(713d) Fabrication of AEL Zeolite Nanosheet Membrane on Alumina Hollow Fibers for Molecular-Sieving Applications

Two-dimensional zeolites are promising materials for the fabrication of ultra-thin zeolite membranes that show high flux and separation efficiency, as demonstrated for MFI zeolite membranes. Several other zeolite frameworks have been crystallized as a multi-lamellar stack of two-dimensional nanosheets but their fabrication into membranes for separation applications still remains unexplored. In this work, two-dimensional AEL nanosheets are used to fabricate thin AEL zeolite membranes on the shell side of alumina hollow fibers to demonstrate a proof of concept for scalable non-MFI zeolite membranes that can display molecular-sieving abilities. The multi-lamellar AEL nanosheets are exfoliated through polymer melt compounding with poly(styrene). Exfoliated AEL zeolite nanosheets are then vacuum coated on the shell side of alumina hollow fibers followed by a secondary growth step to form a continuous membrane layer that is ~2 µm thick. These membranes are then activated through exposure to a high intensity UV lamp to remove the organic structure-directing agents, and their molecular-sieving ability is demonstrated through single-component vapor permeation of several organic molecules that cover a wide range of kinetic diameters. This work is the first demonstration of fabricating thin, non-MFI zeolite membranes using exfoliated zeolite nanosheets that can exhibit molecular- sieving.