Preparation And Analytical Application Of Some Magnetic Surface Molecularly Imprinted Polymers

Surface molecularly imprinting technique is a new-type of preparation method for synthesizing surface molecularly imprinted polymer microspheres which have more uniform grain size, shallower pores and more surface binding sites to deduce the mass transfer resistance of the target molecules and to improve their adsorption and desorption rates. And magnetic molecularly imprinting polymers have also been widely used in the separation and analysis of the environmental polluents for their unique magnetic performance and excellent molecular recognition ability.In this thesis, three magnetic molecularly impringed polymers have been successfully prepared by employing bisphenol A or p-hydroxy benzoic acid as a template molecule respectively with surface impringing technique. Structures,morphologies and properties of the synthesized imprinted polymers are characterized by Fourier transform infrared（FT-IR）, scanning electron microscopy（SEM）, X-ray powder diffraction（XRD） and thermogravimetric analysis（TG） and their adsorption properties have also been studied in detail.This thsis consists of four chapters.Chapter 1: The concept and principle of the molecularly imprinting technique are described briefly and the development background, synthesis methods and analytical application of the imprinted polymers are introduced in detail.Chapter 2: Magnetic surface molecularly imprinted polymer composite materials MMIPs（BPA）, with specific recognition for bisphenol A（BPA）, are successfully synthesized by using bisphenol A（BPA） as template molecules, methacrylic acid（MAA） as monomers, ethyleneglycol dimethacrylate（EGDMA） as crosslinkers,2,2’-azobisisobutyronitrile（AIBN） as a initiators, and CH3 CN as a porogen,on the surface of the nanoparticles ATP@Fe₃O₄, as-prepared by coating attapulgite（ATP）with Fe₃O₄ obtained through a co-precipitation procedure. Their morphology and structure are characterized and the adsorption properties towards to BPA are studied in detail. The results show that the prepared MMINPs（BPA） have a good recognitation performance for the imprinting molecule BPA and can be easilycollected by an external magnetic field. The maximum adsorbing capacity of MMIPs（BPA） towards BPA is 2710 m g.g-1 and the adsorption procedure obeys the pseudo-second order kinetics equation and Langmuir isothermal adsorption model. At last, the synthesized MMIPs（BPA） are successfully applied in concentration,separation and analysis of BPA in real water samples.Chapter 3: Magnetic molecularly imprinted polymers for BPA with two different functional monomers BM-MMIPs（BPA） are synthesized using ATP@ Fe₃O₄ as the support matrix, BPA as the template molecules, methacrylic acid（AA） and acrylic amide（AM） as the functional monomers and their morphology, structure and properties are characterized detailedly. The experimental results indicate that the maximum adsorbing capacity of BM-MMIPs（BPA） towards BPA reaches 3013 mg.g-1much higher than for BPA structural analogues such as phenol and hydroquinone, and the adsorption processes could be described with pseudo-second order kinetics equation and Langmuir isothermal adsorption model. Based on the selective adsorption of the imprinting material, a new spectrophotometric analytical method for BPA in environmental water samples is developed with a recovery of 97.30 % ¹01.0% and RSD less than below 5.70%.Chapter 4: Magnetic molecularly imprinted nanospheres BM-MMIPs（PHBA）with specific recognitation for p-hydroxy benzoic acid（PHBA） are prepared using as-prepared ATP@Fe₃O₄ as the support matrix, PHBA as template molecules, MAA and AM as the functional monomers, and EGDMA as the cross-linking agent and characterized in detail. The imprinted materials show an excellent selective recognitation property towards PHBA and its maximum adsorption amount for PHBA reaches 2598mg.g-1. The adsorption behaviours follow pseudo-second order dynamic equation and Langmuir isothermal adsorption model. By means of extraction and separation of the imprinted materials, a sensitive spectrophotometric analytical method for PHBA in environmental water samples is established with a recovery of90.30%- 101.9% and RSD less than 7.70%.