Ultrasound-assisted degradation of Procion Brilliant Orange M-2R dye using ultrasonic flow cell combined with oxidants

BACKGROUND

The current research investigates the degradation of Procion Brilliant Orange M-2R utilizing an ultrasonic (US) flow cell in conjunction with oxidants. The treatment scheme involved optimizing the pH (3–8), operating power (750–1200 W) and recirculation flow rate (200–800 mL min⁻¹) to achieve maximum decolorization through the use of only the US flow cell followed by combination studies with various oxidants for intensification.

RESULTS

The highest decolorization attained was 74.7%, while mineralization reached 24.6% using an individual US flow cell under optimum conditions of initial concentration of dye of 20 ppm, pH of 3, power of 1200 W and circulating flow rate of 400 mL min⁻¹. Subsequently, the efficacy of various combinations of the US flow cell with oxidants, specifically US + H₂O₂, US + Fenton's reagent, US + potassium persulfate (KPS) and US + FeSO₄⋅7H₂O + KPS, was studied confirming that higher decolorization of 93%, 93.8%, 92.4% and 95.5% for those combinations, respectively, was obtained. The decolorization followed second-order kinetics across all methods employed, and the obtained rate constants confirmed the synergism for the combinations. Toxicity assessments, alongside high-resolution liquid chromatography–mass spectrometry analysis, demonstrated that no toxic intermediates were introduced into the reaction mixture during the treatment. Cavitational yield and treatment cost were also estimated to compare various approaches used in the work.

CONCLUSION

Overall, the combination of the US flow cell with FeSO₄⋅7H₂O and KPS demonstrated maximum efficacy in degrading Procion Brilliant Orange M-2R dye. © 2025 Society of Chemical Industry (SCI).