Removing MTBE in water by using magnetic photocatalysts
Date Issued
2011
Date
2011
Author(s)
Shen, Chih-Hsiu
Abstract
The objective of this research was using Sol-Gel method to improve the conventional TiO2 catalysts. In order to increase the utility of visible light, ferroferric oxide and ammonium vanadate were composite of TiO2-Fe3O4 and V-TiO2 to provide the Rutile type structure, respectively.
Both TiO2-Fe3O4 and V-TiO2 catalysts treated by grinding and sieving, their average particle sizes were near 20 nm by SEM analysis. As shown in XRD results, Anatase type and Rutile type structures appeared in both TiO2-Fe3O4 and V-TiO2 catalysts before MTBE decomposition. Otherwise, the major 2θ values of TiO2-Fe3O4 appeared in 25.4（Anatase）, 36.2（Rutile）and 48.2（Anatase）, so it means Anatase type and Rutile type structures still existed after MTBE decomposition. Oppositely, one 2θ peak in 27.5 of V-TiO2 disappeared after MTBE decomposition, owing to Rutile type structures broken.
Observed the continuous discoloration experiments by composite TiO2-Fe3O4, the results of discoloration seemed to be not different in spite of three time reuses. Whether photocatalysts irradiated by Visible light or UV light, the performance of composite TiO2-Fe3O4 was rather than pure TiO2, and this also meant the durability of composite catalysts.
In the optimum doses experiment, it showed adding 5 g TiO2-Fe3O4 could achieve 91 % MTBE removals, and followed by the 10 g, 2 g and 1 g. Besides, V-TiO2 catalysts has 82 % MTBE removals, which atomic ratio of vanadium to TiO2 was 0.1 (0.10VT-I).
Continuous and close photoreactor systems were designed to degrade MTBE in this research. Under continuous system, pH10 was helpful for TiO2-Fe3O4 catalysts to gain better MTBE removals, but V-TiO2 photocatalytic degradation has better results under neutral pH 7. However, both V-TiO2 and TiO2-Fe3O4 have similar photocatalytic degradation results under close system whatever the pH value was pH 7 or pH 10.
Considered the material cost difference between Fe3O4 and NH4VO3, it should be adopted lower price first if their removals were very similar. Moreover, the Fe3O4 material has magnetism, so TiO2-Fe3O4 could be reused by external magnetic field while TiO2-Fe3O4 has more potential value in real.
Subjects
Sol-Gel method
methyl tert-butyl ether
visible light
Rutile type
Type
thesis
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