Home Scanning transmission X-ray microscopy as a speciation tool for natural organic molecules
Article
Licensed
Unlicensed Requires Authentication

Scanning transmission X-ray microscopy as a speciation tool for natural organic molecules

  • Jörg Rothe , Markus Plaschke and Melissa A. Denecke
Published/Copyright: December 17, 2007

Summary

A molecular-scale understanding of the basic processes affecting stability and transport behavior of actinide cations, complexes or hydroxide (‘eigencolloid’) species is prerequisite to performance assessment of nuclear waste disposal in geological formations. Depending on their functional group chemistry and macromolecular structure, naturally occurring organic molecules (NOM) possess a high tendency towards actinide complexation reactions. However, the compositional and structural heterogeneity of NOM and mixed aggregates with inorganic phases makes speciation by spectromicroscopy techniques highly desirable. The applicability of Scanning Transmission X-ray Microscopy (STXM) as a speciation tool for the characterization of NOM is demonstrated for a multifunctional natural organic acid (chlorogenic acid), Eu(III)-loaded humic acid (HA) aggregates and Eu(III)-oxo/hydroxide/HA hetero-aggregates. It is shown that in situ probing of HA functional group chemistry down to a spatial resolution <100 nm (i.e., less than femto-liter sampled volumes) is feasible, at the same time revealing morphological details on NOM aggregates and NOM/mineral associations.

Published Online: 2007-12-17
Published in Print: 2004-11-1

© 2004 Oldenbourg Wissenschaftsverlag GmbH

Articles in the same Issue

  1. Preface: Migration Conference 2003
  2. Actinide chemistry: from weapons to remediation to stewardship
  3. Thermodynamics and solubility of (UxNp1-x)O2(am) solid solution in the carbonate system
  4. Solubility and colloid formation of Th(IV) in concentrated NaCl and MgCl2 solution
  5. Effect of reducing agents on the uranium concentration above uranium(IV) amorphous precipitate in Boom Clay pore water
  6. On Mo-Ru-Tc-Pd-Rh-Te alloy particles extracted from spent fuel and their leaching behavior under Ar and H2 atmospheres
  7. Modeling of the complex formation of metal ions with humic acids
  8. Application of the NICA-Donnan model for proton, copper and uranyl binding to humic acid
  9. Protonation and complexation of isosaccharinic acid with U(VI) and Fe(III) in acidic solutions: potentiometric and calorimetric studies
  10. Carbonate complexation of neptunium(IV) in highly basic solutions
  11. Fluorescence characteristics of complex formation of europium(III)-salicylate
  12. The reduction of U(VI) by near field hydrogen in the presence of UO2(s)
  13. Electrochemical aspects of radiolytically enhanced UO2 dissolution
  14. Effect of alpha radiolysis on doped UO2 dissolution under reducing conditions
  15. The redox behaviour of plutonium in humic rich groundwater
  16. The fate of radiolytic oxidants during spent fuel leaching in the presence of dissolved near field hydrogen
  17. Structural changes of uranyl moiety with reduction from U(VI) to U(V)
  18. Trivalent actinide coprecipitation with powellite (CaMoO4): Secondary solid solution formation during HLW borosilicate-glass dissolution
  19. Reproducibility of the uptake of U(VI) onto degraded cement pastes and calcium silicate hydrate phases
  20. Uranium adsorption on weathered schist – intercomparison of modelling approaches
  21. Contribution of minerals to the sorption of U(VI) on granite
  22. Distribution and geochemical association of actinides in a contaminated soil as a function of grain size
  23. Interactions between anionic complex species of actinides and negatively charged mineral surfaces
  24. Measurements and modelling of Pm sorption onto TiO2 and goethite
  25. Effect of humic acid on the sorption of Cm(III) onto γ-Al2O3 studied by the time-resolved laser fluorescence spectroscopy
  26. Am(III) and Eu(III) uptake on hematite in the presence of humic acid
  27. Luminescence properties of tetravalent uranium in aqueous solution
  28. Scanning transmission X-ray microscopy as a speciation tool for natural organic molecules
  29. Formation of hydroxyapatite in soils using calcium citrate and sodium phosphate for control of strontium migration
  30. Influence of humic substances on the 63Ni migration through crushed rock media
  31. U, Th, Eu and colloid mobility in a granite fracture under near-natural flow conditions
  32. Sorption behavior of europium(III) and curium(III) on the cell surfaces of microorganisms
  33. Interactions of trivalent and tetravalent heavy metal-siderophore complexes with Pseudomonas fluorescens
  34. In-situ diffusion of HTO, 22Na+, Cs+ and I- in Opalinus Clay at the Mont Terri underground rock laboratory
  35. Results of the colloid and radionuclide retention experiment (CRR) at the Grimsel Test Site (GTS), Switzerland – impact of reaction kinetics and speciation on radionuclide migration
  36. Fracture flow and radionuclide transport in block-scale laboratory experiments
  37. Comparison between in situ and laboratory diffusion studies of HTO and halides in Opalinus Clay from the Mont Terri
  38. Solubility constraints on uranium concentrations in groundwaters of the Tono uranium deposit, Japan
  39. Mobility of uranium in tertiary argillaceous sediments – a natural analogue study
  40. Redistribution of U, Pb and REE in association with alteration of uranium minerals from the Koongarra deposit, Northern Territory, Australia
  41. Towards a common thermodynamic database for speciation models
  42. Geochemically derived non-gaseous radionuclide source term for the Asse salt mine – assessment for the use of a Mg(OH)2-based backfill material
  43. Simulation of remediation alternatives for a 137Cs contaminated soil
  44. Simulating reactive transport in time dependent multiphase flow problems
  45. Reactive transport modelling of a spent fuel repository in a stiff clay formation considering excavation damaged zones
  46. Coupled transport/reaction modelling of copper canister corrosion aided by microbial processes
Downloaded on 27.9.2025 from https://www.degruyterbrill.com/document/doi/10.1524/ract.92.9.711.55004/html
Scroll to top button