A comparative study on the degradation of RB-19 dye in an aqueous medium by advanced oxidation processes

The effectiveness of photolysis (UV), peroxidation (H2O2), peroxidation combined with UV light (UV/H2O2), Fenton reagent (H2O2/Fe2+), and the photo-Fenton process (H2O2/Fe2+/UV) at degrading the textile dye Reactive Blue 19 was evaluated. The efficiency of the photo-Fenton process for degrading raw textiles and biologically pre-treated effluents was also evaluated. H2O2 (100–800 mg L−1) and UV light did not degrade dye when used separately. The UV/H2O2 process was effective but slow: 91% of dye degraded within 3 h of reaction at a concentration of 500 mg L−1 H2O2. Fenton reagent reduced dissolved organic carbon by 36.8% and color was reduced by >98% within a few minutes of reaction. The photo-Fenton process was the most efficient, reducing 94.5% of dissolved organic carbon and 99.4% of color. The combination of a biological system and the photo-Fenton process degraded a high level of textile effluent degradation, reducing dissolved organic carbon by 88%, color by 85%, chemical oxygen demand by 80%, and biochemical oxygen demand by 93%. ► AOPs were applied to degrade RB-19. ► Photo-Fenton process was the most efficient in the degradation of this dye. ► Degradation of both raw and pre-treated textile effluents was evaluated. ► Photo-Fenton process showed higher potential to eliminate color in wastewaters. ► Biological pre-treatment of the substrate improved the photo-Fenton efficiency.