Microwave-assisted hydrothermal rapid synthesis of capillary MFI-type zeolite–ceramic membranes for pervaporation application

The supported zeolite membranes prepared in this work have been synthesised under microwave heating in order to reduce synthesis time, to prevent support dissolution, and to reproducibly obtain a thin defect-free zeolite layer. The MFI-type zeolite membranes were synthesised on ceramic capillaries, with a high membrane surface area-to-volume ratio (>1000 m2 m−3), which is by far higher than that of classical tubular supports (≪500 m2 m−3). The selective layer was deposited inside, outside or on both sides of the capillaries. These hydrophobic membranes were characterized and tested in pervaporation for the separation of an EtOH/H2O: 5/95 wt.% mixture. The best results obtained at a pervaporation temperature of 45 °C, in terms of flux (1.5 kg/h m2) and selectivity (αEtOH/H2O=54αEtOH/H2O=54), were achieved with the double-sided membranes.