我国是煤炭生产大国，每年由于采煤排放出大量的低浓煤层气（抽放煤层气），CH4含量低以及大量N2的存在是制约抽放煤层气直接利用的主要因素。因此，经济高效地分离CH4/N2是亟需解决的重点问题。目前，低温除氮技术存在能耗高的缺陷，变压吸附技术依赖于新型高效吸附剂的研制。沸石咪唑酯骨架（ZIFs）材料是一种具有沸石结构的新型金属有机骨架材料，结构中咪唑环上取代基团类型和位置的变化能够有效调节和提高ZIFs材料的极性，存在高效选择吸附CH4的可能性。本项目计划优选咪唑衍生物配体设计合成ZIFs材料，通过咪唑环上引入拉电子基团或不对称取代基团来提升ZIFs材料的孔道极性，进而提高CH4的吸附选择性，实现低浓煤层气中CH4/N2的高效分离。通过性能-结构/组成-合成之间的规律研究，获得CH4/N2吸附分离性能优良的ZIFs材料，为工业应用提供理论基础。

China is a major coal producer. A great amount of low concentration coalbed methane (coalbed gas extract) is released during coal mining every year. The low content of CH4 and the existence of large amount of N2 restrict the direct use of the low concentration coalbed methane. Thus, the separation of nitrogen and methane economically and efficiently has become an urgent problem to be solved. At present, cryogenic distillation technique for the separation of nitrogen has some defects, especially high energy consumption, and the pressure swing adsorption technique depends on the development of new adsorbents. Zeolitic imidazolate frameworks (ZIFs) is a new subclass of metal-organic frameworks with zeolite-like structure. The changes of the types and positions of substituted groups can efficiently adjust and improve the polarity of ZIFs, which may lead to highly selective adsorption of CH4. This project plans to design and synthesize ZIFs by using the selection of imidazole derivatives. The introduction of electron-withdrawing groups or asymmetric substituted groups on the imidazole ring can improve the channel polarity of ZIFs so that the selective adsorption of CH4 can be lifted, which will support efficient methane/nitrogen separation in the low concentrated coalbed methane. By the research on the rules of peformance, structure/composition and synthesis, highly efficient ZIF adsorbents for the adsorption and separation of CH4/N2 will be obtained, which will provide theoretical basis for industrial application.