Zhang Zhi, Xue Yun, Yan Yong-De, Li Guo-Qiang, Xu Wen-Da, Ma Fu-Qiu, Liu Xin, Zhang Qing-Guo
Harbin Engineering University Harbin 150001 Heilongjiang P. R. China
China Institute for Radiation Protection Taiyuan 030006 Shanxi P. R. China.
RSC Adv. 2023 Jun 19;13(27):18347-18362. doi: 10.1039/d3ra02723f. eCollection 2023 Jun 15.
With the development of nuclear energy, spent cationic exchange resins after purification of radioactive wastewater must be treated. Molten-salt oxidation (MSO) can minimize the disposal content of resins and capture SO. In this work, the decomposition of uranium-containing resins in carbonate molten salt in N and air atmospheres was investigated. Compared to N atmosphere, the content of SO released from the decomposition of resins was relatively low at 386-454 °C in an air atmosphere. The SEM morphology indicated that the presence of air facilitated the decomposition of the resin cross-linked structure. The decomposition efficiency of resins in an air atmosphere was 82.6% at 800 °C. The XRD analysis revealed that uranium compounds had the reaction paths of UO → UO → UO and UO → KUO → KUO in the carbonate melt, and sulfur elements in resins were fixed in the form of KNa(SO). The XPS result illustrated that peroxide and superoxide ions accelerated the conversion of sulfone sulfur to thiophene sulfur and further oxidized to CO and SO. Besides, the ion bond formed by uranyl ions on the sulfonic acid group was decomposed at high temperature. Finally, the decomposition of uranium-containing resins in the carbonate melt in an air atmosphere was explained. This study provided more theoretical guidance and technical support for the industrial treatment of uranium-containing resins.
随着核能的发展，放射性废水净化后用过的阳离子交换树脂必须进行处理。熔盐氧化（MSO）可以减少树脂的处置量并捕获SO。在这项工作中，研究了含铀树脂在氮气和空气气氛中于碳酸盐熔盐中的分解情况。与氮气气氛相比，在空气气氛中386 - 454℃下树脂分解释放的SO含量相对较低。扫描电子显微镜（SEM）形态表明，空气的存在促进了树脂交联结构的分解。在800℃时，树脂在空气气氛中的分解效率为82.6%。X射线衍射（XRD）分析表明，铀化合物在碳酸盐熔体中有UO→UO→UO和UO→KUO→KUO的反应路径，树脂中的硫元素以KNa(SO)的形式固定。X射线光电子能谱（XPS）结果表明，过氧化物和超氧离子加速了砜硫向噻吩硫的转化，并进一步氧化为CO和SO。此外，磺酸基团上由铀酰离子形成的离子键在高温下分解。最后，解释了含铀树脂在空气气氛中于碳酸盐熔体中的分解过程。该研究为含铀树脂的工业处理提供了更多的理论指导和技术支持。
