Application of inverse gas chromatography in the study of the adsorption properties of natural, dealuminated and lead exchanged zeolitic tuffs

摘要

Two zeolitic tuffs, Mexican and Hungarian, containing clinoptilolite and mordenite, were characterized by X-Ray diffraction, X-Ray fluorescence spectroscopy, infrared spectroscopy and nitrogen adsorption measurements at 77 K as natural, dealuminated and lead exchanged samples. Adsorption isotherms in the temperature interval 322 K < T < 400 K and the thermodynamic parameters -(&UDelta;H-ads) over bar and (&UDelta;S-ads) over bar /R, Henry's K-H and Freundlich's k(F) adsorption constants were calculated with the aid of inverse gas chromatography (IGC) by the single peak method for the alkanes: C-5 to C-8 in the low pressure region (p < 5 mm Hg). Adsorption isosters and the variation of the isosteric heat of adsorption q(isost) with surface coverage was further calculated on the basis of the experimental adsorption isotherms treated as analytical functions for individual vapors. [References: 14]