抄録
The adsorption equation, which includes three parameters, has been derived presuming that the 1st layer is localized adsorption while the admolecules in an upper adphase region over the monolayer behave like compressed gas molecules, i. e. nonlocalized adsorption. This adsorption equation reseelted to the Hüttig-type adsorption equation presuming that the upper adphase region over the 1st layer is a liquid. This adsorption equation can predict the experimental isotherms. There may be classified as extended Type I isotherms where the amount adsorbed increases gently even after completion of the monolayer and shows a finite value of adsorbed amount at saturation vapor pressure. The equation can be used to predict the isotherms throughout nearly the entire range of relative pressure. The reasonable surface area, adsorption constant and surface fraction at saturation vapor pressure are found to be obtained from the application of the experimental isotherms to the adsorption equation thus derived. The BDDT double-layer adsorption equation derived from the model where both the monolayer and the upper adphase region over the 1st layer obeyed the localized adsorption model results in a Langmuir-type isotherm and predicts isotherms appreciably smaller than those of the experiment. The surface areas obtained when using a three-parameter adsorption equation show a much more reasonable interpretation than that from the BDDT double-layer adsorption equation. Thus, the property of the upper adphase region over the 1st layer is percieved to be a non-localized property in which admolecules in this region behave like a compressed gas molecule.
