可控合成纳米零价铁/铁基MOFs增强水中U(VI)还原-固定机理研究

Currently, chemical reduction technology based on zero-valent iron nanoparticles (NZVI) has been considered to be a promising pathway for the in situ remediation of U(VI) in water. However, reaction activity of the NZVI during the treatment is diminished over time owing to the inevitable particle aggregation. How to effectively solve the stability of NZVI is a great task in the field of pollution control. An important feature of iron-organic framework materials (MOFs(Fe)) is that their framework structure, pore environment and functionality can be finely controlled by the choice of organic building ligand and how they connected. It would be favorable to design MOFs(Fe) as a support to combine NZVI within pores and/or cavities owing to the tunable porosity and high surface areas of MOFs(Fe). Both the reactivity and stability of NZVI would be also enhanced in this way. It also studies the properties and influencing factor of the removal of U(VI) onto the composite in order to deeply understand not only the relationship between structure coulping effect and reactivity of the NZVI but also the interaction between microstructure and removal machenism. It is expect to develop a new kind of material and technique in the field of nuclear waste water treatment.

基于零价铁（ZVI）的化学还原技术是当前水环境中铀污染原位修复的有效途径，然而零价铁在反应过程中易发生团聚而降低甚至丧失反应活性。如何提高纳米零价铁颗粒的稳定性、延长纳米零价铁的使用时间是污染控制领域中的一个重要课题。铁−有机骨架（铁基MOFs）中特有的高密度不饱和金属铁和易功能化的有机配体使其具有高活性和稳定性，以铁基MOFs为载体，利用其高比表面积和可调孔道组装纳米零价铁，可控合成纳米零价铁/铁基MOFs复合材料。研究在环境相关条件下零价铁/铁基MOFs增强对水中U(VI)的还原固定。考察接触时间、介质pH对U(VI)还原动力学的影响。探明不同环境条件下U(VI)反应产物的微观结构，以及铁的价态、化合态和结合态等赋存形态变化规律，揭示纳米零价铁、有机配体和不饱和金属铁之间的协同作用机制，阐明还原固定铀的规律特点和反应机理。发展适用于含U(VI)废水治理的新材料和新技术。

本项目通过材料的设计、优化和合成，优化制备方法，制备基于零价铁(Fe0)复合材料(Fe-Ni/GO、NZVI/CS、ATGO-nZVI 、 S-nZVI@OS、 PVP-nZVI/Ni、Fe-Cu/MBC )。获得了上述材料去除水中U(VI)的优异性能。通过静态吸附实验，研究溶液环境条件下零价铁复合材料增强对水中U(VI)的还原固定。考察接触时间、介质pH对U(VI)还原动力学的影响。采用宏观静态吸附法和微观表征相结合的方法，研究复合材料去除目标污染物的性能和机理，揭示复合材料与目标污染物间的协同作用机制，阐明还原固定的规律特点和反应机理。期望藉此为研究新型高效铁基复合材料去除核素和其他重金属离子提供可靠的科学依据和理论基础。