Study On Preparation, Adsorption Performance And Application Of Phthalic Acid Dibutyl Molecularly Imprinted Polymer

Phthalic acid esters are the most widely-used plasticizer in plastic industry and easily affected by external environment factors to release into the environment, which is harmful to human environment and health. Phthalic acid ester also influent biological reproductive system and the endocrine system, because it is considered to be endocrine disruptors. And its easy migration and enrichment in organism is likely to cause deformity, cancer and gene mutations in the biological body.Therefore, effective separation/analysis phthalic acid esters of environmental samples have important practical significance.Molecular imprinting technology is a state-of-theart technique which has become a powerful method for the preparation of selective materials that have the ability to recognize a specific chemical material. Combined molecular imprinting technique, solid phase extraction, and chromatographic analysis method, it can be very perfect to improve the current problems of the detection methods for phthalate esters in the present.In this study, the high performance molecularly imprinted polymers is synthesized through three different polymerization methods by using methacrylic acid(MAA) as the functional monomer, ethylene glycol dimethacrylate(EGDMA) as the cross-linker agent, and azoisobutyronitrile(AIBN) as the initiator, which have the specific adsorption performance for DBP. This study mainly included the following items:(1) Novel ionic liquid-mediated molecularly imprinted polymers(ILMIPs) were developed in this study by situ thermal polymerization method using the ionic liquids 1-butyl-3-methylimidazolium hexafluorophosphate(BMIM+BF4) as an excellent auxiliary porogen. The polymer was characterized by scanning electron microscopy and Fourier transform infrared spectrometry. Adsorption dynamics models and the adsorption isotherm models were carried out to analyze its adsorption performance. Using the prepared ILMIPs as a solid phase extraction sorbent, which indicated that ILMIPs-SPE had a higher enrichment efficiency and a better selectivity for DBP, and the average recoveries of DBP at four spiked levels were in a range of 96.4-101.3%(n=5) with RSD ≤6.9%.(2)The silicon dioxide, as the support, was modified to introduce the polymerizable double bonds and terminal carboxyl groups simultaneously. And then, the molecularly imprinted polymers(Si O2-COOH-MIPs) was prepared through surface imprinting technology and the low monomer concentrations were used in the imprinting process.Scanning electron microscopy, transmission electron microscope, elemental analysis and fourier transform infrared spectrometry was employed to characterize the surface molecularly imprinted polymers. And Si O2-COOH-MIPs were evaluated by adsorption isotherms/kinetics, selectivity adsorption and desorption and regeneration experiments. These results showed that the Si O2-COOH-MIPs had a short equilibrium time(60 min) and high stability(retained 88% after six cycles). Furthermore, the Si O2-COOH-MIPs were applied to detect dibutyl phthalate from tap water samples, this method was accurate and simple, which had a low limit of detection(5.2 μg/L) and showed a high recovery with RSD % values of 6.9- 8.3%.(3)The Fe3O4 magnetic nanoparticles were coated with silica layer(Fe3O4@Si O2), and then functionalized by surface graft copolymerization for introducing the polymerizable double bonds and terminal carboxyl groups. Next, a magnetic surface molecularly imprinted polymers(MSMIPs) were developed to imprint DBP on the surface of carboxyl-modified silica nanoparticles by surface imprinting technique. Scanning electron microscopy, Transmission electron microscope, Vibrating Sample Magnetometer, Elemental analysis and Fourier transform infrared spectrometry was employed to characterize the magnetic surface molecularly imprinted polymers. The adsorption process obeyed pseudo-second-order model by kinetics analysis, Sips equations were suitable to experimental data by isotherm analysis. Selectivity and reproducibility experiments showed that MSMIPs for DBP has strong selectivity and the recycling effect was better.