You-Shao Wang, Chao-Hong Shen, Jian-Kang Zhu,. Bo-Rong Bao. Institute of Nuclear Research,. Chinese Academy of Sciences, P.O.Box 800-204,. Shanghai ...
J.Radioanal.Nucl.Chem.,Letters 212 (2) 101-106.(1996)
Jointly published by Elsevier Science S. A., Lausanne and Akad(miai Kiad6, Budapest
SOLVENT EXTRACTION OF URANYL(II) ION WITH N,N,N,N-TETRABUTYLSUCCINYLAMIDE FROM NITRIC 'ACID SOLUTION
You-Shao Wang,
Chao-Hong Shen, Bo-Rong Bao
Jian-Kang
Zhu,
Institute of Nuclear Research, Chinese Academy of Sciences, P.O.Box 800-204, Shanghai, China
Received Accepted
24 October 6 November
1995 1995
N,N,N,N-tetrabutylsuccinylamide(TBSA) in a diluent composed of 50% trimethylbenzene(TMB) and 50% kerosene(OX) can extract uranyl(II) ion from nitric acid solution. The results of extraction study suggested the formation of the 1:2:1 uranyl(II) ion, nitrate ion and N,N,N,N-tetrabutylsuccinylamide complex as extracted species. The values of thermodynamic functions have been calculated.
INTRODUCTION Substituted
alkylamides
have been reported in many contain
as extractants for actinides I-3 papers . These compounds
strongly polar C=O groUps.
ity for metal cations 0236-5731/90/US $12.0 Copyright 9 1996 Akad6miai Kiad6, Budapest All rights reserved
Their chelating
abil-
is similar to those of the exI01
WANG et al.: EXTRACTION OF URANYL(II)
tractants
containing
tain no p h o s p h o r u s new solid waste The r a d i o l y t i c as c a r b o x y l i c process.
phosphorus.
atom are important,
because
degradation
acid and amines)
[HNO3],
[UO~+],[TBSA]
potentially
ability
of T B S A
indicate
systematically
for uranyl(II)
that TBSA is good
ion from nitric uranyl(II)
ion.
to the ex-
fuel.
the effects
of
on the e x t r a c t i n g
The e x t r a c t i n g
for the e x t r a c t i o n
acid medium.
(such
excellent
of n u c l e a r
and t e m p e r a t u r e
con-
incinerable.
products
are not h a r m f u l
for the r e p r o c e s s i n g
This paper d i s c u s s e s
which
they do not p r o d u c e
of being c o m p l e t e l y
and h y d r o l y t i c
They are c o n s i d e r e d
tractants
The c o m p o u n d s
Extraction
ion by T B S A and t h e r m o d y n a m i c
data
uranyl(II)
mechanism
of
parameters
are
presented.
EXPERIMENTAL TBSA was purity
synthesized
of the d i s t i l l e d
analysis,.IR purity
phase,
to S t a n l e y
was c h e c k e d
and NMR
was better
contained
ion and HNO 3, was containing
equilibrated
with
shaken
than
Samples
ately after uranyl(II) photometric
phase
amount
a suitable
by elemental
98%.
amount
A typical
of uranyl(II) I ml of organic
acid solution.
of 50% t r i m e t h y l b e n z e n e
Separation.
ion was d e t e r m i n e d
were
The c o n c e n t r a t i o n
102
immediof
by the a r s e n a z o - I I I
ion was calculated.
The
and 50%
analyzed
m e t h o d 5, and then the d i s t r i b u t i o n
of uranyl(II)
ex-
of TBSA which was pre-
nitric
of both phases
The
0.5 ml of the aqueous
for 10 m i n with
a certain
was c o m p o s e d
kerosene.
a certain
et al. 4. The
spectrometry.
p r o c e d u r e was as follows:
which
diluent
product
spectrometry
of the p r o d u c t
traction
phase
according
spectro-
coefficient
WANG et al.: EXTRACTION OF URANYL(II)
,~, 50 O
,-n 3O
I0 7 5
i
I
I
3
I ,i,L 5 7 10
[HN03] I mot. 1-1
Fig.
I. R e l a t i o n s h i p between i~ D U O S + and Ig[HNO 3] at 20 ~ [UO~ +] =5.00xi0 -j molZl -I; [TBSA]=0.5 tool 1-I
RESULTS
AND D I S C U S S I O N
Figure
I shows the effect of the c o n c e n t r a t i o n
on the d i s t r i b u t i o n two phases.
