New nano-structured sorbent materials for gas separation, purification and storage.

摘要

Nanoporous sorbent materials have a large portion of their surface area in the nanopores, which is suited for adsorption of various molecules. This property provides scope for the synthesis and tailoring of new nano-structured materials towards specific gas separation, purification and storage needs. This dissertation discusses the synthesis, characterization and evaluation of several nano-structured sorbent materials for use in specific gas separation, purification and storage applications. These materials include carbon molecular sieves, natural/modified clinoptilolites, partially cerium exchanged zeolites, silver salts dispersed on silica gel, pi-complexation sorbents and activated carbon/carbon fiber. Two types of carbon molecular sieves were examined for CH4/CO2 separation and temperature was found to play a key role in kinetic PSA separations. Clinoptilolites were tailored for methane upgrading. Purified, mixed Mg/Na and Na/Ce clinoptilolites were shown to be competent with a commercial CH4/N2 separation process. Mixed Na-Ce-X zeolites were found to exhibit crossover of N2 and O2 isotherms leading to oxygen selectivity at very low pressures. Stable oxygen selective sorbents were developed with silver and cerium salts. AgBr dispersed on SiO2 showed good oxygen selectivity for N 2 production by PSA. pi-complexation sorbents were found to be severely deactivated by H2 exposure and the rejuvenation of pi-complexation capability was obtained by mild oxidation and the optimum conditions were identified. Pt dispersed on activated carbon fiber was found to influence H2 storage by spillover.