Download or read book Photochemical Investigations of Surface Adsorbed Polycyclic Aromatic Hydrocarbons written by Anthony Dewayne Hipps and published by . This book was released on 1989 with total page 144 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Photochemical Investigation of Polycyclic Aromatic Hydrocarbons Vapor adsorbed on Coal Fly Ash written by Robert Jay Engelbach and published by . This book was released on 1986 with total page 282 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Phototransformation of Polycyclic Aromatic Hydrocarbons PAHs on a Non Semi Conductive Surface Such as Silica written by and published by . This book was released on 1997 with total page 15 pages. Available in PDF, EPUB and Kindle. Book excerpt: Polycyclic aromatic hydrocarbons (PAH), by products of fossil fuel production and consumption, constitute a large class of environmental pollutants. These toxic and sometimes carcinogenic compounds are also found in coal tar and fly ash. When released into the air, they can be sorbed onto particulates present in the atmosphere where they find their way into soil and ground water upon being washed by rain. During their residence time in the environment, PAHs will be exposed to solar radiation and may undergo phototransformation to other products. Thus, light induced photodegradation of PM's at the solid/air interfaces can play a significant role in their depletion. Light-induced processes have been claimed to enhance transformation of these PM's in the environment. However, detailed studies on the nature and identities of photoproducts formed during the transformation of these compounds on solid surfaces is scarce. Since insulators such as silica, alumina, silicoaluminates and calcium carbonate are believed to constitute up 20-30% of inorganic particulates present in the atmosphere, they serve as environmentally relevant model surfaces to study the photophysical and photochemical behavior of PM's. Although photochemistry of organic compounds adsorbed on solid surfaces has received much attention in recent years, the specific properties of the interface which influence photoprocesses and the exact mechanism of interaction between a surface and a substrate are often not well understood. We have investigated the photochemistry of many PAHs including eight that are on Environmental Protection Agency's (EPA) sixteen priority pollutant PAH list shown in Table 1 at silica/air interface.
Download or read book Toxicological Profile for Polycyclic Aromatic Hydrocarbons written by and published by . This book was released on 1995 with total page 500 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Photoinduced Degradation of PAHs in the Presence of Ozone written by and published by . This book was released on 1995 with total page 4 pages. Available in PDF, EPUB and Kindle. Book excerpt: Polycyclic Aromatic Hydrocarbons (PAH) are formed from both anthropogenic and natural sources. In order to assess the environmental impact caused by the surface-adsorbed PAHs, the chemical lifetimes of these compounds in the atmosphere must be determined. Although ozone is known to be a primary reactant in the chemical transformation of surface-adsorbed PAHs in the atmosphere, the kinetics of these reactions have not been investigated in detail. In addition to the experimental difficulties that arise in using an oxygen-ozone stream while monitoring the PAH with fluorescence, complications in analyzing the kinetic mechanism also exist. It is difficult to determine whether the ozone or oxygen initially quenches the excited state of PAH. Ozone could enhance the degradation rate by simply reacting with a product derived from the excited state of PAH and oxygen. The focus of this study is to demonstrate the use of fluorescence spectroscopy in monitoring the degradation of PAH adsorbed on a three dimensional particle in the presence of gaseous ozone free from the interference of oxygen. More specifically, the experimental procedure will involve the generation of an ozone-nitrogen gas stream to be used in the investigation of dark and photochemical reactions between ozone and naphthalene. The absence of oxygen in the system will allow for the accurate monitoring of PAH fluorescence decay due solely to ozone quenching. It will also aid in the determination of the reaction mechanism. This is the first time that the direct interaction of ozone with an excited state of PAH has been demonstrated.
Download or read book Photochemical and Supercritical Fluid Extraction Studies of Polycyclic Aromatic Hydrocarbons Adsorbed on Coal Stack Ash Fractions written by Robert Frank Mauldin and published by . This book was released on 1990 with total page 238 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Chemical Interactions of Polycyclic Organic Compounds with Coal Fly Ash and Related Solid Surfaces written by and published by . This book was released on 1990 with total page 13 pages. Available in PDF, EPUB and Kindle. Book excerpt: The interactions of polycyclic aromatic hydrocarbons (PAHs) with particulate surfaces (especially those of coal fly ash) have been investigated, and the influence of coal ash surface properties on the photochemical transformation of adsorbed PAHs has been studied. The overall objective of the work has been to characterize the effects of adsorption onto atmospheric particulate matter on the chemical behavior of PAHs released into the atmosphere via combustion processes. Progress is reported in the following areas of effort: (a) Major emphasis has been devoted to the interactions of PAHs with the different particulate phases that are found in heterogeneous coal ash samples. Techniques have been developed and thoroughly characterized for the fractionation of coal ashes into carbonaceous, mineral-magnetic, and mineral-nonmagnetic subfractions. Heats of adsorption for pyrene on such subfractions have been measured by gas-solid chromatography, and the photoreactivity of pyrene and benz[a]anthracene on ash subfractions has been examined. Carbonaceous particles exhibit the highest affinity for vapor-phase PAHS; mineral magnetic particles usually exhibit the smallest tendency to sorb PAHs from the vapor phase. Adsorption of PAHs on carbonaceous particles suppresses, virtually completely, their tendency to undergo photochemical transformation. For coal ashes that contain few carbonaceous particles, the adsorption and photochemical transformation of PAHs tend to be dominated by the mineral nonmagnetic particles; PAHs adsorbed on these particles tend to exhibit relatively efficient phototransformation.
