Hydrothermal synthesis and characterization of uranium-containing MCM-48 samples

Kumar, Dharmesh ; Pillai, K. T. ; Sudersanan, V. ; Dey, G. K. ; Gupta, N. M. (2003) Hydrothermal synthesis and characterization of uranium-containing MCM-48 samples Chemistry of Materials, 15 (20). pp. 3859-3865. ISSN 0897-4756

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Official URL: http://pubs.acs.org/doi/abs/10.1021/cm030269s

Related URL: http://dx.doi.org/10.1021/cm030269s


MCM-48 samples containing uranium (U-MCM-48) to the extent of 1 to 6 wt % were synthesized hydrothermally and characterized using powder XRD, 29Si MAS NMR, FTIR spectroscopy, DR UV-Vis spectroscopy, N2 sorption, and TEM techniques. These analyses confirmed the formation of an ordered cubic-phase MCM-48 mesomaterial where the uranium existed in the hexavalent state forming a local uranate type structure. A part of the uranyl groups were found to be incorporated in the framework positions, while the rest were anchored on to the wall of the host silica matrix. Also, the U-MCM-48 samples exhibited an enlargement of the cubic cell unit as well as an increase in the degree of cross-linking, as revealed by XRD and MAS NMR results. The samples exhibited N2 sorption isotherms of type IV and an increase was observed in the pore diameter as a result of uranium incorporation. TEM investigation revealed that although U-MCM-48 samples were of cubic symmetry similar to that of Si-MCM-48, some distortion in the pore structure was clearly noticeable. Furthermore, in case of the samples with U loading of 6 wt %, formation of nanocrystallites of α -U3O8 was also detected after calcination and such samples consisted of a multiple-size pore system.

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ID Code:82465
Deposited On:10 Feb 2012 15:33
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