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Gas-Phase Photocatalytic Oxidation of Volatile Organic Compounds with Fluidized-Bed Optical Fibers Reactor

Author: XuGuiLin
Tutor: ZhuRongShu
School: Harbin Institute of Technology
Course: Environmental Science and Engineering
Keywords: Photocatalytic reactor Fiber source Fluidized bed Photocatalyst VOCs
CLC: X701
Type: Master's thesis
Year: 2010
Downloads: 52
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Abstract

In recent years the use of the TiO ₂ light catalytic performance to remove volatile organic compounds in the air becoming photocatalytic hot. Photocatalytic reactor design is one of the key factors to improve the photocatalytic efficiency. Present extensive study of fixed-bed existence of mass transfer and optical transmission restricted light use efficiency and low; existing fluidized bed photocatalytic reactor in the presence of light transmission uneven. The topics to fiber to transmit light and uniform arrangement of the light source, combined with fluidized bed high mass transfer efficiency advantages, self-designed gas - solid fluidized bed - fiber photocatalytic reactor for volatile organic compounds (VOCs) light catalytic degradation. The study should include: (1) fluidized bed - Fibre photocatalytic reaction device optimization. By adjusting the particle size distribution of the catalyst and the reaction gas flow rate to optimize the flow of the fluidized bed state. Determine the optimum parameters for the fluidized bed: photocatalyst particle diameter of 60 to 120 mesh, the mass range of 1.00 g to 1.01 g, 60 ~ 80 mesh 80 ~ 100 mesh, 100 to 120 mesh catalyst mass ratio of 1:2 : 2; fluidized bed static bed height of approximately 27mm, 106mL/min hours when the total flow of the reaction gas, the fluidized-bed-storey approximately 36mm, preferably fluidization state. Photocatalyst SEM and BET characterization results to determine the 10% TiO ₂ / SiO ₂ photocatalytic degradation experiments. (2) to mark the optical fiber 138 as the object to be measured, adjusting the output light quantity of the UV light source, potassium iron oxalate method with UV-B irradiation was measured light intensity of the optical fiber. The light intensity of the measurement results: light source light quantity of the UV lamp and the the fiber light intensity measured under the conditions of the corresponding light source light quantity substantially linearly. From the fiber optic hair the bald 10mm, potassium ferric oxalate method for the determination of the optical fiber 138 light intensity and irradiation was measured light intensity values ??correspond to a linear relationship. (3) under the optimum parameters in the fluidized bed, the target pollutants carried out using acetone as a fluidized bed - optic light catalytic reactor of degradation experiments to study the light intensity, the initial concentration of acetone to different groups of the catalyst loading and reaction gas stars influence of acetone photocatalytic degradation results showed that: in the light source light amount for 100%, the O ₂ content is 10% to 10% of the amount of the photocatalyst load conditions, the initial concentration of acetone was 150ppm when the photocatalytic degradation rate of 56.5%, optical quantum efficiency was 1.05%, the transforming activity of the catalyst unit weight 4.01μmol / (g catalyst · min); increase the amount of light the light source will increase the degradation rate of acetone. Increasing the initial concentration will reduce the rate of degradation of acetone. The degradation rate of acetone increases as the gas, the reaction O ₂ content increases, the the best O ₂ content of 10%; acetone degradation rate of the reaction gas with H ₂ O content increases first and then decreases H ₂ O content of 1%, acetone degradation rate of 66.6%. Acetone degradation rate increases with the increase in the amount of catalyst loading, the transforming activity of the catalyst unit is lowered with the increase in the amount of catalyst loading. (4) to trichlorethylene (TCE) as the target pollutants, examine the light intensity, the initial concentration of TCE, reaction the the gas O ₂ content and H ₂ O content photocatalytic degradation of TCE. The results show that: under the condition of light source light amount for 100%, the O ₂ content is 10%, 10% of the amount of photocatalyst, TCE initial concentration of 150ppm photocatalytic degradation rate of up to 68.2 %, the optical quantum efficiency was 1.27%, the transforming activity of the catalyst unit weight 4.84μmol / (g catalyst · min). Increases the amount of source light will increase the degradation rate of TCE. Increasing the initial concentration of TCE degradation rate will be reduced. TCE degradation rate increases with O ₂ content increases, the O ₂ content of 10%, 5% and 2.5%, the degradation of TCE effect difference large. TCE degradation rate with the reaction gas in the H ₂ O content increases first and then decreases H ₂ O content of 1% TCE degradation rate of 70.9%. (5) fixed bed - fiber photocatalytic reactor acetone, trichlorethylene photocatalytic degradation experiments, compared with the fluidized bed - fiber photocatalytic reactor. Light quantity of the light source, under the same conditions as the catalyst loading and reaction gas composition, a fluidized bed - Fibre photocatalytic reactor fixed bed - Fibre photocatalytic reactor having a higher removal of acetone and TCE, and having a higher light utilization efficiency and transforming activity of the catalyst.

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