Modeling Carbon Dioxide Adsorption on Microporous Substrates: Comparison between Cu-BTC Metal-Organic Framework and 13X Zeolitic Molecular Sieve

In this work, CO2 adsorption on a laboratory-synthesized polymeric copper(II) benzene-1,3,5-tricarboxylate (Cu-BTC) metal-organic framework was modeled by means of the semiempirical Sips equation in order to obtain parameters of engineering interest. Produced Cu-BTC samples were characterized by X-ray diffraction, thermogravimetry, and microporosimetric analysis; high crystallinity and very high specific surface area and pore volume were found. CO2 adsorption isotherms on Cu-BTC were evaluated at T = (283, 293, 318, and 343) K for p <= 1 bar by means of a volumetric technique. In order to establish a comparison, CO2 adsorption isotherms on samples of commercial 13X zeolite were determined under the same experimental conditions and then modeled in the same way as those for Cu-BTC. The modeling and experimental results indicated that relative to 13X zeolite, Cu-BTC showed higher CO2 adsorption capacities at near-ambient temperature and a lower heat release during the adsorption phase.