Table 2.

A summary of the removal of azo dyes by different AOPs.

Process	Experimental conditions	Performance		Reference
		Removal (%)	kobs (min−1)
HC/ZVI/sulfite	[DR83]0 = 50.0 mg/L, [ZVI]0 = 200.0 mg/L, [sulfite]0 = 250.0 mg/L, pH = 3.0, airflow = 3.0 L/min, and reaction time = 60 min	95	0.035	Present study
UV/Cl	[DR83]0 = 50.0 mg/L, [Cl]0 = 1000.0 mM, pH = 3.0, UV fluence = 6.0 mW/cm2, and reaction time = 60 min	93	0.025	[7]
PL/H2O2	[DR83]0 = 30.0 mg/L, [H2O2]0 = 900.0 mg/L, fluence = 96. J/cm2, and pH = 11.0	76	0.027	[1]
Electrooxidation	[DR83]0 = 150.0 mM, NaCl = 5.0 N, density = 5.0 mA/cm2, and contact time = 60 min	–	0.074	[4]
US/PS	[Naphthol Blue Black]0 = 5 mg/L, [PS]0 = 0.5–1.0 mg/L, frequency = 585 kHz, power = 80 W, and reaction time = 20 min	95	–	[50]
HC/ZVI/H2O2	[Orange G] 0 = 40 mg/L, [ZVI]0 = 0.7 g/L, [H2O2]0 = 0.01 g/L, pH = 3.0, and reaction time = 20 min	74.6	–	[51]
HC/Fenton	FeSO4·7H2O:H2O2 = 1:5, pH = 6.8, pressure = 5 bar and reaction time = 60 min	97.7	0.002	[52]