Pervaporation is a membrane process in which a liquid is maintained at atmospheric pressure on the feed or upstream side of the membrane and where the permeate is removed as a vapor because of a low vapor pressure existing on the permeate or downstream side.
Dense homogeneous polymer membrane can separate various gaseous or liquid mixtures very effectively. However, normal thickness lead to very low permeation rate. So in this study, PDMS/ceramic composite membrane was used in pervaporation process in order to enhance the flux with maintaining proper selectivity.
Pervaporation characteristics can be influenced by several process variables. Selectivities of IPA decreased and fluxes increased with concentration of IPA in feed mixtures. In the pervaporation using homogeneous PDMS membrane without ceramic support, selectivities of IPA were inversely proportional to operating temperature. But, in removal of IPA from aqueous IPA solution using PDMS/ceramic composite membrane, selectivities of IPA increased with operating temperature in the range from 0 to 20wt.% of IPA in feed mixtures. This phenomenon could be explained in terms of coupling effects between permeant and composite membrane and between permeants. Among these effects, capillary condensation could be importantly considered due to hydrophilicity of ceramic support. These coupling effects were observed by measuring permeation ratios of each component.
