Fabrication of spherical silica aerogel/magnetite nanocomposite particles

Fe3O4/SiO2 nanocomposite particles were synthesized from a hydrophobic Fe3O4 suspension, prepared by precipitating Fe (II) and Fe (III) chlorides and using a hydrophobic SiO2 wet gel from a silicic acid solution derived from a sodium silicate (water glass) solution. Fe3O4 nanoparticles having a crystallite size of ~10 nm embedded in SiO2 aerogel can be successfully fabricated by mixing the Fe3O4 suspension and silica wet gel in n-hexane. It was clearly observed that the Fe3O4 nanoparticles were well crystallized and homogeneously dispersed in the SiO2 aerogel. The Fe3O4/SiO2 nanocomposite particles exhibited superparamagentic behavior. The saturation magnetization was determined to 34.5, 18.2, and 8.3 emu/g for 90 wt% Fe3O4, 70 wt% Fe3O4, and 50 wt% Fe3O4/SiO2 nanocomposite particles, respectively.