Degradation of an Anthraquinone Dye by Ozone/Fenton: Response Surface Approach and Degradation Pathway

<p>A coupled O<sub>3</sub>/Fenton process is applied to study the degradation efficiency of organic pollutants. The C.I. Acid Blue 80 (AB80), a kind of anthraquinone dye, is used as target contaminant. The results show that the combination of ozonation and Fenton process is a highly effective way of removing color from wastewater. Response surface methodology is applied to optimize the working conditions and the effects and interactions among initial pH (X<sub>1</sub>), mole ratio of H<sub>2</sub>O<sub>2</sub>/Fe<sup>2+</sup> (X<sub>2</sub>) and ozone flux (X<sub>3</sub>) are investigated. Regression equations determines that the best condition is that initial pH = 2.85, [H<sub>2</sub>O<sub>2</sub>]/[Fe<sup>2+</sup>] = 18.10 and ozone flux = 55.70 L.h<sup>−1</sup>. It turns out the relative error of 1.32% with the predicted model when the actual value which is 88.76% in the best condition, compared to the predictive value of 88.95% under same condition. UV-Vis and FT-IR analysis are used as an assisted technique to study degradation mechanism during the oxidation process. The intermediate products are determined by gas chromatography/mass spectrometry (GC/MS) analysis and the plausible degradation pathway is proposed.</p>