"Structural Effects on the Adsorptive Properties of Molecular Sieves for Air Separation"
The structural and compositional variability of microporous zeolites and carbon molecular sieves provides a means for controlling the equilibrium and kinetic adsorption parameters over a wide range. Specific structural features can be combined to provide materials having adsorption properties best suited for a particular gas separation. After giving an introduction to adsorptive separations, examples from our past and more recent research at Air Products and Villanova on the development of adsorbents for producing oxygen, argon, and nitrogen from air will be reviewed to illustrate the remarkable importance of molecular structure and composition on selectivity, gas capacity, and uptakes rates. A multidisciplinary approach involving experimental synthesis, modeling, and extensive analytical characterization elucidated some new insights leading to improved air separation processes as well as other new applications. This review will hopefully reinforce the critical importance of using fundamental approaches to optimize adsorbent properties for a given application.