This study applied sputtering technology to prepare composite film photocatalyst TiO2/ITO for investigating the decomposition efficiency of acetone using composite TiO2/ITO made by single- and multi-layer processes. The influences of operating parameters, including sputtering operating parameters and photocatalytic operating parameters, on the decomposition efficiency of acetone were further investigated. Operating parameters investigated for the sputtering process included oxygen to argon ratio (O2/Ar), temperature, substrate, sputtering dutation, and sputtering layers, while operating parameters investigated for the photocatalytic decomposition of acetone included light wavelength, H2O concentration, O2 concentration, initial acetone concentration, and the type of photocatalysts. In the experiments, acetone was degraded by the composite film photocatalyst TiO2/ITO in a self-designed batch photocatalytic reactor. Operating parameters included light wavelength (350~400 nm, 435~500 nm, 506~600 nm), the type of photocatalysts (single-layer film photocatalyst TiO2/ITO with the thickness of 355.3, 396.6, 437.5, 487.5, and 637.5 nm; double- and triple-layer TiO2/ITO), H2O concentration (0, 50, 100, 200, and 300 ppm). The incident light with different wavelength irradiated with three 15-W lamps of near UV light or LED lamps of blue and green lights placed on the top of the photocatalytic reactor. Acetone was injected into the reactor by using a gasket syringe and vaporized for further photocatalytic degradation on the film photocatalyst TiO2/ITO placed at the bottom of the reactor. Air samples were taken to analyze acetone concentration with a GC/FID. The composite film photocatalyst TiO2/ITO was mainly composed of anatase with a few rutile. The thicknesses of the single- and IV double-layer film photocatalyst with the thickness of 473.5 nm and 506.0 nm, respectively. Experimental results indicated that the highest decomposition efficiency of acetone was obtained by using TiO2/ITO, followed by TiO2/ground glass and TiO2/glass. The highest decomposition efficiency of acetone was observed by using TiO2/ITO at 50¢XC, 20% O2, and 100 ppm H2O. In the kinetic model, the acetone decomposition of single-layer TiO2/ITO was zero-order reaction. The acetone decomposition of double-layer TiO2/ITO in high initial acetone concentration was zero-order reaction, while that in low initial acetone concentration was first-order reaction. Thus, the decomposition of acetone exerted by TiO2 film photocatalyst can be enhanced efficiently by ITO. Under the incidence of blue light, the reaction rate of acetone decomposition were 2.353¡Ñ10-5 and 3.478¡Ñ10-5 £gmole/cm2-s for using single- and double-layer TiO2/ITO, respectively. Finally, a bimolecular Langmuir-Hinshelwood (L-H) kinetic model was applied to simulate the influences of initial acetone concentration, temperature, and relative humidity on the promotion and inhibition for the photocatalytic degradation of acetone. This study revealed that the L-H kinetic model could successfully simulate the photocatalytic reaction rate of acetone.

The study combined photoelectrocatalytic technology (PEC) with electrical glassfiber filter (EGF) to decompose volatile organic compounds (VOCs). External electrical voltage was applied to retard the recombination of electron-electron hole pairs and increase the surface temperature of the photocatalysts coated on the electrical glassfiber filter, which could further decompose VOCs more effectively via photoelectrocatalytic technology. Acetone was selected as the gasous pollutant for this particular study. A commercial TiO2 photocatalyst (AG-160) was coated on GFF via impregnation to decompose acetone in a batch PEC reactor. Operation parameters investigated in this study included acetone concentration (50~400 ppm), electrical voltage (0~6,500V), water content (0~20,000 ppm), reaction temperature (40¢J~80¢J).The incident UV light of 365 nm wavelength was irradiated by three 15-wat low pressure mercury lamps (£f=365 nm) placing above the batch PEC reactor. The TiO2-coated EGF was placed at the center of the batch PEC reactor. Acetone was injected into the reactor by a gasket syringe to conduct the PEC decomposition test. Acetone was analyzed quantitatively by a gas chromatography with a flame ionization detector (GC/FID). Finally, a Langmuir-Hinshelwood kinetic (L-H) model was proposed to simulate the PEC reaction rate of acetone. Experimental results showed that the size range of the self-produced nano-sized photocatalyst prepared by sol-gel was 35~50 nm. Three duplicate tests of PC and PEC degradation of acetone indicated that TiO2 was not deactivated during the PC and PCE reactions, hence TiO2 can be reused in the experiments. Results obtained from the PC and PEC degradation experiments indicated that the PEC reaction rate was higher than the PC reaction rate.The PEC reaction rate increased with applied electrical voltage, and the highest decomposition efficiency occurred at 6,500 V. Electrical field generated by the differences of electrical voltage can effectively enhance the oxidation capability of TiO2 since electron (e-) can be conducted to retard the recombination of electron and electron hole pairs. Both PC and PEC technologies could be used to decompose acetone. Among them, PEC had highter decomposition efficiency of acetone than PC up to 34%. Rsults obtained