Studies on the Use of Ionic Liquids as Potential Extractants of Phenolic Compounds and Metal Ions

Abstract The present work was aimed at investigating the usefulness of 1‐(n‐alkyl)‐3‐methylimidazolium‐derived ionic liquids (ILs) 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 IL. 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 then were performed with some selected ILs. The effects of temperature and the pH on the distribution ratio of solutes between the IL/aqueous phases also were analyzed. The results suggest that some of the ionic liquids tested are adequate to extract metal ions and organic compounds from aqueous solutions, with a high efficiency in some instances.

[1]  K. R. Seddon.  Ionic Liquids for Clean Technology , 1997 .

[2]  H. Helgeson,et al.  Thermodynamics of hydrothermal systems at elevated temperatures and pressures , 1969 .

[3]  R. P. Swatloski,et al.  Task-specific ionic liquids for the extraction of metal ions from aqueous solutions , 2001 .

[4]  Robin D. Rogers,et al.  Room temperature ionic liquids as novel media for ‘clean’ liquid–liquid extraction , 1998 .

[5]  Robin D. Rogers,et al.  LIQUID/LIQUID EXTRACTION OF METAL IONS IN ROOM TEMPERATURE IONIC LIQUIDS , 2001 .

[6]  C. Selomulya,et al.  Mechanisms of Cr(VI) removal from water by various types of activated carbons , 1999 .

[7]  G. Choppin,et al.  Principles and practices of solvent extraction , 1992 .

[8]  C. Barnes,et al.  Solvent extraction of strontium nitrate by a crown ether using room-temperature ionic liquids† , 1999 .

[9]  G J Lye,et al.  Room-temperature ionic liquids as replacements for organic solvents in multiphase bioprocess operations. , 2000, Biotechnology and bioengineering.

[10]  Mohammed M. Farid,et al.  Adsorption kinetics for the removal of chromium(VI) from aqueous solution by adsorbents derived from used tyres and sawdust , 2001 .

[11]  Robin D. Rogers,et al.  Characterization and comparison of hydrophilic and hydrophobic room temperature ionic liquids incorporating the imidazolium cation , 2001 .

[12]  Y. Marcus.  Principles of Solubility and Solutions , 1993 .

[13]  Robin D. Rogers,et al.  Traditional Extractants in Nontraditional Solvents: Groups 1 and 2 Extraction by Crown Ethers in Room-Temperature Ionic Liquids† , 2000 .

[14]  S. Datta,et al.  Studies on transport mechanism of Cr(VI) extraction from an acidic solution using liquid surfactant membranes , 2001 .

[15]  Zusing Yang,et al.  Room temperature ionic liquid as a novel medium for liquid/liquid extraction of metal ions , 2003 .