published_or_final_version / abstract / Mechanical Engineering / Master / Master of Philosophy

by Yuk-Lin Chan. / Thesis (M.Phil.)--Chinese University of Hong Kong, 1999. / Includes bibliographical references (leaves 78-83). / Abstracts in English and Chinese. / Abstract (English version) --- p.i / Abstract (Chinese version) --- p.ii / Acknowledgments --- p.iii / Table of Contents --- p.iv / List of Figures --- p.vi / List of Tables --- p.vii / Chapter 1. --- Introduction / Chapter 1.1 --- Indoor Air Pollution --- p.1 / Chapter 1.2 --- Typical Treatment of Air Pollutant --- p.6 / Chapter 1.3 --- Photocatalytic Degradation over Titanium Dioxide --- p.7 / Chapter 1.4 --- Advantages of Titanium Dioxide as a Photocatalyst --- p.12 / Chapter 1.5 --- Applications of Photocatalytic Degradation in Pollution Control --- p.14 / Chapter 1.5.1 --- Aqueous Phase Decontamination --- p.15 / Chapter 1.5.2 --- Gas Phase Decontamination --- p.15 / Chapter 1.6 --- Development of the Photocatalytic Degradation Technique --- p.16 / Chapter 1.6.1 --- Pure Ti02 --- p.17 / Chapter 1.6.2 --- Design of the Reactors --- p.18 / Chapter 1.6.3 --- Metal Ion Dopants --- p.21 / Chapter 1.6.4 --- Mixture with Supports --- p.21 / Chapter 1.7 --- Adsorbent-Supported Titanium Dioxide --- p.22 / Chapter 1.7.1 --- Use of Adsorbents other than Zeolites --- p.22 / Chapter 1.7.2 --- Use of Zeolites --- p.25 / Chapter 1.8 --- Molecular Sieves --- p.29 / Chapter 2. --- Experimental / Chapter 2.1 --- Block diagram of the Reaction Setup --- p.31 / Chapter 2.2 --- Fixed Volume Batch Reactor --- p.32 / Chapter 2.3 --- Reagents --- p.34 / Chapter 2.3.1 --- Degussa P25 Ti02 powder --- p.34 / Chapter 2.3.2 --- Aldrich Molecular Sieves (Organophilic) --- p.35 / Chapter 2.3.3 --- Other Adsorbents Used for Comparison --- p.35 / Chapter 2.4 --- Instrumental Analysis --- p.36 / Chapter 2.4.1 --- Photoacoustic Multi-gas Monitor --- p.36 / Chapter 2.4.2 --- X-Ray Diffraction Analysis --- p.42 / Chapter 2.4.3 --- Scanning Electron Microscopy --- p.42 / Chapter 2.4.4 --- UV-vis Diffuse Reflectance Spectroscopy --- p.42 / Chapter 2.4.5 --- Iso-electron Point Measurements --- p.43 / Chapter 2.5 --- Photocatalytic Degradation of Simple Alkanes by P25 Titanium Dioxide --- p.45 / Chapter 2.6 --- Photocatalytic Degradation of Gaseous Acetone over Organophilic Molecular Sieves-Supported Titanium Dioxide --- p.49 / Chapter 3. --- Results and Discussion / Chapter 3.1 --- Photocatalytic Degradation of Simple Alkanes by P25 Titanium Dioxide --- p.52 / Chapter 3.1.1 --- Rate of Photocatalytic Degradation of Simple Alkanes --- p.52 / Chapter 3.1.2 --- Summary of Rate of Photocatalytic Degradation of Simple Alkanes --- p.57 / Chapter 3.2 --- Photocatalytic Degradation of Gaseous Acetone over Organophilic Molecular Sieves-Supported Titanium Dioxide --- p.58 / Chapter 3.2.1 --- The Adsorption Ability of Various Adsorbents --- p.58 / Chapter 3.2.2 --- XRD Pattern Measurement --- p.60 / Chapter 3.2.3 --- Scanning Electron Microscopy --- p.64 / Chapter 3.2.4 --- UV-vis Diffuse Reflectance Spectroscopy --- p.65 / Chapter 3.2.5 --- Iso-electron Point Measurements --- p.67 / Chapter 3.2.6 --- Photocatalytic Activity of Various Catalysts --- p.69 / Chapter 4. --- Conclusion --- p.76 / Bibliography --- p.78 / Appendix / "A Demonstration of Photocatalytic Degradation by Gaseous Organic Pollutant, Dichloromethane " --- p.83

