Download or read book Photocatalytic degradation of aqueous solutions of organic compounds with natural sunlight in the presence of titanium dioxide written by Ashley L. German and published by . This book was released on 1995 with total page 54 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Heterogeneous Photocatalysis written by M. Schiavello and published by . This book was released on 1997-10-09 with total page 218 pages. Available in PDF, EPUB and Kindle. Book excerpt: Photocatalysis is a reaction which is accelerated by light while a heterogeneous reaction consists of two phases ( a solid and a liquid for example). Heterogeneous Photocatalysis is a fast developing science which to date has not been fully detailed in a monograph. This title discusses the basic principles of heterogeneous photocatalysis and describes the bulk and surface properties of semiconductors. Applications of various types of photoreactions are described and the problems related to the modeling and design of photoreactors are covered.

Download or read book Heterogeneous Photocatalytic Degradation of Organic Pollutants in Water Over Nanoscale Powdered Titanium Dioxide written by Khaled M. Mezughi and published by . This book was released on 2011 with total page 212 pages. Available in PDF, EPUB and Kindle. Book excerpt: Organic contaminants from industrial and/or domestic effluents may be harmful to humans directly or indirectly by degrading the quality of the aquatic environment. Consequently these contaminants must be reduced to levels that are not harmful to humans and the environment before disposal. Chemical, physical and biological methods exist for the removal of these pollutants from effluents. Among the available chemical methods, heterogeneous photocatalytic oxidation has been found particularly effective in removing a large number of persistent organics in water. In this study, photocatalytic degradation was explored for the removal of reactive azo-dye (textile dye), triclocarban (disinfectant), clopyralid (herbicide) and three endocrine disrupting compounds (EDCs) (estrone, 17?-estradiol and 17?-ethinylestradiol) from synthetic effluents. The major factors affecting the photocatalytic processes including the initial concentration of the target compounds, the amount of catalyst, the light intensity, the type of catalyst, the electron acceptor, the irradiation time and the pH were studied. Other oxidation techniques including (O3, H2O2, UV) were also studied. Generally UV light is used in combination with titanium dioxide, as photocatalyst, to generate photoinduced charge separation leading to the creation of electron-hole pairs. The holes act as electron acceptors hence the oxidation of organics occur at these sites. These holes can also lead to the formation of hydroxyl radicals which are also effective oxidants capable of degrading the organics. The results obtained in this study indicated that photolysis (i.e. UV only) was found to have no effect on the degradation of reactive azo-dye (RO16). However, complete photocatalytic degradation of 20 mg/L (3.24?10-2 mM) RO16 was achieved in 20 minutes in the presence of 1g/L TiO2 Degussa P25 at pH 5.5. Comparison between various types of catalysts (i.e. Degussa P25, VP Aeroperl, Hombifine N) gave varied results but Degussa P25 was the most effective photocatalyst hence it was selected for this study. For RO16 the optimum catalyst concentration was 0.5 g/L TiO2 with initial concentration of 20 mg/L RO16. It was found that the disappearance of RO16 satisfactorily followed the pseudo first-order kinetics according to Langmuir-Hinshelwood (L-H) model. The rate constant was k= 0.0928 mol/min. Photodegradation of TCC was studied in 70%v acetonitrile: 30%v water solutions. UV light degraded TCC effectively and the reaction rates increased with decreasing initial concentration of TCC. UV/TiO2 gave unsatisfactory degradation of triclocarban (TCC) since only 36% were removed in 60 minutes with initial concentration of TCC 20 mg/L. The degradation of clopyralid and the EDCs was studied using three oxidation systems UV/TiO2, UV/H2O2 and O3. Complete degradation of clopyralid (3,6-DCP) was achieved with UV/TiO2 in about 90 minutes at an optimum catalyst concentration of 1g/L. Zero-order kinetics was found to describe the first stage of the photocatalytic reaction in the concentration range 0.078-0.521 mM. At pH 5 the rate constant was 2.09?10-6? 4.32?10-7 M.s-1.Complete degradation of all the three EDCs was achieved with UV/H2O2 in 60 minutes at catalyst concentration of (2.94?10-2 M). On the other hand complete degradation of the EDCs was achieved in just 2 minutes with ozonation. For high concentration EDCs, TiO2/UV gave low efficiency of degradation as compared with ozone and H2O2/UV. First-order kinetics was found to describe the photocatalytic reaction of the EDCs.

