Enhanced Pervaporation Performance of Multilayer PDMS/PVDF Composite Membrane for Ethanol Concentration

摘要

Multi-layer silicone/PVDF composite membrane with an alternative silicone/PVDFon-woven-fiber/ PVDF/silicone configuration was developed by curing polydimethylsiloxane (PDMS) cast on porous PVDF substrate, which was obtained by coating PVDF solution on the double surface of non-woven fiber. The thickness of the active layer PDMS and the porous PVDF layer was ca. 10μm and 45μm respectively The multi-layer composite membrane was used for ethanol recovery by pervaporation, and exhibited enhanced separation performance compared with the common silicone/PVDF composite membranes, especially in the low ethanol concentration range. A novel phenomenon appeared that the variation of separation along with the temperature showed a turning point. The maximum separation factor was obtained at 60 ℃,and the total flux increased exponentially along with the increase of temperature. The composite membrane gave the best pervaporation performance with a separation factor of 15, permeation rate of 450g/m 2 h at a 5wt% ethanol concentration at 60 ℃.