Preparation Of Supported Metal-Organic Framework Of MIL-100(Fe) And Its Visible Light Catalytic Performance

Metal-organic frameworks（MOFs）is a kind of porous materials synthesized by self-assembly of metal ions and organic linkers.Due to the characteristics of large specific surface area,high porosity and tunable structure,MOFs have been widely used in catalysts adsorption,storage and other fields.MIL-100（Fe）is a kind of iron-based metal organic frameworks,which is one of the most potential materials in MOFs due to its advantages such as simple preparation,low cost,non-toxicity and so on.However,single MIL-100（Fe）catalyst often needs to be recovered by complex high-speed centrifugation,so it is easy to cause secondary pollution.Therefore,this thesis focuses on the preparation of supported MIL-100（Fe）photocatalysts,aiming to prepare the catalyst high catalytic performance,high stability and easy to recyle.The specific research contents and results are as follows（1）ESM@MIL-100（Fe）composite catalyst was prepared by layer-by-layer self-assembly method using Egg shell membrance（ESM）as carier.The characterization results show that MIL-100（Fe）can be evenly loaded onto the surface of ESM,and its loading amount can be adjusted by the number of assembly cycles.The self-assembly process at low temperatures does not cause obvious damage to the structure of the ESM.In the presence of H2O₂,the photocatalysis efficiency of the ESM@MIL-100（Fe）composite fiber membrane assembled 10,20 and 30 times under visible light for 1 h was above 98%for Rhodamine B（RhB）solution.Using ESM as a carrier not only makes the deposition of MIL-100（Fe）easy to operate,but also makes ESM@MIL-100（Fe）composite catalyst easy to recycle（2）Flexible SiO₂@MIL-100（Fe）composite fiber membrane with core-shell structure was prepared by layer-by-layer self-assembly method using flexible SiO₂ fiber membrane as carrier.The results show that the core-shell composite fiber structure was formed by loading the prepared SiO₂@MIL-100（Fe）composite catalyst exhibited high photocatalytic degradation activity for Rhodamine B（RhB）solution.After three catalytic cycles,the catalytic efficiency of the composite catalyst was over 80%in 90 minutes.（3）Fe₃O₄@MIL-100（Fe）composites were prepared by layer-by-layer self-assembly method and one-step hydrothermal method using magnetic Fe3O4 nanoparticles as carriers.By controlling the number of cycles of self-assembly and the addition of organic ligand（H3BTC）in hydrothermal method,the morphology and photocatalytic properties of Fe3O4@MIL-100（Fe）composites were regulated.The results indicate that the catalysts are with uniform size and good thermal stability,and the degradation ability of Rhodamine B（RhB）solution is better.Among them,Fe3O4@MIL-100（Fe）prepared by self-assembly for 15 times showed better photocatalytic activity than that prepared by hydrothermal method because it is loaded more MIL-100（Fe）.Importantly,the strong magnetic response and stability of Fe3O4 make Fe3O4@MIL-100（Fe）have the characteristics of fast separation and recovery.