Thioglycolate-based task-specific ionic liquids: Metal extraction abilities vs acute algal toxicity

Sonja Platzer, Raphlin Leyma, Sara Wolske, Wolfgang Kandioller, Esther Heid, Christian Schroeder, Michael Schagerl, Regina Krachler, Franz Jirsa (Corresponding author), Bernhard K. Keppler

Publications: Contribution to journalArticlePeer Reviewed

Abstract

We studied the extraction behavior of two thioglycolate-based ionic liquids (ILs), for heavy metals from aqueous solutions; substances of interest were methyltrioctylammonium S-hexyl thioglycolate [N 1888][C 6SAc] and methyltrioctylphosphonium S-hexyl thioglycolate [P 1888][C 6SAc]. Theses ILs previously have shown very good extraction abilities towards cadmium and copper, therefore we investigated time-dependent metal removal experiments with aqueous solutions of cobalt(II), nickel(II) and zinc(II). The highest distribution ratio (R IL/Water) was determined for zinc (R IL/Water = 2000). Recovery studies for zinc after extraction were performed with different stripping agents showing a successful recycling. Additionally, the two ILs were immobilized on active charcoal, displaying great potential for solid-liquid extraction. Regarding the extraction mechanism, quantum-mechanical calculations were included, which indicate that the metal extraction depends on the stability of the metal-water cluster. Ligands (water as well as ILs) are planar coordinated in nickel complexes but showed a tetrahedral configuration for zinc. As a first estimate of the ecotoxicity of the ILs, in vivo tests toward three freshwater green algae species Tetradesmus obliquus, Desmodesmus armatus and Raphidocelis subcapitata were carried out. The EC 50 values (effective concentration after 72 h) confirm high toxicity of all tested ILs to all species, displaying only small differences between the species and EC 50ies.

Original languageEnglish
Pages (from-to)113-119
Number of pages7
JournalJournal of Hazardous Materials
Volume340
DOIs
Publication statusPublished - 15 Oct 2017

Austrian Fields of Science 2012

  • 104003 Inorganic chemistry
  • 104023 Environmental chemistry

Keywords

  • Ionic liquids
  • Metal extraction
  • DFT calculation
  • Algal toxicity
  • Immobilization
  • PSEUDOKIRCHNERIELLA-SUBCAPITATA
  • ACTIVATED CARBON
  • IMMOBILIZATION
  • IMIDAZOLIUM

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