Thermodynamics of Carbon Dioxide Adsorption on the Protonic Zeolite H‐ZSM‐5

Abstract

Adsorption of carbon dioxide on H-ZSM-5 zeolite (Si:Al=11.5:1) was studied by means of variable-temperature FT-IR spectroscopy, in the temperature range of 310-365 K. The adsorbed CO(2) molecules interact with the zeolite Brønsted-acid OH groups bringing about a characteristic red-shift of the O-H stretching band from 3610 cm(-1) to 3480 cm(-1). Simultaneously, the nu(3) mode of adsorbed CO(2) is observed at 2345 cm(-1). From the variation of integrated intensity of the IR absorption bands at both 3610 and 2345 cm(-1), upon changing temperature (and CO(2) equilibrium pressure), the standard adsorption enthalpy of CO(2) on H-ZSM-5 is DeltaH(0)=-31.2(+/-1) kJ mol(-1) and the corresponding entropy change is DeltaS(0)=-140(+/-10) J mol(-1) K(-1). These results are discussed in the context of available data for carbon dioxide adsorption on other protonic, and also alkali-metal exchanged, zeolites.

CO2 adsorption in Y zeolite: a structural and dynamic view by a novel principal-component-analysis-assisted in situ single-crystal X-ray diffraction experiment

“…5). The values are in agreement with data reported for CO 2 in MFI zeolite (Armandi et al, 2009). The corresponding plot obtained using the PC1 scores as CO 2 amount estimator is reported in Fig.…”

“…The enthalpy and entropy of CO 2 adsorption were calculated as ÁH = À32 kJ mol À1 and ÁS = À100 J Kmol À1 , respectively. These values are consistent with those calculated from FT-IR data by Armandi et al (2009), thus demonstrating the possibility of obtaining thermodynamic data from in situ single-crystal diffraction. The enthalpy value is significant and involves systems (CO 2 and Y zeolite) with no toxicity, superb stability and chemical inertness.…”

Tailoring Metal–Organic Frameworks for CO2 Capture: The Amino Effect

“…[45] For this reason, the ñ 3 value observed in silicalite is taken as a reference because of its apolar framework. [39,45,58] However, although lacking in cations, silicalite is not lacking in possible adsorption sites, represented by silanols. By analyzing the data reported in Table 2, it is evident that, in spite of the weak interaction, a silanol would be able to shift the ñ 3 mode upwards by +3 cm À1 .…”

Variable‐Temperature IR Spectroscopic and Theoretical Studies on CO2 Adsorbed in Zeolite K‐FER

“…Aside from CCS, improved CO 2 adsorbents could find several other practical applications, such as removal of CO 2 from natural gas to improve its energy density [6] and purification of breathing air (e.g., in submarines and spacecraft for long-term space missions). [7] Among prospective porous solids for reversible CO 2 adsorption, metal-organic frameworks (MOFs) and related compounds, [8][9][10][11][12][13][14] porous carbons, [15][16][17][18][19] and zeolites [20][21][22][23][24][25][26][27][28][29][30][31][32] are the main types receiving current attention. For several reasons, zeolites are particularly well suited for fundamental studies aimed at detailed understanding of the gas-solid interactions that dictate adsorption thermodynamics, which is a main factor determining adsorbent performance: 1) zeolites have well-defined (and known) crystal structures, 2) they can easily undergo cation exchange, and 3) zeolites display a wide topological variety.…”