Modeling, film formation, and material synthesis for performance optimization of mixed matrix membranes.

Abstract

Mixed matrix membranes offer the hope of improving the performance of a separating membrane by dispersing a second phase within it. By combining the processability of a continuous phase (the matrix) with the separation characteristics of a dispersed phase (the flake), mixed matrix membranes aim to provide a step-change improvement in membrane performance without dramatically increasing the cost of membrane technology. In this dissertation, a numerical model for the performance of mixed matrix membranes is presented that accounts for effects such as competitive adsorption and concentration-dependent diffusivities. It is shown that these effects are vital for the modeling of a membrane containing zeolite flakes. This insight is then used to formulate a semi-empirical model for mixed matrix membrane performance that does not require extensive numerical calculations. Through a series of case studies on relevant gas and vapor separations, these models are applied to material and process design for mixed matrix membranes. Finally, experimental aspects of mixed matrix membrane formation are presented, including the synthesis of layered aluminophosphate molecular sieves and the fabrication of mesoporous silica/silicalite-1 zeolite films.