High pressure adsorption of hydrogen, nitrogen, carbon dioxide and methane on the metal-organic framework HKUST-1

High pressure adsorption phenomena are discussed for different gases on HKUST-1 (Cu-3(BTC)(2), commercially available product Basolite (TM) C300). Sorption isotherms for hydrogen, nitrogen, methane and carbon dioxide on HKUST-1 were measured in the temperature range of 273-343 K and at pressures up to 50 MPa. The calculated surface excess adsorption capacities for all four adsorptive are one of the highest reported in the literature for HKUST-1 samples. All surface excess data were further calculated from the experimental data by using the helium buoyancy correction. A detailed description was given. Also a procedure to calculate the absolute amount adsorbed from the surface excess amount by using two different models is shown. Using one model, the density and the volume of the adsorbed phase can be calculated. The density of the adsorbed phase rho(ads) corresponds to the liquid density of the adsorptive at its boiling point rho(liq,BP). In case of hydrogen no excess maximum was found up to 50 MPa, so that one model could not be applied. Finally, the isosteric heat of adsorption for each gas was calculated by using the Clausius-Clapeyron equation. (C) 2010 Elsevier Inc. All rights reserved.