Construction Of Polyphase Fenton Catalytic System And Its Application In Fuel Wastewater

At present, the severe shortage of water resources around the world, are in urgent need of the sustainable utilization of water, and the biggest obstacle to achieving sustainable development of water is the governance of industrial waste water. Dye waste water in industrial waste water emissions increased year by year, and dye wastewater with high COD, high chromaticity, high toxicity and refractory etc, the traditional physical and chemical methods are difficult to achieve effective treatment effect. Therefore, advanced oxidation technology application in dye wastewater has become a hot research topic, in which heterogeneous Fenton catalyst development and performance research is key.In this paper, methylene blue (MB) and methyl orange (MO) as simulated wastewater, using magnetic Bentonite/H2O2 and Chitosan(Ch)-Fe2+/H2O2 systems on the catalytic degradation, respectively. In order to determine the best reaction conditions, using the single factor analysis method to study the main factors of the substrate degradation. In addition, through repeated use frequency and the dissolubility of iron ion to examine the stability, catalytic activity, service life of the catalyst.The results of the first part experimental:Establish Fe3O4-bentonite/H2O2 heterogeneous Fenton system to degrade MO waste water, the reaction can achieve balance after 20 min, and the decolorization rate was 96.72%. Comprehensive consideration the equilibrium time and decoloring rate of the Fe3O4-bentonite/H2O2 system, found that is better than Fe3O4, H2O2, Fe3O4/H2O2, magnetic bentonite systems. The best process conditions determined by single factor experiments are as follows:the initial pH was 3, Fe3O4-bentonite dosage was 0.5 g·L-1, the amount of H2O2 was 0.05 mol·L-1, the initial concentration of MO was 100 mg·L-1, the reaction temperature was 40℃, the decolorization rate of MO was highest. Due to the special structure of MO, the range of pH has no obvious widen. After 5 times repeated use by Fe3O4-bentonite, the decolorization rate remains as high as 89.94%. And the quantity of iron ion dissolution compared with Fe3O4-bentonite addition amount can be negligible, as it was only 3.23×10-3 mg·L-1 after 60 min reaction, which illustrating that Fe3O4-bentonite has good catalytic activity and higher service life.The results of the second part experimental:The best reaction conditions of Ch-Fe2+/H2O2 system catalytic degradation of MB determined by the single factor experiment are as follows:the dosage of Ch-Fe2+and H2O2 was 10000 mg·L-1 and 1200 mg·L-1, the initial concentration of MB was 120 mg-L"1, initial pH=7, the reaction temperature was 30℃, the decolorazation rate of MB was 99.96%. Compared with the homogeneous Fenton, pH scope between 3 to 7 was significantly widened. Through dynamics research found that the heterogeneous Fenton system follows the first order kinetics model. The UV-vis spectra and COD show that MB is not entirely oxidated into CO2 and H2O in the process of degradation, but generated intermediate products. After 5 times repeated use by Ch-Fe2+, the decolorization rate remains as high as 90%. And the quantity of iron ion dissolution was only 6.16×10-3 mg·L-1 after 120 min reaction, which illustrating that Ch-Fe2+ has a high stability and good catalytic activity.