Homogeneous liquid-liquid extraction of U(VI) from HNO3 aqueous solution to betainium bis(trifluoromethylsulfonyl)imide ionic liquid and recovery of extracted U(VI)

Takahiro Mori, Koichiro Takao, Kotoe Sasaki, Tomoya Suzuki, Tsuyoshi Arai, Yasuhisa Ikeda

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In order to examine the applicability of a thermomorphic ionic liquid, betainium bis(trifluoromethylsulfonyl)imide ([Hbet][Tf2N]), for the decontamination of solid wastes contaminated with uranium, we have studied fundamental extraction behavior of U(VI) from HNO3 aqueous solutions to [Hbet][Tf2N] phases using a homogeneous liquid-liquid extraction method. As a result, it was found that the U(VI) species are extracted with relatively high distribution ratios (D >1) in low acidic condition without any additional extractant, and proposed that the U(VI) species are extracted through the exchange reaction between [Hbet]+ and [UO2(bet)]2+. The complex formation of [UO2(bet)]2+ was found to play an important role in the extraction, because the U(VI) species were not extracted with trimethylpropylammonium bis(trifluoromethylsulfonyl)imide ([TMPA][Tf2N]) without any functional groups. We also examined the recovery method of U(VI) species from the [Hbet][Tf2N] phase. As a result, it was found that the precipitation of uranyl peroxide with the addition of H2O2 aqueous solution is the useful method for recovering U(VI) species.

Original languageEnglish
JournalSeparation and Purification Technology
Publication statusPublished - 2014 Sep 30



  • Decontamination
  • Extraction
  • Ionic liquid
  • UCST
  • Uranium

ASJC Scopus subject areas

  • Analytical Chemistry
  • Filtration and Separation

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