Development of a Simplified Soft-Donor Technique for Trivalent Actinide

232 Pages·2015·4.04 MB·English

Development of a Simplified Soft-Donor
Technique for Trivalent Actinide-
Lanthanide Separations

A thesis submitted to the University of Manchester for the degree of Doctor
of Philosophy in the Faculty of Engineering and Physical Sciences

2015

Madeleine Hilton Langford Paden

School of Chemistry
1
List of Tables 10
List of Figures 14
Abstract 24
Declaration 25
Copyright Statement 26
Acknowledgements 27
List of Symbols & Units 29
List of Abbreviations & Acronyms 31
Amino Acid Abbreviations 34
1. Introduction 35
1.1 The Actinides and Lanthanides 35
1.1.1 Background 35
1.1.2 Sources of the Actinides and Lanthanides 35
1.1.3 Properties of the 4f Elements 36
1.1.4 Properties of the 5f Elements 37
1.1.5 Relativistic Effects 39
1.1.6 Lanthanide and Actinide Contraction 40
1.1.7 Co-ordination Chemistry of the Lanthanides and 40
Actinides in Solution
1.1.7.1 Hydrolysis 41
1.1.7.2 Monodentate Ligands 42
1.1.7.3 Chelates and Macrocycles 42
1.2 Analytical Methods 43
1.2.1 NMR Spectroscopy 43
1.2.2 Luminescence Spectroscopy 43
1.2.2.1 Fluorescence and Phosphorescence 43
1.2.2.2 Lanthanide Luminescence 44
1.2.2.3 Actinide Luminescence 45
1.2.2.4 Sensitised Luminescence and The Antennae 46
Effect 47
1.2.2.5 Russell-Saunders Coupling 48
1.2.2.6 Quenching 48
1.2.2.7 Quenching in Lanthanides and Actinides

2
1.2.2.8 Suitable Solvents for Luminescent Complexes 50
1.3 Nuclear Theory 51
1.3.1 Nuclear Power 51
1.3.2 The Nuclear Fuel Cycle 52
1.3.3 Spent Nuclear Fuel and Reprocessing 53
1.3.4 Solvent Extraction 55
1.3.4.1 PUREX 55
1.3.4.2 TRUEX 57
1.3.4.3 DIAMEX 59
1.3.4.4 SANEX 60
1.3.4.5 iSANEX 62
1.3.4.6 GANEX 63
1.3.4.7 TRPO 65
1.3.4.8 LUCA 67
1.3.4.9 EXAm 68
1.3.7 TALSPEAK 69
1.3.7.1 The Process 69
1.3.8 Reprocessing Summary 74
1.4 Project Objectives and Thesis Outline 75
References 77

2. Complexation Studies of Ln & An with DTPA and Buffers
under TALSPEAK Conditions 81
2.1 Introduction to An-DTPA and Ln-DTPA Complexes 81
2.1.1 Stability of Ln-DTPA and An-DTPA Complexes 82
2.1.2 Co-ordination Chemistry of Ln-DTPA and An-DTPA
Complexes 83
2.2 Ln-DTPA Complexation Studies 84
2.2.1 1H NMR Studies of Ln-DTPA 84
2.2.2 Luminescence Studies of Ln-DTPA 86
2.3 An-DTPA Complexation Studies 88
2.3.1 1H NMR Studies of An-DTPA 88
2.3.2 Luminescence Studies of An-DTPA 89
3
2.4 Introduction to Buffer Interaction with Ln3+ and Ln-DTPA
Complexes 90
2.4.1 Interaction of Lactate with Ln3+ and Ln-DTPA
Complexes 90
2.4.2 Interaction of Amino Acids with Ln3+ and Ln-DTPA
Complexes 92
2.5 Studies on Buffer Interaction with M3+ and [M(DTPA)]2- 93
2.5.1 1HNMR Studies on Buffer Interactions 93
2.5.2 Luminescence Studies on Buffer Interactions 95
2.5.2.1 Sensitisation Tests 95
2.5.2.2 Aqueous Phase Lanthanide Studies without
Na DTPA 96
5
2.5.2.3 Aqueous Phase Lanthanide Studies with
Na DTPA 98
5
2.5.2.4 Aqueous Phase Actinide Studies with
Na DTPA 99
5
2.5.3 Radiolysis Studies on Amino Acid Buffered Systems 100
2.5.3.1 Previous Studies at the INL 100
2.5.3.2 Irradiation Studies using Amino Acid Buffers 102
2.5.4 Buffer Interaction Summary 105
References 106

