| Abstract
| - An approach to adsorption in micropores is developed on the basisof the condensation approximationmethod. In the case of micropores with half-width less than 0.8nm, a volume filling of the single microporeand a two-dimensional (2D) condensation on its walls occur at the samecritical pressure, pc. Fromthispoint of view, the statistical mechanical theories of adsorption onhomogeneous surfaces considering lateralinteractions may be taken to be a starting point to the description ofphysical adsorption in micropores.The increased well depth, ε*, in micropores causes the 2Dcondensation on their surface to occur at asmaller pc compared with a nonporous surface.As a consequence, the overall adsorption isotherm isdetermined by the distribution of micropore walls over adsorptionenergies resulting from a randomdistribution of micropore widths, d. Proceeding from amodel of heterogeneity and the normal distributionof micropore widths, the log-normal distributions of micropore volumesover ε* and pc are obtained, andan occupied adsorption volume as a function of outer pressures isfound. This approach has been successfullyapplied to seven benzene adsorption isotherms on four species of activecarbons. It provides a correctdescription of equilibrium data in a wide temperature range, leads toreasonable distribution function ofε* and d, and gives values of an average micropore sizethat are close to the experimental one.
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