Chemistry › Inorganic Chemistry

Radioactive element chemistry and processing

Works Count: 128990

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Description

This cluster of papers focuses on the chemistry of actinide and lanthanide elements, particularly uranium, and their interactions with various materials and compounds. The topics covered include extraction, sorption, bioremediation, complexation, adsorption, and coordination chemistry related to actinides and lanthanides. The research also explores the environmental implications and practical applications of these chemical processes, especially in the context of nuclear waste management.

Keywords

Actinides; Uranium; Lanthanides; Extraction; Sorption; Bioremediation; Complexation; Adsorption; Nuclear Waste; Coordination Chemistry

1994 REPORT ON ZINNWALDITE ZW‐C ANALYSED BY NINETY‐TWO GIT‐IWG MEMBER‐LABORATORIES

1994-04-01

K. Govindaraju , Ivan Rubeška , Tomáš Paukert

Within a short period of one year (November 1992‐ October 1993), ninety‐two IWG‐Member laboratories have been able to characterize the chemical composition of a candidate reference sample, Zinnwaldite ZW‐C, a … Within a short period of one year (November 1992‐ October 1993), ninety‐two IWG‐Member laboratories have been able to characterize the chemical composition of a candidate reference sample, Zinnwaldite ZW‐C, a Li‐mica, reputed difficult to analyse because of its high contents of F and rare alkali elements and of the presence of refractory minerals. Thanks to the help of 163 analysts from the 92 laboratories, it has been possible to assign working values for 20 major and minor elements including the rare alkali elements and for 43 trace elements; all the working values receive the status of recommended values, except H20, C02, LOI, CI and S. It is, indeed, a rare success for such a difficult sample!

THE ISOTOPIC COMPOSITION OF REDUCED ORGANIC CARBON

1980-01-01

Peter Deines

Theory of Atomic Collisions

1956-01-01

H. S. W. Massey

Compilation of stable isotope fractionation factors of geochemical interest

1977-01-01

Irving Friedman , James R. O’Neil

Phase equilibrium relations of the common rock-forming oxides except water, by G Phase equilibrium relations of the common rock-forming oxides except water, by G

The Chemistry of the Actinide Elements

1986-01-01

Joseph Katz , Glenn T. Seaborg , Lester R. Morss

User's guide to PHREEQC (Version 2): A computer program for speciation, batch-reaction, one-dimensional transport, and inverse geochemical calculations

1999-01-01

David L. Parkhurst , C.A.J. Appelo

PHREEQC version 2 is a computer program written in the C programming language that is designed to perform a wide variety of low-temperature aqueous geochemical calculations. PHREEQC is based on … PHREEQC version 2 is a computer program written in the C programming language that is designed to perform a wide variety of low-temperature aqueous geochemical calculations. PHREEQC is based on an ion-association aqueous model and has capabilities for (1) speciation and saturation-index calculations; (2) batch-reaction and one-dimensional (1D) transport calculations involving reversible reactions, which include aqueous, mineral, gas, solid-solution, surface-complexation, and ion-exchange equilibria, and irreversible reactions, which include specified mole transfers of reactants, kinetically controlled reactions, mixing of solutions, and temperature changes; and (3) inverse modeling, which finds sets of mineral and gas mole transfers that account for differences in composition between waters, within specified compositional uncertainty limits.New features in PHREEQC version 2 relative to version 1 include capabilities to simulate dispersion (or diffusion) and stagnant zones in 1D-transport calculations, to model kinetic reactions with user-defined rate expressions, to model the formation or dissolution of ideal, multicomponent or nonideal, binary solid solutions, to model fixed-volume gas phases in addition to fixed-pressure gas phases, to allow the number of surface or exchange sites to vary with the dissolution or precipitation of minerals or kinetic reactants, to include isotope mole balances in inverse modeling calculations, to automatically use multiple sets of convergence parameters, to print user-defined quantities to the primary output file and (or) to a file suitable for importation into a spreadsheet, and to define solution compositions in a format more compatible with spreadsheet programs. This report presents the equations that are the basis for chemical equilibrium, kinetic, transport, and inverse-modeling calculations in PHREEQC; describes the input for the program; and presents examples that demonstrate most of the program's capabilities.

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The Chemistry of the Actinide and Transactinide Elements

2006-01-01

Lester R. Morss , Norman M. Edelstein , J. Fuger

Geobacter sulfurreducens sp. nov., a hydrogen- and acetate-oxidizing dissimilatory metal-reducing microorganism

1994-10-01

Frank Caccavo , Debra J. Lonergan , Derek R. Lovley +3 more

A dissimilatory metal- and sulfur-reducing microorganism was isolated from surface sediments of a hydrocarbon-contaminated ditch in Norman, Okla. The isolate, which was designated strain PCA, was an obligately anaerobic, nonfermentative … A dissimilatory metal- and sulfur-reducing microorganism was isolated from surface sediments of a hydrocarbon-contaminated ditch in Norman, Okla. The isolate, which was designated strain PCA, was an obligately anaerobic, nonfermentative nonmotile, gram-negative rod. PCA grew in a defined medium with acetate as an electron donor and ferric PPi, ferric oxyhydroxide, ferric citrate, elemental sulfur, Co(III)-EDTA, fumarate, or malate as the sole electron acceptor. PCA also coupled the oxidation of hydrogen to the reduction of Fe(III) but did not reduce Fe(III) with sulfur, glucose, lactate, fumarate, propionate, butyrate, isobutyrate, isovalerate, succinate, yeast extract, phenol, benzoate, ethanol, propanol, or butanol as an electron donor. PCA did not reduce oxygen, Mn(IV), U(VI), nitrate, sulfate, sulfite, or thiosulfate with acetate as the electron donor. Cell suspensions of PCA exhibited dithionite-reduced minus air-oxidized difference spectra which were characteristic of c-type cytochromes. Phylogenetic analysis of the 16S rRNA sequence placed PCA in the delta subgroup of the proteobacteria. Its closest known relative is Geobacter metallireducens. The ability to utilize either hydrogen or acetate as the sole electron donor for Fe(III) reduction makes strain PCA a unique addition to the relatively small group of respiratory metal-reducing microorganisms available in pure culture. A new species name, Geobacter sulfurreducens, is proposed.

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Rare-earth element mobility during hydrothermal and metamorphic fluid-rock interaction and the significance of the oxidation state of europium

1991-12-01

Michael Bau

Lanthanides in organic chemistry. 1. Selective 1,2 reductions of conjugated ketones

1978-03-01

Jean Louis Luche

ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTLanthanides in organic chemistry. 1. Selective 1,2 reductions of conjugated ketonesJean Louis LucheCite this: J. Am. Chem. Soc. 1978, 100, 7, 2226–2227Publication Date (Print):March 1, 1978Publication History … ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTLanthanides in organic chemistry. 1. Selective 1,2 reductions of conjugated ketonesJean Louis LucheCite this: J. Am. Chem. Soc. 1978, 100, 7, 2226–2227Publication Date (Print):March 1, 1978Publication History Published online1 May 2002Published inissue 1 March 1978https://pubs.acs.org/doi/10.1021/ja00475a040https://doi.org/10.1021/ja00475a040research-articleACS PublicationsRequest reuse permissionsArticle Views12507Altmetric-Citations1090LEARN ABOUT THESE METRICSArticle Views are the COUNTER-compliant sum of full text article downloads since November 2008 (both PDF and HTML) across all institutions and individuals. These metrics are regularly updated to reflect usage leading up to the last few days.Citations are the number of other articles citing this article, calculated by Crossref and updated daily. Find more information about Crossref citation counts.The Altmetric Attention Score is a quantitative measure of the attention that a research article has received online. Clicking on the donut icon will load a page at altmetric.com with additional details about the score and the social media presence for the given article. Find more information on the Altmetric Attention Score and how the score is calculated. Share Add toView InAdd Full Text with ReferenceAdd Description ExportRISCitationCitation and abstractCitation and referencesMore Options Share onFacebookTwitterWechatLinked InRedditEmail Other access optionsGet e-Alertsclose Get e-Alerts

Self-consistent molecular orbital methods. 24. Supplemented small split-valence basis sets for second-row elements

1982-09-01

William J. Pietro , Michelle Francl , Warren J. Hehre +3 more

ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTSelf-consistent molecular orbital methods. 24. Supplemented small split-valence basis sets for second-row elementsW. J. Pietro, M. M. Francl, W. J. Hehre, D. J. DeFrees, J. A. Pople, … ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTSelf-consistent molecular orbital methods. 24. Supplemented small split-valence basis sets for second-row elementsW. J. Pietro, M. M. Francl, W. J. Hehre, D. J. DeFrees, J. A. Pople, and J. S. BinkleyCite this: J. Am. Chem. Soc. 1982, 104, 19, 5039–5048Publication Date (Print):September 1, 1982Publication History Published online1 May 2002Published inissue 1 September 1982https://pubs.acs.org/doi/10.1021/ja00383a007https://doi.org/10.1021/ja00383a007research-articleACS PublicationsRequest reuse permissionsArticle Views775Altmetric-Citations1057LEARN ABOUT THESE METRICSArticle Views are the COUNTER-compliant sum of full text article downloads since November 2008 (both PDF and HTML) across all institutions and individuals. These metrics are regularly updated to reflect usage leading up to the last few days.Citations are the number of other articles citing this article, calculated by Crossref and updated daily. Find more information about Crossref citation counts.The Altmetric Attention Score is a quantitative measure of the attention that a research article has received online. Clicking on the donut icon will load a page at altmetric.com with additional details about the score and the social media presence for the given article. Find more information on the Altmetric Attention Score and how the score is calculated. Share Add toView InAdd Full Text with ReferenceAdd Description ExportRISCitationCitation and abstractCitation and referencesMore Options Share onFacebookTwitterWechatLinked InRedditEmail Other access optionsGet e-Alertsclose Get e-Alerts

Microbial reduction of uranium

1991-04-01

Derek R. Lovley , Elizabeth J. Phillips , Yuri A. Gorby +1 more

Uranium solution-mineral equilibria at low temperatures with applications to sedimentary ore deposits

