Journal of Nuclear and Radiochemical Sciences, Vol. 6, No. 2, pp. 119-126, 2005

ArticlesExtraction and Separation of Uranium (VI) and Thorium (IV) Using Tri-n-dodecylamine
Impregnated Resins
E. Metwally,* A. Sh. Saleh, and H. A. El-Naggar
Nuclear Chemistry Department, Radioisotopes Production and Radiation Sources Division,
Hot Laboratories Center, Atomic Energy Authority, P.O. Box 13759, Cairo, Egypt
Received: October 18, 2004; In Final Form: January 15, 2005
Extraction of U(VI) and Th(IV) from chloride and nitrate solutions with tri-n-dodecylamine impregnated on
Amberlite XAD4, was investigated. The distribution of U(VI) and Th(IV) was studied at different concentrationsof acid, salting-out agent, extractant, aqueous metal ion and other parameters. Absorption spectral studies havebeen investigated for uranium species in both aqueous HCl solution and the resin phase. From these studies, it issuggested that the tetrachloro complex of U(VI) is formed in the extraction of uranium (VI) from hydrochloric
acid solutions by TDA impregnated resin. Stripping of the extracted U(VI) and Th(IV) was assayed with HCl and
HNO3. Finally, the separation of uranium from thorium and fission products in HCl media was achieved.

1. INTRODUCTION

2. EXPERIMENTAL

There is a growing need for uranium and thorium, the mainradioactive elements, for nuclear fuel production. Disposal ofindustrial waste effluents containing uranium and thorium has
serious hazard impacts on the environment. Therefore,
recovery of these two elements from aqueous waste solutions
is preferable for economical and ecological reasons.
Solvent impregnated resin (SIR) is a good alternative tosolvent extraction and ion exchange techniques for metal separation and recovery. They combine the advantages of solvent
extraction systems such as fast mass transfer rates, high distribution and selectivity factors, with the advantages of solid ionexchange technology such as simplicity of equipment andoperation and applicability for processing very dilute solutions.1
For these reasons, SIRs have been widely used in metal recovery
and separation in the nuclear industry,2−4 hydrometallurgicalapplications for the separation of rare earth elements,5−7 platinum group metals,8, 9 gold,10−12 and base metals.13−16 SIRs are
suitable also for preconcentration and separation of trace metal
ions for analytical purposes.17−21
Solvent extraction with high molecular weight amines provides
a useful method for recovery of actinides.22, 23 Preparation of a
new type of metal ion selective resin based on phosphoric acidfunctionality and its application on the separation of Mo and V
ions have been reported, where the metal ion selective resin was
prepared by immobilizing D2EHPA onto the surface of porous
Amberlite XAD4 resin.24 The recovery of Pd, Pt, and Rh frombatches of industrial metal refinery effluents containing large
amounts of Ni, Cu, and Fe ions and relatively small amounts ofthe expensive Pt, Pd, and Rh ions has been investigated withsilica-based poly amine anion exchangers.25 However, thestudies on recovery and separation of actinides with amine
impregnated resins18, 20 are few. The present work aimed toinvestigate the extraction of uranium (VI) and thorium (IV)from chloride and nitrate media with tri-n-dodecylamine (TDA)
impregnated resin, to throw light on the extraction mechanism
and to compare it with that in solvent extraction systems. The
separation of uranium from thorium and fission products with
the TDA impregnated resin was studied as well.

Reagents: Reagent grade TDA (> 95% purity, Merck) wasused as extractant without further purification. Amberlite
XAD4 resin (Rohm and Hass) was used as a macroporous
polymeric support. It is made of styrene-divinylbenzene
copolymer with a specific surface area of 750 m2/g, an averagepore diameter of 40 Å, and a particle size of 20 – 50 mesh. The
resin was washed with distilled water and acetone several
times in turn, and dried at 50˚C. Stock solutions of U(VI) andTh(IV) (~10−3 M) were prepared by dissolving UO2Cl2 ·2H2O
and Th (NO3)4 · 4H2O (Prolabo) in distilled water, respectively.
Concentrated HCl (1 – 2 mL) was added to 100 mL solutionsof U(VI) and Th(IV) to suppress hydrolysis. 152,154Eu, 51Cr,
60
Co, 65Zn, and 134Cs were obtained by neutron irradiation of
appropriate target materials in the ERR-1 reactor in Egypt. All
chemicals used were of analytical grade.
Preparation of impregnated resin: Impregnated resins
were prepared using a dry impregnation method.1 An appropriate volume of 0.2 M TDA solution in n-hexane was mixed
with a weighted amount of the resin for 1 hour. The diluent
was then evaporated at 50˚C for 24 hours. The concentrationof TDA in the prepared impregnated resin was determinedfrom the amount of HCl sorbed by shaking the impregnatedresin with 0.1 M HCl, and is given as moles of TDA per Kg of
dry impregnated resin.
Extraction procedure: All extraction experiments wereconducted batch wise at room temperature (25 ± 2˚C). Samples
of 0.05 g of impregnated resin were shaken vigorously with 5
mL of aqueous solutions containing U(VI) or Th(IV) (~10−4 M)
for 24 hours, unless otherwise stated. 152,154Eu, 51Cr, 60Co, 65Zn,
and 134Cs were used in trace concentrations. The distribution
ratio (D) and the uptake percent of metals were calculated asfollows:*Corresponding author. E-mail: emetwally3@yahoo.com. FAX:
+202-4620-806.

