Hollow fiber composite membranes of poly(paraterphenyl-3-bromo-1,1,1-trifluoroacetone) and PVA/glycine for ethanol dehydration

Abstract

Thin film composite hollow fiber membranes (TFC-HFMs) usually have permeate flux of less than 2 kg m−2 h−1 for pervaporation (PV) dehydration of ethanol, as well as complicated and pragmatic preparation process, limiting their application in the PV. In this study, the TFC-HFMs with excellent PV performance are fabricated on newly-developed poly(paraterphenyl-3-bromo-1,1,1-trifluoroacetone) (PTB) hollow fiber supports. The PTB hollow fiber supports exhibit low mass transfer resistance as a result of high pure water permeance of 1.6 × 103 L m−2 h−1 bar−1, high porosity of 63.8% and mean pore size of 2.53 μm. Furthermore, self-assembly sandwich structure dense-selective layers are formed on the lumen side of PTB hollow fiber supports via heterostructured evolution that derives from a mixture of polyvinyl alcohol (PVA) and glycine (Gly). The resulting TFC-HFMs display the excellent separation performance. Especially, the TFC4.1-HFMs show a high permeate flux of 3.49 kg m−2 h−1, 91.1 wt% water in the permeate and excellent stability for dehydrating 85 wt% ethanol aqueous solution at 50 °C. The newly developed TFC-HFMs should have a wide application in the PV dehydration of ethanol due to simple preparation progress and efficient separation.