1978-06-01

Donald Langmuir

On statistical models for fission track counts

1981-12-01

R. F. Galbraith

Theoretical Studies on Reactions of Transition-Metal Complexes

2000-01-26

Shuqiang Niu , Michael B. Hall

ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTTheoretical Studies on Reactions of Transition-Metal ComplexesShuqiang Niu and Michael B. HallView Author Information Department of Chemistry, Texas A&M University, College Station, Texas 77843 Cite this: Chem. … ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTTheoretical Studies on Reactions of Transition-Metal ComplexesShuqiang Niu and Michael B. HallView Author Information Department of Chemistry, Texas A&M University, College Station, Texas 77843 Cite this: Chem. Rev. 2000, 100, 2, 353–406Publication Date (Web):January 26, 2000Publication History Received21 September 1999Published online26 January 2000Published inissue 1 February 2000https://pubs.acs.org/doi/10.1021/cr980404yhttps://doi.org/10.1021/cr980404yresearch-articleACS PublicationsCopyright © 2000 American Chemical SocietyRequest reuse permissionsArticle Views7823Altmetric-Citations806LEARN ABOUT THESE METRICSArticle Views are the COUNTER-compliant sum of full text article downloads since November 2008 (both PDF and HTML) across all institutions and individuals. These metrics are regularly updated to reflect usage leading up to the last few days.Citations are the number of other articles citing this article, calculated by Crossref and updated daily. Find more information about Crossref citation counts.The Altmetric Attention Score is a quantitative measure of the attention that a research article has received online. Clicking on the donut icon will load a page at altmetric.com with additional details about the score and the social media presence for the given article. Find more information on the Altmetric Attention Score and how the score is calculated. Share Add toView InAdd Full Text with ReferenceAdd Description ExportRISCitationCitation and abstractCitation and referencesMore Options Share onFacebookTwitterWechatLinked InRedditEmail Other access optionsGet e-Alertsclose SUBJECTS:Chemical reactions,Hydrocarbons,Ligands,Metals,Transition metals Get e-Alerts

Carius Tube Digestion for Low-Blank Rhenium-Osmium Analysis

1995-07-01

Steven B. Shirey , R. J. Walker

ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTCarius Tube Digestion for Low-Blank Rhenium-Osmium AnalysisSteven B. Shirey and Richard J. WalkerCite this: Anal. Chem. 1995, 67, 13, 2136–2141Publication Date (Print):July 1, 1995Publication History Published online1 … ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTCarius Tube Digestion for Low-Blank Rhenium-Osmium AnalysisSteven B. Shirey and Richard J. WalkerCite this: Anal. Chem. 1995, 67, 13, 2136–2141Publication Date (Print):July 1, 1995Publication History Published online1 May 2002Published inissue 1 July 1995https://pubs.acs.org/doi/10.1021/ac00109a036https://doi.org/10.1021/ac00109a036research-articleACS PublicationsRequest reuse permissionsArticle Views1281Altmetric-Citations730LEARN ABOUT THESE METRICSArticle Views are the COUNTER-compliant sum of full text article downloads since November 2008 (both PDF and HTML) across all institutions and individuals. These metrics are regularly updated to reflect usage leading up to the last few days.Citations are the number of other articles citing this article, calculated by Crossref and updated daily. Find more information about Crossref citation counts.The Altmetric Attention Score is a quantitative measure of the attention that a research article has received online. Clicking on the donut icon will load a page at altmetric.com with additional details about the score and the social media presence for the given article. Find more information on the Altmetric Attention Score and how the score is calculated. Share Add toView InAdd Full Text with ReferenceAdd Description ExportRISCitationCitation and abstractCitation and referencesMore Options Share onFacebookTwitterWechatLinked InRedditEmail Other access optionsGet e-Alertsclose Get e-Alerts

Uranium(VI) adsorption to ferrihydrite: Application of a surface complexation model

1994-12-01

T. David Waite , James A. Davis , Timothy E. Payne +2 more

"Heavy metals" a meaningless term? (IUPAC Technical Report)

2002-01-01

John H. Duffus

Abstract Over the past two decades, the term "heavy metals" has been widely used. It is often used as a group name for metals and semimetals (metalloids) that have been … Abstract Over the past two decades, the term "heavy metals" has been widely used. It is often used as a group name for metals and semimetals (metalloids) that have been associated with contamination and potential toxicity or ecotoxicity. At the same time, legal regulations often specify a list of "heavy metals" to which they apply. Such lists differ from one set of regulations to another and the term is sometimes used without even specifying which "heavy metals" are covered. However, there is no authoritative definition to be found in the relevant literature. There is a tendency, unsupported by the facts, to assume that all so-called "heavy metals" and their compounds have highly toxic or ecotoxic properties. This has no basis in chemical or toxicological data. Thus, the term "heavy metals" is both meaningless and misleading. Even the term "metal" is commonly misused in both toxicological literature and in legislation to mean the pure metal and all the chemical species in which it may exist. This usage implies that the pure metal and all its compounds have the same physicochemical, biological, and toxicological properties, which is untrue. In order to avoid the use of the term "heavy metal", a new classification based on the periodic table is needed. Such a classification should reflect our understanding of the chemical basis of toxicity and allow toxic effects to be predicted.

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Geomycology: biogeochemical transformations of rocks, minerals, metals and radionuclides by fungi, bioweathering and bioremediation

2007-01-01

Geoffrey Michael Gadd

Mechanism of molybdenum removal from the sea and its concentration in black shales: EXAFS evidence

1996-10-01

George R. Helz , Cherie V. Miller , John Charnock +4 more

Empirical parameters for calculating cation–oxygen bond valences

1976-07-01

I. D. Brown , Ke-Chen Wu

Fully optimized contracted Gaussian basis sets of triple zeta valence quality for atoms Li to Kr

1994-04-15

Ansgar Schäfer , Christian Huber , Reinhart Ahlrichs

Contracted Gaussian basis sets of triple zeta valence (TZV) quality are presented for Li to Kr. The TZV bases are characterized by typically including a single contraction to describe inner … Contracted Gaussian basis sets of triple zeta valence (TZV) quality are presented for Li to Kr. The TZV bases are characterized by typically including a single contraction to describe inner shells and three basis functions for valence shells. All parameters—orbital exponents and contraction coefficients—have been determined by minimization of atomic self-consistent field ground state energies. Advantages and necessary modifications of TZV basis sets are discussed for simple test calculations of molecular energies and nuclear magnetic resonance (NMR) chemical shieldings in treatments with and without inclusion of electron correlation.

Orbital interactions in metal dimer complexes

1975-08-01

P. Jeffrey Hay , Jack C. Thibeault , Roald Hoffmann

ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTOrbital interactions in metal dimer complexesP. Jeffrey Hay, Jack C. Thibeault, and Roald HoffmannCite this: J. Am. Chem. Soc. 1975, 97, 17, 4884–4899Publication Date (Print):August 1, 1975Publication … ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTOrbital interactions in metal dimer complexesP. Jeffrey Hay, Jack C. Thibeault, and Roald HoffmannCite this: J. Am. Chem. Soc. 1975, 97, 17, 4884–4899Publication Date (Print):August 1, 1975Publication History Published online1 May 2002Published inissue 1 August 1975https://pubs.acs.org/doi/10.1021/ja00850a018https://doi.org/10.1021/ja00850a018research-articleACS PublicationsRequest reuse permissionsArticle Views3486Altmetric-Citations1201LEARN ABOUT THESE METRICSArticle Views are the COUNTER-compliant sum of full text article downloads since November 2008 (both PDF and HTML) across all institutions and individuals. These metrics are regularly updated to reflect usage leading up to the last few days.Citations are the number of other articles citing this article, calculated by Crossref and updated daily. Find more information about Crossref citation counts.The Altmetric Attention Score is a quantitative measure of the attention that a research article has received online. Clicking on the donut icon will load a page at altmetric.com with additional details about the score and the social media presence for the given article. Find more information on the Altmetric Attention Score and how the score is calculated. Share Add toView InAdd Full Text with ReferenceAdd Description ExportRISCitationCitation and abstractCitation and referencesMore Options Share onFacebookTwitterWechatLinked InRedditEmail Other access optionsGet e-Alertsclose Get e-Alerts

Sequential separation of light rare-earth elements, thorium and uranium by miniaturized extraction chromatography: Application to isotopic analyses of silicate rocks

1997-02-01

Christian Pin , JoséFrancisco Santos Zalduegui

Self-consistent molecular orbital methods. 21. Small split-valence basis sets for first-row elements

1980-01-01

J. Stephen Binkley , John A. Pople , Warren J. Hehre

ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTSelf-consistent molecular orbital methods. 21. Small split-valence basis sets for first-row elementsJ. Stephen Binkley, John A. Pople, and Warren J. HehreCite this: J. Am. Chem. Soc. 1980, … ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTSelf-consistent molecular orbital methods. 21. Small split-valence basis sets for first-row elementsJ. Stephen Binkley, John A. Pople, and Warren J. HehreCite this: J. Am. Chem. Soc. 1980, 102, 3, 939–947Publication Date (Print):January 1, 1980Publication History Published online1 May 2002Published inissue 1 January 1980https://pubs.acs.org/doi/10.1021/ja00523a008https://doi.org/10.1021/ja00523a008research-articleACS PublicationsRequest reuse permissionsArticle Views3442Altmetric-Citations3561LEARN ABOUT THESE METRICSArticle Views are the COUNTER-compliant sum of full text article downloads since November 2008 (both PDF and HTML) across all institutions and individuals. These metrics are regularly updated to reflect usage leading up to the last few days.Citations are the number of other articles citing this article, calculated by Crossref and updated daily. Find more information about Crossref citation counts.The Altmetric Attention Score is a quantitative measure of the attention that a research article has received online. Clicking on the donut icon will load a page at altmetric.com with additional details about the score and the social media presence for the given article. Find more information on the Altmetric Attention Score and how the score is calculated. Share Add toView InAdd Full Text with ReferenceAdd Description ExportRISCitationCitation and abstractCitation and referencesMore Options Share onFacebookTwitterWechatLinked InRedditEmail Other access optionsGet e-Alertsclose Get e-Alerts

AMoRe: an automated package for molecular replacement

1994-03-01

Jorge Navaza

A new molecular-replacement package is presented. It is an improvement on conventional methods, based on more powerful algorithms and a new conception that enables automation and rapid solution. A new molecular-replacement package is presented. It is an improvement on conventional methods, based on more powerful algorithms and a new conception that enables automation and rapid solution.

