| Summary: | 碩士 === 國立臺灣大學 === 生物產業機電工程學研究所 === 104 === People stay indoor most of the time, optimizing the indoor air quality become more important. The purposes of this study are to investigate the photodegradation efficiency of TiO2 P25, TiO2 mixed active carbon and MTA in four photocatalytic reactors. Using CFD modeling to observe the air flow inside the cyclone and optimizing the structure to increase the opportunity of the pollutant to touch photocatalyst. Developing an air cleaner for photodegradation of VOCs, particulate matter captured and disinfection.
The results show that the photodegradation rate of acetone in photocatalytic reactor l by using TiO2 P25, TiO2 mixed active carbon and MTA as photocatalyst are 2.3 × 10-3, 0.5 × 10-3, 6.7 × 10-3 , respectively. While, the photocatalytic reactor 2 in 725 L test chamber are 0.8099、0.7950、0.8357 ppm, respectively and for the photocatalytic reactor 3 are 0.8093、0.7544、0.9484 . Comparison the photodegradation rate of mixing 1, 2, 3g active carbon. The result shows that the photodegradation rate of using TiO2 mixed 3g actived carbon is the best.
Cyclone photocatalytic reactor has the best photodegradation efficiency. The photodegradation rate of acetone in photocatalytic reactor 4 and 3 are 18.9 × 10-3 ppm and 83.1 × 10-3 , respectively. The concentration of ammonia in photocatalytic reactor 4 after UV-irradiation for 7hr decreases from 8.8 ppm to 0.1114 ppm. The cyclone photocatalytic reactor has high photodegradation efficiency of HCHO. The concentration of HCHO decreases from 3.257 ppm to 0.013 ppm after UV-irradiation for 160 min. For simulate a real situation of polluted environment, the initial concentration of HCHO has been controlled at 0.111ppm. The concentration of HCHO attained to a value of 0.072 ppm in 4 min. In addition, active carbon can adsorb the side products that are generated from the photocatalytic process.
In regeneration experiment, 1g of photocatalyst after UV-irradiation for 2hr, the capability of photodegrade has been improved and UV-irradiation for 4hr has the best result. The UV lamps in this study won’t decay significantly after turn on 72hr. The intensity before 72hr is 4.02mWcm-2, after turn on for 72hr the intensity becomes to 4.00 mWcm-2. Four UV lamps are inserted inside the cyclone. After UV-irradiation, E.coli has a zero survival rate.
In kinetic analysis, the reaction rate of photocatalyst coating area is half and full are 3.5 × 10-4
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