多孔MOFs材料除Hg0的构效关系研究与分子剪裁

The capture and removal of heavy metal element mercury (Hg0), especially for the removal of Hg0 from gas pollution, is always a great challenge for scientific and technological workers. The metal organic frameworks (MOFs) are a kind of ideal materials for removal of Hg0 because they have the advantage of large specific surface area, extremely large surface to volume ratio and tremendous structural flexibility. Considering the chemical property of elemental mercury, a series of new functional ligands containing sulfydryl, alkynyl and multiple carboxyl groups will be synthesized. A series of MOFs compounds will be constructed by coordination of metal and the above ligands. Then, the compounds will be characterized and activated and the Hg0 removal will be studied with MOFs materials. Based on analyzation of the molecular structure of MOFs, the factors such as the topology of the compounds, specific functional groups and the metal of the node et al. affecting the efficiency of Hg0 removal will be studied by the combination of simulated calculation and experimental characterization. Thus, the mechanism of Hg0 removal will be clarified. The key factor and the rule affecting the Hg0 removal will be found and which will provide us the guidance to complete the controlled syntheses of MOFs materials with Hg0 removal. The hydrophobic MOFs materials will be built through the coordination of “hard metal” and the ligands containing carboxyl group. The reason of their hydrophobic property will be calculated and analyzed. Thus, the higher adsorptive MOFs materials for Hg0 removal are expected. And this work lays a foundation for the real application of MOFs materials.

捕获、去除重金属元素汞（Hg0），特别是气型污染物中的Hg0，一直是科技工作者面临的难题。有机金属骨架（MOFs）材料因具有比表面积大、孔隙率高、结构多样等独特优势，成为一种理想的除Hg0材料。本项目结合单质汞的化学性质，拟合成含巯基、炔基等功能团修饰的系列新型多羧酸配体，以此与金属离子配位构筑得到多个多孔MOFs化合物，完成相关的表征与活化；对MOFs材料进行除Hg0研究，在确定MOFs分子结构的基础上，采用模拟计算与实验表征相结合的手段，研究MOFs的拓扑结构、特定功能团、节点处金属离子等对Hg0的吸附去除效果的影响，明确Hg0的吸附去除机理，找出影响汞去除的关键因素和作用规律，指导我们完成对MOFs除Hg0材料的定向设计；通过“硬金属”与羧酸配体配位，得到疏水性MOFs材料，计算分析MOFs耐水性的原因，以期合成出更加高效的疏水性MOFs除Hg0材料，为其大规模应用奠定基础。

重金属离子可长期累积在人体内，对环境和人体健康构成了严重威胁。其中，重金属汞存在多种形式（Hg0、Hg+/Hg2+、Hgp），因而对其治理备受关注。本课题主要采用MOFs材料针对汞的捕获进行了研究。首先，设计合成了含有炔基、咪唑阳离子、氨基、含S基团等各种功能团的MOFs材料，对其结构、性能进行了表征分析；对含有炔基、咪唑阳离子等MOFs材料进行了Hg0的捕获研究，但结果并不理想，主要原因是测试过程中MOFs晶体粉末会聚集于容器壁上，减少了Hg0与MOFs材料的接触面积，因此，后期我们主要对Hg2+的识别、吸附、重现性等进行了研究；结果表明，含有氨基等功能团的MOFs材料中，其未配位的氮原子能够与Hg2+产生相互作用，从而有效地识别Hg2+，识别Hg2+后的MOFs材料通过简单水洗仍可重复使用。本研究为功能性MOFs材料的剪裁提供了参考依据，为废水中金属离子的去除提供了一条新的途径。