Degradation of remazol golden yellow dye wastewater in microwave enhanced ClO2 catalytic oxidation process

Experiments were conducted to investigate the removal of remazol golden yellow dye in order to assess the effectiveness and feasibility of microwave enhanced chlorine dioxide (ClO2) catalytic oxidation process. The catalyst used in this process was CuOn-La2O3/gamma-Al2O3. The operating parameters such as the ClO2 dosage, catalyst dosage, and pH were evaluated. The results showed that microwave enhanced catalytic oxidation process could effectively degrade remazol golden yellow dye with low oxidant dosage in a short reaction time and extensive pH range compared to the conventional wet catalytic oxidation. Under the optimal condition (ClO2 concentration 80 mg/L, microwave power 400 W, contacting time 1.5 min. catalyst dosage 70 g/L, and pH 7), color removal efficiency approached 94.03%, corresponding to 67.92% of total organic carbon removal efficiency. It was found that the fluorescence intensity in microwave enhanced ClO2 catalytic oxidation system was about 500 a.u. which was verified that there was much hydroxyl radical produced. Compared with different processes, microwave enhanced ClO2 catalytic oxidation system could significantly enhance the degradation efficiency. It provides an effective technology for dye wastewater treatment. (C) 2009 Elsevier B.V. All rights reserved.