Download or read book Photochemical Reaction Products of Polycyclic Aromatic Hydrocarbons Adsorbed at an Air water Interface written by Franz Stefan Ehrenhauser and published by . This book was released on 2011 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Adsorption and Photochemical Transformation of Polycyclic Aromatic Hydrocarbons on Atmospheric Water Films written by Jing Chen and published by . This book was released on 2008 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book The Photophysics of Polycyclic Aromatic Hydrocarbons Adsorbed on Silica Gel Surfaces microform a Lifetime Distribution Analysis Approach written by Yuan-Sheng Liu and published by National Library of Canada = Bibliothèque nationale du Canada. This book was released on 1991 with total page 252 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Aromatic Polycyclic Hydrocarbons Advances in Research and Application 2011 Edition written by and published by ScholarlyEditions. This book was released on 2012-01-09 with total page 201 pages. Available in PDF, EPUB and Kindle. Book excerpt: Aromatic Polycyclic Hydrocarbons: Advances in Research and Application: 2011 Edition is a ScholarlyEditions™ eBook that delivers timely, authoritative, and comprehensive information about Aromatic Polycyclic Hydrocarbons. The editors have built Aromatic Polycyclic Hydrocarbons: Advances in Research and Application: 2011 Edition on the vast information databases of ScholarlyNews.™ You can expect the information about Aromatic Polycyclic Hydrocarbons in this eBook to be deeper than what you can access anywhere else, as well as consistently reliable, authoritative, informed, and relevant. The content of Aromatic Polycyclic Hydrocarbons: Advances in Research and Application: 2011 Edition has been produced by the world’s leading scientists, engineers, analysts, research institutions, and companies. All of the content is from peer-reviewed sources, and all of it is written, assembled, and edited by the editors at ScholarlyEditions™ and available exclusively from us. You now have a source you can cite with authority, confidence, and credibility. More information is available at http://www.ScholarlyEditions.com/.
Download or read book Polycyclic Aromatic Hydrocarbons in Water Sys written by David J. Futoma and published by Springer. This book was released on 1981-11-05 with total page 208 pages. Available in PDF, EPUB and Kindle. Book excerpt: Opisane so spektroskopske in kromatografske analize PAH v vodi, njihova topnost, vzorčevanje in predhodno koncentriranje.
Download or read book Chemical Interactions of Polycyclic Organic Compounds with Coal Fly Ash and Related Solid Surfaces Final Report July 1 1987 December 31 1989 written by and published by . This book was released on 1990 with total page 13 pages. Available in PDF, EPUB and Kindle. Book excerpt: The interactions of polycyclic aromatic hydrocarbons (PAHs) with particulate surfaces (especially those of coal fly ash) have been investigated, and the influence of coal ash surface properties on the photochemical transformation of adsorbed PAHs has been studied. The overall objective of the work has been to characterize the effects of adsorption onto atmospheric particulate matter on the chemical behavior of PAHs released into the atmosphere via combustion processes. Progress is reported in the following areas of effort: (a) Major emphasis has been devoted to the interactions of PAHs with the different particulate phases that are found in heterogeneous coal ash samples. Techniques have been developed and thoroughly characterized for the fractionation of coal ashes into carbonaceous, mineral-magnetic, and mineral-nonmagnetic subfractions. Heats of adsorption for pyrene on such subfractions have been measured by gas-solid chromatography, and the photoreactivity of pyrene and benz[a]anthracene on ash subfractions has been examined. Carbonaceous particles exhibit the highest affinity for vapor-phase PAHS; mineral magnetic particles usually exhibit the smallest tendency to sorb PAHs from the vapor phase. Adsorption of PAHs on carbonaceous particles suppresses, virtually completely, their tendency to undergo photochemical transformation. For coal ashes that contain few carbonaceous particles, the adsorption and photochemical transformation of PAHs tend to be dominated by the mineral nonmagnetic particles; PAHs adsorbed on these particles tend to exhibit relatively efficient phototransformation.
Download or read book PAHs written by Peter E. T. Douben and published by John Wiley & Sons. This book was released on 2003-07-25 with total page 404 pages. Available in PDF, EPUB and Kindle. Book excerpt: Polycyclic aromatic hydrocarbons (PAHs), or polyarenes, are one of the largest and most structurally diverse class of organic molecules known. High percentages of polyarenes, representing a wide range of molecular sizes and structural types, are present in coal tars and petroleum residues. The major sources of PAHs are crude oil, coal and oil shale. The fuels produced from these fossil sources constitute the primary source of energy for the industrial nations of the world, and the petrochemicals from these raw materials are the basis of the synthetic fibre and plastics industries. PAHs are however, widespread pollutants and their impact on the environment and human health must be monitored and controlled. This book will review and assess our scientific understanding of the ecological exposure and effects PAHs have in different environments and habitats. It will accomplish this by taking the recipients of the pollution in the environment as starting points and working its way back through pathways to access what is required for our understanding of effects and rationale for control. Although this book will concentrate on ecological exposure of PAHs, the general impacts of PAHs on human populations will be touched upon. It is thought to be the first book to focus on the ecological aspects of PAHs.
Download or read book Aquatic and Surface Photochemistry written by George R. Helz and published by CRC Press. This book was released on 2018-01-10 with total page 571 pages. Available in PDF, EPUB and Kindle. Book excerpt: 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.
Download or read book The Aromatic Sextet written by Erich Clar and published by John Wiley & Sons. This book was released on 1972 with total page 144 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Polycyclic Aromatic Hydrocarbons in the Aquatic Environment written by and published by . This book was released on 1983 with total page 232 pages. Available in PDF, EPUB and Kindle. Book excerpt:
