Transport of uranyl ion across a bulk liquid membrane using calixarene andsynergistic agents as carriers

Transport of uranyl ion across a bulk liquid membrane using chloroform solu tions of calixarenes (as carriers) has been studied. Various factors that a ffect the transport have been optimised in order to obtain maximum transpor t. It has been observed that the use of tri-n-octyl phosphine oxide (TOPO) as a synergistic reagent showed a marked enhancement of transport of uranyl ion. Crown ether 18 Crown 6 (18C6) also exhibited synergistic behaviour wh en used in combination with calixarenes. The use of these synergistic reage nts resulted in high transport of uranyl ion with 0.1 M nitric acid as the receiving solution. The interference from different transition metal ions w as found to be negligible. The serious interference from Th(IV) could be mi nimised by using EDTA as masking agent. A possible application of this carr ier system and transport process to the pre concentration and recovery of u ranium from seawater has also been examined. (C) 2002 Elsevier Science B.V. All rights reserved.