Author: Chen-Yung Hsiao
Publisher:
ISBN:
Category :
Languages : en
Pages : 130

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Book Description

Author: Chen-Yung Hsiao
Publisher:
ISBN:
Category :
Languages : en
Pages : 150

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Book Description

Author: Martin M. Halmann
Publisher: CRC Press
ISBN: 9780849324598
Category : Technology & Engineering
Languages : en
Pages : 322

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Book Description
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.

Author: Wonyong Choi
Publisher:
ISBN:
Category : Electronic dissertations
Languages : en
Pages : 328

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Author: Khaled M. Mezughi
Publisher:
ISBN:
Category :
Languages : en
Pages : 212

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Book Description
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.

Author: National Research Council
Publisher: National Academies Press
ISBN: 0309045762
Category : Science
Languages : en
Pages : 90

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Book Description
This book reviews current work and assesses the state of the art in potential applications of concentrated solar energy in nonelectric areas, such as water and waste treatment, photochemical processes, and materials processing. It identifies and recommends research needed for further development of promising applications.

Author: American Society of Mechanical Engineers. Solar Energy Division. Conference
Publisher:
ISBN:
Category : Solar energy
Languages : en
Pages : 448

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Book Description

Author: Nick Serpone
Publisher: Wiley-Interscience
ISBN:
Category : Science
Languages : en
Pages : 680

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Book Description
Contributors from around the world offer wide-ranging (and sometimes controversial) discussions of the state of research in photocatalysis. Emphasis is on the surface science of catalysis, especially at the gas/solid interface. Eighteen chapters explore topics ranging from the interaction between light and matter, colloidal semiconductors, and the thermodynamics and kinetics of photocatalysis, to photocatalysis in homogeneous and heterogeneous phases, photo-electrocatalysis, and catalysis in energy production and water purification.

Author: Simon Parsons
Publisher: IWA Publishing
ISBN: 1843390175
Category : Science
Languages : en
Pages : 370

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Book Description
The suitability of Advanced Oxidation Processes (AOPs) for pollutant degradation was recognised in the early 1970s and much research and development work has been undertaken to commercialise some of these processes. AOPs have shown great potential in treating pollutants at both low and high concentrations and have found applications as diverse as ground water treatment, municipal wastewater sludge destruction and VOCs control. Advanced Oxidation Processes for Water and Wastewater Treatment is an overview of the advanced oxidation processes currently used or proposed for the remediation of water, wastewater, odours and sludge. The book contains two opening chapters which present introductions to advanced oxidation processes and a background to UV photolysis, seven chapters focusing on individual advanced oxidation processes and, finally, three chapters concentrating on selected applications of advanced oxidation processes. Advanced Oxidation Processes for Water and Wastewater Treatment will be invaluable to readers interested in water and wastewater treatment processes, including professionals and suppliers, as well as students and academics studying in this area. Dr Simon Parsons is a Senior Lecturer in Water Sciences at Cranfield University with ten years' experience of industrial and academic research and development.

Author: Krishnan Rajeshwar
Publisher:
ISBN: 9780125762601
Category : Science
Languages : en
Pages : 776

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Book Description
The first book of its kind, Environmental Electrochemistry considers the role that electrochemical science and engineering can play in environmental remediation, pollution targeting, and pollutant recycling. Electrochemical-based sensors and abatement technologies for the detection, quantification, and treatment of environmental pollutants are described. Each chapter includes an extensive listing of supplemental readings, with illustrations throughout the bookto clarify principles and approaches detailed in the text. Key Features * The first book to review electro- and photoelectrochemical technologies for environmental remediation, pollution sensors and pollutant recycling * Applicable to a broad audience of environmental scientists and practicing electrochemists * Includes both laboratory concepts and practical applications