A5015246619- Radioactive element chemistry and processing
- Crystallization and Solubility Studies
- X-ray Diffraction in Crystallography
- Lanthanide and Transition Metal Complexes
- Geochemistry and Elemental Analysis
- Nuclear materials and radiation effects
- Crystallography and molecular interactions
- Radioactive contamination and transfer
- Analytical chemistry methods development
- Geochemistry and Geologic Mapping
- Organometallic Complex Synthesis and Catalysis
- Nuclear Materials and Properties
- Metal Extraction and Bioleaching
- Chemical Synthesis and Characterization
- Groundwater flow and contamination studies
- CO2 Sequestration and Geologic Interactions
- Mine drainage and remediation techniques
- Minerals Flotation and Separation Techniques
- Clay minerals and soil interactions
- Soil and Unsaturated Flow
- Hydrocarbon exploration and reservoir analysis
- Synthesis and characterization of novel inorganic/organometallic compounds
- Atmospheric and Environmental Gas Dynamics
- Iron oxide chemistry and applications
- Luminescence Properties of Advanced Materials
Helmholtz-Zentrum Dresden-Rossendorf
2016-2025
TU Dresden
2014-2025
Karlsruhe Institute of Technology
2009-2014
FZI Research Center for Information Technology
2004-2011
Heidelberg University
2006-2010
Scherrer (Switzerland)
2008
Forschungszentrum Jülich
2007
European Synchrotron Radiation Facility
2006
Paul Scherrer Institute
2003
Goethe University Frankfurt
1996-2000
ROBL-II provides four different experimental stations to investigate actinide and other alpha- beta-emitting radionuclides at the new EBS storage ring of ESRF within an energy range 3 35 keV. The XAFS station consists a highly automatized, high sample throughput installation in glovebox, measure EXAFS conventional XANES samples routinely temperatures down 10 K, with detection limit sub-p.p.m. range. XES its five bent-crystal analyzer, Johann-type setup Rowland circles 1.0 0.5 m radii...
The present paper describes the surface complexation behaviour of trivalent metal ions, Am(III) and Eu(III), on well characterised γ-alumina. Experiments are conducted at different pH (4-8) ionic strength (0.001 - 0.1 M NaClO 4 ) either in presence or absence CO 2 . By varying ion concentration from 10 -9 to -4 mol/L, sorption isotherm is established under each given experimental condition. Different models applied results interpret appraise processes conditions. A comparison made with...
Summary The surface sorption process of Eu(III) onto smectite and kaolinite was investigated by time-resolved laser fluorescence spectroscopy (TRLFS) in the trace concentration range. experiments were performed 0.025 M 0.45 NaClO 4 . obtained TRLFS under atmospheric conditions absence CO 2 pH varied between 3.5 9 at a fixed metal ion 3.3 × 10 −6 mol/L Eu(III). At low (< 4) keeps its complete hydration sphere indicating outer-sphere complexation. With increasing formation an inner-sphere...
Summary The structure parameters of the Am 3+ aquo ion and Am(III) sorbed onto smectite kaolinite at varying pH are analyzed using EXAFS. An Am-O distance 2.47-2.49Å is found a coordination number 8-9 oxygen atoms observed for its hydration sphere. Combined TRLFS (Cm(III)) EXAFS (Am(III)) results show that An(III) sorbs 4, forming an outer-sphere complex retains complete primary With increasing pH, inner-sphere sorption occurs. overall coordinating actinide remains about same 6, with four...
In the presence of polyborates (detected by (11)B-NMR) formation a weak Eu(III) borate complex (lg β11 ~ 2, estimated) was observed time-resolved laser-induced fluorescence spectroscopy (TRLFS). This is precursor for solid species. The this in solution investigated TRLFS as function total boron concentration: lower concentration, slower formation. characterized IR spectroscopy, powder XRD and solid-state TRLFS. determination europium to ratio portends existence pentaborate units amorphous solid.
Abstract The reactivity of calcite, one the most abundant minerals in earth’s crust, is determined by molecular details its interface with contacting solution. Recently, it has been found that trace concentrations NaNO 3 severely affect calcite’s (104) surface and reactivity. Here we combine dynamics (MD) simulations, X-ray reflectivity (XR) situ atomic force microscopy (AFM) to probe calcite – water presence . Simulations reveal density profiles different ions near surface, NO − able reach...
