Effect of Alkyl Group Structure on the Separation of Am(Ⅲ) From Lathanides(Ⅲ)

The effect of alkyl group structure of dialkyldithiophosphinic acid on separating Am(Ⅲ) from Eu(Ⅲ) is investigated. With four kinds of dialkyldithiophosphinic acids(HA) with different alkyl group of C 8(alkyl= n octyl, 1 methylheptyl,2 ethylhexyl,2,4,4 trimethylpentyl) as extractants and kerosene as diluent, the dependencies of extracting Am(Ⅲ) and Eu(Ⅲ) on pH and extractant concentration are determined. The slopes of lg D ～pH dependencies are close to 3 and the slopes of (lg D -3pH)～lg c ((HA) 2) are close to 2 except for di n octyldithiophosphinic acid extracting Eu(Ⅲ). While the organic phases are 0.2 mol/L extractants in kerosene and aqueous phase is 1 mol/L NaNO 3, the pH 1/2 values of aqueous phase for extracting tracer amount of 241 Am by HA with R= n octyl, 1 methylheptyl, 2 ethylhexyl, 2,4,4 trimethylpentyl are 2 31, 2 56, 2,58, 3 14, respectively, and the pH 1/2 values of aqueous phase for extracting tracer amount of 152,154 Eu(Ⅲ) by HA with R=1 methylheptyl, 2 ethylhexyl, 2,4,4 trimethylpentyl are 3 95,4 01, 4 42, respectively. The alkyl group has some effect on the extraction power to Am(Ⅲ) and Eu(Ⅲ), but has no substantial effect on SF Am/Eu.