Experimental and Theoretical Studies of Supercritical Methane Adsorption in the MIL-53(Al) Metal Organic Framework

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• 作者：Andriy Lyubchyk ; Isabel A. A. C. Esteves ; Fernando J. A. L. Cruz ; Jos茅 P. B. Mota
• 刊名：Journal of Physical Chemistry C
• 出版年：2011
• 出版时间：October 27, 2011
• 年：2011
• 卷：115
• 期：42
• 页码：20628-20638
• 全文大小：1075K
• 年卷期：v.115,no.42(October 27, 2011)
• ISSN：1932-7455

文摘

The adsorption equilibrium properties of supercritical methane in the large-pore (lp) structure of the MIL-53(Al) metal organic framework were studied experimentally by gravimetric adsorption and theoretically by grand canonical Monte Carlo (GCMC) simulation. The adsorption experiments span a broad range of pressures (0.01鈥? MPa) and temperatures (303鈥?53 K). In our molecular simulation work, MIL-53lp(Al) is assumed to have a perfect, rigid lattice, and both fluid鈥揻luid and solid鈥揻luid interactions are modeled using the TraPPE-UA force field. The adsorption isotherms and isosteric heats of adsorption predicted by GCMC simulation, without any reparametrization of the TraPPE-UA force field parameters, are in good agreement with the experimental measurements. Our molecular simulations predict that the amount of methane adsorbed in the porous framework of MIL-53lp(Al) at 298.15 K and 3.5 MPa is 5.79 mol/kg, yielding a methane storage capacity of 132.6 v/v (volumes of stored gas, measured at standard conditions, per storage volume) for a monolithic block and 107.2 v/v for the theoretical limit of a close-packing of uniform spherical particles. For an isothermal (298.15 K) discharge cycle between 3.5 and 0.136 MPa, the predicted net deliverable capacity is 114.0 (v/v)_net for a monolith and 93.1 (v/v)_net for a close-packed bed. If, however, the storage system is operated at 253 K, the net storage capacity of a monolithic block of MIL-53(Al) increases to a value that is very close to the DOE target of 150 (v/v)_net.