分类： 核科学技术 >> 核材料与工艺技术 提交时间： 2023-06-18 合作期刊: 《Nuclear Science and Techniques》
摘要： 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= 0.16 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-.
分类： 核科学技术 >> 核材料与工艺技术 提交时间： 2023-06-18 合作期刊: 《Nuclear Science and Techniques》
摘要： The adsorption behavior of 241Am(III) and Eu(III) by silica/polymer-based isoHex-BTP adsorbent (isoHex-BTP/SiO2-P) was investigated by a batch experiment method. isoHex-BTP/SiO2-P exhibited high affinity and selectivity for 241Am(III) over 152Eu(III) in 24 mol/dm3 nitric acid solutions. Within the experimental contact time range of 0.524 h, isoHex-BTP/SiO2-P showed high selectivity for 241Am(III) compared to 152Eu(III) in 3 mol/dm3 nitric acid solution. However, the adsorption kinetics of 241Am(III) and 152Eu(III) was slow. Eu(III) adsorption followed the pseudo-second-order kinetic model, indicating chemical adsorption as the rate-limiting step of the adsorption process. And the adsorption agreed well with the Langmuir adsorption model at various temperatures. The adsorption kinetics and isotherm data indicated that the equilibrium adsorption capacity, the adsorption rate, the maximum adsorption capacity and the adsorption affinity, increased with temperature. The thermodynamic parameters, negative change in Gibbs free energy, and positive change in enthalpy and entropy, suggested that the adsorption of Eu(III) was spontaneous and endothermic process with an increase of entropy.
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