Adsorption characteristics of strontium on synthesized antimony silicate
Adsorption characteristics of strontium on synthesized antimony silicate
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DOI：
10.1016/j.cej.2015.04.145
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发表时间：
2015-10
影响因子：
15.1
通讯作者：
Lan Zhang;Wei Jiying;Xuan Zhao;Fuzhi Li;Feng Jiang
中科院分区：
文献类型：
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作者：
Lan Zhang;Wei Jiying;Xuan Zhao;Fuzhi Li;Feng Jiang
放射性锶（90 Sr）是核电站低放废水中的主要污染物之一。硅酸锑被认为是一种选择性去除90 Sr的无机吸附剂。本文研究了一种安全的硅酸锑吸附剂的制备方法。在合成过程中，使用稳定且低毒的三氯化锑（SbCl 3）代替挥发性的五氯化锑（SbCl 5）作为锑源。除了具有结晶良好的烧绿石结构的富Sb相之外，可以检测到具有非晶结构的富Si相，这可能由于其大的比表面积而促进锶吸附。批实验表明，合成的材料可以提供一个良好的吸附Sr（II）在较宽的pH值范围为1.2-11和广泛的共存离子的浓度范围。当Si/Sb比为2.9时，Kd值最高，接近108 mL/g。钙离子对锶的吸附有显著的负面影响。当Ca ~（2+）浓度为0.1M时，Kd值降至102 mL/g。硅酸锑对Sr（II）的吸附动力学符合准二级动力学模型，吸附等温线符合Freundlich模型。热力学研究表明，吸附是一个吸热的自发过程。
Radioactive strontium (90Sr) is one of the major contaminants in low-level radioactive wastewaters from nuclear power plants. Antimony silicate is regarded as a selective inorganic adsorbent for90Sr removal. In this paper, a safe method was developed to prepare antimony silicate adsorbents. In the synthetic process, stable and low-toxic antimony trichloride (SbCl3) was used as an antimony source instead of volatile antimony pentachloride (SbCl5). Besides an Sb-rich phase with well-crystalized pyrochlore structure, an Si-rich phase with amorphous structure can be detected, which may facilitate strontium adsorption due to its large specific surface area. The batch experiments demonstrate that the synthesized material can offer a favorable adsorption of Sr(II) over a broad pH range of 1.2–11 and a wide concentration range of co-existing ions. The highestKdvalue amounts to nearly 108mL/g at an Si/Sb ratio of 2.9. Calcium ions have a significant negative influence on strontium adsorption. TheKdvalue drops to 102mL/g at a Ca2+concentration of 0.1 M. The kinetic performance of Sr(II) adsorption onto antimony silicate follows the pseudo-second-order model and the adsorption isotherms coincide well with the Freundlich model. Moreover, the thermodynamic study reveals that the adsorption is an endothermic and spontaneous process.