PERFORMANCE IMPROVEMENT OF TiO2 CATALYSTS SUPPORTED ON ADSORBENTS LI GANG NATIONAL UNIVERSITY OF SINGAPORE 2007 PERFORMANCE IMPROVEMENT OF TiO2 CATALYSTS SUPPORTED ON ADSORBENTS LI GANG (PhD, NUS) A THESIS SUBMITTED FOR THE DEGREE OF PhD OF ENGINEERING DEPARTMENT OF CHEMICAL AND BIOMOLECULAR ENGINEERING NATIONAL UNIVERSITY OF SINGAPORE 2007 Acknowledgement Acknowledgement I would like to convey my deepest appreciation to my supervisor, Assoc Prof Zhao X S., George for his constant encouragement, invaluable guidance, patience and understanding throughout the whole length of my PhD candidature This project had been a tough but enriching experience for me in research I would like to express my heartfelt thanks to A/P Dr Zhao for his guidance on writing scientific papers including PhD thesis I would also like to take this opportunity to acknowledge Prof M B Ray for her kindly advice and guidance during first years of my research work In addition, I want to express my sincerest appreciation to the Department of Chemical and Biomolecular Engineering for offering me the chance to study at NUS with a scholarship It’s my pleasure to work with a group of brilliant, warmhearted and lovely people, Dr Zhou Zuocheng, Dr Su Fabing, Dr Lv Lu, Dr Yan Qingfeng, Dr Zhou Jinkai, Mr Bao Xiaoying, Mr Wang Likui, Mr Bai Peng, Ms Lee Fang Yin, Ms Liu Jiajia, Ms Tian Xiaoning, Ms Zhang Lili, Ms Wu Pingping Particular acknowledgement goes to Mr Chia Phai Ann, Mr Shang Zhenhua, Dr Yuan Zeliang, Mr Mao Ning, Dr Rajarathnam D., Madam Chow Pek Jaslyn, Mdm Fam Hwee Koong Samantha, Ms Lee Chai Keng, Ms Tay Choon Yen, Mr Toh Keng Chee, Mr Chun See Chong, Ms Goh Siew Ping, Ms Ng Ai Mei, Ms Lum Mei Peng Sharon, and Ms How Yoke Leng Doris for their kind supports I thank my wife, Mo Huajuan, my daughter, parents, and brother It is no exaggeration to say that I could not complete the PhD work without their generous help, boundless love, encouragement and support i Table of Contents Table of Contents Summary………………………….………………………………………………… vii Nomenclature ………………………………………………………………… ix List of Tables …….…………………………………………………………… xi List of Figures………………………………………………………….………… xii CHAPTER INTRODUCTION………………………… ……….……….…1 1.1 Background… 1.2 Application of photocatalyst TiO2 in wastewater treatment…………… 1.3 Objectives of the project………………………………………….………….9 1.4 Structure of thesis…… ……………………………………………………10 CHAPTER LITERATURE REVIEW………………….…… ……….….12 2.1 Principles of semiconductor photocatalysis 12 2.1.1 Radiation source … 12 2.1.2 Mechanism of TiO2 photocatalyst………………………….… ……….15 2.1.3 TiO2 surface reactions…………………………………….………… 19 • 2.1.4 Role of OH radicals……….………………….……….……………… 21 2.1.5 Kinetics of TiO2 photocatalysis………….………….…………………22 2.2 Particle dispersion of TiO2……………………………………………… 24 2.2.1 Heterogeneous photocatalysis………………………….………… … 24 2.2.2 Particle aggregation……………………….………………….…….… 26 2.2.3 Methods for avoiding/minimizing particle aggregation … 28 2.3 Roles of support …………………….……………………………… ….…31 2.3.1 TiO2 supported on porous materials……………………………… .32 2.3.2 TiO2 supported on non-porous materials…….………….…….… …41 ii Table of Contents 2.3.3 Adsorbents used as a TiO2 support………………………………… 47 2.3.3.1 β-zeolite… 47 2.3.3.2 Al-pillared Montmorillonite……………….………………… 48 2.3.3.3 MCM-41 … 49 2.3.3.4 SBA-15……………………………………………….………….50 2.4 pH effect on photoreaction……………………………………………….….51 2.5 Enhancement of photocatalytic reaction rate… ………….….……………54 2.5.1 Hydrogen peroxide…………………………….………………………55 2.5.2 Ozone………………………………………………………………….60 2.5.3 Noble metal doping……………………………………………………62 2.6 Catalyst reuse………………………………………………….…………….66 2.6.1 Sedimentation separation……………………….…………………… 67 2.6.2 Magnetic separation……………………………………….………… 69 CHAPTER EXPERIMENTAL SECTION………………………………72 3.1 Reagents and apparatus……………………………………….………… 72 3.2 Synthesis of supported TiO2 photocatalysts……………… …….…….…74 3.2.1 Synthesis of MCM-41……………………………………….…… …74 3.2.2 Synthesis of supported TiO2 photocatalyst by sol-gel method… .…75 3.2.3 Synthesis of Ti-SBA-15 by co-precipitation method 75 3.2.4 Synthesis of Ti-SBA-15 by impregnation method……………….……76 3.2.5 Synthesis of silica microspheres………………….……………………76 3.2.6 Synthesis of SiO2/TiO2 core/shell photocatalysts…………………… 77 3.2.7 Synthesis of SiO2/TiO2-Pt photocatalysts…………………… ………78 3.2.8 Synthesis of TiO2 fiber……………………………………….……… 78 3.3 Characterization ……………………………………………….………… 79 iii Table of Contents 3.3.1 Scanning electron microscopy (SEM) ………………………………79 3.3.2 Energy dispersive X-ray spectrometry (EDX) .79 3.3.3 Diffusive reflectance UV-Vis spectrophotometer (DR-UV)…….….…80 3.3.4 N2 adsorption/desorption……………………………….….……… …80 3.3.5 Magic-angle spinning-nuclear magnetic resonance (MAS-NMR) spectroscopy………………………………………………………………….81 3.3.6 X-ray diffraction (XRD)…………………………….…………………81 3.3.7 X-ray photoelectron spectroscopy (XPS)…………….……………… 82 3.3.8 Zeta potential……………………………………….………………….82 3.3.9 Transmission electron microscopy (TEM)……………….……………83 3.4 Evaluation of photocatalytic activity………………….……………….… 83 CHAPTER REDISPERSION OF TiO2 NANOPARTICLES IN AQUEOUS PHASE BY VARYING SOLUTION pH AND SURFACE MODIFICATION WITH POLYELECTROLYTE………………….… 86 4.1 Introduction………………………………….………….……….……………86 4.2 Results and discussion……………………….…….………………… ……88 4.2.1 Effect of catalyst dosage on its photoactivity………………… ……88 4.2.2 Redispersion of TiO2 nanoparticles in aqueous phase by varying solution pH…………………………………………………………………….92 4.2.3 Redispersion of TiO2 nanoparticles in aqueous phase by surface modification with polyelectrolyte…………….