Handbook of Basic Atomic Spectroscopic Data

2005-09-28

J. E. Sansonetti , William C. Martin

Energy-adjusted pseudopotentials for the actinides. Parameter sets and test calculations for thorium and thorium monoxide

1994-05-15

W. Küchle , Michael Dolg , Hermann Stoll +1 more

We present nonrelativistic and quasirelativistic energy-adjusted pseudopotentials, the latter augmented by spin–orbit operators, as well as optimized (12s11p10d8f)/ [8s7p6d4f]-Gaussian-type orbitals (GTO) valence basis sets for the actinide elements actinium through … We present nonrelativistic and quasirelativistic energy-adjusted pseudopotentials, the latter augmented by spin–orbit operators, as well as optimized (12s11p10d8f)/ [8s7p6d4f]-Gaussian-type orbitals (GTO) valence basis sets for the actinide elements actinium through lawrencium. Atomic excitation and ionization energies obtained by the use of these pseudopotentials and basis sets in self-consistent field (SCF) calculations differ by less than 0.2 eV from corresponding finite-difference all-electron results. Large-scale multiconfiguration self-consistent field (MCSCF), multireference configuration interaction (MRCI), and multireference averaged coupled-pair functional (MRACPF) calculations for thorium and thorium monoxide yield results in satisfactory agreement with available experimental data. Preliminary results from spin–orbit configuration interaction calculations for the low-lying electronic states of thorium monoxide are also reported.

Stimulating the In Situ Activity of Geobacter Species To Remove Uranium from the Groundwater of a Uranium-Contaminated Aquifer

2003-10-01

Robert Anderson , Helen A. Vrionis , Irene Ortiz-Bernad +7 more

ABSTRACT The potential for removing uranium from contaminated groundwater by stimulating the in situ activity of dissimilatory metal-reducing microorganisms was evaluated in a uranium-contaminated aquifer located in Rifle, Colo. Acetate … ABSTRACT The potential for removing uranium from contaminated groundwater by stimulating the in situ activity of dissimilatory metal-reducing microorganisms was evaluated in a uranium-contaminated aquifer located in Rifle, Colo. Acetate (1 to 3 mM) was injected into the subsurface over a 3-month period via an injection gallery composed of 20 injection wells, which was installed upgradient from a series of 15 monitoring wells. U(VI) concentrations decreased in as little as 9 days after acetate injection was initiated, and within 50 days uranium had declined below the prescribed treatment level of 0.18 μM in some of the monitoring wells. Analysis of 16S ribosomal DNA (rDNA) sequences and phospholipid fatty acid profiles demonstrated that the initial loss of uranium from the groundwater was associated with an enrichment of Geobacter species in the treatment zone. Fe(II) in the groundwater also increased during this period, suggesting that U(VI) reduction was coincident with Fe(III) reduction. As the acetate injection continued over 50 days there was a loss of sulfate from the groundwater and an accumulation of sulfide and the composition of the microbial community changed. Organisms with 16S rDNA sequences most closely related to those of sulfate reducers became predominant, and Geobacter species became a minor component of the community. This apparent switch from Fe(III) reduction to sulfate reduction as the terminal electron accepting process for the oxidation of the injected acetate was associated with an increase in uranium concentration in the groundwater. These results demonstrate that in situ bioremediation of uranium-contaminated groundwater is feasible but suggest that the strategy should be optimized to better maintain long-term activity of Geobacter species.

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Biogeochemical Redox Processes and their Impact on Contaminant Dynamics

2009-12-14

Thomas Borch , Ruben Kretzschmar , Andreas Kappler +4 more

Life and element cycling on Earth is directly related to electron transfer (or redox) reactions. An understanding of biogeochemical redox processes is crucial for predicting and protecting environmental health and … Life and element cycling on Earth is directly related to electron transfer (or redox) reactions. An understanding of biogeochemical redox processes is crucial for predicting and protecting environmental health and can provide new opportunities for engineered remediation strategies. Energy can be released and stored by means of redox reactions via the oxidation of labile organic carbon or inorganic compounds (electron donors) by microorganisms coupled to the reduction of electron acceptors including humic substances, iron-bearing minerals, transition metals, metalloids, and actinides. Environmental redox processes play key roles in the formation and dissolution of mineral phases. Redox cycling of naturally occurring trace elements and their host minerals often controls the release or sequestration of inorganic contaminants. Redox processes control the chemical speciation, bioavailability, toxicity, and mobility of many major and trace elements including Fe, Mn, C, P, N, S, Cr, Cu, Co, As, Sb, Se, Hg, Tc, and U. Redox-active humic substances and mineral surfaces can catalyze the redox transformation and degradation of organic contaminants. In this review article, we highlight recent advances in our understanding of biogeochemical redox processes and their impact on contaminant fate and transport, including future research needs.

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Dissimilatory Fe(III) and Mn(IV) reduction

1991-06-01

Derek R. Lovley

The oxidation of organic matter coupled to the reduction of Fe(III) or Mn(IV) is one of the most important biogeochemical reactions in aquatic sediments, soils, and groundwater. This process, which … The oxidation of organic matter coupled to the reduction of Fe(III) or Mn(IV) is one of the most important biogeochemical reactions in aquatic sediments, soils, and groundwater. This process, which may have been the first globally significant mechanism for the oxidation of organic matter to carbon dioxide, plays an important role in the oxidation of natural and contaminant organic compounds in a variety of environments and contributes to other phenomena of widespread significance such as the release of metals and nutrients into water supplies, the magnetization of sediments, and the corrosion of metal. Until recently, much of the Fe(III) and Mn(IV) reduction in sedimentary environments was considered to be the result of nonenzymatic processes. However, microorganisms which can effectively couple the oxidation of organic compounds to the reduction of Fe(III) or Mn(IV) have recently been discovered. With Fe(III) or Mn(IV) as the sole electron acceptor, these organisms can completely oxidize fatty acids, hydrogen, or a variety of monoaromatic compounds. This metabolism provides energy to support growth. Sugars and amino acids can be completely oxidized by the cooperative activity of fermentative microorganisms and hydrogen- and fatty-acid-oxidizing Fe(III) and Mn(IV) reducers. This provides a microbial mechanism for the oxidation of the complex assemblage of sedimentary organic matter in Fe(III)- or Mn(IV)-reducing environments. The available evidence indicates that this enzymatic reduction of Fe(III) or Mn(IV) accounts for most of the oxidation of organic matter coupled to reduction of Fe(III) and Mn(IV) in sedimentary environments. Little is known about the diversity and ecology of the microorganisms responsible for Fe(III) and Mn(IV) reduction, and only preliminary studies have been conducted on the physiology and biochemistry of this process.

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Geochemical approaches to sedimentation, provenance, and tectonics

1993-01-01

S. M. McLennan , Sidney R. Hemming , Diane K. McDaniel +1 more

THE PRINCIPLES DETERMINING THE STRUCTURE OF COMPLEX IONIC CRYSTALS

1929-04-01

Linus Pauling

ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTTHE PRINCIPLES DETERMINING THE STRUCTURE OF COMPLEX IONIC CRYSTALSLinus PaulingCite this: J. Am. Chem. Soc. 1929, 51, 4, 1010–1026Publication Date (Print):April 1, 1929Publication History Published online1 May … ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTTHE PRINCIPLES DETERMINING THE STRUCTURE OF COMPLEX IONIC CRYSTALSLinus PaulingCite this: J. Am. Chem. Soc. 1929, 51, 4, 1010–1026Publication Date (Print):April 1, 1929Publication History Published online1 May 2002Published inissue 1 April 1929https://pubs.acs.org/doi/10.1021/ja01379a006https://doi.org/10.1021/ja01379a006research-articleACS PublicationsRequest reuse permissionsArticle Views7079Altmetric-Citations1470LEARN ABOUT THESE METRICSArticle Views are the COUNTER-compliant sum of full text article downloads since November 2008 (both PDF and HTML) across all institutions and individuals. These metrics are regularly updated to reflect usage leading up to the last few days.Citations are the number of other articles citing this article, calculated by Crossref and updated daily. Find more information about Crossref citation counts.The Altmetric Attention Score is a quantitative measure of the attention that a research article has received online. Clicking on the donut icon will load a page at altmetric.com with additional details about the score and the social media presence for the given article. Find more information on the Altmetric Attention Score and how the score is calculated. Share Add toView InAdd Full Text with ReferenceAdd Description ExportRISCitationCitation and abstractCitation and referencesMore Options Share onFacebookTwitterWechatLinked InRedditEmail Other access optionsGet e-Alertsclose Get e-Alerts

Formation and properties of iron titanium hydride

1974-01-01

J.J. Reilly , R.H. Wiswall

ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTFormation and properties of iron titanium hydrideJ. J. Reilly and R. H. WiswallCite this: Inorg. Chem. 1974, 13, 1, 218–222Publication Date (Print):January 1, 1974Publication History Published online1 … ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTFormation and properties of iron titanium hydrideJ. J. Reilly and R. H. WiswallCite this: Inorg. Chem. 1974, 13, 1, 218–222Publication Date (Print):January 1, 1974Publication History Published online1 May 2002Published inissue 1 January 1974https://pubs.acs.org/doi/10.1021/ic50131a042https://doi.org/10.1021/ic50131a042research-articleACS PublicationsRequest reuse permissionsArticle Views2830Altmetric-Citations681LEARN ABOUT THESE METRICSArticle Views are the COUNTER-compliant sum of full text article downloads since November 2008 (both PDF and HTML) across all institutions and individuals. These metrics are regularly updated to reflect usage leading up to the last few days.Citations are the number of other articles citing this article, calculated by Crossref and updated daily. Find more information about Crossref citation counts.The Altmetric Attention Score is a quantitative measure of the attention that a research article has received online. Clicking on the donut icon will load a page at altmetric.com with additional details about the score and the social media presence for the given article. Find more information on the Altmetric Attention Score and how the score is calculated. Share Add toView InAdd Full Text with ReferenceAdd Description ExportRISCitationCitation and abstractCitation and referencesMore Options Share onFacebookTwitterWechatLinked InRedditEmail Other access optionsGet e-Alertsclose Get e-Alerts

Deuterium-isotope Effects in the Autoxidation of Aralkyl Hydrocarbons. Mechanism of the Interaction of PEroxy Radicals1

