Complexation of Americium(III) with Crown Ethers in Aqueous Phase

Abstract

The complexation behaviour of Am(III) with 12-crown-4, 15-crown-5, 18-crown-6 and dicyclohexyl-18-crown-6 in aqueous phase has been investigated using the solvent extraction tracer technique, keeping [ligand] to [metal] ratio as high as 10 6 . As a consequence, very low complex formation constants (log/?! = 0.21 ±0.01) were measured. In our experimental conditions, 12-crown-4 forms 1:3 complex species, 15-crown-5 and 18-crown-6 form 1:2 species and dicyclohexyl-18-crown-6 forms 1:1 species with Am(III). The overall extraction equilibria were found to be enthalpy stabilized and entropy destabilized.

A novel approach for preferential recovery of Sr from (Sr, Th)O2

“…However, the transfer of cationic crown ether complex species across the inter phase necessitates the presence of suitable counter anion in the organic phase. The water content in the organic diluent plays key role for the strontium extraction from nitric acid media [17,18]. The oxygenated solvents like alcohols (capable of dissolving water as a consequence of hydrogen bonding) have been employed successfully for the transfer of hydrated nitrate (as counter anion) towards the organic phase.…”

Americium

“…Rogozina et al, 1974);[9] (Keller and Schreck, 1969); [10](Eberle and Moattar, 1972);[11] (Moattar, 1971); [12](Hubert et al, 1974(Hubert et al, , 1975; [13](Ohyoshi and Ohyoshi, 1971); [14](Moskvin et al, 1962);[15] (Marcu and Samochocka, 1966); [16](Bouhlassa and Guillaumont, 1984); [17](Wall et al, 2002);[18](Mohapatra and Manchanda, 1991); [19] ; [20](Baybarz, 1966); [21](Elesin and Zaitsev, 1971a);[22] (Shilov …”