Thermal stabilization of extraframework Cs+ in zeolite 13X
Thermal stabilization of extraframework Cs+ in zeolite 13X
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DOI：
10.1016/j.jnucmat.2022.154078
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发表时间：
2022-10-17
影响因子：
3.1
通讯作者：
Jeong, Hoon Young
中科院分区：
文献类型：
--
作者：
Park, Minji;Kim, Sookyoung;Jeong, Hoon Young
考虑到离子交换的可逆性质，对Cs+交换的沸石13 X进行热处理以安全地保留骨架外Cs+。通过热重-差示扫描量热仪（TG-DSC）分析，指示相变的吸热峰和放热峰在Cs+的较高表面负载下逐渐向较高温度移动（即，[Cs+]（0）/[NaX]（0）），表明骨架外Cs+稳定了沸石骨架。通过在= 900摄氏度的热处理，体相分析，如XRD，扫描电子显微镜，和表面积测量表明，沸石骨架完全打破，形成无孔相。XAS分析进一步表明，Cs+在900 ℃时主要结合到非晶相中，在>= 1，000 ℃时主要结合到铯榴石中。这与>= 900摄氏度处理的样品的明显低的Cs+浸出一致。由于铯榴石可以提供最大的Cs+的保留性，热处理导致其形成之前，建议在核废料处置库储存Cs+交换沸石13 X。(c)2022 ElsevierB.V.版权所有。
Given the reversible nature of ion exchange, Cs+-exchanged zeolite 13X was thermally treated to safely retain extraframework Cs+. By thermal gravimetric-differential scanning calorimeter (TG-DSC) analysis, both endothermic and exothermic peaks, indicative of phase transitions, gradually shifted to higher temperatures at the higher surface loading of Cs+ (i.e., [Cs+](0)/[NaX](0)), indicating that extraframework Cs+ stabilized the zeolite framework. By thermal treatment at = 900 degrees C, bulk-phase analyses such as XRD, scanning electron microscopy, and surface area measurement showed that the zeolite framework completely broke down to form nonporous phases. The XAS analysis further indicated that Cs+ was mainly incorporated into amorphous phases at 900 degrees C and pollucite at >= 1,000 degrees C. This was consistent with the markedly low Cs+ leaching for the >= 900 degrees C-treated samples. Since pollucite can provide the greatest retainability of Cs+, the thermal treatment leading to its formation is recommended before storing Cs+ -exchanged zeolite 13X at nuclear waste repositories. (c) 2022ElsevierB.V. Allrightsreserved.