A5079177584- Radioactive element chemistry and processing
- Nuclear Materials and Properties
- Nuclear materials and radiation effects
- X-ray Diffraction in Crystallography
- Crystallization and Solubility Studies
- Selenium in Biological Systems
- Arsenic contamination and mitigation
- Geochemistry and Elemental Analysis
- Radioactive contamination and transfer
- Lanthanide and Transition Metal Complexes
- Advanced Polymer Synthesis and Characterization
- Nuclear Physics and Applications
- Iron oxide chemistry and applications
- Pickering emulsions and particle stabilization
- Radioactivity and Radon Measurements
- Chemical Synthesis and Characterization
- Catalytic Processes in Materials Science
- Coal and Its By-products
- Electrochemical Analysis and Applications
- Polymer Surface Interaction Studies
- Trace Elements in Health
- Heavy metals in environment
- Laser-Ablation Synthesis of Nanoparticles
- biodegradable polymer synthesis and properties
- Geochemistry and Geologic Mapping
Helmholtz-Zentrum Dresden-Rossendorf
2016-2025
Technische Universität Dresden
2020
European Synchrotron Radiation Facility
2019
University of Graz
2017
University of Bayreuth
2009-2014
Institute of Macromolecular Chemistry
2009
The origin of the organic layer covering colloidal biogenic elemental selenium nanoparticles (BioSeNPs) is not known, particularly in case when they are synthesized by complex microbial communities. This study investigated presence extracellular polymeric substances (EPS) on BioSeNPs. role EPS capping extracellularly available BioSeNPs was also examined. Fourier transform infrared (FT-IR) spectroscopy and colorimetric measurements confirmed functional groups characteristic proteins...
We report the preparation of water-soluble organo-silica hybrid nanotubes templated by core-shell-corona structured triblock terpolymer cylindrical polymer brushes (CPBs). The CPBs consist a polymethacrylate backbone, poly(tert-butyl acrylate) (PtBA) core, poly(3-(trimethoxysilyl)propyl (PAPTS) shell, and poly(oligo(ethylene glycol) methacrylate) (POEGMA) corona. They were prepared via "grafting from" strategy combination two living/controlled polymerization techniques: anionic for backbone...
The mechanism of selenium(IV) uptake by maghemite was investigated on both the macroscopic and molecular level. Maghemite nanoparticles exhibited fast adsorption kinetics toward selenium(IV). Batch experiments showed a decreased sorption with increasing pH (3.5-11). Ionic strength variations (0.01 to 0.1 M NaCl) had no significant influence uptake. Electrophoretic mobility measurements revealed shift lower values isoelectric point upon uptake, suggesting formation inner-sphere surface...
Previous spectroscopic research suggested that uranium(VI) adsorption to iron oxides is dominated by ternary uranyl−carbonato surface complexes across an unexpectedly wide pH range. Formation of such would have a significant impact on the sorption behavior and mobility uranium in aqueous environments. We therefore reinvestigated identity structural coordination uranyl using combination U LIII-edge extended X-ray absorption fine structure (EXAFS) spectroscopy iterative transformation factor...
Cerium(III) and cerium(IV) both form formate complexes. However, their species in aqueous solution the solid-state structures are surprisingly different. The solutions were investigated with Ce K-edge EXAFS spectroscopy. Ce(III) shows only mononuclear complexes, which is agreement predicted of Ce(HCOO)(2+) Ce(HCOO)2(+). In contrast, Ce(IV) forms a stable hexanuclear complex [Ce6(μ3-O)4(μ3-OH)4(HCOO)x(NO3)y](12-x-y). structural differences reflect different influence hydrolysis, weak for...
