Empa - the place where innovation starts

Empa is the research institute for materials science and technology of the ETH Domain and conducts cutting-edge research for the benefit of industry and the well-being of society.

Karlsruhe Institute of Technology (KIT) is one of the largest science and engineering research institutions in Europe and funded jointly by the Federal Republic of Germany and the State of Baden-Wuerttemberg. Its research and development program is embedded in the superordinate program structure of the Helmholtz Association of National Research Centers. The Institute for Nuclear Waste Disposal (INE) at KIT is strongly focusing on safety research for radioactive waste disposal by investigation of geochemical processes relevant for assessing long-term behavior of waste forms and (geo-)technical and natural barriers.

 

For a research project on “Cement-organics-radionuclide interactions” – CORI, integrated into the EC funded EURAD frame, we are looking for a highly motivated

PhD Student - Impact of citrate and formate on the uptake of tri- and tetravalent actinides by cement and pure cement phases (C-S-H, AFm): structural and thermodynamic study

Your tasks

Cement is the most widely used building material. Different types of cements are used for the stabilization of nuclear waste and for construction purposes in the context of nuclear waste disposal. In addition to its structural properties, cement phases also have the ability to bind radionuclides. Calcium silicate hydrates (C-S-H phases) strongly sorb metal cations (e.g. actinides), whereas the so-called AFm-phases can bind anions (e.g. sulfate, carbonate, etc.) in their interlayer due to their positively charged main layer. The presence of organic ligands can affect these properties due to their complexation to radionuclides, alteration of the cement surface properties or incorporation in the cement phases (AFm). The planned PhD study will investigate key processes looking both from the cement and radionuclide side.

In the first part of this PhD performed at Empa, you will synthesize cement, C-S-H and AFm phases in the laboratory and study their ability to sorb / incorporate citrate and formate. The resulting materials will be thoroughly characterized by X-ray diffraction, thermogravimetric analysis and synchrotron techniques. Thermodynamic properties of AFm-doped phases will be determined. The second part of this PhD performed at KIT-INE will focus on the interaction of tri- and tetravalent actinides with cement and pure cement phases in the absence and in the presence of citrate and formate. Solid and aqueous phases in these systems will be characterized by a multifold of experimental techniques, all available at KIT-INE (TRLFS, XPS, XAFS, XRD, NMR, SEM-EDS). This information will provide the basis for the quantification and modelling of the uptake process in the presence organic ligands. The present PhD is part the CORI workpackage integrated into the collaborative project (EURAD) funded by the European Commission. You will be expected to cooperate with other PhD projects and to actively participate in international workshops.

This challenging PhD project will be partially developed at KIT (1.5 years), partially at Empa (1.5 years). The PhD degree will be awarded by Karlsruhe Institute of Technology.

Your profile

We are looking for a student with a master in Chemistry, Materials Science, Earth Sciences, or related fields, who has good verbal and written knowledge in English. A strong background in materials science or inorganic chemistry, good skills in design and operation of experimental set-ups and experience in radiochemistry are an advantage. If you are motivated researcher who likes to work in an international, interdisciplinary environment, then you are the person we are looking for.

 

We offer

Our institutions are based on an interdisciplinary, innovative and dynamic collaboration. You will profit from a systematic training on the job, in addition to personal development possibilities and our pronounced vocational training culture. If you wish to optimally combine work and family life or other personal interests, we are able to support you with our modern employment conditions and the on-site infrastructure.

For further information about the position please contact Prof Dr Horst Geckeis, horst.geckeis@kit.edu or Dr Barbara Lothenbach, barbara.lothenbach@empa.ch and visit our websites www.empa.ch/web/s308 and Empa-Video

We look forward to receiving your online application including a letter of motivation, CV, diplomas with transcripts and contact details of two referees. Please upload the requested documents through our webpage. Applications via email will not be considered.

Empa, Patricia Nitzsche, Human Resources, Ueberlandstrasse 129, 8600 Dübendorf, Switzerland.