An investigation of the interactions of Eu3+ and Am3+ with uranyl minerals: implications for the storage of spent nuclear fuel.
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2016Access:
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S. Biswas, R. Steudner, M. Schmidt, C. McKenna, L. L. Vintro, B. Twamley and R.J. Baker, An investigation of the interactions of Eu3+ and Am3+ with uranyl minerals: implications for the storage of spent nuclear fuel., Dalton Transactions, 45, 2016, 6383 - 6393Download Item:
Abstract:
The reaction of a number of uranyl minerals of the (oxy)hydroxide, phosphate and carbonate types with
Eu(
III
), as a surrogate for Am(
III
), have been investigated. A photoluminescence study shows that Eu(
III
) can
interact with the uranyl minerals Ca[(UO
2
)
6
(O)
4
(OH)
6
]·8H
2
O (becquerelite) and A[UO
2
(CO
3
)
3
]·
x
H
2
O
(A/
x
=K
3
Na/1, grimselite; CaNa
2
/6, andersonite; and Ca
2
/11, liebigite). For the minerals
[(UO
2
)
8
(O)
2
(OH)
12
]·12H
2
O (schoepite), K
2
[(UO
2
)
6
(O)
4
(OH)
6
]·7H
2
O (compreignacite), A[(UO
2
)
2
(PO
4
)
2
]·8H
2
O
(A = Ca,
meta
-autunite; Cu,
meta
-torbernite) and Cu[(UO
2
)
2
(SiO
3
OH)
2
]·6H
2
O (cuprosklodowskite) no
Eu(
III
) emission was observed, indicating no incorporation into, or sorption onto the structure. In the
examples with Eu
3+
incorporation, sensitized emission is seen and the lifetimes, hydration numbers and
quantum yields have been determined. Time Resolved Laser Induced Fluroescence Spectroscpoy (TRLFS)
at 10 K have also been measured and the resolution enhancements at these temperatures allow further
information to be derived on the sites of Eu(
III
) incorporation. Infrared and Raman spectra are recorded,
and SEM analysis show signi
fi
cant morphology changes and the substitution of particularly Ca
2+
by Eu
3+
ions. Therefore, Eu
3+
can substitute Ca
2+
in the interlayers of becquerelite and liebigite and in the struc-
ture of andersonite, whilst in grimselite only sodium is exchanged. These results have guided an investi-
gation into the reactions with
241
Am on a tracer scale and results from gamma-spectrometry show that
becquerelite, andersonite, grimselite, liebigite and compreignacite can include americium in the structure.
Shifts in the U
v
O and C
–
O Raman active bands are similar to that observed in the Eu(
III
) analogues and
Am(
III
) photoluminescence measurements are also reported on these phases; the Am
3+
ion quenches the
emission from the uranyl ion
Sponsor
Grant Number
Irish Research Council (IRC)
Author's Homepage:
http://people.tcd.ie/bakerrjhttp://people.tcd.ie/mckennc6
Description:
PUBLISHED
Author: Baker, Robert; Mc Kenna, Cora
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Series/Report no:
Dalton Transactions45
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Full text availableKeywords:
uranyl mineralsDOI:
http://dx.doi.org/10.1039/C6DT00199HMetadata
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