Preparation Of Functional Microspheres Based On Cenosphere

Cenosphere, as a new kind of powder materials, is endowed with manycharacteristics,such as hollow, light weight, small size and non-toxicity. In this paper, electroless silverplating on cenoshpere was carried out based on silver mirror reaction without usingcoarsening and activation. The optimum condition for silver deposition on cenosphrere wasemployed by using the single factor analysis method. Silver was also deposited oncenosphere modified with silane coupling agent. The effects of the concentrations of silvernitrate, glucose, sodium hydroxide and anhydrous alcohol and the loadage of cenosphereon the weight increasing percentage, utilization ratio, conductivity and fastness ofAg-coated cenosphere were discussed. The surface morphology and structure werecharacterized by FT-IR, SEM and XRD techniques. It was found that as compared with thecolloidal palladium activation and silver ammonium solution activation methods, theuniform and compact coating with superior conductivity and high fastness could beobtained with saline coupling pretreatment.Magnetite （Fe3O4） is a typical ferrimagnetic material with excellent superparamagnetic, wave absorbing properties, but excessive density. In the paper, Fe3O4nanoparticles were deposited on the surface of cenosphere by using homogeneousprecipitation and hydrothermal synthesis technique, respectively. The effects of theconcentrations of ferrite, urea and ethanol, the ratio of Fe2+and Fe3+on the morphologyand structure of Fe3O4-coated cenosphere were discussed. The surface morphology,chemical and phase constituents, crystalline structure, magnetic behavior werecharacterized by scanning electron microscope （SEM）, energy dispersive spectroscopy（EDX）, X-ray diffraction （XRD）, vibrating sample magnetometer （VSM）. The resultsshowed that cenosphere with superparamagnetic property was deposited with a layer ofFe3O4film by using homogeneous precipitation and hydrothermal synthesis techniques,respectively. The saturation magnetization intensity of cenosphere prepared byhydrothermal synthesis method was35.72emu·g-1.TiO₂nanoparticle has excellent ultraviolet shielding ability, anti-bacteria andphotocatalytic activity. Cenosphere was deposited with a layer of TiO₂nanoparticles using titanium sulfate and butyl acetate by hydrothermal method, respectively. The resultsshowed that cenosphere deposited with a layer of TiO₂nanoparticle could block ultravioletlight. Furthermore, multi-functional cenosphere coated with Fe3O4/TiO₂/Ag was preparedbased on the above methods. It was not only has excellent photocatalytic activity, but alsohas superparamagnetic properties.