Kinetic and Thermodynamic Requirements to Extend Solvent Compatibility in Thermal-Assisted Extraction of Inert Platinum Group Metals

Zhiwei Zheng, Tsuyoshi Arai, Koichiro Takao

Research output: Contribution to journalArticle


The extraction behavior of inert platinum group metals (PGMs) like Ru(III) and Rh(III) has been investigated in a HNO3(aq)/1-octanol system with a pyridinediamide. As a result, low efficiency of Ru(III) extraction arose from its slow kinetics at 298 K, while the situation was not improved very much even at 356 K. Addition of a hydrophobic anion like Tf2N- increased Ru(III) extraction up to 95% within 3 h at 356 K, where a synergistic effect would be present. Extraction of a more inert PGM like Rh(III) was also enhanced up to 90% within 2 h at 356 K in the presence of Tf2N-. We have successfully demonstrated the rapid and efficient extraction of inert PGMs from HNO3(aq) to 1-octanol, which is one of the ordinary organic solvents.

Original languageEnglish
Pages (from-to)9750-9753
Number of pages4
JournalACS Sustainable Chemistry and Engineering
Issue number11
Publication statusPublished - 2019 Jun 3



  • Hydrophobic anion
  • Ordinary organic solvent
  • Platinum group metals
  • Solvent extraction
  • Thermal-assistance

ASJC Scopus subject areas

  • Chemistry(all)
  • Environmental Chemistry
  • Chemical Engineering(all)
  • Renewable Energy, Sustainability and the Environment

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