Room-temperature ionic liquids (RTILs) have recently received increasing attention as solvent alternatives for possible application in spent fuel reprocessing, particularly in the extraction of metal ions from high-level radioactive aqueous waste, due to their unique physical and chemical properties. Herein, the solvent extraction of the uranyl ions (UO2 2+) was performed using N,N- diethyl-N,N N-di(para)tolyl-dipicolinamide (Et(p)TDPA) as the extractant in a commonly used ionic liquid 1-butyl-3- methylimidazolium hexafluorophosphate ([C4mim][PF6]). The effects of vortexing time, phase ratio and the concentration dependence of Et(p)TDPA, nitric acid and sodium nitrate on the extraction were studied in detail. The extraction mechanismwas deduced based on the slope analysis and UV-vis measurement. The distribution ratio of U from 3mol/Lnitricacidby0.3mol/LEtTDPA/C4mimPF6 is found to be almost 100. Conventional log-log plot analysis of the extraction equilibrium data suggests that the ions are extracted as a complex in 2 : 3 ratio of UO2 2+ to extractant, and the extractionmost likely occurs by a cationexchange mode since the concentration of C4mim+ in the aqueous phase increases linearly with the percent extraction of UO2 2+ evidenced by UV-vis measurement. This work promises to provide new efficient media based on RTILs for separation of uraniumfromthe radioactive aqueous waste.
- Ionic liquid
- Solvent extraction
ASJC Scopus subject areas
- Physical and Theoretical Chemistry