Separation and purification of 131I from tellurium material using ion exchange for preparing tetra-butyl ammonium iodide (131I)

Fast-response flow-based method for evaluating 131I from biological and hospital waste samples exploiting liquid scintillation detection

This paper presents a fast and automatic flow-based method to extract ¹³¹I from biological samples and hospital waste, previous to liquid scintillation detection. ¹³¹I is a radionuclide extensively used in Nuclear Medicine due to their beta and gamma disintegrations, whereby hospitals have to manage the associated waste generation. The automatic developed system is based on Lab-On-Valve (LOV) flow-technique exploiting Cl-resin (135 mg per extraction). This methodology allows performing sample extractions and measurements on the same day, since the extraction frequency takes 1.4-4 h^-1, depending on the analysed sample volume, plus up to 2 h of measurement for each vial. ¹³¹I is retained as iodine ion and eluted with sodium sulphide 0.2 mol L^-1. The maximum sample volume that can be preconcentrated is 20 mL, reaching an extraction efficiency of 85 ± 5%. The minimum detectable activity (MDA) is 0.05 Bq, showing a precision of 7% RSD (n = 5). Both, biological samples (urine and saliva) and hospital waste samples can be satisfactorily analysed by the proposed system, obtaining recoveries between 90 and 110%. The developed method is then suitable to implement in hospitals, improving the surveillance of the ¹³¹I environmental release.

Batch and column adsorption behaviors of Se(IV) and Te(IV) on organic and inorganic ion exchangers from HCl solutions

Adsorption behaviors of Se(IV) and Te(IV) on the inorganic ion exchanger ceric tungstate (CeW) was studied under static and dynamic conditions and compared with the adsorption on the organic cation and anion exchangers Dowex-50X8 and AG-2X8, respectively. The radioactive isotopes 75Se and 123mTe were used to trace the respective elements. Some parameters affecting the adsorption were investigated under static conditions. In the case of batch technique the adsorption was studied from slightly acidic HCl as well as slightly alkaline media, i.e. at two pH-ranges. Se(IV) and Te(IV) were adsorbed on both the inorganic ion exchanger (CeW) and on AG-2X8, from slightly alkaline solutions. From the similarity of adsorption on both ion exchangers it was clear that (CeW) acts as an anion exchanger. Moreover, the obtained Kd-values for the adsorption on (CeW) were much higher than those for the adsorption on the organic anion exchanger AG-2X8. Se(IV) was not adsorbed on Dowex-50X8 all over the studied pH-range whereas Te(IV) was slightly adsorbed. Loading and elution behaviors of Se(IV) and Te(IV) on columns of AG-2X8 and (CeW) were studied using solutions of HCl of different concentrations. Some good separation alternatives of Se(IV) and Te(IV) under certain conditions were achieved.