Extraction of Americium with Substituted Calix[4]Arenes from Alkaline Solutions

Extraction of ²⁴¹Am and ¹⁵²Eu from carbonate-alkaline medias with solutions of functionalized calix4]arenes and their nonmacrocyclic analogs in m-nitrobenzotrifluoride was studied. The dependencies of the Am distribution ratios on pH of the aqueous phase in the range 10 -13.5 and on the position and nature of functional groups in the calixarene core were examined. The composition of extractable solvates of americium with functionalized calix4]arenes was determined. Thiacalixarenes extract americium more efficiently from alkaline solutions, as compared to calixarenes, demonstrating higher Am/Eu separation factor. Functionalization of the calixarenes improves the Am extraction efficiency and Am/Eu separation factor as well. In the case of thiacalixarenes, functionalization considerably decreases the extraction efficiency and selectivity.