화학공학소재연구정보센터
Journal of Hazardous Materials, Vol.347, 478-485, 2018
Liquid-liquid extraction and facilitated transport of f-elements using an N-pivot tripodal ligand
Diglycolamide (DGA)-functionalized tripodal ligands offer the required nine-coordinated complex for effective binding to a trivalent lanthanide/actinide ion. A N-pivot tripodal ligand (TREN-DGA) containing three DGA pendant arms was evaluated for the extraction and supported liquid membrane transport studies using PTFE flat sheets. Solvent extraction studies indicated preferential extraction of 1:1 (M:L) species, while the metal ion extraction increased with increasing HNO3 concentration conforming to a solvated species extraction. Flat sheet-supported liquid membrane studies, carried out using 4.0 x 10(-3) M TREN-DGA in 95% n-dodecane + 5% iso-decanol indicated faster mass transport for Eu3+ ion as compared to Am3+ ion. The determined transport parameters indicated slow diffusion of the M-TREN-DGA (M = Am or Eu) complex being the rate-determining step. The transport of lanthanides and actinides followed the trend: Eu3+ >Am3+similar to Pu4+ >> UO22+ and Am can be selectively separated from a mixture of U and Pu by oxidizing the latter to its +6 oxidation state. The liquid membrane stability was not encouraging and was deteriorating the transport efficiency with time, which was attributed to carrier loss into the aqueous phases. (C) 2018 Elsevier B.V. All rights reserved.