Abstract: Provided is a method of fabricating silica-titania nanoporous composite powder by controlling a pore size. In more particular, a method of fabricating silica-titania nanoporous composite powder, using a spraying and heating reactor including an ultrasonic droplet generator and a cylindrical electric furnace, comprises the steps of: generating droplets of a mixture suspension from a colloidal suspension prepared by mixing silica (SiO2) and titania (TiO2) nanopowders and organic template (PSL: polystyrene latex) powder, by the ultrasonic droplet generator of the spray-heating reactor; generating a silica-titania-organic template nanoporous composite powder having pores within the range of 20˜100 nm in size through preparing silica-titania-organic template (SiO2—TiO2-PLS) composite particles and removing the organic template while passing the mixture suspension in the cylindrical electric furnace by a carrier gas; and collecting the generated nanoporous material by a particle collector.

Abstract: Disclosed is a method for producing a cerium dioxide nanopowder by flame spray pyrolysis. The method comprises dissolving a cerium compound in an organic solvent to prepare a precursor solution, atomizing the precursor solution into microdroplets using an ultrasonic atomizer, transferring the microdroplets together with an argon gas as a carrier gas to a central portion of a high-temperature diffusion flame burner, subjecting the microdroplets to pyrolysis and oxidation in the central portion of the diffusion flame burner to produce a cerium dioxide nanopowder, and collecting the cerium dioxide nanopowder using a collector. According to the method, a cerium dioxide nanopowder can be continuously produced on a large scale by flame spray pyrolysis. In addition, the particle size and uniformity of the cerium dioxide nanopowder can be controlled by appropriately selecting the kind of the solvent and the concentration of the raw material.

Abstract: In accordance with one embodiment, a method of modifying the surface of silica nanopowder by a spray heating process is provided. In the method, surface characteristics of silica nanopowder are modified from hydrophilic to hydrophobic. A colloidal suspension including silica nanopowder and a surface modifier which are dissolved in ethanol is sprayed and thermally dried so that the surface characteristics of silica nanopowder are modified by the surface modifier coated on the surface of silica nanopowder. In the method, silica nanopowder surfaces are modified from hydrophilic to hydrophobic by controlling concentration and type of a surface modifier and heating temperature.

Abstract: There is provided a method of preparing silica (SiO2) nanoparticles from siliceous mudstone which is silica mineral sources, using a chemical reaction. The method of preparing silica nanoparticles from siliceous mudstone comprises: solving a silica constituent into a sodium silicate aqueous solution by a sodium hydroxide leaching reaction of the siliceous mudstone (S100); performing ion exchange to remove a sodium constituent from the sodium silicate aqueous solution and to prepare a silicate aqueous solution (S200); and performing flame spray pyrolysis to prepare silica nanoparticles with an average particle dimension being in a range of 9 to 57 nm from the silicate aqueous solution.

Abstract: Provided is a method of fabricating silica-titania nanoporous composite powder by controlling a pore size. In more particular, a method of fabricating silica-titania nanoporous composite powder, using a spraying and heating reactor including an ultrasonic droplet generator and a cylindrical electric furnace, comprises the steps of: generating droplets of a mixture suspension from a colloidal suspension prepared by mixing silica (SiO2) and titania (TiO2) nanopowders and organic template (PSL: polystyrene latex) powder, by the ultrasonic droplet generator of the spray-heating reactor; generating a silica-titania-organic template nanoporous composite powder having pores within the range of 20˜100 nm in size through preparing silica-titania-organic template (SiO2—TiO2—PLS) composite particles and removing the organic template while passing the mixture suspension in the cylindrical electric furnace by a carrier gas; and collecting the generated nanoporous material by a particle collector.

Abstract: The invention relates to a method for making silica nanoparticles using a flame reactor, which includes a droplet spray having a two-fluid nozzle and a burner of a quintuple tube structure. In this method, droplets of silicon alkoxide as liquid Si compound are sprayed through the droplet spray of the flame reactor. A flame is generated by the flow of inert gas, oxygen, hydrogen and air simultaneously into the burner of the flame reactor. The liquid Si compound is delivered through the flame of the burner to produce silica nanoparticles having a mean particle size ranging from 9 nm to 68 nm. Resultant nanoparticles are collected and recovered in a particle collector. The droplets sprayed under high pressure from a silicon alkoxide solution are directly oxidized in the flame, thereby producing spherical silica nanoparticles.

Abstract: The invention relates to a method for making silica nanoparticles using a flame reactor, which includes a droplet spray having a two-fluid nozzle and a burner of a quintuple tube structure. In this method, droplets of silicon alkoxide as liquid Si compound are sprayed through the droplet spray of the flame reactor. A flame is generated by the flow of inert gas, oxygen, hydrogen and air simultaneously into the burner of the flame reactor. The liquid Si compound is delivered through the flame of the burner to produce silica nanoparticles having a mean particle size ranging from 9 nm to 68 nm. Resultant nanoparticles are collected and recovered in a particle collector. The droplets sprayed under high pressure from a silicon alkoxide solution are directly oxidized in the flame, thereby producing spherical silica nanoparticles.

Abstract: There is provided a method of preparing silica (SiO2) nanoparticles from siliceous mudstone which is silica mineral sources, using a chemical reaction. The method of preparing silica nanoparticles from siliceous mudstone comprises: solving a silica constituent into a sodium silicate aqueous solution by a sodium hydroxide leaching reaction of the siliceous mudstone (S100); performing ion exchange to remove a sodium constituent from the sodium silicate aqueous solution and to prepare a silicate aqueous solution (S200); and performing flame spray pyrolysis to prepare silica nanoparticles with an average particle dimension being in a range of 9 to 57 nm from the silicate aqueous solution.