Preparation And Properties Of Metal-Organic Framework Materials And Membranes

Metal organic frameworks?MOFs?are a kind of porous crystalline material,which are composed of inorganic metal centers and organic ligands.It has the properties of both inorganic and organic materials.As a kind of new material,MOFs have wide application prospects in the fields of water treatment,catalysis,batteries,sensors,gas storage,separation,etc.MOFs material has advantages of enormous surface areas,ultrahigh porosity,excellent thermal stability,chemical stability and easy to realize functionalization,so they have attracted extensive attention of researchers in the fields of materials science,chemistry,chemical engineering and so on.Due to the advantages of MOFs crystals,MOF membranes have become a promising material,which attract more and more attention from researchers all over the world.MOF membranes exhibit excellent performance in gas and liquid separation,and can also be used in catalytic and sensing devices.In this paper,the application of MOF membrane in the field of oil-water separation and a dynamic metal organic framework material and preparation of its film are studied.Owing to the discharge of oily wastewater from petroleum,steel and textile industries and frequent oil spills,oil pollution has become an important global environmental and economic problem.The research of high efficiency oil-water separation material and technology has important scientific significance.Traditional oil-water separation methods including centrifugation,adsorption,flotation,etc.,which have high energy consumption,large area occupation,time-consuming process and low separation efficiency.In recent years,membrane separation technology has been developing continuously,which has the advantages of simple separation equipment and low energy consumption.It is an effective technology to treat oily wastewater.As known,ZIF-8 crystal has good chemical and thermal stability,cheap raw materials and simple synthesis method.We successfully prepared ZIF-8 oil-water separation membrane using stainless steel mesh as support at room temperature and atmospheric pressure.This membrane exhibits underwater superoleophobic properties,which can separate different oil/water mixtures underwater driven by gravity,showing high oil/water separation efficiency over 99.99%.It exhibits a water flux as high as10.2×10⁴ L m^-2 h^-1 and higher oil intrusion pressure.In addition,the membrane also exhibits excellent stability towards high temperature and organic solvents immersion.Furthermore,Because of the simple preparation method,the membrane can realize large-scale production.Rigid metal organic frameworks materials have always been a research hotspot.In recent years,scientists are increasingly interested in dynamic metal organic frameworks materials.Its frameworks structure and properties can be changed under different external conditions,such as temperature,light,pH,magnetic field,guest molecules and so on.We synthesized a dynamic three-dimensional MOF?[Cu₂?bdc?₂?bpy?]_n?with interpenetrating structure by a simple and time-saving method,and studied its performance.The framework structure of the MOF is reversible.Furthermore,[Cu₂?bdc?₂?bpy?]_n film was prepared on alumina substrates by seed-assisted secondary growth method,which laid a foundation for the preparation of dynamic controllable separation membrane.