کد مقاله | کد نشریه | سال انتشار | مقاله انگلیسی | نسخه تمام متن |
---|---|---|---|---|
10378756 | 880762 | 2005 | 13 صفحه PDF | دانلود رایگان |
عنوان انگلیسی مقاله ISI
An EXAFS and TRLFS investigation on uranium(VI) sorption to pristine and leached albite surfaces
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کلمات کلیدی
موضوعات مرتبط
مهندسی و علوم پایه
مهندسی شیمی
شیمی کلوئیدی و سطحی
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چکیده انگلیسی
Uranium(VI) was sorbed to freshly ground and leached albite in batch and flow-through systems in the pH range 5.0-6.4. The uranium(VI) surface complexes were studied by extended X-ray absorption fine structure (EXAFS) spectroscopy and time-resolved laser-induced fluorescence spectroscopy (TRLFS). The EXAFS analysis of uranium(VI) sorbed on albite at pH 5.8 and 5â
Ãâ
10â6 M U(VI) showed one silicon atom at a USi distance of 3.09 Ã
, which is indicative of the formation of an inner-sphere, mononuclear, bidentate uranium(VI) surface complex, Si(O)2UO2, on the silicate tetrahedra of albite. Two additional uranium(VI) sorption complexes were detected by TRLFS at higher initial aqueous U(VI) concentrations. However, the structure of these surface complexes could not be derived from EXAFS, since the measured EXAFS spectra represent the average of two surface complex structures. In order to simulate U(VI) sorption onto weathered feldspar surfaces, albite was leached with 0.01 M HClO4, resulting in surface material similar to amorphous silica gel. EXAFS showed that the equatorial oxygen shell of uranium(VI) sorbed on this material at pH 5.0 and 5.8 was split in two distances of 2.23 and 2.44 Ã
. This indicates the formation of an inner-sphere surface complex.
ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: Journal of Colloid and Interface Science - Volume 282, Issue 2, 15 February 2005, Pages 293-305
Journal: Journal of Colloid and Interface Science - Volume 282, Issue 2, 15 February 2005, Pages 293-305
نویسندگان
Marcus Walter, Thuro Arnold, Gerhard Geipel, Andreas Scheinost, Gert Bernhard,