Uranyl interaction with the hydrated (001) basal face of gibbsite:A combined theoretical and spectroscopic study

The sorption of uranyl cations and water molecules on the basal (001) face of gibbsite was studied by combining vibrational and fluorescence spectroscopies together with density functional theory (DFT) computations. Both the calculated and experimental values of O-H bond lengths for the gibbsite bul...

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Bibliographic Details
Published in:The Journal of chemical physics 2008-12, Vol.129 (24), p.244704-244704-10
Main Authors: Veilly, Edouard, Roques, Jérôme, Jodin-Caumon, Marie-Camille, Humbert, Bernard, Drot, Romuald, Simoni, Eric
Format: Article
Language:English
Subjects:
Adsorption
Aluminum Hydroxide - chemistry
Hydrogen-Ion Concentration
Hydroxides - chemistry
Models, Molecular
Molecular Conformation
Pressure
Quantum Theory
Spectrometry, Fluorescence
Spectrum Analysis, Raman
Surface Properties
Uranium Compounds - chemistry
Water - chemistry
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Summary:The sorption of uranyl cations and water molecules on the basal (001) face of gibbsite was studied by combining vibrational and fluorescence spectroscopies together with density functional theory (DFT) computations. Both the calculated and experimental values of O-H bond lengths for the gibbsite bulk are in good agreement. In the second part, water sorption with this surface was studied to take into account the influence of hydration with respect to the uranyl adsorption. The computed water configurations agreed with previously published molecular dynamics studies. The uranyl adsorption in acidic media was followed by time-resolved laser-induced fluorescence spectroscopy and Raman spectrometry measurements. The existence of only one kind of adsorption site for the uranyl cation was then indicated in good agreement with the DFT calculations. The computation of the uranyl adsorption has been performed by means of a bidentate interaction with two surface oxygen atoms. The optimized structures displayed strong hydrogen bonds between the surface and the -yl oxygen of uranyl. The uranium-surface bond strength depends on the protonation state of the surface oxygen atoms. The calculated U - O surface bond lengths range between 2.1-2.2 and 2.6 - 2.7   Å for the nonprotonated and protonated surface O atoms, respectively.
ISSN:0021-9606
1089-7690
DOI:10.1063/1.3042142