Zn/Cu单晶转换MOF材料的CO_(2)/CH_(4)分离性能研究  

Metal-organic frameworks:metathesis of zinc (Ⅱ) with copper (Ⅱ) for efficient CO_(2)/CH_(4) separation

作　　者：刘增欣 王依军 郝春莲 刘秀萍 LIU Zengxin;WANG Yijun;HAO Chunlian;LIU Xiuping(School of Materials Science and Engineering,Linyi University,Linyi 276000,Shandong,China;School of Materials Science and Engineering,China University of Petroleum,Qingdao 266580,Shandong,China)

机构地区：[1]临沂大学材料科学与工程学院,山东临沂276000 [2]中国石油大学材料科学与工程学院,山东青岛266580

出　　处：《化工学报》2021年第S01期546-553,共8页CIESC Journal

基　　金：国家自然科学基金项目(21776315);山东省自然科学基金项目(ZR2020QB032)。

摘　　要：CO_(2)的捕获和分离具有重要的工业和环境意义。采用溶剂热法,以羧基和路易斯碱位点功能修饰的配体和锌离子构筑了阴离子型金属有机框架材料{[Zn_(2)(N)·(DMF)_(3)·(CH_(3))_(2)NH_(2)]·(DMF)_(2)}n(NEM-7-Zn)。为了提高骨架的稳定性,通过金属离子置换工艺,将NEM-7-Zn转化为高稳定性的铜基框架材料NEM-7-Cu。采用EA、PXRD、TGA及比表面积分析等技术对多孔材料进行综合表征,并测定了NEM-7-Cu对二氧化碳、乙炔和甲烷单组分气体的吸附等温线。实验结果表明,NEM-7-Cu不仅具有较高的CO_(2)吸附性能(74 cm^(3)·g^(−1)),更表现出优异的CO_(2)/CH_(4)(11.5)和C_(2)H_(2)/CH_(4)(7.1)吸附选择性。通过巨正则Monte Carlo方法(GCMC)计算得到CO_(2)在NEM-7-Cu中的主要吸附位点为功能基团羧基与路易斯碱位点附近以及Cu的金属团簇附近。The adsorption and separation of CO_(2) are of great importance from both industrial and environmental points of view.A metal-organic framework{[Zn_(2)(N)·(DMF)_(3)·(CH_(3))2NH_(2)]·(DMF)_(2)}n(NEM-7-Zn)was synthesized by nitrogen sites and-COO−groups decorated ligand.In order to improve the stability,the metal center of NEM-7-Zn was converted from Zn to Cu through metal ion exchange,which resulted in a stable skeleton(NEM-7-Cu).The synthesized materials were characterized by analysis techniques including EA,PXRD,TGA and specific surface area analysis.Single-component adsorption isotherms for acetylene and carbon dioxide on NEM-7-Cu was determined.Gas adsorption test results show that,NEM-7-Cu possesses high CO_(2) uptake(74 cm^(3)·g^(−1))and selectivities for CO_(2)/CH_(4)(11.5)and C_(2)H_(2)/CH_(4)(7.1).Grand canonical Monte Carlo(GCMC)simulations revealed the strong CO_(2) adsorption sites exist near the CuⅡcluster sites,the uncoordinated-COO−groups and the Lewis basic nitrogen sites.

关 键 词：金属-有机框架材料 金属离子置换(Zn/Cu) CO_(2) CO_(2)/CH_(4) 

分 类 号：O611.4[理学—无机化学]