Homogeneous Liquid-Liquid Extraction of Metal Ion Utilizing Upper Critical Solution Temperature of Propylene Carbonate

This study was undertaken to investigate the extraction of In3+ and Ga3+ by 7-(4-ethyl-1-methyloctyl)-8-hydroxy-quinoline (Kelex100), which has been found to be a slow extraction process. Homogeneous liquid-liquid extraction utilizing upper critical solution temperature of 4-methyl-1,3-dioxolan-2-one (propylene carbonate, abbreviated as PC) was used to eliminate the interface and speed up the extraction, since distribution between two phases was thought to be the rate-determining step. The effect of contact time on the percentage of metal extraction was examined at 80ºC using Kelex100 dissolved in toluene and PC solutions and the difference between two solvents was evaluated. The results clearly show that the use of homogeneous liquid-liquid extraction using PC with Kelex100 is faster than traditional two phase extraction