(395be) Multicomponent Adsorption Equilibria On Cu-Based MOF-Materials

Multicomponent Adsorption Equilibria on Cu-Based MOF-Materials

J. Möllmer, A. Möller, Institut für Nichtklassiche Chemie e.V., Leipzig/Germany

R. Staudt, University of Applied Sciences, Offenburg/Germany

Since the development of metal-organic frameworks (MOFs), the interest in studying specific adsorption interactions are gaining importance.[1] Starting with characterization of porous MOFs and followed by intensive study of gas storage applications, e.g., storage of hydrogen, carbon dioxide or methane, the current research interest is on multicomponent adsorption equilibria. In particular, for gas separation processes, the information about the adsorption equilibria of mixtures are of major importance. Thus, several groups have studied binary adsorption by dynamic methods, such as breakthrough curves or gravimetric method without a circulation pump.[3]
Here, three Cu-containing MOFs, i.e. the well known material Cu3(BTC)2 (copper -
1,3,5-tricarboxylic acid, HKUST-1)[2] and two MOFs with a triazole ligand, in particular
the highly flexible MOF 3 [(Cu4(µ4-O)(µ2-OH)2(Me2trzpba)4][4] and a new Cu-based MOF 3 [Cu(Me-4py-trz-ia)][5], were used for pure gas and mixed gas adsorption experiments using the volumetric-chromatographic method. More precisely, CO2 and
CH4 pure gas adsorption experiments were carried out at temperatures between
273 K to 323 K and pressures up to 3 MPa. The IAST-model was used to calculate

binary adsorption data from the pure gas isotherms. These data were further compared to experimental binary adsorption data, which were measured with a static volumetric system. Furthermore, the selectivity for adsorption of CO2 over CH4 was calculated and discussed in the context of the adsorption potential based on the accessible Cu-sites of these MOFs. The results provide evidence for the high potential of the investigated MOFs for gas separation applications, here, of CO2 separation from methane, especially at elevated pressures.

Tab. 1: Binary adsorption of CO2 and CH4 on Cu3(BTC)2 at 298 K and 0.54 MPa (left side -- adsorption isotherms at 298 K; right side - partial loading). Acknowledgements

The authors thank D. Lässig and J. Lincke (Institute of Inorganic Chemistry, University of Leipzig) for preparing the MOF

materials. The Deutsche Forschungsgemeinschaft (DFG-Projekt SPP 1362 MOF STA428/17-1) is also gratefully acknowledged. References

[1] O.M. Yaghi, H. Li, J. Am. Chem. Soc. 117 (1995) 10401.

[2] S.-Y. Chui, S. M.-F. Lo, J.P.H. Charmant, A.G. Orpen, I.D. Williams, Science 283 (1999) 1148. [3] L. Hamon, E. Jolimaitre, G.D. Pirngruber, Ind.Eng.Chem.Res. 49 (2010) 7497.

[4] J. Lincke, D. Lässig, J. Möllmer, C. Reichenbach, A. Puls, A. Möller, R. Gläser, G. Kalies, R. Staudt, H. Krautscheid, Micropor.Mesoporous Materials 2010, submitted.

[5] D. Lässig, J. Lincke, J. Möllmer, C. Reichenbach, G. Kalies, R Gläser, R. Staudt, H. Krautscheid, in preparation.