………….… ……………… 98 4.3 Summary…………………………….…………………… ………… ……103 iv Table of Contents CHAPTER ADVANCED OXIDATION OF ORANGE II USING TiO2 SUPPORTED ON POROUS ADSORBENTS: THE ROLE OF pH, H2O2 AND O3………………………………………………….… .104 5.1 Introduction…………………………… ………………………….…….….104 5.2 Results and discussion………………………………………….….…… 105 5.2.1 Characterization of the catalysts …………………….……… …….105 5.2.2 Dark adsorption of orange II ………………………………… … 109 5.2.3 Photocatalytic degradation of orange II…….………………… ….112 5.2.4 Total organic carbon (TOC) degradation ……………………… .114 5.3 Summary… 120 CHAPTER CHARACTERIZATION AND PHOTOCATALYTIC PROPERTIES OF TITANIUM-CONTAINING MESOPOROUS SBA-15……………………………………………….….………………………….121 6.1 Introduction………………………………………….……………… …121 6.2 Results and discussion………………………………………………… 124 6.2.1 Characterization of photocatalysts ……………………………….…124 6.2.2 Photocatalytic properties of titanium-containing SBA-15.………… 137 6.3 Summary…………………………………………………….…………… 142 CHAPTER PREPARATION AND CHARACTERIZATION OF SiO2/TiO2-Pt CORE/SHELL NANOSTRUCTURES AND EVALUATION OF THEIR PHOTOCATALYTIC ACTIVITY… 143 7.1 Introduction…………………………….………………………….……… 143 7.2 Results and discussion……………………….…………………………… 145 7.2.1 Characterization of the SiO2/TiO2 core/shell photocatalysts …… 145 v Table of Contents 7.2.2 Photocatalytic activity of the SiO2/TiO2 core/shell photocatalysts… 152 7.2.3 Reuse of the SiO2/TiO2 core/shell photocatalysts….……….……… 153 7.2.4 Characterization of the SiO2/TiO2-Pt photocatalysts…….… ……….156 7.2.5 Photocatalytic activity of SiO2/TiO2-Pt photocatalysts……….…… 163 7.3 Summary………………………………………………………………… 169 CHAPTER CONCLUSIONS AND RECOMMENDATIONS… .170 8.1 Conclusions……………………………………………………… ……… 170 8.2 Recommendations……………………….…………….…………………….172 REFERENCES……………………………………………………………… … 175 APPENDIX…………………………………………………….…….………… 194 vi Summary Summary Due to the rapid urban and industrial development worldwide, large amounts of chemicals are being used and subsequently released into the natural environment Many control technologies, such as physical adsorption, chemical decomposition and bio-degradation, are available to remove these contaminants Among various treatment technologies, considerable attention has been given to photocatalytic degradation of contaminants by semiconductor photocatalysts due to several advantages, such as complete mineralization of organic compounds, minimization of waste disposal problems and cost reduction TiO2 has been proven to be the most suitable photocatalyst for widespread environmental applications due to many merits TiO2 photocatalysis is a well established advanced oxidation process for the purification of contaminated air and wastewater streams and such applications have been well documented over the last two decades However, some disadvantages of bare TiO2 nanoparticles impede its application as a photocatalyst in wastewater treatment process First, due to the aggregation of TiO2 nanoparticles in aqueous phase, the effective surface area and photocatalytic activity decay rapidly Second, the non-porous nature of TiO2 nanoparticles leads to low specific surface area and adsorption capacity for organic contaminants, thus a low photocatalytic activity In addition, the issues of catalyst recovery and possible reuse have largely hindered the commercialization of TiO2 photocatalyst Extensive research has been carried out to enhance the surface area and improve the photocatalytic property of TiO2, whereas many issues still need to be addressed for maximum utilization of the supported catalysts For example, the effect of the support vii Summary morphology on photocatalytic activity of synthesized catalyst and the separation and reuse of TiO2 photocatalysts are rarely investigated In this thesis work, the dispersion of TiO2 nanoparticles in aqueous phase was studied The spontaneous particle aggregation was confirmed and it could result in low photocatalytic reaction rate due to less effective surface area Two strategies, namely varying solution pH and surface modification by polyelectrolyte, were applied to prevent particle agglomeration In addition, four porous materials, zeolite, Al-pillared Montmorillonite clay, mesoporous MCM-41 and SBA-15 silicates were used to synthesize supported TiO2 catalysts in order to obtain large surface area and improved photocatalytic activity The results showed that the moderate adsorption was desirable for photocatalytic reaction and external surface of support was more important for supported photocatalyst due to less mass transfer resistance and easy light accessibility The non-porous silica microsphere was also used to prepare photocatalyst with core/shell structure Furthermore, the Pt nanoparticles were evenly dispersed on TiO2 shell by a self assembly method to enhance the photocatalytic activity of SiO2/TiO2 core/shell photocatalyst In addition to the photocatalytic activity, separation of photocatalyst from reaction media by sedimentation was investigated and reuse of supported TiO2 catalysts was studied as well The prepared core/shell photocatalyst showed good photocatalytic activity and excellent separation ability viii Reference Heijman, S.G.J., H.N Stein Electrostatic and Sterical Stabilization of TiO2 Dispersions Langmuir, 11, pp.422-427 1995 Herrmann, J.M Heterogeneous