Thin-film composite tri-bore hollow fiber (TFC TbHF) membranes for isopropanol dehydration by pervaporation

Abstract

For the first time, this paper reports the fabrication of novel thin-film composite tri-bore hollow fiber (TFC TbHF) membranes for pervaporation dehydration of isopropanol (IPA). The interfacial polymerization conditions were first optimized using the conventional single-bore hollow fiber (SbHF) substrate. Then, the effects of spinning parameters such as bore fluid composition, bore fluid flow rate, air gap and dope flow rate on TFC TbHF membranes׳ geometry, morphology and pervaporation performance were systematically investigated. It was found that the bore fluid composition is the most critical factor. Moreover, fine TFC TbHF membranes with an outer diameter of approximately 1mm exhibit better separation performance for IPA dehydration than thick TFC TbHF membranes with an outer diameter of approximately 2mm. The optimal TFC TbHF membrane shows a flux of 2.65kgm−2h−1 with a separation factor (water/IPA) of 261 for the dehydration of an IPA/water (85/15wt%) mixture at 50°C. Most importantly, the newly designed TFC TbHF membrane not only shows enhanced separation performance and mechanical strengths as compared with the conventional TFC SbHF spun from the identical spinning conditions, but also exhibits satisfying long-term stability, suggesting its a great potential for pervaporation applications.