Hydrophobic deep eutectic solvents and its application in extraction and separation in aqueous media

Abstract

Deep eutectic solvents are a class of new green solvents. However, the deep eutectic solvents reported in literatures so far are mainly limited to hydrophilic deep eutectic solvents, which are not stable in water, and unable to be used in the systems involving water. To resolve this problem, hydrophobic deep eutectic solvents are particularly attractive in recent years. In this work, the concept of deep eutectic solvents is firstly discussed, and then the application of hydrophobic deep eutectic solvents in the extraction/separation of volatile fatty acids, lower alcohols, bisphenol A, pesticides, heavy metals and rare metals from aqueous solutions has been critically reviewed. The developing trend has been analyzed for the hydrophobic deep eutectic solvents based liquid-liquid extraction / separation, and the main issues are suggested for the future researches.