Journal of Chemical Engineering of Japan, Vol.50, No.7, 521-526, 2017
Extraction and Stripping Behavior of Platinum Group Metals Using an Amic-Acid-Type Extractant
The recovery and separation of platinum group metals (PGMs) are of considerable significance for metal sustainability. To establish an effcient extraction process for PGMs, the novel extractant N-[N,N-di(2-ethylhexyl)aminocarbonylmethyl] phenylalanine (D2EHAF), containing a phenylalanine moiety as the metal-affinity group, was synthesized. The extraction of PGMs from aqueous HCl and HNO3 solutions with D2EHAF, or our previously developed N-[ N, N-di(2-ethylhexyl) aminocarbonylmethyl]glycine (D2EHAG), in n-dodecane was investigated. Both D2EHAF and D2EHAG exhibited high extraction affinities for Os4+, Pt4+, and Pd2+ in aqueous HCl. In a HNO3 solution, D2EHAF extracted Pd2+ more efficiently than D2EHAG, and the extraction of Pd2+ from a 1 mol dm(-3) HNO3 solution with D2EHAF proceeded quantitatively. The extracted metal ions were stripped from the organic solution using a highly acidic solution, or thiourea.