Download or read book Photodegradation of Water Pollutants written by Martin M. Halmann and published by CRC Press. This book was released on 1995-12-05 with total page 322 pages. Available in PDF, EPUB and Kindle. Book excerpt: Photodegradation of Water Pollutants, the only complete survey available of current photocatalytic methods for treating water pollutants, covers all aspects of light-stimulated detoxification. Ideal for researchers and students, this new book explains methods for pollution treatment that have proven more effective than conventional biodegradation. Photodegradation of Water Pollutants examines advanced oxidation processes that have been successful in treating the chemical substances produced by industrial effluents and intensive agriculture. These oxidation processes include irradiation with ultraviolet or visible light, the use of homogenous sensitizers, such as dyes, and the use of heterogeneous photocatalysts, such as dispersed semiconductors. In addition, Photodegradation of Water Pollutants addresses the naturally occurring self-cleaning of some pollutants in sunlit surface waters, as well as several alternative non-photochemical approaches to water treatment. Available treatment options are discussed for the main groups of water pollutants, including toxic inorganic ions (cyanides, heavy metals), hydrocarbon derivatives (oil spills, surfactants, pulp and paper wastes), halocarbons, organo-N, organo-P, and organo-S compounds. The text also contains a unique section on the economics of advanced oxidation pollution treatments.

Download or read book Photodegradation of Water Pollutants written by Martin M. Halmann and published by CRC Press. This book was released on 2024-11-01 with total page 319 pages. Available in PDF, EPUB and Kindle. Book excerpt: Photodegradation of Water Pollutants, the only complete survey available of current photocatalytic methods for treating water pollutants, covers all aspects of light-stimulated detoxification. Ideal for researchers and students, this new book explains methods for pollution treatment that have proven more effective than conventional biodegradation. Photodegradation of Water Pollutants examines advanced oxidation processes that have been successful in treating the chemical substances produced by industrial effluents and intensive agriculture. These oxidation processes include irradiation with ultraviolet or visible light, the use of homogenous sensitizers, such as dyes, and the use of heterogeneous photocatalysts, such as dispersed semiconductors. In addition, Photodegradation of Water Pollutants addresses the naturally occurring self-cleaning of some pollutants in sunlit surface waters, as well as several alternative non-photochemical approaches to water treatment. Available treatment options are discussed for the main groups of water pollutants, including toxic inorganic ions (cyanides, heavy metals), hydrocarbon derivatives (oil spills, surfactants, pulp and paper wastes), halocarbons, organo-N, organo-P, and organo-S compounds. The text also contains a unique section on the economics of advanced oxidation pollution treatments.

Download or read book Visible Light Active Photocatalysis written by Srabanti Ghosh and published by John Wiley & Sons. This book was released on 2018-03-23 with total page 626 pages. Available in PDF, EPUB and Kindle. Book excerpt: A comprehensive and timely overview of this important and hot topic, with special emphasis placed on environmental applications and the potential for solar light harvesting. Following introductory chapters on environmental photocatalysis, water splitting, and applications in synthetic chemistry, further chapters focus on the synthesis and design of photocatalysts, solar energy conversion, and such environmental aspects as the removal of water pollutants, photocatalytic conversion of CO2. Besides metal oxide-based photocatalysts, the authors cover other relevant material classes including carbon-based nanomaterials and novel hybrid materials. Chapters on mechanistic aspects, computational modeling of photocatalysis and Challenges and perspectives of solar reactor design for industrial applications complete this unique survey of the subject. With its in-depth discussions ranging from a comprehensive understanding to the engineering of materials and applied devices, this is an invaluable resource for a range of disciplines.

