Kim Jimin, Lee Keunyoung, Seo Bum-Kyoung, Hyun Jae-Hyuk
Environmental Research Division, Daejeon Metropolitan City Institute of Health and Environment, 407, Daehak-ro, Yuseong-gu, Daejeon, 34057, Republic of Korea.
Decommissioning Technology Research Division, Korea Atomic Energy Research Institute, 111, Daedeok-daero 989beon-gil, Yuseong-gu, Daejeon, 34142, Republic of Korea.
Environ Res. 2020 Dec;191:110099. doi: 10.1016/j.envres.2020.110099. Epub 2020 Aug 29.
A composite adsorbent for the removal of radioactive cesium (Cs) was synthesized by immobilizing potassium cobalt ferrocyanide in the micro pores of the zeolite chabazite. The synthetically optimized composite adsorbent demonstrates a rapid cesium adsorption rate under both salt-free and high-salt conditions with a high distribution coefficient of cesium (≥10 mL/g). Although both components have the same ion-exchange reaction between potassium and cesium, the reaction by ferrocyanide component was predominant, which derived hundred times higher distribution coefficient of the composite adsorbent than that of pure chabazite. A thermal stabilization process was studied for improving the storage and/or disposal stability of the spent adsorbent. The formation of a eutectic system within the spent adsorbent reduced the stabilization temperature to 1000 °C from 1200 °C. Accordingly, the leaching of cesium was remarkably reduced by the remineralization to the stable pollucite. The stable impregnation of ferrocyanide component in the chabazite pores derived the reduction of cesium volatility enabling the high temperature stabilization method. Our experimental results provide evidence that the composite adsorbent has clear advantages on the cesium removal from contaminated water and its stabilization via thermal-treatment.
通过将亚铁氰化钾固定在菱沸石的微孔中，合成了一种用于去除放射性铯（Cs）的复合吸附剂。经合成优化的复合吸附剂在无盐和高盐条件下均表现出快速的铯吸附速率，铯的分配系数较高（≥10 mL/g）。尽管两种成分在钾和铯之间具有相同的离子交换反应，但亚铁氰化物成分的反应占主导地位，这使得复合吸附剂的分配系数比纯菱沸石高出百倍。研究了一种热稳定化工艺，以提高废吸附剂的储存和/或处置稳定性。废吸附剂中形成共晶体系将稳定化温度从1200℃降至1000℃。因此，通过再矿化形成稳定的方沸石，铯的浸出显著减少。亚铁氰化物成分在菱沸石孔中的稳定浸渍使得铯的挥发性降低，从而实现了高温稳定化方法。我们的实验结果证明，复合吸附剂在从污染水中去除铯及其通过热处理实现稳定化方面具有明显优势。
