Co-adsorption and separation of CO2-CH4 mixtures in the highly flexible MIL-53(Cr) MOF.
The present study attempts to understand the use of the flexible porous chromium terephthalate Cr(OH)(O(2)C-C(6)H(4)-CO(2)) denoted MIL-53(Cr) (MIL = Material from Institut Lavoisier) for the separation of mixtures of CO(2) and CH(4) at ambient temperature. The coadsorption of CO(2) and CH(4) was studied by a variety of different techniques. In situ synchrotron X-ray Powder Diffraction allowed study of the breathing of the solid upon adsorption of the gas mixtures and simultaneously measured Raman spectra yielded an estimation of the adsorbed quantities of CO(2) and CH(4), as well as a quantification of the fraction of the narrow pore (NP) and the large pore (LP) form of MIL-53. Quantitative coadsorption data were then measured by gravimetry and by breakthrough curves. In addition, computer simulation was performed to calculate the composition of the adsorbed phase in comparison with experimental equilibrium isotherms and breakthrough results. The body of results shows that the coadsorption of CO(2) and CH(4) leads to a similar breathing of MIL-53(Cr) as with pure CO(2). The breathing is mainly controlled by the partial pressure of CO(2), but increasing the CH(4) content progressively decreases the transformation of LP to NP. CH(4) seems to be excluded from the NP form, which is filled exclusively by CO(2) molecules. The consequences in terms of CO(2)/CH(4) selectivity and the possible use of MIL-53(Cr) in a PSA process are discussed.
Hamon
Lomig
L
IFP, Direction Catalyse et Séparation, 69360 Solaize, France.
Llewellyn
Philip L
PL
Devic
Thomas
T
Ghoufi
Aziz
A
Clet
Guillaume
G
Guillerm
Vincent
V
Pirngruber
Gerhard D
GD
Maurin
Guillaume
G
Serre
Christian
C
Driver
Gordon
G
van Beek
Wouter
W
Jolimaître
Elsa
E
Vimont
Alexandre
A
Daturi
Marco
M
Férey
Gérard
G
D000327:Adsorption; D002245:Carbon Dioxide / Q000737:chemistry* / Q000302:isolation & purification; D008697:Methane / Q000737:chemistry* / Q000302:isolation & purification; D013059:Spectrum Analysis, Raman; D014961:X-Ray Diffraction
D002245:Carbon Dioxide; D008697:Methane