High-performance polyamide/ceramic hollow fiber TFC membranes with TiO2 interlayer for pervaporation dehydration of isopropanol solution

Abstract

To improve the pervaporation (PV) performance of isopropanol (IPA) dehydration, polyamide (PA) thin-film composite (TFC) membranes were fabricated by interfacial polymerization (IP) of 1,3-diaminopropane (DAPE) and trimesoyl chloride (TMC) on the surface of TiO2 modified ceramic hollow fiber (CHF) substrate. The TiO2 interlayer prepared by the sol-gel method completely cover the rough and macroporous surface of the α-Al2O3 hollow fiber, providing relatively smooth and intact surface but also abundant electrostatic sites (hydroxyl) for better IP. The PA layer prepared on the TiO2 interlayer is thinner, defect-free and exhibited higher smoothness and cross-linking degree than that on the original CHF support. The effects of monomer concentration, immersion time in aqueous phase and contact time of TMC solution were also investigated. The TFC membrane prepared under optimum conditions exhibited the outstanding PV separation index (PSI) value of 7.83 × 107 with separation factor above 12,000 and the permeate flux nearly 6.44 kg/m2 h for PV dehydration of 90 wt% IPA at 60 °C. After 100 h of long-term operation, the PV membrane maintains the high separation performance. This TFC membrane prepared by an effective and simple method provides an alternative for designing high-performance PV membrane in organics dehydration.