Department of Surface Processes
A detailed knowledge of the molecular processes determining the migration behavior of heavy metal contaminants, namely long-lived radionuclides, in the environment is mandatory for the assessment of their dissemination and the risk involved for human health. A deep understanding of these processes, which in general are strongly related to the host rock in the in the near and far field of the considered site, is fundamental for the development of new detoxification, separation and remediation strategies but also for the design of a deep underground waste repository. Thus, a characterization and ranking of the most relevant interactions of radionuclides with mineral surfaces, but also the aqueous chemistry of these heavy metals, represents the central scope of the Department of Surface Processes of the Institute of Resource Ecology. The Helmholtz-funded Young Investigator Group "Structures and Reactivity at the Water/Mineral Interface" substantially supports these activities.
In this context, the exploration of complex systems, such as the sorption processes on naturally occurring mineral surfaces, the aqueous speciation and colloid forming processes within a wide range of environmental parameters becomes essential. From the results obtained, the identification of (surface) species and development of molecular models comprehensively describing the mechanisms of transport and retention of the radionuclides in the environment can be achieved. These models are expanded into the compilation of databases providing reliable parameter sets for the assessment of the macroscopic migration behavior of the long-lived radionuclides.
The actual major research topics of the department can be summarized 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). (→)
- Investigation of the complexation behavior of long-lived radionuclides with organic compounds and biomolecules in aqueous media.
- Identification and characterization of colloidal nanoparticles of actinides and their relevance for radionuclide transport in the environment (from the source of radionuclide to man’s food chain).(→)
- Set-up of thermodynamic data bases for prospective deep nuclear waste repositories. (→)
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