Separations using zeolite membranes

This overview describes some of the main features of the use of zeolite mem branes for separation applications. Four different types of separations are considered: separation of non-adsorbing compounds, of organic molecules, o f permanent gases from vapors, and of water (or polar molecules) from organ ic (or non-polar) species. Several factors, such as the limiting pore size and pore size distribution, surface diffusion, capillary condensation, shap e selectivity and molecular sieving, contribute to the separations observed . However, in most of the high selectivity separations reported in the lite rature, preferential adsorption is the dominant characteristic. In this cas e, the adsorption of one component in the mixture is stronger and this bloc ks or hinders the passage of the other components through the membrane pore s.