Hydrogen (H2) adsorption on natural and cation-exchanged clinoptilolite, mordenite and chabazite

Abstract

In this study, clinoptilolite (CLN), mordenite (MOR) and chabazite (CHA) from Turkey and those of H+-, Na+-, K+-, Li+-, Ca2+- and Mg2+- exchanged forms were investigated for hydrogen storage at 77 K using volumetric apparatus up to 100 kPa. Cation exchange procedures were carried out using 1.0 M HCI, KNO3, LiNO3, NaNO3, Mg(NO3)2 and Ca(NO3)2 solutions at 90 °C for 5 h. Structural characteristics of these zeolite samples were investigated using XRD, XRF and N2 adsorption techniques. Experimental results showed that the chabazite samples (0.474–1.082 wt %) had a higher hydrogen adsorption capacity than mordenite (0.224–0.337 wt %) and clinoptilolite (0.065–0.555 wt %) samples. The variations in the level of hydrogen adsorption of original and cation exchanged natural zeolites were discussed in terms of the induced differences in their structural properties.