scholarly journals Uranyl Speciation in the Presence of Specific Ion Gradients at the Electrolyte/Organic Interface

2021 ◽  
Author(s):  
Nitesh Kumar ◽  
Michael J. Servis ◽  
Aurora Clark
Keyword(s):  
Environmental Remediation ◽  
Spent Nuclear Fuel ◽  
Outer Sphere ◽  
Depletion Region ◽  
Association Constants ◽  
Liquid Interface ◽  
Interfacial Region ◽  
Solvation Dynamics ◽  
Ion Concentrations ◽  
Nitrate Complexes

<p>Uranyl (UO2+ 2 ) speciation at the liquid/liquid interface is an essential aspect of the mech?anism that underlies its extraction as part of spent nuclear fuel reprocessing schemes and environmental remediation of contaminated legacy waste sites. Of particular importance is a detailed perspective of how changing ion concentrations at the liquid interface alter the distribu?tion of hydrated uranyl ion and its interactions with complexing electrolyte counterions relative to the bulk aqueous solution. In this work, classical molecular dynamics simulations have ex?amined uranyl in bulk LiNO3(aq) and in the presence of a hexane interface. UO2+ 2 is observed to have both direct coordination with NO− 3 and outer-sphere interactions via solvent-separated ion-pairing (SSIP), whereas the interaction of Li+ with NO− 3 (if it occurs) is predominantly as a contact ion-pair (CIP). The variability of uranyl interactions with nitrate is hypothesized to prevent dehydration of uranyl at the interface, and as such the cation concentration is un?perturbed in the interfacial region. However, Li+ loses waters of solvation when it is present in the interfacial region, an unfavorable process that causes a Li+ depletion region. Although significant perturbations to ion-ion interactions, solvation, and solvation dynamics are observed in the interfacial region, importantly, this does not change the association constants of uranyl with nitrate. Thus, the experimental association constants, in combination with knowledge of the interfacial ion concentrations, can be used to predict the distribution of interfacial uranyl nitrate complexes. The enhanced concentration of uranyl dinitrate at the interface, caused by excess adsorbed NO− 3 , is highly relevant to extractant ligand design principles as such nitrate complexes are the reactants in ligand complexation and extraction events. </p>

scholarly journals Uranyl Speciation in the Presence of Specific Ion Gradients at the Electrolyte/Organic Interface

2021 ◽  
Author(s):  
Nitesh Kumar ◽  
Michael J. Servis ◽  
Aurora Clark
Keyword(s):  
Environmental Remediation ◽  
Spent Nuclear Fuel ◽  
Outer Sphere ◽  
Depletion Region ◽  
Association Constants ◽  
Liquid Interface ◽  
Interfacial Region ◽  
Solvation Dynamics ◽  
Ion Concentrations ◽  
Nitrate Complexes

<p>Uranyl (UO2+ 2 ) speciation at the liquid/liquid interface is an essential aspect of the mech?anism that underlies its extraction as part of spent nuclear fuel reprocessing schemes and environmental remediation of contaminated legacy waste sites. Of particular importance is a detailed perspective of how changing ion concentrations at the liquid interface alter the distribu?tion of hydrated uranyl ion and its interactions with complexing electrolyte counterions relative to the bulk aqueous solution. In this work, classical molecular dynamics simulations have ex?amined uranyl in bulk LiNO3(aq) and in the presence of a hexane interface. UO2+ 2 is observed to have both direct coordination with NO− 3 and outer-sphere interactions via solvent-separated ion-pairing (SSIP), whereas the interaction of Li+ with NO− 3 (if it occurs) is predominantly as a contact ion-pair (CIP). The variability of uranyl interactions with nitrate is hypothesized to prevent dehydration of uranyl at the interface, and as such the cation concentration is un?perturbed in the interfacial region. However, Li+ loses waters of solvation when it is present in the interfacial region, an unfavorable process that causes a Li+ depletion region. Although significant perturbations to ion-ion interactions, solvation, and solvation dynamics are observed in the interfacial region, importantly, this does not change the association constants of uranyl with nitrate. Thus, the experimental association constants, in combination with knowledge of the interfacial ion concentrations, can be used to predict the distribution of interfacial uranyl nitrate complexes. The enhanced concentration of uranyl dinitrate at the interface, caused by excess adsorbed NO− 3 , is highly relevant to extractant ligand design principles as such nitrate complexes are the reactants in ligand complexation and extraction events. </p>

Methodological and Practical Bases of Providing Information Support to Activities on Environmental Remediation of the Spent Nuclear Fuel and Radioactive Waste Temporary Storage Facility in Gremikha

