Controlled Preparation Of Nano Fe₂O₃ And Its Photo-degradation Properties For Dibutyl Phthalate （DBP）

Recently, the growingly intense environmental pollution, especially the industrial wastewater has been attracting much attention. As a kind of environmental toxic organic pollutants, the phthalate ester compounds in industrial wastewater may interfere with the body’s endocrine system, resulting in great harm to human. The photocatalysis, which could directly employ solar energy to degrade the organic contaminants into simple inorganic matters, further mineralize them into H2O and CO2, is regarded as an ideal environment treatment technology. It was studied that, Fe2O3 nanomaterials could display comparatively high degradation activity for organic pollutants under the light irradiation. In the dissertation, Fe2O3 nanomaterials with different morphologies were controlled synthesized, and their activities in the photo-degradation of dibutyl phthalate (DBP) were systematically studied.In this dissertation, hollow, sheet-like, burger-like, shuttle-like, and walnut-like Fe2O3 nanoparticles were synthesized by adjusting experimental conditions such as the additive agent in the hydrothermal process. All the prepared samples were characterized by using XRD, FT-IR, SEM and TGA. The result shows that, the particles of Fe2O3 are at nanometer level and alpha crystal type, and they are with high crystallinity and good dispersion. Among them, the different surfactants exhibited different surface energy, play a different role in the crystal growth process, thereby regulating the morphology and size of nano Fe2O3.The photo-degradation experiments based on these Fe2O3 nanostructured materials were carried out by using UV as the light source and H2O2 as the promoter. The optimal parameters and mechanism of degradation were investigated by changing the morphology and usage amount of catalysts, the dosage of H2O2, pH value, and the initial concentration of DBP and so on. As revealed, hollow Fe2O3 nanoparticles showed the highest degradation efficiency when 30 mg catalyst and 50 uL H2O2 were used in the DBP solution with the initial concentration of 13 mg/L at pH= 6.5, when the reaction to 90min, DBP has degraded 93%. The mechanism of photocatalytic degradation of DBP was studied by GC-MS technique. The result shows that, the main intermediate in DBP degradation were otho-phthalate monobutyl ester and methyl benzoic acid, benzoic acid, benzaldehyde, heptyl aldehyde, when the reaction was to 2h. DBP and their intermediate are almost fully degraded, when it was to 12h. It turns that, DBP can be fully degraded to CO2 and H2O by extended time in the system of /H2O2/UV photocatalytic degradation.