Effects of some water-quality and operating parameters on the decolorization of reactive dye solutions by ozone

The ozonation of reactive dye solutions has been investigated. Results of s tudies on ozone mass transfer indicated that the volumetric mass transfer c oefficient of ozone increased with the following water-quality and operatin g parameters: pH, initial dye concentration, applied ozone dose, and temper ature. A model was developed to predict the volumetric mass transfer coeffi cient of ozone from the above parameters. The results of kinetic studies sh owed that ozonation of the aqueous reactive dye was a pseudo-first-order re action with respect to the dye. The apparent rate constant increased with t he pH, applied ozone dose and temperature, however, it declined logarithmic ally with the initial dye concentration. Meanwhile, Ozonation enhanced the biodegradability and reduced the COD of the reactive dye wastewater effecti vely.