Chromatographic measurements were made for nitrogen adsorption on molecular-sieving carbons at 60, 100 and 150°C for several different nitrogen surface coverages.
Apparent adsorption equilibrium constants were determined from the retention times of the peaks for different concentrations, and the adsorption equilibrium isotherms were then determined. The peak width gave the intra-microparticle diffusivity where the effects of all the other possible transport processes were taken into account.
The strong dependence of the diffusivity on the amount adsorbed was explained in terms of chemical potential gradient as a driving force of the diffusion.