Jin Qiang, Diao Xinya, Fan Ye, Hao Lecun, Chen Zongyuan, Guo Zhijun
MOE Frontiers Science Center for Rare Isotopes, Lanzhou University, Lanzhou 730000, China.
Radiochemistry Laboratory, School of Nuclear Science and Technology, Lanzhou University, Lanzhou 730000, China.
ACS Omega. 2024 Jul 12;9(29):32011-32020. doi: 10.1021/acsomega.4c03806. eCollection 2024 Jul 23.
Due to the significant selectivity for Cs, ammonium molybdophosphate (AMP) possesses potential to uptake radiocesium from high-level liquid waste (HLLW), whereas its micro-crystalline structure and fine powder morphology limit its industrial application. Although the granulation method with alginate is prospective for the preparation of an AMP exchanger, the mechanical strength of obtained beads may be insufficient for application. In this context, we prepared silica-reinforced AMP-calcium alginate (ACS) beads and evaluated their performance for Cs removal from strong acidic solutions. It was found that the addition of silica in the fabrication significantly improved the mechanical strength of the beads in comparison to those without silica. Notably, the beads with an AMP/silica mass ratio of 1.0 exhibited an exceptional mechanical strength, surpassing that of ACS beads composed of other components. The batch experiment results indicated that the Cs adsorption follows a non-linear pseudo-second-order rate equation. The distribution coefficient of Cs was high even in extreme acidic conditions (∼1.6 × 10 mL/g in 8.0 mol/L HNO solution). The Cs adsorption can be well fitted with the Langmuir model, and the estimated maximum exchange capacity in 3.0 mol/L HNO could reach 23.9 mg/g. More importantly, ACS beads showed excellent selectivity toward Cs uptake over eight co-existing metal ions in simulated HLLW, with separation factor values all above 145. The column experiment exhibited that the beads can serve as the stationary phase in columns to effectively remove Cs. The findings of this study are significant as they provide insights into the development of efficient materials for radiocesium removal from high-level liquid waste. The results demonstrate the potential of silica-reinforced ACS beads for Cs adsorption, with promising applications in industrial settings.
由于对铯具有显著的选择性，钼酸铵磷酸盐（AMP）有从高放废液（HLLW）中摄取放射性铯的潜力，但其微晶结构和细粉形态限制了其工业应用。尽管用海藻酸盐造粒的方法对于制备AMP离子交换剂很有前景，但所得珠子的机械强度可能不足以用于实际应用。在此背景下，我们制备了二氧化硅增强的AMP-海藻酸钙（ACS）珠子，并评估了它们从强酸性溶液中去除铯的性能。结果发现，与不含二氧化硅的珠子相比，在制备过程中添加二氧化硅显著提高了珠子的机械强度。值得注意的是，AMP/二氧化硅质量比为1.0的珠子表现出非凡的机械强度，超过了由其他成分组成的ACS珠子。批量实验结果表明，铯的吸附遵循非线性伪二级速率方程。即使在极端酸性条件下（在8.0 mol/L HNO溶液中约为1.6×10 mL/g），铯的分配系数也很高。铯的吸附可以很好地用朗缪尔模型拟合，在3.0 mol/L HNO中估计的最大交换容量可达23.9 mg/g。更重要的是，ACS珠子在模拟高放废液中对铯的摄取表现出对八种共存金属离子的优异选择性，分离因子值均高于145。柱实验表明，这些珠子可以作为柱中的固定相有效地去除铯。本研究的结果具有重要意义，因为它们为开发从高放废液中去除放射性铯的高效材料提供了见解。结果证明了二氧化硅增强的ACS珠子对铯吸附的潜力，在工业环境中有广阔的应用前景。
