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Title: Water-soluble Schiff base-actinyl complexes and their effect on the solvent extraction of f-elements

Abstract

Conventional solvent extraction of selected f-element cations by bis(2-ethylhexyl)phosphoric acid (HDEHP) yields increased extraction from aqueous to organic solution along the series Np(V) < Cm(III) < Eu(III) < U(VI), with distribution ratios all within two orders of magnitude. However, in the presence of the water-soluble tetradentate Schiff base (N,N'-bis(5-sulfonatosalicylidene)-ethylenediamine or H 2salenSO 3), selective complexation of the two actinyl cations (Np(V) and U(VI)) resulted in an extraction order of Np(V) < U(VI) << Eu(III) < Cm(III). The extraction of neither Cm(III) or Eu(III) by HDEHP are significantly impacted by the presence of the aqueous phase Schiff base. Despite observed hydrolytic decomposition of H 2salenSO 3 in aqueous solutions, the calculated high conditional stability constant (β 11 = 26) for the complex [UO 2(salenSO 3)] 2- demonstrates its capacity for aqueous hold-back of U(VI). UV-visible-NIR spectroscopy of solutions prepared with a Np(VI) stock and H 2salenSO 3 suggest that reduction of Np(VI) to Np(V) by the ligand was rapid, resulting in a pentavalent Np complex that was substantially retained in the aqueous phase. Lastly, results from 1H NMR of aqueous solutions of H 2salenSO 3 with U(VI) and La(III), Eu(III), and Lu(III) provides additional evidence that the ligand readily chelates U(VI),more » but has only weak interactions with trivalent lanthanide ions.« less

Authors:
 [1];  [2]; ORCiD logo [3];  [3];  [1]
  1. Univ. of California, Irvine, CA (United States). Dept. of Chemical Engineering and Materials Science
  2. Univ. of California, Irvine, CA (United States). Dept. of Chemical Engineering and Materials Science; Los Alamos National Lab. (LANL), Los Alamos, NM (United States)
  3. Los Alamos National Lab. (LANL), Los Alamos, NM (United States)
Publication Date:
Research Org.:
Los Alamos National Lab. (LANL), Los Alamos, NM (United States)
Sponsoring Org.:
USDOE Laboratory Directed Research and Development (LDRD) Program; USDOE National Nuclear Security Administration (NNSA)
OSTI Identifier:
1418758
Report Number(s):
LA-UR-16-23332
Journal ID: ISSN 1477-9226; ICHBD9
Grant/Contract Number:
AC52-06NA25396; 12-LF-237294
Resource Type:
Journal Article: Accepted Manuscript
Journal Name:
Dalton Transactions
Additional Journal Information:
Journal Volume: 45; Journal Issue: 39; Journal ID: ISSN 1477-9226
Publisher:
Royal Society of Chemistry
Country of Publication:
United States
Language:
English
Subject:
37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY

Citation Formats

Hawkins, Cory A., Bustillos, Christian G., May, Iain, Copping, Roy, and Nilsson, Mikael. Water-soluble Schiff base-actinyl complexes and their effect on the solvent extraction of f-elements. United States: N. p., 2016. Web. doi:10.1039/C6DT01357K.
Hawkins, Cory A., Bustillos, Christian G., May, Iain, Copping, Roy, & Nilsson, Mikael. Water-soluble Schiff base-actinyl complexes and their effect on the solvent extraction of f-elements. United States. doi:10.1039/C6DT01357K.
Hawkins, Cory A., Bustillos, Christian G., May, Iain, Copping, Roy, and Nilsson, Mikael. 2016. "Water-soluble Schiff base-actinyl complexes and their effect on the solvent extraction of f-elements". United States. doi:10.1039/C6DT01357K. https://www.osti.gov/servlets/purl/1418758.
@article{osti_1418758,
title = {Water-soluble Schiff base-actinyl complexes and their effect on the solvent extraction of f-elements},
author = {Hawkins, Cory A. and Bustillos, Christian G. and May, Iain and Copping, Roy and Nilsson, Mikael},
abstractNote = {Conventional solvent extraction of selected f-element cations by bis(2-ethylhexyl)phosphoric acid (HDEHP) yields increased extraction from aqueous to organic solution along the series Np(V) < Cm(III) < Eu(III) < U(VI), with distribution ratios all within two orders of magnitude. However, in the presence of the water-soluble tetradentate Schiff base (N,N'-bis(5-sulfonatosalicylidene)-ethylenediamine or H2salenSO3), selective complexation of the two actinyl cations (Np(V) and U(VI)) resulted in an extraction order of Np(V) < U(VI) << Eu(III) < Cm(III). The extraction of neither Cm(III) or Eu(III) by HDEHP are significantly impacted by the presence of the aqueous phase Schiff base. Despite observed hydrolytic decomposition of H2salenSO3 in aqueous solutions, the calculated high conditional stability constant (β11 = 26) for the complex [UO2(salenSO3)]2- demonstrates its capacity for aqueous hold-back of U(VI). UV-visible-NIR spectroscopy of solutions prepared with a Np(VI) stock and H2salenSO3 suggest that reduction of Np(VI) to Np(V) by the ligand was rapid, resulting in a pentavalent Np complex that was substantially retained in the aqueous phase. Lastly, results from 1H NMR of aqueous solutions of H2salenSO3 with U(VI) and La(III), Eu(III), and Lu(III) provides additional evidence that the ligand readily chelates U(VI), but has only weak interactions with trivalent lanthanide ions.},
doi = {10.1039/C6DT01357K},
journal = {Dalton Transactions},
number = 39,
volume = 45,
place = {United States},
year = 2016,
month = 9
}

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