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Title: Evaluate the role of organic acids in the protection of ligands from radiolytic degradation

Abstract

In the Advanced TALSPEAK process, the bis(2-ethylhexyl)phosphoric acid (HDEHP) extractant used in the traditional TALSPEAK process is replaced by the extractant 2-ethylhexylphosphonic acid mono-2-ethylhexyl ester (HEH[EHP]). In addition, the aqueous phase complexant and buffer used in traditional TALSPEAK is replaced with the combination of N-(2-hydroxyethyl)ethylenediamine-N,N’,N’-triacetic acid (HEDTA) and citric acid. In order to evaluate the possible impacts of gamma radiolysis upon the efficacy of the Advanced TALSPEAK flowsheet, aqueous and organic phases corresponding to the extraction section of the proposed flowsheet were irradiated in the INL test loop under an ambient atmosphere. The results of these studies conducted at INL, led INL researchers to conclude that the scarcity of values of rate constants for the reaction of hydroxyl radical with the components of the Advanced TALSPEAK process chemistry was severely limiting the interpretation of the results of radiolysis studies performed at the INL. In this work, the rate of reaction of hydroxyl radical with citric acid at several pH values was measured using a competitive pulse radiolysis technique. This report describes those results and is written in completion of milestone M3FT-16IN030102028, the goal of which was to evaluate the role of organic acids in the protection of ligands from radiolyticmore » degradation. The results reported here demonstrate the importance of obtaining hydroxyl radical reaction rate data for the conditions that closely resemble actual solution conditions expected to be used in an actual solvent extraction process. This report describes those results and is written in completion of milestone M3FT-16IN030102028, the goal of which was to evaluate the role of organic acids in the protection of ligands from radiolytic degradation.« less

Authors:
 [1];  [1];  [1]
  1. Idaho National Lab. (INL), Idaho Falls, ID (United States)
Publication Date:
Research Org.:
Idaho National Lab. (INL), Idaho Falls, ID (United States)
Sponsoring Org.:
USDOE Office of Nuclear Energy (NE)
OSTI Identifier:
1389191
Report Number(s):
INL/EXT-16-39726
DOE Contract Number:
AC07-05ID14517
Resource Type:
Technical Report
Country of Publication:
United States
Language:
English
Subject:
37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY; Aminopolycarboxylic acid; Carboxylic acid; Hydroxyl radical

Citation Formats

Miller, Anneka, Mezyk, Stehpen, and Peterman, Dean. Evaluate the role of organic acids in the protection of ligands from radiolytic degradation. United States: N. p., 2016. Web. doi:10.2172/1389191.
Miller, Anneka, Mezyk, Stehpen, & Peterman, Dean. Evaluate the role of organic acids in the protection of ligands from radiolytic degradation. United States. doi:10.2172/1389191.
Miller, Anneka, Mezyk, Stehpen, and Peterman, Dean. 2016. "Evaluate the role of organic acids in the protection of ligands from radiolytic degradation". United States. doi:10.2172/1389191. https://www.osti.gov/servlets/purl/1389191.
@article{osti_1389191,
title = {Evaluate the role of organic acids in the protection of ligands from radiolytic degradation},
author = {Miller, Anneka and Mezyk, Stehpen and Peterman, Dean},
abstractNote = {In the Advanced TALSPEAK process, the bis(2-ethylhexyl)phosphoric acid (HDEHP) extractant used in the traditional TALSPEAK process is replaced by the extractant 2-ethylhexylphosphonic acid mono-2-ethylhexyl ester (HEH[EHP]). In addition, the aqueous phase complexant and buffer used in traditional TALSPEAK is replaced with the combination of N-(2-hydroxyethyl)ethylenediamine-N,N’,N’-triacetic acid (HEDTA) and citric acid. In order to evaluate the possible impacts of gamma radiolysis upon the efficacy of the Advanced TALSPEAK flowsheet, aqueous and organic phases corresponding to the extraction section of the proposed flowsheet were irradiated in the INL test loop under an ambient atmosphere. The results of these studies conducted at INL, led INL researchers to conclude that the scarcity of values of rate constants for the reaction of hydroxyl radical with the components of the Advanced TALSPEAK process chemistry was severely limiting the interpretation of the results of radiolysis studies performed at the INL. In this work, the rate of reaction of hydroxyl radical with citric acid at several pH values was measured using a competitive pulse radiolysis technique. This report describes those results and is written in completion of milestone M3FT-16IN030102028, the goal of which was to evaluate the role of organic acids in the protection of ligands from radiolytic degradation. The results reported here demonstrate the importance of obtaining hydroxyl radical reaction rate data for the conditions that closely resemble actual solution conditions expected to be used in an actual solvent extraction process. This report describes those results and is written in completion of milestone M3FT-16IN030102028, the goal of which was to evaluate the role of organic acids in the protection of ligands from radiolytic degradation.},
doi = {10.2172/1389191},
journal = {},
number = ,
volume = ,
place = {United States},
year = 2016,
month = 8
}

Technical Report:

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