RadChem 2010

Radiation stability and extraction properties of thiacalixarenes

22 Apr 2010, 05:30

15m

Red (Casino Conference Centre)

Verbal Radiation Chemistry Radiation Chemistry

Speaker

Irena Špendlíková (KJCH FJFI CVUT)

Description

This study deals with the effects of irradiation on the stability and extraction properties of thiacalixarenes ¹, the prospective liquid-liquid extractants for the extraction of actinides and lanthanides from aqueous solutions. Thiacalixarenes dissolved in various organic diluents were irradiated with ⁶⁰Co γ rays or accelerated electrons with energy of 4.5 MeV. The absorbed doses ranged from 0 to 100 kGy. Possible effect of the presence of aqueous phase during irradiation was also investigated. The extraction properties were studied in synergistic systems. The aqueous phase consisted of a solution of cosane (chloro-protected bis(1,2-dicarbollide) cobaltic acid) in 0.1 mol/L nitric acid; solutions of thiacalixarenes in nitrobenzen or 1,2-dichlorethane were used as the organic phase. Distribution ratios D for ¹⁵²Eu and ²⁴¹Am and their mutual separation factors were evaluated. The concentration of thiacalixarene in the irradiated samples was measured using HPLC and the activity of aqueous and organic phase was measured by γ spectrometer with HPGe detector. The results confirmed previously published data ² which showed a strong synergistic effect in the systems containing thiacalixarenes and cosanes. This effect depends on substituents at the lower and/or upper rim. It was demonstrated that the synergic effect is independent of the used type of cosane (chloro-, resp. bromo-protected bis(1,2-dicarbollide) cobaltic acid or bis(1,2-dicarbollide) cobaltic acid) and it strongly depends on the diluent used in the organic phase. The studied systems proved not to be very stable towards the radiation. After irradiation with the dose of 20 kGy, the distribution ratios dropped to one half for thicalixarene solutions in nitrobenzene; they dropped even to one tenth for dichlorethane solutions at the same dose. This work was performed under the auspices of Czech Science Foundation grant GACR 104-07-1242 and Ministry of Education, Youth and Sports grant MSM 6840770020. REFERENCES 1. Lhoták P.: Eur. J. Org. Chem. 8, 1675 (2004). 2. Kyrš M.: J. Radioanal. Nucl.Chem, 245, 455 (2002).