Download or read book Photocatalytic Degradation of Dyes written by Sushma Dave and published by Elsevier. This book was released on 2021-08-09 with total page 796 pages. Available in PDF, EPUB and Kindle. Book excerpt: Photocatalytic Degradation of Dyes: Current Trends and Future Perspectives covers in detail current trends and future aspects on photocatalytic degradation of organic dyes using novel photocatalytic techniques such as metallic nanoparticles, heterogeneous and hybrid systems using visible light irradiation. It highlights the most recent scientific and technological achievements and importance of degradation of dyes in the textile effluent by simple environmental friendly approaches using eco-friendly catalysts. It is of assistance to everyone interested in bioremediation of effluents: professionals, consulting engineers, academicians, and research scholars as well. - Describes the basic photocatalytic techniques and their application in wastewater treatment - Covers the key reactive species accounting for the photodegradation of different dyes, providing helpful guidelines that could be applied to foster the development of efficient photodegradation systems - Includes Description of a wide variety of catalysts and their application in degradation of dyes in the effluent of variable matrices (such as textile effluent, pharmaceutical industry effluent, food industry effluent) - Presents the application of doped semiconductors in the degradation of dyes, hybrid systems and their importance in the dye degradation - Describes the biological synthesis of metallic nanostructures and their use in dye degradation using visible range of light irradiation - Discusses the mechanistic aspect of the dye degradation using photo catalysts

Download or read book Photocatalytic Activity Enhancement of Titanium Dioxide Nanoparticles written by Mohamed A. Barakat and published by Springer. This book was released on 2015-10-26 with total page 39 pages. Available in PDF, EPUB and Kindle. Book excerpt: In this brief, a comprehensive review of the UV/visible-TiO2 photocatalytic oxidation process is presented with an insight into the mechanisms involved, the role of titanium dioxide as a catalyst, irradiation sources, types of reactors, and a comparison between various modes of TiO2 application. An overview of the development and enhancement of the activity of TiO2 nanoparticles in photocatalysis is presented. The topics covered include a detailed look at the unique properties of the TiO2 nanoparticles and their relationship to photocatalytic properties. The utilization of the TiO2 nanoparticles as photocatalysts, in the non-doped and doped forms is also reviewed. Finally, the use of modified TiO2 nanoparticles has made a significant contribution in providing definitive mechanistic information regarding the visible light photocatalytic processes.

