NRC-8, EuCheMS International Conference on Nuclear and Radiochemistry

TiO2 based absorber for uranium separation and 236U measurement with AMS

19 Sept 2012, 18:00

1h 50m

Como, Italy

Poster Radioactive elements in the environment, radiation archeometry and Health Physics Poster Session

Speaker

Dr Mojmir Nemec (Czech Technical University in Prague, Brehova 7, Prague 115 19, Czech Republic)

Description

The uranium separation from natural waters was studied at the Department of Nuclear Chemistry in late 80´s and early 90’s. TiO-PAN absorber (titanium dioxide embedded in polyacrylonitrile) showed high sorption capacity for this element. This composite absorber is planned to be used for uranium pre-concentration for measuring environmental 236U/U ratios by Accelerator Mass Spectrometry (AMS). After the preliminary AMS results showing anthropogenic contamination in TiO-PAN absorber, the preparation of titanium oxide was studied with a strong emphasis on elimination of this contamination. Hence, titanium dioxide materials were prepared from an organic uranium-free compound. These samples were then characterized for their crystal structure, their specific surface area, and their sorption towards uranium. Detailed sorption properties were determined also for TiO-PAN absorber including kinetic experiments, sorption isotherm, and effect of several ions (Ca2+; Mg2+; Fe3+; NO3-; SO42-; Cl-; CO32-). In these experiments, the uranium concentrations were measured by Time Resolved Laser Induces Fluorescence Spectrometry (TRLFS), which allows us to measure uranium concentrations up to ppb level. A strong influence of Cl- ions present in the solutions was seen, thus the calibration of TRLFS has to be made in order to determine the correct uranium concentration. Presently we are focusing on finding a water source which is not anthropogenically contaminated in order to use this water for further experiments and on the following separation and concentration steps for AMS sample preparation.