抗污损型金属有机框架水凝胶的制备及海水提铀性能研究

Based on the strategic value of uranium and the limitation of uranium mineral resources, the extraction of uranium from seawater, as a recharge of traditional ore-type uranium resources, is of great significance to support the rapid development of China's nuclear power industry. This project intends to introduce the concept of balanced charge polyelectrolyte with antifouling properties, which controlling the proportion of oppositely charged polyelectrolytes and cross-linking with different metal ions to form a polyelectrolyte hydrogel material, and then in situ reacting with the ligand to form a metal organic framework polyelectrolyte hydrogel with anti-bioadhesion as uranium adsorption material. The relationship between different metal organic framework polyelectrolyte hydrogel adsorbents and their adsorption properties will be investigated. The competitive experiments between uranyl ions and coexisting ions in simulated seawater will be carried out to confirm the selectivity of the adsorbents. Combining theoretical calculations with the spectra of the adsorbents before and after uranium adsorption, the adsorption mechanisms of uranyl ions on the hydrogels will be investigated. This study is instructive for the controlled synthesis, structure-activity relationship and anti-fouling mechanisms of metal-organic framework polyelectrolyte hydrogel uranium adsorbent, and provides ideas for the development of novel high-efficiency materials to extract uranium from seawater.

基于铀的战略价值以及铀矿产资源的有限性，从海水中提取铀作为传统矿石类铀资源的补给，对于支撑我国核电事业的快速发展具有重要意义。本项目拟引入具有防污性能的平衡电荷聚电解质，通过调控带相反电荷的聚电解质的比例，并与不同金属离子交联形成聚电解质水凝胶材料，再与配体反应，原位形成兼有抗生物粘附作用的金属有机框架聚电解质水凝胶铀吸附材料；考察不同金属有机框架聚电解质水凝胶吸附材料与其吸附性能的关系；开展在模拟海水条件下吸附材料对铀酰离子和共存离子的竞争吸附实验；结合理论计算及吸附剂吸附铀酰离子前后的光谱学数据，探讨金属有机框架聚电解质水凝胶对铀酰离子的吸附机理。该研究对金属有机框架聚电解质水凝胶铀吸附剂的可控合成、构效关系和防污机制具有指导意义，为发展新型高效海水提铀材料提供思路。

本项目构筑了具有水稳定性、分级孔隙率和抗生物污损的金属有机框架双网络聚电解质水凝胶吸附材料和抗污损型多孔网络结构聚丙烯酰胺基水凝胶材料。通过结构表征、模拟海水吸附实验和防污实验等系统地评价了水凝胶吸附材料对铀酰离子的吸附选择性能。项目通过引入平衡电荷聚电解质或防污活性物质赋予水凝胶材料抗污损性能，在实际应用中可抑制海水中污损生物细菌、海藻等的黏附，提高吸附剂表面活性位点的利用率。所制备的抗污损型水凝胶吸附剂在接近海水pH下对铀酰离子均具有较高的吸附容量和吸附选择性。综合模拟海水和实海试验结果，抗污损型ZIF-67金属有机框架聚电解质水凝胶的性能最为优异，其优异的性能源于其独特的双网络结构，即带相反电荷的海藻酸钠和聚乙烯亚胺之间的静电相互作用的第一网络结构和N,N-亚甲基双丙烯酰胺交联的聚丙烯酰胺链的第二网络所交织形成的平衡电荷双网络聚电解质结构，其类似两性离子的表面即起到防污作用，又提供了丰富的吸附活性基团位点，使其具有较好的吸附选择性，为解决海水提铀研究所面临的海洋生物污损问题提供新思路。