A5013135934- Radioactive element chemistry and processing
- Nuclear Materials and Properties
- Radioactive contamination and transfer
- Nuclear materials and radiation effects
- Geochemistry and Elemental Analysis
- Nanoparticles: synthesis and applications
- Rare-earth and actinide compounds
- Geochemistry and Geologic Mapping
- Thermal and Kinetic Analysis
- Extraction and Separation Processes
- Chemical Synthesis and Characterization
- Graphite, nuclear technology, radiation studies
- Lanthanide and Transition Metal Complexes
- Layered Double Hydroxides Synthesis and Applications
- Radioactivity and Radon Measurements
- Organometallic Complex Synthesis and Catalysis
- Nuclear and radioactivity studies
- Nanocluster Synthesis and Applications
- Atmospheric and Environmental Gas Dynamics
- Nanomaterials for catalytic reactions
- Magnetism in coordination complexes
University of Manchester
2018-2025
Karlsruhe Institute of Technology
2022-2025
The actinides possess a complex electronic structure, making their chemical and physical properties among the least understood in periodic table. Advanced spectroscopic tools, able to obtain deep insights into structure binding of actinides, are highly desirable. Here, we introduce two sensitive tools: one determines number localized 5f electrons on an actinide atom, another assesses covalent character actinide-ligand bonding. Both tools based multiplet present M4 edge core-to-core resonant...
Colloids present a challenge for nuclear decommissioning and disposal due to their potential mobilise radionuclides. Waste retrieval of storage ponds spent fuel silos radioactive waste at the Sellafield facility, UK, are high priorities. The particulates characterised here originate from facilities > 60 years old provide unique opportunity investigate long-term fate radionuclides in an aquatic, engineered environment. Radioactive effluents were obtained legacy pond using ultrafiltration,...
In the United Kingdom, decommissioning of legacy spent fuel storage facilities involves retrieval radioactive sludges that have formed as a result corrosion Magnox nuclear fuel. Retrieval may re-suspend colloidal fraction sludge, thereby potentially enhancing mobility radionuclides including uranium. The properties layered double hydroxide (LDH) phase hydrotalcite, key product corrosion, and its interactions with U(VI) are interest. This is because hydrotalcite potential transport vector for...
Lanthanides are widely assumed not to form covalent bonds due the localized nature of their 4f valence electrons. This work demonstrates that ionic bond Sm(II) with cyclononatetraenyl (η
Uranium is typically the most abundant radionuclide by mass in radioactive wastes and a significant component of effluent streams at nuclear facilities. Actinide(IV) (An(IV)) colloids formed via various pathways, including corrosion spent fuel, have potential to greatly enhance mobility poorly soluble An(IV) forms, uranium. This particularly important conditions relevant decommissioning facilities geological disposal waste. Previous studies suggested that silicate could stabilize U(IV)...
The role of Fe in the increased stability uranyl( v ) is clarified by using state art uranium metalorganic chemistry, advanced X-ray spectroscopic approaches and computations.
Metaschoepite is commonly found in U-contaminated environments and metaschoepite-bearing wastes may be managed via shallow or deep disposal. Understanding metaschoepite dissolution tracking the fate of any liberated U thus important. Here, discrete horizons (UO3·nH2O) particles were emplaced flowing sediment/groundwater columns representative UK Sellafield Ltd. site. The column systems either remained oxic became anoxic due to electron donor additions, sacrificed after 6- 12-months for...
Uranium is a risk-driving radionuclide in both radioactive waste disposal and contaminated land scenarios. In these environments, range of biogeochemical processes can occur, including sulfate reduction, which induce sulfidation iron (oxyhydr)oxide mineral phases. During sulfidation, labile U(VI) known to reduce relatively immobile U(IV); however, the detailed mechanisms changes U speciation during reactions are poorly constrained. Here, we performed highly controlled experiments at pH 7 9.5...
In the UK, decommissioning of legacy spent fuel storage facilities at Sellafield nuclear facility requires retrieval radioactive sludge resulting from Magnox corrosion. However, retrievals may enhance uranium mobility including via sorption radionuclide nanoparticles onto colloidal phases such as hydrotalcite (Mg4Al2(OH)16(CO3).4H2O). Hydrotalcite is a Mg-Al layered double hydroxide (LDH) which corrosion product cladding. Currently, there are paucity studies examining interactions between...
Summary Bimetallic nanoparticle catalysts have attracted considerable attention due to their unique chemical and physical properties. The ability of metal‐reducing bacteria produce highly catalytically active monometallic nanoparticles is well known; however, the properties catalytic activity bimetallic synthesized with these organisms not understood. Here, we report one‐pot biosynthesis Pd/Ag (bio‐Pd/Ag) Pd/Au (bio‐Pd/Au) using bacterium, Shewanella oneidensis , under mild conditions....
U(IV) mobility can be significantly enhanced by colloids in both engineered and natural environments. This is particularly relevant decommissioning clean-up of nuclear facilities, such as legacy fuel ponds silos at the Sellafield site, UK, long-term radioactive waste geodisposal. In this study, product metallic uranium (U) corrosion under anaerobic, alkaline conditions was characterised, interaction with silicate solutions investigated. The U metal consisted crystalline UO2 nanoparticles...
Spent nuclear fuel contains both uranium (U) and high yield fission products, including strontium-90 (90Sr), a key radioactive contaminant at facilities. Both U 90Sr will be present where spent has been processed, in storage ponds tanks. However, the interactions between Sr phases under ambient conditions are not well understood. Over pH range of 4-14, we investigate sorption behavior contact with two cycle relevant U(IV) phases: nano-uraninite (UO2) U(IV)-silicate nanoparticles. Nano-UO2 is...
The impact of temperature on a freshly precipitated ThO2(am, hyd) solid phase was investigated using combination undersaturation solubility experiments and multi-method approach for the characterization phase. XRD EXAFS confirm that ageing at T = 80°C promotes significant increase particle size crystallinity. TG-DTA XPS support process is accompanied by an important decrease in number hydration waters/hydroxide groups original amorphous Th(IV) hydrous oxide. However, while clear differences...