Synthesis Of Magnetic Zr-based Porous Coordination Polymer For Removal Of Environmental Pollutant

Polycyclic Aromatic Hydrocarbons（PAHs） are one of the persistent organic pollutants（pops） which is of cancerigenic, teratogenic and mutagenic capabilities. PAHs are stable and can exist in the atmosphere, water and soils for a long time. At present, 16 of PAHs have been designated as detection items firstly by Environment Protection of American（EPA）. Because of the low concentration of PAHs in the environment, sample pretreatment is essential to analysis them accurately. In recent years, in environmental sample pretreatment technology, magnetic adsorption materials can not only enrich and separate fast in environmental medium, but also avoid the high back pressure, column blockage, more adsorbents caused by conventional packed column. Magnetic solid-phase extraction combines traditional solid-phase extraction technology and the advantages of modern magnetic nanomaterials, which showed a significant advantage at the consumption, operation complexity and the extraction efficiency compared with other traditional enrichment technology. Porous coordination polymer（PCP） is a new type of porous crystalline materials which have been prepared by self-assembly of oxygen or nitrogen-containing rigid organic ligands and inorganic metal ion clusters. The uniform controllable channel, easy to functional modification, larger specific surface area and good solvent stability make them as potential adsorption material to analysis water pollution. This dissertation focuses on the utilization of PCP for the removal and magnetic solid-phase extraction of organic pollutants- naphthalene, pyrene, fluorine, phenanthrene and fluoranthene. The main contents of this thesis are as follows:1. The uniform size, good dispersion, nearly spherical sphere magnetic microspheres were prepared by the solvent thermal reduction process. The diameter of spherical dramatically increases from 250 to 700 nm, and preliminarily explores the influence of PEG molecular weight, ferric chloride addition amount, reaction time on the morphological structure. The experimental results show that with the increase of ferric chloride concentration and reaction time. Meanwhile, PEG with different molecular weight was investigated. There was no apparent effect from varying molecular weight.2. UiO-66 is a Zr-based porous coordination polymer, which is formed by self-assemble of ZrC l4 and terephthalic acid. It has excellent water resistance, acid resistance, larger specific surface area, which make it a high-performance adsorbent materials. So we use a simple and effective strategy, controlling coating numbers make UiO-66 coated on Fe₃O₄ surface, synthesis of a series of different size of Fe₃O₄@UiO-66 magnetic core-shell microspheres, realized its size control. The relative SEM and TEM images clearly show that magnetite particles are individually coated with a uniform UiO-66 shell, and the shell thickness could be easily tuned by varying layer number coated on the magnetic core. Further, other series of characterization also proved that UiO-66 coated on the surface of Fe₃O₄ successfully and keep their stable structure, regular sphere, good dispersion and superior magnetic properties, which easy to magnetic solid phase extraction.3. The Fe₃O₄@UiO-66 synthesized was applied to magnetic solid-phase extraction, combining gas chromatography analyze five kinds of trace PAHs-naphthalene, pyrene, fluorine, phenanthrene and fluoranthene in evironmental water and studied the extraction time, ionic strength, the absorbent quality, p H, humic acid and solvent elution on the influence of adsorption performance to PAHs. The experimental results show that the material has superior extraction efficiency to PAHs.