The Preparation And Separation Performance Of Metal Organic Framework Porous Membrane

The field of metal-organic frameworks (MOF) has been growing tremendously over thelast15years. Metal-organic framework (MOF) materials are constructed from metal ions ormetal ion clusters and bridging organic linkers, which exhibit regular crystalline lattices withrelatively well-defined pore structures and interesting properties. As a new class of porous solidmaterials, MOF are attractive for a variety of industrial applications including membrane forseparations, which is a rapidly developing research area. Many reports discussed the synthesisand applications of MOF but relatively few reports about MOF membranes. Membranes madefrom specific MOFs are expected to offer unique opportunities with a potential to achievesuperior performance, which not only extends the application of MOFs, but may also provide asolution for many engineering challenges. The ability to rationally tune the structure of thematerials may create unique interactions with guest molecules and thus achieve unusualchemicophysical properties in separation or catalysis.In the first part of this article，it provides an over view of the diverse MOF membranesprepared up to now and starts with a brief introduction to the current techniques for thefabrication of MOF membranes, and followed by some classic examples of gas and liquidseparation applications with different MOF membranes.In the second part of this article, it introduces a new mixed-ligand Zeolitic ImidazolateFramework Zn4(2-mbIm)3(bIm)5·4H2O (named as JUC-160,2-mbIm=2-methylbenzimidazole,bIm=benzimidazole, JUC=Jilin University China) membrane. It has been synthesized by theassembly of Zn(NO3)·6H2O, bIm and2-mbIm under the solvothermal condition in DMFsolution at180℃. It was preparation on a porous ZnO slice and facilely synthesized using an insitu growth method. The topological analysis indicated the JUC-160has zeolite GIS(gismondine) topology. Studies of thermal and chemical stability show that JUC-160membranehas high thermal stability, and remarkable chemical resistance stability in boiling alkaline waterand organic solvent up to one week. The single gas permeantion experiment is carried out andshows that JUC-160membrane also exhibits high permeance of H2and low permeance of CO2.The ideal selectivity shows that JUC-160could be used for the H2or CO2separation of the application.Hydrogen-based energy system could address issues related to global climate change,energy security, and local air pollution. Chemically and hydrothermally stable microporousmembranes with intrinsic high H2/CO2selectivity are highly demanded. In the third part, anovel zeolitic midazolate framework (ZIF-7) membrane was introduced for its uniquepreparation method and high ideal selectivity of H2/CO2. It was prepared on a porous ZnO sliceand facilely synthesized using an in situ growth method. ZIFs are microporous materials andbelong to the new class of metal–organic frameworks (MOFs). ZIF-7is formed by bridgingbenzimidazolate anions and zinc cations resulting in a sodalite (SOD) topology with a pore sizeof about0.3nm. The ZIF-7membrane exhibited promising H2separation abilities. At220℃,The permeation of H2through the ZIF-7membrane is high. The ideal selectivity shows it couldbe used for the H2separation of the application. Due to the ultra-hydrophobic properties of ZIFmaterials, the ZIF-7membrane also showed the excellent hydrothermal stability in the presenceof steam. Our results clearly demonstrate that ZIF-7membranes have an intrinsic high H2/CO2selectivity and a promising application in hydrogen separation, which is based on its verynarrow and well-defined crystal pore structure.Membrane separation offers great promise owing to incomparable preponderance overtraditional methods with advantages such as low-energy consumption, large processing capacity,and a continuous mode of operation. Nowadays considerable attention is being paid to chiralresolution on account of significant differences in biological and pharmacological properties ofthe isomers of chiral compounds. One has the desired affect while the other may be inert oreven harmful. In the end of this article, I introduced a homochiral MOF membrane. Themembrane was successfully and facilely synthesized using an in situ growth method, which hadthe advantages of cheap raw materials, simple operation and high thermal stability. Afteractivation treatment, the membrane has a clean chiral pore. The application of the value of themembrane of chiral resolution is well worth to continue to study.