Liquid-liquid extraction of cerium using synergist extractant

Abstract

This work studies on the performance of synergist extractants on the extraction of Cerium (Ce) alone. Conventional extractant, 4,4,4-trifluoro-1-(2-thienyl)-1,3butanedione (HTTA) was combined with 3-methylimidazolium bis(triflouromethylsulfonyl)imide [C n mim][NTf 2 ], n=2,4 at different ratios to identify the best mixing ratio between HTTA and ionic liquid respectively. The effect of pH and temperature were also investigated on synergist extractant. Liquid-liquid extraction (LLE) was conducted by mixing synergist extractant with aqueous phase of Ce in the ratio of 1:1. The studies on pH and temperature were conducted in a range of 1.5-5.5 and 25-45 o C respectively. synergist extractant of HTTA-[C 4 mim][NTf 2 ] was found to have better extraction efficiency compared to HTTA-[C 2 mim][NTf 2 ] under the optimum pH of 4.5-5.5 and temperature of 45°C. HTTA-[C 4 mim][NTf 2 ] also exhibits better Ce extraction when the extractant was at independent mode i.e. HTTA or [C 4 mim][NTf 2 ]. In conclusion, the synergist extractant is more efficient at extraction of Ce compared to independent extractant under the pH value of 5 at 45°C.

Recovery of Rare Earth Elements (REEs) Using Ionic Solvents

“…In these cases, metal ions are complexed by the conjugate bases. Among these extractants, numerous studies have been dedicated to the use of the beta-diketone HTTA in imidazolium-based IL ([C 1 C n im] [NTf 2 ]) [114][115][116][117][118] − complexes can be encountered [114]. The stoichiometry of extracted complexes, such as the Ln(TTA) 4 − anionic complex, was confirmed by emission profiles and spectrophotometric titration respectively for Eu 3+ /HTTA and Nd 3+ /HTTA complexes [115].…”

“…The role of the IL anion with regard to Ln chelates and the extraction mechanism has been evidenced for the bis(trifluoromethanesulfonyl)imide anion (NTf 2 ) [116], as well as nonafluoro-1-butanesulfonate (CF 3 (CF 2 ) 3 SO 3 − ) [117]. The efficiency of HTTA has thus been demonstrated for various REEs [118]; other beta-diketones, such as benzoylacetone (HBA), also show the interest of this type of extractant. This aptitude for REE extraction has also been studied within the implementation of synergistic systems in combination with neutral extractants.…”

Extraction of light, medium and heavy rare-earth elements using synergist extractants developed from ionic liquid and conventional extractants

“…In the past few years, synergist extractants have revolutionised the conventional extractants by reforming the extractants either by merging two or more extractants together [27] or restructuring the organic compound of the extractants [28] to develop extractants with better extraction capability and durability [29e34]. Synergist extractants have the potential to overcome typical issues in solvent extraction such as poor metal extraction, poor selectivity of desired REE and the competition of REE separation from other minerals observed while using conventional extractants.…”