Zeolite membranes supported on porous stainless steel were prepared by hydrothermal method under static condition and characterized through XRD, SEM, nitrogen adsorption and mercury porosimeter method. The prepared membrane has a MFI structure (silicalite) which is hydrophobic and ethanol permselective. The membrane consists of the aggregates of elongated prismatic crystals whose sizes were in the range of 2 to 5μm The average thickness of membrane was ca. 300μm.
The influence of the feed temperature, feed concentration and downstream pressure on the pervaporation performance of silicalite membrane was studied. The pervaporation rate increased linearly with temperature due to the higher vapor pressure of the components of the feed, while the separation factor α(EtOH/$H_2$O) slightly decreased. Pervaporation separation index(PSI) slightly increased with the temperature. Pervaporation rate as well as separation factor decreased with ethanol concentration in the feed from 5 to 80 wt%. The pervaporation rate decreased with downstream pressure, while the PSI was found to be maximum at 8 mbar.