Complex formation and the coordination of zirconium with acetic acid were investigated Zr K-edge extended X-ray absorption fine structure spectroscopy (EXAFS) single-crystal diffraction. EXAFS spectra show that a stepwise increase in aqueous solution 0.1 M Zr(IV) leads to structural rearrangement from initial tetranuclear hydrolysis species [Zr4(OH)8(OH2)16]8+ hexanuclear acetate Zr6(O)4(OH)4(CH3COO)12. The Zr6(O)4(OH)4(CH3COO)12 was preserved crystals by slow evaporation solution....
Colloid formation and solubility of U(IV) in acidic HClO 4 /NaClO solutions are investigated by coulometric titration. Quantification traces U(VI) laser fluorescence spectroscopy proves that the tetravalent state uranium had been maintained. Laser-induced breakdown detection (LIBD) is applied for colloids as pH increased. The values at onset colloid used thermodynamic calculations aimed determining products K ° sp crystalline amorphous dioxides. particle size determined means LIBD taken into...
A hexanuclear Th(IV)-glycine complex was observed by Th L(3)-edge EXAFS measurements in an aqueous solution. Within the stability range of this positively charged species [Th(6)(μ(3)-O)(4)(μ(3)-OH)(4)(H(2)O)(6)(Gly)(6)(HGly)(6)](6+) preserved a crystal with composition [Th(6)(μ(3)-O)(4)(μ(3)-OH)(4)(H(2)O)(6)(Gly)(6)(HGly)(6)]·(NO(3))(3)(ClO(4))(3)(H(2)O)(3). This appears as result competing reaction between hydrolysis and ligation glycine. At pH value below complex, crystals...
Telechelic ("dumbbell-shaped") POSS-containing inorganic/organic hybrid poly(tert-butyl acrylate) (POSS-PtBA-POSS) was prepared by the combination of ATRP and copper-catalyzed azide–alkyne "click" reaction. bromoterminated PtBAs with different molecular weights were first via using a dibromo-functionalized initiator; subsequently, bromo groups transformed to azido sodium azide in DMF nucleophilic substitution. The coupling between azido-terminated PtBA alkyne-functionalized POSS successfully...
Abstract Here we provide evidence that the formation of PuO 2 nanoparticles from oxidized Pu VI under alkaline conditions proceeds through an intermediate V solid phase, similar to NH 4 CO 3 , which is stable over a period several months. For first time, state‐of‐the‐art experiments at M and L absorption edges combined with theoretical calculations unambiguously allow determine oxidation state local structure this phase.
We have constructed an unprecedented MOF platform that accommodates a range of 5f-block metal ions (Th4+, U4+, Np4+, Pu4+) as the primary building block. The isoreticular actinide metal-organic frameworks (An-MOFs) exhibit periodic trends in 12-coordinate environment, ligand configuration, and resulting ultramicroporosity. It holds potential distinguishing neighboring tetravalent actinides. ionic radius, carboxylate bite angle, anthracene plane twisting, interligand interactions,...
The nanoscience field often produces results more mystifying than any other discipline. It has been argued that changes in the plutonium dioxide (PuO2) particle size from bulk to nano can have a drastic effect on PuO2 properties. Here we report full characterization of nanoparticles (NPs) at atomic level and probe their local electronic structures by variety methods available synchrotron.
The significant interest in actinide bonding has recently focused on novel compounds with exotic oxidation states. However, the difficulty obtaining relevant high-quality experimental data, particularly for low-valent compounds, prevents a deeper understanding of 5f systems. Here we show X-ray absorption near-edge structure (XANES) measurements high-energy resolution fluorescence detection (HERFD) mode at uranium M
Well-defined core−shell bishydrophilic cylindrical polymer brushes (CPBs) with a poly(2-hydroxyethyl methacrylate) (PHEMA) core and poly(oligo(ethylene glycol) (POEGMA) shell were synthesized via the combination of anionic polymerization atom transfer radical polymerization. They used as unimolecular template for controlled fabrication linear assemblies titania nanoparticles. The precursors found localized mainly in brush transalcoholysis reaction partially weak complexation force. After...