1957-07-01

Glen A. Russell

ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTDeuterium-isotope Effects in the Autoxidation of Aralkyl Hydrocarbons. Mechanism of the Interaction of PEroxy Radicals1Glen A. RussellCite this: J. Am. Chem. Soc. 1957, 79, 14, 3871–3877Publication Date … ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTDeuterium-isotope Effects in the Autoxidation of Aralkyl Hydrocarbons. Mechanism of the Interaction of PEroxy Radicals1Glen A. RussellCite this: J. Am. Chem. Soc. 1957, 79, 14, 3871–3877Publication Date (Print):July 1, 1957Publication History Published online1 May 2002Published inissue 1 July 1957https://pubs.acs.org/doi/10.1021/ja01571a068https://doi.org/10.1021/ja01571a068research-articleACS PublicationsRequest reuse permissionsArticle Views2315Altmetric-Citations962LEARN ABOUT THESE METRICSArticle Views are the COUNTER-compliant sum of full text article downloads since November 2008 (both PDF and HTML) across all institutions and individuals. These metrics are regularly updated to reflect usage leading up to the last few days.Citations are the number of other articles citing this article, calculated by Crossref and updated daily. Find more information about Crossref citation counts.The Altmetric Attention Score is a quantitative measure of the attention that a research article has received online. Clicking on the donut icon will load a page at altmetric.com with additional details about the score and the social media presence for the given article. Find more information on the Altmetric Attention Score and how the score is calculated. Share Add toView InAdd Full Text with ReferenceAdd Description ExportRISCitationCitation and abstractCitation and referencesMore Options Share onFacebookTwitterWechatLinked InRedditEmail Other access optionsGet e-Alertsclose Get e-Alerts

Materials for the Recovery of Uranium from Seawater

2017-11-22

Carter W. Abney , Richard T. Mayes , Tomonori Saito +1 more

More than 1000× uranium exists in the oceans than exists in terrestrial ores. With nuclear power generation expected to increase over the coming decades, access to this unconventional reserve is … More than 1000× uranium exists in the oceans than exists in terrestrial ores. With nuclear power generation expected to increase over the coming decades, access to this unconventional reserve is a matter of energy security. With origins in the mid-1950s, materials have been developed for the selective recovery of seawater uranium for more than six decades, with a renewed interest in particular since 2010. This review comprehensively surveys materials developed from 2000-2016 for recovery of seawater uranium, in particular including recent developments in inorganic materials; polymer adsorbents and related research pertaining to amidoxime; and nanostructured materials such as metal-organic frameworks, porous-organic polymers, and mesoporous carbons. Challenges of performing reliable and reproducible uranium adsorption studies are also discussed, as well as the standardization of parameters necessary to ensure valid comparisons between different adsorbents.

Handbook on the Physics and Chemistry of Rare Earths

2015-01-01

Collectif Collectif

Uranium-series disequilibrium: Applications to Earth, Marine, and environmental sciences

1993-09-01

Neil C. Sturchio

Chemical thermodynamics of uranium

1993-03-01

M.G. Adamson

The Binary Rare Earth Oxides

1998-04-28

Gin‐ya Adachi , Nobuhito Imanaka

ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTThe Binary Rare Earth OxidesGin-ya Adachi and Nobuhito ImanakaView Author Information Department of Applied Chemistry, Faculty of Engineering, Osaka University, 2-1 Yamadaoka, Suita, Osaka 565-0871 Japan Cite … ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTThe Binary Rare Earth OxidesGin-ya Adachi and Nobuhito ImanakaView Author Information Department of Applied Chemistry, Faculty of Engineering, Osaka University, 2-1 Yamadaoka, Suita, Osaka 565-0871 Japan Cite this: Chem. Rev. 1998, 98, 4, 1479–1514Publication Date (Web):April 28, 1998Publication History Received8 September 1997Revised18 February 1998Published online28 April 1998Published inissue 1 June 1998https://pubs.acs.org/doi/10.1021/cr940055hhttps://doi.org/10.1021/cr940055hresearch-articleACS PublicationsCopyright © 1998 American Chemical SocietyRequest reuse permissionsArticle Views8414Altmetric-Citations817LEARN ABOUT THESE METRICSArticle Views are the COUNTER-compliant sum of full text article downloads since November 2008 (both PDF and HTML) across all institutions and individuals. These metrics are regularly updated to reflect usage leading up to the last few days.Citations are the number of other articles citing this article, calculated by Crossref and updated daily. Find more information about Crossref citation counts.The Altmetric Attention Score is a quantitative measure of the attention that a research article has received online. Clicking on the donut icon will load a page at altmetric.com with additional details about the score and the social media presence for the given article. Find more information on the Altmetric Attention Score and how the score is calculated. Share Add toView InAdd Full Text with ReferenceAdd Description ExportRISCitationCitation and abstractCitation and referencesMore Options Share onFacebookTwitterWechatLinked InRedditEmail Other access optionsGet e-Alertsclose SUBJECTS:Lanthanides,Metals,Oxides,Oxygen,Phase transitions Get e-Alerts

Self-consistent molecular-orbital methods. 22. Small split-valence basis sets for second-row elements

1982-05-01

Mark S. Gordon , J. Stephen Binkley , John A. Pople +2 more

ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTSelf-consistent molecular-orbital methods. 22. Small split-valence basis sets for second-row elementsMark S. Gordon, J. Stephen Binkley, John A. Pople, William J. Pietro, and Warren J. HehreCite this: … ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTSelf-consistent molecular-orbital methods. 22. Small split-valence basis sets for second-row elementsMark S. Gordon, J. Stephen Binkley, John A. Pople, William J. Pietro, and Warren J. HehreCite this: J. Am. Chem. Soc. 1982, 104, 10, 2797–2803Publication Date (Print):May 1, 1982Publication History Published online1 May 2002Published inissue 1 May 1982https://pubs.acs.org/doi/10.1021/ja00374a017https://doi.org/10.1021/ja00374a017research-articleACS PublicationsRequest reuse permissionsArticle Views1406Altmetric-Citations1554LEARN ABOUT THESE METRICSArticle Views are the COUNTER-compliant sum of full text article downloads since November 2008 (both PDF and HTML) across all institutions and individuals. These metrics are regularly updated to reflect usage leading up to the last few days.Citations are the number of other articles citing this article, calculated by Crossref and updated daily. Find more information about Crossref citation counts.The Altmetric Attention Score is a quantitative measure of the attention that a research article has received online. Clicking on the donut icon will load a page at altmetric.com with additional details about the score and the social media presence for the given article. Find more information on the Altmetric Attention Score and how the score is calculated. Share Add toView InAdd Full Text with ReferenceAdd Description ExportRISCitationCitation and abstractCitation and referencesMore Options Share onFacebookTwitterWechatLinked InRedditEmail Other access optionsGet e-Alertsclose Get e-Alerts

New Guidelines for δ13C Measurements

2006-02-16

Tyler B. Coplen , Willi A. Brand , Matthias Gehre +4 more

Consistency of delta13C measurements can be improved 39-47% by anchoring the delta13C scale with two isotopic reference materials differing substantially in 13C/12C. It is recommended that delta13C values of both … Consistency of delta13C measurements can be improved 39-47% by anchoring the delta13C scale with two isotopic reference materials differing substantially in 13C/12C. It is recommended that delta13C values of both organic and inorganic materials be measured and expressed relative to VPDB (Vienna Peedee belemnite) on a scale normalized by assigning consensus values of -46.6 per thousand to L-SVEC lithium carbonate and +1.95 per thousand to NBS 19 calcium carbonate. Uncertainties of other reference material values on this scale are improved by factors up to two or more, and the values of some have been notably shifted: the delta13C of NBS 22 oil is -30.03 per thousand.

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Recommendations for the definition, estimation and use of the detection limit

1987-01-01

Analytical Methods Committee

The detection limit is an important concept in trace analysis. However, analysts have been slow to adopt the IUPAC definition of detection limit, and as a consequence there is still … The detection limit is an important concept in trace analysis. However, analysts have been slow to adopt the IUPAC definition of detection limit, and as a consequence there is still a variety of usages in the current literature. The different usages can be reconciled by a proper specification of the analytical system in which the detection limit is measured. Because detection limit cannot be rigorously interpreted in terms of confidence intervals, there is little point in determining it with great precision. Nevertheless, when it is estimated by an appropriate means, it is an invaluable characteristic of an analytical system.

Transesterification

1993-06-01

Junzo Otera

ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTTransesterificationJunzo. OteraCite this: Chem. Rev. 1993, 93, 4, 1449–1470Publication Date (Print):June 1, 1993Publication History Published online1 May 2002Published inissue 1 June 1993https://pubs.acs.org/doi/10.1021/cr00020a004https://doi.org/10.1021/cr00020a004research-articleACS PublicationsRequest reuse permissionsArticle Views18473Altmetric-Citations809LEARN ABOUT … ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTTransesterificationJunzo. OteraCite this: Chem. Rev. 1993, 93, 4, 1449–1470Publication Date (Print):June 1, 1993Publication History Published online1 May 2002Published inissue 1 June 1993https://pubs.acs.org/doi/10.1021/cr00020a004https://doi.org/10.1021/cr00020a004research-articleACS PublicationsRequest reuse permissionsArticle Views18473Altmetric-Citations809LEARN ABOUT THESE METRICSArticle Views are the COUNTER-compliant sum of full text article downloads since November 2008 (both PDF and HTML) across all institutions and individuals. These metrics are regularly updated to reflect usage leading up to the last few days.Citations are the number of other articles citing this article, calculated by Crossref and updated daily. Find more information about Crossref citation counts.The Altmetric Attention Score is a quantitative measure of the attention that a research article has received online. Clicking on the donut icon will load a page at altmetric.com with additional details about the score and the social media presence for the given article. Find more information on the Altmetric Attention Score and how the score is calculated. Share Add toView InAdd Full Text with ReferenceAdd Description ExportRISCitationCitation and abstractCitation and referencesMore Options Share onFacebookTwitterWechatLinked InRedditEmail Other access optionsGet e-Alertsclose Get e-Alerts

Update on the chemical thermodynamics of uranium, neptunium, plutonium, americium and technetium

2003-01-01

R. Guillaumont , F. J. Mompeán

Uranium-series disequilibrium: applications to earth, marine, and environmental sciences. 2. ed

1992-01-01

Μ. Ivanovich , R. S. Harmon

The phenomenon of radioactivity geochemistry of actinides and their daughters uranium-series desequilibrium applications applications in geochronology chemical procedures spectroscopic methods mass spectrometry and applications to uranium-series disequilibrium igneous rocks uranium-series … The phenomenon of radioactivity geochemistry of actinides and their daughters uranium-series desequilibrium applications applications in geochronology chemical procedures spectroscopic methods mass spectrometry and applications to uranium-series disequilibrium igneous rocks uranium-series mobilization and surface hydrology ground water the oceanic chemistry of the uranium and thorium series nuclides radionuclides of the uranium and thorium decay series in the estuarine environment carbonate and sulphate precipitates marine sediments and sedimatentation processes uranium-series studies of marine phosphates and carbonates archaeological applications palaeclimatology and palaeoclimate records applications to radioactive waste disposal studies decay-series disequilibria applied to the study of rock-water interactions and geothermal systems applications od dating to denudation chronology and landscape evolution uranium-series disequilibrium in exploration geology applications of lead-210 to sedimentation studies.

