Autié Castro G.1, de Oliveira Jardim E.2, Reguera E.1,3, Vilarrasa-García E.2, Rodríguez-Castellón E.4*, Cavalcante Jr. C.L.2
1.Institute of Science and Technology of Materials (IMRE), University of Havana, 10400 Havana, Cuba.
2.Universidade Federal do Ceará, Department of Chemical Engineering, GPSA-Group of Research in Separations by Adsorption, Campus do Pici, 60455760 Fortaleza, Ceará, Brazil.
3. Center for Applied Science and Advanced Technologies of IPN, 11500, Mexico, DF.
4. Department of Inorganic Chemistry, Crystallography and Mineralogy, Faculty of Sciences, University of Malaga, Campus de Teatinos, 29071, Malaga, Spain.
Abstract: CH4 and CO2 adsorption capacity at 25, 50 and 75°C was evaluated in two metal-organic frameworks: Al-BDC and ZIF-8, the later with zeolite topology. Adsorption experiments were carried out under static conditions using a gravimetric suspension balance until 40 bar of pressure. Adsorption isotherms of type I were obtained for both materials showing high adsorption capacity values. ZIF-8 exhibited the higher uptake value for both CH4 and CO2 (4.9 and 8.5 mmol g-1, respectively). The Toth equilibrium model was used to fit experimental isotherms in order to obtain qm (maximum adsorption capacity) and t (related to energetical heterogeneity of the surface). Isosteric heats of adsorption were also calculated by Clausius-Clapeyron equation.
Keywords: Adsorption, ZIFs, MOFs, adsorption heats, adsorption isotherm.
Pages: 234 – 246 | Full PDF Paper