Depleted uranium used as ammunition corrodes in the environment forming mineral phases and then dissolved uranium species like uranium carbonates (Schimmack et al., in Radiat Environ Biophys 46:221-227, 2007) and hydroxides. These hydroxide species were contacted with plant cells (canola). After 24 h contact time the cells were fractionated and the uranium speciation in the fraction was determined by time resolved laser-induced fluorescence spectroscopy at room temperature as well at 150 K. It could be shown that the uranium speciation in the fractions is different to that in the nutrient solution. Comparison of the emission bands with literature data allows assignment of the uranium binding forms.
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Inorg Chem
December 2024
State Key Laboratory for Mineral Deposits Research, School of Earth Sciences and Engineering, Nanjing University, Nanjing, Jiangsu 210023, China.
In this study, we employed classical molecular dynamics (CMD) and first-principles molecular dynamics (FPMD) simulations to investigate the speciation of uranyl in carbonate-rich hydrothermal solutions. The association constants (log) of uranyl carbonate complexes were derived from the potential of mean forces (PMFs) obtained from CMD simulations, and the acid constants (ps) of uranyl aqua ions were calculated using the FPMD-based vertical energy gap method. The results showed that uranyl ions could form stable mono- and bi-carbonate complexes at elevated temperatures and that uranyl aqua ions strongly hydrolyzed in neutral solutions at temperatures exceeding 473 K.
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November 2024
Pacific Northwest National Laboratory, 902 Battelle Boulevard, Richland, Washington 99352, United States.
Optical spectroscopy is a valuable tool for online monitoring of a variety of processes. Ultraviolet-visible (UV-vis) spectroscopy can monitor the concentration of analytes as well as identify the speciation and oxidation state. However, it can be difficult or impossible to employ UV-vis-based sensors in chemical systems that are very dark (i.
View Article and Find Full Text PDFChemosphere
November 2024
Institute for Advanced Membrane Technology (IAMT), Karlsruhe Institute of Technology (KIT), Hermann-von-Helmholtz-Platz 1, 76344, Eggenstein-Leopoldshafen, Germany. Electronic address:
Composite membranes incorporated with high-performance adsorbents are promising for uranium removal. The impact of speciation and ionic strength on uranium adsorption by zeolites was investigated in both static adsorption and composite membrane filtration. Zeolites with high Si/Al ratios exhibited the highest uranium adsorption capacity.
View Article and Find Full Text PDFAnal Chim Acta
November 2024
Departament de Química, Física i Ciències Ambientals i del Sòl, Universitat de Lleida and AGROTECNIO-CERCA, Rovira Roure 191, 25198, Lleida, Spain.
Background: In a context of environmental monitoring around installations related to the nuclear fuel cycle, the Diffusive Gradient in Thin-films (DGT) technique captures the integrated concentration of U isotopes in their native environment, yielding comprehensive data on U origin (anthropogenic vs natural), total concentration, and mobility. However, for common deployment times (4-5 days) in moderately basic waters, none of the commercially available binding gels is adapted to measure the total U concentration. So, the development of novel DGT binding gels is timely.
View Article and Find Full Text PDFSci Total Environ
December 2024
Helmholtz-Zentrum Dresden-Rossendorf, Institute of Resource Ecology, Dresden, Germany. Electronic address:
Microbial U(VI) reduction plays a major role in new bioremediation strategies for radionuclide-contaminated environments and can potentially affect the safe disposal of high-level radioactive waste in a deep geological repository. Desulfitobacterium sp. G1-2, isolated from a bentonite sample, was used to investigate its potential to reduce U(VI) in different background electrolytes: bicarbonate buffer, where a uranyl(VI)‑carbonate complex predominates, and synthetic Opalinus Clay pore water, where a uranyl(VI)-lactate complex occurs, as confirmed by time-resolved laser-induced fluorescence spectroscopic measurements.
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