| As a new family of porous materials, Metal-Organic Frameworks(MOFs) built from metal ions and polyfunctional organic ligands. They have been one of the fastest growing aspects in cross fields of energy, materials and life science, because of their intriguing topology structures and Potential applications as functional materials in gas adsorption and separation, catalytic activities, optoelectronic materials magnetism, and so on. However, the application development of MOFs is far away enough. In order to expand the application of this materials, composites based on MOFs and the template for MOFs derivatives were prepared. This paper focuses on the utilization of MOFs composites for the removal and solid-phase micro-extraction of organic pollutants. The main contents of this thesis are as follows:Chapter 1: The nature, synthesis methods, research status of MOFs and its composites were introduced. The nature, migration and dangers of phthalate esters were reviewed, and its detection and pretreatment methods.Chapter 2: Two kinds of metal organic frameworks were synthesized by hydrothermal method and room temperature method, the products were characterized by X-ray diffraction(XRD), fourier transform infrared spectrometer(FT-IR) to verify the feasibility of methods.The properties for products, such as crystal particle sizes, pore size, completeness of crystal grains, thermal stability and the specific surface areas, were characterized using thermo-gravimetric analyzer(TGA), optical microscope(OP) and N2 adsorption device. The results show that MOF-5 and MOF-199 can be successfully synthesized by the two different methods. However, their crystal particle sizes, completeness of crystal grains, thermal stability and the specific surface areas are different, the crystal particle sizes of MOFs materials synthesized by hydrothermal method are bigger than the one synthesized by room temperature method, moreover, the completeness of crystal grains and thermal stability of former are better than the latter. In summary, the properties of the MOFs materials synthesized by hydrothermal method are better than that of the MOFs materials synthesizedby room temperature method, but the experiment apparatus and reaction conditions of hydrothermal method are much higher than another one.Chapter 3: A novel core-shell-shell composites based on metal-organic frameworks were synthesized by a step-by-step growth mechanism. The properties for products, such as composition, thermostability, morphology, were characterized by XRD, TGA, FT-IR, TEM and SEM. Concentration of reactants, synthesis temperature and reaction time were investigated. Methylene blue adsorption experiment was used to measure the adsorption capability of composites towards dyes. The result shows that the composite material has a good effect in the adsorption of organic pollutants. The result can be explained with the following mechanisms:(1) adsorption onto a coordinatively unsaturated site,(2) adsorption via acid-base interaction,(3) adsorption via ? complex formation,(4) adsorption via hydrogen bonding,(5) adsorption via electrostatic interaction, and(6) adsorption based on the breathing properties of MOFs and so on.Chapter 4: The synthesized composites were used as solid-phase micro-extraction agent and combined with gas chromatography(GC) and flame ionization detector(FID).The application was devoted to the determination of 6 phthalate esters(PAEs) in green tea samples.In order to get the higher extraction ratio, the extraction conditions were investigated in detail,such as pH of the solution, elution solvent, amount of microspheres and extraction time. The average recoveries were obtained in the range of 72.9%~89.2% with precision 1.9%~5.1%.The limits of detection and quantitation of the proposed method were in the range of 2.1-7.4?g L-1 and 8.2-23.2 ?g L-1, respectively. This method can be used for the determination and monitoring of PAEs in food samples fast and effectively. |
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