D=[M]i – [M]e V[M]i – [M]e×
& Uptake % =× 100,m[M]e[M]iwhere [M]i and [M]e are the initial and the equilibrium concentrations of metal ions in the aqueous phase, respectively, V isvolume of the aqueous phase, and m is weight of dry impregnated resin. The uranium and thorium concentrations were
determined spectrophotometrically using a spectrophotometer(Shimadzu UV-120-02) with arsenazo III.26 Gamma emitter© 2005 The Japan Society of Nuclear and Radiochemical Sciences
Published on Web 11/07/2005

Metwally

120 J. Nucl. Radiochem. Sci., Vol. 6, No. 2, 2005
radioisotopes were controlled using hyper pure germanium
detector connected to a multichannel analyzer (Canberra Genie
2000). The extracted uranium amine complexes were eluted
from metal-loaded impregnated resins by shaking withbenzene for 24 hours. The absorption spectra of these benzene
solutions and the corresponding aqueous phases were obtainedby a spectrophotometer (Shimadzu UV-160 A).
3. RESULTS AND DISCUSSION
3.1. Extraction of uranium from chloride media. The
effect of contact time on sorption of U(VI) from 6 M HCl solution with TDA-impregnated resin is shown in Figure 1. The
uranium uptake percent increases with increasing contact time
till equilibrium is reached after 24 hours. The extraction of
10−4 M UO22+ solution with TDA-impregnated resin was examined at different HCl concentrations. The results indicate thatUO2Cl2 + mR3NH+Cl−(r) →← (R3NH)mUO2Cl2+m (r) ,

100

80

Uptake %U(VI) extraction increases with increasing acidity and becomes
quantitative at 7 M HCl. The data are shown in Figure 2. These
results are in agreement with those obtained for the solvent
extraction of U(VI) from HCl solution with high molecularweight amines dissolved in organic solvents.27−31 The results
for the extraction of U(VI) from solutions containing 0.1 M
HCl and lithium chloride at various concentrations are alsopresented in Figure 2. As LiCl concentration increases, theuptake percent of U(VI) increases. This probably implies thatthe controlling factor for the extraction process is the chloride
ion concentration. Thus, it may be assumed that the increasein U(VI) extraction arises from the effect of chloride ion in the
aqueous phase or from the formation of an extractable uranylchloro complex. Hence, it is possible to describe the present
extraction reaction in the same way as reported for the solvent
extraction of uranium in U(VI)-HCl-R3N systems.27, 28

60

40

20

[TDA] r
0.96
0.48

0
0

10

20

30

40

50

60

70

80

Time /hFigure 1. Effect of contact time on sorption of U(VI) from 6 M HCl
with TDA-impregnated resin; [TDA](r) : in the unit of mol/kg.

(1)

where the subscript (r) denotes the resin phase.
The effect of hydrochloric acid concentration on sorption of
U(VI) was studied at constant chloride ion concentration. The
total chloride ion concentration was kept constant using
lithium chloride. As shown in Figure 3, at low aqueous acidities, the uranium distribution ratio increases with increasing
HCl concentration. At high aqueous acidities, the distribution
ratio becomes approximately constant. This behavior has notbeen reported before for the extraction of actinides by amines.
A possible explanation for this behavior may be as follows: at
low aqueous acidities, the replacement of hydrogen ion bylithium ion results in a decrease in the distribution ratio
because Li+ ion has a lower hydration affinity than H+ ion andconsequently Li+ ion has a lower salting-out effect than H+ ion.
At high aqueous acidities, the extraction of excess HCl which
is a little from aqueous acid concentrations below 2 M 23
becomes more pronounced. The competition between excess
HCl and uranium for association with amine results in adecrease of the uranium distribution ratio. This decrease iscompensated by the higher effect of the hydrogen ion.
The uranium distribution ratio, determined as a function ofamine concentration in the resin phase, is presented in Figure

