Calixarene derivatives for An(III)/Ln(III) separation in nuclear fuel reprocessing

In the process of partitioning HLW, an urgent subject is focus on the development of extraction ligands for actinides (An(III)) over lanthanides (Ln(III)) with excellent selectivity. It is well known that the preorganization of ligands considerably improves their extraction capacity and selectivity to certain cations. Calixarenes offer ideal platforms to such preorganization. From the 1990s on, large amounts of calixarene derivatives bearing various complexation functionalites to An (III) have been synthesized. Many of them showed improved extraction properties and higher extraction selectivity to An(III). In this review, the An(III)/Ln(III) extraction properties of various calixarene derivatives bearing ligands, such as carbamoylmentylphosphine oxide, dialkylphosphine oxide, picolinamide, and other function moities, were summarized at large. Emphasis was placed on the relationship of the structures of the calixarene derivatives to the preorganization of ligands, the extraction properties and the separation factor of An(III)/Ln(III). The developing directions and the potential application of such derivatives for An(III)/Ln(III) separation were described.