PREPARATION AND CHARACTERIZATION OF TIO₂ MICROSPHERES FOR ETHYLENE PHOTO-OXIDATION

A synthetic strategy leading to the formation of highly crystalline and spherical TiO₂ microspheres (TMS) is proposed. The microspheres were synthesized by means of spray drying process where a hydrothermally treated aqueous suspension containing TiO₂ nanoparticles (about 6 nm in diameter) was fed into the atomizer of the spray dryer. Optimized control of sol concentration, flow rate, chamber temperature and nozzle pressure of the spray dryer led to the formation of highly crystalline and regular spherical shaped TiO₂ microspheres in the range of 2-10 µm. TMS exhibits higher specific surface area as determined by the Brunauer-Emmett-Teller (BET) method. X-ray diffraction spectra show coexistence of anatase and rutile mixed phase with dominant anatase crystalline phase. Oxidation of ethylene under UV light irradiation has been achieved in the presence of TMS performed in an indigenously made closed Pyrex glass photocatalytic reactor.