Diglycolamide-Based Solvent Systems in Room Temperature Ionic Liquids for Actinide Ion Extraction: A Review

Abstract

This review article gives a comprehensive account of the extraction of actinide ions using room temperature ionic liquid-based solvent systems containing diglycolamide (DGA) or functionalized DGA extractants. These extractants include multiple DGA-functionalized ligands such as tripodal DGA (T-DGA) and DGA-functionalized calix [4]arenes (C4DGA). Apart from metal ion extraction behaviour, other important features of the ionic liquid-based solvent systems such as separation behaviour, luminescence spectroscopic results, thermodynamics of extraction and radiolytic stability of the ionic liquid-based solvents are also reviewed. Results from studies on DGA-functionalized task-specific ionic liquids (TSIL) are also included in this review article.

Selective Micellar Extraction of Ultratrace Levels of Uranium in Aqueous Samples by Task Specific Ionic Liquid Followed by Its Detection Employing Total Reflection X-ray Fluorescence Spectrometry

“…This plot (given as Supporting Information Figure S6) results in two different straight lines having different slopes, thereby indicating two different extraction mechanisms of UO 2 2+ by TSIL in [Me 3 NBu]­[NTf 2 ] phase at higher and lower HNO 3 concentrations. At higher acidity (1.0–5.0 mol L –1 ) the extraction occurs via solvation or ion-pair mechanism, whereas at lower acidity ((0.1–1) × 10 –6 mol L –1 ) it follows a cation-exchange mechanism. , However, in lower acidity a plateau was observed below 1 × 10 –4 mol L –1 HNO 3 concentration, which is a typical behavior of cation-exchange extraction mechanism. In order to confirm the complexation mechanism of TSIL with UO 2 2+ ion, studies were carried out at lower (0.01 mol L –1 ) and higher (2.0 mol L –1 ) HNO 3 concentration using isothermal calorimetric titration (ICT).…”

Recovery of Rare Earth Elements (REEs) Using Ionic Solvents

“…Diglycolamides (DGAs), with their tridentate O-donating ligands, have the ability to form stable complexes with lanthanides and actinides. Therefore, diglycolamide-based systems in IL have been investigated for the recovery of such metals [139]. It was found that N,N,N ,N -tetraoctyl diglycolamide (TODGA) allows the enhancement of the extraction performance for REEs when it is diluted in [C 1 C 4 im] [NTf 2 ] in comparison to an isooctane system.…”

Complexometric titrations: new reagents and concepts to overcome old limitations

“…On the other hand, without addition of a hydrophobic cationic exchanger, dissolving the extractant into the ionic liquid can also result in a high extraction efficiency for lanthanides, still based on the cation-exchange mechanism. 58,59 Diglycolamide-functionalized specific ionic liquids with functional groups attached to the cationic part of the ionic liquid showed high extraction efficiency to actinides and lanthanides. [59][60][61] Verboom and co-workers also reported on a series of new ligands based on diglycolamides that have three functional groups at C-pivot and trialkylphenyl platforms.…”

“…58,59 Diglycolamide-functionalized specific ionic liquids with functional groups attached to the cationic part of the ionic liquid showed high extraction efficiency to actinides and lanthanides. [59][60][61] Verboom and co-workers also reported on a series of new ligands based on diglycolamides that have three functional groups at C-pivot and trialkylphenyl platforms. 62 These ligands also showed high affinity for Am(III) and Eu(III) with a 1 : 1 metal to ligand stoichiometry.…”