Photocatalysis: Fundamentals and Applications to the Removal of Various Types of Aqueous Pollutants Catal Today, 53, pp.115-129 1999 Hislop, K.A., J.R Bolton The Photochemical Generation of Hydroxyl Radicals in the UV-Vis/Ferrioxalate/H2O2 System Environ Sci Technol., 33, pp.3119-3126 1999 Hoffmann, M.R., S.T Martin, W Choi, D.W Bahnemann Environmental Applications of Semiconductor Photocatalysis Chem Rev., 95, pp.69-96 1995 Hoogeveen, N.G., M.A.C Stuart, G.J Fleer Polyelectrolyte Adsorption on Oxides J Colloid Interface Sci., 182, pp.133-145 1996 Houas, A., H Lachheb, M Ksibi, E Elaloui, C Guillard, L.M Herrmann Photocatalytic Degradation Pathway of Methylene Blue in Water Appl Catal B: Environ., 31, pp.145-157 2001 Hsiao, C.Y., C.L Lee, D.F Ollis Heterogeneous Photocatalysis: Degradation of Dilute Solutions of Dichloromethane (CH2Cl2), Chloroform (CHCl3), and Carbon Tetrachloride (CCl4) with Illuminated TiO2 Photocatalyst J Catal., 82, pp.418-423 1983 Hu, H.Q Sonochemical Degradation of Organic Compounds in Water M Eng thesis, National University of Singapore (2005) Hustert, K., R.G Zepp Photocatalytic Degradation of Selected Azo dye Chemosphere, 24, pp.335-342 1992 Hwang, S., M.C Lee, W Choi Highly Enhanced Photocatalytic Oxidation of CO on Titania Deposited with Pt Nanoparticles: Kinetics and Mechanism Appl Catal B: Environ., 46, pp.49-63 2003 Inel, Y., A.N Ӧkte Photocatalytic Degradation of Malonic Acid in Aqueous Suspensions of Titanium Dioxide: An Initial Kinetic Investigation of CO2 Photogeneration J Photochem Photobiol A: Chem., 96, pp.175-180 1996 Ishibai, Y., J Sato, T Nishikawa S Miyagishi, Synthesis of Visible-Light Active TiO2 Photocatalyst with Pt-Modification: Role of TiO2 Substrate for High Photocatalytic Activity Appl Catal B: Environ., In press 2007 Izumi, Y., K Urabe, M Onaka Clay as Potential Catalyst Material In Zeolite, Clay, and Heteropoly Acid in Organic Reactions, pp.49-94 VCH 1992 Janus, M., B Tryba, M Inagaki, A.W Morawski New Preparation of a Carbon-TiO2 Photocatalyst by Carbonization of n-Hexane Deposited on TiO2 Appl Catal B: Environ., 52, pp.61-67 2004 180 Reference Janus, M., M Inagaki, B Tryba, M Toyoda, A.W Morawski Carbon-Modified TiO2 Photocatalyst by Ethanol Carbonization Appl Catal B: Environ., 63, pp.272-276 2006 Ji, D., R Zhao, G.M Lv, G Qian, L Yan, J.S Suo Direct Synthesis, Characterization and Catalytic Performance of Novel Ti-SBA-1 Cubic Mesoporous Molecular Sieves Appl Catal A: Gen., 281, pp.39-45 2005 Jing, L.Q., X.J Sun, W.M Cai, Z.L Xu, Y.G Du, H.G Fu The Preparation and Characterization of Nanoparticle TiO2/Ti Films and their Photocatalytic Activity J Phys Chem Solids, 64, pp.615-623 2003 Jung, S.C., B.H Kim, S.J Kim, N Imaishi, Y.I Cho Characterization of a TiO2 Photocatalyst Film Deposited by CVD and Its Photocatalytic Activity Chem Vapor Depos., 11, pp.137-141 2005 Kang, M., W.J Hong, M.S Park Synthesis of High Concentration TitaniumIncorporated Nanoporous Silicates (Ti-NPS) and Their Photocatalytic Performance for Toluene Oxidation Appl Catal B: Environ., 53, pp.195-205 2004 Kawi, S., S.C Shen, P.L Chew Generation of BrØnsted Acid Sites in Si-MCM-41 by Grafting of Phosphorus Species J Mater Chem., 12, pp.1582-1586 2002 Keller, V., P Bernhardt, F Garin Photocatalytic Oxidation of Butyl Acetate in Vapor Phase on TiO2, Pt/TiO2 and WO3/TiO2 Catalysts J Catal., 215, pp.129-138 2003 Khalil, L.B.; W.E Mourad, M.W Rophael Photocatalytic Reduction of Environmental Pollutant Cr (VI) over Some Semiconductors under UV/Visible Light Illumination Appl Catal B: Environ., 17, pp.267-273 1998 Kim, S., W Choi Dual Photocatalytic Pathways of Trichloroacetate Degradation on TiO2: Effect of Nanosized Platinum Deposits on Kinetics and Mechanism J Phys Chem B, 106, pp.13311-13317 2002 Kim, Y., M Yoon TiO2/Y-Zeolie Encapsulating Intramolecular Charge Transfer Molecules: A New Photocatalyst for Photoreduction of Methyl Orange in Aqueous Medium J Mol Catal A: Chem., 168, pp.257-263 2001 Klare, M., J Scheen, K Vogelsang, H Jacobs, J.A.C Broekaert Degradation of Short-Chain Alkyl- and Alkanolamindes by TiO2- and Pt/TiO2-Assisted Photocatalysis Chemosphere, 41, pp.353-362 2000 Kong, Y., X.F, Guo, F.M Zhang, S.Y Jiang, J Wang, Y.N Lu, Q.J Yan Synthesis of Ti-containing MCM41 using Ti(SO4)2 as Ti source Mater Lett., 59, pp.3099-3101 2005 Konstantinou, I.K., T.A Albanis TiO2-Assisted Photocatalytic Degradation of Azo Dyes in Aqueous Solution: Kinetic and Mechanistic Investigations A review Appl Catal B: Environ., 49, pp.1-14 2004 181 Reference Kopf, P., E Gilbert, S.H Eberle TiO2 Photocatalytic Oxidation of Monochloroacetic Acid and Pyridine: Influence of Ozone J Photochem Photobiol A: Chem., 136, pp.163-168 2000 Koumoto, K., S Seo, T Sugiyama, W.S Seo, W.J Dressick Micropatterning of Titanium Dioxide on Self-Assembled Monolayers Using a Liquid-Phase Deposition Process Chem Mater., 11, pp.2305-2309 1999 Krapfenbauer, K., N Getoff Comparative Studies of Photo- and Radiation-Induced Degradation of Aqueous EDTA Synergistic Effects of Oxygen, Ozone and TiO2 Radiat Phys Chem., 55, pp.385-393 1999 Kresge, C.T., M.E Leonowicz, W.J Roth, J.C Vartuli, J.S Beck Ordered Mesoporous Molecular Sieves Synthesized by a Liquid-Crystal Template Mechanism Nature, 359, pp.710-712 1992 Kumar, A., A.K Jain Photophysics and Photocatalytic properties of Ag+-Activated Sandwich Q-CdS-TiO2 J Photochem Photobiol A: Chem., 156, pp.207-218 2003 Kuo, D.H., C.N