Sorption of cesium and gadolinium ions onto zirconium silico antimonate sorbent from aqueous solutions

Using a batch equilibrium technique, the sorption of ¹³⁷Cs and ¹⁵³Gd onto synthesized zirconium silico antimonate (ZrSiSb) sorbent was examined. The new sorbent was prepared by precipitation technique and characterized by diverse analytical tools. The influence of shaking time, pH, metal ion concentrations, temperature, and a real sample was carried out. The data indicate that ZrSiSb has a very fast equilibrium time (30 min). The distribution coefficient values as a function of pH have sequence order; Cs(I) > Gd(III). The reaction kinetic obeys the pseudo-2^nd-order model. The saturation capacity is 69.8 and 27.2 mg/g for Cs(I) and Gd(III), respectively. Equilibrium data were analyzed by various sorption isotherm models. Desorption studies showed that the best eluents for complete recovery (about 99%) of the selected ions are KCl for Cs(I) and CaCl₂ for Gd(III). The sorption effectiveness of the new ZrSiSb to remove ¹³⁷Cs and ¹⁵³Gd from real low-level radioactive waste was examined. The results obtained showed that the prepared new composite can be applied as a hoped sorbent material to get rid of these radionuclides from different wastewaters.

Practical aspects of 153Gd as a radioactive source for use in brachytherapy

The goal of this study was to investigate the production, purification and immobilization techniques for a ¹⁵³Gd brachytherapy source. We have investigated the maximum attainable specific activity of ¹⁵³Gd through the irradiation of Gd₂O₃ enriched to 30.6% ¹⁵²Gd at McMaster Nuclear Reactor. The advantage of producing ¹⁵³Gd through this production pathway is the possibility to irradiate pre-sealed pellets of ¹⁵²Gd enriched Gd₂O₃, thereby removing the need to perform chemical separation with large quantities of radio-impurities. However, small amounts of long-lived impurities are produced from the irradiation of enriched ¹⁵²Gd targets due to traces of Eu in the sample. If the amount of impurities produced is deemed unacceptable, ¹⁵³Gd can be isolated as an aqueous solution, chemically separated from impurities and loaded onto a sorbent with a high affinity for Gd before encapsulation.

A non-aqueous reduction process for purifying ¹⁵³Gd produced in natural europium targets

Gadolinium-153 is a low-energy gamma-emitter used in nuclear medicine imaging quality assurance. Produced in nuclear reactors using natural Eu₂O₃ targets, ¹⁵³Gd is radiochemically separated from europium isotopes by europium reduction. However, conventional aqueous europium reduction produces hydrogen gas, a flammability hazard in radiological hot cells. We altered the traditional reduction method, using methanol as the process solvent to nearly eliminate hydrogen gas production. This new, non-aqueous reduction process demonstrates greater than 98% europium removal and gadolinium yields of 90%.