Chemical thermodynamics of uranium

1992-01-01

Ingmar Grenthe , J. Fuger , Robert J. Lemire +3 more

Enhanced Photocatalytic Efficiency and Structural Stability of Uranyl-Organic Coordination Polymers via the Semirigid Ligand

2025-06-24

Zixin Wang , S. H. Tang , Kexin Xu +5 more | Inorganic Chemistry

Uranyl-organic coordination polymers (UOCPs) have been demonstrated to exhibit photocatalytic activity, but highly stable UOCPs with excellent photocatalytic efficiency are rare. Herein, we present a series of UOCPs built by … Uranyl-organic coordination polymers (UOCPs) have been demonstrated to exhibit photocatalytic activity, but highly stable UOCPs with excellent photocatalytic efficiency are rare. Herein, we present a series of UOCPs built by a semirigid benzimidazole-derived carboxyl ligand. By rationally designing the rigid and flexible sections of the ligand, we have obtained UO2(HBDA)(OH)·H2O (UOCP-SU-1), UO2(HBDA)(H2BDA)(NO3)·H2O (UOCP-SU-2), and UO2(HBDA)2 (UOCP-SU-3) with multiple spatial configurations under different conditions ([H3BDA]Cl = 1,3-bis(4-carboxybenzyl)-1,3-dihydro-2H-benzo[d]imidazol-2-iminium chloride). The structural and photoelectrochemical properties of these UOCPs were systematically investigated, and the relationship between coordination structure and the photocatalytic performance for photooxidation of benzylamine to N-benzylenzoimide has been well established. The UOCP-SU-1 with bridged oxygen ligands in the coordination structure exhibits the best visible-light response and chemical conformational stability activity. Importantly, the UOCP-SU-1 can maintain its original crystal structures after 10 cycles of catalysis. This work provides a novel strategy for developing efficient uranyl-based photocatalysts for organic reactions.

Pressure-Induced Enhanced Covalency Difference in the Coordination of Am(III)/Eu(III) with an Unsymmetric Phenanthroline Extractant

2025-06-24

Xiaocheng Xu , Shihui Wang , Xiaofan Yang +2 more | Inorganic Chemistry

The influence of high pressure on the coordination properties of f-block compounds is a topic of growing interest, which provides potential applications in the separation of actinide (An3+) and lanthanide … The influence of high pressure on the coordination properties of f-block compounds is a topic of growing interest, which provides potential applications in the separation of actinide (An3+) and lanthanide (Ln3+) ions. In this study, we explore the effect of high pressure on the bonding characteristics of the unsymmetric phenanthroline extractant (Et-Tol-CyMe4-ATPhen, L) in its complexes with Am3+ and Eu3+ using density functional theory (DFT) and various bonding analyses. Pressures ranging from 0 to 10 GPa are applied to investigate changes in the geometry, electronic structure, and bond covalency. Our results show that high pressure significantly enhances the covalent character of the bonds between L and Am3+/Eu3+, evidenced by increased electron density ρ(r), delocalization indices (DI), stronger covalent orbital interactions (ΔEorb), and interatomic exchange interactions (Vxc). Notably, while the Eu-L bond lengths contract more than the Am-L bonds, the 5f orbitals of Am3+ are more sensitive to pressure than the relatively contracted 4f orbitals of Eu3+, resulting in an enhanced covalency difference confirmed by natural localized molecular orbital (NLMO) analysis. These findings highlight the significant role of high pressure in altering the bonding characteristics of f-block compounds, opening new avenues for further studies of highly efficient Am3+/Eu3+ separation.

The effect of alkyl substituent on selective extraction trivalent Am from Eu ions by pyridylpyrazole ligands: A DFT study

2025-06-24

Cui Wang , Wenbo Lan , Dingding Wang +4 more | Journal of the Taiwan Institute of Chemical Engineers

Nucleotide-grafted coal for high-efficiency removal of uranium: performance, optimisation, and insight into the adsorption mechanism

2025-06-23

Mohd Azfar Shaida , A. K. Sen , Raj Kumar Dutta | Environmental Science and Pollution Research

Boron Oxides, Boric Acid, and Borates

2025-06-23

David M. Schubert | Kirk-Othmer Encyclopedia of Chemical Technology

Abstract Boron oxides comprise a diverse family of compounds in which boron is exclusively bonded to oxygen. Known as borates, these include nearly all naturally occurring boron compounds and industrial … Abstract Boron oxides comprise a diverse family of compounds in which boron is exclusively bonded to oxygen. Known as borates, these include nearly all naturally occurring boron compounds and industrial chemicals and minerals used in the manufacture of products important to society. Boron oxides are found everywhere in rocks, soil, and natural waters. However, large borate mineral deposits are rare. Only a few of the more than 200 known borate minerals are primary sources of industrial borates. These minerals are extracted in Turkey, the United States, South America, and Asia. Major borate products include boric acid, borax pentahydrate, borax decahydrate, anhydrous borax, boric oxide, and zinc borate. Beneficiated colemanite and ulexite ores are also utilized on industrial scale. Specialized products include ammonium, lithium, potassium, and barium borates, which may take the form of metaborates, tetraborates, and pentaborates, among others. Physical properties and nomenclature systems of borates are reviewed. The largest application of borates is in the manufacture of glass, including energy‐saving insulation fiberglass and borosilicate glasses. One major application is flat panel displays for TVs, computers, and mobile devices. Other uses include in ceramics, building materials, metallurgy, housewares, agriculture, fire retardants, and lubricants. Boron is required by all vascular plants. Boron micronutrient fertilizers are routinely applied where soils are deficient in order to improve crop yields and quality. High levels of boron inhibit bacteria, decay fungi, and insects, providing the basis for their use in the protection of wood‐based building products. Environmental, health, and safety aspects of borates are reviewed.

Thermal Transformations of Radicals Derived from Nuclear Waste Separation Ligands Exposed to Radiation

2025-06-23

Ilya S. Sosulin , Aliaksandra Lisouskaya | The Journal of Physical Chemistry A

The thermal evolution of electron-beam-induced radicals generated in neat di-n-butyl N,N-diethylcarbamoylphosphonate (DBDECP), N,N-bis(2-ethylhexyl)butanamide (DEHBA), dioctyl phosphate (DOP), tributyl phosphate (TBP), and N,N,N',N'-tetraoctyl diglycolamide (TODGA), and TBP/dodecane extraction system was investigated … The thermal evolution of electron-beam-induced radicals generated in neat di-n-butyl N,N-diethylcarbamoylphosphonate (DBDECP), N,N-bis(2-ethylhexyl)butanamide (DEHBA), dioctyl phosphate (DOP), tributyl phosphate (TBP), and N,N,N',N'-tetraoctyl diglycolamide (TODGA), and TBP/dodecane extraction system was investigated using electron paramagnetic resonance (EPR) spectroscopy over the temperature range of 108-220 K. Density functional theory (DFT) calculations were employed to support the experimental results, clarifying radical structures and energetics of their thermal transformations. The stability of radicals as temperature increased varied significantly depending on the ligand structure. The diglycol- or amide-centered radicals, such as those found in TODGA and DEHBA, exhibited higher thermal stability than the alkyl radicals. This increased stability is attributed to the greater steric hindrance in the latter species. Calculated energy barriers (∼20 kcal/mol) suggested that thermal evolution predominantly involves conformational rearrangements of the radicals, rather than transformations of the radical structure itself. Additionally, trace amounts of oxygen led to the conversion of carbon-centered radicals into peroxide radicals during thermal annealing. The peroxide radicals formed decomposed more rapidly at elevated temperatures. This study provides important mechanistic insights into the radiolytic degradation of nuclear waste extraction ligands, helping to advance the development of more radiation-resistant solvents for nuclear waste separation processes.

Cation–Cation Interactions in Neptunium(V,VI)-diglycolamide System

2025-06-20

Christelle Tamain , Matthieu Autillo , Dominique Guillaumont +2 more | Inorganic Chemistry

The SC-XRD structure and Raman spectra of two new mixed-valence Np(V)-Np(VI) compounds with cation-cation interactions (CCIs) using TEDGA (tetraethyldiglycolamide, belonging to the diglycolamide family) as a ligand are reported: a … The SC-XRD structure and Raman spectra of two new mixed-valence Np(V)-Np(VI) compounds with cation-cation interactions (CCIs) using TEDGA (tetraethyldiglycolamide, belonging to the diglycolamide family) as a ligand are reported: a trimeric species, [NpVO2(TEDGA)2]2[NpVIO2(NO3)2](NO3)2 (1), which is the first neptunium representative of a linear actinide trimer with CCIs, and a dimeric species, [NpVO2(TEDGA)2][NpVIO2(NO3)3]·CH3CN (2). These two structures were prepared thanks to controlled and reproducible syntheses, based on the mixing of the two monomer solutions in an inert solvent: a Np(V)-TEDGA monomer solution mixed with a dinitrate or trinitrate Np(VI) solution. To better understand the impact of the CCIs on the actinyl cation electronic properties, these structures were compared to the constituent monomers, [NpVO2(TEDGA)2]+ (3), which was also synthesized, and NpVIO2(NO3)2(H2O)2. To complete the series, the [NpVIO2(TEDGA)2]2+ (4) monomer is also reported. In addition, DFT calculations were performed to aid in interpreting the Raman experimental data, to characterize the bonding in such polynuclear species, and to identify the main parameters influencing the stability of cation-cation structures, such as the nature of counterions, the influence of alkyl chains and the presence of weak intra- or intermolecular interactions.

