Rational design of novel carboxylic acid functionalized phosphonium based ionic liquids as high-performance extractants for rare earths

摘要: Abstract Developing the novel ionic liquids as potential substitutes for conventional organic solvents in extraction of rare-earth metals is highly desirable but challenges still remain. In this study, well-designed carboxylic acid functionalized phosphonium based liquids, (4-carboxyl)butyl-trioctyl-phosphonium chloride/nitrate, were synthesized and characterized. The as-prepared samples tested undiluted hydrophobic acidic extractant metal ions, affording maximal loading 3 mol/mol towards Nd(III) aqueous solution remarkable stripping performance. results also reveal their excellent extractability selectivity Sc(III) mixtures six well outstanding separation properties between first row transition-metal ions (i.e., La/Ni, Sm/Co). Moreover, mechanism indicates that extracted complex via a proton exchange liquid phase structurally similar to complexes obtained with neutral extractants. This work presents prototype fabrication cation-functionalized efficient provides future application recycling from spent magnets.