Download or read book Development of Novel Visible and Solar Light activated Nanostructured Nitrogen fluorine Titanium Dioxide Photocatalyst for the Removal of Cyanotoxins in Water written by Miguel Pelaez and published by . This book was released on 2012 with total page 203 pages. Available in PDF, EPUB and Kindle. Book excerpt: The prevalent and increasing occurrence of cyanobacteria and their toxins, known as cyanotoxins, in drinking water sources have become a potential health risk to humans. Physical treatment methods in conventional drinking water treatment have the capacity to remove cyanotoxins but are limited to a merely physical separation, where further treatment is required. Cyanotoxins are susceptible to chemical oxidation and recently advanced oxidation technologies (AOTs) and nanotechnologies (AONs), such as titanium dioxide (TiO2) photocatalysis, have been proven an effective alternative technology to chemically transform cyanotoxins in water. However, conventional TiO2 is restricted to UV light photoactivation for the generation of highly reactive oxygen species (i.e., hydroxyl radicals) representing an economical and technological limitation for the use of renewable energy sources such as solar light, since UV radiation accounts only for 5% of the total solar spectrum compared to the visible spectrum (~45%). This dissertation explored the development of nanostructured nitrogen and fluorine co-doped TiO2 (NF-TiO2) that can be activated under visible and solar light for the photocatalytic degradation of cyanotoxins in water. This work aimed to develop highly efficient NF-TiO2 nanoparticles and films to evaluate the environmental fate of microcystins, the most widespread and highly persistent group of cyanotoxins found in surface waters, and cylindrospermopsin which has emerged as the most significant toxin in freshwater sources. Specific attention was given to 1) the fundamental aspects on the synthesis method that influenced the physicochemical properties of NF-TiO2, such as the incorporation of nitrogen and fluorine in the structure of TiO2 and the synergistic effects induced by both dopants, 2) the surface interaction between the cyanotoxins and NF-TiO2 in different water matrix, 3) the reactivity and degradation kinetics of microcystins and cylindrospermopsin with NF-TiO2 and 4) the mechanism of radical formation with NF-TiO2 under visible and solar light. The existence of interstitial nitrogen and substitutional fluorine in the NF-TiO2 lattice was determined and the formation of localized intra-gap states was established implying that fluorine promotes nitrogen incorporation in TiO2. A shift in the absorbance capacity of NF-TiO2 in the visible range was also observed. Anatase/brookite heterojunctions, which promote photocatalytic efficiency, were found in NF-TiO2. High initial degradation rates for microcystin-LR (MC-LR) were obtained with NF-TiO2 nanoparticles and films in synthetic water under visible light. The effect of pH indicated that attractive forces at acidic conditions between the oppositely charged NF-TiO2 and MC-LR contributed to higher MC-LR initial degradation rates. The presence of alkalinity and natural organic matter had a scavenging effect since the initial MC-LR degradation rates decreased. Modifications to NF-TiO2 with Evonik Aeroxide P25-TiO2 (P25) nanoparticles lead to composite NF-TiO2-P25 with improved photocatalytic activity towards MC-LR, MC-RR, MC-YR, MC-LA and cylindrospermopsin under visible and UV-vis light. The general reactivity was MC-LA>MC-LR>MC-YR>MC-RR. Finally, results using selected scavengers indicate that the main mechanism of NF-TiO2 radical formation under visible light irradiation differed from UV-mediated TiO2 photocatalysis since no evidence of hydroxyl radical production from the surface holes was observed. It was suggested that under visible light, surface oxygen reduction of NF-TiO2 occurred to form superoxide radical anion as main radical specie. The affinity of the scavenger with NF-TiO2 and MC-LR in terms of pH was established as an important parameter to determine the radicals formed in this study.

Download or read book Groundwater Chemicals Desk Reference written by John H. Montgomery and published by CRC Press. This book was released on 2007-04-18 with total page 1746 pages. Available in PDF, EPUB and Kindle. Book excerpt: Building on the foundation set by its best-selling predecessors, the Groundwater Chemicals Desk Reference, Fourth Edition is both a broad, comprehensive desk reference and a guide for field research. This fourth edition contains more than 1,700 additional references, including adsorption data for more than 800 organic compounds and metals, s

Download or read book Intelligent Biotechnologies of Natural and Synthetic Biologically Active Substances written by Vladimir Kurchenko and published by Springer Nature. This book was released on 2022-02-24 with total page 303 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book contains articles on innovative biotechnologies for the production and application of biopolymers and their derivatives in various industries. The conference “Intelligent Biotechnologies of Natural and Synthetic Biologically Active Substances: XIII Narochanskie Readings” took place on the base of Belarussian State University (Republic of Belarus, Minsk) and North Caucasus Federal University (Russian Federation, Stavropol) on December 1–3, 2021. The general scope of the book is current issues of biologically active substances (BAS) recovery and preparation methods development and their application in medicine, pharmaceutics, and functional nutrition. A number of original articles are devoted to the actual problems of BAS obtaining and application. A significant part of articles is related to the production of BAS nanocomplexes. Much attention is paid to promising areas of healthy foods biotechnology development and food safety. The book intends to readership specializing in the field of searching for new sources of BAS for their practical use in the framework of innovative pharmaceuticals and functional foods development

Download or read book Trends and Contemporary Technologies for Photocatalytic Degradation of Dyes written by Sushma Dave and published by Springer Nature. This book was released on 2022-09-29 with total page 287 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book looks at the recent developments in the area of photocatalytic degradation of dyes using photocatalytic techniques, for example by means of various nanoparticles, heterogeneous, and hybrid systems. Dyes are one of the major groups of water pollutants and are widely used in a diverse range of industries. The toxic effects of organic dyes in wastewater can have a great environmental impact, therefore there is significant interest and need to remove these dyes effectively and efficiently during wastewater treatment. This volume covers a plethora of basics on the photochemistry of dyes and provides information on technological perspectives including reactor designs and process intensification. Since many industries release a significant amount of colored effluents, which are toxic and difficult to remove by conventional methods, the comprehensive studies herein will contribute to helping reduce the impact of colored effluents in wastewater on the environment.

