Effects of Slow Mass Transfer When Using Microporous Adsorbents in Gas—Solid Chromatography

Abstract
The elution behaviors of CH4, C2H6, n-C3H8, iso-C4H10, Ar. O2, N2, and SF6 were studied in A-type zeolites containing K+, Na+, Li+, Sr2+, Ca2+, and Mg2+ and on a 10X zeolite. Temperature- and flow-dependent tailing of peaks and changes in retention volume with flow rate were found for those adsorbates able only to partially penetrate the pores. When diffusivities were large enough to allow total access to the pores, molecular size and the degree of adsorption for the adsorbate had significant effects — on HETP values.