Comparative study of commercially available polymeric and microporous silica membranes for the dehydration of IPA/water mixtures by pervaporation/vapour permeation

The performance of commercially available polymeric and microporous silica membranes (both supplied by Sulzer Chemtech GmbH) was investigated with respect to the dehydration of binary mixtures of isopropyl alcohol (IPA)/water. The range of concentrations investigated (C-H2O less than or equal to 20 wt.%) was selected according to existing industrial needs. Fluxes and selectivities were monitored as dehydration proceeded, and the performance of both membranes has been compared. In addition, the effect of temperature on these parameters was investigated. Over this range, both water and IPA fluxes generally decreased with water concentration. The effect of temperature was investigated in the 70 to 105degreesC range, covering the pervaporation and vapour permeation operating conditions. Increasing the operating temperature resulted, as expected, in larger water fluxes for both polymeric and silica membranes. For the range of conditions investigated, water fluxes through the SMS membrane were found to be up to three times larger than those of the polymeric PERVAP 2510 membrane. However, IPA fluxes through the SMS membrane were also observed to be higher than those through a PERVAP 2510 membrane, resulting in a substantial decrease in separation performance.