100

1000

Distribution ratio /L kg -1

Uptake %

80

60

40

100

20

-

[Cl ]
10M
4M
0
0

2

4

6

8

10

Total chloride ion concentration /M

Figure 2. Extraction of U(VI) from HCl and LiCl solutions by TDAimpregnated resin ( : in presence of HCl only, ¡: in presence of 0.1
M HCl and LiCl), [TDA](r) = 0.96 mol/kg-sorbent.

0.1

1

10

[HCl] /M

Figure 3. Effect of HCl concentration on sorption of U(VI) at
constant chloride ion concentration; [TDA](r) = 1.05 mol/kg-sorbent.

Extraction and Separation of Uranium (VI) and Thorium (IV)4, where uranium distribution ratio increases slightly withamine concentration then it decreases at high amine concentrations. Blocking of resin pores by amine molecules andextracted metal complexes may be the reason for such
behavior.8, 32 The uranium concentration of the resin phase isdetermined as a function of initial aqueous uranium concentration at 7 M HCl. The data shown in Figure 5 represents a
typical Langmiur isotherm. The U(VI) concentration of theresin phase approaches a limiting value of ~0.04 mol/kg.
According to eq 1 the uranium to amine loading ratio wasDistribution ratio /L kg

-1

1000

100

J. Nucl. Radiochem. Sci., Vol. 6, No. 2, 2005 121
expected to amount of 1/m. However, the ratio was found to
be much smaller than any reasonable value for 1/m. Thissuggests that some of the amine molecules within the sorbent
are unavailable and do not participate in the sorption reaction
owing to steric hinderance or an occlusion.8, 32
Adsorption Spectral Studies: The absorption spectra ofaqueous uranyl chloride solutions (0.015 M) containinghydrochloric acid at various concentration are presented in
Figure 6a. The corresponding spectra of uranium species
eluted from impregnated resin (preloaded with uranium) using
benzene are presented in Figure 6b. For the spectra of aqueous
uranyl chloride solutions, the following results were observed:
In 1 M HCl, a band center at 415 nm is exhibited due to theuranyl ion UO22+,33 while in 5 M HCl, this absorption shifts tolonger wavelength due to the formation of the species UO2Cl+
and UO2Cl2 33 and is accompanied by the characteristic absorption peaks at 402, 428, 441, 460, 467, and 492 nm, which probably arise from the presence of the complex ion UO2Cl42−.34, 35
For solutions up to 9 M HCl, these peaks show a progressive
increase in intensity, which indicates that UO2Cl42- complex
becomes more predominant. In contrast, the spectra of theorganic solutions show largely the adsorption peaks characteristic to the UO2Cl42− complex, even though the spectrum of theaqueous solution at low HCl concentration does not indicate
the presence of UO2Cl42− complex ion. This indicates that theextracted species is the six-coordinated uranium complex ion
UO 2 Cl 4 2− and the value of m in eq 1 equals 2. Hence, theextraction reaction may be written as follows:
UO2Cl2 + 2 R3NH+Cl−(r) →← (R3NH)2 UO2Cl4 (r)4M HCl2M HCl
10
0.4

0.5

0.6

(2)

3.2. Extraction of uranium from nitrate media. Extractionof U(VI) from aqueous solutions containing various concentrations of nitric acid with TDA-impregnated resin is shown in

0.7 0.8 0.9 1[TDA] r /mol kg-1

Figure 4. Effect of TDA concentration on extraction of U(VI) fromHCl solutions.
0.05

+2

[UO2 ] r /mol/kg-sorbent

0.04

Figure 6a. Absorption spectra of aqueous uranyl chloride solutions(0.015 M) in the presence of HCL acid at different concentrations;numerals on curves are initial aqueous HCl concentrations (M).

0.03

0.02

0.01

0.00
0.0000[TDA] r1.05
1.18

0.00050.0010+2[UO2 ] initial /M

Figure 5. Effect of initial aqueous UO22− concentration on amount of
UO22− sorbed from HCl solution by TDA-impregnated resin; [HCl] =7 M, [TDA](r) : in the unit of mol/kg-sorbent.

