Sequestration of the tributyl phosphate complex of europium nitrate in the clay hectorite. A {sup 31}P NMR study
- Northern Arizona Univ., Flagstaff, AZ (United States)
- Los Alamos National Lab., NM (United States)
Application of {sup 31}P NMR to distinguish Eu(NO{sub 3}){sub 3}-complexed tributyl phosphate from uncomplexed tributyl phosphate (TBP) facilitates an understanding of the fate of these species in the clay hectorite. Solution {sup 31}P NMR studies show dramatic shifts of {minus}156.0 to {minus}172.9 ppm for Eu(NO{sub 3}){sub 3}6H{sub 2}O dissolved in TBP at TBP:Eu ratios 1:1 to 1:2.5. Pure TBP exhibits {sup 31}P chemical shift of {minus}0.3 ppm. Mixtures with higher TBP:Eu ratios display lines progressively downfield of {minus}156.0 ppm, reflecting exchange of complexed and free TBP. The Eu(NO{sub 3}){sub 3}-complexed TBP adsorbed into hectorite displays a {sup 31}P chemical shift of {minus}180.7 to {minus}193.8 ppm. Clays adsorbed with solutions that are 3.1, 5:1 and 7:1 TBP:Eu display peaks due to complex as well as peaks in the range {minus}4 to {minus}6 ppm attributed to uncomplexed TBP. No evidence of exchange is observed. Spectra of the TBP-adsorbed clay give a TBP line at {minus}0.7 ppm which changes slightly to {minus}-5.0 after exchange with Eu(NO{sub 3}){sub 3}. The Eu(NO{sub 3}){sub 3}-exchanged hectorite displays a line at {minus}17.6 ppm after adsorption of TBP. Neither of the latter two samples show indication of complex formation. The hectorite samples exposed to TBP or the complex display (001) d spacings of 17.9-18.4 A compared to 12.3-12.5 A for hectorite which has not been exposed to TBP. 26 refs., 5 figs., 3 tabs.
- Sponsoring Organization:
- USDOE
- OSTI ID:
- 35457
- Journal Information:
- Journal of Physical Chemistry, Vol. 99, Issue 12; Other Information: PBD: 23 Mar 1995
- Country of Publication:
- United States
- Language:
- English
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