Loading of some radionuclides on nano-sorbents for nuclear applications

The creation of a new generation of nano-sorbent materials with their exceptional characteristics of high surface area and high sorption capacity would lead to remarkable developments in the production of sealed radioactive sources. Two silver nano-structures were prepared namely silver metal NPF and silver oxide NPs. Different factors were studied to determine the ability of silver metal NPF and silver oxide NPs to sorb ¹³⁴Cs(I), ⁶⁰Co(II), and ¹³¹I. Silver metal NPF demonstrated a strong affinity to all radionuclides studied. Silver oxide NPs had a poor affinity to ¹³⁴Cs(I) and ⁶⁰Co(II), although it had a very strong affinity to sorb ¹³¹I. Both prepared nano-sorbents were characterized using different techniques such as FTIR, XRD, TGA, DTA, HRTEM, and EDX, which revealed that the prepared silver structures were of nano-scale size with an average particle size ≤ 20 nm for silver metal NPF and a primary particle size of ≤ 2nm with some agglomerated particles of average size approximately 12 nm for silver oxide NPs. Sorption experiments were performed, and the effects of solution ph, contact time, initial concentration of sorbate ions, and reaction temperature on the sorption process were investigated. By applying sorption models, it was found that in the case of silver metal NPF, the sorption kinetics of ¹³⁴Cs(I), ⁶⁰Co(II) and ¹³¹I were fitted to Elovich model, pseudo-second order, and pseudo-first-order model, respectively. The film diffusion mechanism was efficiently fitted to the sorption of both ¹³⁴Cs(I) and ¹³¹I in sorption diffusion models, while intra particle diffusion was the rate determining step for sorption of ⁶⁰Co(II). In the case of sorption isotherm models, the studied radionuclides obeyed to the Freundlich isothermal model. The Elovich model suited to the sorption kinetics of ¹³¹I on silver oxide NPs. Intra particle diffusion is the rate determining step for sorption ¹³¹I for the models of sorption diffusion. By applying the iso thermic sorption models, it was found that the sorption of ¹³¹I obeyed the Freundlich iso thermic model. The maximum sorption capacity of silver metal NPF for ¹³⁴Cs(I), ⁶⁰Co(II), and ¹³¹I, was found to be 153.94, 153.54, and 350 mg/g, respectively. As for ¹³¹I, silver oxide NPs had the unprecentated maximum sorption capacity found to be 1111 mg/g. ¹³⁴Cs(I) and ⁶⁰Co(II) radionuclides were applied to prepare a sealed radioactive source for the calibration of γ-detector. The quality control (QC) examinations were performed and the results given had proved the validity of the prepared sources for calibration of HPGe detectors. Two silver nano-structures were prepared, characterized and applied for the ¹³⁴Cs, ⁶⁰Co and ¹³¹I sorption. Silver metal NPF showed good affinity towards studied radionuclides and was applied as core material in the preparation of ¹³⁴Cs and ⁶⁰Co sealed radioactive source for calibration of the HPGe-γ detector. Silver oxide NPs showed unprecented affinity and high sorption capacity for ¹³¹I. It can be introduced as a promising core material for brachytherapy seed preparation, but further studies need to be applied.