Effects of selected parameters on decolorization and decomposition of acid orange 6

This study investigated the effects of controlling parameters, temperature, pH, ozone dose, and initial Acid Orange 6 (AO6) concentration on the degradation of target compounds. Decolorization and AO6 reduction were completed within 40 min of ozonation time for all examined cases. Significant amounts of total organic carbon (TOC) still remained by the end of experiments, suggesting that ozone could not oxidize all organic molecules to CO₂. Major findings from this study were as follow: (1) the decolorization of AO 6 dye was affected by ozone dose and pH; however, the effects of temperature contribution on apparent rate constant was limited. (2) TOC removal was affected by temperature significantly, but the affects of pH and ozone dose were limited. (3) The highest Y_SO42- level was about 0.70 as η_TOC was about 0.75, and the increment of Y_SO42- was accelerated as η_TOC > 0.4. (4) The η_TOC was proportional to the 7.64 m_O3R power of exponential term. (5) NO and NO₂ were found in off-gas that might provide the explanation of unbalance of nitrogen mass.