New menthol-based eutectic solvents and their extraction properties towards metal ions

Deep eutectic solvents are increasingly being used as extraction media as their properties are easily tunable and they can fulfill the green chemistry criteria. In this study, a range of hydrophobic (deep) eutectic solvents was developed as potential extractants of elemental impurities. The experimental results provided insights into the solid-liquid equilibrium of the binary mixtures containing menthol with various organic compounds. The NMR and FTIR spectroscopy were applied to characterize the eutectic compositions. The extraction property towards elemental species was evaluated in the terms of distribution coefficient for 24 elements. It has been shown that the inclusion of a chelating reagent as сompnent of the eutectic solvent can significantly increase the group extraction efficiency of metal ions.