Figure 6b. Absorption spectra of benzene solutions of uranium
species extracted at different HCl concentrations; numerals on curves
are initial aqueous HCl concentrations (M), [TDA](r) = 1.05 mol/kg.

Metwally

122 J. Nucl. Radiochem. Sci., Vol. 6, No. 2, 2005
Figure 7. The uptake percent of uranium increases withincreasing initial aqueous HNO3 concentration, reaches a maximum at approximately 5 M HNO3, and then decreases. The
uptake percent does not exceed 20% in the whole range ofacidity studied. Generally, the extraction reaction could possibly be described as follows:
UO2 (NO3)2 + m R3NH+ NO3−(r)→← (R3NH)m UO2 (NO3)2+m (r)(3)

Therefore, the nitric acid dependency may be explained as100

80

Uptake %60

follows: at low aqeous acidities, the increase in the uptake
percent arises from the effect of nitrate ion or the formation of
extractable uranium-nitrato complex. Where, at high aqueous
acidities, the decrease in the uptake percent is attributed tocompetition between nitric acid and uranium species for the
association with the amine or to the formation of less readily
extractable complexes. Sato 36 explained similarly the aciddependency of uranium (VI) extraction from nitric acid solutions by tri-n-octylamine dissolved in benzene. So, one should
expect no decrease of the uranium uptake percent when plottedagainst the nitrate ion concentration at constant (low) aqueous
acidities. Actually, this behavior is verified when lithium
nitrate is the source of nitrate ions, as shown in Figure 7, where
the uptake percent increases continueously with increasing
nitrate ion concentration.
Figure 8 represents the extraction of U(VI) as a function of
initial aqueous nitric acid concentration, while the total nitrate
ion concentration was kept constant using lithium nitrate. The
uranium distribution ratio decreases with increasing nitric acidconcentration. This behavior confirms the assumption thatnitric acid competes with uranium for association with theamine through the reaction:23+−
R3NH+ NO3−(r) + HNO3 →← R3NH NO3 · HNO3 (r)

40

20

0
0

2

4

6

8

10

12

Total nitrate ion concentration /M

Figure 7. Extraction of U(VI) from HNO 3 and LiNO3 solutions by
TDA-impregnated resin ( : in presence of 0.2 M HNO3 and LiNO3,¡: in presence of HNO3 only), [TDA](r) = 0.96 mol/kg-sorbent.

(4)

3.3. Elution of uranium. Elution of uranium from metal
preloaded impregnated resin with HCl and HNO3 acids ofvarious concentrations is presented in Figure 9. The maximum
elution percent of U (VI) was attained using dilute acids,
which is in agreement with results obtained by Felinto et al.37
The hydrochloric and nitric acid dependencies of elution
percent have reversible shapes to that of acid dependencies of
uptake percent shown in Figures 2 and 7. It means that theextraction reactions of uranium (VI) from hydrochloric andnitric acids eqs 2 and 3 are reversible.
Two successive extraction-elution cycles were carried out
on the system U(VI)-HCl-TDA/XAD4. The data are listed inTable 1. Uptake percent of the second extraction process is
10% less than that at the first extraction process. This decrease
may be attributed to leakage of some amine molecules from theresin. More investigations are required to precisely describe80-[NO3 ]

HNO3
HCl

70

10M
4M

60

100

Elution %Distribution ratio /L kg

-1

50

40

30

20

10
10

0
0

0.1

1

10

[HNO3 ] /M

Figure 8. Effect of HNO 3 concentration on sorption of U(VI) at
constant nitrate ion concentration; [TDA](r) = 1.05 mol/kg-sorbent.

2

4

6

8

10

Acid concentration /M

Figure 9. Effect of HCl or HNO3 concentration on elution of U(VI)loaded on TDA-impregnated resin; [U](r,initial) = 0.008 mol/kg, m = 0.05
g, V = 5 mL, [TDA](r) = 0.96 mol/kg.