3. Solvent Extraction and Optimisation Studies with Amino Acid
Buffers 108
3.1 Previous Work at INL 108
3.1.1 L-alanine Studies 108
3.1.1.1 pH Studies on L-alanine 108
3.1.1.2 Concentration Effects 110
3.1.1.3 Studies at pH 2 111
3.1.2 Other Amino Acids 111
3.2 L-alanine System Optimisation at pH 2 113
3.2.1 [Na DTPA] Dependence (Eu/Am) 114
5
3.2.2 [HDEHP] Dependence (Eu/Am) 116
3.2.3 L-alanine Optimisation Summary 118
3.3 Other Amino Acid Studies 119
4
3.3.1 Initial Tests with Other Amino Acids 119
3.3.2 Studies with L-Histidine 120
3.4 Summary of Separations with Amino Acid Buffers 121
References 123

4. Studies using L-Glutathione as a Buffer in a TALSPEAK
System 124
4.1 Solvent Extraction and Separation using GSH 127
4.1.1 [L-Glutathione] and pH Dependence 127
4.1.1.1 [GSH] Dependence without Na DTPA 127
5
4.1.1.2 [GSH] and pH Dependence with
Na DTPA 127
5
4.1.2 [Na DTPA] Dependence at pH 4 132
5
4.1.3 [HDEHP] Dependence at pH 4 133
4.2 Luminescence Studies using GSH with Eu3+ 136
4.2.1 [GSH] and pH Dependence without Na DTPA 137
5
4.2.1.1 Aqueous Phase Studies 137
4.2.1.2 Extraction Studies 139
4.2.2 [GSH] and pH Dependence with Na DTPA 140
5
4.2.2.1 Aqueous Phase Studies 140
4.2.2.2 Extraction Studies 143
4.2.3 [Na DTPA] Dependence at pH 4 145
5
4.2.3.1 Aqueous Phase Studies 145
4.2.3.2 Extraction Studies 148
4.2.4 [HDEHP] Dependence at pH 4 149
4.3 Radiolysis Studies using GSH at pH 4 151
4.3.1 Aqueous Phase Studies 151
4.3.2 Extraction Studies 153
4.4 Luminescence Studies using GSH with Dy3+ 154
4.4.1 Dy3+ Complexation Studies 155
4.4.2 pH Dependence Studies 156
4.5 Luminescence Studies using GSH with Mixed Ln3+
Systems at pH 4 157
4.5.1 Complexation Studies 157
4.5.2 pH Dependence Studies 160
5
4.6 ICP-MS Studies with GSH 163
4.7 1H NMR Studies on GSH Systems 166
4.8 Summary and Conclusion of Glutathione Work 170
References 173

5. Modified DTPA Ligands as Combined Buffers and Soft Donors
in a TALSPEAK System 174
5.1 Ligand Synthesis 175
5.2 Luminescence Studies on Ligand Systems at pH 2, 3 and 4 176
5.2.1 Aqueous Phase Studies 176
5.2.2 Extraction Studies 179
5.3 Radiolysis Studies on Ligand Systems at pH 2 183
5.3.1 Aqueous Phase Studies 183
5.3.2 Extraction Studies 184
5.4 Separation Work on Ligand Systems 185
5.4.1 Am/Eu Separation in Ligand Systems 186
5.4.2 Ln Separation in Ligand Systems 187
5.5 Summary and Conclusion of Modified DTPA Ligand
Work 190
References 191

