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.

中文翻译：

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在硅铝酸钾地质聚合物中包封载锶钛酸盐废吸附剂

摘要 在福岛第一核电站现场，钛酸盐吸附剂已被用于去除受污染水中的 Sr 放射性同位素。这个过程会导致产生废吸附剂，这些吸附剂需要长期储存和处置的稳定性。地质聚合物是实现这种固结的基质的候选物。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，进行了浸出实验和对嵌入地质聚合物中的废钛酸盐吸附剂的 Sr 分布的观察，其中负载了实际浓度的 Sr。实验结果表明，在浸入去离子水中 360 天后，仅 0.75% 的 Sr 从负载有 30%（按固体重量）用过的吸附剂的 K-地质聚合物中浸出。通过电子显微镜和同位素显微镜观察 Sr 分布，Sr 保留在钛​​酸盐吸附剂中，没有扩散到地质聚合物基质中。从不含吸附剂的 K-地质聚合物中浸出 Sr（以相似浓度加载）也受到限制，浸出 360 天后仅为 0.05%。总之，K-地质聚合物基质中的钛酸盐吸附剂和 K-地质聚合物本身都为 Sr 固定提供了有吸引力的潜力。