Intensification of the Chemical Degradation of Reactive Red 141 in the Presence of Ultrasound and Rare Earths [Lanthanum and Praseodymium]

Degradation of an azo dye, Reactive Red 141 (C₅₂H₂₆C₁₂N₁₄Na₈O₂₆S₈) in the aqueous solution has been carried out with ultrasound (US) and in combination with rare earth ions (La³⁺ and Pr³⁺). Both horn and tank type of sonicating devices, operating at 20 kHz and 250 W, were used for the degradation. A comparative study of continuous and pulsed mode of ultrasound induction has also been undertaken. Operational parameter, such as, initial dye concentration, pH and the presence of rare earth ions on the degradation of dye have been found to affect the degradation process . The degradation rate increased with increasing rare earth concentration, decreasing pH and initial dye concentration. The kinetic data fitted well with pseudo-first order kinetic model. The rate constant for the degradation process with US+RE was three times compared to US alone. The efficiency of various processes for the degradation of RR 141 dye was found to be in the order: US+La>US+Pr>US.