Crown Ethers as Carriers for the Transport of Anionic Thiocyanate Complex of Uranyl Ion Across a Bulk Liquid Membrane

Transport of UO2+ 2 as its anionic thiocyanate complex [UO2(SCN)4]2− across a bulk liquid membrane using 18 Crown 6 (18C6) and Dibenzo 18 Crown 6 (DB18C6) as carriers in the membrane phase has been studied. The anionic complex is formed by the addition of KSCN to the feed solution at a pH of 1. A dilute acid (pH = 5) served as the stripping agent in the receiving compartment. The interference from Th(IV) and a few other cations could be eliminated by using EDTA as a masking agent in the feed solution. Various factors influencing the transport process have been studied and an uphill transport (>89%) of UO2+ 2 from the feed solution could be accomplished under optimum conditions.