Surface Area Measurements with Linear Adsorbates: An Experimental Comparison of Different Theoretical Approaches

D. S. RAWAT; A. D. MIGONE; J. L. RICCARDO; A. J. RAMIREZ-PASTOR; F. ROMÁ

LANGMUIR

AMER CHEMICAL SOC

Año: 2009 vol. 25 p. 9227 - 9231

0743-7463

The specific area of a substrate was determined from the results of adsorption isotherms performed with a sequence offour alkanes, from methane to butane, using three different approaches. The data were first analyzed using the BETequation and the point B methods; these results were compared with those obtained using a new equation designed forexamining the case of multisite occupancy. The new model specifically accounts for sites that are left uncovered in thecase of adsorption by linear adsorbates. Of these three, only the last method gives essentially the same value for thespecific surface area of the substrate when different adsorbates are used to measure it. The other two, more traditional,approaches give values of the specific surface area that decrease as the length of the adsorbate used increases.