Phosphonium ionic liquids as extractants for recovery of ruthenium(III) from acidic aqueous solutions

Abstract

The aim of this work is to investigate extraction of ruthenium(III) from acidic aqueous solutions with phosphonium ionic liquids such as trihexyl(tetradecyl)phosphonium chloride (Cyphos IL 101), trihexyl(tetradecyl)phosphonium bis(2,4,4-trimethylpentyl)phosphinate (Cyphos IL 104) and tributyl(tetradecyl)phosphonium chloride (Cyphos IL 167) as extractants. The influence of HCl content in the feed solutions on extraction of Ru(III) was investigated. The research was performed for model solutions containing Ru(III) and a mixture of waste solutions containing Ru(III) and Rh(III). In addition, investigation of the type of extractant and its concentration in the organic phase on extraction of Ru(III) was carried out. Co-extraction of protons to the organic phase was determined. To the best of our knowledge, the extraction of Ru(III) with Cyphos IL 167 (tributyl(tetradecyl)phosphonium chloride) as an extractant has not yet been described in the scientific literature.

Keywords: Cyphos IL 101; Cyphos IL 104; Cyphos IL 167; Liquid–liquid extraction; Phosphonium ionic liquid; Rhodium(III); Ruthenium(III).

Fig. 1

Effect of shaking time on the extraction of a Ru(III) and b Rh(III) from the mixture of these metal ions (Organic phase: 5 × 10⁻³ M (filled square) IL 101; (filled circle) IL 104; (filled triangle) IL 167 in toluene)

Fig. 2

Effect of ILs concentration in the organic phase on extraction of a Ru(III) and b Rh(III) from the mixture of these metal ions (Organic phase: (filled square) IL 101; (filled circle) IL 104; (filled triangle) IL 167 in toluene)