Photocatalytic decolorization of rhodamine B by immobilized TiO2 onto silicone sealant

The photocatalytic performance of immobilized TiO2 supported on silicone sealant was evaluated using the photocatalytic oxidation of rhodamine B (RhB) under weak illumination conditions. Three 8 W germicidal lamps were used as the light source and the reactor volume was 1.7 l. The optimum dosage of immobilized photocatalyst was 210.7 g/l (TiO2 weight percentage: 15%). The initial decolorization rate constants of RhB in an aqueous solution were determined in the presence or absence of immobilized TiO2 and UV irradiation in order to study each decolorization effect due to adsorption onto the immobilized TiO2, direct photolysis by UV irradiation and photocatalytic decolorization. The order of initial decolorization rate constant was photocatalytic oxidation > adsorption > photolysis. The initial decolorization rate constant of the RhB by the immobilized TiO2 was higher than that of the powder TiO2. The used immobilized photocatalyst retained a constant photocatalytic activity.