Surfactant gel adsorption of platinum(II), (IV) and palladium(II) as chloro-complexes and kinetic separation of palladium from platinum using EDTA

Anal Sci. 2007 Sep;23(9):1147-9. doi: 10.2116/analsci.23.1147.

Abstract

A micellar solution of cetylpyridinium chloride (CPC) can separate into two phases due to a temperature change or to the addition of salts. Platinum(II), (IV) and palladium(II) reacted with chloride ions to form stable anionic complexes of PtCl4(2-), PtCl6(2-) and PdCl4(2-), respectively, and were adsorbed onto the CPC gel phase. The CPC phase plays the role of an ion-exchange adsorbent for the anionic complexes. By such a procedure, the precious metals of platinum and palladium could be separated from base metals such as copper, zinc and iron. The kinetic separation was performed by a ligand exchange reaction of the palladium(II) chloro-complex with EDTA at 60 degrees C. The anionic palladium(II)-EDTA complex could not bind the opposite charged CP+ and was desorbed from the CPC phase. In the aqueous phase, the recovery of palladium(II) by the double-desorption was 101.1 +/- 1.2%. The platinum(II) and (IV) chloro-complexes were stable for at least 30 min and remained in the CPC phase.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adsorption
  • Cetylpyridinium / chemistry*
  • Edetic Acid / chemistry*
  • Gels
  • Hydrogen-Ion Concentration
  • Kinetics
  • Palladium / chemistry*
  • Palladium / isolation & purification*
  • Platinum / chemistry*
  • Surface-Active Agents / chemistry*
  • Temperature

Substances

  • Gels
  • Surface-Active Agents
  • Platinum
  • Palladium
  • Edetic Acid
  • Cetylpyridinium