Effect of calcination temperature on the PV dehydration performance of alcohol aqueous solutions through BTESE-derived silica membranes

Organic-inorganic hybrid membranes from 1,2-bis (triethoxysilyl)ethane (BTESE) were prepared by sol-gel processing, and we examined the effects of firing temperatures ranging from 100 to 300 °C on membrane separation performance. The contact angle, thermogravimetric (TG) and infrared (IR) spectrum showed that the structure of the membrane changed with top-layer firing temperatures. BTESE-100, prepared by firing at 100 °C, showed an He permeance of 2.2×10−7 mol/(m2 s Pa) with a He/SF6 separation factor of about 140, while BTESE-300, prepared by firing at 300 °C, showed a He/SF6 of about 3000 with an He permeance of 1.5×10−6 mol/(m2 s Pa). In pervaporation (PV) dehydration of a 90 wt% isopropanol (IPA) aqueous solution at 75 °C, BTESE-100 and BTESE-300 showed water fluxes of 2.51 and 3.40 kg/(m2 h) with separation factors of 130 and 4370, respectively. Moreover, BTESE-100 showed a stable PV flux and separation factor for more than 10 h, confirming the successful preparation of BTESE membranes at low firing temperatures.