High-performance polyamide composite membranes via double-interfacial polymerizations on a nanofibrous substrate for pervaporation dehydration

• Published in: Separation and purification technology Vol. 257; p. 117927
• Main Authors: Li, Peiyun, Shen, Ke, Zhang, Tonghui, Ding, Siping, Wang, Xuefen
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 15.02.2021
• Subjects: Double-interfacial polymerization; Pervaporation dehydration; Thin-film nanofibrous composite membrane; Thin-film nanofibrous composite membrane; Pervaporation dehydration; Double-interfacial polymerization
• ISSN: 1383-5866; 1873-3794
• DOI: 10.1016/j.seppur.2020.117927

•A novel double-IP route was developed to prepare excellent pervaporation membranes.•A-PA layer could regulate the structure and morphology of S-PA layer.•A compact and ultrathin Bi-PA layer was achieved for efficient pervaporation dehydration. A novel double-interfacial polymerizations (double-IP) strategy was demonstrated for the maneuverable fabrication of high-performance polyamide (PA) composite membranes based on nanofibrous substrates for efficient isopropanol dehydration by pervaporation. Firstly, an ultra-thin auxiliary polyamide layer (A-PA) was synthesized on a highly porous polyacrylonitrile (PAN) nanofibrous substrate by using low concentration ethylenediamine (EDA) and trimesoyl chloride (TMC) solution, which decreased the reaction rate and prolonged polymerization time to achieve a smooth, relatively loose but intact A-PA layer. Secondly, a more compact PA selective layer (S-PA) was fabricated with relatively high concentration EDA and TMC solution on A-PA surface. Benefiting from the A-PA layer, the amount and diffusion rate of adsorbed EDA solution through the layer to contact TMC solution were effectively controlled in second IP process. S-PA layers tended to be more uniform, and there was no marked void or detachment observed between two PA layers. Significantly, the pervaporation performance of as-prepared membranes were tuned by changing the structure of S-PA layers with the assistant of different A-PA layers. The optimized two-tier polyamide (Bi-PA) thin-film nanofibrous composite (TFNC) pervaporation membranes exhibited high permeate flux (6075 g/(m2 h)) and enhanced separation factor (1314) for dehydrating 90 wt% aqueous isopropanol solution at 70 °C. This work may suggest an efficient and facile approach to fabricate high performance pervaporation membranes.