from the operation parameter tests reaveled that raising electrical voltage could enhance the decomposition efficiency of acetone only for electrical voltages above 2,000 V. However, the decomposition efficiency of acetone tended to level off as electrical voltage became higher. Zero-order reaction rate of the PEC reaction was observed for initial acetone concentration of 100~400 ppm, while the PEC reaction decreased gradually for initial acetone concentration reaction below 100 ppm. It revealed that the PEC reaction was pseudo ozero-order for initial acetone concentration of 100~400 ppm, and pseudo first-order reaction for acetone concentration below 100 ppm. Additionally, the PC reaction rate increased with temperature at 45-80¢J. However the PEC reaction rate increased with temperature at 45-60¢J, and decreased with temperature at 60-80¢J. An adsorptive competition between acetone and water molecules at the active sites over TiO2 surface caused either promotion or inhibition of TiO2 decomposition depending on moisture content . For the PC and PEC reactions, the optimum operating condition of water vapor concentration was 10,000 ppm, but inhibition occurred when the water vapor concentration increased up to 20,000 ppm. Finally, the Langmuir-Hinshelwood kinetic model was applied to investiage the influences of reaction temperature, initial concentration of acetone, and water content on the photoelectrocatalytic reaction rate of acetone. Model simulation results showed that photoelectrocatalytic reaction rate constant of acetone(kLH) and adsorptive equilibrium constant(KA) increased with electrical voltage and acetone initial concentration. This study sevealed that experimental and simulated results were in good agreement. Thus, PEC reaction rate of acetone on the surface of TiO2 can be also succesfully simulated by the L-H kinetic model.

Recently, restaurant employees exposing to cooking oil fume with potential lung cancer was highly concerned, indicating cooking oil fume emitted from restaurants might cause tremendous hazard to human health. This study combined photocatalytic oxidation and ozone oxidation technology to decompose VOCs from the exhaust of cooking oil fume from restaurants. Firstly, this study selected three different types of restaurants to implement air pollutant measurements in the indoor dinning room and stack emission. Indoor TVOCs continuous monitoring data showed that the highest TVOCs concentration was generally observed in the dining peak time. In this study, photocatalyst coated fiberglass filter was prepared by impregnation procedure and its characteristics was analyzed by SEM and XRD. Experimental results showed that the particle size of photocatalyst ranged from 25 to 50 nm and had high percentage of Anatase, suggesting that it had high photocatalytic reactivity. This study designed a continuous-flow reaction system combined nano-sized TiO2 photocatalysis with ozone oxidation technology to decompose VOCs from cooking oil fume. After passing through a fiberglass filter to remove oil droplets, the cooking oil fume then coated with nano-sized titanium oxide (UV/TiO2) fiberglass filter purification system, and then injected ozone into the system to decompose residual VOCs. This study further investigated the influences of operating parameters, including TVOCs initial concentration, O3 injection concentration, and reaction temperature on the decomposition efficiency of TVOCs by using the UV/TiO2/O3 technology. When the photocatalytic reaction temperature was 35~50¢J, the TVOC decomposition efficiency slightly increased with reaction temperature, however, when the reaction temperature went up to 55¢J, the TVOC decomposition efficiency increased only slightly, but did not increased linearly. Combination of photocatalysis and ozone oxidation system performance test results showed that ozone could decompose approximately 34% VOCs, and followed by the photocatalytical reaction of residual pollutants, achieving an overall decomposition efficiency of about 75%; while photocatalytic reaction can remove 64% of TVOCs and followed by O3 for the decomposition of residual pollutants, achieving an overall decomposition efficiency up to 94%. It showed that the combined UV/TiO2+O3 system could effectively remove VOCs in the cooking oil fume from the exhaust of restaurants. By using GC/MS to qualitatively analyze the speciation of TVOCs from cooking oil fume before and after UV/TiO2/O3, the results showed that the composition of VOCs had a decreasing trend. The peak area and dilution factor were applied to estimate the decomposition efficiency of different VOCs species. The decomposition efficiencies of pentane, 2-acrolein, acrolein, heptane, pentanal, hexanal, 2-hexenal, heptanal, heptenal and ethylhexenal were 56.21%, 72.88%, 51.33%, 32.23%, 59.04%, 69.22%, 73.53%, 41.37%, 92.57%, and 96.02%. Finally, a Langmuir-Hinshelwood kinetic model was applied to simulate the photocatalytic decomposition efficiency with the initial concentration of cooking oil fume. Model simulation results showed that the reaction rate increased with the initial TVOCs concentration. However, when TVOCs concentration increased gradually, the reaction rate became constant since the activated sites on the photocatalyst¡¦s surface was limited and cannot allow more VOC molecules diffuse to the activated sites for further photocatalytic reaction.