Doubly crowned calix[4]arenes in the 1,3-alternate conformation as cesium-selective carriers in supported liquid membranes

Article abstract of DOI:10.1021/ac00114a006

Calix[4]biscrowns 9-15 in the 1,3-alternate conformation are prepared by a one-step procedure in ～50-80% yields, which are sufficiently high enough to allow their use as selective cesium carriers in supported liquid membranes (SLMs). The application of the Danesi diffusional model allows the transport isotherms of trace level 137Cs through SLMs (containing calix[4]biscrowns) to be determined as a function of the ionic concentration of the aqueous feed solutions. Compound 13 appeared to be much more efficient than mixtures of crown ethers and acidic exchangers, especially in very acidic media. Decontamination factors greater than 20 are obtained in the treatment of synthetic acidic radioactive wastes. Permeability coefficient measurements are conducted for repetitive transport experiments in order to qualify the SMLs' stability with time. Very good results (over 50 days of stability) and high decontamination yields are observed with 1,3-calix[4]biscrowns 13 and 14. The l,3-calix[4]biscrowns are shown to be a new family of selective carriers for cesium removal from radioactive liquid wastes.