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. [Display omitted] •Modification of the natural zeolite using the simple and economical route.•Utilizing of cations, amines and ionic liquids for increasing of CO2 adsorption.•Enhancement of CO2 adsorption in the modified natural zeolite (clinoptilolite).•Increasing the CO2 adsorption capacity for some of the samples more than 4 times.