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

Author(s)

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

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.

Organisation(s)

Department of Inorganic Chemistry, Department of Computational Biological Chemistry, Functional and Evolutionary Ecology

External organisation(s)

Technische Universität Wien, University of Johannesburg (UJ)

Journal

Journal of Hazardous Materials

Volume

340

Pages

113-119

No. of pages

7

ISSN

0304-3894

DOI

https://doi.org/10.1016/j.jhazmat.2017.06.053

Publication date

10-2017

Peer reviewed

Yes

Austrian Fields of Science 2012

104003 Inorganic chemistry, 104023 Environmental chemistry

Keywords

ASJC Scopus subject areas

Pollution, Waste Management and Disposal, Health, Toxicology and Mutagenesis, Environmental Engineering, Environmental Chemistry

Portal url

https://ucrisportal.univie.ac.at/en/publications/thioglycolatebased-taskspecific-ionic-liquids-metal-extraction-abilities-vs-acute-algal-toxicity(088e7488-d3bb-4b98-9b3e-791df2c69374).html