ADSORPTION MEASUREMENTS OF ARGON, NEON, KRYPTON, NITROGEN, AND METHANE ON ACTIVATED CARBON UP TO 650MPA

The physisorption of argon, krypton, neon, nitrogen, and methane on GAC activated carbon has been measured in the above critical region by a dielectric method. The measurements were done at room temperature and at pressures up to 650 MPa corresponding to reduced densities of up to 3.25. With the exception of nitrogen, all the measured excess adsorption isotherms show a similar behavior. They exhibit a maximum followed by a downward straight line intercepting the bulk density axis at around the liquid density of the adsorbate in the normal liquid range. The surface excess adsorption isotherms are well represented over the entire density range by Fischer's three-parameter integral equation. The results are also characterized in terms of the critical parameters and the reduced variables of the adsorbates.