Synthesis, investigation of the structure and physico-chemical properties of modified solid-phase extractants (SPE) based on N,N,N’,N’-tetraoctyldiglycolamide (TODGA)

2025-06-19

A. A. Savelev , V. I. Rachkov | Nuclear Energy and Technology

The paper presents the results of the development of modified solid-phase extractants (SPE) based on N,N,N’,N’-tetraoctyl diglycolamide (TODGA) intended for the selective extraction of americium-241 from nitric acid solutions of … The paper presents the results of the development of modified solid-phase extractants (SPE) based on N,N,N’,N’-tetraoctyl diglycolamide (TODGA) intended for the selective extraction of americium-241 from nitric acid solutions of liquid radioactive waste. (LRW). The structural and physico-chemical properties of synthesized materials, including granulometric composition, porosity, and stability in nitric acid media, have been studied. The developed SPEs are stable in nitric acid solutions and meet the size requirements for use in industrial sorption columns. The results obtained can be used as a basis for creating technological schemes for the processing of LRW based on synthesized experimental modified samples of SPETODGA, in particular for the isolation of minor actinides, including americium-241.

Interface-driven electronic modulation enhances U S coordination in carbon-confined Co-Mo sulfide heterojunctions for electrochemical uranium extraction

2025-06-18

Qianxi Li , Jianguo Zhou , Yingsheng Xu +2 more | Chemical Engineering Journal

Controls on uranium isotope fractionation in the late Paleoproterozoic ocean

2025-06-18

Alexandra Kunert , Simon W. Poulton , Donald E. Canfield +3 more | Earth and Planetary Science Letters

Simulation of multiple parameter effects on efficiency of uranium ore acid leaching

2025-06-18

Guijun Luo , Chuanfei Zhang , Xiangxue Zhang +3 more | Annals of the New York Academy of Sciences

Abstract This study investigates factors influencing the leaching process in uranium mining, using a uranium mine in Inner Mongolia, China, as a representative case. We used PHREEQC geochemical and COMSOL … Abstract This study investigates factors influencing the leaching process in uranium mining, using a uranium mine in Inner Mongolia, China, as a representative case. We used PHREEQC geochemical and COMSOL Multiphysics® software, as well as the coupling interface COMSOL PHREEQC (iCP), to simulate acid leaching of underground core mineral samples. The study systematically analyzes the effects of sulfuric acid concentration, permeability coefficient, and injection/leaching pressure differential on uranium leaching efficiency. It also reveals spatial and temporal variations of minerals throughout the leaching process. The findings include a positive correlation between sulfuric acid concentration and leaching rate. Increased permeability significantly enhanced the leaching effect, while the injection/leaching pressure differential had an optimal range. Additionally, mineral evolution characteristics suggested that acidophilic minerals dissolve rapidly in initial stages, whereas later stages may involve minerals such as kaolinite and quartz influencing pore structure. These findings provide a foundation for optimizing process parameters in uranium mining and offer a quantitative reference for micro‐scale mineral changes, ultimately for efficient and sustainable uranium extraction.

Temporal and spatial evolution of chemical composition in acid in-situ leaching of uranium

2025-06-18

Xuefeng Liu , Jinhui Liu , Ting He +3 more | Journal of Radioanalytical and Nuclear Chemistry

A novel slow-release citric acid for enhancing the phytoremediation of uranium-contaminated soil by Indian mustard (Brassica juncea L.) and ryegrass (Lolium perenne L.)

2025-06-18

Kai Yang , Xue Yu , Runchuan Fan +4 more | Journal of Cleaner Production

A critical review on photocatalytic reductive conversion of uranium by CdS-based catalysts

2025-06-17

Zhiren Guo , Xiyan Xu , Jinlei Song +7 more | Journal of environmental chemical engineering

Research on pretreatment methods for measurement of Sr-90 in cement solidified body leachates

2025-06-17

Shuang Dai , Xuecong Li , Mengxing Li +4 more | Journal of Radioanalytical and Nuclear Chemistry

Separation of uranium with nanofibers treated with phosphorus-containing chelating agents: kinetics, thermodynamics, isotherms and reusability

2025-06-17

Guoquan Sun , Di Zhang , Wei Dai +4 more | Journal of Radioanalytical and Nuclear Chemistry

Bio–Nano Interactions of Recombinant Cyanobacterial Metallothionein with Magnetic Nanoparticles for the Removal of Cadmium and Uranium

2025-06-17

T. V. Divya , Bijaideep Dutta , Kaustava Bhattacharyya +2 more | ACS Omega

Gamma radiation in highly compacted FEBEX bentonite: key microbial and mineralogical behavior for safety assessment of nuclear repositories

2025-06-16

Mar Morales‐Hidalgo , Cristina Povedano‐Priego , Marcos F. Martinez-Moreno +7 more | Journal of Hazardous Materials

One of the major challenges for future Deep Geological Repositories (DGRs) for radioactive waste is to ensure long-term safety over timescales exceeding 100,000 years. The effect of gamma radiation on … One of the major challenges for future Deep Geological Repositories (DGRs) for radioactive waste is to ensure long-term safety over timescales exceeding 100,000 years. The effect of gamma radiation on bentonite microorganisms remains poorly understood, with even less research exploring its combined impact with other key repository conditions. This study investigates the combined effects of high bentonite compaction density (1.6 g/cm3) and gamma radiation (cumulative doses 14 kGy or 28 kGy) on FEBEX bentonite blocks under complete water saturation with synthetic pore water, anoxic atmosphere, and sulfate-reducing bacteria (SRB). Culture-dependent microbiological analyses and next-generation sequencing demonstrated that native FEBEX bentonite microorganisms can withstand these challenging conditions, favoring spore-forming bacteria. After 1-year incubation, in both non-irradiated and irradiated samples, extremophile genera like Saccharopolyspora and Streptomyces, were identified. In addition, gamma radiation negatively impacted heterotrophic aerobe viability. However, a key finding was that a 6-month incubation period prior to radiation exposure enhanced microbial resistance to this stressor. Mineralogically, neither gamma radiation nor other studied conditions affected the properties of FEBEX bentonite, which remained stable. This study provides groundbreaking insights into the combined effects of gamma radiation and other DGR-relevant conditions on bentonite microbiology and mineralogy, significantly advancing the field.

U4+ Speciation in Acidic Aqueous Solution: Insights from UV–Vis, EXAFS, XANES, and Quantum-Statistical Simulations

2025-06-16

Gema Raposo-Hernández , Rafael R. Pappalardo , Florent Réal +2 more | Inorganic Chemistry

This theoretical study investigates the UV-vis absorption properties of U4+-containing aqueous solutions and their relationship with the nature of aqua-complexes present at varying acidic levels. High-level quantum-mechanical calculations─accounting for relativistic … This theoretical study investigates the UV-vis absorption properties of U4+-containing aqueous solutions and their relationship with the nature of aqua-complexes present at varying acidic levels. High-level quantum-mechanical calculations─accounting for relativistic effects, spin-orbit coupling, and both dynamic and nondynamic correlation─were combined with classical Molecular Dynamics simulations. EXAFS, XANES, and UV-vis spectra of U4+-containing aqueous solutions were used as experimental reference data and compared with the corresponding theoretical predictions. UV-vis spectra were available at various pH values. Theoretical spectra were generated as averages of individual spectra computed from the structures statistically generated. Coordination numbers ranging from 8 to 10 for the aqua ion were explored. Although the theoretical-experimental comparison of the EXAFS and XANES spectra allows us to reject ten-coordination, assigning the octa- or nine- (ennea-)coordination to the U4+ aqua ion is difficult. However, UV-vis spectroscopy provided some evidence supporting a preference for the ennea-coordination. Spectra for aqueous solutions up to pH 2.22 were compared with simulated spectra of hydrolyzed forms of the aqua ion, in which up to two water molecules were replaced by hydroxyl anions. Spectra obtained as simulated mixtures of the aqua ion and hydrolyzed species in varying ratios produced a spectral evolution with pH that closely resembles experimental observations.

Separation of dilute plutonium(IV) from nitric acid solutions via Reillex HPQ anion exchange resin

2025-06-16

Matthew S. Mills , Sara Mills , R. Carter +2 more | Separation Science and Technology

FAUST. XXV. A potential new molecular outflow in [BHB2007]11

2025-06-16

Antonio Martínez-Henares , I. Jiménez-Serra , C. Vastel +7 more | Astronomy and Astrophysics

During the early stages of star formation, accretion processes such as infall from the envelope and molecular streamers and ejection of matter through winds and jets take place simultaneously and … During the early stages of star formation, accretion processes such as infall from the envelope and molecular streamers and ejection of matter through winds and jets take place simultaneously and distribute the angular momentum of the parent molecular cloud. The Class 0/I binary BHB2007 11 shows evidence for accretion and ejection at the scales of the circumbinary disk and the inner close binary. Recent observations of H_2CO, however, have shown two elongated structures with indications of outflowing motion almost perpendicular to the main CO outflow, which is launched from the circumbinary disk. We study the kinematics of the molecular gas at intermediate scales of ∼50-3000,au around BHB2007 11 to verify the nature of these elongated structures. We analyzed the line emission of H^13CO^+, CCH, c-C_3H_2, and SiO observed with the Atacama Large Millimeter/submillimeter Array (ALMA) within the large program called Fifty AU STudy of the chemistry in the disc/envelope system of Solar-like protostars (FAUST). These molecules trace the material that moves at velocities close to that of the ambient cloud, which could not be probed in previous observations of the self-absorbed emission of CO. The images of H^13CO^+, CCH, and c-C_3H_2 show clear elongated structures similar to those previously detected in H_2CO, whose gas kinematics are consistent with outflowing motions and with rotation in the opposite sense to the main CO outflow. The derived mass-loss rate from these large-scale structures is $(1.8±0.5) M_ ⊙ yr $, which agrees with the rates measured in outflows driven by Class 0/I protostars. The SiO image reveals compact emission close to the binary system, with a slight elongation that is aligned with the larger-scale structures. This suggests that SiO is released from the sputtering of dust grains in the shocked material at the base of the potential new outflow, with a relative abundance of ≥(0.11-2.0) However, higher angular and spectral resolution observations are needed to accurately estimate the outflow-launching radius and its powering source. Based on the location and the abundance of the SiO emission, we propose that the second outflow may be launched from inside the circumbinary disk, likely by the less massive companion that actively accretes material from its surroundings.

