Contact

Porträt Dr. Müller, Katharina; FWOG — Photo: André Wirsig

Dr. Katharina Müller

Head Surface Processes
k.muellerhzdr.de
Phone: +49 351 260 2439

Social Media

Department of Surface Processes

The why? The how? The what?

The ultimate goal of our research, driven by scientific curiosity, is to gain fundamental and independent knowledge of the (geo)chemistry and environmental fate of long-lived radionuclides (RNs). One prominent and socially important application is the safe disposal of radioactive waste, to aid future generations in the responsibility of dealing with “our” legacy from energy production in nuclear reactors.

For this purpose we provide the radiochemical knowledge, namely structural and mechanistic data of important mobilizing and immobilizing reactions of RNs in solution, at interfaces, and in solids.

Our particular focus is using a variety of established and advanced microscopic and spectroscopic techniques, to accurately describe complex formation reactions and complex structures that govern RN interactions in the geosphere. In addition, we investigate the creation and chemical speciation of activation products in materials from nuclear power plants in the context of their safe decommissioning.

As part of a value chain, the derived structural information forms a sound basis for a reliable thermodynamic description of the investigated systems, which can be integrated in thermodynamic databases. The thermodynamic work is done in close collaboration with the department of Actinide thermodynamics.

Foto: Forschungsfelder der Abteilung Grenzflächenprozesse ©Copyright: Dr. Katharina Müller

Our core competencies

Chemistry of long-lived RNs – Expertise in handling RNs, ranging from fission- and activation products to transuranium elements, and access to radiation safety labs.
Structural characterization – Expertise in applying and coupling spectroscopic and microscopic as well as diffraction techniques for accessing molecular information.
Thermodynamic description of RN complexes – Using macroscopic, spectroscopic, and calorimetric information of reactant-water-surface phenomena as basis for the derivation of surface complexation models and their thermodynamic parameters.

Research fields

Coordination chemistry of RNs in aqueous solution and in human artificial biofluids, e.g. RADEKOR project.
Molecular characterization of RN reactions at natural and engineered mineral-water interfaces, e.g. REDOX project.
Incorporation of actinides and lanthanides in solid phases, e.g. AcE project.
Environmental technetium chemistry., e.g. Young Investigator Group TecRad.
Development of a method for pre-activity and dose rate calculations of components in the reactor vicinity based on neutron fluence distributions (EMPRADO) 12/2018 –11/2022, BMBF.

Latest Publication

Eu(III) and Cm(III) Complexation by the Aminocarboxylates NTA, EDTA, and EGTA Studied with NMR, TRLFS, and ITC – An Improved Approach to More Robust Thermodynamics

Friedrich, S.; Sieber, C.; Drobot, B.; Tsushima, S.; Barkleit, A.; Schmeide, K.; Stumpf, T.; Kretzschmar, J.

The complex formation of Eu(III) and Cm(III) was studied with tetradentate, hexadentate, and octadentate coordinating ligands of the aminopolycarboxylate family, viz. nitrilotriacetate (NTA³⁻), ethylenediaminetetraacetate (EDTA⁴⁻), and ethylene glycol-bis(2-aminoethyl ether)-N,N,N′,N′-tetraacetate (EGTA⁴⁻), respectively. Based on the complexones’ pKa values obtained from ¹H nuclear magnetic resonance (NMR) spectroscopic pH titration, complex formation constants were determined by means of parallel-factor-analysis-assisted evaluation of Eu(III) and Cm(III) time-resolved laser-induced fluorescence spectroscopy (TRLFS). This was complemented by isothermal titration calorimetry (ITC), providing the enthalpy and entropy of the complex formation. This allowed us to obtain genuine species along with their molecular structures and corresponding reliable thermodynamic data. The three investigated complexones formed 1:1 complexes with both Eu(III) and Cm(III). Besides the established Eu(III)–NTA 1:1 and 1:2 complexes, we observed, for the first time, the existence of a Eu(III)–NTA 2:2 complex as of millimolar metal and ligand concentrations. Demonstrated for thermodynamic studies on Eu(III) and Cm(III) interaction with complexones, the utilized approach is commonly applicable to many other metal–ligand systems, even to high-affinity ligands.

Keywords: Europium; Curium; Metal complex; Spectroscopy; Calorimetry; Stability constant; High-affinity ligand

Molecules 28(2023)12, 4881
Online First (2023) DOI: 10.3390/molecules28124881

A list of publications can be found here.

Research groups

Currently running third-party funded projects

Interactions of technetium with microorganisms, metabolites and at the mineral-water interface – Radioecological considerations (TecRad) 07/2022 – 06/2027, BMBF
Redox reactivity of selenium in environmental geomedia (REDOX) 06/2022 – 05/2025, ANDRA
Speciation and transfer of radionuclides in the human organism especially taking into account decorporation agents (RADEKOR) 07/2020 – 12/2023, BMBF.
Fundamental investigations of actinide immobilization by incorporation into solid phases relevant for final disposal (AcE) 01/2021 – 12/2023, BMBF.
Means for efficient decommissioning of reactor components and concrete shielding: Calculation of the activity inventory and their validation on drilling cores as well as mobility investigations of radionuclides (WERREBA) 07/2019 – 12/2022, BMBF.

An overview of finished projects can be found here.

Team

Name	Bld./Office	+49 351 260	Email
Head
Dr. Katharina Müller	801/P248	2439	k.muellerhzdr.de
Employees
Name	Bld./Office	+49 351 260	Email
Daniel Butscher	801/P352	3154	d.butscherhzdr.de
Aline Chlupka	801/P203	3198 2518 2523	a.chlupkahzdr.de
Sebastian Friedrich	801/P352	3154	s.friedrichhzdr.de
Dr. Norbert Jordan	801/P218	2148	n.jordanhzdr.de
Christa Müller		3198 2538	c.muellerhzdr.de
Stephan Weiß	801/P316	2758 2523	s.weisshzdr.de
Incorporation in solid phases
Name	Bld./Office	+49 351 260	Email
Dr. Nina Maria Huittinen	801/P218	2148	n.huittinenhzdr.de
Dr. Astrid Barkleit	801/P207	3136 2512 2518	a.barkleithzdr.de
Luiza Braga Ferreira dos Santos	801/P254	3487	l.bragahzdr.de
"TecRad" Wechselwirkung von Technetium mit Mikroorganismen, Metaboliten und an Mineral-Wasser-Grenzflächen - Radioökologische Betrachtungen
Name	Bld./Office	+49 351 260	Email
Dr. Natalia Mayordomo Herranz	801/P252	2076	n.mayordomo-herranzhzdr.de
Caroline Börner			c.boernerhzdr.de
Irene Cardaio	801/P254	2251	i.cardaiohzdr.de
Vijay Kumar Saini	801/P352	3328	v.sainihzdr.de

Alumni

Name	at HZDR	Derzeitigte Institution
Quirina Isabella Roode-Gutzmer	Ph.D. student	Fraunhofer-Institut für Keramische Technologien und Systeme IKTS
Maximilian Demnitz	Ph.D. student, graduated 2022	Eindhoven University of Technology, Department of Chemical Engineering and Chemistry, Het
Diana Marcela Rodriguez Hernandez	Ph.D. student, graduated 2021	Rotop Pharmaka GmbH
Henry Lösch	Ph.D. student, graduated 2021	Radiation Protection, Analytics & Disposal (VKTA)
Manuel Eibl	Ph.D. student, graduated 2020	Avantgarde Labs GmbH
Susanne Lehmann	Ph.D. student, graduated 2020	Institute for Geosciences at the Friedrich-Schiller-University Jena