J. Nucl. Radiochem. Sci., Vol. 6, No. 2, 2005 123

Extraction and Separation of Uranium (VI) and Thorium (IV)

Extraction processes[U] initial = 10−4 M[HCl] = 7 M

Uptake %Elution processes Elution %[HCl] = 0.01 M

First extraction

100

First elution

73

Second extraction

90

Second elution

70[TDA] (r) = 0.96 mol/kg, m = 0.05 g, V = 5 mL.

this behavior and its effect on the stability of the amine impregnated resins.
3.4. Extraction of thorium from chloride media. The extraction of Th(IV), 10−4 M, from hydrochloric acid solutions with
TDA-impregnated resin was experimented. The uptake percentof thorium is negligible all over the studied range of HCl concentration, as observed in the solvent extraction with high molecularweight amines.38, 39 This behavior was reasoned, since thorium(IV) does not form anionic complexes with the chloride ion.
3.5. Extraction of thorium from nitrate media. Based on
preliminary experiments of nitrate ion concentration dependency, effect of contact time on sorption of ~10−4 M Th(IV),from nitrate media was studied at 6 M initial nitrate ion
concentration. As Figure 10 indicates, equilibrium is attained
after 24 hours. Therefore, a 24 hours extraction time waschosen for all the subsequent experiments.
Figure 11 represents the extraction of Th(IV) from aqueous
solutions containing various concentrations of nitric acid. The
uptake percent of thorium increases with increasing nitric acidconcentration, reaching a maximum of ~25% at approximately
6 M HNO3 and then decreases. This behavior was observed forthe extraction of Th(IV) with high molecular weight amines.39, 40
and could be interpreted as follows: at low aqueous acidities theincrease in the uptake percent arises from the effect of nitrate
ion in the aqueous phase or the formation of extractable
thorium nitrate complexes; while at high aqueous acidities thedecrease in the uptake percent is attributed either to competition between nitric acid and thorium complexes for association
with amine or to the formation of less readily extractable
100

thorium complexes. The results of the extraction of thoriumfrom aqueous solutions containing 0.2 M nitric acid and lithium
nitrate at various concentrations are shown in Figure 11.
Replacement of nitric acid in the aqueous phase by lithium
nitrate (except the amount of acid needed for the amine salt
formation) checks the above mentioned decrease in the thorium
percentage uptake at high aqueous acidities. The reason for thischeck may be the removal of nitric acid which competes withthorium complexes for association with the amine. On theother hand, when a part of nitric acid was replaced by lithium
nitrate, thorium distribution ratio increased considerably, as
shown in Figure 12. Thus at constant nitrate ion and TDA
100

80

60

Uptake %TABLE 1: Two Successive Extraction Elution Cycles ofUranyl Chloride from TDA-Impregnated Resin

40

20

0
2

4

6

8

10

Total nitrate ion concentration /M

Figure 11. Extraction of Th(IV) from HNO3 and LiNO3 solutions by
TDA-impregnated resin ( : in presence of 0.2 M HNO3 and LiNO3,¡: in presence of HNO3 only); [TDA](r) = 0.96 mol/kg.

-[NO3 ]
4M
3M

80

-1

100

Uptake %Distribution ratio /L kg

60

40

20

[TDA]r
0.48
0.96

0
0

10

20

30

40

50

60

70

80

Time /hFigure 10. Effect of contact time on sorption of Th(IV) from 6 M
nitrate solution (0.2 M HNO3 + 5.8 M LiNO3) with TDA-impregnatedresin; [TDA](r): in the unit of mol/kg.

10
0.1

1

[HNO3] /M

Figure 12. Effect of HNO3 concentration on distribution of Th(IV) at
constant nitrate ion concentration; [TDA](r) = 0.96 mol/kg.

Metwally

124 J. Nucl. Radiochem. Sci., Vol. 6, No. 2, 2005
concentrations, the distribution ratio decreases with increasing
acidity. This phenomenon is also probably associated with theformation of the acid species R3NHNO3 in the resin phase. A
similar behavior was observed for solvent extraction of cerium(III) by TDA.41
The amine dependency of thorium (IV) extraction wasstudied at constant nitric acid and nitrate ion concentrations.
As shown in Figure 13, thorium distribution ratio, D, increases
slightly with increasing TDA concentration from 0.48 to 0.96
mol/kg followed by a steep increases till extraction of thorium
becomes nearly qualitative. The amine dependency could notproperly describe the present extraction equilibrium, probably

Distribution ratio /L kg

-1

1000

-

[NO3 ]

100

5.5M
4.0M
0.4

0.5

0.6

0.7

0.8 0.9[TDA] r /mol kg

1-1

Figure 13. Effect of TDA concentration on extraction of Th(IV) from
nitrate media (0.2 M HNO3 + LiNO3).