There was a close
distribution
coefficient
concentration
of HNO3.
in the aqueous traction
ions slope
relationship
of uranyl(II)
is about
I-6 mol
ion.
which
of HNO 3
ion in the
between
the
ion and the of HNO 3
1 -I for the ex-
There was c o m p e t i t i v e
b e t w e e n NO 3- and uranyl(II)
a maximum
ion.
is due to c o m p e t i t i o n
and HNO 3 for_ the c o o r d i n a t i o n
The curve of uranyl(II)
sites of TBSA,
the
of ig DUO
is n e a r l y centration ficient
2+ against ig [ HNO 3] w i t h i n 6 mol 1 -I 2 2. Figure 2 i l l u s t r a t e s the effect of the conof uranyl(II)
ion on the d i s t r i b u t i o n
coef-
of uranyl(II)
distribution with
phase
of uranyl(II)
The best c o n c e n t r a t i o n
of the uranyl(II)
extraction shows
coefficient
ion b e t w e e n the two phases, the 2+ c o e f f i c i e n t of UO 2 increases linearly
an increase
in the c o n c e n t r a t i o n 103
of uranyl(II)
ion.
WANG et al.: EXTRACTION OF URANYL(II)
~+~ 30 0
I
I
f
I
3
I
I
5
I
i
7
10
ot,t-' Fig. 2. Relationship between ig Dr~n2~-and ig[UO 2+]at 20 ~ [TBSA]=0~ tool I-I.~2[HNO3]=3.5 mol 1 -I
I0
5 3
I
0.1
Fig. 3 .
I
0.3
t
I
i
I
t
t
0.5 0.7 [TBSA.l,moI-{ -1
Relationship between i~ DUO2+ and Ig[TBSA] at 20 ~ [UO~+]=5.00xl0 -j mo121 -I ; [HN03]=3.5 mol 1 -I
Figure 3 indicates the effect of the concentration of TBSA on the extraction of uranyl(II) ion, the ig DUO 2+ 2 va 1 ues increase linearly with increasing concentration of TBSA, with a slope of unity. This results show the binding ratio of TBSA with uranyl(II) 104
ion to be 1:1.
WANGeta].: EXTRACTIONOF URANYL(II) ~
10
o s
5
3
3.0
3.2
3,4
y1, x10-3 Fig.
! [uo2+] = 4. Relationship between ig DUO2+ and ~ 1 [HN03]= 5.00xi0 -3 tool i -1 ; [TBSA]=0,"5 mol 3.5 tool 1 -I
Figure
4 illustrates
the effect of temperature
on the
distribution coefficient of uranyl(II) ion. Thel ig DUO22 + values increase linearly with the increase of ~ . Thus the extraction
of uranyl(II)
ion from the aqueous to the
organic phase is an exothermic of UO22+
extraction
process, and the enthalpy is -18.63 kJ mol -I "
In these extraction
studies,
TBSA in the organic phase
was present in a large excess compared with uranyl(II) ion in the aqueous phase.
The results in Figs 1 and 3
suggest that the 1:2:1 complex of uranyl(II) and TBSA was extracted extraction
into the organic phase.
reaction of the present
pressed as Eq.
ion, NO 3Thus, the
system can be ex-
(I).
U022+ (aq) + 2N03 (aq) + TBSA(org) = U02 (NO3)2"TBSA(org)
Then,
the extraction
constant
Kex = [UO2 (NO3)2 "TBSA]o--+ r [UO~ ~
105
(I)
(Kex) be defined as ] aq [-IrNO-~-2 3j aq ~ iTBSA~-Ijorg
(2)
WANG et al.: EXTRACTION OF URANYL(II)
and Eq.
(2) can be r e a r r a n g e d as follows:
Kex = Du[NO~ ]-2 [TBSA]-I
(3)
ig D u = ig Kex + 2 ig[NO3Jaq + ig[TBSA]org
(4)
aq
org
or
A c c o r d i n g to Eq. (4) (for the [HNO3], [TBSA] and U 022+ ] to c a l c u l a t e Kex see Fig. 3). The value for Kex(50%TMB+50%OK)
was e v a l u a t e d to be I .22+-0.06.
The suggested
structure of the I : 2 :I complex w h i c h
2+ , NO 3 and TBSA can be e x p r e s s e d as folc o n s i s t e d of UO 2 lows 6 : 0~
N."E~O~ 0i A~O""~.N ~ ' 0
ti
C
o
II
C
X = N(C4H9) 2 REFERENCES I. C. Musikas, 1211.
Sep.
Sci. Technol.,
2. G.M. Nair, D.R. Prabhu, Ion Exch., 11(5) (1993) 3. C. Cuillerdier, Technol., 26(9) 4. R.S. Stanley, rations, Vol, 277.
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G.R. M a h a j a n et al. Sol. Extr. 813.
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K. Wolf, O r g a n i c F u n c t i o n a l Group PrepaI, A c a d e m i c Press, New York (1968) P.
5. Ma Hengli, et al., A t o m i c E n e r g y Science and. T e c h n o l o g y (in Chinese), 6 (1964) 748. 6. L. Nigond, C. Musikas, 12(2) (I 994) 297.
eta!.,
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Ion Exch.,