CALCULATION OF ADSORPTION ENERGIES IN CARBON MICROPORES

Adsorption energies for different surface and pore configurations were calculated by summing the Lennard-Jones potential for the interaction of an adsorbate molecule with the carbon surface. The calculations provide information on the adsorption potential as a function of pore configuration and spacing from which an energy distribution for physisorption was estimated. The results of the calculations also show that restricted diffusion occurs only for a small range of pore sizes between approximately 6.4 and 5.8 angstrom; in larger pores, the adsorbate is mobile, whereas pores smaller than 5.8 angstrom are largely inaccessible. A diffusion model for microporous carbons is proposed where the diffusion rate depends on the rate of transport from one adsorption site to an adjacent one and not on the rate of transport within a pore itself.