自掺杂型锑氧化物材料的制备、表征及其对Sr(Ⅱ)的吸附性能

Preparation, Characterization and Sr(Ⅱ) Adsorption Performance of Self-Doped Antimony Oxide

90Sr是核电站放射性废液中需要重点去除的核素之一,水合锑氧化物Sb2O5·mH2O可以在酸性条件下选择性吸附脱除90Sr.本文在以醇为溶剂的无水体系中,以化学性能较稳定且毒性低的SbCl3为原料,以紫外线照射辅助双氧水氧化及控制水解两步法制备出自掺杂型锑氧化物Sb(Ⅲ)/Sb2O5.文中采用X射线光电子能谱(XPS)、X射线衍射(XRD)和傅里叶变换红外(FTIR)光谱对材料结构进行结构表征,并采用批量实验方法研究不同Sb(Ⅲ)/Sb(total)比例与Sr(Ⅱ)吸附性能的相关性,以及溶液pH值对Sr(Ⅱ)吸附性能的影响.实验结果表明:Sb(Ⅲ)可在较大的比例范围内共存于立方烧绿石型Sb2O5晶格内,形成良好的固溶体Sb(Ⅲ)/Sb2O5;制备过程中通过控制醇溶剂的类型、氧化剂的添加方式以及两步反应温度,可以获得具有不同氧化率,即不同Sb(Ⅲ)/Sb(total)比例的Sb(Ⅲ)/Sb2O5材料;其中Sb(Ⅲ)/Sb(total)比例为49.8%的锑氧化物材料吸附性能最好,在纯水体系下对Sr(Ⅱ)的分配系数为6.6×107mL·g-1,在pH=3-13范围内对Sr(Ⅱ)具有良好的吸附性能,并且在本文实验条件下,Sr(Ⅱ)在锑氧化物材料上的吸附更好地符合Langmuir吸附模型.

^90Sr is an important radionuclide that needs to be removed from radioactive waste water （RWW） in nuclear power plants （NPP） prior to its discharge into the environment. Hydrous antimony oxide is a type of selective adsorbent for Sr（Ⅱ） ions, especially in acid solution. In this paper, a series of self-doped hydrous antimony oxides Sb（Ⅲ）/Sb205 were prepared by a two-step process in an absolute alcohol solvent, using antimony trichloride as a stable and low-toxic antimony source and H2O2 solution as an oxidant. UV radiation was used to enhance the oxidation rate of Sb（Ⅲ）. The as-prepared samples were characterized by X-ray diffraction （XRD）, X-ray photoelectron spectroscopy （XPS）, and Fourier transform infrared （FTIR） spectroscopy analyses, and the effect of the preparation conditions on the composition and structure of the products are discussed. Batch adsorption experiments were performed to study the relationship between the Sb（Ⅲ）/Sb（total） ratio in the oxide adsorbent and the Sr（Ⅱ） adsorption activity. Moreover, the influence of the initial pH of the waste water was investigated. The results showed that Sb（Ⅲ） ions can coexist with Sb（V） and form the solid solution of Sb（Ⅲ）/Sb2O5 with cubic pyrochlore structure. Materials with different Sb（Ⅲ）/Sb（total） ratios can be obtained by choosing different alcohols as the solvent and a suitable mixing method of the reactants, as well as by changing the reaction temperature during the oxidation process. Among the as-prepared Sb（Ⅲ）/Sb2O5 adsorbents, the sample with a Sb（Ⅲ）/Sb（total） ratio of 49.8% showed the best Sr（Ⅱ） adsorption performance, and the distribution coefficients of Sr（Ⅱ） was about 6.6×107mL·g^-1 This hydrous antimony oxide showed favorable performance in the wide pH value of pH=3-13. In addition, Sr（Ⅱ） adsorption on the as-prepared material fitted the Langmuir model very well under the conditions studied.