Sonochemical synthesis of holmium doped zinc oxide nanoparticles: Characterization, sonocatalysis of reactive orange 29 and kinetic study

•Degradation of reactive orange 29 by sonocatalytic process.•Investigation of the effective operational parameters on degradation efficiency.•Application of Ho-doped ZnO nanoparticles as sonocatalyst in the sonocatalytic process.•Significantly decline in the dye concentration during sonocatalytic process.

The sonochemically synthesized Ho-doped ZnO nanoparticles were characterized by XRD, SEM, TEM, and XPS techniques. The sonocatalytic degradation of Reactive Orange 29 (RO29) was greater than that with sonolysis alone. DE% declines with the addition of chloride, carbonate, sulfate, and tert-butanol as radical scavengers. Addition of potassium periodate, peroxydisulfate, and hydrogen peroxide as enhancers improves DE%. The results demonstrate proper reusability of the doped sonocatalyst. Degradation intermediates were identified by gas chromatography–mass spectrometry (GC–MS). Using nonlinear regression analysis, an empirical kinetic model was developed to predict the pseudo-first-order constants (kapp) as a function of the operational parameters.

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