TITANIUM DIOXIDE-PHOTOCATALIZED OXIDATION OF 2,4-DICHLOROPHENOL

Titanium dioxide has been used as photocatalyst for the degradation of 2,4-dichlorophenol. This process takes place under UV-illumination ob taining high yields for diluted aqueous solutions. The yield of 2,4-di chlorophenol oxidation depends on the irradiation time, the incident l ight intensity, the mass of semiconductor in suspension, the initial c oncentration and very slightly on the pH and temperature. The initial rate values of 24-dichlorophenol oxidation follows Langmuir-Hinshelwoo d kinetics, with a rate constant and an equilibrium adsorption constan t of 4.5 x 10(-5) M/min and 3.2 x (103)/M, respectively, at 25 degrees C. From this data it is assumed that the oxidation of 2,4-dichlorophe nol occurs through reaction with OH radicals originated from valence b and processes in the surface-hydroxylated TiO2 particles under illumin ation.