Feed phase salting agent prevails the absence of organic phase Ligand: A sustainable extraction process for Eu(III)/Am(III) in an undiluted phosphonium ionic liquid

Extraction and Selective Separation of ZrIV from LnIII/AnIII Using an Undiluted Phosphonium Ionic Liquid

Solvent extraction of Zr(IV) in an undiluted phosphonium based ionic liquid (IL) and its selective separation from Ln(III) and An(III) has been investigated in the present study. Eu(III)/Am(III) were chosen as the representative Ln(III)/An(III). Tri(hexyl)tetradecylphosphonium nitrate ([P66614][NO3]) was chosen as IL phase and the feed phase was nitric acid containing the target metal ions. The extraction process was accomplished at different experimental parameters such as the concentration of initial nitric acid, initial feed metal concentration and equilibration time to explore the extractability of the proposed IL towards Zr(IV). The efficient extraction of Zr(IV) without any external ligand in IL phase and negligible extraction of Eu(III)/Am(III) were distinctly discerned leading to noteworthy separation factors for Zr(IV). The loading experiment revealed a noticeable growth of equilibrium concentrations of Zr(IV) in IL phase while that of Eu(III) was very less irrespective of the initial feed concentration. The association of two IL moieties in the complex formation process has been inferred. Nitrate ion was found to be superior as IL anion in terms of metal loading in comparison to other anions. Thermodynamics of extraction and the stripping of the loaded Zr(IV) from IL phase using a suitable stripping solution have also been investigated.

Ligand Effect on Physicochemical Properties of Ionic Liquid

In the solvent extraction process, the importance of an extractant (or ligand) and a diluent is inferred from their respective physicochemical properties. We have brought together all the recent results reported on the mixture of different extractants dissolved in a well-known ionic liquid diluent: 1-butyl-3-methylimidazolium bis(trifluoromethanesulfonyl)imide ([C₄ mim][NTf₂ ]) in the form of a review and aimed to emphasize the role of ligand polarity and structure on the physicochemical properties of an ionic liquid (IL) diluent. Some of the most important properties such as dynamic viscosity (η), absolute density ( ρ ${{\rm{{\rm \rho} }}}$ ), energy of activation (E_a ), coefficient of thermal expansion (α), phase separation time (PST), refractive index (n), etc., have been discussed meticulously in the paper. The effect of ligand structure on the aggregation behaviour of IL phase and the physicochemical properties of gamma irradiated solvent phases containing different ligands and their solution with IL phase also have been deliberated in detail.