Actinide Speciation and Coordination Chemistry in Room Temperature Ionic Liquids and Supercritical Fluids
University of Idaho Seed Grant
Reprocessing of spent nuclear fuel with recycling of fissile isotopes is necessary to optimize energy extraction from actinide resources and to minimize waste product production. Conventional separation processing of actinides and fission products requires the use of hazardous organic solvents with relatively high disposal costs. However, novel separations processes using room temperature ionic liquids (RTIL's) either alone or in combination with supercritical fluid CO2 (sc-CO2) are being developed. The RTIL can be reused and the sc-CO2 phase recycled, after removal of radionuclides. The overall goal of the project described here is to clarify the fundamental molecular level interactions that underlie extractions of actinides and lanthanides into RTIL'S and sc-CO2. Understanding these chemical interactions will help researchers to better understand the extraction mechanisms at play in the RTIL/sc-CO2 system, and to more fully optimize extraction efficiencies as well as to develop new extraction techniques. I propose to use Raman and infrared spectroscopies to study how molecular interactions between RTIL's and sc-CO2 affect actinide speciation and solvation in mixtures of those solvents under differing conditions of pressure, temperature, and complexing ligand.