance the performance efficiency of OSN-TFC membranes in the oleochemical industry, thereby minimizing solvent recovery waste.
Ali et al. (Sun,) studied this question.