Shueh Growth and Properties of TiCl4-Derived CVD Titanium Oxide Films at Various CO2/H2 Inputs Chem Vapor Depos., 9, pp.265-271 2003 Kuo, T.J., C.N Lin, C.L Kuo, M.H Huang Growth of Ultralong ZnO Nanowires on Silicon Substrates by Vapor Transport and Their Use as Recyclable Photocatalysts Chem Mater 19, pp.5143-5147 2007 Kurinobu, S., K Tsurusaki, Y Natui, M Kimata, M Hasegawa Decomposition of Pollutants in Wastewater Using Magnetic Photocatalyst Particles J Magn Magn Mater., 310, pp.e1025-e1027 2007 • Lawless, D., N Serpone, D Meisel Role of OH Radicals and Trapped Holes in Photocatalysis A Pulse Radiolysis Study, J Phys Chem., 95, pp.5166-5170 1991 Lea, J., A.A Adesina Oxidative Degradation of 4-Nitrophenol in UV-Illuminated Titania Suspension J Chem Technol Biotechnol., 76, pp.803-810 2001 Lebrette, S., C Pagnoux, P Abélard Stability of Aqeuous TiO2 Suspensions: Influence of Ethanol J Colloid Interface Sci., 280, pp.400-408 2004 Lee, J., W Choi Photocatalytic Reactivity of Surface Platinized TiO2: Substrate Specificity and the Effect of Pt Oxidation State J Phys Chem B, 109, pp.7399-7406 2005 Lee, J.M., M.S Kim, B.W Kim Photodegradation of Bisphenol-A with TiO2 Immobilized on the Glass Tubes Including the UV Light Lamps Water Res., 38, pp.3605-3613 2004 Lee, S.W., J Drwiega, C.Y Wu, D Mazyck, W.M Sigmund Anatase TiO2 Nanoparticle Coating on Barium Ferrite Using Titanium Bis-Ammonium Lactato 182 Reference Dihydroxide and Its Use as a Magnetic Photocatalyst Chem Mater., 16, pp.11601164 2004 Legrini, O., E Oliveros, A.M Braun Photochemical Processes for Water Treatment Chem Rev., 93, pp.671-698 1993 Lepore, G.P., L Persaud, C.H Langford Supporting Titanium Dioxide Photocatalysts on Silica Gel and Hydrophobically Modified Silica Gel J Photochem Photobiol A: Chem., 98, pp.103-111 1996 Lewis, N.S., M.L Rosenbluth Theory of Semiconductor Materials In Photocatalysis: Fundamentals and Applications, ed by N Serpone and E Pelizzetti, pp.46-95 Wiley 1989 Li, G., X.S Zhao, M.B Ray Advanced Oxidation of Orange II Using TiO2 Supported on Porous Adsorbents: The Role of pH, H2O2 and O3 Sep Purif Technol., 55, pp.9197 2007 Li, H.X., Z.F Bian, J Zhu, D.Q Zhang, G.S Li, Y.N Huo, H Li, Y.F Lu Mesoporous Titania Spheres with Tunable Chamber Structure and Enhanced Photocatalytic Activity J Am Chem Soc., 129, pp.8406-8407 2007 Li, H.Y., C.P Tripp Interaction of Sodium Polyacrylate Adsorbed on TiO2 with Cationic and Anionic Surfactants Langmuir, 20, pp.10526-10533 2004 Li, J., H.C Zeng Preparation of Monodisperse Au/TiO2 Nanocatalysts via SelfAssembly Chem Mater., 18, pp.4270-4277 2006 Li, L.S., W.P Zhu, P.Y Zhang, Z.Y Chen, W.Y Han Photocatalytic Oxidation and Ozonation of Catechol over Carbon-Black-Modified Nano-TiO2 Thin Films Supported on Al Sheet Water Res., 37, pp.3646-3651 2003 Linsebigler, A.L., G.Q Lu, J.T Yates, Jr Photocatalysis on TiO2 Surface: Principles, Mechanisms, and Selected results Chem Rev., 95, pp.735-758 1995 Linsebigler, A., C Rusu, J.T Yates, Jr Absence of Platinum Enhancement of a Photoreaction on TiO2-CO Photooxidation on Pt/TiO2 (110) J Am Chem Soc., 118, pp.5284-5289 1996 Litter, M.I Heterogeneous Photocatalysis: Transitiion Metal Ions in Photocatalytic Systems Appl Catal B: Environ., 23, pp.89-114 1999 Liu, Z.Y., D.D Sun, P Guo, J.O Leckie An Efficient Bicomponent TiO2/SnO2 Nanofiber Photocatalyst Fabricated by Electrospinning with a Side-by-Side Dual Spinneret Method Nano Lett., 7, pp.1081-1085 2007 Low, G.K.C., S.R McEvoy, R.W Matthews Formation of Nitrate and Ammonium Ions in Titanium Dioxide Mediated Photocatalytic Degradation of Organic Compounds Containing Nitrogen atoms Environ Sci Technol., 25, pp.460-467 1991 183 Reference Luan, Z.H., L Kevan Electron Spin Resonance and Diffuse Reflectance UltravioletVisible Spectroscopies of Vanadium Immobilized at Surface Titanium Centers of Titanosilicate Mesoporous TiMCM-41 Molecular Sieves J Phys Chem B, 101, pp.2020-2027 1997 Luan, Z.H., E.M Maes, P.A van der Heide, D.Y Zhao, R.S Czernuszewicz, L Kevan Incorporation of Titanium into Mesoporous Silica Molecular Sieve SBA-15 Chem Mater., 11, pp.3680-3686 1999 Luan, Z.H., L Kevan Characterization of Titanium-Containing Mesoporous Silica Molecular Sieve SBA-15 and Generation of Paramagnetic Hole and Electron Centers Micropor Mesopor Mater., 44-45, pp.337-344 2001 Machado, A.E.H., J.A de Miranda, R.F de Freitas, E.T.F.M Duarte, L.F Ferreira, Y.D.T Albuquerque, R Ruggiero, C Sattler, L de Oliveira Destruction of the Organic Matter Present in Effluent from a Cellulsoe and Paper Industry Using Photocatalysis J Photochem Photobiol A: Chem., 155, pp.231-241 2003 Malato, S., J Blanco, C Richter, B Braun, M.I Maldonado Enhancement of the Rate of Solar Photocatalytic Mineralization of Organic Pollutants by Inorganic Oxidizing Species Appl Catal B: Environ., 17, pp.347-356 1998 Mandzy, N., E Grulke, T Druffel Breakage of TiO2 Agglomerates in Electrostatically Stabilized Aqueous Dispersions Powder Technol., 160, pp.121-126 2005 Mange, F., P Couchot, A Foissy, A Pierre Effects of Sodium and Calcium Ions on the Aggregation of Titanium Dioxide, at High pH, in Aqueous Dispersions J Colloid Interface Sci.,159, pp.58-67 1993 Marchese, L., T Maschmeyer, E Gianotti, S Coluccia, J.M Thomas Probing the Titanium Sites in Ti-MCM41 by Diffuse Reflectance and Photoluminescence UV-Vis Spectroscopies J Phys Chem B., 101, pp.8836-8838 1997 Martyanov, I.N., E.N Savinov, K.J