due to complicating factors originating from blocking of resin
pores8, 32 by amine molecules, amine aggregates and amine
metal complex mixed associates which may be formed in theresin phase.
Figure 14 represents thorium concentration of the resin
phase as a function of initial aqueous thorium concentration.
Sorption behavior represents a typical Langmiur isotherm.
The amounts of Th (IV) sorbed by the resin increase withincreasing aqueous thorium concentration and approaches
limiting values of 0.05 and 0.07 mol/kg with sorbents of 0.96
and 1.32 mol/kg, respectively. The thorium to amine loading
ratio is too small to reasonably indicate their stoichiometricratio in the extracted species. The reason for this complication
may be the existence of unavailable TDA molecules within thesorbent, which do not partricipate in the sorption reaction due
to steric hindrance or occlusion.8, 32
3.6. Elution of thorium (IV). Figure 15 shows the effect of
initial aqueous concentrations of HCl and HNO3 on the percentof thorium eluted from TDA-impregnated resin preloaded withTh(IV). As would be expected, hydrochloric acid is much
more efficient than nitric acid for thorium elution. The
maximum elution percent attained with nitric acid was 66%
using 0.01 M HNO3. Approximately the same elution percent
was attained, when distilled water was used as an eluent.
Quantitative recovery of thorium is possible only with dilute
HCl solution.
The trend of nitric acid dependency of thorium elution,
shown in Figure 15, is nearly the reverse of that of thorium
extraction. (See Figure 11 which indicates that thorium extraction is a reversible process.) The successive extraction elution
cycles were performed to study the regeneration of the TDAimpregnated resin after being loaded with thorium. The conditions and results obtained are given in Table 2. Results
indicate that the extraction process is reversible and TDAimpregnated resin can be regenerated and reused efficiently.
3.7. General application to metal separation. The results
obtained in the single metal experiments indicate that theextractabilities of uranium (VI) and thorium (IV) from nitricacid media are similarly low. On the other hand, U(VI) could
be extracted quantitatively from HCl acid of concentration > 6
M, whereas Th(IV) extraction is negligible in the whole range

0.08

HNO3
HCl

100

90

Elution %+4[Th ] r /mol kg

-1

0.06

0.04

80

70

0.02

[TDA] r

60

1.32
0.96
0.00
0.00000.00020.00040.00060.00080.0010+4[Th ] initial /M

Figure 14. Effect of initial aqueous Th4+ concentration on amount of
Th4+ sorbed from 0.2 M HNO3 + 5.8 M LiNO3 solution with TDAimpregnated resin; [TDA](r): in the unit of mol/kg.

50
0

1

2

3

4

5

6

Acid concentration /M

Figure 15. Effect of HCl or HNO3 concentration on elution of Th(IV)loaded on TDA-impregnated resin; [Th4+](r,initial) = 5 ×10−3 mol/kg, m =0.05 g, V = 5 mL, [TDA](r) = 0.96 mol/kg.

J. Nucl. Radiochem. Sci., Vol. 6, No. 2, 2005 125

Extraction and Separation of Uranium (VI) and Thorium (IV)TABLE 2: Successive Extraction-Elution Cycles of Thorium(IV) Nitrate on TDA-Impregnated Resin
Extraction processes[Th] initial = 10−4 M[HNO3] = 0.2 M[LiNO3] = 5.8 M

Uptake %First extraction

94

Second extraction

Elution processes Elution %using distilled
waterFirst elution

95

U(VI), Eu(III), Cr(III), Co(II), Zn(II), and Cs(I)In 4M HCl + TDA-impregnated resin

66

Second elution

Resin Phase
U(VI) and Zn(II)Aqueous phase
Eu(III), Cr(III), Co(II), and Cs(I)73[TDA] (r) = 0.96 mol/kg, m = 0.05 g, V = 5 mL.

studied of HCl concentration. This latter observation suggests
the possibility of separating uranium and thorium fromhydrochloric acid medium by TDA-impregnated resin.
Therefore, solution mixture of ~10−4 M initial concentration ofboth U(VI) and Th(IV) cations were extracted with 0.96
mol/kg TDA-impregnated resin from HCl solution of various
concentrations. Results obtained are shown in Table 3 whichindicates that the two cations can be well separated from eachother, especially at high HCl concentration where the uranium
uptake percent is quantitative and thorium uptake is generally
zero.
Available data are sufficient to suggest that separation ofactinides and fission products can be at least as good in
HCl – tri-alkyl amine system as in Purex.42 Therefore, the HClimpregnated resin system was investigated for separation of
uranium from some fission products and some related elements.
TABLE 3: Separation of U(VI) and Th(IV) from HCl
Solutions Using TDA-Impregnated Resin[HCl], M

