Studies on Separation of Actinides AndLanthanides by Extraction ChromatographyUsing 2,6-BisTriazinyl Pyridine

P. Deepika, K. N. Sabharwal, T. G. Srinivasan and P. R. Vasudeva Rao

Fuel Chemistry Division, Chemistry Group,Indira Gandhi Centre for Atomic Research, Kalpakkam,

603102 India

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Stage Stage –– I PHWRsI PHWRs

•• 1212-- OperatingOperating•• 6 6 -- Under constructionUnder construction•• Several others plannedSeveral others planned•• Scaling to 700 MWeScaling to 700 MWe•• Gestation period being Gestation period being

reducedreduced•• POWER POTENTIAL POWER POTENTIAL ≅≅

10,000 MWe10,000 MWe

LWRsLWRs•• 2 BWRs Operating2 BWRs Operating•• 2 VVERs under 2 VVERs under

constructionconstruction

81

91

8582

8075

7167

60

90868484

7975

6972

90

50

55

60

65

70

75

80

85

90

95

1995-96 1996-97 1997-98 1998-99 1999-00 2000-01 2001-02 2002-03 2003-04

Ava

ilabi

lity/C

apac

ity F

acto

r (%

) ---

-->THREE STAGE NUCLEAR POWER PROGRAMTHREE STAGE NUCLEAR POWER PROGRAM

Stage Stage -- IIIIFast Breeder ReactorsFast Breeder Reactors

•• 40 MWth FBTR 40 MWth FBTR --Operating since 1985Operating since 1985Technology Objectives Technology Objectives realisedrealised

•• 500 MWe PFBR500 MWe PFBR--Under ConstructionUnder Construction

•• POWER POTENTIAL POWER POTENTIAL ≅≅530,000 MWe530,000 MWe

Stage Stage -- IIIIIIThorium Based ReactorsThorium Based Reactors

•• 30 kWth KAMINI30 kWth KAMINI-- OperatingOperating

•• 300 MWe AHWR300 MWe AHWR--Under DevelopmentUnder Development

POWER POTENTIAL IS POWER POTENTIAL IS VERY LARGEVERY LARGEAvailability of Availability of ADS ADS can enable early can enable early introduction of Thorium on introduction of Thorium on a large scalea large scale

DAE Presentation on 24-06-04

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Fast Breeder Test ReactorKalpakkam

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Radiochemistry Laboratory

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Hot Cells

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Minor Actinides

104 105 106 107 108 109

The Chemist's PlaygroundH

Li Be

Na Mg

K Ca Sc Ti V Cr Mn Fe Co Ni Cu Zn Ga Ge As Se Br Kr

Rb Sr Y Zr Nb Mo Tc Ru Rh Pd Ag Cd In Sn Sb Te I Xe

Al Si P S Cl Ar

B C N O F Ne

He

Man-made Radioactive Elements Naturally Radioactive Elements

92 93 94 95 96 97 98 99 100 101 102 103

Cs Ba (Ln) Hf Ta W Re Os Ir Pt Au Hg Tl Pb Bi Po At Rn

Fr Ra (An) Rf Db Sg Bh Hs Mt 110 111 112 113 114 116 118

Minor actinides

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Minor Actinides

DIDPA

TALSPEAK

TRUEX

TPTZ

TRPO

CYANEX301

SASMEHDEHP

Separation of MINOR actinides by various techniques

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Extractants used in our Laboratoryfor Co extraction of lanthanides and actinides

Truex process ---- CMPO ------ Solvent Extraction

Diamides ----- DMDBMA ------- Solvent Extraction[Dimethyl Dibutyl Malonamide]

TEHDGA --- Tetraethyl Hexyl Diglycoamide -- Solvent Extraction

DMDOHEMA ---- Solvent Extraction[DimethylDioctylHexylEthoxyMAlonamide]

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Other Techniques•Extraction Chromatography

•Room Temperature Ionic Liquids

•Supercritical Fluid Extraction

•High Performance Liquid Chromatography

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Actinide – LanthanideSeparation

• Bis Triazinyl Pyridine (BTP)

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Outline • Introduction

– Lanthanide-Actinide Separation.– Bis Triazinyl Pyridines (BTPs).– Advantages of Extraction Chromatography over

Solvent Extraction.• Experimental Work

– Synthesis of 2,6-bis(5,6-dipropyl-1,2,4-triazin-3-yl)pyridine.

