Effect of Complexing Agent on Transport of Lanthanoid Elements across Versatic Acid Liquid Membrane

Abstract
Transport of several trivalent lanthanoids (La, Nd, Sm, Eu, Tb, Tm, and Lu) was examined across a supported liquid membrane (SLM) containing Versatic 10 (VA10) in kerosene. Lanthanoids in the feed solution can be effectively transported and concentrated into the product solution. Separation factors obtained from the transport rates for lighter lanthanoids were larger than those for heavier lanthanoids, in agreement with the result on the distribution ratios in liquid-liquid extraction. The separation factors for heavier lanthanoids were enhanced by the addition of citrate to the feed solution. The transport rate was controlled by the extraction process from the feed solution to the SLM and the diffusion process of lanthanoid-VA10 complexes in SLM.