Preferential adsorption of water is a major problem in the processes of CO2 adsorption on molecular sieves. Adsorption and desorption of CO2 on partially hydrated zeolite Na-Y have been monitored by in situ synchrotron X-ray powder diffraction. The structural refinement of the CO2-saturated diffraction pattern highlighted the formation of tetrameric CO2 clusters connected by water bridges to the sodium cations of two adjacent faujasite supercages. The CO2 desorption was followed by collecting a series of diffraction patterns upon heating from room temperature up to 350 °C. The hydrated CO2 clusters are completely desorbed between 250 °C and 350 °C. This high thermal stability suggests that the formation of hydrated complexes could represent a potentially important mechanism of retention of CO2 during the regeneration of CO2 adsorbents.

Evidence for the formation of stable CO2 hydrates in zeolite Na-Y: Structural characterization by synchrotron X-ray powder diffraction

ARLETTI, Rossella;GIGLI, LARA;
2016-01-01

Abstract

Preferential adsorption of water is a major problem in the processes of CO2 adsorption on molecular sieves. Adsorption and desorption of CO2 on partially hydrated zeolite Na-Y have been monitored by in situ synchrotron X-ray powder diffraction. The structural refinement of the CO2-saturated diffraction pattern highlighted the formation of tetrameric CO2 clusters connected by water bridges to the sodium cations of two adjacent faujasite supercages. The CO2 desorption was followed by collecting a series of diffraction patterns upon heating from room temperature up to 350 °C. The hydrated CO2 clusters are completely desorbed between 250 °C and 350 °C. This high thermal stability suggests that the formation of hydrated complexes could represent a potentially important mechanism of retention of CO2 during the regeneration of CO2 adsorbents.
2016
228
248
255
www.elsevier.com/inca/publications/store/6/0/0/7/6/0
CO2 adsorption; CO2 desorption; High temperature structural studies; Na-faujasite; Synchrotron X-ray powder diffraction; Materials Science (all); Mechanics of Materials; Chemistry (all); Condensed Matter Physics
Arletti, Rossella; Gigli, Lara; Di Renzo, Francesco; Quartieri, Simona
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/2318/1564645
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