Role of Ceric Ion (Ce4+) in the Sonosorption of Acid Red 114, Reactive Blue 21 and Basic Violet 16 Dyes on TiO2

Adsorption study of three textile dyes[Acid Red 114 (AR 114), Reactive Blue 21 (RB 21) and Basic Violet 16 (BV 16)] of different classes has been carried out on TiO₂ alone and in combination with rare earth ion [Ce⁴⁺], in the aqueous solutions, in the presence and absence of ultrasound. The complete removal of AR 114 and RB 21 were achieved in 5 minutes of sonication in the presence of rare earths while BV 16 was decolourised to only 21% even after 50 min. The experimental data was analysed using different adsorption isotherms, kinetics and adsorption mechanism. The isotherm data fitted very well with Langmuir model and the adsorption followed pseudo-second order kinetics. The presence of Ce⁴⁺ ions enhanced adsorption of anionic dyes on TiO₂ surface but decreased for basic dye. A mechanism of adsorption and the degradation of dyes have been proposed.