Encapsulation of Sr-loaded titanate spent adsorbents in potassium aluminosilicate geopolymer
Encapsulation of Sr-loaded titanate spent adsorbents in potassium aluminosilicate geopolymer
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DOI：
10.1080/00223131.2020.1775717
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发表时间：
2020-06
影响因子：
1.2
通讯作者：
N. Soonthornwiphat;Yutaro Kobayashi;K. Toda;K. Kuroda;Chaerun Raudhatul Islam;T. Otake;Y. Elakneswaran;J. Provis;Tsutomu Sato
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文献类型：
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作者：
N. Soonthornwiphat;Yutaro Kobayashi;K. Toda;K. Kuroda;Chaerun Raudhatul Islam;T. Otake;Y. Elakneswaran;J. Provis;Tsutomu Sato
摘要钛酸盐吸附剂已用于去除福岛第一核电站污染水中的Sr放射性同位素。该过程导致产生废吸附剂，其需要稳定化以用于长期储存和处置。地质聚合物是实现这种固结的基质的候选者。然而，需要更多的数据来评估Sr从嵌入地质聚合物基质中的吸附剂中的浸出行为。在这项研究中，浸提实验和观察的Sr分布的废钛酸盐吸附剂嵌入在地质聚合物，负载在现实浓度的Sr进行。实验结果表明，只有0.75%的锶浸出的K-地质聚合物负载30%（固体重量）的废吸附剂后，在去离子水中浸泡360天。从电子和同位素显微镜观察Sr分布，Sr保留在钛酸盐吸附剂，并没有扩散到地质聚合物基质。从没有吸附剂的K-地质聚合物中浸出Sr（以类似浓度负载）也是有限的，在浸出360天后仅为0.05%。总之，钛酸盐吸附剂在K-地质聚合物矩阵，和K-地质聚合物本身，提供了一个有吸引力的潜力Sr固定。
ABSTRACT Titanate adsorbents have been used to remove Sr radioisotopes from contaminated water at the Fukushima Daiichi Nuclear Power Station site. This process leads to the generation of spent adsorbents, which require stabilization for long term storage and disposal. Geopolymers are candidates for matrices to achieve this consolidation. However, more data are needed to assess the leaching behavior of Sr from the adsorbents embedded in a geopolymer matrix. In this study, leaching experiments and observations of the Sr distribution of spent titanate adsorbent embedded in geopolymers, loaded with Sr at realistic concentrations were conducted. The experimental results illustrate that only 0.75% of the Sr was leached out from a K-geopolymer loaded with 30% (by solid weight) of spent adsorbent after 360 days of immersion in deionized water. From the observations of Sr distributions by electron and isotope microscopy, Sr remained in the titanate adsorbent and did not diffuse into the geopolymer matrix. Leaching of Sr (loaded at a similar concentration) from the K-geopolymer without the adsorbent was also limited, only 0.05% after 360 days of leaching. In conclusion, both titanate adsorbent in K-geopolymer matrix, and the K-geopolymer itself, offer an attractive potential for Sr immobilization.