6. Summary, Conclusions and Future Work 192
6.1 Summary & Conclusions 192
6.2 Future Work 198
References 200

7. Experimental Section 201
7.1 Chemicals and Reagents 201
7.1.1 Handling Radioisotopes at INL 201
7.2 Complexation studies of Ln3+ & An3+ with amino acids in
TALSPEAK systems 201
7.2.1 Preparation of samples for luminescence studies 201
7.2.1.1 Stock solutions 201
7.2.1.2 Preparation of aqueous samples 202
7.2.1.3 Preparation of extracted samples 202
6
7.2.2 Radiolysis of samples 203
7.2.2.1 Preparation of Fricke solution 203
7.2.2.2 Calculating dose rates 203
7.3 Solvent extraction and separation studies using amino
acids and glutathione at INL 205
7.3.1 Preparation of samples 205
7.3.1.1 Stock solutions for amino acid studies 205
7.3.1.2 [Na DTPA] dependence SX samples for
5
amino acid studies 205
7.3.1.3 [HDEHP] dependence SX samples for
amino acid studies 205
7.3.1.4 Other amino acid SX samples for amino
acid studies 206
7.3.1.5 Stock solutions for glutathione studies 206
7.3.1.6 [GSH] dependence SX samples without
Na DTPA 206
5
7.3.1.7 [GSH] and pH dependence SX samples
with Na DTPA 206
5
7.3.1.8 [Na DTPA] dependence SX samples for
5
GSH studies 207
7.3.1.9 [HDEHP] dependence SX samples for
amino acid studies 207
7.3.2 Gamma counting 207
7.3.3 ICP-MS 208
7.4 Luminescence studies and solvent extraction using
glutathione at UoM 208
7.4.1 Preparation of luminescence samples 208
7.4.1.1 Stock solutions for GSH studies 208
7.4.1.2 Preparation of aqueous samples 209
7.4.1.3 Preparation of extracted samples 209
7.4.2 Radiolysis of GSH samples 210
7.4 Modified DTPA Ligands 210
7.5.1 Synthesis of modified DTPA ligands 210
7.5.2 Characterisation of modified DTPA ligands by
MALDI-MS 210
7
7.5.3 Characterisation of modified DTPA ligands by
NMR spectroscopy 211
7.5.3.1 1H NMR Spectroscopy 211
7.5.3.2 13C NMR Spectroscopy 213
7.5.4 Characterisation of modified DTPA ligands by
elemental analysis 215
7.5.5 Luminescence studies with modified DTPA
ligands 216
7.5.5.1 Stock solutions 216
7.5.5.2 Preparation of aqueous samples 216
7.5.5.3 Preparation of extracted samples 216
7.5.5.4 Radiolysis of ligand samples 216
7.6 Instruments 217
7.6.1 FTS MODEL 812 System 60Co Irradiator 217
7.6.2 Edinburgh Instrument FP920 Phosphorescence 217
Lifetime Spectrometer
7.6.3 Packard Cobra II Gamma Counter 218
7.6.4 Bruker UltrashieldTM 400 NMR Spectrometer 218
References 219

Appendices 220
Appendix 1 - Emission spectra for [GSH] pH dependence
studies with DTPA in H O 220
2
Appendix 2 - SF for varying GSH concentration over a
Ln/Am
pH range of 2-4, with 0.05 M Na DTPA after
5
extraction with 0.2 M HDEHP in dodecane 222
Appendix 3 - Natural pH values for modified DTPA ligands
(0.05 M) with Eu(NO3)3 (1 mM) 223
Appendix 4 - APPENDIX 4 - Emission spectra for Eu(NO )
3 3
with modified DTPA ligands in H O 224
2
Appendix 5 - Emission spectra for radiolysis studies on
Eu(NO ) in H O with DTPA-di(amino acid)
3 3 2
ligands. 226
Appendix 6 - MALDI-MS spectrum for DTPA-(AlaOMe) 228
2

8
Appendix 7 - 1H NMR spectrum for DTPA-(AlaOMe) 229
2
Appendix 8 - 1H NMR spectrum for GSH 230
Appendix 8a - 1H NMR spectrum for Eu(NO ) + GSH 231
3 3

Total Word Count: 50,439
9
LIST OF TABLES

Table 1.1: Electronic properties of the lanthanides.
Table 1.2: Electronic properties of the actinides.
Table 1.3: Available oxidation states of the actinides and colours of
ions in solution where applicable.
Table 1.4: Luminescence of lanthanide ions.
Table 1.5: Luminescence of actinide ions.
Table 1.6: Approximate compositions of SNF in Light Water
Reactors (LWR).
Table 2.1: Luminescence lifetimes and q values for Eu3+ with amino
acids/lactate.
Table 2.2: Luminescence lifetimes and q values for [Eu(DTPA)]2-
with amino acids/lactate.
Table 2.3: Separation factors for Eu3+/Am3+ in the presence of L-
alanine at 0.5 M under TALSPEAK conditions when subjected
to different doses of γ-radiation.
Table 2.4: Luminescence lifetimes for aqueous and organic phases for
[Eu(DTPA)]2- systems before and after irradiation at pH 3.6.
Table 2.5: Luminescence lifetimes and q values for [Eu(DTPA)]2-
systems before and after irradiation at pH 3.6.
Table 3.1: Distribution ratios and separation factors for a number of
L-alanine buffered TALSPEAK systems as pH and buffer
concentration are varied, compared to a traditional lactic acid
system.
Table 3.2: Distribution ratios and separation factors for a number of
amino acid buffered TALSPEAK systems.
Table 3.3: Separation factors for L-alanine optimisation studies.
Table 3.4: D values for L-alanine optimisation studies.
Am
Table 3.5: Separation factors and D values for traditional
Am/Eu
TALSPEAK systems with different buffers at varying pH
values.
Table 4.1: Eu3+/Am3+ distribution and separation for [GSH]
dependence with 0.05 M Na DTPA at pH 4.
5

10