A Kinetic Study on Photocatalytic and Sonophotocatalytic Degradation of Textile Dyes

Abstract

In the present study, an artificial effluent solution was used for investigating the degradation of dyestuffs by sonolytic, photocatalytic and sonophotocatalytic methods in the presence of TiO₂. This solution contained the mixture of C. I. Acid Red 27, C. I. Disperse Red 92 and C. I. Acid Orange 10 dyestuffs. The effect of parameters such as initial concentration of dyestuffs, light intensity, the amplitude of sonolysis and temperature on the degradation processes was studied. When the degradation data of the three methods for constant parameters were compared after 80 min.; the degradation values were approximately 19, 68 and 82 % for sonolytic, photocatalytic and sonophotocatalytic processes respectively. According the results purely sonolysis has an inconsiderable effect for the degradation of dyes. Also, when the parameters were applied for determining the kinetics of processes the sonophotocatalytic degradation rate followed pseudo-first order kinetics with respect to concentration of dyestuff analogously photocatalytic process. It was observed that the reaction rate accelerated in the presence of ultrasound energy in the course of the experiments. The most effective process was sonophotocatalytic on the degradation and an equation was derived including the effect of sonolysis for sonophotocatalytic degradation kinetics.