Subjects: Nuclear Science and Technology >> Nuclear Materials and Techniques submitted time 2023-06-18 Cooperative journals: 《Nuclear Science and Techniques》
Abstract： To isolate and separate thorium from nitric acid solutions, three silica-based anion exchange resins were synthesized. Batch experiments were carried out to investigate adsorption behavior of thorium in nitric acid solutions. Adsorption at different concentrations of nitric acid and thorium, influence of contact time and coexisting metal ions, and effect of NO3- were investigated in detail. It was found that at high HNO3 concentrations, the resins exhibited higher adsorption capacity and better affinity towards thorium. The adsorption kinetics could be described by the pseudo-second order model equation, while the adsorption isotherms were well correlated by the Langmuir model. The maximum capacity towards thorium species on SiPyR-N4 was evaluated at 27–28 mg/g-resin. The thermodynamic parameters indicated the adsorption was an exothermic reaction. The presence of NO3- was found to promote the retention of the thorium species.
Subjects: Nuclear Science and Technology >> Nuclear Materials and Techniques submitted time 2023-06-18 Cooperative journals: 《Nuclear Science and Techniques》
Abstract： A new anion exchanger with pyridine groups was prepared by grafting of 2-vinyl pyridine onto polypropylene (PP) nonwoven fabrics by pre-irradiation grafting technique, followed by quaternization of pyridine rings in grafted chains in reaction with bromoethane. The results showed that the grafting yield increased with the monomer concentration and conversion ratio of quaternization increased with the time. The grafted and quaternized fabrics were characterized by FT-IR, DSC, SEM and ICP. The possibility of adsorption of perrhenate (ReO4-), a nonradioactive analogue to pertechnetate (99TcO4-), from aqueous solution by anion exchanger was investigated. The experiments performed at pH= 0.1–6 showed that pH=2.2 was the optimal acidity for ReO4- adsorption, and an adsorption equilibrium was achieved in 30 min. The reaction enthalpy was -12.55 kJ/mol, indicating that the adsorption process is exothermic. XPS tests indicated that the ReO4- uptake was a typical ion exchange between Cl- on anion exchanger and ReO4-.
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