Uptake % of U(VI)Uptake % of Th(IV)

2
4
6
8
10

34
78
94
99
100

1.6
0.5
0.0
0.0
0.0

[TDA] (r) = 0.96 mol/kg, m = 0.05 g, V = 5 mL.
100

Stripping with
0.1M HCl

Adjustment to 8–9M HCl
Then shaking with TDAimpregnated resin
Aqueous phase
U(VI)Resin Phase
Zn(II)

Aqueous phase
Eu(III), Cr(III), and Cs(I)Resin phase
Co(II)
Stripping with
0.1M HCl
Aqueous phase
Co(II)

TDA-impregnated resin

Figure 17. Flowsheet diagram for separation of U(VI), Eu(III),
Cr(III), Co(II), Zn(II), and Cs(I).

A mixture solution of ~10−4 M U(VI) and tracer Cs(I), Co(II),Zn(II), Cr(III), and Eu(III) ions was extracted by 0.1 g of 0.96
mol/kg TDA-impregnated resin at various HCl acid concentrations. The results are shown in Figure 16. The extraction of
the elements is approximately close to that predicted fromknown anionic chlorocomplexing studies.43 The variations in
the uptake percent of the investigated elements suggest several
alternatives for their separation as groups and from each other.
For example, uranium (VI) can be separated from Cs(I),
Co(II), Cr(III), and Eu(III) by sorption onto TDA-impregnatedresin at 4 M HCl and from Zn(II) by stripping into 1 M HCl.
Also, Co(II) and Zn(II) can be well separated from each otherat 1 – 4 M HCl. While, Zn(II) is almost quantitatively
extracted by the TDA-impregnated resin, where Co(II) remains
almost completely in the residual bulk solution. Figure 17
represents a flowsheet diagram for separation of U(VI),
Eu(III), Cr(III), Co(II), Zn(II), and Cs(I). To be concluded thatsolvent extraction impregnated resin as a recent techniquepromises a wide applicability for separation and removal ofdifferent trace elements. Where U(VI) and Th(IV) aresuccessfully extracted with great extent using tri-n-dodecylamine impregnated resin from aqueous media.

80

REFERENCES

Uptake %

60

40

U(VI)
Eu(III)Cr(III)
Zn(II)
Co(II)
Cs(I)

20

0
0

2

4

6

8

10

[HCl] /M

Figure 16. Sorption of U(VI), Eu(III), Cr(III), Zn(II), Co(II), andCs(I) from HCl solutions by TDA-impregnated resin, [TDA](r) = 0.96
mol/kg.

(1) A. Warshawsky, Ion Exchange and Solvent Extraction 8,
ed. J. A. Marinsky and Y. Marcus, Marcel Dekker, NewYork (1981), p229.
(2) W. Faubel, New Separation Chemistry Techniques forRadioactive Waste and Other Specific Applications, ed. L.
Cecille, M. Casarci, and L. Pietrelli, Elsevier, Amsterdam(1991), p73.
(3) P. K. Mohapatra, S. Sriram, V. K. Manchanda, and L. P.
Badheka, Sep. Sci. Technol. 35, 39 (2000).
(4) M. Yamaura and H. T. Matsuda, J. Radioanal. Nucl. Chem.
224, 83 (1997).
(5) D. Muraviev, Chimica Scripta, 29, 9 (1989).
(6) J. Shibata and S. Matsumoto, Program and Abstracts of
the International Rare Earths Conference, Rare Earths’98,
WA, Australia (1998), p67.
(7) Z. Wang, G. Ma, and D. Li, Solvent Extr. Ion Exch. 16,
813 (1998).
(8) S. Akita, K. Hirano, Y. Ohashi, and H. Takeuchi, Solvent
Extr. Ion Exch. 11, 797 (1993).
(9) M. Rovira, J. L. Cortina, J. Arnaldos, and A. M. Sastre,
Solvent Extr. Ion Exch. 16, 1279 (1998).

