A striking effect of ionic-liquid anions in the extraction of Sr2+ and Cs+ by dicyclohexano-18-crown-6

Journal Article · Sun Jan 01 00:00:00 EST 2006 · Solvent Extraction and Ion Exchange

DOI:https://doi.org/10.1080/07366290500388624· OSTI ID:1098197

Luo, Huimin ^[1]; Dai, Sheng ^[1]; Bonnesen, Peter V ^[1]; Haverlock, Tamara ^[1]; Moyer, Bruce A ^[1]; Buchanan, III, A C ^[1]

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1. ORNL

The nature of the ionic-liquid (IL) anion has been found to have a remarkable effect on the solvent extraction of Sr2+ and Cs+ by dicyclohexano-18-crown-6 dissolved in ionic liquids. In particular, the extraction efficiency increases with the hydrophobicity of the IL anion as reflected by the solubility in water of ILs having a common cation. Since a cation-exchange mechanism is operating in these systems, the influence of the IL anion is in large part attributable to an expected Le Chatelier effect in which a greater aqueous concentration of IL cation, obtained when using an IL anion of lower hydrophobicity, opposes cation exchange. This dependence is opposite to that found for IL cations, indicating a significant advantage of using ILs with hydrophobic anions for cation extraction. Furthermore, the extraction selectivity for Sr2+ over Na+, K+, and Cs+ can be significantly improved through the use of hydrophobic anions for the ILs containing 1-ethyl-3-methylimidazolium or 1-butyl-3-methylimidazolium cations.

• Research Organization: Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)
• Sponsoring Organization: USDOE Office of Nuclear Energy (NE)
• DOE Contract Number: DE-AC05-00OR22725
• OSTI ID: 1098197
• Journal Information: Solvent Extraction and Ion Exchange, Vol. 24, Issue 1; ISSN 0736--6299
• Country of Publication: United States
• Language: English