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:

• Spectroscopic characterization of heavy metal species in aqueous solutions and at mineral surfaces as a function of pH, temperature, and salinity including the impact of redox active complexing compounds.

• Development and parameterization of models describing surface complexation phenomena of heavy metal ions on mineral oxides and rock materials (e.g. natural clays).

• (Radio)chemical analyses of contaminant elements as well as matrix compounds down to the ultratracer level.

• Set-up of thermodynamic data bases for prospective deep nuclear waste repositories.

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Team

Head
Name	Bld./Office	+49 351 260	Email
Prof. Dr. Vinzenz Brendler	801/P250	2430	v.brendler@hzdr.de
Employees
Name	Bld./Office	+49 351 260	Email
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	2438	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	Email
Dr. Harald Foerstendorf	801/P251	3664 2504	h.foerstendorfhzdr.de
Employees
Name	Bld./Office	+49 351 260	Email
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

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