Crown Ethers as Solvent Extraction Reagents: Where do We Stand?

Cesium and Strontium Separation Technologies Literature Review

“…Various crown ethers have been found to be effective for extracting either cesium or strontium from aqueous streams. Early pioneering investigations of crown ethers as extractants for cesium and strontium were performed by Davis at the University of South Carolina and by McDowell at Oak Ridge National Laboratory [58][59][60][61].…”

Ion Recognition Approach to Volume Reduction of Alkaline Tank Waste by Separation and Recycle of Sodium Hydroxide and Sodium Nitrate

“…Surprisingly, a single study involving phenols represents the only citation of such a process in the literature. 22,23 As before, a cation receptor may be added to the solvent as a synergist 24 for the cation exchanger (Case 7), and one may envision that the cation receptor could also contain the cation-exchange functionality in the same molecule (Case 8). Whereas the desired extraction-stripping cycle is again possible using water for stripping, the major advantage of any of the cation-exchange approaches is the potentially high selectivity for OH -ion.…”

Design and Synthesis of the Next Generation of Crown Ethers for Waste Separations: An Inter-Laboratory Comprehensive Proposal

“…One of the major generic problems i n the application of selective crown ethers and calixarenes has been the fact that these neutral extractants require co-transfer of an anion; that is, an ion pair is transferred from the aqueous to the organic phase [17][18][19]. Although the crown compounds accommodate the cation, the anion remains largely solvated by the organic diluent or polymer matrix.…”