Article

Different adsorption behaviors of methane and carbon dioxide in the isotypic nanoporous metal terephthalates MIL-53 and MIL-47

Aix-Marseille Université, Marsiglia, Provence-Alpes-Côte d'Azur, France
Journal of the American Chemical Society (Impact Factor: 11.44). 11/2005; 127(39):13519-21. DOI: 10.1021/ja054668v
Source: PubMed

ABSTRACT A distinct step in the isotherm occurs during the adsorption of CO2 on MIL-53 at 304 K. Such behavior is neither observed during the adsorption of CH4 on MIL-53 nor during the adsorption on the isostructural MIL-47. This phenomenon seems to be due to a different mechanism than that of previous adsorption steps on MOF samples. It is suggested that a breathing behavior is induced in MIL-53 during CO2 adsorption.

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    • "The size of the pores and the surface areas of MOFs were found to be larger than those determined for zeolites (microporous aluminosilicate minerals commonly used as commercial adsorbents). Furthermore, the framework flexibility of MOFs and the presence of unsaturated metal sites (undercoordinated open sites) has been suggested to have a vital role in their interaction with some molecules.[87] [88] These are the main reasons for the growing scientific interest in MOFs since the first example of this class of porous material was reported. "
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    • "Conventional commercial technologies for CO 2 removal are not cost-effective and they suffer from serious energy penalties, and yield poor absorption efficiencies. Therefore development of stable and recyclable solid adsorbents that could adsorb CO 2 efficiently and contribute to the process economy would be highly desired [1] [2] [3] [4] [5] [6] [7] [8] [9] [10]. A variety of solid materials that readily adsorb CO 2 are available , including metal oxides and mixed metal oxides [11] [12] [13], high-surface-area porous materials, such as zeolites [14] [15] [16] [17], carbon [18], metal-organic frameworks (MOFs) [19] [20] [21], organosilica, and surface-modified silica [22] [23] [24]. "
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    • ") octahedral interconnected by the dicarboxylate groups [16] [17]. This, results in a 3D metal-organic framework containing one single pore size with 1D diamond shaped channels with pores of free diameter close to 0.85 nm [18]. However, the MIL-53 has shown reversible structural changes due to the framework interaction with guest molecules , reported as a " breathing effect " of the pores. "
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