A MODIFIED APPROACH FOR ESTIMATING PSEUDO-VAPOR PRESSURES IN THE APPLICATION OF THE DUBININ-ASTAKHOV EQUATION

High pressure adsorption data of methane and hydrogen on four micropor ous carbons were obtained at supercritical temperatures. The data were analyzed on the basis of the Potential Theory using the Dubinin-Astak hov (D-A) equation. The method for estimating pseudo-vapor pressures p roposed by Dubinin resulted in characteristic curves for methane but f ailed for the hydrogen data. A more general form of Dubinin's method f or estimating pseudo-vapor pressures is proposed. This approach introd uces a parameter, k, that accounts for interactions in the adsorbate-a dsorbent systems under consideration. It was found that the modified a pproach to the use of the D-A equation leads to reliable prediction of both methane and hydrogen data.