Department of Environmental Engineering, Graduate School of Engineering, Kyoto University, Cluster C, Kyoto daigaku-Katsura, Nishikyo-ku, Kyoto, 615-8540, Japan.
Department of Environmental Engineering, Graduate School of Engineering, Kyoto University, Cluster C, Kyoto daigaku-Katsura, Nishikyo-ku, Kyoto, 615-8540, Japan.
Chemosphere. 2017 Nov;187:188-195. doi: 10.1016/j.chemosphere.2017.08.114. Epub 2017 Aug 23.
Environmentally sound treatments are required to dispose of municipal solid waste incineration fly ash (MSWIFA) contaminated with radioactive cesium (Cs) from the Fukushima Daiichi nuclear power plant accident in Japan. This study focuses on the stabilization of Cs using an alkali-activated MSWIFA and pyophyllite-based system. Three composite solid products were synthesized after mixtures of raw materials (dehydrated pyrophyllite, MSWIFA, 14 mol/L aqueous sodium hydroxide, and sodium silicate solution) were cured at 105 °C for 24 h. Three types of MSWIFAs were prepared as raw fly ash, raw fly ash with 0.1% CsCl, and raw fly ash with 40% CsCl to understand the stabilization mechanism of Cs. Cs stabilization in two solid products was successful, with less than 6.9% leaching observed from two types tests, and was partly successful for the solid product with the highest concentration of Cs. X-ray diffraction showed that all of the solid products produced several crystalline phases, and that pollucite was formed in the highest Cs concentration product. The X-ray absorption fine structure and scanning electron microscopy with X-ray analysis suggested that most Cs species formed pollucite in the two solid products from MSWIFA with added CsCl. This system provides a technique for the direct stabilization of Cs in MSWIFA.
需要采用环境友好的处理方法来处置福岛第一核电站事故中受放射性铯（Cs）污染的城市固体废物焚烧飞灰（MSWIFA）。本研究聚焦于利用碱激发 MSWIFA 和叶蜡石基体系稳定 Cs。将原料（脱水叶蜡石、MSWIFA、14 mol/L 氢氧化钠水溶液和硅酸钠溶液）混合物在 105°C 下固化 24 h 后，合成了 3 种复合固体产物。为了了解 Cs 的稳定化机制，制备了 3 种类型的 MSWIFA，分别为原始飞灰、含 0.1% CsCl 的原始飞灰和含 40% CsCl 的原始飞灰。两种类型的测试中，Cs 在两种固体产物中的浸出率均小于 6.9%，而对于 Cs 浓度最高的固体产物，Cs 的稳定化部分成功。X 射线衍射表明，所有固体产物均生成了几种结晶相，且在 Cs 浓度最高的产物中形成了钡沸石。X 射线吸收精细结构和带有 X 射线分析的扫描电子显微镜表明，在添加 CsCl 的 MSWIFA 中形成的两种固体产物中，大部分 Cs 以钡沸石的形式存在。该体系为 MSWIFA 中 Cs 的直接稳定化提供了一种技术。
