Synthesis and separation properties of an α-alumina-supported high-silica MEL membrane

• Silicalite-2 (MEL) membranes on α-alumina hollow fiber supports synthesized.
• Characterization by SEM, XRD, permporometry, single gas permeation and ethanol–water pervaporation.
• Comparison to silicalite-1 membrane of similar quality, thickness and crystal orientation.
• Silicalite-2 membrane higher fluxes without loss of selectivity.

A thin high-silica MEL membrane was synthesized on a porous α-alumina hollow fiber support by a secondary growth approach. The membrane quality was evaluated by permporometry, single-gas permeation and butane isomer separation. Comparison of the pervaporation performance of MEL membranes with a MFI membrane of similar quality and thickness shows that MEL membranes offer a higher flux in ethanol pervaporation at nearly selectivity.