Study On The Preparation Of Composite Iron Oxide Hollow Microspheres And Their Properties For Catalytic Oxidation Of Chlorinated Aromatic Hydrocarbons

Chlorinated aromatic hydrocarbons, which with high toxicity, persistence and bioaccumulation, have seriously endangered human health and damaged the ecosystem. It has aroused wide attention from scholars in the world, and become a global environmental problem. Catalytic oxidation Is considered to be the most promising and effective means to remove chlorinated aromatic hydrocarbon pollutants, because it can directly destroy theses pollutants from the emission sources and form harmless products. The transition metal oxides which is the widely used catalysts, also has an important value in catalytic degradation of chlorinated aromatic pollutants. To design and prepare highly catalytic active, environmental friendly, cheap and readily available catalysts, Researchers have carried out large amount of work and discussed the catalytic reaction mechanism. Hollow microspheres have became a hot spot in the field of materials science and has broad application prospects for its unique structure. The focus of future research content are developing hollow microspheres of composite transition metal oxides and controlling the composition, the size and so on.In the dissertation, we prepared series of composite iron oxide hollow microspheres and studied their catalytic properties for the catalytic oxidation of o-dichlorobenzene (o-DCB, as the model compound of aromatic hydrocarbons pollutants). The catalysts were characterized by SEM, TEM, XRD, XPS and so on. The influence of calcination temperature, catalyst composition, content of oxygen, water on catalytic activity was studied and the catalytic reaction mechanism was also preliminary discussed. Structure-activity relationship has been studied preliminarily.The iron oxide hollow microspheres and composite iron calcium oxide hollow microspheres with different active ingredient and mesoporous structure were prepared in the presence of the carbon microspheres as a template. XRD analysis indicated that average crystalline size in the range of21.4-40.0nm. Nitrogen adsorption/desorption analysis indicated that the mesoporous average pore diameter, specific surface area, total pore volume of Fe7.sCa6were16.1nm,78.7m2/g and0.61cm3/g, respectively. The o-DCB could be completely catalytic oxidation over these hollow microspheres at350-400℃, and calcination temperature, the molar ratio of iron and calcium in the hollow microspheres, the water and O2content in reaction atmosphere were very important for the catalytic activity. The activation energy of Fe2O3and Fe7.5Ca6hollow microspheres were28.5KJ/mol and21.6KJ/mol, respectively.The composite iron manganese oxide hollow microspheres with different active components were prepared using carbon microspheres as a template. The o-DCB could be completely catalytic oxidation over these hollow microspheres at350-400℃, and calcination temperature, the molar ratio of iron and calcium in the hollow microspheres, the water and O2content in reaction atmosphere were very important for the catalytic activity. The FeMn30hollow sphere overall exhibited the highest activity, and presented good catalytic stability.