BEHSA grafted polymer for selective extraction of U(VI), Th(IV) and La(III) from acidic matrices and environmental samples – a green process

Liquid chromatographic behavior of lanthanides and actinides on monolith supports

Burn-up measurement for the fast reactor fuels in general and measurements on short cooled dissolver solutions in particular pose a great challenge due to the high level of radioactivity associated with the solution. An HPLC technique using monolith support has been developed for the first time for the determination of burn-up of fast reactor fuels and applied to the dissolver solution of the FBTR (Fast Breeder Test Reactor, Kalpakkam, India) fuel discharged at nominal burn-up of 150 GWd/t. A dynamic ion-exchange technique developed for the individual separation of lanthanides as well as actinides in connection with the burn-up measurements, has led to separation of all 14 lanthanides in about 2.77 min, the fastest LC technique as of now in literature and has resulted in a significant reduction in analysis time, radiation dose to operator and liquid waste generation. The dissolver solution was injected directly into the HPLC and assayed for lanthanide fission products, uranium, and plutonium using appropriate dilutions. The atom percent fission was calculated based on these measurements and the results are discussed. A reversed-phase chromatographic technique was also employed for the determination of uranium and plutonium in the dissolver solution. The sorption behaviour of uranium and thorium was examined on a monolith support modified with bis-2-ethylhexyl succinamic acid (BEHSA). Rapid separation of uranium from thorium could be achieved in about 20 s on the modified monolith support.

Retention studies on uranium, thorium and lanthanides with amide modified reverse phase support and its applications

The retention behaviour of uranium and thorium was investigated on modified reverse phase supports using 3-oxo-pentanedioicacid bis-[bis-(2-ethyl-hexyl)-amide (OPAEHA), 3-oxo-pentanedioicacid bis diisobutyl amide (OPAIBA) and bis-2-ethylhexyl succinamic acid (BEHSA). alpha-Hydroxy isobutyric acid (alpha-HIBA) was employed as the complexing reagent for elution. Elution profiles of uranium and thorium were studied as a function of the modifier concentration, mobile phase composition and its pH. Based on these investigations, a novel high performance liquid chromatography (HPLC) based separation technique was developed using BEHSA modified support for the isolation and quantitative determination of lanthanides as a group in uranium matrix. Hundreds of samples obtained from pyrochemical reprocessing of molten salts containing lanthanides in uranium matrix (e.g. 1:20,000) were separated and determined within 7 min using the coated support. The advantage of the present HPLC technique lies in the simultaneous separation and assay of total lanthanides and uranium whereas other analytical methods necessitate the separation of uranium matrix prior to lanthanide assay.