Download or read book Nanostructured Titanium Dioxide Materials written by Ali Reza Khataee and published by World Scientific. This book was released on 2012 with total page 205 pages. Available in PDF, EPUB and Kindle. Book excerpt: During the past decade, research and development in the area of synthesis and applications of different nanostructured titanium dioxide have become tremendous. This book briefly describes properties, production, modification and applications of nanostructured titanium dioxide focusing in particular on photocatalytic activity. The physicochemical properties of nanostructured titanium dioxide are highlighted and the links between properties and applications are emphasized. The preparation of TiO2 nanomaterials, including nanoparticles, nanorods, nanowires, nanosheets, nanofibers, and nanotubes are primarily categorized by their preparation method (sol-gel and hydrothermal processes). Examples of early applications of nanostructured titanium dioxide in dye-sensitized solar cells, hydrogen production and storage, sensors, rechargeable batteries, electrocatalysis, self-cleaning and antibacterial surfaces and photocatalytic cancer treatment are reviewed. The review of modifications of TiO2 nanomaterials is mainly focused on the research related to the modifications of the optical properties of TiO2 nanomaterials, since many applications of TiO2 nanomaterials are closely related to their optical properties. Photocatalytic removal of various pollutants using pure TiO2 nanomaterials, TiO2-based nanoclays and non-metal doped nanostructured TiO2 are also discussed.

Download or read book Photochemical Purification of Water and Air written by Thomas Oppenländer and published by John Wiley & Sons. This book was released on 2007-06-27 with total page 383 pages. Available in PDF, EPUB and Kindle. Book excerpt: While the treatment of water and exhaust gas using ultraviolet (UV) light offers both ecological and economic advantages, information on photo-initiated advanced oxidation technologies (AOTs) has been dispersed among various journals and proceedings until now. This authoritative and comprehensive handbook is the first to cover both the photochemical fundamentals and practical applications, including a description of advanced oxidation processes (AOPs) and process engineering of suitable photoreactors. The author presents various real-world examples, including economic aspects, while many references to current scientific literature facilitate access to current research topics relevant for water and air industries. Throughout, over 140 detailed figures visualize photochemical and photophysical phenomena, and help in interpreting important research results. From the foreword by James R. Bolton (President of Bolton Photosciences Inc., Executive Director of the International Ultraviolet Association (IUVA)): "Prof. Oppenländer is well qualified to write about the AOPs/AOTs, since he has contributed to this literature in a very significant manner. This book will be of considerable value to graduate students, science and engineering faculty, scientists, process engineers and sales engineers in industry, government regulators and health professionals."

Download or read book Photon Involving Purification of Water and Air written by Pierre Pichat and published by MDPI. This book was released on 2018-03-05 with total page 325 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book is a printed edition of the Special Issue "Photon-involving Purification of Water and Air" that was published in Molecules

Download or read book Photocatalysts for Organics Degradation written by Barbara Bonelli and published by MDPI. This book was released on 2020-06-23 with total page 98 pages. Available in PDF, EPUB and Kindle. Book excerpt: The quality of water is not only a technological and scientific issue, but a social and economic problem, in both developed and developing countries. Besides local regulations, which differ between regions and need constant upgrades, significant scientific developments are required in both the detection and removal of water contaminants. This Issue focuses on some recent advancements in the photocatalytic removal of organic pollutants, which is one of the aspects of the problem that involves the need of advanced catalysts and implies significant advancements in the field of materials science and chemical engineering.

Download or read book Russian Journal of General Chemistry written by and published by . This book was released on 1997 with total page 520 pages. Available in PDF, EPUB and Kindle. Book excerpt: