Research On Synthesis Of Iron Oxide Supported On Titania Catalysts And Their Catalytic Properties For The Decomposition Of1,2-dichlorobenzene

Presently, Incineration is the most effective method to deal with industrial, municipaland medical wastes, Chlorinated volatile organic compounds （Cl-CVOCs） are produced fromthe combustion processes. Among the Chlorinated volatile organic compounds,Polychlorinated dibenzodioxins and dibenzo-furans （PCDDs and PCDFs）, also nameddioxins, and polychlorinated biphenyl are very toxic, persistent, and accumulated in theorganism, seriously endanger the health of human and animals. The control technology andcatalytic oxidation reaction mechanism of Cl-CVOCs have been the focus on environmentalchemistry. Catalytic oxidation has been proved to be the most appropriate solution because itallows to directly decompose these pollutants at low temperature with excellent selectivitytowards harmless products. Since the Transitional metal oxides show high catalytic activityand isn’t easily deactivated, they have been a class of widely used catalysts in lots ofapplications. Researchers at home and abroad have carried out large amounts of study onpreparing highly active, economic and environmental friendly catalysts of transitional mentaloxides, also discussing the catalytic reaction mechanism.In the dissertation, series of Ca-doping iron oxide catalysts supported titania catalystswere prepared, and their catalytic properties for the catalytic oxidation of o–dichlorobenzene（o–DCB, as the model compound of polychlorinated aromatic pollutants） were studied. Wediscussed the influence of the roasting temperature, the load of mental oxides, Ca-doping andthe fraction of water vapor in the reaction system. The main research contents andconclusions can be summarized as follows:1、Cationic surfactant-CTAB employed to prepare porous titania of high-surface area.co-precipitation method was prepared catalysts for the first time, which use prepared titaniaas support. The prepared catalyst samples were characterized by Flame Atomic AbsorptionSpectrometry（FAAS）, Inductively Coupled Plasma-Atomic Emission Spectrometry（ICP-AES）, X-ray diffraction（XRD）, Scanning electron microscope（SEM）,N₂absorption-desorption.The results indicate that the titania and iron species in the catalystsexisted as anatase and α–Fe₂O₃renspectively, with average crystalline size in the range of20²5nm. Their catalytic behavior and influence factors for o–DCB catalytic oxidation werestudied using a fixed bed micro actor-GC system. The results of catalytic activitymeasurements showed that600℃was the best Roasting Temperature, maintaining4h; Thecalcium-doping iron oxide supported titania catalyst with calcium and iron contents of12%, show the highest activity for degradation o-DCB; A synergistic effect of calcium and ironactive components, which effectively improved the activity for degradation o-DCB; thestability of the catalyst was inferior to it’s reproducibility.2、Macro-mesoporous titania was prepared by a simple approach of sulphation with theuse of sulfuric acid solution（pH=2），which has more higher-surface area. Macro-mesoporousiron oxide supported titania nano catalysts were prepared by precipitation method. Aftercharacterizing the prepared catalyst samples, the influence of some parameters of the roastingtemperature,the loading of supported iron contents, and the fraction of water vapor in thereaction system for the degradation of o-DCB were investigated. The results indicated:300℃was the best Roasting Temperature; The iron oxide supported titania catalyst with ironcontents of10%, show the highest activity for degradation o-DCB; the content of water vaporin the reaction system has complex effect on catalytic activity, lower water vapor contentcould improve the activity of catalysts, but the activity decrease with increasing H2Oconcentration, and also is non-beneficial to the absorption of pollutant.