Thermodynamics of gas adsorption on fractal surfaces of heterogeneous microporous solids

Publisher Website
Google Scholar
Abstract
Thermodynamic equations are derived for physical adsorption of gases and vapors on fractalsurfaces of heterogeneous microporous solids. The influence of surfacegeometry on gas adsorption on a microporous solid is studied by analyzing the dependence of the differential molar enthalpy ΔH, the immersion enthalpy ΔH im, and the differential molar entropy ΔS on the fractal dimension D, which is used to characterize the surface irregularity. It is shown that −ΔH, −ΔH im, −ΔS, and the average adsorption potential Ā increase as the fractal dimension of the surface accessible for adsorption increases. The dependence of these thermodynamic quantities on the fractal dimension D is attributed to the fact that the fraction of small micropores in microporous solids increases as the fractal dimension D increases.