HETEROGENEITY OF PILLARED CLAYS DETERMINED BY ADSORPTION OF SF6 AT TEMPERATURES NEAR-AMBIENT

Pillared clays are studied using sulfur hexafluoride adsorption isothe rms measured at temperatures near ambient over the pressure range 1-76 0 Torr. Under these conditions the adsorption takes place predominantl y in micropores due to their enhanced adsorption potential. Data are a nalyzed using the stable numerical method for solving the adsorption i ntegral equation. The adsorption energy distributions (AEDs), which ch aracterize energetic heterogeneity of adsorbate-adsorbent interactions , are derived. It is assumed that the AED is determined by the microst ructure of the clay material and the pore width is calculated. In the discussion of the adsorption energetics the effects of pore sizes, den sity of mineral layers, and the intel action of adsorbed molecules wit h pillars are considered. The results obtained from the analysis of ad sorption data and XRD analysis are consistent. The difficulties in eva luation of pore size distribution due to the sensitivity of the assume d structural model are discussed.