This study represents a first comprehensive investigation on how the decorporation agents CaNa3-DTPA (DTPA) and 3,4,3-LI(1,2-HOPO) (LIHOPO) affect EuIII interactions with human rat kidney cells in vitro. Cell biological investigations were complemented physicochemical measurements to correlate cytotoxic impairments intracellular metal uptake speciation. Upon exposure sole DTPA or LIHOPO, cell viability morphology are affected time- concentration-dependent manner. For both agents, detailed...
The interaction of the two chemical homologues [Cm(III) and Eu(III)] with calcium silicate hydrates (CSH phases) at pH 13.3 has been investigated in batch-type sorption studies using Eu(III) complemented time-resolved laser fluorescence spectroscopy (TRLFS) Cm(III). data for reveal fast kinetics a strong uptake by CSH phases distribution ratios (6 ± 3) × 105 L kg-1. Three different Cm(III) species have identified: A nonfluorescing species, which was identified as curium hydroxide (surface)...
The behavior of radionuclides in the environment (geo-, hydro-, and biosphere) is determined by interface reactions like adsorption, ion exchange, incorporation processes. Presently, operational gross parameters for distribution between solution minerals are available. For predictive modeling radionuclide mobility such systems, however, individual processes need to be localized, characterized, quantified. A prerequisite localization clarification concerned use modern advanced analytical...
Trivalent actinides and their lanthanide homologues are being scrutinized for potential health risk when ingested as a result of range industrial activities such mining. Importantly, these ions known to exhibit high affinity towards calmodulin (CaM). In case inadvertent uptake, the holoproteins that occupied by cations may block signal transduction pathways or increase concentration in intact cells, which could lead accumulation human organs. Accordingly, this investigation employed...
99Tc(VII) uptake by synthetic pure pyrite at 21 °C was studied in a wide pH range from 3.50 to 10.50 using batch experiments combined with scanning electron microscopy, X-ray absorption spectroscopy (XAS), photoelectron (XPS), and Raman microscopy. We found that removes Tc quantitatively solution (log Kd = 5.0 ± 0.1) within 1 day ≥ 5.50 0.08. At < 0.08, the process is slower, leading 98% removal 4.5 after 35 days. The slower explained higher solubility under acidic conditions. After 2 months...
To pursue the design of in vivo stable chelating systems for radiometals, a concise and straightforward method toolbox was developed combining NMR, isothermal titration calorimetry (ITC), europium time-resolved laser-induced fluorescence spectroscopy (Eu-TRLFS). For this purpose, macropa chelator chosen, Lu3+, La3+, Pb2+, Ra2+, Ba2+ were chosen as radiopharmaceutically relevant metal ions. They differ charge (2+ 3+) coordination properties (main group vs lanthanides). 1H NMR used to...
For long-term performance assessment of nuclear waste repositories knowledge concerning interactions actinides with mineral surfaces is imperative. The mobility and bioavailability released radionuclides strongly dependent on sorption/desorption processes onto surfaces. Therefore it necessary to characterize the surface species formed elucidate reaction mechanisms involved. high fluorescence spectroscopic sensitivity Cm(III) has attracted our interest regarding complexation process smectite...
Rock salt represents a potential host rock formation for the final disposal of radioactive waste. The interactions between indigenous microorganisms and radionuclides, e.g. uranium, need to be investigated better predict influence on safety assessment repository. Hence, association process uranium with two isolated from was comparatively studied. Brachybacterium sp. G1, which German dome Gorleben, Halobacterium noricense DSM15987T, were selected as examples moderately halophilic bacterium an...
For the first time, physiological and cellular responses of Nicotiana tabacum (BY-2) cells to uranium (U) as an abiotic stressor were studied using a multi-analytic approach that combined biochemical analysis, thermodynamic modeling spectroscopic studies. The goal this investigation was determine U threshold toxicity in tobacco BY-2 cells, influence on homeostasis micro-macro essential nutrients, well effect Fe starvation bioassociation cultured cells. Our findings demonstrated interferes...
The complex formation of Eu(III) and Cm(III) was studied via tetradentate, hexadentate, octadentate coordinating ligands the aminopolycarboxylate family, viz., nitrilotriacetate (NTA3-), ethylenediaminetetraacetate (EDTA4-), ethylene glycol-bis(2-aminoethyl ether)-N,N,N',N'-tetraacetate (EGTA4-), respectively. Based on complexones' pKa values obtained from 1H nuclear magnetic resonance (NMR) spectroscopic pH titration, constants were determined by means parallel-factor-analysis-assisted...