Synthesis And Enrichment Properties Of Magnetic Polystyrene Multifunctional Materials

Magnetic dispersive solid-phase(MDSE)extraction based on magnetic materials has been widely concerned in the technique of sample pretreatment.The extraction phase of MDSE and the analyte can be well mixed and evenly dispersed in the sample in comparison with the traditional solid phase extraction.The mass transfer and diffusion of the analyte between the extraction material have been not limited by the shape of the extraction stationary phase.The extraction equilibrium of MDSE would be reached faster and its extraction efficiency would be greatly increased.The polystyrene material issuitable to be the extraction medium because of their good rigidity,acid-alkaline resistance and functional modification.In this thesis,the research work isfocused on the preparation and evaluation of various magnetic polystyrene functional materials which can be used to concentrate different analytes such as polycyclic aromatic hydrocarbons and harmful metal ions.The designs of magnetic polystyrene functional materials aim to improve the selectivity and extraction efficiency of the proposed material.On the other hand,the magnetic polystyrenepolydopamine composite material has been prepared and possessed the effective molecular recognition ability according to easy coating and multi-reactive group of the polydopamine(PDA)material.The enrichment properties and mechanism of these proposed magnetic polystyrene functional materials hasalso discussed in order to provide some theoretical information for subsequent application.Paper main research contents and results are divided into three parts as follows:1.The magnetic polystyrene-vinylbenzyl chloride material was prepared successfully by using azodiisobutyronitrile(AIBN)as the initiator,vinylbenzyl chloride(VBC)as the monomer,the mixture of toluene and PEG2000(m/m=1/2)as the porogen and divinyl benzene(DVB)as the cross-linker.Fourier infrared spectrum(FT-IR),X-ray diffraction(XRD)and nitrogen adsorption measurement(BET)have been used to characterize the structure and form of magnetic polystyrene-chlorine methyl styrene material.The preparation and enrichment of the proposed material have been investigated by using anthracene as the target analyte.The optimum preparation condition was as follows: the mass ratio of VBC to DVB was 1:4;the mass ratio of VBC to the porogen was 1:1.The results showed that the enrichment mechanism of the prepared material was mainly based on the hydrophobic interaction.It was found that the prepared material could not concentrate some small aromatic compounds such as benzene,toluene and naphthalene.The maximum adsorption efficiency of the prepared material on paranaphthalene was 97%.Concentrated paranaphthalene can be eluted by 2mL of acetonitrile.The elute efficiency can be achieved to 99%.2.N-(4-Vinyl)-benzyl iminodiacetic acid(VBIDA)was synthesized in our lab.Magnetic polystyrene-VBIDA material was prepared successfully by using azodiisobutyronitrileas the initiator,VBIDA as the monomer,the mixture of toluene and PEG2000(m/m=1/2)as the porogen and divinyl benzene as the cross-linker.Fourier infrared spectrum,Nuclear magnetic resonance hydrogen spectrum(1H-NMR)and Liquid chromatography-mass spectrometry(LC-MS)have been used to characterize VBIDA.Fourier infrared spectrum and thermogravimetric analysis(TG-DTG)hasbeen used to characterize the prepared material.The preparation and enrichment of the prepared material have been investigated by using Cu2+ as the target ion.The results showed that the adsorption effect of the prepared material on Cu2+ was remarkable.The maximum adsorption capacity can be reached to 72.32 mg/g.The adsorption efficiency of the prepared material on Cu2+was 93%.2 mL,0.1 mol/L EDTA can be chosen as the eluent and the elution rate was 95%.3.The preparation of magnetic polystyrene-VBIDA-polydopamine imprinted composite materials has been developed using tryptophan as a template.Fourier infrared spectrum,Solid surface fluorescence measurement,Thermogravimetric analysis and X-ray photoelectron spectroscopy(XPS)have been used to characterize the structure and properties of the prepared composite materials.The optimum preparation condition was as follows: the mass ratio of VBIDA to DVB was 1:1;the coating time of dopamine was 24 h.The adsorption performance and selectivity of the prepared composite material also have been investigated.The selective adsorption performance of the prepared composite material was obvious and the adsorption efficiency on tryptophan can be reached to 84%.The experimental results showed that the adsorption effect of composite material was relatively stable.2 mL,0.1 mol/L EDTA can be chosen as the eluent and the elution rate was 90%.In the process of experiment,the loss of the composite material was not observed.