126 J. Nucl. Radiochem. Sci., Vol. 6, No. 2, 2005(10) I. Villaescusa, M. Aguilar, J.de Pablo, M. Valiente, and V.
Salvado, Process Metallurgy (Solvent extraction 1990,
Proceedings of International Solvent Extraction Conference),
T. Sekine, Elsevier, Amsterdam (1992), 7A, p171.
(11) I. Villaescusa, N. Miralles, J. de Pablo, V.Salvado, and A.
Sastre, Solvent Extr. Ion Exch. 11, 613 (1993).
(12) I. Villaescusa, V. Salvado, and J. de Pablo, React. Polym.
32, 125 (1997).
(13) J. L. Cortina, N. Miralles, A. M. Sastre, M. Aguilar, A.
Profumo, and M. Pesavento, React. Polym. 18, 67 (1992).
(14) J. L. Cortina, N. Miralles, A. M. Sastre, M. Aguilar, A.
Profumo, and M. Pesavento, React. Polym. 21, 89 (1993).
(15) J. L. Cortina, N. Miralles, A. M. Sastre, M. Aguilar, A.
Profumo, and M. Pesavento, React. Polym. 21, 103 (1993).
(16) J. L. Cortina, N. Miralles, M. Aguilar, and A. M. Sastre,
Hydrometallurgy 36, 131 (1994).
(17) E. P. Horwitz, R. Chiarizia, M. L. Dietz, H. Diamond, andD. M. Nelson, Anal. Chim. Acta 281, 361 (1993).
(18) E. P. Horwitz, M. L. Dietz, R. Chiarizia, H. Diamond, S.
L. Maxwell, and M. R. Nelson, Anal. Chim. Acta 310, 63(1995).
(19) Y. Wakui, S. A. Ndiaye, H. Matsunaga, T. Yokoyama,
and K. Akiba, Anal. Sci. 14, 299 (1998).
(20) Zhang-Yuqin, Uranium Mining and Metallurgy 18, 65(1999).
(21) C. H. Lee, K. S. Choi, J. S. Kim, K. C. Choi, K. Y. Jee,and W. H. Kim, J. Korean Chem. Soc. 45, 304 (2001).
(22) C. F. Coleman, Atomic Energy Rev. 2, 3 (1964).
(23) Y. Marcus and A. S. Kerte, Ion Exchange and Solvent
Extraction of Metal Complexes, Wiley-Interscience, New
York, 1969.
(24) J.-H. Chen, Y.-Y. Kao, and C.-H. Lin, Separation Scienceand Technology 38, 3827 (2003).
(25) J. Kramer, W. L. Driessen, K. R. Koch, and J. Reedijk,

Metwally
Separation Science and Technology 39, 63 (2004).
(26) Z.Marczenko, Spectrophotometric Determination of
Elements, Ellis Horwood, Chichester, 1976.
(27) T. Sato, Anal. Chim. Acta 45, 71 (1969).
(28) T. Sato, J. Inorg. Nucl. Chem. 34, 3835 (1972).
(29) T. Sato, T. Nakamura, and T. Fujimatsu, Solvent Extr. Ion
Exch. 1, 709 (1983).
(30) N. Sezginer, Turkish J. Nucl. Sci. Turkey 11, 65 (1984).
(31) P. Behera, R. Ishra, and V. Chakravortty, Radiochim. Acta
62, 153 (1993).
(32) S. Akita and H.Takeuchi, J. Chem. Eng. Jp. 23, 439 (1990).
(33) J. J. Katz and G. T. Seaborg, The Chemistry of the Actinide
Elements, Methuen, London (1957), p174.
(34) E. Rabinowitch and R. L. Belford, Spectroscopy andPhotochemistry of Uranyl Compounds, Pergamon Press,
Oxford (1964), p112.
(35) W. E. Keder, J. Inorg. Nucl. Chem. 24, 561 (1962).
(36) T. Sato, J. Inorg. Nucl. Chem. 26, 1295 (1964).
(37) M. C. F. C. Felinto, T. A. Kuada, M. Yamaura, H. T.
Matsuda, and B. F. Araujo, Proceedings of the 5th General
Congress on Nuclear Eergy, Rio de Janeiro RJ, Brazil, 3,(1994), p781.
(38) F. L. Moore, Anal. Chem. 30, 908 (1958).
(39) N. Sezginer, J. Less-Common Metals 122, 343 (1986).
(40) W. E. Keder, J. C. Sheppard, and A. S. Wilson, J. Inorg.
Nucl. Chem. 12, 327 (1960).
(41) A. Alian and N. Souka, Zeit. Anorg. Allge. Chem. 336,
306 (1965).
(42) J. C. Mailen and J. T. Bell, Proceedings of the 4th Symposium
on Separation Science and Technology for energy Applications, Knoxville, TN, USA (1985).
(43) K. A. Kraus and F. Nelson, Proceedings of the International
Conference on the Peaceful Uses of Atomic Energy, Geneva,
7, 1955, United Nations (1956), p113.