AbstractThe treatment of textile dyeing and finishing wastewaters by conventional methods, such as biological, physical and chemical processes or combinations thereof, are in common practice but have unique drawbacks, namely, a number of refractory chemicals in the effluents and difficulty in the complete removal of color. The study described herein is an investigation of an advanced oxidation treatment of a common azo dye, Remazol Black-B, widely used in textile dyeing and finishing operations. The investigation was focused on monitoring the degradation and toxicity reduction of an aqueous solution of the dye up to 30 min of treatment by a UV/H