Hydrodynamic cavitation as an advanced oxidation technique for the degradation of acid red 88 dye

Abstract

In the present work, degradation of Acid Red 88 dye (AR88) has been carried out using one of the advanced oxidation processes, namely hydrodynamic cavitation (HC). The effect of various operating parameters such as inlet pressure, initial concentration of dye, pH of solution, addition of H₂O₂, and a catalyst (Fe-TiO₂) on the extent of decolorization and mineralization have been studied with the aim of maximizing the extent of degradation. The degradation of AR88 was found to follow first order kinetics under the condition examined. The study revealed that the extent of degradation increased with an increase in the initial dye concentration and the rate of degradation was found to be dependent on the solution pH. The degradation of AR88 is enhanced with the addition of H₂O₂ and catalyst (Fe-TiO₂). The comparative study of hydrodynamic cavitation and acoustic cavitation suggested that hydrodynamic cavitation is more energy efficient and gives higher degradation as compared to acoustic cavitation for equivalent power/energy dissipation. To observe the complete mineralization of the dye molecule, the total organic carbon (TOC) content was also measured at optimized condition for different experimental sets.