– Preparation of the Extraction Resin.– Extraction Studies of Am (III) and trivalent

lanthanides by XAD-7 impregnated with 2,6-bis(5,6-dipropyl-1,2,4-triazin-3-yl)pyridine.

• Conclusions

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• Need– Partitioning and Transmutation ( to reduce long-

term radiological risks to the environment bytransmutation of the minor actinides).

• Difficulty– Lanthanides and actinides have similar

chemical properties due to similar ionic radii.

Lanthanide – Actinide SeparationIntroduction

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Bis Triazinyl Pyridines (BTPs)

First reported in 1999 by Kolarik, Mullich and Gassnerthat 2,6-di(5,6-dialkyl-1,2,4-triazin-3-yl)pyridines extractand separate Am(III) and Eu(III) very efficiently as nitrates.

(Solvent Extraction and Ion Exchange, 17(1), 23-22, 1999)

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Advantages of Extraction Chromatography• No third phase formation,

• No need for a modifier,

• Reusability of the synthesized resin,

• Simple and compact equipment,

• Minimal loss of organic solvent.

Limitations of solvent extraction –

• Third Phase formation,

• Need for phase-modifiers,

• Disposal of large volumes of extractants and diluents,

• Tedious multi-stage extraction procedures.

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Synthesis of 2,6-bis(5,6-dipropyl-1,2,4-triazine-3-yl)-pyridine

NC C

NNH 2

N

N H 2

N H 2

NN

NN N

N

N

NH 2

O

O

2 , 6 - b i s ( 5 , 6 - d ip r o p y l - 1 , 2 , 4 - t r i a z in e - 3 - y l ) p y r i d in e

+

2 , 6 - p y r i d i n e d i c a r b o x a m id e d i h y d r a z o n e

O c t a n e - 4 , 5 - d io n e

Experimental Work

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Preparation of the Extraction ResinResin ImpregnationXAD-7 particles Washing Air-drying

Impregnation in rotary evaporator

Removing DiluentAir-dryingExtraction resin(nPr-BTP/XAD-7)

Extractant: nPr-BTP

Diluent: dichloromethane

(Methanol, Acetone)

(298K, 2h)

(323K)

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“Extraction Studies of Am (III) and trivalentlanthanides by XAD-7 impregnated with 2,6-bis(5,6-dipropyl-1,2,4-triazin-3-yl)pyridine”

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Figure : Kinetics of the uptake of Am (III) by nPr-BTP/XAD-7 resin (0.25g nPr-BTP/XAD-7, 0.1M HNO3, 2M NH4NO3, 303K)

0 5 1 0 1 5 2 0 2 52 0 0

4 0 0

6 0 0

8 0 0

1 0 0 0

1 2 0 0

1 4 0 0

K d

T i m e , h r

• Distribution coefficient (Kd) values increased with increasing time ofequilibration and equilibrium is reached in 24 hours.

• For Kd measurements, we have equilibrated for 3 hours.

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0 .0 0 .5 1 .0 1 .5 2 .0 2 .5 3 .0

0

1 0 0

2 0 0

3 0 0

4 0 0

5 0 0

6 0 0

7 0 0

8 0 0

K d

[ H N O 3 ] , M

W ith o u t N H 4 N O 3 W ith N H 4 N O 3

Figure: Effect of nitric acid concentration on the uptake of Am(III) by nPr-BTP/XAD-7 resinwith and without 2M NH4NO3 (0.25g nPr-BTP/XAD-7, 303K, 3h).

• Kd values for the extraction of Am(III) from nitric acid with ammonium nitrate aresignificantly higher.

