ABSTRACT
Zeolite-based separations involve pressure swing or temperature swing adsorption. These are unsteady-state processes which rely on cycles of preferential adsorption (of one component over the other) and subsequent desorption. Replacement of a swing adsorption process with a steady-state process is arguably advantageous for several reasons, including lower operating costs and reduced energy consumption. Over the last decade, much attention has been focused on the development of continuous zeolite-based separations processes. For such purposes, the natural configuration of the zeolite material is in the form of a thin film or membrane supported on, or deposited in, a porous substrate. A wellfabricated zeolite membrane would be expected to behave as a continuous separation device, with reasonably high selectivity and flux. Many separations that are currently carried out using distillation, crystallization, and other conventional processes can be carried out with a much less energy-intensive zeolite membrane-based separation process. The widely exploited catalytic properties of zeolitic materials also imply the possibility of catalytic membrane reactor processes, combining selective catalysis with selective separations.
