Functionalization of delaminated zeolite ITQ-6 for the adsorption of carbon dioxide

Novel functionalized adsorbents for CO(2) separation were synthesized by grafting 3-aminopropyl, 3-(methylamino)propyl, or 3-(phenylamino)propyl ligands in the delaminated zeolite ITQ-6. On the basis of the texture parameters determined from nitrogen adsorption isotherms recorded at 77 K and the results of chemical analysis, physicochemical properties of functionalized ITQ-6 were evaluated and compared with those of mesoporous SBA-15 silica functionalized with the same ligands. To examine carbon dioxide adsorption on functionalized materials, adsorption isotherms at 293 K were measured. To obtain information on the surface energetics of CO(2) adsorption on selected samples, isotherms were taken in the temperature range from 273 to 333 K and adsorption isosteres were calculated. Isosteric adsorption heats determined from the slope of adsorption isosteres proved that all of the 3-aminopropyl ligands in ITQ-6 take part in CO(2) adsorption. It was found that in the whole region of CO(2) pressures the efficiency of the amine ligand, defined as the number of adsorbed CO(2) molecules per one amine ligand, is higher for functionalized ITQ-6 than for functionalized SBA-15 silica.