Controlling the Adsorption Enthalpy of CO2 in Zeolites by Framework Topology and Composition

Authors

  • Lukáš Grajciar,

    1. Department of Physical and Macromolecular Chemistry, Faculty of Science, Charles University in Prague, Hlavova 2030, CZ-128 40 Prague 2 (Czech Republic), Fax: (+420) 221-951-289
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  • Prof. Jiří Čejka,

    1. J. Heyrovský Institute of Physical Chemistry, Academy of Sciences of the Czech Republic, Dolejškova 3, Prague 8, 182 23 (Czech Republic)
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  • Dr. Arnošt Zukal,

    1. J. Heyrovský Institute of Physical Chemistry, Academy of Sciences of the Czech Republic, Dolejškova 3, Prague 8, 182 23 (Czech Republic)
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  • Prof. Carlos Otero Areán,

    1. Department of Chemistry, University of the Balearic Islands, Palma de Mallorca (Spain)
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  • Gemma Turnes Palomino,

    1. Department of Chemistry, University of the Balearic Islands, Palma de Mallorca (Spain)
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  • Prof. Petr Nachtigall

    Corresponding author
    1. Department of Physical and Macromolecular Chemistry, Faculty of Science, Charles University in Prague, Hlavova 2030, CZ-128 40 Prague 2 (Czech Republic), Fax: (+420) 221-951-289
    • Department of Physical and Macromolecular Chemistry, Faculty of Science, Charles University in Prague, Hlavova 2030, CZ-128 40 Prague 2 (Czech Republic), Fax: (+420) 221-951-289
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Abstract

Zeolites are often investigated as potential adsorbents for CO2 adsorption and separation. Depending on the zeolite topology and composition (Si/Al ratio and extra-framework cations), the CO2 adsorption heats at low coverages vary from −20 to −60 kJ mol−1, and with increasing surface coverage adsorption heats either stay approximately constant or they quickly drop down. Experimental adsorption heats obtained for purely siliceous porous solids and for ion-exchanged zeolites of the structural type MFI, FER, FAU, LTA, TUN, IMF, and -SVR are discussed in light of results of periodic density functional theory calculations corrected for the description of dispersion interactions. Key factors influencing the stability of CO2 adsorption complexes are identified and discussed at the molecular level. A general model for CO2 adsorption in zeolites and related materials is proposed and data reported in literature are evaluated with regard to the proposed model.

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