Studies On The Preparation And Environmental Application Of Metal-Organic Frameworks And Their Composites

Metal-organic frameworks?MOFs?are a kind of organic-inorganic hybrid crystalline porous materials constructed by organic connecting units and inorganic units?metal ions or clusters?.Due to their variability of ordered network structure,designability,modifiability and large specific surface area,MOFs have exhibit great application value,especially in the field of environmental application.Since the 20th century,MOFs have made great progress in synthesis,crystal engineering,function and application.However,the development of green and simple synthesis strategy for functional oriented MOFs and their composites is still a hot spot in the field of MOFs materials.In order to develop MOFs and theirs composites with environmental application value via green and simple synthesize method,we designed and synthesized a series of functional MOFs and theirs composites by solvothermal method,post synthesis modification strategy or solid-phase hot pressing process and studied their application in the field of environment,providing a new idea for the functional design and processing of MOFs.The main research results are as follows:1.In order to design and synthesize MOF with special affinity for greenhouse gas CO2,a series of 3D porous MOFs?Ln-MOFs?with uncoordinated O atoms and rich-N pyrazole groups on the surface of their channels were constructed by one pyrazoyl-carboxyl bifunctional ligand and seven kind of lanthanide metal ions.Among them,Eu-MOF presents highly selective capture for CO2 over N2 and CH4.Grand Canonical Monte Carlo?GCMC?simulation analysis reveals that the uncoordinated O atoms and rich-N pyrazole rings play an important role in improving the affinity between Eu-MOF and CO₂,which provides a reference for the development of MOF with excellent CO2 selective adsorption.2.Based on the soft-hard acid-base principle,thiol-functional SH-MIL-68?In?material with good selective adsorption performance for Hg?II?was synthesized via the post-synthesis modification?PSM?method through fixing mercaptoacetic acid on the channel walls of NH₂-MIL-68?In?.The adsorption kinetics and adsorption isotherms studies reveal that SH-MIL-68?In?has a fast adsorption rate(rate constant k₂=1.25 g mg^-1 min^-1)and a large maximum adsorption capacity(q_max=450.36 mg g^-1)toward Hg?II?.In addition,XPS analysis shows that the rich-SH soft basic groups on the surface of the channels in SH-MIL-68?In?were the main reason for its excellent Hg?II?selective adsorption.3.Based on the stable indium based MFM-300?In?MOF,a series of functional PW12@MFM-300?In?materials were prepared through one novel in-situ solid-phase hot-pressing process with adjusting the content of H₃PW₁₂O₄₀(denoted as PW₁₂)in the raw materials.This work not only overcomes the question that the utilization of independent POMs in catalysis reactions was constrained by their low specific surface areas as solid catalysts or difficult regeneration as homogeneous catalysts,but also realizes the green and fast synthesis of POM@MOF composites.Catalytic experiments show that the PW₁₂@MFM-300?In?composites have excellent catalytic degradation activity for the harmful substance sulfamethazine?SMT?,and 4-PW₁₂@MFM-300?In?possesses the high removal efficiency of about 98%toward SMT within 2 h at room temperature as well as can be recycled multiple times for this catalytic process.The mechanism study shows that the successful loading of PW12 favor the spatial separation of electron-hole pairs,which is the main reason for the excellent catalytic activity of PW12@MFM-300?In?composites.4.In order to overcome the fragile inherent defects of crystalline powder MOF,a series of flexible MFM-300?In?@Textiles composites with anti-UV radiation properties were prepared through the green solid-phase in-situ hot-pressing process to coat MFM-300?In?onto the surface of Cotton,Polyester or Aramid,realizing the synthesis of MFM-300?In?@Textiles without large amount of organic solvent.Transmission and ultraviolet radiation blocking tests reveal that MFM-300?In?@Textiles possess excellent UV-blocking property with almost full UVR blocking in the wavelength range of 280?315 nm and little water vapor permeability,flexibility and robustness loss,providing a new idea for the processing and forming of MOF materials as well as the development of new functions.5.A series of MOFs@Textiles composites were prepared by coating MIL-53?AL?,ZIF-8 and UiO-66 onto the surface of cotton,polyester and aramid via solid-phase hot-pressing process,which extended the MOFs@Textiles composites system.Air filtration experiments reveal that the prepared MOFs@Textiles composites exhibit excellent particulate matter?PM?filtration ability and good recycling performance.Among the MOFs@Textiles composites,MIL-53?Al?@Aramid has the best removal efficiency?95.30%for PM2.5 and 96.11%for PM10?under harmful air quality conditions(average PM2.5 mass concentration>280?g m^-3 and PM₁₀>360?g m^-3).