Study On Treatment Of Azo Dye Waste Water With Heterogeneous Catalytic Ozonation

Orange G is widely used commercial azo dye stuff. Because of its good solubility in water and molecular stability, traditional wastewater treatment methods, such as flocculati on and activated sludge process, can’t work well with Orange G wastewater. It is suggested that catalytic ozonation processes be applied to treat the wastewater. The γ-Al2O3and γ-Al2O3carrier preparation of new type catalysts was respectively used as the catalyst in this research and the reaction mechanism was analyzed.Study on the degradation of azo dye orange G by catalytic ozonation with γ-Al2O3and ozone was carried out in this paper. The influences of catalyst particle size, initial pH and ozone concentration on the removal efficiency of orange G were investigated. Furthermore, the synergistic effect between γ-Al2O3and O3was employed. Reaction mechanism of orange G degradation by catalytic oxidation were preliminary studied, which by the addition of tert-butyl alcohol and UV-Vis absorption spectrum. Results showed that compared with γ-Al2O3and ozonation alone, the integrated process by O3/γ-Al2O3could improve the removal of chroma and COD with an obvious synergistic effect, and reveal well synergism. The removal efficiency of orange G (1000mg/L) was of99.9%and the COD removal efficiency was of76.1%after120min reaction. Both hydroxyl radical and O3played role on the degradation process of Orange G by the addition of hydroxyl capture tert-butyl alcohol by O3/γ-Al2O3.The FeOx catalysts were synthesized by impregnation method, and then the heterogeneous phase catalytic ozonation system was established. Through the catalytic ozone oxidation simulated dye wastewater, catalyst type selection and preparation of the optimization of the process. The results show that, FeOOH/γ-Al2O3catalytic ozonation treatment effect is better than that of Fe2O3/γ-Al2O3catalytic effect during treating Orange G wastewater under the condition of same.FeOOH/γ-Al2O3was used in catalytic ozonation degradation of azo dye orange G. Researches reveal that FeOOFI/γ-Al2O3catalyst for orange G solution shows good catalytic activity. Under the reaction conditions of the initial concentration of1000mg/L, catalyst load of0.1mol/L, the additive amount of10g/L, chroma, COD and TOC removal rate reached99.98%,93.94%and93.94%respectively after30min. Because of oxidation in the process of dye molecular structure to destroy, generate a small molecule acid, solution acidification, the initial pH in the reacting system value was also found to decrease from pH5.7to2.8. Hydroxyl radical played role on the degradation process of Orange G by the addition of hydroxyl capture tert-butyl alcohol with FeOOH/γ-Al2O3.