Thesis (Ph. D.)--University of Wisconsin--Madison, 1932. / Typescript. Vita. With this is bound: The photolysis of gaseous acetone and the influence of water / By Glenn H. Damon and Farrington Daniels. Reprinted from Journal of the American Chemical Society, vol. 55 (1933), p. [2363]-2375. Includes bibliographical references (leaf [68]).

This study investigated the decomposition efficiency of acetone using unmodified (pure TiO2) and modified TiO2 (TiO2/ITO¡BTiO2/N) prepared by sputtering technology. The influence of operating parameters including wavelength and relative humidity on the decomposition efficiency of acetone was further discussed. Operating parameters investigated included light wavelength (350~400, 435~500, and 506~600 nm), photocatalysts (TiO2/ITO, TiO2/N, and TiO2), and relative humidity (RH) (0%, 50%, and 100%). In the experiments, acetone was degraded by photocatalysts in a self-designed batch photocatalytical reactor. Samples coated with TiO2 were placed in the batch reactor. The incident light with different wavelength was irradiated by a 20-watt lamp. Moreover, a low-pressure mercury lamp for UV light or LED lamps for blue and green lights were placed on the top of reactor. Acetone was injected into reactor by using a gasket syringe. Reactants and products were analyzed quantitatively by a gas chromatography with a flame ionization detector followed by a methaneizer (GC/FID-Methaneizer). The structure of the photocatalyst film surface showed taper and the width of column ranged from 100 to 200 nm. The film structure showed crystallization cylindrical surface and the thickness of the photocatalyst film was in the range of 4.0-4.3 £gm. The highest decomposition efficiency of acetone was observed by using TiO2/ITO under visible-light with 50% RH. The synthesis of TiO2 was mainly anatase for the tested photocatalysts. AFM images showed that the photocatalyst surface appeared rugged and the shape showed a mountain ridge distribution . Keywords: sputtering technology, modified photocatalysts, photosensitive, acetone, photocatalytic oxidation, acetone decomposition

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.

This study combined photocatalytic technology with activated carbon cellulose-paper filter (ACCF) adsorption to decompose gaseous pollutants. Gaseous pollutants were initially adsorbed by activated carbon and could be further decomposed by photocatalytic technology. This study selected acetone (CH3COCH3) as gaseous pollutants. Two market available photocatalysts (photocatalysts¢¹and¢º) were coated on ACCF by impregnation to decompose acetone in a batch photocatlytic reactor. Operating parameters investigated in this study included initial acetone concentration (4.1~10.2 £gM), reaction temperature (40~70¢J), and water vapor (0~20 %). The incident UV light of 365 nm was irradiated by a 20-watt low-pressure mercury lamp placing above the batch photocatalytic reactor. The ACCF coated with TiO2 was placed at the center of the photocatalytic reactor. Acetone was injected into the reactor by a gasket syringe to conduct the photocatalytic tests. Reactants and products were analyzed quantitatively by a gas chromatography with an electron capture detector (GC/DCD) and a flame ionization detector followed by a methaneizer (GC/FID-Methaneizer). Finally, a Langmiur-Hinshewood (L-H) kinetic model was proposed to describe the rate of photocatalytic reaction. Results obtained from the photocatalytic tests indicated that photocatalyst¢º was better than photocatalyst¢¹ for the decomposition of acetone. Experimental results indicated that the size range of self-produced TiO2 photocatalyst by sol-gel was 20~70 nm. The end products were mainly CO and CO2, which resulted in the mineralization ratio up to 98%. Results obtained from the operating parameter tests revealed that the increase of initial acetone concentration enhanced the amount of acetone adsorbed on ACCF, which however did not increase the reaction rate of acetone. Although the increase of reaction temperature could reduce the amount of acetone adsorbed on ACCF, the decomposition rate of acetone could be promoted, so as the yield rate and mineralization ratio of products (CO and CO2). The increase of water vapor could slightly decrease the amount of acetone adsorbed on ACCF. The competitive adsorption phenomenon between acetone and water molecules on active sites could decelerate the decomposion of acetone. Moreover, the ACCF would not be saturated since the adsorbed acetone could be further decomposed quickly by the photocatalysts, which made the TiO2/ACCF more effective on removing acetone and lasted longer than the conventional ACCF. Finally, a modified bimolecular Langmuir-Hinshelwood kinetic model was developed to investigate the influences of initial acetone concentration reaction, temperature, and relative humidity on the promotion and inhibition for the photocatalytic oxidation of acetone. The modified L-H kinetic model could successfully simulate the photocatalytic reaction rate of acetone. Thus, the reaction rate of acetone over TiO2/ACCF could be described by the modified L-H kinetic model.