Uranium (VI) electrochemical remediation in water at nano zero-valent iron particles (nZVIs) modified boron-doped diamond electrodes

2025-06-16

Alexis J. Acevedo-González , Daniel Torres , Jaileen R. Caicedo-Villamil +2 more | Journal of Applied Electrochemistry

Streamlining and Simplifying the Chemical Separation of Berkelium (249Bk) from Other Actinides/Lanthanides and Fission Products

2025-06-16

Miting Du , P. Thakur | ACS Omega

Gamma radiolytically synthesized phosphate decorated gold nanoparticles for ultra-trace level detection of U(VI) in water

2025-06-16

Nilanjal Misra , Swarnima Rawat , Shubhangi A. Shelkar +3 more | Discover Nano

We describe the 60Co-Gamma radiolytic synthesis of stable poly(bis[2-(methacryloyloxy)ethyl] phosphate) (PB2MEP) -decorated gold nanoparticles (PB2MEP-Au) for spectrophotometric detection of uranium (U(VI)) in the ppb level. The developed technique is based … We describe the 60Co-Gamma radiolytic synthesis of stable poly(bis[2-(methacryloyloxy)ethyl] phosphate) (PB2MEP) -decorated gold nanoparticles (PB2MEP-Au) for spectrophotometric detection of uranium (U(VI)) in the ppb level. The developed technique is based on the Localize Surface Plasmon Resonance (LSPR) band intensity quenching, accompanied by a red shift in the wavelength range 523-545 nm at higher concentrations, due to interaction between U(VI) ion and phosphate group bearing PB2MEP-Au. The response was linear in the 5-80 ppb U(VI) concentration range, with LOD of 8.6 ppb. Samples were characterized by transmission electron microscopy, Particle Size Analysis and Zeta Potential measurements to determine morphological transitions upon analyte interaction. Density Functional Theory (DFT) calculations were invoked to study the Au nanoparticle stabilization mechanism, and revealed the interaction of U(VI) with PB2MEP-Au to be thermodynamically spontaneous for the formation of [UO2(B2MEP)2(H2O)]2+ complex, the stability primarily driven by entropy. Interference by other coexisting metal ions was negligible up to interferent:target ratios of 10:1. The method was validated through quantification of U(VI) in water samples spiked with known U(VI) concentrations, the results being in corroboration with those reported using laser fluorimetric method. A T-test confirmed the results derived from the proposed method were not significantly different from those obtained using the standard estimation protocol at a 95% confidence level.

A Tetradentate Chelator for Reducing Damage Caused by Uranium

2025-06-16

Yong Li , Bin Yang , Wangbo Qu +7 more | Inorganic Chemistry

The rapid advancement of the nuclear industry has precipitated significant challenges in nuclear pollution, with radionuclide uranium emerging as a formidable threat to human safety due to its potent chemical … The rapid advancement of the nuclear industry has precipitated significant challenges in nuclear pollution, with radionuclide uranium emerging as a formidable threat to human safety due to its potent chemical toxicity and radioactivity. The development of uranium chelators represents a pivotal strategy in mitigating the internal damage caused by nuclear exposure. While the US Food and Drug Administration has approved certain drugs for this purpose, issues such as low selectivity and high toxicity remain unresolved. In this study, a tetradentate chelating agent, MDDO was synthesized. Compared with the commercially available agent CaNa3-DTPA, MDDO exhibits markedly lower toxicity. In addition, the addition of MDDO markedly reduced the extent of cellular damage caused by uranium. In vivo studies have shown that immediate administration of MDDO achieves removal rates of uranyl ions at 49.6% in the kidneys and 52.0% in the femurs. These findings not only underscore the potential of MDDO as a uranium chelator but also pave the way for the development of radionuclide decorporation agents, offering fresh perspectives in the ongoing quest to enhance nuclear safety and public health.

The Effect of Diluents and Phase Modifiers on Lanthanide(III) and Actinide(III) Extraction by Diglycolamide Extractants

2025-06-16

Wyatt S. Nobley , Mark P. Jensen | Solvent Extraction and Ion Exchange

Separate Determination of Strontium and Barium Mass Fractions in Calcite and Dolomite in Carbonate Rocks by a Multi‐step Sequential Leaching Procedure

2025-06-14

Kuang Jen Wu , Yuichiro Ueno , Jakub Surma +1 more | Geostandards and Geoanalytical Research

Trace element partitioning in carbonate minerals has shown potential in palaeoenvironment reconstruction, while one of its preconditions of application – the respective extraction of trace element mass fractions in diverse … Trace element partitioning in carbonate minerals has shown potential in palaeoenvironment reconstruction, while one of its preconditions of application – the respective extraction of trace element mass fractions in diverse mineral phases in carbonate rocks – leaves room for methodological improvement. We tested a ten‐step sequential leaching method to selectively dissolve and extract calcite and dolomite based on their different reactivities to dilute acetic acid, with a focus on strontium and barium release. A group of mineral samples and a group of rock samples were selected for the experiment. The constant release of Sr from both calcite and dolomite mineral samples indicates its uniform distribution in the two carbonate minerals, which is consistent with prior conclusions that Sr is incorporated in the carbonate lattice, substituting for Ca. For carbonate rocks, the Sr and Ba contents present linear correlations with the ratio of calcite and dolomite, as well as Ca/(Mg+Ca) ratio dissolved in each leaching step, suggesting that the determination of their mass fractions in the two minerals can be achieved by regression. Although the Ba abundance in mineral samples is similar to that of Sr, its pattern of release from rock sample powder shows significant non‐carbonate contributions. Based on the results of the sequential leaching, we design a multi‐step procedure for the separate extraction of Sr and Ba in calcite and dolomite, and a case study is conducted to demonstrate its applicability, the results of which show a significantly lower Ba content in the carbonate minerals compared with bulk Ba concentrations, emphasising the importance of being cautious when using element abundances in carbonate rocks to reconstruct geochemical properties of the palaeoenvironment.

Radiation-induced degradation of sulfonamides (SAs) antibiotics by gamma radiation: Effect of ferrous ion

2025-06-13

Yuankun Liu , Yongwei Song , Jianlong Wang | Radiation Physics and Chemistry

Assessing the timing of deep ocean oxygenation from uranium elemental and isotopic compositions of ophiolites

2025-06-13

Joel Rodney , Morten B. Andersen , Daniel Stubbs +4 more | Earth and Planetary Science Letters

Assessing nonpoint-source uranium pollution in an irrigated stream-aquifer system

2025-06-13

Ibraheem A Qurban , Timothy K. Gates , Eric D. Morway +4 more | The Science of The Total Environment

Sensitivity of mass-independent Sn isotope fractionation to UV radiation and magnetic fields

2025-06-12

Jia-Xin She , Weiqiang Li , Shujuan Zhang +5 more | Proceedings of the National Academy of Sciences

Mass-independent isotope fractionation (MIF) enables powerful geochemical tracers for various geological and planetary problems, yet the mechanisms driving MIF for tin (Sn) remain ambiguous. Here, we demonstrate that distinct Sn … Mass-independent isotope fractionation (MIF) enables powerful geochemical tracers for various geological and planetary problems, yet the mechanisms driving MIF for tin (Sn) remain ambiguous. Here, we demonstrate that distinct Sn isotope fractionation signatures were produced during photolysis of organic Sn species (i.e., methyltin) under laboratory UV irradiation and natural sunlight. UV irradiation of methyltin induced pronounced Sn-MIF in all odd Sn isotopes (Δ 115 Sn up to 21.82‰, Δ 117 Sn up to 23.16‰, Δ 119 Sn up to 24.01‰), with their ratios (Δ 117 Sn/Δ 115 Sn = 1.069; Δ 119 Sn/Δ 115 Sn = 1.099; Δ 119 Sn/Δ 117 Sn = 1.028) strongly correlating with nuclear magnetic moments. This unambiguously identifies the magnetic isotope effect (MIE) as the driving mechanism, ruling out other causes such as the nuclear volume effect (NVE). Methyl radicals (•CH 3 ) were detectable during the methyltin photolysis experiments, and the magnitude of MIF for Sn was suppressed by the presence of electron spin trapping agent (DMPO) for radicals, supporting that the pronounced Sn-MIF originated from radical-mediated singlet-triplet state transitions of Sn species. Furthermore, the magnitude of Sn-MIF depended nonmonotonically on external magnetic fields (peak suppression at 100 to 180 G), implying competition between hyperfine coupling and Zeeman interactions. Notably, Sn-MIF was absent during photolysis of methyltin by natural sunlight despite significant mass-dependent Sn isotope fractionation (e.g., >3‰ in δ 122/116 Sn), attributed to atmospheric ozone shielding of short-wavelength UV (<290 nm) required for radical generation. Our results register Sn-MIF as a sensitive tracer of UV-driven photochemistry in low-oxygen environments, underlining the potential of Sn isotopes in studies of early Earth’s atmosphere and planetary environments.

Solvation Effects on the Sustainability of Lanthanum Complexes

2025-06-12

Maxim A. Lutoshkin | The Journal of Physical Chemistry A

In this article, we performed a detailed computational study of the interaction La3+ ion with eight perfluorinated β-diketones bearing heterocyclic rings and trifluoromethyl groups. The chelation process between trivalent lanthanum … In this article, we performed a detailed computational study of the interaction La3+ ion with eight perfluorinated β-diketones bearing heterocyclic rings and trifluoromethyl groups. The chelation process between trivalent lanthanum and furoyl-trifluoroacetone, thenoyl-trifluoroacetone, selenoyl-trifluoroacetone, tellurophen-trifluoroacetone, benzoyl-trifluoroacetone, pyridine-trifluoroacetone, N-methyl-pyrrol-trifluoroacetone, and N-methyl-pyrazole-trifluoroacetone has been simulated by means of DFT using three scalar relativistic effective core potentials (CRENBL ECP, Def2-ECP, and LANZL2DZ ECP) and three solvation models (C-PCM, SMD, and COSMO). Coordination models with different numbers of water molecules in the solvation shells have been tested for the calculation of stability constants and to estimate the influence of the coordination environment on the thermodynamic stability of complexes. Formation constants were evaluated using a thermodynamic cycle involving complex species with two, four, five, six, seven, eight, and ten coordination numbers. The performed calculations demonstrate that the number of water molecules in the solvation shell is a key factor for the sustainability of dicarbonyl chelates. Theoretical values of stability constants lie in the range of -10 to 23 logarithmic units and are in agreement with the experiment for low-coordinated models. TD-DFT simulation also indicates six-coordination as the most acceptable at the cc-pVDZ/CAM-B3LYP level of theory.

