An adhesion-printing method to coat platelike MFI seeds for the fabrication of tubular MFI zeolite membranes

Abstract

Coating crystal seeds on rough supports with curvature has been a challenge for fabricating zeolite membranes. Here, an adhesion-printing method has been developed to coat platelike MFI crystals on an Al₂O₃ tubular support to prepare MFI zeolite membranes. In this method, a macroporous Al₂O₃ tubular support is firstly enclosed with pressure-sensitive adhesive (PSA). Then a beforehand-prepared platelike MFI crystal layer is adhesion-printed on the PSA coated Al₂O₃ tubular support. An MFI seed layer on the macroporous tubular support is successfully obtained after removing the pressure-sensitive adhesive by calcination. Finally, highly (h0h)-oriented, dense and continuous silicalite-1 membranes are fabricated after a hydrothermal secondary growth in a zeolitic synthesis system, confirmed by XRD and SEM techniques. SEM observations evaluate the effect of TPAOH amount, crystallization temperature and time on the integrity and thickness of the zeolite membranes. Binary separation of butane isomers at an ambient temperature has been performed on the prepared silicalite-1 membranes, achieving a separation factor of 31.7 for an equimolar n-butane /i-butane mixture at a n-butane permeance of 6.03 × 10^− 9 mol·m^− 2·s^− 1·Pa^− 1.