A5043702852- Radioactive element chemistry and processing
- Crystallization and Solubility Studies
- X-ray Diffraction in Crystallography
- Nuclear Materials and Properties
- Radioactive contamination and transfer
- Geochemistry and Elemental Analysis
- Nuclear materials and radiation effects
- Chemical Synthesis and Characterization
- Metal-Organic Frameworks: Synthesis and Applications
- Nuclear reactor physics and engineering
- Crystal Structures and Properties
- Lanthanide and Transition Metal Complexes
- Analytical chemistry methods development
- Geochemistry and Geologic Mapping
- Catalytic Processes in Materials Science
- Iron oxide chemistry and applications
- Extraction and Separation Processes
- Polyoxometalates: Synthesis and Applications
- Zeolite Catalysis and Synthesis
- Nuclear and radioactivity studies
- Clay minerals and soil interactions
- Geological and Geochemical Analysis
- Electrochemical Analysis and Applications
- Minerals Flotation and Separation Techniques
- Coordination Chemistry and Organometallics
University of Notre Dame
2014-2025
Savannah River National Laboratory
2021
Notre Dame of Dadiangas University
2019
Clemson University
2010-2014
Piedmont University
2012
Robust and versatile metal–organic frameworks (MOFs) have emerged as sophisticated scaffolds to meet the critical needs of nuclear community, but their performance depends on underexplored structural integrities in high- radiation fields. The contributions selected metal nodes stability MOFs within isostructural M-UiO-66 series (where M = Zr, Ce, Hf, Th, Pu; Zr-UiO-66 experiments were executed a previous work) been determined. Ce-, Hf-, Th-UiO-66 MOF samples irradiated via gamma He-ion...
We report the synthesis and characterization of first plutonium metal–organic framework (MOF). Pu-UiO-66 expands established UiO-66 series, which includes transition metal, lanthanide, early actinide elements in hexanuclear nodes. The thermal stability porosity were experimentally determined, multifaceted computational methods used to corroborate experimental values, examine inherent defects framework, decipher spectroscopic signatures, elucidate electronic structure. crystallization a chain...
Crystallization at the solid-liquid interface is difficult to spectroscopically observe and therefore challenging understand ultimately control molecular level. The Ce70-torroid formulated [CeIV70(OH)36(O)64(SO4)60(H2O)10]4-, part of a larger emerging family MIV70-materials (M = Zr, U, Ce), presents such an opportunity. We elucidated assembly mechanisms by X-ray scattering (small-angle total scattering) solutions solids as well crystallizing identifying fragments Ce70 single-crystal...
We report the synthesis, characterization, and iodine capture application of a novel thorium-organic nanotube, TSN-626, [Th6O4(OH)4(C6H4NO2)7(CHO2)5(H2O)3]·3H2O. The classification as metal-organic nanotube (MONT) distinguishes it rare reduced dimensionality subset frameworks (MOFs); structure is additionally hallmarked by low node connectivity. TSN-626 composed hexameric thorium secondary building units mixed O/N-donor isonicotinate ligands that demonstrate selective ditopicity, yielding...
Nanoscale iron oxides (e.g., hematite (α-Fe2O3)) have unique properties, such as enhanced chemical reactivity and high surface area, when compared with their bulk counterparts. These nanoscale surfaces can be more reactive due to the presence of defects oxygen vacancies). In this work, we probed chemistry via X-ray photoelectron spectroscopy, electron microscopy, powder diffraction. Oxygen exposure vacuum annealing experiments were conducted add or remove vacancies adventitious carbon....
Abstract Plutonium(IV) oxide nanoclusters represent an interesting scientific problem regarding structure‐function relationships and are also relevant to global concerns surrounding plutonium reprocessing, the remediation of plutonium‐contaminated soils, storage or disposal plutonium‐containing wastes. Here we report synthesis five unique Pu IV containing 38, 22, 16 metal centers capped only with inorganic ligands, such as chlorine water, which prevent formation extended PuO 2 structure. The...
