Decolorization of dyes using UV/H₂O₂ photochemical oxidation

This work explored the potential of ultraviolet light/hydrogen peroxide (UV/H₂O₂) photochemical oxidation technology for treating textile dyeing effluent. The effects of dye class and structure, dyebath concentration, radiation intensity, and hydrogen peroxide level on a UV/H₂O₂ system's ability to decompose and decolorize dyes were studied. To anticipate the economical viability of the technology, calculations projecting the scaled-up operating costs were also performed. Results indicated that acid, direct, basic, and reactive dyes appeared to be viable candidates for further in-plant treatment trials using photochemical oxidation treatment technology. Dye structures specifically involved in this research included disazo, azo, stilbene, polyazo, oxazine, triarylmethane, disazovinyl sulfone, triazine, anthraquinone, and indigoid. The disperse and vat dyes did not appear to be viable for future in-plant trials. Limited dye solubility seemed to have hindered the UV/H₂O₂ degradation of these two dye classes.