Preparation And Adsorption Properties Of Amino Functionalized Core-shell Microspheres

Magnetic Fe₃O₄ nanoparticles have been widely applied in industrial catalysis,biomedical and transducer for its unique structure and magnetic properties.Recently,magnetic nanocomposites and their surface functionalized materials have shown great prospect in analytical chemistry.Therefore,preparation of novel magnetic based composites and their application have attracted extensive interests of researchers.In this paper,preparation,surface functionalization and adsorption application of magnetic composites were investigated.And the following results were obtained:?1?We prepared Fe₃O₄ nanoparticles in ethylene glycol/sodium acetate / iron?III?chloride hexahydrate system through solvothermal method.And studied the effect of different surfactants like polyethylene glycol,sodium citrate and ethylene diamine on the formation and morphology of Fe₃O₄ nanoparticles.The morphology of obtained magnetic nanoparticles was spherical with relatively complete surface,but also with the wide particle size distribution when the polyethylene glycol and sodium citrate were used as surfactants.While use ethylene diamine as surfactants,the monodispersed spherical nanoparticles with roughly surface,and uniform particle size distribution was obtained,and the average particles size was about 120 nm.?2?The Fe₃O₄ nanoparticles were coated with an amorphous silica with the thickness of about 4 ¹0 nm through sol-gel method?denoted as Fe₃O₄@nSiO₂?,which can protect it from being oxidized and coagulated.The thickness of silica layer can be adjusted by the different added amount of tetraethylorthosilicate?TEOS?.?3?A mesoporous silica layer with the thickness of about 40 nm were coated on to the surface of Fe₃O₄@nSiO₂ nanoparticles through template method by using cetyl trimethyl ammonium bromide?CTAB?as template?denoted as Fe₃O₄@nSiO₂@mSiO₂?.And then the obtained materials were treated by 3-aminopropyl triethoxysilane?APTES?with different concentration,and the final materials with different amino amounts was finally prepared successfully?denoted as NH2-MMs?.?4?The synthesized materials was used as adsorbent for the adsorption of Allura red in aqueous solution.The experiments indicated that: the optimum adsorption was obtained at pH =2;The adsorption process can reach an equilibrium after 3 min with an equilibrium adsorption capacity of 29.6 mg/g;And adsorption process is well in line with pseudo-second-order equation,adsorption isotherm can be well fitted by Freundlich model and adsorption process is mainly physical adsorption.?5?The prepared material was used for pre-treatment of actual samples.And the chromatographic separation and analysis method was established and investigated.?6?The Fe₃O₄/WMCNTs composites was synthesized by one-step solvothermal method,and investigated its adsorption properties on Allura red.