7. Zeolites and Other Adsorbents

Zeolites are crystalline nanoporous aluminosilicates, which have been used as selective and efficient catalysts and adsorbents in several industrial applications. Their use as adsorbents since their discovery is briefly reviewed. The main characteristics that render this group of materials and other closely related suitable for adsorptive separation applications are presented. A number of adsorption separation and/or purification processes which either use zeolites or for which zeolites have been proposed and studied as the key adsorbent are reviewed, as well. Amongst them, we find industrial applications, such as drying of gases and liquids, air separation and linear from branched hydrocarbon separations. Other separation processes still under development, such as carbon dioxide removal from post-combustion gases, methane purification, methane storage or olefin/paraffin separation, have been included in this chapter. Despite being a mature research area in adsorption, zeolite-based separation processes are still blooming because of the advent of new zeolite structures and/or compositional variants that could allow for other challenging separations in the near future. Amongst them, pure silica zeolites are found to be outstanding adsorbents since they combine high adsorption capacities and excellent regenerabilities in swing adsorption processes.