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
In search of phytoremediation candidates: Eu(III) bioassociation and root exudation in hydroponically grown plants
Klotzsche, M.; Dück, V.; Drobot, B.; Vogel, M.; Raff, J.; Stumpf, T.; Steudtner, R.
Abstract
Lanthanides and actinides are emerging contaminants, but little is known about their uptake and distribution by plants and their interactions in the rhizosphere. To better understand the fate of these metals in plants, we assessed the bioassociation of 2, 20 and 200 µM Eu(III) by five hydroponically grown crops endemic to Europe. The metal’s concentration and its speciation was monitored by inductively coupled plasma mass spectrometry and laser spectroscopy, whereas root exudation was investigated by chromatographic methods. It has been shown, that Eu(III) bioassociation is a two-stage process, involving rapid biosorption followed by accumulation in root tissue and distribution to the stem and leaves. Within 96 h of exposure time, the plant induces a change of Eu(III) speciation in the liquid medium, from a predominant Eu(III) aquo species, as calculated by thermodynamic modelling, to a species with longer luminescence lifetime. Root exudates such as citric, malic, and fumaric acid were identified in the cultivation medium and affect Eu(III) speciation in solution, as was shown by a change in the thermodynamic model. These results contribute to a comprehensive understanding of the fate of lanthanides in the biosphere and provide a basis for further investigations with the chemical analogues Cm(III) and Am(III).
Keywords: europium; speciation; phytoremediation; bioassociation; laser spectroscopy; lanthanides; hydroponics; plant uptake; root exudates; thermodynamic modelling
Related publications
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Data publication: In search of phytoremediation candidates: Eu(III) …
ROBIS: 39228 HZDR-primary research data are used by this (Id 39219) publication -
Data publication: In search of phytoremediation candidates: Eu(III) …
RODARE: 3027 HZDR-primary research data are used by this (Id 39219) publication
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Minerals 14(2024)8, 754
DOI: 10.3390/min14080754
Permalink: https://www.hzdr.de/publications/Publ-39219
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-biondo![]() | ||||
Viktor Dück | 801/P306 | 3241 | v.dueck![]() | ||
Alexandra Duckstein | 801/P153 | 2774 | a.duckstein![]() | ||
Dr. Stephan Hilpmann | 801/P306 | 2860 | s.hilpmann![]() | ||
Dr. Jerome Kretzschmar | 801/P207 | 3136 | j.kretzschmar![]() | ||
Dr. Elmar Plischke | e.plischke![]() | ||||
Dr. Solveig Pospiech | 801/P205 | 2438 | s.pospiech![]() | ||
Dr. Anke Richter | 801/P202 | 2426 | anke.richter![]() | ||
Dr. Katja Schmeide | 801/P208 | 2436 2513 | k.schmeide![]() | ||
Salim Shams Aldin Azzam | 801/P348 | 2386 | s.shams![]() | ||
Claudia Sieber | 801/P254 | 2251 | c.sieber![]() | ||
Susanne Zechel | 801/P352 | 3328 | s.zechel![]() |
Analytics
Head | |||||
Name | Bld./Office | +49 351 260 | |||
---|---|---|---|---|---|
Dr. Harald Foerstendorf | 801/P251 | 3664 2504 | h.foerstendorf![]() | ||
Employees | |||||
Name | Bld./Office | +49 351 260 | |||
Sabrina Beutner | 801/P203 | 2429 2528 | s.beutner![]() | ||
Tim Gitzel | 801/P316 | 2025 | t.gitzel![]() | ||
Dominik Goldbach | 801/P203 | 3198 | d.goldbach![]() | ||
Karsten Heim | 801/P201 | 2434 2504 | k.heim![]() | ||
Sylvia Schöne | 801/P203 | 3198 2526 | s.schoene@hzdr.de, s.guertler![]() |