Liquid-liquid extraction and selective sorption of actinides by use of carbamoyl-phosphonic ligands

A series of carbamoyl-phosphonates and carbamoyl-methylenephosphonates has been used for the liquid-liquid and selective sorption of a series of actinides. Liquid-liquid extraction into xylene layers has been investigated as a function of various experimental conditions and under the effect of different parameters. The extraction mechanism involves the formation of a 1:3 metal to ligand adduct, and the anion of the acid present in the aqueous samples plays a role in the phase transfer. The loading of a solid sorbent (XAD-4) with the ligand has been used for the selective sorption of actinides. The mechanism is similar to that operating in the liquid-liquid extraction. The uptake of the metals from the solution by the loaded resin may be used for recovery and preconcentration. (orig.)