Mechanistic analysis of hybrid sono-photo-ferrioxalate system for decolorization of azo dye

• Mechanistic analysis of sono-photoferrioxalate system for azo dye decolorization.
• Identification of relative contribution of each AOP and interactions among AOPs.
• Approach of coupling experiments with simulations of cavitation bubble dynamics.
• Contribution of sonolysis in hybrid AOPs is mostly of physical nature.
• Significant contribution of O2
• − and HO2
• radicals to decolorization.

This paper has attempted to identify the physical mechanism of the hybrid advanced oxidation process (HAOP) of sono-photo-ferrioxalate for azo dye decolorization. An approach of coupling experimental results with simulations of cavitation bubble dynamics has been adopted. Concurrent analysis of simulations of cavitation bubble dynamics and experimental results have revealed interesting links between physics of ultrasound/cavitation, and chemistry of decolorization. The role of ultrasound and cavitation in HAOP is revealed to be of physical nature. Oxidizing radicals produced via photo-ferrioxalate system contribute mostly to decolorization. Physical effect of strong micro-convection induced by ultrasound/cavitation in reaction system helps effective utilization of these radicals. Among three radical species, viz  . O2
• −,
• OH and HO2
• , produced via photo-ferrioxalate system the contribution of O2
• − and HO2
• radicals to decolorization is equally significant as that of
• OH radical with the highest oxidation potential.

Reaction meachnisms in sono-photo-ferrioxalate system Figure optionsDownload as PowerPoint slide