Synchrotron-Based Techniques in Soils and Sediments (eBook)

Front Cover 1
Developments in soil science-Volume 34 4
Copyright Page 5
Table of Contents 6
Chapter 1: The Impacts of X-Ray Absorption Spectroscopy on Understanding Soil Processes and Reaction Mechanisms 10
1. Introduction and Information Gained from XAS 11
2. Complementary/Alternative Techniques 12
3. Historical Aspects of XAS Applications to Mineral/Water Interfacial Reactions 15
4. Applications of XAS to Elucidate Soil Chemical Processes and Reactions 16
5. Future Needs 30
Acknowledgments 30
References 30
Chapter 2: Practical Application of Synchrotron-Based Hard X-Ray Microprobes in Soil Sciences 36
1. The Advent of Hard X-Ray Microprobes to the Analysis of Soils 37
2. An Introduction to Hard X-Ray Microprobes 39
3. X-Ray Sources Commonly Utilized for HXRMs 40
4. HXRM Focusing Optics 41
5. Elemental Analysis by HXRM X-Ray Fluorescence 43
6. HXRM XRF Imaging 48
7. Microfocused X-Ray Absorption Spectroscopy 50
8. Microfocused X-Ray Diffraction 56
9. Applications 64
10. Closing Thoughts 78
Acknowledgments 78
References 79
Chapter 3: Applications of Microtomography in Soils and Sediments 82
1. Introduction: Why is Computed Microtomography Needed? 83
2. Synchrotron-Based X-Ray Microtomography (SR-muCT): Potentials and Limitations 84
3. Principles of Synchrotron Microtomography 86
4. Applications of SR-muCT in Soils and Sediments 89
5. Reconstruction and Image Analysis of 3D Pore Space Networks from SR-muCT Data 92
6. Investigation of Intra-Aggregate Soil Pore Networks: An Example 99
7. Conclusion 106
Acknowledgments 107
References 107
Chapter 4: Synchrotron Infrared Spectromicroscopy for Studying Chemistry of Microbial Activity in Geologic Materials 112
1. Introduction 112
2. Experimental Procedures 117
3. Issues Associated with Spectra Analysis and Interpretation 119
4. Applications 123
5. Limitations 130
6. Prospects and Conclusions 132
Acknowledgments 133
References 134
Chapter 5: Application of Extended X-Ray Emission Fine Structure Spectroscopy in Soil and Sediments 140
1. Introduction 140
2. Extended X-Ray Emission Fine Structure 143
3. Brief Summary of the Structure of Al2O3 and AlPO4 146
4. TEY and XFY Measurements on a Synchrotron Beamline 148
5. Hard X-RAY Absorption Spectroscopy 152
6. Conclusions 152
References 153
Chapter 6: Role of Synchrotron Techniques in USEPA Regulatory and Remediation Decisions 156
1. Introduction 156
2. Application of Synchrotron Techniques to Understand the Impact of Metals in the Environment 158
3. Conclusions 171
Acknowledgment 175
References 175
Chapter 7: The Rhizosphere: A Synchrotron-Based View of Nutrient Flow in the Root Zone 180
1. Introduction 180
2. Effects of Plant Roots on the Rhizosphere Microenvironment 181
3. Plant-Microbe Interactions in the Rhizosphere 182
4. Questions Amenable to Synchrotron-Based Imaging Methods: Opportunities and Challenges 184
5. Synchrotron IR Microscopy: Establishing Models for Rhizosphere Interactions 185
6. Characterizing and Improving Rhizobox Technology: IR Optics Issues 188
7. Plant-Culture Issues 189
8. Polyuronic Acids in Root Mucilage 193
9. Scanning Transmission X-Ray Microscopy Applications in Ecology 196
10. Conclusions 201
Acknowledgments 201
References 201
Chapter 8: Applications of Synchrotron-Based X-Ray Diffraction and X-Ray Absorption Spectroscopy to the Understanding of Poorly Crystalline and Metal-Substituted Iron Oxides 208
1. Introduction 209
2. Crystal Structures of Iron Oxides 211
3. XRD Versus XAS 213
4. Examples of Metal Substitution in Iron Oxides and Synchrotron Applications 223
5. Vanadium Substitution in Goethite: Importance of Oxidation-State-Associated Coordination Environment 226
6. Multiple Metal Substitutions in Goethite 229
7. Multiple Metal Substitutions in Goethite: The Story of Copper 232
8. Natural Goethite Substituted with Multiple Metals 232
9. Iron (III) Oxide Formation from FeSO4 234
10. Metal Substitutions in Hematite 250
11. Effect of Foreign Metal Cations on Akaganéite Formation 251
12. Concluding Remarks 254
Acknowledgments 258
References 259
Chapter 9: Nitrogen Compounds in Dissolved and Solid Environmental Samples 264
1. Introduction 264
2. Beamline Optimization, Sample Preparation, and Data Evaluation 266
3. Applications of N-XANES to Characterize N Functions in Soils 271
4. Conclusions and Outlook 292
Acknowledgments 293
References 293
Chapter 10: Organic Carbon Chemistry in Soils Observed by Synchrotron-Based Spectroscopy 298
1. Introduction 298
2. Synchrotron-Based Techniques and Instrumentation Relevant to C Chemistry in Soils 300
3. Resolving Key Questions in Soil Biogeochemistry 305
4. Prospects for Future Research 316
References 317
Chapter 11: Macroscale Chemical Properties and X-Ray Absorption Spectroscopy of Soil Phosphorus 322
1. Overview of Soil Phosphorus 323
2. Phosphorus Chemistry Derived from Macroscale Research 328
3. X-Ray Absorption Spectroscopy and Phosphorus Speciation 340
4. XANES Analysis of P Species in Agricultural Wastes 358
5. Conclusions 359
Acknowledgments 359
References 360
Chapter 12: Arsenic Chemistry in Soils and Sediments 366
1. Introduction 366
2. Chemistry of Arsenic 367
3. Arsenic Biogeochemistry 371
4. Desorption of Arsenic in Soils and Sediments 373
5. Advancements Through Synchrotron Science 379
6. Summary and Conclusions 380
Acknowledgments 384
References 384
Chapter 13: Mercury Biogeochemistry in Soils and Sediments 388
1. Biogeochemistry of Mercury and the Importance of Chemical Speciation Analysis 389
2. Chemical Speciation of Mercury in Soils and Sediments Using XAS 391
3. Conclusions 415
References 416
Chapter 14: Uranium Chemistry in Soils and Sediments 420
1. Introduction 421
2. Design of a Uranium XAS Experiment 423
3. Uranium XANES Analysis 425
4. Uranium EXAFS Analysis 426
5. XAS Studies 432
6. Summary 466
Acknowledgments 469
References 469
Index 476
Color Plates 490