可控辐射接枝制备二元咪唑离子液体固载硅基材料及其对锝的选择性吸附研究

Technetium is one of the fission products in spent fuel with high yield, long life and strong migration in the environment, which would causes long-term potential radioactive hazard to the ecological environment. Therefore, it is an urgent issue to selective separate technetium from spent fuel waste and environmental water. In order to improve the selective adsorption of technetium, the binary ionic liquid monomers, namely hydrophobic imidazolium ionic liquid and hydrophilic imidazole ionic liquid, will be co-grafted on mesoporous silica-based materials by means of combination of ionizing radiation technology and reversible addition-fragmentation chain transfer radical (RAFT) polymerization for adsorption separation of technetium. By changing the side chain structure of hydrophobic imidazolium cation and adjusting the proportion of hydrophilic-hydrophobic grafting chain, the adsorption behaviors of binary ionic liquid supported silica-based materials towards technetium and its simulated element rhenium will be systematically studied. The structure-performance relationship between structure and distribution of ionic liquid and adsorption performance will be investigated. The adsorption mechanism will be elucidated and the molecular structure of the adsorbent will be optimized. It is expected to obtain a new technetium adsorbent with high adsorption selectivity, rapid adsorption and radiation resistance. The completion of this work will provide important scientific supports for the development and application of highly efficient separation technology towards technetium.

锝是乏燃料中产额高、寿命长的裂变产物之一，在环境中有很强的迁移性，会对生态环境造成长期潜在的放射性危害，因此，需要对乏燃料废液和环境水相中的锝进行选择性分离。为了提高针对锝的选择性分离效果，本项目拟采用电离辐射技术和可逆加成-断裂链转移（RAFT）聚合法相结合在介孔硅基材料上可控共接枝二元离子液体，即疏水咪唑离子液体和亲水咪唑离子液体，用于锝吸附分离。通过改变疏水咪唑阳离子侧链结构、调节亲疏水性接枝链的比例，系统研究二元离子液体固载硅基材料对锝及其模拟元素铼的吸附行为，探讨离子液体结构、分布与吸附性能之间的构效关系，阐明吸附机理并优化吸附材料分子结构。预期获得一种具有高选择性、快速吸附和耐辐照性的新型锝吸附分离材料。本项目的完成将为推动高效分离锝技术的发展和应用提供重要的科学依据。

高锝酸根(TcO4-)会对生态环境造成长期的潜在放射性危害，因此从放射性废水中选择性分离TcO4-是一个迫切需要解决的问题。在本项目中，我们首次通过将亲水离子液体1-乙烯基-3-乙基咪唑溴化([C2VIm]Br)和疏水离子液体1-乙烯基-3-烷基咪唑([CnVIm]Br, n = 4,6,8,12)同时辐射可控接枝到二氧化硅上，研制了一系列二元离子液体功能化二氧化硅(SiO2-g-PC2-CnvimBr)去除ReO4-（作为TcO4-的类似物），一元离子液体功能化二氧化硅(SiO2-g-PC2vimBr)也被合成进行比较。考察了吸收剂量，RAFT试剂含量，二元离子液体配比对接枝收率的影响。SiO2-g-PC2-CnvimBr的选择性随疏水离子液体含量的增加和疏水咪唑烷基链长度的增加而增加。SiO2-g-PC2-CnvimBr在1000kgy下仍表现出优异的耐酸性和耐辐照性，对ReO4-的选择性优于SiO2-g-PC2vimBr。此外，研究并比较了疏水性咪唑不同烷基链长SiO2-g-PC2-CnvimBr对模拟放射性废水中ReO4-的连续吸附。发现它们的相对柱吸附容量和选择性随疏水咪唑烷基链长度的增加而增加。此外，SiO2-g-PC2-CnvimBr具有良好的可重用性。实验结果表明，SiO2-g-PC2-CnvimBr可以从放射性废水和TcO4污染地下水连续分离TcO4-/ReO4-，在实际应用中具有良好的应用前景。