A5054098669- Radioactive element chemistry and processing
- Lanthanide and Transition Metal Complexes
- Chemical and Physical Properties in Aqueous Solutions
- Chemical Synthesis and Characterization
- Chemical Thermodynamics and Molecular Structure
- X-ray Diffraction in Crystallography
- Crystallization and Solubility Studies
- Analytical chemistry methods development
- Vanadium and Halogenation Chemistry
- Chemical Reaction Mechanisms
- Electrochemical Analysis and Applications
- Metal-Organic Frameworks: Synthesis and Applications
- Radioactive contamination and transfer
- Cancer, Hypoxia, and Metabolism
- Pigment Synthesis and Properties
- Electrochemical sensors and biosensors
- Carbon and Quantum Dots Applications
- Biochemical Acid Research Studies
- Bone and Dental Protein Studies
- Extraction and Separation Processes
- Covalent Organic Framework Applications
- Digestive system and related health
- Microbial Metabolic Engineering and Bioproduction
- Radiopharmaceutical Chemistry and Applications
- Advanced biosensing and bioanalysis techniques
Lawrence Berkeley National Laboratory
2002-2019
Washington State University
2002-2019
Berkeley College
2016-2018
Pacific Northwest National Laboratory
2002
This review provides a brief background on the extraction of uranium from seawater as well recent work by United States Department Energy this project. The world's oceans contain at 3 parts per billion, and despite low concentration, there has been historical interest in harvesting it, mainly Japan 1980s decade. Improvements materials, chemistry, deployment methods have all made, with ultimate goal lower cost. partially realized, dropping approximately $2000 kg U3O8 extracted 1984 to $500...
A non-oxido V(<sc>v</sc>) complex with glutaroimide-dioxime (H<sub>3</sub>L), a ligand for recovering uranium from seawater, was synthesized aqueous solution as Na[V(L)<sub>2</sub>]·2H<sub>2</sub>O, and the structure determined by X-ray diffraction.
Polyacrylonitrile (PAN) homopolymer and polyacrylonitrile-block-poly(n-butyl acrylate) (PAN-b-PBA) block copolymer were synthesized via supplemental activator reducing agent atom transfer radical polymerization used as precursors to nitrogen-doped nanocarbons. Carbonization was performed at two different temperatures (500 800 °C) fabricate nanocarbons with structural properties nitrogen contents. Copolymer-templated carbons (CTNCs) had larger surface area higher mesoporosity than PAN...
Carbon dots (CDs) possess abundant functional groups on their surface which are related to application in various fields such as sensing, imaging, and catalysis. Understanding the amount properties of these interaction with metal ions is essential but has posed longstanding challenges because diverse complex structures CDs. In this work, potentiometric titration demonstrated an effective method figure out categories amounts groups. Surface complexation modeling FITEQL program was applied...
Glutaroimide-dioxime forms strong complexes with tetravalent Th(iv) and Np(iv) in aqueous solution. In conjunction literature data on the complexation of glutaroimide-dioxime other metal ions, it was found that become weaker as effective charge density ions decreases: V5+ > Th4+ ≈ Fe3+ UO22+ Eu3+/Nd3+ Cu2+ Pb2+ NpO2+ Ca2+/Mg2+. Np(iv), deprotonation imide group relocation two hydrogen atoms from oxygen to nitrogen oxime groups result a large conjugated system (-O-N-C-N-C-N-O-) coordinates...
The use of amidoxime-functionalized polymer fibers as a sorbent for uranium has attracted recent interest the extraction from seawater. Vanadium is one main competing ions sorption V(v) species, however, vanadium also present V(iv) in In study, interactions with amidoxime and similar ligands were explored. Attempts made to synthesize complexes glutaroimide-dioxime, molecular analogue sorbents. However, was found react irreversibly glutaroimide-dioxime other oxime groups, oxidizing oxidation...
The stability constants (log β) of 1:1 uranyl complexes with three N,O-mixed donor ligands (L = 2,2'-dipyridyl-6,6'-dicarboxylate, 3,3'-dimethyl-2,2'-bipyridine-6,6'-dicarboxylate, and 1,10-phenanthroline-2,9-dicarboxylate, denoted as BiPDA, DmBiPDA, PhenDA, respectively) in aqueous DMSO/20%(v)H2O solutions were determined by spectrophotometry 0.1 M tetraethylammonium perchlorate. effects ligand preorganization, steric hindrance, solvation on the binding strength U(VI) discussed. In...
