Decolorization of Direct Blue 71 using UV irradiation and ultrasound in the presence of TiO₂catalyst

The sono, photo, and sonophotocatalytic degradations of Direct Blue 71 (DB71) in the presence heterogeneous TiO2 catalyst were studied at 20 kHz using ultrasonic (US) power of 95 W and aqueous temperature of 20°C for 20 min. The effects of various operational parameters such as the concentration of the dye, pH, and amounts of catalysts on the sonochemical degradation were also investigated. Sonochemical degradation of DB71 was strongly affected by initial substrate concentration, amounts of catalysts, and pH. Acidic pH was favored for the sonocatalytic degradation of DB71 using catalysts. The hybrid technique of sonocatalytic degradation was compared with the individual techniques of catalysis, sonolysis, and photocatalysis. The US degradation of dye was enhanced by catalyst addition. The structure and morphology of the catalyst were investigated using scanning electron microscopy and X-ray diffraction pattern.