Nano Mno < Sub > 2 < / Sub > / Fe < Sub > 3 < / Sub > O < Sub > 4 < / Sub > Preparation, Characterization And Application Research Of Magnetic Particles

In recent years, nano-composite materials consisting of core and shell have beenattracting great interest and attention of researchers because the potential applicationin catalysis, environmental protection, and especially biomedical use.In this paper, we present an approach to synthesize and characterize MnO₂/Fe₃O₄composite particle by homogeneous precipitation with Fe₃O₄as the magnetic core andMnO₂as the shell, where the Fe₃O₄nanoparticles were prepared by co-precipitationmethod and the MnO₂/Fe₃O₄composite core-shell structure were synthesized viahydrolyzation of MnSO4with precipitant.Using the prepared Fe₃O₄particles of10nm-25nm as magnetic cores, wesynthesized MnO₂/Fe₃O₄composite particles with MnO₂as the shell by homogeneousprecipitation. Their structure and morphology were characterized by X-ray diffraction（XRD）, X-Ray Photoelectron Spectroscopy （XPS）, transmission electronicmicroscopy （TEM）, Fourier transform infrared spectra （FTIR） and vibration-samplemagnetometer （VSM）. We show that uniform MnO₂coating of ca.3nm thick on Fe₃O₄particles can be obtained. The composite particles have better dispersivity than thestarting materials, and exhibit super paramagnetic properties with saturatedmagnetization of33.5eum/g.The application of composite particles also was studied in this paper. We lookedinto their adsorption ability and catalysis ability by decolorizing methyl orangesolution respectively.At first, we studied the factors including pH value of the solution, contact timewhich may influence composite particles’ adsorption ability in decomposing methylorange. The results show us that the composite particles perform better adsorptionability with lower pH value of solution. Under the condition of pH=1.3, with the samedosage1g/L, they had the best adsorption ability, and the time of reaching the highestdecoloration rate94.33%was50min.Then, the catalysis ability of composite particles was also researched by MnO₂catalyzing H2O2. In this article, we mainly studied the factor dosage which mayinfluence composite particles’ performance in decomposing methyl orange. And wefound that the best dosage was1g/L. Under this condition, the highest decolorationrate was95.66%.All experiments have testified that composite particles have excellent adsorption and catalysis ability. So the synthesized materials may find wide applications in thefield of dyestuff adsorption, and these composite particles are recyclable due to theirmagnetism.