SYNTHESIS, CHARACTERIZATION, AND PROPERTIES OF MICROEMULSION-MEDIATEDNANOPHASE TIO2 PARTICLES

Nanophase TiO2 particles, with typical particle sizes in the range of 20-50 nm, have been synthesized using a microemulsion-mediated process . In this process, the aqueous cores of water/Triton X-100/hexanol/cyc lohexane microemulsions have been used as constrained microreactors fo r the precipitation of precursor titanium hydroxide. The hydroxide par ticles thus formed were separated, dried, and calcined at different te mperatures to form nanoparticles of TiO2. In order to see the phase tr ansition temperature, thermogravimetric analysis/differential thermal analysis studies were performed on the precursor hydrodoxide particles . The average particle size of these particles was determined by trans mission electron microscopy, BET surface area and line broadening by X -ray diffraction. Phase transformation of these particles was confirme d by X-ray diffraction. The attenuation of ultraviolet radiation incre ased as the particle size decreased. As a catalyst for the photodegrad ation of phenol, only the anatase form of TiO2 showed significant degr adation of phenol, whereas the rutile form of TiO2 was totally inactiv e for this reaction.