Hydrolysis of Th(iv) was studied in tetraethylammonium perchlorate (0.10 mol kg(-1)) at variable temperatures (283-358 K) by potentiometry and microcalorimetry. Three hydrolysis reactions, mTh(4+) + nH2O = Thm(OH)n((4m-n)+) nH(+), which (n,m) (2,2), (8,4), (15,6), were invoked to describe the potentiometric calorimetric data for solutions with [hydroxide]/[Th(iv)] ratio ≤ 2. At higher ratios, formation (16,5) cannot be excluded. The constants, *β2,2, *β8,4, *β15,6, increased 3, 7, 11 orders...
Complexation of V IV in aqueous solution with glutaroimide–dioxime (H 3 L), a ligand proposed for the possible sequestration uranium from seawater, was studied by combined application spectroscopic (EPR and UV/Vis), spectrometric (ESI‐MS), electrochemical (CV), computational (DFT) techniques. The results indicate that rare non‐oxido species, formula [V L 2 ] 2– , is formed pH range 3–5. It transforms into usual O complex, OL(OH)] at > 6. species characterized “ type ” EPR spectrum A z ≈...
N-(2-Hydroxyethyl)ethylenediamine-N,N′,N′-triacetic acid (HEDTA, denoted as H3L in this work, and the three dissociable protons represent those of carboxylic groups) is a strong chelating ligand plays an important role treatment disposal nuclear wastes well separation sciences f-elements. In complexation HEDTA with U(VI) was studied thermodynamically structurally aqueous solutions. Potentiometry microcalorimetry were used to measure constants (298–343 K) enthalpies (298 K), respectively, at...
Both macroscale and microscale methods to separate hydrolyzed Cr(III) species from acidic near-neutral pH solutions have been developed. The approach is based on ion exchange, involves separating monomeric, dimeric, trimeric, tetrameric, higher order oligomers such using a gradient elution with increasing cationic charge. With this approach, the concentration of given fraction can be maximized, complete resolution between these achieved. In addition, recovery column achievable. For capillary...
Complexation of Np(V) with three structurally related amine-functionalized diacetamide ligands, including 2,2'-azanediylbis( N, N'-dimethylacetamide) (ABDMA), 2,2'-(methylazanediyl)bis( (MABDMA), and 2,2'-(benzylazanediyl)bis( (BnABDMA), in aqueous solutions was investigated. The stability constants two successive complexes, namely, NpO2L+ NpO2L2+, where L stands for the were determined by absorption spectrophotometry. results suggest that corresponding complexes follow trend: MABDMA > ABDMA...
Thermodynamic properties of the complexation 2,2'-(trifluoroazanediyl)bis(N,N'-dimethylacetamide) (CF3ABDMA) with U(VI), Nd(III), and Np(V) have been studied in 1.0 M NaNO3 at 25 °C. Equilibrium constants were determined by potentiometry spectrophotometry. In comparison a series structurally related amine-bridged diacetamide ligands, including 2,2'-(benzylazanediyl)bis(N,N'-dimethylacetamide) (BnABDMA), 2,2'-azanediylbis(N,N'-dimethylacetamide) (ABDMA),...
N-(2-Hydroxyethyl)ethylenediamine-N,N′,N′-triacetic acid (HEDTA, denoted as H3L) is a strong chelating ligand that widely used in the separation of f elements relevant to nuclear fuel cycle. There much be known about structure and composition coordination sphere complexes HEDTA with lanthanides. The complexation light lanthanides (La3+, Nd3+, Eu3+) was investigated thermodynamically structurally aqueous solutions. Potentiometry microcalorimetry were performed acquire constants (25–70 °C)...
The complexation of Np(<sc>v</sc>) with HEDTA in aqueous solutions was investigated by spectrophotometry, microcalorimetry and EXAFS. Thermodynamic parameters were determined coordination modes also discussed.
Gluconate is a multidentate ligand and its complexation with actinides has received increasing attention because of existence in high level nuclear wastes as well waste repositories. In this work, the gluconate Th(IV) was studied deuterated water (D2O) by pD titrations magnetic resonance (NMR) spectroscopy. pCD range 2.0–4.6, (GD4–) forms two 1:1 complexes Th(IV), Th(GD3)2+ Th(GD2)+. Their stability constants were determined to be log β(D)101(−1) = 1.04 ± 0.12 for Th4+ + GD4– Th(GD3)3+ D+...