by Hei Yuk Kwan. / Thesis (M.Phil.)--Chinese University of Hong Kong, 1999. / Includes bibliographical references (leaves 81-87). / Abstract also in Chinese. / ABSTRACT --- p.i / DECLARATION --- p.ii / ACKNOWLEDGEMENT --- p.iii / TABLE OF CONTENTS --- p.iv / LIST OF TABLES --- p.vi / LIST OF FIGURES --- p.vii / Chapter CHAPTER ONE : --- INTRODUCTION --- p.1 / Chapter 1.1 --- Background --- p.1 / Chapter 1.1.1. --- Volatile Organic Compounds --- p.1 / Chapter 1.1.2. --- Photocatalytic Oxidation --- p.2 / Chapter 1.1.3. --- Adsorption --- p.4 / Chapter 1.2. --- Scope of Work --- p.8 / Chapter CHAPTER TWO : --- PHOTOCATALYSIS --- p.10 / Chapter 2.1 --- Fundamental --- p.10 / Chapter 2.2. --- Experimental --- p.14 / Chapter 2.2.1. --- Materials --- p.14 / Chapter 2.2.2. --- Instruments --- p.14 / Chapter 2.2.3. --- Experimental Conditions --- p.19 / Chapter 2.2.4. --- Procedure --- p.20 / Chapter 2.3. --- Results and Discussion --- p.28 / Chapter 2.3.1. --- Photocatalytic Degradation of DCE --- p.28 / Chapter 2.3.2. --- Photocatalytic Degradation of TCE --- p.31 / Chapter 2.3.3. --- Photocatalytic Degradation of DCE and TCE Binary System --- p.34 / Chapter 2.3.4. --- Photocatalytic Degradation of Ethyl Acetate --- p.39 / Chapter 2.3.5. --- Photocatalytic Degradation of Methyl Isopropyl Ketone --- p.41 / Chapter 2.3.6. --- Photocatalytic Degradation of Ethyl Acetate and Methyl Isopropyl Ketone Binary System --- p.43 / Chapter CHAPTER THREE : --- ADSORPTION --- p.47 / Chapter 3.1. --- Fundamental --- p.47 / Chapter 3.1.1. --- Mordenite --- p.51 / Chapter 3.1.2. --- Activated Carbon --- p.55 / Chapter 3.2. --- Experimental --- p.58 / Chapter 3.2.1. --- Materials --- p.58 / Chapter 3.2.2. --- Instrument --- p.59 / Chapter 3.2.3. --- Procedure --- p.60 / Chapter 3.3. --- Results and Discussion --- p.65 / Chapter 3.4. --- "Adsorption Isotherm of 1,3,5-trimethylbenzene on Mordenite in Aqueous Phase" --- p.70 / Chapter 3.5. --- "Thermal Regeneration of 1,3,5-trimethylbenzene on Mordenite in Aqueous Phase" --- p.72 / Chapter CHAPTER FOUR : --- CONCLUSION --- p.79 / REFERENCES --- p.81

Experiments were conducted to determine the photocatalytic degradation of three types of gas-phase compounds, NOX, VOCs, and chloramines, by TiO2 impregnated tiles. The oxides of nitrogen NO and NO2 (NOx) have a variety of negative impacts on human and environmental health ranging from serving as key precursors for the respiratory irritant ozone, to forming nitric acid, which is a primary component of acid rain. A flow tube reactor was designed for the experiments that allowed the UV illumination of the tiles under exposure to both NO and NO2 concentrations in simulated ambient air. The reactor was also used to assess NOx degradation for sampled ambient air. The PV values for NO and NO2 were 0.016 cm s-1 and 0.0015 cm s-1, respectively. For ambient experiments a decrease in ambient NOx of ~ 40% was observed over a period of roughly 5 days. The mean PV for NOx for ambient air was 0.016 cm s-1 and the maximum PV was .038 cm s-1. Overall, the results indicate that laboratory conditions generally simulate the efficiency of removing NOx by TiO2 impregnated tiles. Volatile organic compounds (VOC's) are formed in a variety of indoor environments, and can lead to respiratory problems (US EPA, 2010). The experiments determined the photocatalytic degradation of formaldehyde and methanol, two common VOCs, by TiO2 impregnated tiles. The same flow tube reactor used for the previous NOX experiments was used to test a standardized gas-phase concentration of formaldehyde and methanol. The extended UV illumination of the tiles resulted in a 50 % reduction in formaldehyde, and a 68% reduction in methanol. The deposition velocities (or the photocatalytic velocities, PV) were estimated for both VOC's. The PV for formaldehyde was 0.021 cm s-1, and the PV for methanol was 0.026 cm s-1. These PV values are slightly higher than the mean value determined for NO from the previous experiments which was 0.016 cm s-1. The results suggest that the TiO2 tiles could effectively reduce specific VOC levels in indoor environments. Chlorination is a widespread form of water disinfection. However, chlorine can produce unwanted disinfection byproducts when chlorine reacts with nitrogen containing compounds or other organics. The reaction of chlorine with ammonia produces one of three chloramines, (mono-, di-, and tri-chloramine). The production of chloramines compounds in indoor areas increases the likelihood of asthma in pool professionals, competitive swimmers, and children that frequently bath in indoor chlorinated swimming pools (Jacobs, 2007; Nemery, 2002; Zwiener, 2007). A modified flow tube reactor in conjunction with a standardized solution of monochloramine, NH2Cl, determined the photocatalytic reactions over the TiO2 tiles and seven concrete samples. The concrete samples included five different concrete types, and contained either 5 % or 15 % TiO2 by weight. The PV for the tiles was 0.045 cm s-1 for the tiles manufactured by TOTO Inc. The highest PV from the concrete samples was 0.054 cm s-1. Overall the commercial tiles were most efficient at reducing NH2Cl, compared to NOX and VOC compounds. However, the concrete samples had an even higher PV for NH2Cl than the tiles. The reason for this is unknown; however, distinct surface characteristics and a higher concentration of TiO2 in the concrete may have contributed to these findings.