Octaphosphinoylated para-tert-butylcalix[8]arene as an extracting agent for uranyl ions in an acidic nitrate medium: study of the extracted uranyl calixarene compound

The uranyl ion extraction properties of an octaphosphinoylated para-tert-butylcalix arene (B₈bL⁸) in CHCl₃ from an aqueous-acidic-saline medium containing a uranyl nitrate salt were investigated. UV-Vis and luminescence techniques allowed us to evaluate the extraction capability and loading capacity of B₈bL⁸ towards uranyl ions. Both techniques revealed a 2 UO₂²⁺:1 B₈bL⁸ stoichiometry for the main extracted species in the organic phases. IR, NAA, and XPS analyses of the pure solid recovered from the extracts demonstrated such a stoichiometry. B₈bL⁸ in CHCl₃ would be highly useful for the treatment of nuclear or radioactive wastes containing uranium in rich aqueous-acidic-saline media. (author)