Thallium Transfer from Hydrochloric Acid Media into Pure Ionic Liquids

Abstract

Pure hydrophobic ionic liquids are known to extract metallic species from aqueous solutions. In this work we have systematically investigated thallium (Tl) extraction from aqueous hydrochloric acid (HCl) solutions into six pure fluorinated ionic liquids, namely imidazolium- and pyrrolidinium-based ionic liquids with bis(trifluoromethanesulfonyl)imide and bis(fluorosulfonyl)-imide anions. The dependence of the Tl extraction efficiency on the structure and composition of the ionic liquid ions, metal oxidation state, and initial metal and aqueous acid concentrations have been studied. Tl concentrations were on the order of picomolar (analyzed using radioactive tracers) and millimolar (analyzed using inductively coupled plasma mass spectrometry). The extraction of the cationic thallium species Tl(+) is higher for ionic liquids with more hydrophilic cations, while for the TlX(z)(3-z) anionic species (where X = Cl(-) and/or Br(-)), the extraction efficiency is greater for ionic liquids with more hydrophobic cations. The highest distribution value of Tl(III) was approximately 2000. An improved mathematical model based on ion exchange and ion pair formation mechanisms has been developed to describe the coextraction of two different anionic species, and the relative contributions of each mechanism have been determined.

Mutual solubility of water and hydrophobic ionic liquids in the presence of hydrochloric acid

“…35,41,56 The effect of the salts [C 4 mim]Cl and Li[Tf 2 N], containing common cationic or anionic parts with the [C 4 mim][Tf 2 N] ionic liquid, was investigated in this work because the introduction of these compounds in the aqueous acidic phase is widely used for understanding the extraction mechanism of metallic ions in ILbased biphasic systems. 2,29,57 mim]Cl salts dissolved in the aqueous acidic phase on the water uptake in ILs is more pronounced at higher aqueous HCl concentrations. These results will be discussed below.…”

Solvent extraction of rare earths elements from nitrate media in DMDOHEMA/ionic liquid systems: performance and mechanism studies

“…17,18 Similarly, the alkyl chain length carried by the IL cation has oen a strong inuence on extraction. 19,20 These two essential parameters were therefore studied in details in this study for REE extraction with a malonamide extractant solubilized in two ionic liquids [EBPip + ] [NTf 2 À ] and…”

Utilizing Recyclable Task-Specific Ionic Liquid for Selective Leaching and Refining of Scandium from Bauxite Residue

“…This IL is a weak Brønsted acidic IL due to the carboxyl group attached to its cation, [Hbet] + , that is known to coordinate with various metal ions [9]. Since its development from Nockemann et al in 2006 [10], [Hbet][Tf 2 N], has been extensively investigated in different metallurgical processes for dissolution and/or extraction of Sc, REEs [11][12][13][14][15][16][17][18], In [19,20], Th [20], uranyl species [21][22][23], Au [24] and PGMs [25,26].…”