共辐照接枝合成胺基型吸附剂对放射性废液中离子态和胶体态110Agm的去除

Co-irradiation Grafted Synthesis of Amine-based Adsorbent for Removal of Ion- and Colloid-state 110Agm in Radioactive Wastewater

  • 摘要: 在核电厂正常运行所产生的放射性废液中,放射性核素110Agm的形态复杂,除盐床无法将其彻底去除,研究其高效去除技术具有重要意义。本研究提出了以胺基型新材料PP-g-GMA@EDA为吸附剂的吸附分离方法实现对离子态(Ag(Ⅰ))和胶体态银(Ag·Nps)的共去除。采用γ射线诱导的共辐照接枝法制备了PP-g-GMA@EDA,并通过批式实验分别研究了其对Ag·Nps和Ag(Ⅰ)的去除性能及吸附机理。结果显示,在不同pH的Ag·Nps溶液中,PP-g-GMA@EDA较核电厂常用的商业树脂IRN9766具有更好的去除效率,溶液pH作用下的吸附曲线呈典型的阴离子交换吸附特征。在最佳pH=4条件下,材料对Ag·Nps的吸附效率可达100%,最大吸附量为101.44 mg/g。对于Ag(Ⅰ)的吸附,PP-g-GMA@EDA呈螯合吸附特征,在420 min达到吸附平衡。批式实验证实了胺基型吸附剂PP-g-GMA@EDA在放射性废液中多形态110Agm去污的适用性,为110Agm从放射性废液中去除提供了一种高效、可持续和工业上可行的方法。

     

    Abstract: The form of radionuclide 110Agm in the radioactive wastewater generated from the normal operation of nuclear power plants is complex, and it cannot be completely removed by desalting bed. The wastewater containing 110Agm will put pressure on the radioactive purification system and increase the consumption of resin so that lead to the increase of processing costs due to the increased radioactive solid waste. In addition, 110Agm could be discharged into the environment along with the liquid waste, which can accumulate in marine organisms through the food chain, so it is of great significance to study the removal of 110Agm as one of the main radionuclides in radioactive wastewater of nuclear power plants. In this study, a new amine-type material PP-g-GMA@EDA was synthesized by radiation induced simultaneous grafting of glycidyl methacrylate (GMA) onto polypropylene (PP) nonwovens followed by chemical modification with the ethanediamine (EDA), the EDA content on PP-g-GMA@EDA was 1.33 mmol/g, and the chemical structure was confirmed by ATR spectra. And then the PP-g-GMA@EDA was used as adsorbent to removal Ag·Nps and Ag(Ⅰ) in solution. The results show that in Ag·Nps solutions with different pH values, PP-g-GMA@EDA has better removal efficiency than IRN9766, a commercial resin commonly used in nuclear power plants. The adsorption curve under the action of pH of the solution shows typical anion exchange adsorption characteristics. Under the optimal pH=4, the adsorption efficiency of Ag·Nps can reach 100% under its initial concentration at 0.87 mg/g, and the maximum adsorption capacity is 101.44 mg/g. The results of X-ray diffraction (XRD) and scanning electron microscopy (SEM) characterization methods confirme the successful adsorption of Ag·Nps on PP-g-GMA@EDA. For the adsorption of Ag(Ⅰ), PP-g-GMA@EDA is more suitable in low and medium acidity, and shows chelating adsorption characteristics and reaches adsorption equilibrium in 420 min. The results of pseudo-first-order dynamics model and pseudo-second-order kinetics model show that the pseudo-second-order dynamics model can effectively simulate the adsorption process of Ag(Ⅰ) on PP-g-GMA@EDA. The results of batch adsorption experiments confirm the applicability of the amine-type adsorbent PP-g-GMA@EDA for multi-form 110Agm decontamination in wastewater, providing an efficient, sustainable and industrially feasible method for the removal of 110Agm from radioactive wastewater.

     

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