Klabunde Influence of Solution Composition and Ultrasonic Treatment on Optical Spectra of TiO2 Aqueous Suspensions J Colloid Interface Sci., 267, pp.111-116 2003 Massam, J., D.R Brown Acid-Treated Montmorillonite Supports for Copper (II) Nitrate Oxidation Reagents Appl Catal A: Gen., 172, pp.259-264 1998 Matthews, R.W Hydroxylation Reactions Induced by Near-Ultraviolet Photocatalysis of Aqueous Titanium Dioxide Suspensions J Chem Soc., Faraday Trans., 80, pp.457471 1984 Matthews, R.W Purification of Water with Near-UV Illuminated Suspensions of Titanium Dioxide, Water Res., 24, pp.653-660 1990 Melero, J.A., J.M Arsuaga, P de Frutos, J Iglesias, J Sainz, S Blázquez Direct Synthesis of Titanium-Substituted Mesostructured Materials Using Non-Ionic 184 Reference Surfactants and Titanocene Dichloride Micropor Mesopor Mater., 86, pp.364-373 2005 Miller, R., R Fox Treatments of Organic Contaminants in Air by Photocatalytic Oxidation: A Commercialization Perspective In Photocatalytic Purification and Treatment of Water and Air, ed by D.F Ollis and H Al-Ekabi, pp.573-578 Elsevier 1993 Mills, A., S Morris, R Davies Photomineralizaiton of 4-Chlorophenol Sensitized by Titanium Dioxide: A Study of the Intermediates J Photochem Photobiol A: Chem., 70, pp.183-191 1993 Mills, A., S Morris Photomineralization of 4-Chlorophenol Sensitized by Titanium Dioxide: A Study of the Initial Kinetics of Carbon Dioxide Photogeneration J Photochem Photobiol A: Chem., 71, pp.75-83 1993 Mills, A., X Domènech Photoassisted Oxidation of Nitrite to Nitrate over Different Semiconducting Oxides J Photochem Photobiol A: Chem., 72, pp.55-59 1993 Mills, A., R.H Davies, D Worsley Water Purification by Semiconductor Photocatalysis Chem Soc Rev., 22, pp.417-425 1993 Mills, A., S.L Hunte An Overview of Semiconductor Photocatalysis J Photochem Photobiol A: Chem., 108, pp.1-35 1997 Minero, C., C Aliberti, E Pelizzetti, R Terzian, N Serpone Kinetic Studies in Heterogeneous Photocatalysis AM1 Simulated Sunlight Photodegradation over Titania in Aqueous Media: A First Case of Fluorinated Aromatics and Identification of Intermediates Langmuir, 7, pp.928-936, 1991 Minero, C., F Catozzo, E Pelizzetti Role of Adsorption in Photocatalyzed Reactions of Organci Molecules in Aqeuous TiO2 Suspensions Langmuir, 8, pp.481-486 1992 Mohai, M., I Bertóti, M Révész XPS Study of the State of Oxygen on a Chemically Treated Glass Surface Surf Interface Anal., 15, pp.364-368 1990 Morey, M., A Davidson, G Stucky A New Step toward Transition Metal Incorporation in Cubic Mesoporous Materials: Preparation and Characterization of TiMCM-48 Microporo Mater., 6, pp 99-104 1996 Morishige, K., F Kanno, S Ogawara, S Sasaki Hydrated Surface of Particulate Titanium Dioxide Prepares by Pyrolysis of Alkoxide, J Phys Chem., 89, pp.44044408 1985 Mukhopadhyay, S.M., S.H Garofalini Surface Studies of TiO2-SiO2 Glasses by XRay Photoelectron Spectroscopy J Non-Cryst Solids, 126, pp.202-208 1990 185 Reference Muradov, N.Z Solar Detoxification of Nitroglycerine-Contaminated Water Using Immobilized Titania Sol Energy, 52, pp.283-288 1994 Nagaoka, S., Y Hamasaki, S.I Ishihara, M Nagata, K Iio, C Nagasawa, H Ihara Preparation of Carbon/TiO2 Microsphere Composites from Cellulose/TiO2 Microsphere Composites and Their Evaluation J Mol Catal A: Chem., 177, pp.255263 2002 Nakamura, H., M Ishii, A Tsukigase, M Harada, H Nakano Close-Packed Colloidal Crystalline Arrays Composted of Polystyrene Latex Coated with Titania Nanosheets Langmuir, 21, pp.8918-8922 2005 Newalkar, B.L., J Olanrewaju, S Komarneni Direct Synthesis of TitaniumSubstituted Mesoporous SBA-15 Molecular Sieve under Microwave-Hydrothermal Conditions Chem Mater., 13, pp.552-557 2001 Ninness, B.J., D.W Bousfield, C.P Tripp The Importance of Adsorbed Cationic Surfactant Structure in Dictating the Subsequent Interaction of Anionic Surfactants and Polyelectrolytes with Pigment Surfaces Colloid Surface A., 203, pp.21-36 2002 Nozawa, K., H Gailhanou, L Raison, P Panizza, H Ushiki, E Sellier, J.P Delville, M.H Delville Smart Sontrol of Monodisperse Stӧber Silica Particles: Effect of Reactant Addition Rate on Growth Process Langmuir, 21, pp.1516-1523 2005 Occelli, M.L., S Biz, A Auroux Effects of Isomorphous Substitution of Si with Ti and Zr in Mesoporous Silicates with the MCM-41 structure Appl Catal A: Gen., 183, pp.231-239 1999 Ohno, T., F Tanigawa, K Fujihara, S Izumi, M Matsumura Photocatalytic Oxidation of Water on TiO2-Coated WO3 Particles by Visible Light Using Iron (III) Ions as Electron Acceptor J Photochem Photobiol A: Chem., 118, pp.41-44 1998 Ohno, T., Y Masaki, S Hirayama, M Matsumura TiO2-Photocatalyzed Epoxidation of 1-Decene by H2O2 under Visible Light J Catal., 204, pp.163-168 2001 Ollis, D.F., E Pelizzetti, N Serpone Heterogeneous Photocatalysis in the Environment: Application to Water Purification In Photocatalysis: Fundamentals and Applications, ed by N Serpone and E Pelizzetti, pp.603-637 Wiley 1989 Ollis, D.F., E Pelizzetti, N Serpone Destruction of Water Contaminants Environ Sci Technol., 25, pp.1522-1529 1991 Ooka, C., S Akita, Y Ohashi, T Horiuchi, K Suzuki, S.I Komai, H Yoshida, T Hattori Crystallization of Hydrothermally Treated TiO2 Pillars in Pillared Montmorillonite for Improvement of Photocatalytic Activity J Mater Chem., 9, pp.2943-2952 1999 Ooka, C., H Yoshida, M Horio, K Suzuki, T Hattori Adsorptive and Photocatalytic Performance of TiO2 Pillared Montmorillonite in