Studies On Degradation Reactive Dye Wastewater Catalyzed By Heterogeneous Fenton Reaction

The Fenton reaction has its own unique advantage in the degradation of pollutants because of mild reaction conditions and high oxidation efficiency. However, the tradition homogeneous Fenton reaction works only on the pH range of 3-5, difficulty to resue the catalyst and forms the sludge after reaction that also contamination the water, which limit the use of these processes for industrial effluents. This thesis discussed to use CuMgAl hydrotalcite like compounds and their calcined oxides as the catalysts, and use the COD remove rate, decolourization rate and Cu2+ leaching as the evaluation criteria of catalyst acitivity and stability. The preparation condition of the catalyst was optimized, and the technique of hemegenous Fenton was fully researched. Meanwhile, there was preliminary research on improving the catalyst stability.CuMgAl hydrotalcite like compounds were synthesized by co-precipitation method and roasting reduction methods. XRD, FT-IR, TG-DTA and ICP were used to characterize these materials. We compared the activity and stability of CuMgAl hydrotalcite like compounds of different methods, and chosen Cu0.20Mg0.55Al0.25 as the catalysts. The effects of various parameters such as temperature, H2O2 dosage, reaction time and initial pH on the oxidation of dye were investigated.The results indicated the remove of reactive yellow X-6G were 93.5% and 100% in COD and color respectively at 70℃, pH=7,2h,3.05mmol H2O2,50mg Cu0.20Mg0.55Al0.25 and 1 g/L reactive yellow X-6G. Compared as homogeneous Fenton catalyst, the CuMgAl hydrotalcite like compounds had a high catalytic activity at a wide range of pH from 3-10, which greatly expanded the pH range of Fenton. And this catalytic system could be well applied for other dye wastewaters such as Reactive Brilliant Red K-2BP, Reactive Yellow X-GL, Anthraquinone Reactive Blue KN-R.Mg/Al supported Cu oxide catalysts were prepared by co-precipitation of Cu0.20Mg0.55Al0.25 Hydrotalcite like compounds as precursors, calcined. We compared the structure and stability of oxides of different calcination temperature, and found Cu containing mixed oxide (Cu0.20800) calcined at 800℃showed the high stability, it was used as catalyst on degradation of reactive yellow X-6G simulant wastewater. The results indicated the remove of reactive yellow X-6G were 77.6% and 100% in COD and color respectively at 1g/L reactive yellow X-6G. It also had a high catalytic activity at a wide range of pH from 3-10, and its could be well applied for other dye wastewaters such as Reactive Brilliant Red K-2BP, Reactive Yellow X-GL, Anthraquinone Reactive Blue KN-R. The recycling experiment implied that the catalyst was stable and can be reused.