Degradation of a persistent organic dye from colored textile wastewater by ozonation

The effect of ozonation on the decolorization and degradation of an anthraquinone dye (C.I. Reactive Blue 19), performed in a laboratory scale cylindrical batch reactor, was studied. UV–Vis, ion chromatography (IC), chemical oxygen demand (COD) and total organic carbon (TOC) analyses were employed. The effect of operational parameters on decolorization such as ozone dosage, pH, dye concentration and the electrolytes was studied. Results showed that the ozonation was a very effective method for reactive dye decolorization. A rapid decrease of pH during the ozonation process gave evidence for production of acidic by-products. Sulfate, nitrate, formate, and acetate were identified as main oxidation products by ion chromatography. The reduction of COD and TOC showed partial degradation and mineralization of this dye.