Degradation of Endocrine Disruptors Having Different Hydrophobicity Appl Catal B: Environ., 41, pp.313-321 2003 186 Reference Palmisano, L., V Augugliaro, M Schiavello, A Sclafani Influence of Acid-Base Properties on Photocatalytic and Photochemical Processes J Mol Catal A: Chem., 56, 284-295 1989 Palmisano, L., A Sclafani Thermodynamics and Kinetics for Heterogeneous Photocatalytic Processes In Heterogeneous Photocatalysis, ed by M Schiavello, pp.109-132 New York: Wiley, 1997 Pareek, V.K, A.A Adesina Analysis of Photocatalytically Reaction Systems: Kinetics Modeling and Reactor Design via Computational Fluid Dynamics In Handbook of Photochemistry and Photobiology, ed by H.S Nalwa, pp.346-367 American Scientific Publishers, 2003 Park, H., W Choi Visible Light and Fe(III)-Mediated Degradation of Acid Orange in the Absence of H2O2 J Photochem Photobiol A: Chem., 159, pp.241-247 2003 Pawelec, B., R Mariscal, J.L.G Fierro, A Greenwood, P.T Vasudevan CarbonSupported Tungsten and Nickel Catalysts for Hydrodesulfurization and Hydrogenation Reactions Appl Catal A: Gen., 206, pp.295-307 2001 Peng, T.Y., D Zhao, K Dai, W Shi, K Hirao Synthesis of Titanium Dioxide Nanoparticles with Mesoporous Anatase Wall and High Photocatalytic Activity J Phys Chem B, 109, pp.4947-4952 2005 Peterson, M.W., J.A Turner, A.J Nozik Mechanistic Studies of the Photocatalytic Behavior of TiO2 Particles in a Photoelectrochemical Slurry Cell and the Relevance to Photodetoxification Reactions J Phys Chem., 95, pp.221-225 1991 Piscopo, A., D Robert, J.V Weber Influence of pH and Chloride Anion on the Photocatalytic Degradation of Organic Compounds Part I Effect on the Benzamide and para-Hydroxybenzoic Acid in TiO2 Aqueous Solution Appl Catal B: Environ., 35, pp.117-124 2001 Pizem, H., C.N Sukenik, U Sampathkumaran, A.K McIlwain, M.R De Guire Effect of Substrate Surface Functionality on Solution-Deposited Titanium Films Chem Mater., 14, pp.2476-2485 2002 Poulios, I., E Micropoulou, R Panou, E Kostopoulou Photooxidation of Eosin Y in the Presence of Semiconducting Oxides Appl Catal B: Environ., 41, pp.345-355 2003 Pruden, A.L., D.F Ollis Photoassisted Heterogeneous Catalysis: The Degradation of Trichloroethylene in Water J Catal., 82, pp.404-417 1983 Puttamraju, P.K Performance Improvement of TiO2 Supported on Adsorbents for Photocatalytic Degradation of Volatile Organics M Eng thesis, National University of Singapore (2004) 187 Reference Qiu, W., Y Zheng, K.A Haralampides Study on a Novel POM-Based Magnetic Photocatalyst: Photocatalytic Degradation and Magnetic Separation Chem Eng J., 125, pp.165-176 2007 Raimondi, M.E., L Marchese, E Gianotti, T Maschmeyer, J.M Seddon, S Coluccia One-Pot Incorporation of Titanium Catalytic Sites into Mesoporous True Liquid Crystal Templated (TLCT) Silica Chem Commun., pp.87-88 1999 Rajh, T., O.G Poluektov, M.C Thurnauer Charge Separation in Titanium Oxide Nanocrystalline Semiconductors Revealed by Magnetic Resonance In Chemical Physics of Nanostructured Semiconductors, ed by A.I Kokorin and D.W Bahnemann, pp.1 – 34 Netherlans, VSP 2003 Reddy, E.P., L Davydov, P Smirniotis TiO2-Loaded Zeolites and Mesoporous Materials in the Sonophotocatalytic Decomposition of Aqueous Organic Pollutants: The Role of the Support, Appl Catal B: Environ., 42, pp.1-11 2003 Reutergardh, L.B., M Iangphasuk Photocatalytic Decolourization of Reactive Azo Dye: A Comparison between TiO2 and CdS Photocatalysis Chemosphere, 35, pp.585596 1997 Rodrigues, S., K.T Ranjit, S Uma; I.N Martyanov, K.J Klabunde Single-Step Synthesis of a Highly Active Visible-Light Photocatalyst for Oxidation of a Common Indoor Air Pollutant: Acetaldehyde Adv Mater., 17, pp.2467-2471 2005 Saquib, M., M Muneer Titanium Dioxide Mediated Photocatalyzed Degradation of a Textile Dye Derivative, Acid Orange 8, in Aqueous Suspensions Desalinaiton, 155, pp.255-263 2003 Sampath, S., H Uchida, H Yoneyama Photocatalytic Degradation of Gaseous Pyridine over Zeolite-Supported Titanium Dioxide J Catal., 149, pp.189-194 1994 Sato, T., S Kohnosu Effect of Surfactant Concentration on the Stability of Aqueous Titanium Dioxide Suspensions J Colloid Interface Sci., 143, pp.434-439 1991 Selwood, P.W Magnetochemistry, pp.306-381 New York, Interscience Publishers, 1956 Shen, Y.S., Y Ku Decomposition of Gas-Phase Trichloroethene by the UV/TiO2 Process in the Presence of Ozone Chemosphere, 46, pp.101-107 2002 Shimizu, K.I., T Kaneko, T Fujishima, T Kodama, H Yoshida, Y Kitayama Selective Oxidation of Liquid Hydrocarbons over Photoirradiated TiO2 Pillared Clays Appl Catal A: Gen., 225, pp.185-191 2002 Shyu, J.Z., K Otto Characterization of Pt/γ-Alumina Catalysts Containing Ceria J Catal., 115, pp.16-23 1989 188 Reference Sindorf, D.W., G.E Maciel Cross-Polarization/Magic-Angle-Spinning Silicon-29 Nuclear Magnetic Resonance Study of Silica Gel Using Trimethylsilane Bonding as a Probe of Surface Geometry and Reactivity J Phys Chem., 86, pp.5208-5219 1982 So, W.W., S.B Park, K.J Kim, C.H Shin, S.J Moon The Crystalline Phase Stability of Titania Particles Prepared at Room Temperature by the Sol-Gel Method J Mater Sci., 36, pp.4299-4305 2001 Strohm, H., P Löbmann Liquid-Phase Deposition of TiO2 on Polystyrene Latex Particles Functionalized by the Adsorption of Polyelectrolytes Chem Mater., 17, pp.6772-6780 2005 Subramanian, V., E wolf, P.V Kamat Semiconductor-Metal Composite Nanostructures To What Extent Do Metal Nanoparticles Improve the