Extraction of Neodymium by Bis(Trifluromethylsufonyl)imide Room Temperature Ionic Liquids

Abstract

Nuclear fuel reprocessing methods currently involve the use of organic solvents, in liquid-liquid extractions such as the PUREX process, to extract uranium and plutonium from other undesired fission products. A proposed way of making these processes more environmentally friendly and safer is to use room temperature ionic liquids (RTIL) in place of the organic solvents. Organic solvents are volatile and flammable, whereas many ionic liquids are neither. This makes the ionic liquids safer to use and more environmentally friendly. The focus of our research is on understanding the behavior of the lanthanide neodymium (Nd) in ionic liquids and how Nd is extracted from aqueous phases. The Nd was dissolved in aqueous bistriflimic acid solution. After the ionic liquids containing the bis(trifluromethylsufonyl)imide anion and tributyl phosphate (TBP) extractant were pre-equilibrated, the RTIL solutions were mixed individually with aqueous Nd, and the aqueous and organic layers were then separated. The ionic liquid and aqueous layers were analyzed through spectroscopy to determine the partition coefficients. Slope analysis of the partition coefficient at different TBP concentrations was used to determine the stoichiometry of coordination of TBP to neodymium. Results will be compared to prior work by other researchers using holmium, and other literature data.