Comparing the degradation of azo dyes through heterogeneous ozonation processes using different catalysts.

Dyes	Catalyst	Optimal processing conditions	Degradation efficiency	References
AOII	CaFe2O4 nanoparticles	pH 9, CaFe2O4: 1.0 g L−1, AOII concentration: 100–500 mg L−1	85% TOC removal	This study
Methyl orange	Ni-based layered double hydroxides (Ni-LDHs) nanomaterials	Reaction time: 60 min, pH 9; ozone flow rate: 109 mg h−1; catalyst dosage: 1 g L−1; initial COD: 620 mg L−1	72% COD removal	54
Methyl orange	MnO2 nanoparticles	Initial pH 5.8, reaction time: 60 min, methyl orange concentration: 90 mg L−1, catalyst dosage: 20 mg L−1	98.37% methyl orange removal	68
AOII	ZnO nanoparticles	pH range: 4.6–9.6, ZnO nanoparticle: 1.0 g L−1, AOII: 50–200 mg L−1	90% TOC removal	70
Acid blue 113	Fe2O3/MoS2 nanocomposite	Initial pH 6.4, nanocomposite: 20 mg, ozone flow: 0.2 g L−1 h−1, and reaction time: 45 min	99.0% AOII removal	69
Reactive blue 5	Nano-ZnO/perlite	pH 11, reaction time: 60 min, dye concentration: 100 mg L−1, initial TOC: 31.45 mg L−1, catalyst dosage: 12 mg L−1	92% TOC removal	17
Reactive red 24	Iron slag	pH 11, catalyst dosage: 1.5 g L−1, initial reactive red 24 concentration: 300 mg L−1, inlet O3: 3.038 g h−1, H2O2 concentration: 100 mg L−1, reaction time: 40 min	84% COD removal	26
Active brilliant red X-3B	Natural mineral brucite	pH 9.24, catalyst dosage: 0.5 g L−1, active brilliant red X-3B: 500 mg L−1, reaction time: 30 min	32% COD removal	67