高效、稳定型π络合吸附材料的制备及其乙烯/乙烷分离性能研究

With the characteristic of low consumption, π complexative adsorption is considered as one of the most promising alternative methods to cryogenic distillation. In order to solve the problems of less adsorption capacity, low selectivity and lack of stability, this project aims to prepare a group of π complexative adsorbents with high effect and stability. The concrete features of adsorbents contain high specific surface area, strong complexative bond energy and property of redox inert. New porous materials MOFs are selected to be the support, so that the demand of high specific area is realized. Modification with active metal ion Cu(I) could satisfy the requirement of strong complexative bond energy. By use of the character that the valence states of center ions in several MOFs are alterable, the property of redox inert is achieved, meanwhile mechanism of action is probed. Both solvent free and double solvent techniques are used to incorporate active species Cu(I) into the support MOFs, and excellent preparation systerm should be constructed. The adsorbents will be characterized of component, valence state and structural property with scientific and modern analytical techniques (such as XRD, XPS etc.). The performance of adsorbents on ethylene/ethane gas separation will be investigated in the way of experimental study and theoretical calculation. The inherent relationship between the adsorbent parameters and the separation performance is clarified, and the structure-activity relationship is established. This project may provide a new route for design and preparation of theπcomplexative adsorbents.

π络合吸附技术具有低能耗的特点，被称为最有前景取代低温精馏的方法之一。针对吸附材料吸附容量小、选择性低、稳定性差的问题，本项目拟开发一类高效、稳定的π络合吸附材料。具体表现为，吸附材料兼具高比表面积、强络合键能、氧化还原惰性的特色。将新型孔材料MOFs作为吸附材料的载体，实现高比表面积；采用活性金属离子Cu(I)修饰，实现强络合键能；借助几种MOFs骨架的中心离子具有价态可变的性质，实现氧化还原惰性，同时探索可能的作用机制。拟采用无溶剂、双溶剂的方法将活性金属组分Cu(I)引入载体MOFs，构建完善的制备体系。采用科学的现代分析技术（XRD、XPS等）对吸附材料的组成、价态、结构进行研究；以实验研究和理论计算相结合的方式，探讨吸附材料分离乙烯、乙烷气体的性能。阐明吸附材料的表面性质、结构参数与其分离性能之间的内在联系，建立构效关系。项目的实施为π络合吸附材料的设计和制备提供新的思路。

低温精馏是目前化学工业中分离相似结构气体分子的有效手段，但其需要巨大的能耗。π络合吸附分离技术可以在温和的条件下实现气体分离，具备低能耗的特点，有望取代低温精馏。然而，π络合吸附材料仍然面临吸附容量少、选择性低和稳定性差的科学问题。基于此，本项目开发出兼具高性能和强稳定性的π络合吸附材料。采用金属有机骨架材料HKUST-1和MIL-101为载体，实现超高比表面积；从固相研磨法到双溶剂法，实现π络合吸附位点的位置调控，提高其分散性，且实现Ag(I)位点的强稳定性；采用引入变价态金属元素V和Co的方案，实现Cu(I)位点的构筑和强稳定性。最终，制备出π络合吸附材料CuHT、AgM-DS、CuVM和CuCoM-DS等，不仅在π络合吸附分离C2H4/C2H6应用中展现出高性能，且在CO、H2和N2混合气分离中同样展现显著的效果，包括高吸附容量和高选择性。依据表征测试和性能结果综合分析，得出如下结论：MOFs的多孔性质和超高比表面积使其非常适宜作为π络合吸附材料的载体；金属活性位点在MOFs的孔道内部有利于其高分散，从而有利于实现高吸附分离性能；Ag(I)在MOFs孔道内部有利于其减缓光照分解过程，从而稳定性得到提高；V或Co的引入有利于Cu(II)还原为Cu(I)，并使Cu(I)稳定性更强。此外，在完成研究任务的基础上，上述相关制备理论还拓展应用到催化材料的制备过程中，得到QS-CoS和SAFe-SBA，其在高级氧化水处理过程中展现高活性。