Effect of Crown Ethers on the Ion-Exchange Behavior of Alkaline Earth Metals. Toward Improved Ion-Exchange Methods for the Separation and Preconcentration of Radium

摘要

The effect of selected crown ethers on the uptake of alkaline earth cations by sulfonic acid and diphosphonic acid-based cation-exchange resins from hydrochloric acid media is examined. The effect observed is shown to vary with the hydrophobicity of the crown ether. Water-soluble crown ethers enhance the sorption of certain cations, thereby improving the selectivity of the resin for other alkaline earths over calcium ion, an apparent result of a synergistic interaction between crown ether present in the resin phase and the ionic functional groups of the resin.