Dual Langmuir Kinetic Model for Adsorption in Carbon Molecular Sieve Materials

A model of adsorption in carbon molecular sieve materials (CMS) is presented in this paper. Adsorption kinetics is modeled as a series of two consecutive processes: nonselective adsorption of molecules in meso-supermicropores followed by the movement of such adsorbed molecules into small micropores through the pore mouth barriers. The rate of nonselective adsorption is found to be of the same magnitude for different probe molecules, and it is the second process that renders CMS the kinetic separation abilities. The model describes the experimental data very well, and the activation energy of the second step is analyzed with the aid of the molecular potential calculation to derive the effective width of the micropore mouth.