A new technique for selective separation and enrichment of platinum group metals (platinum, palladium, rhodium, iridium, ruthenium) from model hydrochloric and chloride media into hydrophobic deep eutectic solvents without the use of chelating agents is presented for the first time. The process consists in extraction of precious metals into an eutectic solvent based on tetraoctylammonium bromide and a carboxylic acid with further re-extraction of metals with ammonium hydroxide and nitric acid solutions. The extraction efficiency of metals from 0.1 M HCl was > 99.7 % for Pt and Pd; 87.3 % for Ru; 45.1 % for Ir; 28.5 % for Rh using the tetraoctylammonium bromide/hexanoic acid eutectic solvent. The developed technique was applied for the separation of platinum and palladium from refinery wastewater to obtain individual fractions with purity of > 99.9 %. The procedure does not involve the use of toxic, volatile or flammable solvents and can be an environmentally benign alternative to traditionally used approaches.

Original languageEnglish
Article number122427
JournalSeparation and Purification Technology
StatePublished - 15 Jan 2023

    Research areas

  • Deep eutectic solvents, Noble metals, Precious metals, Refinery, Solvent extraction

    Scopus subject areas

  • Analytical Chemistry
  • Filtration and Separation

ID: 100768611