| Summary: | 碩士 === 東海大學 === 環境科學與工程學系 === 103 === This study synthesized magnetic Fe3O4/SiO2/Pd-Mn catalysts in an ozonation system by the impregnation method. Catalysts were characterized using X-ray diffraction (XRD), scanning electron microscope (SEM) and Energy Dispersive Spectrometer (EDS). From the electron microscope image of the appearance of spherical catalyst particles was with diameter around 50-100 nm. The output of XRD and EDS showed that palladium and manganese were coated on the particle properly and the weight percent of palladium and manganese in the catalyst were 1.66% and 2.4%, respectively. It was used to decompose natural organic matters (NOMs) which were the water resource from central Taiwan, the Te-Chi reservoir. Heterogeneous catalytic ozonation in this study was investigated the degradation efficiency of DOC and A254. With the dose of 1 g/L of catalyst, the system can reach the decomposition of A254 and DOC to 70% and 60% respectively. While with the same dose under pH 11 case, the decay rate of A254 and DOC upgrade to 80% and 90% simultaneously. The first order reaction kinetic rates (kd = 6.5 10-2) indicated the catalyst can provide strong removal capability of NOMs compared to that reported in the literature. Coumarin is a scavenger in catalytic ozonation to capture free radical in solution. At pH 11, it has more efficient to decompose coumarin in the reactor, and k value obtained 6.0×10-2 min-1. The generation of by-product: 7-hydroxycoumarin had been indicated the effect of hydroxyl radical. At pH 11, the amount of 7-hydroxycoumarin had been generated mostly compared with other conditions of pH. The ratio of decomposition of THMFPs in catalytic ozonation had 74% more than 38% by sole ozonation. The recycle catalysts conduct the similar ozone test and can remain 80% removal efficiency. The experimental data (A254 and THMFP) are uesd to develop a modified Nernst type model for hetererogeneous catalytic ozonation. The results indicated Fe3O4/SiO2/Pd-Mn catalyst can effectively degrade natural organic matter.
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