Preparation Of Ion Exchange Magnetic Polymer Microspheres And The Application In Separation And Enrichment

The magnetic ion exchanger solves the problem that the ion exchanger is difficult to separate,difficult to regenerate,and has few times of repeated use,and has the advantages of being easy to be functionalized,capable of grafting various functional groups,and having a controllable particle size.Therefore,in this paper,the cation-exchanged magnetic polymer microspheres and the amphoteric ion exchange magnetic polymer microspheres were synthesized by the swelling-permeation method,and the magnetic chitosan microspheres were synthesized by phase inversion method,and then freed by surface atom transfer.Base polymerization,cation exchange polymer layer was formed on the surface of magnetic chitosan microspheres,and magnetic chitosan composite microspheres were obtained.The factors affecting the synthesis of magnetic microspheres were investigated in detail,and the magnetic microspheres were studied for biomacromolecules and small.The adsorption characteristics of molecular compounds were explored and applied to the separation and detection of protein,milk melamine and egg white lysozyme in blood samples.Chapter 1:The preparation and application of magnetic microspheres were summarized.The definition,classification and application of ion exchangers were introduced.The research progress of magnetic ion exchange microspheres was reviewed.Chapter 2:A novel monodisperse magnetic cation exchange microsphere（MPMs）was successfully prepared by swell-penetration method for studying protein adsorption characteristics.First,glyceryl methacrylate（GMA）and crosslinker were polymerized into polymer microspheres,and then the sulfonic acid group was grafted onto the surface of the microsphere by sulfonation reaction.Finally,Fe₃O₄ was successfully prepared by permeation deposition in cation exchange microspheres.The magnetic microspheres exhibited favorable selectivity on the adsorption of bovine serum albumin（BSA）.The maximum adsorption capacity was 289.1 mg g^-1.The effects of various factors on the adsorption properties for BSA,including adsorbent dosage,pH,ionic strength,initial protein concentration and adsorption time,were investigated.In addition,adsorption isotherms and kinetics were studied systematically.MPMs have been further successfully applied to the selective separation of serum albumin from human whole blood and the use of magnetic microspheres to separate melamine from milk samples.Chapter 3:Zwitterionic exchange magnetic microspheres（ZIEMMs）were prepared by swell-penetration method and used to adsorb cephalosporin antibiotics.The glycidyl methacrylate（GMA）and divinylbenzene（DVB）were polymerized into polymer microspheres,and the sulfonic acid group was grafted on the surface of the microsphere by reacting with Na₂SO₃,and then reacted with the ethylenediamine to graft the amino group.Finally,Fe₃O₄ were embedded into the microspheres by co-precipitation reaction.The effects of solution pH,ionic strength,initial concentration and adsorption time on the adsorption capacity of antibiotics were investigated.The adsorption isotherms and kinetics of cefazolin sodium were also investigated.The saturated adsorption capacities of ZIEMMs to cefepime,ceftazidime and cefazolin sodium were 33.46 mg g^-1,83.14 mg g^-1 and 111.5 mg g^-1,respectively.Chapter 4:First,the magnetic chitosan microspheres were synthesized by phase inversion method,then 2-bromoisobutyryl bromide was grafted onto the surface of the microspheres,and the glyceryl methacrylate was grafted by surface-initiated atom transfer radical polymerization（SI-ATRP）.Finally the epoxy group on the graft polymer was modified to sulfonic acid group in the presence of sodium sulfite to obtain magnetic cation exchange chitosan microspheres（MCECMs）.The MCECMs microspheres were characterized by SEM,FTIR and VSM.The size of the microspheres was single,the particle size was 160μm,and the saturation magnetization was 31.70 emu g^-1.The effects of pH and ionic strength on the adsorption capacity of lysozyme（LZM）were studied.The saturated adsorption capacity was 129.0 mg g^-1.The adsorption of LZM by MCECMs was a single layer adsorption and conformed to the pseudo first order kinetic equation.Further MCECMs were used to efficiently purify lysozyme from egg white.