• The increase of Am(III) adsorption with increasing nitrate concentration can beexplained by the following adsorption equilibrium represented by Equation (1),

M3+ + 3NO3- + n(nPr-BTP) = M(NO3) 3 (nPr-BTP)n (1)

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Figure : Effect of nitric acid concentration on the uptake of Am(III) and lanthanidesby nPr-BTP/XAD-7 resin (0.25g nPr-BTP/XAD-7, 2 M NH4NO3, 303K, 3h)

0 1 2 3 4

3 0 0

4 0 0

5 0 0

6 0 0

7 0 0

8 0 0 A m ( I I I )

Kd

[ H N O 3 ] , M0 1 2 3 4

0

2

4

6

8

1 0

1 2

1 4

1 6

1 8

2 0 L a ( I I I ) C e ( I I I ) N d ( I I I ) E u ( I I I ) G d ( I I I )

Kd

[ H N O 3 ] , M

• The lanthanides are not extracted by the resin at any acidity.

• Kd value for the extraction of Am(III) is maximum at 0.1M nitric acid in thepresence of ammonium nitrate.

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Figure : Effect of nitrate concentration on the uptake of Am(III) and Lanthanidesby nPr-BTP/XAD-7 resin (0.25g nPr-BTP/XAD-7, 0.1M HNO3, 303K, 3h)

0 1 2 3 4 5 6 7

0

2 0 0

4 0 0

6 0 0

8 0 0

1 0 0 0

A m ( I I I )

Kd

[ N H 4 N O 3 ] , M0 1 2 3 4 5 6 7

- 2 0

0

2 0

4 0

6 0

8 0

1 0 0

1 2 0

1 4 0

L a ( I I I ) G d ( I I I ) N d ( I I I ) C e ( I I I ) E u ( I I I )

Kd

[ N H 4 N O 3 ] , M

The distribution coefficient (Kd) value of Am (III) increases with increase in NH4NO3 concentration, which can be explained by equation (1),

M3+ + 3NO3- + n(nPr-BTP) = M(NO3) 3 (nPr-BTP)n (1)

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[NH4NO3]M

Separation Factor (Kd Am / Kd Ln)

La Ce Nd Eu Gd

0 192 173 173 173 173

1 2730 5187 5187 66 451

2 2471 7638 1400 43 296

3 8925 8926 8926 27 246

4 1412 937 347 14 92

6 770 465 117 7 52

Table: Separation Factors for Americium-Lanthanide Separations ( 0.25g nPr-BTP/XAD-7, 0.1M HNO3, 303K, 3h)

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Figure : Loading of Am (III) and Eu (III) on to a column of nPr-BTP/XAD-7 resin.

0 1 0 2 0 3 0 4 0 5 0 6 0 7 00 .0

0 .2

0 .4

0 .6

0 .8

1 .0

C/C

0

V o lu m e , m L

E u ( I I I ) A m ( I I I )

Europium was not retained in the column and up to 99.4% of it wasrecovered at the loading stage itself. Up to 90% of the Am was retained inthe column.

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Figure : Elution of Am (III) from nPr-BTP/XAD-7 column with 0.3M DTPA.

0 5 1 0 1 5 2 0 2 5 3 0

0

1

2

3

4

5

6

C/C

o

V o l u m e , m L

A m ( I I I ) e l u t i o n w i t h 0 . 3 M D T P A

• Loaded Am(III) was recovered by passing 0.3 M DTPA solution (pH=4.0).

• 60% of Am was recovered within the first three column volumes.

• Further tailing was observed.

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• nPr-BTP impregnated XAD-7 resin displayed highselectivity for americium and good separation-factors forthe separation of other lanthanides from the same.

• Column runs for the separation of americium fromeuropium gave good results with 99.4% Europium beingremoved in the loading stage itself.

• The elution of Am from the column using DTPA wasfound to be 60% and efforts are on to improve the same.

Conclusions -

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Thank You…..