Actinide thermodynamics department
Research
The research topics of the Department of Actinide Thermodynamics within the Institute of Resource Ecology are clustered around the determination of thermodynamic (and kinetic) parameters, their evaluation, processing, storage in respective databases and utilization for geochemical modeling. From a chemical point of view the focus is set on heavy metal contaminants, namely long-lived radionuclides. Their environmental fate, including migration and entrance into the food chain is of paramount societal concern. Respective precaution, detoxification, separation and remediation measures need to be designed on the basis of a mechanistic understanding of all relevant physico-chemical processes. Then in turn a realistic, i.e. precise and robust forecast of their dissemination in geo- and biosphere and the risk involved for human health becomes possible.
Whereas the thermodynamic of aquatic species is often quite well understood, the picture is different for surface processes such as surface complexation, ion exchange, mineral transformation and surface precipitation - all of them considered important retardation mechanisms in complex environmental systems. With respect to solid phases research primarily deals with those minerals dominati
ng most rocks and soils. Prominent examples are the rock-forming constituents of crystalline rocks such as quartz, feldspars and mica, or alumosilicates such as kaolinite, illite, or montmorillonite. Engineered systems of interest are iron minerals and cementitious compounds.
Based on own investigations but also strongly embedded in the research topics of other departments (namely Surface Processes, Chemistry of the f-Elements, Molecular Structure and Biogeochemistry) the identification of (surface) species and development of molecular models lays the foundation of realistic sets of species and their reaction equations - usually called model development. In a second step formation constants and other thermodynamic parameters are determined through experimental series under varying boundary conditions like pH, redox potential, ionic strength, temperature or CO2 partial pressure. This allows for the parameterization of the models derived afore. Species sets, reactions and parameters then support the compilation of respective geochemical databases providing required for the assessment of the macroscopic migration behavior of the long-lived radionuclides. Respective codes are shared with the department of Reactive Transport, where the team also provides many aspects of surface characterizations needed for our own model development. Another overarching goal is a tiered approach towards upscaling from the nano- to the macro scale, bridging the distance between atomistic investigations and the large scale prognostics required e.g. in performance assessment of nuclear waste repositories and covering distances of several km over up to one million years.
The actual major research topics of our department can be su
mmarized as follows:
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(Radio)chemical analyses of contaminant elements as well as matrix compounds down to the ultratracer level.
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Set-up of thermodynamic data bases for prospective deep nuclear waste repositories.
Latest publication
A critical review of the solution chemistry, solubility, and thermodynamics of europium: recent advances on the Eu(III) hydrolysis
Jordan, N.; Thoenen, T.; Spahiu, K.; Kelling, J.; Starke, S.; Brendler, V.
This review is aiming at providing a critical assessment of the published complexation constants and solubility products related to the hydrolysis of Eu(III) in aqueous medium. Original experimental data available from peer-reviewed scientific publications were the main source for the selection of thermodynamic data, together with technical reports and Eu(III)-data-containing thermodynamic databases starting from around 1900 until July 2023. The methodology followed by the Thermochemical Database Project of the Nuclear Energy Agency, which uses the Specific ion Interaction Theory (SIT) for describing activity coefficients in aqueous electrolyte solutions, was strictly applied, with a few minor deviations, however. The selected and rejected literature data were thoroughly discussed as well as the procedures enabling the derivation of recommended complexation constants, solubility products, thermodynamic functions at infinite dilution (1 bar, 25 °C), together with ion interaction coefficients ε(j;k). These recommended data complement our former study on the chloride, sulphate, and phosphate ligands and will further contribute to the establishment of a comprehensive, internally consistent, and reliable thermodynamic reference database for the chemical, geochemical, and chemotechnical modeling of europium.
Keywords: Europium; thermodynamic database; complexation constant; solubility product; hydrolysis; SIT
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Coordination Chemistry Reviews 510(2024), 215702
DOI: 10.1016/j.ccr.2024.215702
Team
Head | |||||
Name | Bld./Office | +49 351 260 | |||
---|---|---|---|---|---|
Prof. Dr. Vinzenz Brendler | 801/P250 | 2430 | v.brendler@hzdr.de | ||
Employees | |||||
Name | Bld./Office | +49 351 260 | |||
Dr. Frank Bok | 801/P202 | 3551 | f.bok@hzdr.de | ||
Rodrigo Castro Biondo | r.castro-biondohzdr.de | ||||
Viktor Dück | 801/P306 | 3241 | v.dueckhzdr.de | ||
Alexandra Duckstein | 801/P153 | 2774 | a.ducksteinhzdr.de | ||
Dr. Stephan Hilpmann | 801/P306 | 2860 | s.hilpmannhzdr.de | ||
Dr. Jerome Kretzschmar | 801/P207 | 3136 | j.kretzschmarhzdr.de | ||
Dr. Elmar Plischke | e.plischkehzdr.de | ||||
Dr. Solveig Pospiech | 801/P205 | 2011 | s.pospiechhzdr.de | ||
Dr. Anke Richter | 801/P202 | 2426 | anke.richterhzdr.de | ||
Dr. Katja Schmeide | 801/P208 | 2436 2513 | k.schmeidehzdr.de | ||
Salim Shams Aldin Azzam | 801/P348 | 2386 | s.shamshzdr.de | ||
Claudia Sieber | 801/P254 | 2251 | c.sieberhzdr.de | ||
Susanne Zechel | 801/P352 | 3328 | s.zechelhzdr.de |
Analytics
Head | |||||
Name | Bld./Office | +49 351 260 | |||
---|---|---|---|---|---|
Dr. Harald Foerstendorf | 801/P251 | 3664 2504 | h.foerstendorfhzdr.de | ||
Employees | |||||
Name | Bld./Office | +49 351 260 | |||
Sabrina Beutner | 801/P203 | 2429 2528 | s.beutnerhzdr.de | ||
Tim Gitzel | 801/P316 | 2025 | t.gitzelhzdr.de | ||
Dominik Goldbach | 801/P203 | 3198 | d.goldbachhzdr.de | ||
Karsten Heim | 801/P201 | 2434 2504 | k.heimhzdr.de | ||
Sylvia Schöne | 801/P203 | 3198 2526 | s.schoene@hzdr.de, s.guertlerhzdr.de |