CMPO-substituted calix[6]- and calix[8]arene extractants for the separation of An3+/Ln3+ from radioactive waste

Supramolecular ligands for the extraction of lanthanide and actinide ions

A selection of supramolecular ligands designed to extract f-elements.

Host-Guest Extraction of Heavy Metal Ions with p-t-Butylcalix[8]arene from Ammonia or Amine Solutions

The capacities of the p-t-butylcalix[8]arene (abbreviated as H8L) host to extract toxic divalent heavy metal ions and silver from aqueous solution phases containing ammonia or ethylene diamine to an organic phase (nitrobenzene, dichloromethane, or chloroform) were carried out. When the metal ions were extracted from an aqueous ammonia solution, the metal ion selectivity for extraction was found to decrease in the order Cd2+> Ni2+> Cu2+> Ag+> Co2+> Zn2+. When the aqueous phase contained ethylene diamine, excellent extraction efficiencies of 97% and 90% were observed for the heavy metal ions Cu2+ and Cd2+, respectively. Under the same conditions the extraction of octahedral type metal ions, namely, Co2+ and Ni2+, was suppressed. The extraction of transition metal cations by H8L in ammonia and/or amine was found to be pH dependent. Detailed analysis of extraction behavior was investigated by slope analysis, the continuous variation method, and by loading tests.

Ligands for f-element extraction used in the nuclear fuel cycle

This review describes the latest advances regarding the development, modification and application of suitable ligands for the liquid–liquid extraction of actinides and lanthanides from nuclear waste.

Pillar[5]arene-based diglycolamides for highly efficient separation of americium(iii) and europium(iii)

Pillar[5]arenes were functionalized with ten diglycolamide (DGA) arms on both sides of the pillar framework and were found to exhibit excellent separation and extraction efficiency towards Am(iii) and Eu(iii) at high acidity.

CMPO-calix[4]arenes and the influence of structural modifications on the Eu(III), Am(III), Cm(III) separation

The syntheses of new calix[4]arenes featuring CMPO groups on the wide rim are reported and the extraction of Am(III) and Eu(III) from concentrated HNO3 aqueous phases are discussed with reference to the properties of the symmetric tetra-CMPO derivative 1 . All extraction studies were conducted in the same experimental conditions which allows to directly compare the dependence of the distribution coefficients of various calixarenes on the acid concentration (0.1 M < [HNO3] < 5 M). Calix[4]arene 1 becomes a very poor extractant if the length of the aliphatic chain between the amide and phosphine oxide groups of CMPO is increased, if the bridging methylene groups are replaced by sulfur atoms or if the macrocyclic cavity size is increased. By contrast, mixed amide — CMPO calix[4]arenes are nearly as effective than 1 . Moreover, Am(III)/Cm(III) separation coefficients between 1.5 and 3 have been obtained with unsymmetrical calix[4]arenes of type 1 with different aliphatic chains grafted on the narrow rim. Guidelines to anticipate the extraction ability of calix[4]arenes remain elusive because of the intricate solution behavior of these compounds.

Upper-rim CMPO-substituted calix[6]- and calix[8]arene extractants for the An3+/Ln3+separation from radioactive waste

Two new ligands (1and2) for actinide/lanthanide separation derived from calix[6]- and calix[8]arenes functionalised at the upper rim with six or eight CMPO binding units were synthesised. These ligands, having a methoxy group at the lower rim, are conformationally mobile in solution at room temperature. Extraction data from water to a NPHE/n-octanol (90/10) solution of ligands1and2, in the presence of bromo-cosan as synergist, show that these derivatives are less efficient and selective than the previously reported homologues derived from calix[4]arenes or from the lower rim CMPO calix[6]- and calix[8]arenes, especially at high nitric acid concentrations. However, although compound1and2do not appear promising for the actinide/lanthanide separation from high acidity radioactive waste, the results obtained in this work disclose some important structural results which can be useful for the design of new efficient and selective polytopic ligands.