Preparation And Characterization Of Bisphenol A Molecularly Imprinted Mesporous Organosilica

Molecularly imprinted polymers having high selectivity, good stability, strong anti-harsh environment and other characteristics, were widely used in separation and analysis, solid phase extraction, sensors, drug testing and other fields. Binding sites and imprinting cavities of the molecularly imprinted polymers are embedded deep in the general mehod, showing a slow kinetic. Mesoporous silicas have large specific surface area and a high void volume, good thermal stability, functionality, narrow pore size, so they are very suitable for imprinting matrix. The new material can solve some shortcomings of traditional molecular impringting method.In the paper,the synthesis mthods and the applications of molecularly imprinted polymers were summarized, including the advantages and disadvantages of the methods. The development of the silicon imprinting matrix and synthesis methods of mesoporous MCM-41 and SBA-15 were introduced as well as the characterization and application of the mosoporous silica. Then the basis, significance of dissertation, and contents of this research were presented.Two different mesoporous silica MCM-41 and SBA-15 were prepared by optimizing the synthesis conditions. The MCM-41 was prepared under weak alkaline condition by sol-gel method using hexadecyl trimethyl ammonium bromide as the surfactant and TEOS as the silicon source. SBA-15 was prepared under acicic concition by sol-gel method using P123 tri-block copolymer as template and TEOS as the silicon source. Template agents were removed by high temperature cacination method. Mesoporous materials were characterized by infrared spectroscopy, X-ray diffraction, SEM for confirming the success of the material preparation. The aminopropyltriethoxysilane was grafted to the mesoporous surface of MCM-41 and SBA-15 to form the template molecules combining sites. They combinded with the template molecules to prepare bisphenol A molecularly imprinted mesporous organosilica.Two different imprinted materials were measured by adorption kinetics, adsorption isotherm, adsorption selectivity, cyclic adsorption experiment.The impinted mesoprous silica MCM-41 showed a high kinetics for the template biphenol A, reaching equilibrium within 50 min and the selective adsorption experiments showed that adsorption quantity of MIP is much larger than that of NIP. The template molecule has specific binding properties when analogue exsiting in the competitive system. Cyclic adsorption experiment showed recyclability. The adsorption equilibrium of SBA-15 molecularly imprinting material is within 20 min, and it has been greatly improved compared to traditional molecular imprinting polymers. The adsorption selectivity experiment showed high selectivity to the biphenol A. The material maintained a good recyclability after four times elution- adsorption – elution. SBA-15 molecularly imprinted material has potential value on the application of practical sample.Adsorption kinetics and adsorption quantity of two different molecularly imprinted mesoporous organosilica were contrasted. Adsorption rate and adsorption quantity of SBA-15-MIPs better than that of the MCM-41-MIP, and the recycling rate was slightly lower than that of MCM-41-MIP. This has a great pore structure associated with its own base. It has great correction with different pore structure.Using the SBA- 15- MIP for recovery experiment in water samples, the recovery in the range from 92.8% to 99 %, showing that SBA-15-MIP enrichment of bisphenol A is effective, it can be used in practical sample. The adsorption equilibrium of SBA-15 molecularly imprinting material is within 20 min, faster adsorption rate and higher adsorption quantity make SBA-15-MIP has a practical value.