Study On Preparation Of Flavone Imprinted Silica Microspheres And Its Molecular Recognition Mechanism

Till now, many adsorbents have been used to solve separation problems in many fields such as purification, separation, analysis and so on. But the problem of low adsorption selectivity still exists. While molecular imprinting technique is becoming increasingly recognized as a powerful technique of preparing synthetic polymers that contain tailor-made recognition sites for certain molecules. So it has been given a great attention from all sides in recent years and gained a great progress till now. But the problems of imprinting and recognition difficulty in aqueous phase, low mechanical strength and durability of the product have not been solved completely.In order to solve these problems, sol-gel method, molecular imprinting technique and suspension polymerization method were employed to prepare a new kind of molecularly imprinted silica adsorbent with good spherical appearance. In this thesis, using luteolin as template molecule, aminopropyltriethoxysilane as functional monomer, tetraethoxysilane as cross linking agent, the molecularly imprinted silica microspheres were prepared. SEM, granulometer, FTIR, elemental analysis were employed to assay to product. The conditions of adsorption and desorption were reviewed using static adsorption method, and imprinting and recognition mechanism was also studied.Research of the preparation process shows that molecularly imprinted silica microspheres with 20~30μm diameter can be prepared in aqueous phase by this method. Factors which influence the sphericity and particle size had been examined. The results of elemental analysis and FTIR indicate that there are recognition groups in the microspheres after imprinting. The result of static adsorption and desorption experiment shows that this adsorbent has a high saturation adsorption capacity and high selectivity, high adsorption-desorption rate and reproductivity.The result also shows that this molecularly imprinted silica microspheres prepared in this thesis adsorb the template in the way of Langmuir. And there is a decrease of enthalpy during the adsorption process. What's more, these microspheres also have high partition coefficient to template molecule.