Table 1 Summary of the literature reported on the use of ionic liquids in solvent extraction of metals.

⁴⁶

Cyphos IL 101 (Cy IL 101)

Cyphos IL 102 (Cy IL 102)

Gold

pH of 9, A/O ratio of 2, and concentration of IL of 1.25 mmol/L

⁴⁷

ionic liquid methyltrioctylammonium chloride, [MTOA⁺][Cl⁻]

Zn, Cd, and Fe

Contact time of 5 min and Temperature of 303.15 K

²²

R₄PSCN

Cu

Contact time of 5 min, pH of 0.75, Temperature of 25 ⁰C, and phase ratio (A: O) of 1:1

⁴⁸

R₄ND and R₄NCY

Mo

pH of 2.0, A: O of 5:1,

⁴⁹

trialkylmethylammonium di(2-ethylhexyl)orthophosphinate ([N₁₈₈₈][P₅₀₇])

Li

O/A ratio of 10:1

⁵⁰

1-decyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide ionic liquid

Li, Co, Ni

low pH (pH < 3)

⁵¹

trihexyltetradecylphosphonium ([PC₆C₆C₆C₁₄], paired with (choloride ([Cl⁻]), dicyanamide ([-N(CN)₂⁻]), and bis(trifluoromethyl sulfonyl)amide ([-NTf₂⁻])

As, Cr, Cd, Cu, Zn, Pb, and Hg

pH of 7, quantity of IL (20 mg), contact time (15 min) and stirring speed (100 rpm)

⁵²

[C₈H₁₇NH₂][Cyanex 272]

Co²⁺

pH_eq of 4.5, t_e of 40 min, C_TSILs of 0.29 mol/L, (O/A) of 1:1, and T_e of 298 K

⁵³

trihexyl(tetradecyl)phosphonium thiocyanate or nitrate ([C101][SCN], [C101][NO₃])

Nd(III) and Dy(III)

t_e of 60 min, T of 25 ⁰C, pH of 2, Shaking speed: 2000 rpm, concentration of CaCl₂ in the aqueous phase of 2.5 M, 65.7 g/L Nd(III) and 13.5 g/L Dy(III), Retention time of 15 min, and O:A ratio of 1:1

⁵⁴

carboxymethyl trimethylammonium bis(trifluoromethyl)sulfonimide

Li

pH of 3, A/O of 1:2, 298.15 K, standard atmospheric pressure

¹³

Trihexyl (tetradecyl)phosphonium chloride [P₆₆₆₁₄⁺][Cl⁻] and trihexyl(tetradecyl)phosphonium bis(2,4,4- trimethylpentyl)phosphinate [P₆₆₆₁₄⁺][BTMPP⁻]

Ti

room temperature (25 °C), t_e of 10 min, stirring rate of 450 rpm