Studies On The Preparation And Related Properties In Environmental Remediation Of Porous Materials@Metal-Organic Framework Membranes

Porous materials are materials with a three-dimensional network structure composed of interpenetrating or closed pores.Due to their strong mechanical properties and good permeability,porous materials are widely used in adsorption,separation,catalysis and other fields.Metal-organic frameworks（MOFs）are a new class of porous inorganic-organic coordination hybrids consists of inorganic metal ions/clusters and organic linkers,with high specific surface area,abundant spatial structure,high porosity and good hydrothermal stability.They are widely used in the field of environmental pollution remediation such as removal of harmful gases and sewage treatment.MOFs can be grown on substrates through a certain process.Significant progress has been made in the preparation of MOFs films according to various application requirements in the past few decades,but the development of more controllable,green and large-scale commercial synthesis methods has been remaind a challenge.In order to develop porous materials with environmental governance functions,a series of MOFs membranes were synthesized by the methods of surface functionalization modification and prefabricated crystal assembly.And we focused on their performance in environmental governance.Three types of porous material@MOFs membranes with excellent performance in particulate matter adsorption and oil-water separation were obtained,which provided an effective reference for the development of synthesis methods and functional applications of MOFs membranes.The main research contents are divided into the following four chapters:Chapter 1:The brief overview of MOFs materials and MOFs membranes are described.In addition,the current preparation methods and applications of MOFs membranes are summarized and compared.Chapter 2:In order to design porous MOFs membranes with low air resistance and oil-water separation properties,porous melamine formaldehyde foam（MF）was selected as the substrate.One-step synergistic modification of MF with dopamine/β-cyclodextrin promoted the heterogeneous nucleation and growth of ZIF-8 on substrates.Using melamine formaldehyde foam（MF）as the substrate and one-step synergistic modification with polydopamine/β-cyclodextrin,which introduce the uniform active site promotes the heterogeneous nucleation process of ZIF-8 growth on the surface.The morphology and chemical composition of the prepared ZIF-8 membrane were characterized,and we also explored its mechanical stability.Finally,a condition optimization experiment was carried out on the factors affecting the membrane quality,and a stable and continuous ZIF-8 membrane was prepared successfully on the MF substrate.Chapter 3:We assembled the PM filtration performance test instrument,and the filtration efficiency and pressure drop of materials were tested.Furthermore,the quality factor was calculated to evaluate the overall filtration performance.The experimental results confirmed that MF@PDA--β-@P@ZIF-8 membrane has the best filtration performance,and its filtering performance remains almost unchanged after repeated and long-time testing.In addition,the oil-water separation performance of the material was further studied.Due to the surface of MF was modificated,the MF@PDA--β-CD@ZIF-8 membrane can adsorb oil and organic solvents selectively,and it has good environmental applicability at the same time.Chapter 4:In order to expand the preparation strategy of porous material@MOFs membranes,we composited ZIF-8 and UIO-66-NH₂ on the inner and outer surfaces of MF pores by introducing the binder carboxymethyl cellulose（CMC）,respectively.In addition,the method of introducing CMC/MOFs into the substrate and the suitable substrate were discussed.The experimental study on PM filtration of this type of composite material showed that it also has good comprehensive filtration performance,and MF@CMC@MOFs is a potential filter material.