Study On Oxidative Degradation Of DMF In Wastewater Using Heterogeneous Fenton Catalyst

N,N-dimethylformamide (DMF) is an excellent solvent and organic synthesis material for industry, and it is widely used in industries like leather, chemical, pharmaceutical and pesticide as well. Wastewater containing DMF shows low biodegradability, high toxicity and stability, which is harm to human health and environment. DMF in wastewater with high concentration is mainly recycled; while that with low concentration is removed by degradation. Most methods of treating DMF wastewater with low concentration still exist shortages, such as low removal efficiency, complex process, high cost. However, it is necessary to develop a new technology treating DMF in wastewater with low cost and simple operation.This thesis studies oxidative degradation of DMF in wastewater using heterogeneous Fenton technology. It focuses on oxidative degradation process for DMF using powder activated carbon supported iron (Fe/C) catalyst. Details are as follows:The first chapter is the literature review which summarized various technologies for treatment of wastewater containing DMF and the development of Fenton oxidative technology including homogeneous and heterogeneous technology.The second chapter summarizes the experimental materials, the use of laboratory equipments, as well as catalyst preparation method and experimental methods. The analytical methods of mensurating COD, iron content and H2O2content respectively in solution are introduced in detail.The third chapter is about experimental study of heterogeneous Fenton catalysts for removal of DMF in wastewater. Fe/C1,Fe/C2, Fe/MMT, Fe/Zeolite and Fe/ZSM-5catalysts were prepared by impregnation method using different supports, including powder actived carbon, active carbon particles, montmorillonite, artificial zeolites and ZSM-5zeolites respectively. The effect of adsorption and catalytic oxidation of these catalysts on COD removal rate for DMF wastewater was studied and compared. Fe/C catalyst with powder actived carbon was selected as the best catalyst to treat DMF wastewater。The adsorbability, catalytic performance and stability of Fe/C catalyst were further investigated.The fourth chapter is using Fe/C catalyst to treat DMF wastewater and investigating the effect of initial pH value, H2O2dosage, catalyst dosage and reaction temperature on COD removal rate for batch reaction. Under the optimal process conditions, for1000mg/L DMF solution, the COD removal rate was more than60%in60min, and iron leaching concentration in solution was very low. Reaction kinetics were studied preliminarily. It turned out this DMF degradation reaction obeys a second order reaction kinetics.The fifth chapter makes a study of DMF oxidative degradation in continuous reaction, based on optimum conditions of batch reaction. The effect of feed flow rate and catalyst dosage on COD removal rate was studied. Under the optimal conditions, COD removal rate was above50%in12h and iron leaching concentration is particularly low.The sixth chapter summarizes the main contents of this article and gives some suggestions on the research and development of the oxidative degradation of DMF using Fe/C heterogeneous Fenton catalyst.