Urea-substituted ionic liquid for the extraction and separation of Pd(II) and Pt(IV)

Ueda, Yuki   ; Sugita, Tsuyoshi   ; Okamura, Hiroyuki   ; Naganawa, Hirochika  ; Shimojo, Kojiro   

The separation and recovery of PGM is carried out by a hydrometallurgy process mainly based on a solvent extraction method. In recent years, development of alternative solvents for such volatile organic solvents has been advanced. Ionic liquids (IL) has attracted substantial interest in many fields as a green alternative solvent due to their non-volatile, non-flammable, and thermally stable properties. Task-specific ionic liquids (TSIL) that functionalized by incorporating ligating group can give the extraction ability for metal ions. Many extraction systems using IL and TSIL aimed at separating PGM have been reported so far, however there is no extraction system that achieves individual separation of Pd and Pt by one type of TSIL. In this study, imidazolium bis(trifluoromethanesulfonyl) imide type TSIL incorporating a urea group was synthesized and its extraction ability for Pd and Pt was evaluated from a viewpoint the individual separation of Pd and Pt.