Optimal conditions were achieved as 0.015 mmol Fe2+, 0.15 mmol H2O2, 20 mg/L initial dye concentration and pH = 3.5, for the Fenton process and 0.0125 mmol Fe2+, 0.3 mmol H2O2, 20 mg/L initial dye concentration and pH =3.5 for the photo Fenton process