Photocatalytic Activity of TiO2 Films? J Phys Chem B, 105, pp.11439-11446 2001 Subramanian, V., E.E Wolf, P.V Kamat Green Emission of Probe Photoinduced Charging Events in ZnO-Au Nanoparticles Charge Distribution and Fermi-Level Equilibration J Phys Chem B, 107, pp.7479-7485 2003 Subramanian, V., E.E Wolf, P.V Kamat Catalysis with TiO2/Gold Nanocomposites Effect of Metal Particle Size on the Fermi Level Equilibration J Am Chem Soc., 126, pp.4943-4950 2004 Suda, Y., T Morimoto Molecularly Adsorbed H2O on the Bare Surface of TiO2 (Rutile) Langmuir, 3, pp.786-788 1987 Sun, L.Z., J.R Bolton Determination of Quantum Yield for the Photochemical Generation of Hydroxyl Radicals in TiO2 Suspensions J Phys Chem., 100, pp.41274134 1996 Tada, H., O Nishio, N Kubo, H Matsui, M Yoshihara, T Kawahara, H Fukui, S Ito Dispersion Stability of TiO2 Nanoparticles Covered with SiOX Monolayers in Water J Colloid Interface Sci., 306, pp.274-280 2007 Takeda, N., T Torimoto, S Sampath, S Kuwabata, H Yoneyama Effect of Inert Supports for Titanium Dioxide Loading in Enhancement of Photodecomposition Rate of Gaseous Propionaldehyde J Phys Chem., 99, pp.9986-9991 1995 Tanev, P.T., M Chibwe, T.J Pinnavaia Titanium-Containing Mesoporous Molecular Sieves for Catalytic Oxidation of Aromatic Compounds Nature, 368, pp.321-323 1994 Tang, W.Z., C.P Huang Photocatalyzed Oxidation Pathways of 2,4-Dichlorophenol by CdS in Basic and Acidic Aqueous Solutions Water Res., 29, pp.745-756 1995 Taramasso, M., G Perego, B Notari, S.P.A Snamprogetti Preparation of Porous Crystalline Synthetic Material Comprised of Silicon and Titanium Oxides U.S Patent 4,410,501, 1982 189 Reference Terzian, R., N Serpone, C Minero, E Pelizzetti Photocatalyzed Mineralization of Cresols in Aqueous Media with Irradiation Titania J Catal., 128, pp.352-365 1991 Thompson, T.L., J.T Yates Jr Surface Science Studies of the Photoactivation of TiO2New Photochemical Processes Chem Rev., 106, pp.4428-5543 2006 Torimoto, T., Y Okawa, N Takeda, H Yoneyama Effect of Activated Carbon Content in TiO2-Loaded Activated Carbon on Photodegradation Behaviors of Dichloromethane J Photochem Photobiol A: Chem., 103, pp.153-157 1997 Toyoda, M., Y Nanbu, T Kito, M Hirano, M Inagaki Preparation and Performance of Anatase-Loaded Porous Carbons for Water Purification Desalination, 159, pp.273282 2003 Tunesi, S., M Anderson Influence of Chemisorption on the Photodecomposition of Salicylic Acid and Related Compounds Using Suspended TiO2 Ceramic Membranes J Phys Chem., 95, pp.3399-3405 1991 Turchi, C.S., D.F Ollis Photocatalytic Degradation of Organic Water Contaminants: Mechanisms Involving Hydroxyl Radical Attack J Catal., 122, pp.178-192 1990 Uchida, H., S Itoh, H Yoneyama Photocatalytic Decomposition of Propyzamide Using TiO2 Supported on Activated Carbon Chem Lett., 12, pp.1995-1998 1993 Uetsuka, H., C Pang, A Sasahara, H Onishi Photochemical Reaction of Trimethyl Acetate on Pt/TiO2 (110) Langmuir, 21, pp.11802-11805 2005 Vinu, A., B.M Devassy, S.B Halligudi, W Böhlmann, M Hartmann Highly Active and Selective AlSBA-15 Catalysts for the Vapor Phase tert-Butylation of Phenol Appl Catal A: Gen., 281, pp.207-213 2005 Wang, X.J., D.D Hu, J.X Yang Synthesis of PAM/TiO2 Composite Microspheres with Hierarchical Surface Morphologies Chem Mater., 19, pp.2610-2621 2007 Wei, T.Y., C.C Wan Heterogeneous Photocatalytic Oxidation of Phenol with Titanium Dioxide Powders Ind Eng Chem Res., 30, pp.1293-1300 1991 Widegren, J., L Bergström Electrostatic Stabilization of Ultrafine Titania in Ethanol J Am Chem Soc., 85, pp.523-528 2002 Wittmann, G., K Demeestere, A Dombi, J Dewulf, H.V Langenhove Preparation, Structural Characterization and Photocatalytic Activity of Mesoporous Ti-Silicates Appl Catal B: Environ., 61, pp.47-57 2005 Wong, C.C., W Chu The Hydrogen Peroxide-Assisted Photocatalytic Degradation of Alachlor in TiO2 Suspensions Environ Sci Technol., 37, pp.2310-2316 2003 Wu, J.J., C.H Tseng Photocatalytic Properties of nc-Au/ZnO Nanorod Composites Appl Catal B: Environ., 66, pp.51-57 2006 190 Reference Xu, S.H, W.F Shangguan, J Yuan, M.X Chen, J.W Shi Preparations and Photocatalytic Properties of Magnetically Separable Nitrogen-Doped TiO2 Supported on Nickel Ferrite Appl Catal B: Environ., 71, pp.177-184 2007 Xu, Y.M., C.H Langford Enhanced Photoactivity of a Titanium (IV) Oxide Supported on ZSM5 and Zeolite A at Low Coverage J Phys Chem., 99, pp.11501-11507 1995 Xu, Y.M., C.H Langford Photoactivity of Titanium Dioxide Supported on MCM-41, Zeolite X and Zeolite Y J Phys Chem B, 101, pp.3115-3121 1997 Xu, Y.M., W Zheng, W.P Liu Enhanced Photocatalytic Activity of Supported TiO2: Dispersing Effect of SiO2 J Photochem Photobiol A: Chem., 122, pp.57-60 1999 Yang, Y.Z., C.H Chang, H Idriss Photocatalytic Production of Hydrogen from Ethanol over M/TiO2 Catalysts (M = Pd, Pt or Rh) Appl Catal B: Environ., 67, pp.217-222 2006 Yang, Z.Z., Z.W Niu, Y.F Lu, Z.B Hu, C.C Han Templated Synthesis of Inorganic Hollow Spheres with A Tunable Cavity Size onto Core-Shell Gel Particles Angew Chem Int Ed., 42, pp.1943-1945 2003 Yaremko, Z.M., D.M Nikipanchuk, L.B Fedushinskaya, I.G Uspenskaya Redispersion of Highly Disperse Powder of Titanium Dioxide in Aqueous Medium Colloid J., 63, pp.253-258 2001 Yaremko, Z.M., N.H Tkachenko, C Bellmann, A Pich Redispergation of TiO2 Particles in Aqueous Solutions J Colloid Interface Sci., 296, pp.565-571 2006 Yin, H.B., Y Wada, T Kitamura, S