The Photodegradation of 2-chlorophenol in Aqueous TiO2 Suspensions

The Photodegradation of 2-chlorophenol in Aqueous TiO2 Suspensions PDF Author: Chih-Chang Wang
Publisher:
ISBN:
Category : Chlorophenols
Languages : en
Pages : 230

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The Photodegradation of 2-chlorophenol in Aqueous TiO2 Suspensions

The Photodegradation of 2-chlorophenol in Aqueous TiO2 Suspensions PDF Author: Chih-Chang Wang
Publisher:
ISBN:
Category : Chlorophenols
Languages : en
Pages : 230

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Aspects of the Heterogeneous Photocatalytic Degradation of Organic Pollutants in Water

Aspects of the Heterogeneous Photocatalytic Degradation of Organic Pollutants in Water PDF Author: Laurence Timothy Hogg
Publisher:
ISBN:
Category :
Languages : en
Pages : 151

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Book Description
The photo-activity and specific surface area of a number of potentially-useful photocatalysts has been determined using the liquid phase dehydrogenation of propan-2-ol (activity), and the adsorption of argon gas at 77K (surface area). Degussa P25 titanium dioxide was considered the most active solid on this basis (activity=l23_+5xl0-4mol.g-1h-1, SA 39_+3 m2g-1). The photo-activity of suspended solids was found to be dependent upon the anatase:rutile ratio and the catalyst concentration, but relatively independent of the surface area for structurally different specimens. This has been explained in terms of the absorbance of band-gap radiation by the solid as a function of suspended particulate mass. Experimental evidence regarding the rate of propan-2-ol photo-oxidation under oxygen-purged conditions compared to the observed rate under air, suggests a rate dependence upon the partial pressure of oxygen of P02 1/2 The total photocatalytic mineralisation of aqueous 2-chlorophenol mediated by Degussa P25 TiO2 has been achieved in approximately 5 hours (c0 2CP = 5x10-4M), with an initial zero order rate constant of 1.7x10-4mol.g-1h-1. (6h irradiation period). The kinetics of the reaction are shown to be loosely expressed by the Langmuir-Hinshelwood kinetic model, but complex kinetics were in evidence under conditions of partial mineralisation, which may be dictated by the solution pH and/or the concentration of intermediate degradation products. A mechanism for the photo-oxidation reaction has also been proposed, based upon experimental evidence involving measurements of pH, conductance, carbon dioxide evolution and GCMS studies, which suggests a complex reaction pathway. The photocatalytic mineralisation of a saturated solution of gamma - hexachlorocyclohexane (Lindane, 7ppm), has been achieved in approximately 2 hours by this method and the mechanistic and kinetic details of this reaction are discussed briefly.

Photodegradation of Water Pollutants

Photodegradation of Water Pollutants PDF Author: Martin M. Halmann
Publisher: CRC Press
ISBN: 1040286240
Category : Technology & Engineering
Languages : en
Pages : 319

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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.

A Statistical Evaluation of the Photocatalytic Degradation of 3-chlorophenol in Aqueous Solution Using UV Light and TiO2

A Statistical Evaluation of the Photocatalytic Degradation of 3-chlorophenol in Aqueous Solution Using UV Light and TiO2 PDF Author: Shinoka Fujita
Publisher:
ISBN:
Category : Water
Languages : en
Pages : 388

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Photochemistry

Photochemistry PDF Author: A. Gilbert
Publisher: Royal Society of Chemistry
ISBN: 0854044051
Category : Reference
Languages : en
Pages : 418

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Book Description
The breadth of scientific and technological interests in the general topic of photochemistry is truly enormous and includes, for example, such diverse areas as microelectronics, atmospheric chemistry, organic synthesis, non-conventional photoimaging, photosynthesis, solar energy conversion, polymer technologies, and spectroscopy. This Specialist Periodical Report on Photochemistry aims to provide an annual review of photo-induced processes that have relevance to the above wide-ranging academic and commercial disciplines, and interests in chemistry, physics, biology and technology. In order to provide easy access to this vast and varied literature, each volume of Photochemistry comprises sections concerned with photophysical processes in condensed phases, organic aspects which are sub-divided by chromophore type, polymer photochemistry, and photochemical aspects of solar energy conversion. Volume 34 covers literature published from July 2001 to June 2002. Specialist Periodical Reports provide systematic and detailed review coverage in major areas of chemical research. Compiled by teams of leading authorities in the relevant subject areas, the series creates a unique service for the active research chemist, with regular, in-depth accounts of progress in particular fields of chemistry. Subject coverage within different volumes of a given title is similar and publication is on an annual or biennial basis.

Aquatic and Surface Photochemistry

Aquatic and Surface Photochemistry PDF Author: George R. Helz
Publisher: CRC Press
ISBN: 1351078291
Category : Science
Languages : en
Pages : 571

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Book Description
Aquatic and Surface Photochemistry provides a broad overview of current research in the emerging field of environmental aquatic and surface photochemistry. Selected reviews and current research articles are blended to provide an in-depth treatment of various aspects of this research area. The first part of the text deals with photochemistry in the environment, covering recent research on the following topics: aquatic photochemistry of organic pollutants and agrochemicals, photochemical cycling of carbon and transition metals (especially iron), photochemical formation of reactive oxygen species in natural waters, photoreaction in cloud and rain droplets, and photoreactions on environmental surfaces (soil, ash, metal, oxide). The second part provides discussions and data on both heterogeneous photocatalytic and homogeneous processes, with topics ranging from applications to mechanistic studies. These chapters illustrate the wide diversity of pollutant classes that are degradable by photochemical techniques and the effects of various reaction conditions on the rates and efficiency of the techniques. Current kinetic studies are presented, which provide new information about the role of adsorption and the nature of the reactive oxidizing species that mediate these photoremediation processes.This book will interest civil, chemical, and environmental engineers, as well as chemists, soil scientists, geochemists, and atmospheric chemists.

Hazardous and Industrial Waste Proceedings, 27th Mid-Atlantic Conference

Hazardous and Industrial Waste Proceedings, 27th Mid-Atlantic Conference PDF Author: Arup K. SenGupta
Publisher: CRC Press
ISBN: 9781566763578
Category : Science
Languages : en
Pages : 978

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Proceedings of the Third Asia-Pacific Conference on Sustainable Energy and Environmental Technologies, Hong Kong, 3-6 December 2000

Proceedings of the Third Asia-Pacific Conference on Sustainable Energy and Environmental Technologies, Hong Kong, 3-6 December 2000 PDF Author: Xijun Hu
Publisher: World Scientific
ISBN: 9789810245498
Category : Science
Languages : en
Pages : 716

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Book Description
With the rapid expansion of the Asia-Pacific economy in the last decade and the recovery after the recent crisis, severe demands will be placed on energy services and the environment. Coping with the volatile oil prices that persist in the market introduces an additional factor into the energy supply and demand equation, not just for countries in this region but also worldwide. Inevitably there will be implications for environmental issues too. The future will see a continuing challenge to balance growth with sustainability in the economic, social and environmental sectors. This conference, a sequel to the immensely successful APCSEET conferences held in Singapore and Australia, is aimed at meeting that challenge by addressing the pertinent issues related to sustainable energy and environmental protection. It provides a forum for participants from academia, industry and government agencies to interact, report on research in progress, and identify opportunities in the fields of sustainable energy and environmental technologies. The presentations include not only technical issues such as air pollution control, wastewater treatment, solid waste management, renewable energy and cleaner production, but also education and policy issues.

Process Engineering for Pollution Control and Waste Minimization

Process Engineering for Pollution Control and Waste Minimization PDF Author: Donald L. Wise
Publisher: CRC Press
ISBN: 9781420061765
Category : Science
Languages : en
Pages : 750

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Book Description
Offers up-to-date technical information on current and potential pollution control and waste minimization practices, providing industry-specific case studies, techniques and models.

Applied Photochemistry

Applied Photochemistry PDF Author: Rachel C. Evans
Publisher: Springer Science & Business Media
ISBN: 9048138302
Category : Science
Languages : en
Pages : 619

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Book Description
Applied Photochemistry encompasses the major applications of the chemical effects resulting from light absorption by atoms and molecules in chemistry, physics, medicine and engineering, and contains contributions from specialists in these key areas. Particular emphasis is placed both on how photochemistry contributes to these disciplines and on what the current developments are. The book starts with a general description of the interaction between light and matter, which provides the general background to photochemistry for non-specialists. The following chapters develop the general synthetic and mechanistic aspects of photochemistry as applied to both organic and inorganic materials, together with types of materials which are useful as light absorbers, emitters, sensitisers, etc. for a wide variety of applications. A detailed discussion is presented on the photochemical processes occurring in the Earth’s atmosphere, including discussion of important current aspects such as ozone depletion. Two important distinct, but interconnected, applications of photochemistry are in photocatalytic treatment of wastes and in solar energy conversion. Semiconductor photochemistry plays an important role in these and is discussed with reference to both of these areas. Free radicals and reactive oxygen species are of major importance in many chemical, biological and medical applications of photochemistry, and are discussed in depth. The following chapters discuss the relevance of using light in medicine, both with various types of phototherapy and in medical diagnostics. The development of optical sensors and probes is closely related to diagnostics, but is also relevant to many other applications, and is discussed separately. Important aspects of applied photochemistry in electronics and imaging, through processes such as photolithography, are discussed and it is shown how this is allowing the increasing miniaturisation of semiconductor devices for a wide variety of electronics applications and the development of nanometer scale devices. The final two chapters provide the basic ideas necessary to set up a photochemical laboratory and to characterise excited states. This book is aimed at those in science, engineering and medicine who are interested in applying photochemistry in a broad spectrum of areas. Each chapter has the basic theories and methods for its particular applications and directs the reader to the current, important literature in the field, making Applied Photochemistry suitable for both the novice and the experienced photochemist.