Radiochemistry education and demand

2025-06-12

Shams Al Azzawi , Julio Marín , Braden Goddard | Nuclear Science and Technology Open Research

<ns5:p>Background Radiochemistry, an interdisciplinary field integrating nuclear engineering, chemistry, and physics, plays a critical role in energy, security, and medical applications. Despite its importance, radiochemistry remains underappreciated, with limited educational … <ns5:p>Background Radiochemistry, an interdisciplinary field integrating nuclear engineering, chemistry, and physics, plays a critical role in energy, security, and medical applications. Despite its importance, radiochemistry remains underappreciated, with limited educational opportunities at the undergraduate level and a workforce that struggles to meet growing demands. This paper examines the current state of radiochemistry education and workforce needs in the United States. Method This study reviews available undergraduate and graduate programs in radiochemistry, including degrees, specializations, and research opportunities at institutions such as the University of Nevada Las Vegas and Pennsylvania State University. It also analyzes certifications offered by organizations like the Radiochemistry Society and the American Board of Health Physics. Workforce data, including employment statistics and projected demand, are drawn from published reports and recent literature. Results Findings reveal a scarcity of undergraduate programs, with only a few universities offering concentrations in radiochemistry. Graduate programs are more prevalent, particularly at the Ph.D. level. Workforce data from 2012 indicate a significant gap between supply and demand, with an estimated need for 200 bachelor-level, 93 master-level, and 306 Ph.D.-level radiochemists. Recent advancements in nuclear medicine and energy suggest this demand has likely increased. Conclusion Despite challenges, the field shows promising growth, supported by increased funding and educational initiatives. Strengthening radiochemistry education and training programs is essential to meet workforce demands and leverage the field’s potential in energy, security, and healthcare. Continued support from government agencies and organizations will be critical to sustaining this progress.</ns5:p>

Water-Soluble Masking Agent with a Phenanthroline Skeleton for the Highly Selective Separation of Am(III) and Ln(III) by TODGA

2025-06-12

Wei-Jia Wang , Feng Zhang , Jinlei Liu +7 more | Inorganic Chemistry

The i-SANEX process has been developed as a promising strategy for the separation of trivalent lanthanide-actinides, which can effectively overcome the poor solubility of N-donors in nonpolar solvents. In this … The i-SANEX process has been developed as a promising strategy for the separation of trivalent lanthanide-actinides, which can effectively overcome the poor solubility of N-donors in nonpolar solvents. In this study, four hydrophilic phenanthroline-based ligands (L1-L4) with different terminal groups were synthesized to evaluate their water solubility and masking effects on An(III) in aqueous solutions using competitive extraction dominated by TODGA. Among these ligands, BHEO-DAPhen (L1), featuring an ethoxyethanol-modified side chain, demonstrated the best overall performance in both solubility and selectivity. Competitive two-phase extraction experiments confirmed that L1 significantly enhanced the separation factor (SFEu/Am), reaching a striking maximum value of 558 in 0.6 M HNO3. The coordination behavior of L1 with trivalent metal ions was comprehensively investigated using UV-visible titration, 1H NMR titration, IR spectroscopy, ESI-HRMS, TRLFS spectroscopy, and X-ray single-crystal diffraction. DFT calculations also revealed that the exceptional selectivity of L1 toward Am(III) is attributed to stronger covalent interactions than Eu(III). These results demonstrated the potential of L1 as a promising masking agent for the selective separation of An(III) and Ln(III), providing valuable insights for the treatment of next-generation nuclear wastes.

Excited States and Luminescent Properties of Uranyl Carbonates and Their Hydrated Complexes in Aqueous Solution: A Theoretical Study

2025-06-12

Zhen Zhao , Jiajia Yang , Jing Su | Inorganic Chemistry

Understanding the luminescence properties of uranyl complexes is essential for predicting their coordination chemical behavior. This study systematically investigates the low-energy excited states of [(H2O)xUO2(CO3)n]2-2n (x = 0-3, n = … Understanding the luminescence properties of uranyl complexes is essential for predicting their coordination chemical behavior. This study systematically investigates the low-energy excited states of [(H2O)xUO2(CO3)n]2-2n (x = 0-3, n = 1-3) using CCSD(T) and CASPT2 methods. The results show that the ligand field exerts comparable effects on both the ground and lowest excited states (3Δg) at the scalar relativistic level, whereas the spin-orbit coupling effects on the luminescence spectral profile are minimal in (near-)saturated coordination environments. Based on these findings, key correlations are established: (1) between the equilibrium bond length of uranium and axial oxygen (U-Oax) in the ground state (Re,g) and U-Oax bond length elongation upon excitation (ΔRe), and (2) between Re,g and the excitation energy difference (ΔΔE) of vertical and adiabatic one. These relationships are further validated in previously reported uranyl-dichloride-water and uranyl-difluoride-water systems. Leveraging these correlations, a predictive approach is developed to estimate the luminescence spectral parameters of structurally intricate complexes using the calculation results of simple uranyl compounds in the same primary-ligand coordination environment and only the Re,g and the lowest vertical excitation energy of the intricate complexes, thus avoiding extensive computational cost. This predictive framework provides a robust tool for predicting the spectral properties of complex uranyl systems.

Advanced Analysis of X-ray Fluorescence Measurements of the Interfacial Density of Eu Ions at Liquid–Liquid Interfaces for Solvent Back-Extraction

2025-06-12

Zhu Liang , Wei Bu , Mohammed A. Karim +6 more | The Journal of Physical Chemistry A

X-ray fluorescence near total reflection (XFNTR) is the primary technique used to measure the element-specific interfacial density of ions at liquid-liquid interfaces. Fluorescence from ions in the bulk liquids can … X-ray fluorescence near total reflection (XFNTR) is the primary technique used to measure the element-specific interfacial density of ions at liquid-liquid interfaces. Fluorescence from ions in the bulk liquids can complicate the determination of the interfacial density; consequently, measurements have been previously limited to samples without ions in the upper phase and with concentrations on the order of 10 μM or less in the lower phase. We modify the analysis of XFNTR data to account for ions in both bulk phases, then demonstrate its use in the context of rare-earth separations processes. In a model of ion stripping (i.e., back-extraction), dodecane solutions of di(2-ethylhexyl)phosphoric acid (HDEHP) loaded with Eu(III) at the 1 mM level are placed in contact with either pure water or aqueous solutions of nitric or citric acid at pH 3. XFNTR measurements of equilibrated, quiescent samples reveal that citric acid solutions produce a disproportionately large depletion of ions from the interface compared to that from the bulk organic solution, whereas stripping by pure water or nitric acid solutions is negligible. This advance in the methodology of XFNTR may have broad applicability to the investigation of metal ions in chemical and biological processes at liquid-liquid interfaces.

Electrochemical Investigation of Uranyl Nitrate in Ethaline DES and a New Approach for Direct Electrochemical Deposition of UO2

2025-06-12

Jalaj Varshney , Ashutosh Srivastava , M. Ameen Sha +1 more | Journal of The Electrochemical Society

Abstract In the present study, systematic investigation of uranyl nitrate (UO2(NO3)2) dissolution in choline chloride-ethylene glycol (1.2 ratio; ethaline) deep eutectic solvent (DES) was done. Post dissolution, the electrochemical behavior … Abstract In the present study, systematic investigation of uranyl nitrate (UO2(NO3)2) dissolution in choline chloride-ethylene glycol (1.2 ratio; ethaline) deep eutectic solvent (DES) was done. Post dissolution, the electrochemical behavior of uranyl species was monitored using cyclic voltammetry (CV), chronoamperometry (CA) and differential pulse voltammetric techniques on both Pt as well as on glassy carbon (GC) electrodes at different temperatures. Detailed CV and CA analyses confirmed diffusion controlled reduction of uranyl ion which was quasi-reversible in nature on Pt electrode but irreversible in nature on GC electrode. Based on the electrochemical investigations, the electron transfer mechanism, diffusion coefficient and kinetic rate constants were determined. For the first time, direct electrodeposition of UO2 from novel DES-based electrolyte UO2(NO3)2-ethaline was attempted and successfully deposited on copper electrode as confirmed by GIXRD of the deposited film. Deposited films surface morphology and chemical composition were further analyzed using field-emission scanning electron microscopy combined with energy-dispersive spectroscopy and X-ray photoelectron spectroscopy analysis respectively. The strategy adopted for the deposition of uranium oxide from DES can be implemented as novel recovery and obtaining thin films of uranium oxide.

Alkali Counterion-Dependent Crystallization of Uranium(IV)–Chloro Structural Units

2025-06-12

Madeline C. Shore , Jennifer N. Wacker , Pere Miró +2 more | Inorganic Chemistry

The synthesis, structural characterization, and spectroscopic properties of five tetravalent uranium (U) phases including Li6[U4(μ3-O)2Cl18(H2O)2]·10H2O (1), [U(H2O)4Cl4] (2), [U(H2O)4Cl4]·KCl (3), Rb2UCl6 (4), and Cs2UCl6 (5) are reported. Notably, a change … The synthesis, structural characterization, and spectroscopic properties of five tetravalent uranium (U) phases including Li6[U4(μ3-O)2Cl18(H2O)2]·10H2O (1), [U(H2O)4Cl4] (2), [U(H2O)4Cl4]·KCl (3), Rb2UCl6 (4), and Cs2UCl6 (5) are reported. Notably, a change in the U4+ solid-state structural unit was observed based on the identity of the alkali counterion used in the synthesis. Li1+ yielded a tetranuclear oxo-bridged cluster, [U4(μ3-O)2Cl18(H2O)2]6-, Na1+ and K1+ yielded two structurally distinct [U(H2O)4Cl4] complexes, and Rb1+ and Cs1+ resulted in [UCl6]2- as the dominant phases. The spectroscopic properties of the compounds were analyzed using Raman and UV-vis-NIR absorption spectroscopy. The UV-vis-NIR spectra of compounds 1-5 exhibited transitions consistent with uranium in the +4 oxidation state. Clear differences in the absorption band splitting were observed and are likely attributed to differences in metal ion coordination, crystal field effects, and outer sphere interactions Overall, this work demonstrates the utility of noncovalent interactions in tuning the crystallization of various metal complexes from otherwise identical reaction solutions and provides further evidence that counterions impact the composition and structure of actinide complexes isolated in the solid state. In this way, this work affords important insight into directing and controlling the structure of actinide complexes and clusters.

Accurate and simple determination of sediment redox capacity by a modified chemical probe method: Implications to contaminant remediation

2025-06-12

Yuxi Lu , Rong Chen , Weijun Zhao +4 more | Water Research