Yanagida Photoreductive Dehalogenation of Halogenated Benzene Derivatives Using ZnS or CdS Nanocrystallites as Photocatalysts Environ Sci Technol., 35, pp.227-231 2001 Yoneyama, H., T Torimoto Titanium Dioxide/Adsorbent Hybrid Photocatalysts for Photodestruction of Organic Substances of Dilute Concentrations Catal Today, 58, pp 133-140 2000 Yu, Y.X., D.S Xu Single-Crystalline TiO2 Nanorods: Highly Active and Easily Recycled Photocatalysts Appl Catal B: Environ., 73, pp.166-171 2007 Yuan, R.S., J.T Zheng, R.B Guan, Y.C Zhao Surface Characteristics and Photocatalytic Activity of TiO2 Loaded on Activated Carbon Fibers Colloid Surface A., 254, pp.131-136 2005 Zepeda, T.A., J.L.G Fierro, B Pawelec, R Nava, T Klimova, G.A Fuentes, T Halachev Synthesis and Characterization of Ti-HMS and CoMo/Ti-HMS Oxide Materials with Varying Ti Content Chem Mater., 17, pp.4062-4073 2005 Zhang, F.L., J.C Zhao, T Shen, H Hidaka, E Pelizzetti, N Serpone TiO2-Assisted Photodegradation of Dye Pollutants II Adsorption and Degradation Kinetics of Eosin 191 Reference in TiO2 Dispersions under Visible Light Irradiation Appl Catal B: Environ., 15, pp.147-156 1998 Zhang, J.Z Interfacial Charge Carrier Dynamics of Colloidal Semiconductor Nanoparticles J Phys Chem B, 104, pp.7239-7253 2000 Zhang, P.Y, F.Y Liang, G Yu, Q Chen, W.P Zhu A Comparative Study on Decomposition of Gaseous Toluene by O3/UV, TiO2/UV and O3/TiO2/UV J Photochem Photobiol A: Chem., 156, pp.189-194 2003 Zhang, W.H., J.Q Lu, B Han, M.J Li, J.H Xiu, P.L Ying, C Li Direct Synthesis and Characterization of Titanium-Substituted Mesoporous Molecular Sieve SBA-15 Chem Mater., 14, pp.3413-3421 2002 Zhang, X.W., M.H Zhou, L.C Lei TiO2 Photocatalyst Deposition by MOCVD on Activated Carbon Carbon, 44, pp.325-333 2006 Zhang, Z.B., C.C Wang, R Zakaria, J.K Ying Role of Particle Size in Nanocrystalline TiO2-Based Photocatalysts J Phys Chem B., 102, pp.10871-10878 1998 Zhao, D.Y., J.L Feng, Q.S Huo, N Melosh, G.H Fredrickson, B.F Chmelka, G.D Stucky Triblock Copolymer Syntheses of Mesoporous Silica with Periodic 50 to 300 Angstrom Pores Science, 279, pp.548-552 1998 Zhao, M.Y., S.F Chen, Y.W Tao Photocatalytic Degradation of Organophosphorus Pesticides Using Thin Films of TiO2 J Chem Tech Biotechnol., 64, pp.339-344 1995 Zhao, W., C.C Chen, X.Z Li, J.C Zhao, H Hidaka, N Serpone Photodegradation of Sulforhodamine-B Dye in Platinized Titania Dispersions under Visible Light Irradiation: Influence of Platinum as a Functional Co-Catalyst J Phys Chem B, 106, pp.5022-5028 2002 Zhao, X.S., G.Q (Max) Lu, G.J Millar Advances in Mesoporous Molecular sieve MCM-41 Ind Eng Chem Res., 35, pp.2075-2090 1996 Zhou, J., M Chen, X.G Qiao, L.M Wu Facile Preparation Method of SiO2/PS/TiO2 Multilayer Core-Shell Hybrid Microspheres Langmuir, 22, pp.10175-10179 2006 Zhou, J.K Modified Titanium Dioxide (TiO2) Photocatalysts for the Degradation of Organic Pollutants in Wastewater Ph.D thesis, National University of Singapore (2007) Zhu, H.Y., Y Lan, X.P Gao, S.P Ringer, Z.F Zheng, D.Y Song, J.C Zhao Phase Transition between Nanostructures of Titanate and Titanium Dioxide via Simple WetChemical Reactions J Am Chem Soc., 127, pp.6730-6736 2005 192 Reference Zielińska, B., J Grzechulska, R.J Kaleńczuk, A.W Morawski The pH Influence on Photocatalytic Decomposition of Organic Dyes over A11 and P25 Titanium dioxide Appl Catal B: Environ., 45, pp.293-300 2003 193 Appendix APPENDIX List of publications coming from this thesis work Papers published (or accepted) in international referred journal (1) Li, G., Zhao, X S Characterization and photocatalytic properties of titaniumcontaining mesoporous SBA-15 Industrial & Engineering Chemistry Research, 2006, 45, 3569-3573 (2) Li, G., Zhao, X S Madhumita B Ray Advanced oxidation of orange II using TiO2 supported on porous adsorbents: The role of pH, H2O2 and O3 Separation and Purification Technology 2007, 55, 91-97 (3) Gang Li, Likui Wang, Lu Lv, and X S Zhao Preparation and characterization of SiO2/TiO2-Pt core/shell nanostructures and evaluation of their photocatalytic activity Accepted by Journal of Nanoscience and Nanotechnology, 2007 (4) Likui Wang, Linhua Xia, Gang Li, Serge Ravaine, and X S Zhao Patterning the surface of submicron spheres using 3D colloidal crystal template and fabrication of various nonspherical particles Accepted by Angewandte Chemie International, 2008 Papers submitted to international referred journal (5) Li, G., Renbi, Bai, and Zhao X S Synthesis of SiO2/TiO2 core/shell nanostructures by ultrasonic-assisted liquid phase deposition method Submitted to Industrial & Engineering Chemistry Research, 2008 (6) Gang Li, Lu Lv, X.S Zhao New insights into the critical factors influencing the photocatalytic activity of TiO2 nanoparticles Ready to submit to Journal of Colloid and Interface Science 2008 194 ... 1997) On the other hand, the concentration of the contaminants typically is at a low concentration (ppm or less), and pre-concentration of these contaminants on the TiO2 surface where photons are... supported on adsorbents, irrespective of the type of adsorbents used Since the concentration of contaminants in wastewater is quite low (usually in the order of ppm), the application of supported catalysts. .. Degradation of orange II and TOC removal as a function of illumination time over 50% TiO2- Montmorillonite Figure 5.7 TOC decay during photodegradation of orange II by TiO2Montmorillonite at different