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Title: Separation of americium from europium using 3,3'-dimethoxy-phenyl-bis-1,2,4-triazinyl-2,6-pyridine

Abstract

Development of liquid-liquid separation processes for the effective removal of the minor actinide Am(III) from used nuclear fuel using ligand-based strategies continues to be an area of significant research focus. The current investigation demonstrates the efficacy of a nitrogen-based bis-triazinyl pyridine (BTP) derivative to selectively extract Am(III) from nitric acid solutions containing light lanthanides. The performance of 3,3’-dimethoxy-phenyl-bis-1,2,4-triazinyl-2,6- pyridine (MOB-BTP) was compared to that of a camphor substituted BTP (CA-BTP). The results of this investigation demonstrate the novel 3,3’-methoxy-BTP extractant dissolved in a polar diluent was a more efficient extractant for Am(III) at a lower concentration than CA-BTP under comparable conditions.

Authors:
 [1];  [2];  [2];  [2];  [2]; ORCiD logo [3]
  1. Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)
  2. Tennessee Technological Univ., Cookeville, TN (United States). Dept. of Chemistry
  3. Oak Ridge National Laboratory, Oak Ridge, Tennessee, USA
Publication Date:
Research Org.:
Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)
Sponsoring Org.:
USDOE Office of Nuclear Energy (NE); National Science Foundation (NSF)
OSTI Identifier:
1393868
Grant/Contract Number:
AC05-00OR22725; NSF-RUI 9970016
Resource Type:
Journal Article: Accepted Manuscript
Journal Name:
Separation Science and Technology
Additional Journal Information:
Journal Volume: N/A; Journal ID: ISSN 0149-6395
Publisher:
Taylor & Francis
Country of Publication:
United States
Language:
English
Subject:
37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY; Americium europium separation; BTP; nitrogen donor extractant; nuclear fuel cycle; solvent extraction

Citation Formats

Hill, Talon G., Chin, Ai Lin, Tai, Serene, Carrick, Jesse D., Ensor, Dale D., and Delmau, Lætitia H.. Separation of americium from europium using 3,3'-dimethoxy-phenyl-bis-1,2,4-triazinyl-2,6-pyridine. United States: N. p., 2017. Web. doi:10.1080/01496395.2017.1304419.
Hill, Talon G., Chin, Ai Lin, Tai, Serene, Carrick, Jesse D., Ensor, Dale D., & Delmau, Lætitia H.. Separation of americium from europium using 3,3'-dimethoxy-phenyl-bis-1,2,4-triazinyl-2,6-pyridine. United States. doi:10.1080/01496395.2017.1304419.
Hill, Talon G., Chin, Ai Lin, Tai, Serene, Carrick, Jesse D., Ensor, Dale D., and Delmau, Lætitia H.. Wed . "Separation of americium from europium using 3,3'-dimethoxy-phenyl-bis-1,2,4-triazinyl-2,6-pyridine". United States. doi:10.1080/01496395.2017.1304419. https://www.osti.gov/servlets/purl/1393868.
@article{osti_1393868,
title = {Separation of americium from europium using 3,3'-dimethoxy-phenyl-bis-1,2,4-triazinyl-2,6-pyridine},
author = {Hill, Talon G. and Chin, Ai Lin and Tai, Serene and Carrick, Jesse D. and Ensor, Dale D. and Delmau, Lætitia H.},
abstractNote = {Development of liquid-liquid separation processes for the effective removal of the minor actinide Am(III) from used nuclear fuel using ligand-based strategies continues to be an area of significant research focus. The current investigation demonstrates the efficacy of a nitrogen-based bis-triazinyl pyridine (BTP) derivative to selectively extract Am(III) from nitric acid solutions containing light lanthanides. The performance of 3,3’-dimethoxy-phenyl-bis-1,2,4-triazinyl-2,6- pyridine (MOB-BTP) was compared to that of a camphor substituted BTP (CA-BTP). The results of this investigation demonstrate the novel 3,3’-methoxy-BTP extractant dissolved in a polar diluent was a more efficient extractant for Am(III) at a lower concentration than CA-BTP under comparable conditions.},
doi = {10.1080/01496395.2017.1304419},
journal = {Separation Science and Technology},
number = ,
volume = N/A,
place = {United States},
year = {Wed Mar 22 00:00:00 EDT 2017},
month = {Wed Mar 22 00:00:00 EDT 2017}
}

