MICROCALORIMETRIC STUDY OF ARGON, OXYGEN, NITROGEN AND CARBON-MONOXIDE ADSORPTION ON CRYSTALLINE ZIRCONIA

The adsorption of argon, oxygen, nitrogen and carbon monoxide at 77 K on crystalline zirconia and microporous zirconia gels has been studied by adsorption volumetry and isothermal microcalorimetry. The microporous structure of the zirconia gel may explain the higher enthalpy of adsorption obtained for argon. Both crystalline samples are mesoporous and in each case, the polar sites on the surface give specific interactions with dipolar (CO) or quadrupolar (N2, O2) molecules, which can be deduced from the adsorption isotherms and the corresponding differential enthalpy curves.