title: Extraction behavior of lanthanides using a diglycolamide derivative TODGA in ionic liquids.
abstract: Liquid-liquid extraction of lanthanides from aqueous solutions into ionic liquids (ILs) has been investigated using N,N,N',N'-tetra(n-octyl)diglycolamide (TODGA) as an extractant, and compared with that in the isooctane system. Application of ILs as the extracting phase provided unprecedented enhancement of the extraction performance of TODGA for lanthanides compared with that of the isooctane system. Slope analysis confirmed that TODGA in ILs formed a 1:3 complex with La3+, Eu3+, or Lu3+. On the other hand, the molar ratios of species extracted into isooctane were 1:3 for La3+ or 1:4 for Eu3+ and Lu3+, depending on the atomic number of the lanthanide. The transfer of lanthanides with TODGA into ILs proceeded via a cation-exchange mechanism, in contrast to ion pair extraction in the isooctane system. Furthermore, we clarified that TODGA provided selectivity for the middle lanthanides in the ILs systems, but heavier lanthanides in the isooctane system.
authors.affiliation: Division of Environment and Radiation Sciences, Nuclear Science and Engineering Directorate, Japan Atomic Energy Agency, Tokai-mura, Ibaraki 319-1195, Japan. shimojo.kojiro@jaea.go.jp
authors.forename: Kojiro
authors.initials: K
authors.lastname: Shimojo
authors.forename: Kensuke
authors.initials: K
authors.lastname: Kurahashi
authors.forename: Hirochika
authors.initials: H
authors.lastname: Naganawa
mesh_terms: D006016:Glycolates / Q000737:chemistry*; D052578:Ionic Liquids / Q000737:chemistry*; D028581:Lanthanoid Series Elements / Q000737:chemistry*; D015394:Molecular Structure; D017942:Nitric Acid / Q000737:chemistry; D009942:Organometallic Compounds / Q000138:chemical synthesis* / Q000737:chemistry; D015203:Reproducibility of Results; D012995:Solubility; D013464:Sulfuric Acids / Q000737:chemistry
chemical_list: D006016:Glycolates; D052578:Ionic Liquids; D028581:Lanthanoid Series Elements; D009942:Organometallic Compounds; D013464:Sulfuric Acids; C520173:tetra-n-octyldiglycolamide; D017942:Nitric Acid; C033158:sulfuric acid