Journal Article:
Free Publicly Available Full Text
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  • New bifunctional and trifunctional organophosphorus ligands, 2-[(bis(2-ethylhexyl)phosphino)methyl]pyridine N,P-dioxide, DEH(MNOPO), and 2,6-bis[(bis(2-ethylhexyl)phosphino)methyl]pyridine N,P,P'-trioxide, TEH(NOPOPO), have been synthesized. In contrast with previously reported phenyl derivatives, the increased solubility of these ligands in normal paraffinic hydrocarbon solvents make them attractive reagents for actinide partitioning. While the bifunctional reagent DEH(MNOPO) interacts with Eu{sup 3+} and Am{sup 3+} comparatively weakly, the trifunctional TEH(NOPOPO) exhibits moderate to high ability to transfer the trisnitrato complexes of these ions into n-dodecane from acidic aqueous solutions. We report here the details of TEH(NOPOPO) and DEH(MNOPO) preparation and of their ability to extract HNO{sub 3}, Am(NO{sub 3}){sub 3}, and Eu(NO{submore » 3}){sub 3} into paraffinic hydrocarbons. The trifunctional TEH(NOPOPO) can extract up to two molecules of HNO{sub 3}. The dominant extracted species for both Am(NO{sub 3}){sub 3} and Eu(NO{sub 3}){sub 3} has two TEH(NOPOPO) ligands associated over the range of temperatures 10-40 C. From the variation in the equilibrium coefficients for the phase transfer reactions as a function of temperature, we have calculated the enthalpies and entropies for extraction of HNO{sub 3}, Am(NO{sub 3}){sub 3}, and Eu(NO{sub 3}){sub 3} into n-dodecane. Each metal nitrate is transferred into the organic phase in an exothermic process but opposed by an unfavorable (negative) entropy. The thermodynamic data are interpreted to indicate that the pyridine N-oxide is apparently a significantly weaker donor group for these metal ions than the phosphine oxides.« less
  • Bis-triazine phenanthrolines have shown great promise for f-block metal separations, attributable to their highly preorganized structure, nitrogen donors, and more enhanced covalent bonding with actinides over lanthanides. However, their limited solubility in traditional solvents remains a technological bottleneck. Here in this paper we report our recent work using a simple 2,9-bis(triazine)-1,10-phenanthroline (Me-BTPhen) dissolved in an ionic liquid (IL), demonstrating the efficacy of IL extraction systems for the selective separation of americium from europium, achieving separation factors in excess of 7500 and selectively removing up to 99% of the americium. Characterization of the coordination environment was performed using a combination ofmore » X-ray absorption fine structure spectroscopy (XAFS) and density functional theory (DFT) calculations.« less
  • The liquid/liquid extraction of Am(III) from hydrochloric acid solutions with chloroform solutions of 2,6-bis[(diphenylphosphino)methyl]pyridine N,P,P{prime}-trioxide (ENOPOPO) is described. ENOPOPO exhibits modest extraction ability for americium(III) (D{sub Am} = 2.2 at 5 M HCl) and can be efficiently back extracted from the organic phase at 0.1 M HCl. The ligand dependency data suggest that three ligand molecules are coordinated to the americium in the extraction complex. Additional aspects of the extraction mechanism are described.
  • One method of treatment under consideration for processing of high-level radioactive fuel materials involves nuclear incineration. The success of the approach, in part, depends on the separation of minor actinides Am and Cm from the dominant actinides U and Pu prior to incineration. Therefore, there is fundamental interest, as well as practical demands, for the development of new selective coordination and separations chemistry for these species in aqueous solutions. Several families of ligands such as carbamoylmethylphophonates (CMP), (RO)2P(O)CH2C(O)NR2, carbamoylmethylphophine oxides (CMPO), R2P(O)CH2C(O)NR2, and alkyl malonamides, [RR'NC(O)2''H], have attracted the greatest attention as selective actinide ion chelators due in part tomore » their stability toward strong radiation fields, as well as their ability to function in contact with the acidic aqueous solutions typically used to handle the actinide ions. In our group, we have been developing another family of ligands that offer promising performance in actinide separations: phosphinomethylpyridine-N-oxides, NOPO and NOPOPO.« less
  • The title ligand is obtained in two steps with high overall yield, and is soluble in aromatic solvents, making its liquid-liquid extraction performance of potential interest. The ligand forms a stable 1:1 coordination complex with Er(NO3)3 and the molecular structure was determined by single crystal x-ray diffraction methods. The Er(III) ion is chelated by one tridentate ligand and three bidentate nitrate groups. The structural results are discussed in the context of complexes formed by related ligands.