Akira Tsuyoshi

Separation of Americium from Europium Using Liquid Membrane Impregnated with Organodithiophosphinic Acid

The selective transport of Am across a supported liquid membrane (SLM) has been investigated by using bis (2,4,4-trimethylpentyl)dithiophosphinic acid (Cyanex 301) as a mobile carrier. This extractant containing soft donor atoms exhibits strong affinity for actinoids, giving a large separation factor between trivalent Am and Eu. Separation of Am from Eu was achieved by an SLM containing highly purified Cyanex 301. Americium was preferentially transported across the SLM and concentrated in the product solution, while most of Eu remained in the feed solution.

HIGH-SPEED COUNTERCURRENT CHROMATOGRAPHY USING A SMALL COILED COLUMN

Separation of selected lanthanoid elements was performed by high-speed countercurrent chromatography (CCC) equipped with a small coiled column of a 10 cm3 capacity. A hexane solution of 2-ethylhexylphosphonic acid mono-2-ethylhexyl ester (EHPA) was retained in the tubing column as the stationary phase. The stationary phase retention increased with increasing rotational speed and with decreasing flow rate of the aqueous mobile phase. Mixtures of lanthanoids (Gd, Tb and Dy) were chromatographically eluted in the increasing order of extractability by introducing the buffered mobile phase, and excellent separation of lanthanoids was achieved. Lanthanoids (Sm through Er) and yttrium were simultaneously enriched in the stationary phase from a large volume of a sample solution, and then separated from each other with reasonable resolution.

Separation of yttrium(III) from iron(III) through liquid membrane impregnated with di(2-ethylhexyl)phosphoric acid

The selective transport of yttrium(III) in the presence of iron(III) through a supported liquid membrane (SLM) has been investigated by using di(2-ethylhexyl)phosphoric acid (DEHPA) as a mobile carrier. Yttrium(III) with fast kinetics was preferentially transported from the feed solution of dilute acid into the product solution of 1M H2SO4, while most of iron(III) with slow kinetics remained in the feed solution. The effective separation of yttrium(III) from a large amount of iron(III) was accomplished by the selective transport of yttrium(III) through the SLM.

HIGH-SPEED COUNTERCURRENT CHROMATOGRAPHIC PURIFICATION OF MIDDLE LANTHANOIDS

Separation of selected lanthanoid elements was performed by high speed countercurrent chromatography (CCC) employing a support–free stationary phase of 2–ethylhexylphosphonic acid mono–2–ethylhexyl ester (EHPA) in toluene. Middle lanthanoids (Sm, Eu, Gd, Tb, Dy) were chromatographically eluted in their increasing order of extractability by passing the aqueous mobile phase of pH buffers. The mixtures of lanthanoid elements of different concentrations were isolated into individual elements of high purity by one–step chromatographic operation.