Extraction behaviors of platinum group metals from an aqueous HNO3 solution using ionic liquids containing a novel thiodiglycolamide-type extractant

A novel N , N '-dimethyl- N , N '-di-(2-phenylethyl)-thiodiglycolamide (MPE-TDGA) extractant that was soluble in imidazolium-based ionic liquids (ILs), such as 1-butyl-3-methyl-imidazolium nonafluorobutansulfonate ([Bmim][NfO]), was synthesized for the efficient and selective extraction of platinum group metals (PGMs) from simulated high-level liquid waste (HLLW) using ILs. The ILs containing MPE-TDGA enabled the rapid extraction of Pd(II). The extraction of Rh(III) was accelerated by increasing temperature. In contrast conventional organic solvent systems and the 1-Butyl-3-methylimidazolium bis(trifluoromethanesulfonyl)imide system, slope analysis suggested that Pd(II) forms considered to form a 1:1 complex with MPE-TDGA in [Bmim][NfO]. The [Bmim][NfO]-containing MPE-TDGA demonstrated the effective extraction of PGMs from simulated HLLW at 50 °C.