Integrated polyamide thin-film nanofibrous composite membrane regulated by functionalized interlayer for efficient water/isopropanol separation

A novel polyamide thin film nanofibrous composite (TFNC) membrane was fabricated by interfacial polymerization (IP) with a modified graphene oxide interlayer on highly porous electrospun polyacrylonitrile (PAN) nanofibrous substrate for isopropanol dehydration by pervaporation. Benefiting from the utilization of ethylenediamine modified graphene oxide (eGO) lamellae, which provided thin and relatively smooth surface but also reaction sites (amine groups) for interfacial polymerization, the resultant TFNC membranes exhibited an integrated structure with a compacter and thinner polyamide (PA) selective skin layer. Significantly, the skillful regulation of interfacial polymerization by the control of deposition amount of eGO on nanofibrous substrate enabled the strong interfacial interaction and the formation of compact selective layer, determining the augment of selectivity of TFNC membranes. The optimized PA/eGO/PAN integrated TFNC membranes exhibited an excellent separation performance for dehydrating 90 wt% aqueous isopropanol solution with remarkably enhanced separation factor (1866) and high permeate flux (4150 g/m² h) at 70 °C. This result was markedly superior to those of TFC membranes prepared by IP reported so far, suggesting an efficient and facile approach to fabricate high performance pervaporation membrane with unique structures.