Chelate Extraction of Metals into Ionic Liquids

Hirayama, Naoki

doi:10.15261/serdj.18.1

Cited by 40 publications

(14 citation statements)

References 107 publications

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“…In analogous systems employing thenyltrifluoroacetone (HTTA) as extractant to extract metals (M) in ILs, the authors found that the extraction is favored using more hydrophobic ILs [37]. This is not true in our case, because [C 2 mim][Tf 2 N] is less hydrophobic than ammonium and phosphonium ILs.…”

Section: Effect Of the Il Compositionmentioning

confidence: 59%

Solvent extraction of lithium ions using benzoyltrifluoroacetone in new solvents

Masmoudi

Zante

Trébouet

et al. 2021

Separation and Purification Technology

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The chelating agent benzoyltrifluoroacetone (HBTA) was used for the extraction of lithium ions from alkaline solutions. Aiming to develop an eco-friendly extraction system, hydrophobic room-temperature ionic liquids (RTILs) were investigated as diluents. The influence of several experimental parameters on the extraction efficiency was investigated, including, aqueous pH, the nature of counter-ion, and the synergistic agent effect. It was found that contrary to the classical systems using molecular organic solvents, HBTA alone dissolved in 1-ethl-3-Alkylimidazolium bis(trifluoromethylsulfonyl)imide ([C 2 mim][Tf 2 N]) ionic liquid can highly extract lithium without the need of a synergistic agent such as tri(noctyl)phosphine oxide (TOPO). The extraction mechanism was studied using the electroneutrality principle based on concentration measurements of the IL constituent ions and deprotonated HBTA (BTA -). It was found that a neutral lithium-extractant complex is extracted to the IL phase. The system combining HBTA and [C 6 mim][Tf 2 N] ionic liquid has high selectivity for lithium over sodium but poor selectivity over calcium. We have shown also that a high stripping ratio can be obtained using relatively concentrated hydrochloric acid. Finally, it was found that the use of deep eutectic solvents (DESs) as diluents is much less efficient compared with ILs.

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Section: Effect Of the Il Compositionmentioning

confidence: 59%

Solvent extraction of lithium ions using benzoyltrifluoroacetone in new solvents

Masmoudi

Zante

Trébouet

et al. 2021

Separation and Purification Technology

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“…In the removal of copper ions by solvent extraction with IL and beta‐diketones, the expected mechanism is a cation exchange. However, if this is the mechanism, which can be verified in conventional organic solvents, it must be proved in ILs, since different complexation modes have been observed . Indeed Cu(II)‐TFA complex formation in ILs may generate three type of neutral or ionic species ( n molecules of copper react with m molecules of TFA): Cu(TFA) n with n = 2; Cu(TFA) n (2‐ n )+ with n < 2; and Cu(TFA) n ( n ‐2)‐ with n > 2, where Cu(II) complexes with m molecules of TFA release n protons.…”

Section: Methodsmentioning

confidence: 99%

“…Indeed Cu(II)‐TFA complex formation in ILs may generate three type of neutral or ionic species ( n molecules of copper react with m molecules of TFA): Cu(TFA) n with n = 2; Cu(TFA) n (2‐ n )+ with n < 2; and Cu(TFA) n ( n ‐2)‐ with n > 2, where Cu(II) complexes with m molecules of TFA release n protons. Previous reports in the literature described the extraction of Cu(II) by means of [bmim][Tf 2 N] and [bmim][PF 6 ] containing Htta (4,4,4‐trifluoro‐1‐(2‐thienyl)‐1,3‐butanedione) according to the formation of a neutral complex. In this way, we have taken into account this assumption to verify the complex formation mechanism in our system.…”

Section: Methodsmentioning

confidence: 99%

Copper removal from aqueous solutions by means of ionic liquids containing a β‐diketone and the recovery of metal complexes by supercritical fluid extraction

Sepúlveda

Romero

Sánchez

2014

J of Chemical Tech & Biotech

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BACKGROUND: This work is focused on the removal of Cu(II) ions from aqueous solutions by means of different hydrophobic imidazolium-based ionic liquids containing 1,1,1-trifluoro-2,4-pentanedione (TFA) as extractant and the subsequent extraction of the metal complexes formed in the IL by means of supercritical fluid extraction. RESULTS: Solutions containing between 250 and 500 mg L -1 of Cu(II) ions were contacted with [bmim][PF 6 ], [hmim][PF 6 ] and [bmim][Tf2 N] containing TFA. After liquid-liquid extraction, both phases were analysed, verifying the formation of neutral complex Cu(TFA) 2 as the predominant extraction mechanism in [bmim][PF 6 ] and [bmim][Tf 2 N]. Meanwhile, the extraction of Cu(II) in [bmim][PF 6 ] was strongly influenced by the direct interaction between the metal ion and the IL. ILs used in L-L extractions were regenerated using supercritical CO 2 at 18 MPa and 40 ∘ C. [bmim][Tf 2 N] showed the highest accumulative extraction percentage (≈ 80%) after sequential loads of Cu(II) ions. CONCLUSION: From these tests, [bmim][Tf 2 N] was the solvent that showed the best performance in terms of accumulative extraction and recycling capacity in sequential extraction cycles mediated by regeneration with supercritical CO 2 . This study demonstrates that this process could be considered an alternative separation technique for metal ions using green solvents, and with extractant requirements lower than in conventional solvent extraction operations.

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“…Since the pioneering work of Dai et al [92] highlighting the potential of ILs for solvent extraction in the context of metal recovery, many studies have been developed showing their potential in terms of efficiency in comparison to classical organic solvents [93].…”

Section: Solvent Extraction Processesmentioning

confidence: 99%

Recovery of Rare Earth Elements (REEs) Using Ionic Solvents

et al. 2021

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Rare earth elements (REEs) are becoming more and more significant as they play crucial roles in many advanced technologies. Therefore, the development of optimized processes for their recovery, whether from primary resources or from secondary sources, has become necessary, including recovery from mine tailings, recycling of end-of-life products and urban and industrial waste. Ionic solvents, including ionic liquids (ILs) and deep-eutectic solvents (DESs), have attracted much attention since they represent an alternative to conventional processes for metal recovery. These systems are used as reactive agents in leaching and extraction processes. The most significant studies reported in the last decade regarding the recovery of REEs are presented in this review.

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Chelate Extraction of Metals into Ionic Liquids

Cited by 40 publications

References 107 publications

Solvent extraction of lithium ions using benzoyltrifluoroacetone in new solvents

Solvent extraction of lithium ions using benzoyltrifluoroacetone in new solvents

Copper removal from aqueous solutions by means of ionic liquids containing a β‐diketone and the recovery of metal complexes by supercritical fluid extraction

Recovery of Rare Earth Elements (REEs) Using Ionic Solvents

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