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

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

Recycling of platinum group metals (PGM) is actively carried out from the viewpoint of stable supply of resources. There are few separating reagents that can separate PGM from each other, and development of a highly selective separating reagent is required. Ionic liquids (IL) are salts with the melting points below 100 degrees Celsius. An ionic liquid can be used as an alternative solvent instead of an organic solvent due to excellent chemical properties such as nonvolatility and nonflammability. In addition, IL can extract charged chemical species and can be functionalized by chemical modification. In this study, we synthesized a novel urea-substituted IL to achieve mutual separation of Pt(IV) and Pd(II). The novel IL synthesized in this study achieved mutual separation of Pt(IV) and Pd(II). Furthermore, spectroscopic analysis of the extraction mechanism revealed that Pt(IV) and Pd(II) were extracted by different extraction mechanisms.