Within the past two decades, calixarenes have been examined for their properties in effecting the separation of radionuclides for a variety of purposes.  The goals of many of these studies have been to separate elements possessing similar chemistry and oxidation states but slightly different radii, such as the lanthanides, americium, and curium.   Carbamoylmethylphosphine oxide (CMPO), a ligand that has been shown to be selective for separating trivalent f-block elements, was attached to the upper rim of the calixarene in some of these studies in order to achieve such separations. In the overwhelming majority of these studies, these modified calixarenes have been used in liquid-liquid extraction systems.  Recently, we have succeeded in anchoring a CMPO-modified calix[4]arene to porous silica.  The synthesis of this new material has allowed us to investigate the radionuclide sorption properties of the anchored CMPO-modified calix[4]arenes, within the context of  a solid-supported system, rather than a liquid-extraction system. Preliminary studies have been undertaken to investigate the sorption of europium on the silica-anchored CMPO-modified calix[4]arene system.  These initial studies show the effect of ionic strength and pH on the calix[4]arene's ability to effectively sorb europium, and extend to a study of other lanthanides, as well as americium and curium.

Silica-anchored CMPO-modified calix[4]arenes for radionuclide separations

248th National Meeting (2014)

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