Abstract:In this work optical properties of titanium dioxide nanoparticles were studied. Titanium dioxide nanoparticles were synthesized by the sol-gel method followed by a hydrothermal treatment using tetraisopropyl orthotitanate (TIOT) and 2-propanol. The synthesized samples were characterized by X-ray diffraction (XRD), UV-Vis diffuse reflectance spectroscopy (UV/DRS) and nitrogen adsorption-desorption methods. The bandgap energy was obtained using the Kubelka-Munk reemission function. The catalyst synthesized with a molar ratio of R 1 (water/TIOT) = 3.5 and R 2 (2-propanol/TIOT) = 15 has a predominately anatase phase. It also has a high photo degradation of methyl orange compared to TiO 2 Degussa P-25. A shift band gap energy of 3.27 was observed.

A coupled system of the photo-Fenton advanced oxidation technique and an aerobic sequential batch reactor (SBR) was used to treat wastewater from biodiesel production using either palm or castor oil. The photo-Fenton reaction and biological process were evaluated individually and were effective at treating the wastewater; nevertheless, each process required longer degradation times for the wastewater pollutants compared with the coupled system. The proposed coupled photo-Fenton/aerobic SBR system obtained a 90% reduction of the chemical oxygen demand (COD) in half of the time required for the biological system individually.