Article ID Journal Published Year Pages File Type
75681 Microporous and Mesoporous Materials 2010 4 Pages PDF
Abstract

Porous aluminum-trimesate (MIL-96), one of the metal–organic frameworks (MOFs), has been synthesized hydrothermally under autogeneous pressure in water as the solvent. The MIL-96 adsorbs nitrogen readily at liquid nitrogen temperature to show permanent porosity (SBET = 532 m2/g, SLangmuir = 700 m2/g). Moreover, the desorption of adsorbed nitrogen does not to show any hysteresis between the adsorption and desorption isotherms. A vapor-phase adsorption study (temperature: 30–110 °C) shows that MIL-96 can uptake aromatic compounds such as p-xylene, m-xylene and 1,3,5-TMB (trimethylbenzene). However, a larger molecule such as 1,3,5-TiPB (triisopropylbenzene) is only negligibly adsorbed on MIL-96. The adsorption rate of 1,3,5-TMB (even at a high temperature of 70 °C) is very slow compared with that of p-xylene (at 30 °C). Very interestingly, the adsorption capacity of 1,3,5-TMB increases with increasing adsorption temperature (up to 90 °C), which is very rare because an adsorption is usually an exothermic process. All of these results may be explained by the fact that the MIL-96 has a pore size similar to a kinetic diameter of 1,3,5-TMB. Moreover, the results may suggest that the framework of MIL-96 is flexible and the lattice vibrates more widely at high temperature to increase the effective pore size. The flexible structure of MIL-96 demonstrated in this study may enlarge the applications of MOFs for the storage of chemicals and controlled release such as drug delivery.

Related Topics
Physical Sciences and Engineering Chemical Engineering Catalysis
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