Speciation of tetravalent plutonium in contact with humic substances and kaolinite under environmental conditions [Elektronische Ressource] / Nidhu lal Banik

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Informations

• Publié par: johannes_gutenberg-universitat_mainz
• Publié le: 01 janvier 2006
• Nombre de lectures: 11
• Langue: English
• Poids de l'ouvrage: 4 Mo

Extrait

Speciation of Tetravalent Plutonium in Contact with
Humic Substances and Kaolinite under
Environmental Conditions




Thesis submitted for
attaining the degree of

“Doktor der Naturwissenschaften”
doctor rerum naturalium





at the
Department of Chemistry, Pharmacy, and Geosciences
of the
Johannes Gutenberg-University Mainz




Nidhu lal Banik
Born in Noakhali, Bangladesh



Mainz, 2006






















To My Family Contents I
Contents

Zusammenfassung..............................................................................................................IV
Abstract...............................................................................................................................V
1.0 Introduction..................................................................................................................1
2.0 Theoretical Part............................................................................................................5
2.1 Actinide Chemistry.....................................................................................................5
2.1.1 Historty...............................................................................................................5
2.1.2 Actinide solution chemistry.................................................................................7
2.1.3 Hydrolysis and solubility of Th(IV) and Np(IV)..................................................8
2.1.4 Complexation, sorption, and colloids of Th(IV) and Np(IV))............................11
2.2 Plutonium Chemistry................................................................................................13
2.2.1 Physical and chemical properties.......................................................................14
2.2.2 Plutonium solution chemistry............................................................................15
2.2.3 Redox chemistry, complexation, sorption, and colloids of plutonium................17
2.3 Radioactive Waste Disposal and Repository.............................................................20
2.3.1 Types of radioactive waste................................................................................21
2.4 Actinides in the Environment....................................................................................26
2.5 Aqueous Chemistry..................................................................................................28
2.5.1 Humic chemistry...............................................................................................28
2.5.2 Actinide complexation with humic substances..................................................31
2.5.3 Kaolinite...........................................................................................................34
2.5.4 Interaction of actinides with kaolinite................................................................35
2.5.5 Interaction of kaolinite with organic matter.......................................................36
2.5.6 Speciation of actinides in aquatic systems.........................................................38
2.5.7 Speciation of actinides by direct methods..........................................................39
2.5.8 Speciation of actinides by indirect methods.......................................................40
2.6 CE-ICP-MS..............................................................................................................41
2.6.1 Online coupling of capillary electrophoresis (CE) with ICP-MS........................44
2.7 Resonance ionization mass spectrometry (RIMS).....................................................47
2.7.1 CE-RIMS..........................................................................................................48
3.0 Experimental Part......................................................................................................51
3.1 Chemicals and Reagents...........................................................................................51 II Content
3.1.1 Humic substances.............................................................................................56
3.1.2 Kaolinite...........................................................................................................57
3.2Radiometric Techniques...........................................................................................57
3.3 Other Techniques......................................................................................................59
3.3.1 UV-Vis spectroscopy........................................................................................59
3.3.2 Inductively coupled plasma mass spectrometry (ICP-MS).................................61
3.3.3 X-Ray absorption fine structure spectroscopy (XAFS)......................................62
3.3.4 X-ray photoelectron spectroscopy (XPS)...........................................................63
3.4 Liquid-Liquid Extraction Technique.........................................................................64
3.5 Ultrafiltration and Centrifugation Method.................................................................65
3.6 Batch Experiments....................................................................................................66
3.6.1 Binary system...................................................................................................67
3.6.2 Ternary system..................................................................................................69
3.7 Production of the Plutonium Oxidation States by Electrolysis...................................71
3.8 Preparation of Neptunium(IV) by Chemical Treatment.............................................72
4.0 Results and Discussions..............................................................................................74
4.1.1 Reduction of Pu(VI) in contact with fulvic acid.................................................74
4.1.2 Reduction of Pu(VI) in contact with humic acid................................................76
4.1.3 Comparison of the reduction studies of plutonium by humic and fulvic acid.....78
4.2 Complexation of Tetravalent Plutonium with Humic Substances..............................79
4.2.1 Determination of loading capacity of Pu(IV) with Aldrich humic acid..............82
4.2.2 Complexation constants of plutonium(IV) with Aldrich humic acid..................83
4.2.3 Complexation of tetravalent neptunium with humic substances.........................85
4.3 Precipitation of Aldrich Humic Acid as a function of pH..........................................87
4.3.1 Limitation of the ultrafiltration method for the determination of complextation
constants with humic substances.......................................................................88
4.3.2 Limitation of the ultrafiltration method for the determination of complextation
. constants of Pu(IV) with humic substances.......................................................90
4.4 Sorption of Tetravalent Plutonium onto Kaolinite...................................................91
4.4.1 Speciation of Pu(IV) in aqueous system............................................................91
4.4.1.1 Effect of contact time on the sorption of Pu(IV) onto kaolinite.....................92
4.4.1.2 Effect of pH on the sorption of Pu(IV) onto kaolinite...................................93
4.4.1.3 Speciation of plutonium in contact with kaolinite by liquid-liquid extraction94 Contents III
4.4.1.4 Desorption of plutonium from kaolinite........................................................95
4.4.2 Sorption of Th(IV) onto kaolinite.....................................................................95
4.4.2.1 Effect of contact time on the sorption of Th(IV) onto kaolinite.....................96
4.4.2.2 Effect of pH on the sorption of Th(IV) onto kaolinite...................................96
4.4.2.3 Comparison of the sorption behavior of Pu(IV) and Th(IV).......................... 98
4.4.3 Comparison of the sorption behavior of Pu(IV), Th(IV), Am(III), Pu(III), and
other actinides..................................................................................................99
4.4.4 XAFS study of the sorption of plutonium onto kaolinite..................................101
4.5 Sorption of Humic Substances onto Kaolinite.........................................................103
4.6 Sorption of Tetravalent Plutonium and Thorium onto Kaolinite in the Presence of
Humic Substances ……………………………………………..................................110
4.6.1 Sorption of Pu(IV) onto kaolinite in presence and absence of fulvic acid.........111
4.6.2 Sorption of Pu(IV) onto kaolinite in presence and absence of humic acid........115
4.6.3 Sorption of Th(IV) onto kaolinite in presence and absence of fulvic acid........118
5.0 Conclusions and Outlook.........................................................................................121
6.0 Literature..................................................................................................................125
7.0 Appendix