Core–shell zeolite composite with enhanced selectivity for the separation of branched paraffin isomers

Abstract

A zeolite beta–silicalite-1 composite was prepared by growing polycrystalline silicalite-1 shells on single micron-sized zeolite beta crystals. The obtained core–shell material was employed for the separation of hexane isomers. Gravimetric uptake measurements revealed that the silicalite-1 shell acted as a membrane that controlled the transport to zeolite beta core. The positive impact of the silicalite-1 membrane on the separation of mono- and di-branched hexane isomers was confirmed by breakthrough experiments. The core–shell composite material allowed more selective separation of mono- and di-branched isomers than either of its components alone and had a significantly higher adsorption capacity than silicalite-1.