(243c) Silicalite-1/amorphous Silica Mixed-Matrix Membranes By Layer-By-Layer Deposition

Recent work in the area of zeolite membrane fabrication has demonstrated the feasibility of thin, continuous, oriented zeolite films for gas and vapor separations. However, the development of simple fabrication techniques that offer facile scale-up for industrial use is a work in progress. Mixed-matrix composite membranes represent a compromise between separation performance and ease of membrane formation whereby some of the performance characteristics of the zeolite are forfeited in order to gain the processability associated with a chosen matrix material. In negotiating this compromise, balancing the matrix adsorption and diffusion characteristics with those of the zeolite is crucial. We will discuss a model that addresses this material design problem and apply it to the case of a silicalite-1 composite for organic vapor separations. Guided by insights into the optimal matrix material for this system, we will present results on the fabrication of silicalite-1/amorphous silica composites by a layer-by-layer deposition method. The films consist of alternating layers of amorphous silica and b-oriented, plate-like silicalite-1 particles with near monolayer coverage. Characterization by XRD, SEM, and vapor permeation will be presented.