Studies On Synthesis And Adsorption Properties For Organic Compounds Of Polymer Coated Silica Composite Materials

Polymer coated silica adsorption materials, with excellent performance of silica gel and polymer, and even some new properties, are a kind of organic-inorganic composite material. These materials have potential applications in material fields, especially in adsorption fields. Using molecular imprinting technique can obtain novel polymer-coated silica that has specificity adsorption for metal ions and organic compounds. This thesis has designed and prepared eight novel polymer-coated adsorption materials by means of surface polymerization and molecular imprinting on silica. These adsorption materials were systematically characterized by Scanning electron microscopy(SEM), infrared spectroscopy (FT-IR), porous analysis, and thermogravimetry analysis. And adsorption properties of these materials towards organic compounds were investigated.Using modified silica as core, 4-vinylpyridine as functional monomer,divinylbenzene as crosslinking agent, respectively, four novel polymer-coated silica materials, including polystyrene-coated silica (PS/SG), poly(p-nitrostyrene)-coated silica (PS-NO2/SG), poly(p-aminostyrene)-coated silica (PS-NH2/SG) and poly(4-vinylpyridine)-coated silica (PVP/SG), were synthesized by means of polymerization on the surface of silica. Some organic compouds, such as phenol and aniline, were chosen as representatives to investigate static saturated adsorption. The main research focuses on the adsorption properties of aniline. The experimental results showed that the adsorption of aniline prior to phenol for the four adsorption materials in the range of the experiment. The adsorption isotherms results showed that linear Freundlich isotherm models could be well interpret the adsorption of three adsorption materials, PS/SG, PS-NO2/SG, PVP/SG, for aniline. The kinetics data indicated that the adsorption process was governed by the film diffusion and the intraparticle diffusion and well followed pseudo-second-order rate model.Adsorption performance of PS/SG, PS-NO₂/SG, PS-NH₂/SG, PVP/SG to phenolic substances (including phenol, p-methyl phenol, p-nitrophenol) and amine compounds(including aniline, N - methyl aniline, p- nitroaniline) from aqueous solution and nonaqueous solutions(including anhydrous alcohol solution, benzene solution and cyclohexane solution) was investigated in order to analysis the reason of the differences among these adsorption materials. The adsoption towards N- methyl aniline of PS/SG in different temperature was studied. The kinetic adsorption results showed that the adsorption process of PS/SG for N-methyl aniline was well followed pseudo-second-order rate model. The adsorption isotherms results showed that Freundlich models could be well interpret the adsorption of PS/SG for N- methyl aniline. Thermodynamic analysis revealed that the adsorption behaviors of N- methyl aniline on PS/SG could be considered as spontaneous,exothermic sorption process, resulting in their higher adsorption capacities at lower temperature.Using vinyl modified silica as the core, divinylbenzene as crosslinking agent, 4-vinylpyridine as functional monomer, N- methyl aniline and methamphetamine as the template, respectively, molecularly imprinted polymers were synthesed by surface of molecular imprinting technique. The experiments results showed that molecularly imprinted polymers showed excellent adsorption performance to the template, especially methamphetamine molecular imprinted on surface of silica. Using it as solid-phase extraction materials, the methamphetamine can be extracted from the complex system, including ketamine, caffeine exist and methamphetamine, which provides novel supporter materials for extracting amphetamine-derived drugs.