Silicalite-1 zeolite membranes on unmodified and modified surfaces of ceramic supports: A comparative study

Abstract

Silicalite-1 zeolite membranes were prepared hydrothermally on the porous ceramic supports, both unmodified and modified with 3-aminopropyl triethoxysilane (APTES) as a coupling agent following ex situ (secondary) crystal growth process. The microstructure of the membranes was examined by scanning electron microscopy (SEM). The permeation study with a single gas, nitrogen (N₂) was performed through the membranes. For the surface modified support, a more surface coverage of the seed crystals on the porous support was observed resulting in a relatively higher dense packing of the crystals during secondary crystal growth process compared to that obtained from the unmodified support. The membrane developed on surface modified support rendered lower permeance value i.e. 9 × 10⁻⁷ mol m⁻² s⁻¹ Pa⁻¹ of N₂ compared to that formed on the unmodified support which gave permeance value of 20 × 10⁻⁷ mol m⁻² s⁻¹ Pa⁻¹ of N₂.