Studies on the use of ionic liquids as potential extractants of phenolic compounds and metal ions

Vidal, S.T.M.; Correia, M.J.N.; Marques, M.M.; Ismael, M.R.; Reis, M.T.A.

Key information

Authors:

Vidal, S.T.M.; Correia, M.J.N. (Maria Joana Castelo-Branco de Assis Teixeira Neiva Correia); Marques, M.M. (Maria Matilde Soares Duarte Marques); Ismael, M.R. (Maria Rosinda Da Costa Ismael); Reis, M.T.A. (Maria Tereza Angelino Reis)

Published in

August 19, 2004

Abstract

The present work was aimed at investigating the usefulness of 1-(n-alkyl)-3-methylimidazolium-derived ionic liquids in liquid-liquid separation processes. For this purpose, a series of 1-(n-alkyl)-3-methylimidazolium tetrafluoroborates and hexafluorophosphates were prepared by standard synthetic methods and characterized by 1H NMR. Experiments were performed to assess the influence of the alkyl group and the anion on the physical properties of the ionic liquid. Equilibrium studies on the extraction of heavy metal ions (copper, zinc and chromium) and some common pollutant aromatic compounds (phenol, tyrosol and p-hydroxybenzoic acid) from aqueous media were then performed with some selected ionic liquids. The effects of temperature and pH on the distribution ratio of solutes between the ionic liquid/aqueous phases were also analyzed. The results suggest that some of the ionic liquids tested are adequate to extract metals ions and organic compounds from aqueous solutions with a high efficiency in some instances.