Chapter 1.1 Computational studies on the design of synthetic sorbents for selective adsorption of molecules

Abstract

Publisher Summary Selective adsorption of molecules is of paramount importance in the gas phase separation technology. Conventionally zeolite catalysts are widely used as molecular sieves and shape selective catalysts. However, the extra framework cations, particularly the protons in zeolites are source of unwanted reactions in selective adsorption and separation of molecules. Recently, crystalline aluminophosphates having microporous structures are reported. Aluminophosphates (AlPOs) are having neutral framework with regularly alternating [AlO4]- and [PO4]+ tetrahedra. The AlPOs do not have extra framework cations and they can be synthesized with novel pore shapes and sizes. Carbon molecular sieves have also been known to be inert and applicable to gas separation applications for reasonably long time. Recent discovery of molecular carbon structures such as carbon nanotubes has provided impetus to search for new selective adsorption applications of such materials. The selective adsorption of molecules over ceramics and extraction with supercritical fluids is also an emerging technology. This chapter presents the results of computational studies on the above mentioned novel inorganic systems namely AlPOs, carbon nanotubes and supercritical fluid extraction from the adsorbed phase over ceramics. Multi-technique computational methods such as Computer Graphics (CG), molecular mechanics (MM), quantum chemistry (QC) and molecular dynamics (MD) are applied. The attempts made to design synthetic sorbents at molecular level are reviewed.