Type V Deep Eutectic Solvents for Liquid Liquid Extraction A Versatile Platform for Metal Recovery Pharmaceutical Pollutant Removal and Fuel Purification

Abstract

Chapter 1 briefly describes different methods used in chemistry for separation or extraction of specific components from liquid phase. It includes adsorption, membrane filtration, precipitation, liquid-liquid extraction etc. It also describes ionic liquids (ILs) and deep eutectic solvents (DESs) as extractants. This chapter gives a clear idea about the different type of DES with an emphasis on type V DES, its importance, advantages and applications. The chapter discusses various methods and systems explored for extraction of REEs from scrap NdFeB magnets, tetracycline removal from water, diesel purification by desulfurization, denitrogenation and dearomatization. newlineChapter 2 describes the chemicals used, synthetic methods and characterization techniques employed for the entire study. The principle behind various techniques such as FTIR, 1H-NMR, DSC, TOC, UV-Vis and HPLC are discussed. newlineChapter 3 employ hydrophobic eutectic solvents (HDES) prepared by mixing an extractant trioctylphosphine oxide (TOPO) with hydrogen bond donors thymol (THY), menthol (MEN), or lauric acid (LAAC) in 1:1 ratio. The prepared HDES was used as an extractant and hydrophobic phase to recover Nd(III) and Dy(III) from magnet leachate, thus avoiding the usage of volatile organic solvents. All three HDES formulations effectively extracted Nd(III) and Dy(III) from 1 mol/L HNO3. Notably, the THY:TOPO (1:1) composition showcased the most remarkable performance in terms of both separation factor and extraction capacity. Stripping Nd(III) and Dy(III) from loaded HDES was achieved using 2 mol/L H2SO4. Through the construction of a McCabe-Thiele diagram and the execution of counter-current experiments, the complete recovery of both Nd(III) and Dy(III) was realized. The THY:TOPO (1:1) also exhibited remarkable extraction capability for all three rare earth elements present Nd(III), Dy(III), and Pr(III) within the original scrap NdFeB magnet leachate at the optimized conditions. This study emphasizes the inherent advantages of formulating eutectic solven