Enhancement of CO2 adsorption on natural zeolite, modified clinoptilolite with cations, amines and ionic liquids

The modification of clinoptilolite as a natural zeolite via a simple route was carried out for CO2 adsorption. Cation exchange with Li+, Mg2+, and Ca2+, amine modification using monoethanolamine (MEA), triethanolamine (TEA) and hexyl amine, and ionic liquid modification using [bmim]X (X = PF6⁻, NO3⁻, Br⁻, Cl⁻, and bmim = 1-Butyl-3-methylimidazolium) were performed in a different amount of the modifiers. The samples were characterized by several methods (XRD, FT-IR, BET, and SEM), and adsorbed CO2 was evaluated utilizing adsorption isotherm at a wide range of pressure. The results showed enhancement in CO2 adsorption capacity for all the samples and 4.18, 3.58, and 4.35 times increase in CO2 adsorption were obtained where clinoptilolite/Li+, clinoptilolite/2% MEA and clinoptilolite/5% [bmim]PF6 were used as adsorbent at 4 bar pressure of CO2, respectively.