2011 ◽  
Author(s):  
D. B. Stepennov ◽  
A. P. Varnavin ◽  
A. A. Zakharchev ◽  
L. Pillette-Cousin
Keyword(s):  
Radioactive Waste ◽  
Nuclear Fuel ◽  
Environmental Remediation ◽  
Spent Nuclear Fuel ◽  
Public Information ◽  
Operating Experience ◽  
Information Support ◽  
Research Centre ◽  
Storage Facility ◽  
Temporary Storage

Remediation of a spent nuclear fuel (SNF) and radioactive waste (RW) temporary storage facility is a multifaceted process that includes a number of stages, such as development of a remediation programme, performance of comprehensive engineering and radiological survey, development of a remediation design, removal of SNF and RW up to the site cleanup. At any stage of the remediation, making of justified decisions is ensured by availability and completeness of associated information. Huge amount of information has to be managed. Therefore an information analysis system (IAS) was developed by the National Research Centre «Kurchatov Institute» within the framework of the project for environmental remediation of the SNF and RW temporary storage facility in Gremikha with financial and technical support provided by France (CEA) and the Russian Federation (Rosatom). The IAS accumulates all information about the project: technical and radiological characteristics of objects/facilities, cartographic information, documentation, data on the project participants, technologies and equipment involved. The IAS architecture includes the following functional subsystems: data management, data analytical processing, project management, geoinformation, 3D modeling, and public information. The IAS allows developers and performers of environmental remediation of the SNF and RW temporary storage facility in Gremikha to fulfill tasks arising at all stages of the work. The IAS operating experience can be transferred for use during surveys and remediation of any radiation hazardous facilities.

Outer-sphere and inner-sphere interactions in the formation of metal-ion nitrate complexes

1978 ◽  
Vol 23 (12) ◽  
pp. 1383-1386 ◽  
Author(s):  
Donald F.C. Morris ◽  
John D. MacCarthy ◽  
Robert J. Newton
Keyword(s):  
Metal Ion ◽  
Outer Sphere ◽  
Inner Sphere ◽  
Nitrate Complexes

scholarly journals Radio Ecological Problems of Russia’s Arctic Seas Environmental Remediation

10.12737/6631 ◽  
2014 ◽  
Vol 3 (6) ◽  
pp. 12-18
Author(s):  
Хвостова ◽  
Marina Khvostova
Keyword(s):  
Environmental Remediation ◽  
Spent Nuclear Fuel ◽  
Arctic Region ◽  
The Arctic ◽  
Problem Solution ◽  
Human Beings ◽  
Nuclear Submarine ◽  
Arctic Seas ◽  
Complex Surveys ◽  
Radiation Sources

Some questions related to the Northern Sea Route status are considered in this paper. An analysis of radiation sources influence on environment, biota and human beings in the Arctic region has been carried out, and stages of this influence formation have been allocated. The world practice of ocean disposal is considered, and the information on nuclear and radiation hazardous objects dumped in the northwest Arctic seas has been submitted. The questions connected with lifting of the nuclear submarine K-27 dumped in the Kara Sea and the nuclear submarine “Komsomolets” sunken in the Norwegian Sea have been stated. Data on a modern radio ecological situation in places of dumped nuclear and radiation hazardous objects have been submitted. Such option of marine environment remediation as dumped/sunken objects lifting has been considered. An analysis of existing Russian technologies for lifting of the dumped/sunken objects has been carried out. The conclusions are drawn that the sunken and dumped objects containing spent nuclear fuel and radioactive waste, don´t constitute now real radio ecological danger to the population and environment, but they should be considered as sources of potential danger, whose scales and consequences will depend on protective barriers condition and mechanisms of further migration of radioactive materials in marine ecosystems. Regular complex surveys of the most potentially hazardous dumped/sunken objects’ status during joint international scientific and research expeditions should be a first step towards this problem solution.

Solvation Dynamics of HEHEHP Ligand at the Liquid–Liquid Interface

2018 ◽  
Vol 122 (22) ◽  
pp. 5999-6006 ◽  
Author(s):  
An T. Ta ◽  
Govind A. Hegde ◽  
Brian D. Etz ◽  
Anna G. Baldwin ◽  
Yuan Yang ◽  
...  
Keyword(s):  
Liquid Interface ◽  
Solvation Dynamics

Nitrate Complexes of Neptunium(V) with Alkali Metal Cations in the Outer Sphere

2020 ◽  
Vol 62 (2) ◽  
pp. 161-169 ◽  
Author(s):  
I. A. Charushnikova ◽  
M. S. Grigor’ev ◽  
A. M. Fedoseev ◽  
A. A. Bessonov ◽  
K. A. Lysenko
Keyword(s):  
Alkali Metal ◽  
Metal Cations ◽  
Outer Sphere ◽  
Alkali Metal Cations ◽  
Nitrate Complexes
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