talspeak curve: an illustration of a see-saw effect in separations · 2012-05-24 · talspeak...
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TALSPEAK CURVE: AN ILLUSTRATION OF A SEE-SAW EFFECT IN SEPARATIONS
ACTINIDE AND FISSION PRODUCT PARTITIONING AND TRANSMUTATION, ISBN 978-92-64-99174-3, © OECD 2012 1
TALSPEAK curve: An illustration of a see-saw effect in separations
Abstract
TALSPEAK CURVE: AN ILLUSTRATION OF A SEE-SAW EFFECT IN SEPARATIONS
2 ACTINIDE AND FISSION PRODUCT PARTITIONING AND TRANSMUTATION, ISBN 978-92-64-99174-3, © OECD 2012
Introduction
Scheme 1: Structures of key components of TALSPEAK-type actinide/lanthanide separation, i.e. diethylenetriamine-N,N,N’,N”,N”-pentaacetic acid and di(2-ethylhexyl)phosphoric acid
N
N N
O
O O
O
O
OH
OH
OH
OH
OH
DTPA
OHOR
RO
O
P
R:
DTPA
HDEHP
TALSPEAK CURVE: AN ILLUSTRATION OF A SEE-SAW EFFECT IN SEPARATIONS
ACTINIDE AND FISSION PRODUCT PARTITIONING AND TRANSMUTATION, ISBN 978-92-64-99174-3, © OECD 2012 3
Figure 1: Detail of the origins of the thermodynamic balance established between DTPA and HDEHP
(a) Opposing thermodynamic forces in the TALSPEAK separation as quantified for lanthanide elements by extraction constants (HDEHP) and complex dissociation constants (DTPA), plotted as a function of reverse ionic radius; for extraction constants,
organic – HDEHP in n-dodecane, aqueous – 1.0 M (H+,Na
+)ClO4; dissociation constants were taken from NIST database
(b) Final liquid-liquid distribution of actinides and lanthanides – a result of the thermodynamic struggle for balance between DTPA and HDEHP
(a) (b)
0.85 0.90 0.95 1.00 1.05
0
1
2
3
4
5
6
0.84 0.87 0.90 0.93 0.96 0.99 1.02
0.01
0.1
1
10
100 HDEHP
log
Kex
r-1, Å
a.
-23
-22
-21
-20
DTPA
log
Kd
issocD
r-1, Å
actinides
lanthanides
Weav
er,
B.;
Kap
pelm
an
n,
F.A
. J.
In
org
. N
ucl.
Ch
em
. 1968
, 30
, 2
63
-27
2.
b.
Experimental
TALSPEAK CURVE: AN ILLUSTRATION OF A SEE-SAW EFFECT IN SEPARATIONS
4 ACTINIDE AND FISSION PRODUCT PARTITIONING AND TRANSMUTATION, ISBN 978-92-64-99174-3, © OECD 2012
Results and discussion
Figure 2: Distribution of Am(III), Ce(III) and Eu(III) for DTPA-containing TALSPEAK-type liquid-liquid systems
Organic – 0.1 M HDEHP in n-dodecane, aqueous – 0.05 M DTPA, 1.0 M appropriate buffer adjusted to pH under investigation
0.87 0.90 0.93 0.96
-1
0
1
2
3
pH 3
citrate buffer
log
D
r-1, Å
Ce Am Eu Ce Am Eu Ce Am Eu
0.87 0.90 0.93 0.96
r-1, Å
pH 2
dimethyl glycine
buffer
0.87 0.90 0.93 0.96
r-1, Å
pH 1
sulfamate buffer
TALSPEAK CURVE: AN ILLUSTRATION OF A SEE-SAW EFFECT IN SEPARATIONS
ACTINIDE AND FISSION PRODUCT PARTITIONING AND TRANSMUTATION, ISBN 978-92-64-99174-3, © OECD 2012 5
Scheme 2: Structures of the aqueous phosphonic acid complexing agents investigated within TALSPEAK-type actinide/lanthanide separation framework, i.e. diethylenetriamine-
N,N,N’,N”,N”-pentaphosphonic acid, DTPP, and the ethylenediaminetetraphosphonic acid, EDTP
DTPP
EDTPN
N
N P
OOH
OH
P OOH
OH
P
O
OH
OH
P
O
OHOH
P OOH
OH
N
NP
O
OH
OH
PO
OHOH
P
OOH
OH
P
O
OH
OH
TALSPEAK CURVE: AN ILLUSTRATION OF A SEE-SAW EFFECT IN SEPARATIONS
6 ACTINIDE AND FISSION PRODUCT PARTITIONING AND TRANSMUTATION, ISBN 978-92-64-99174-3, © OECD 2012
Figure 3: Distribution of Am(III), Ce(III) and Eu(III) for DTPP-containing TALSPEAK-type liquid-liquid systems
Organic – 0.1 M HDEHP in n-dodecane, aqueous – 0.05 M DTPA, 1.0 M appropriate buffer adjusted to pH under investigation
0.87 0.90 0.93 0.96
-2
-1
0
1
2
pH 3
citrate buffer
log
D
r-1, Å
Ce Am Eu Ce Am Eu Ce Am Eu
0.87 0.90 0.93 0.96
r-1, Å
pH 2
dimethyl glycine
buffer
0.87 0.90 0.93 0.96
r-1, Å
pH 1
sulfamate buffer
TALSPEAK CURVE: AN ILLUSTRATION OF A SEE-SAW EFFECT IN SEPARATIONS
ACTINIDE AND FISSION PRODUCT PARTITIONING AND TRANSMUTATION, ISBN 978-92-64-99174-3, © OECD 2012 7
Figure 4: Distribution of Am(III), Ce(III) and Eu(III) for EDTP-containing TALSPEAK-type liquid-liquid systems
Organic – 0.1 M HDEHP in n-dodecane, aqueous – 0.05 M DTPA, 1.0 M appropriate buffer adjusted to pH under investigation
0.87 0.90 0.93 0.96
-2
-1
0
1
2
pH 3
citrate buffer
log
D
r-1, Å
Ce Am Eu Ce Am Eu Ce Am Eu
0.87 0.90 0.93 0.96
r-1, Å
pH 2
dimethyl glycine
buffer
0.87 0.90 0.93 0.96
r-1, Å
pH 1
sulfamate buffer
TALSPEAK CURVE: AN ILLUSTRATION OF A SEE-SAW EFFECT IN SEPARATIONS
8 ACTINIDE AND FISSION PRODUCT PARTITIONING AND TRANSMUTATION, ISBN 978-92-64-99174-3, © OECD 2012
Figure 5: The comparison of distribution ratios for Am(III), Ce(III) and Eu(III) collected at normal aqueous TALSPEAK conditions (0.05 M DTPA, 1.0 M H
+/Na
+, Lac
–, pH 3.5), where an organic
diluent varies between aliphatic hydrocarbon, n-dodecane, and aliphatic alcohol, 1-dodecanol
0.86 0.88 0.90 0.92 0.94 0.96
-2
-1
0
1
2
n-dodecane
1-dodecanol
log
D
r-1
, Å
Ce Am Eu
Conclusions
TALSPEAK CURVE: AN ILLUSTRATION OF A SEE-SAW EFFECT IN SEPARATIONS
ACTINIDE AND FISSION PRODUCT PARTITIONING AND TRANSMUTATION, ISBN 978-92-64-99174-3, © OECD 2012 9
Acknowledgements
References