(242e) Simulated and Experimental Adsorption Equilibria of Light Alkanes In MIL-53(Al) Metal-Organic Framework

Over the past decade, a large number of hybrid organic-inorganic porous solids belonging to a new class of structured nanoporous materials—metal-organic frameworks (MOFs)—have been synthesized and structurally characterized. Due to their high porosity, high adsorption capacity, and thermal stability, these materials have shown great potential for applications in gas storage, gas separation, and catalysis. Porous aluminum terephthalate (MIL-53) is a MOF material that adsorbs large amounts of gases, such as CH4 and CO2 [15, 16]. Although the crystal structures of MOFs are typically composed of rigid frameworks, they can demonstrate significant structural distortions upon adsorption/desorption of host molecules; MIL-53 is a typical example of this: it displays a ‘‘breathing’’ character, corresponding to a reversible transition between a large-pore and a narrow-pore structure by adsorbing different guest molecules [1 ]or by temperature changes [2] alone. Because of this, MIL-53 has received much attention [3].

In the present work, we have experimentally measured the single-component adsorption equilibria of alkanes and alkenes C1-C4 on MIL-53(Al) at 303 K, 323 K, and 353 K, over a broad pressure range, 10 mbar–70 bar. In order to understand the thermodynamics of confinement of these adsorbates in the porous structure of MIL-53, we performed grand canonical Monte Carlo (GCMC) simulations and shown that the molecular simulation data predicts very well the experimental adsorption data. Using molecular simulation we explore the factors that influence the adsorption behavior of gases at different temperatures and pressures in MIL-53, providing a more comprehensive understanding of this MOF as a gas storage medium.

References

(1) T. Loiseau, C. Serre, C. Huguenard, G. Fink, F. Taulelle, M. Henry, T. Bataille, G. Férey, Chem. Eur. J. 10 (2004) 1373

(2) Y. Liu, J.-H. Her, A. Dailly, A.J. Ramirez-Cuesta, D.A. Neumann, C.M. Brown, JACS 130 (2008) 11813.

(3) T.K. Trung, P. Trens, N. Tanchoux, S. Bourrelly, P. L. Llewellyn, S. Loera-Serna, C. Serre, T. Loiseau, F. Fajula, G. Férey, JACS 130 (2008) 16926.