Abstract Plutonium subsurface mobility is primarily controlled by its oxidation state, which in turn loosely coupled to the state of iron system. Experiments were conducted examine effect sediment mineral composition and on plutonium sorption reduction. A pH 6.3 vadose zone containing oxides iron-containing phyllosilicates was treated with various complexants (ammonium oxalate) reductants (hydroxylamine hydrochloride dithionite-citrate-bicarbonate (DCB)) selectively leach and/or reduce oxide...
Changes in aqueous- and solid-phase plutonium oxidation states were monitored as a function of time concentration hematite (α-Fe2O3) suspensions containing initially Pu(V). Batch kinetic experiments conducted at concentrations between 10–8 10–6 M pH 5 0.3 g/L (9.3 m2/L) hematite. Surface-mediated reduction Pu(V) was observed under all conditions studied. However, differences the reaction kinetics demonstrate that mechanism changes concentration. Adsorption found to be rate-limiting step less...
Spent nuclear fuel (SNF) contains transuranic and lanthanide species, which are sometimes recovered repurposed. One particularly problematic fission product,
The presence of uranium-based nanomaterials in environmental systems may significantly impact our current understanding the fate and transport U(VI). Sorption uranyl peroxide nanocluster [(UO2)(O2)(OH)]6060– (U60) to hematite (α-Fe2O3) was studied using batch sorption experiments with varying U60, hematite, alkali electrolyte (i.e., NaCl, KCl, CsCl) concentrations. Data from electrospray ionization mass spectrometry centrifugal microfiltration revealed that U60 persisted background for at...
We report the synthesis and characterization of K4 {[PuCl2 (NO3 )3 ]2 (μ2 -O)}⋅H2 O, which contains first known μ2 -oxo bridge between two PuIV metal centers. Adding to its uniqueness is Pu-(μ2 -O) bond length 2.04 Å, shortest other analogous compounds. The -O)-Pu characterized by mixing s-, d-, p-orbitals from Pu with O; 5f-orbitals do not participate in bonding. Natural orbital analysis indicates that O interact through one 3c-2e σPu-O-Pu πPu-O-Pu bonding orbitals electron density highly...
Uranyl peroxide nanoclusters are an evolving family of materials with potential applications throughout the nuclear fuel cycle. While several studies have investigated their interactions alkali and alkaline earth metals, no probed actinide elements. This work describes a system containing U60 Ox30 , [((UO2 )(O2 ))60 (C2 O4 )30 ]60- neptunium(V) as function neptunium concentration. Ultra-small small angle X-ray scattering were used to observe these in aqueous phase, diffraction was solid...
Four unique actinide sulfates were synthesized using solvothermal techniques with strong acids. The first plutonium(III) sulfate structure, Pu(HSO4)3, was and is isostructural analogous lanthanide-based frameworks. A similar synthesis approach yielded crystals of NpNa0.5(HSO4)15(SO4)1.5, which has a comparable framework to the Pu(III) compound, but neptunium metal tetravalent sodium incorporated into as confirmed by chemical analysis. Anhydrous sulfate, Np(SO4)2, reported isotypic U(SO4)2....
Combined advanced spectroscopy and solubility studies provide evidence for the formation of novel calcium-containing hydrolyzed (Cm,Pu)( iii )–EDTA complex(es).
The unique properties of uranium-based nanomaterials may significantly impact our current understanding the fate and transport U(VI) in environmental systems. Sorption uranyl peroxide nanocluster [(UO2)(O2)(OH)]6060- (U60) to goethite (α-FeOOH) was studied using batch sorption experiments as a function U60 concentration (0.5–2 g·L–1), mineral (100–500 m2·L–1), pH (8–10). resulting rate law describing interactions with at 9 R = −krxn[U60]0.29±0.02[goethite]1.2±0.1 where krxn (6.7 ± 2.0) ×...