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Photochemistry Of Dissolved Natural Organic Matter And Its Interactions With Methylmercury And Inorganic Mercury
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Book Synopsis Photochemistry of Dissolved Natural Organic Matter and Its Interactions with Methylmercury and Inorganic Mercury by : Abdul Rafi Khwaja
Download or read book Photochemistry of Dissolved Natural Organic Matter and Its Interactions with Methylmercury and Inorganic Mercury written by Abdul Rafi Khwaja and published by . This book was released on 2004 with total page 454 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Water Chemistry by : Patrick L. Brezonik
Download or read book Water Chemistry written by Patrick L. Brezonik and published by Oxford University Press. This book was released on 2022-06-15 with total page 977 pages. Available in PDF, EPUB and Kindle. Book excerpt: Water Chemistry provides students with the tools needed to understand the processes that control the chemical species present in waters of both natural and engineered systems. After providing basic information about water and its chemical composition in environmental systems, the text covers theoretical concepts key to solving water chemistry problems. Water Chemistry emphasizes that both equilibrium and kinetic processes are important in aquatic systems. The content focuses not only on inorganic constituents but also on natural and anthropogenic organic chemicals in water. This new edition of Water Chemistry also features updated discussions of photochemistry, chlorine and disinfectants, geochemical controls on chemical composition, trace metals, nutrients, and oxygen. Quantitative equilibrium and kinetic problems related to acid-base chemistry, complexation, solubility, oxidation/reduction reactions, sorption, and the fate and reactions of organic chemicals are solved using mathematical, graphical, and computational tools. Examples show the application of theory and demonstrate how to solve problems using algebraic, graphical, and up-to-date computer-based techniques. Additional web material provides advanced content.
Book Synopsis Surface Water Photochemistry by : Paola Calza
Download or read book Surface Water Photochemistry written by Paola Calza and published by Royal Society of Chemistry. This book was released on 2015-11-20 with total page 310 pages. Available in PDF, EPUB and Kindle. Book excerpt: Borne out of the current widespread interest in the pollution of water bodies, this book explores the latest research concerning the photochemical fate of organic pollutants in surface water. The main objective is to give insight into both the functioning of ecosystems and the behaviour of emerging pollutants in those ecosystems. Particular importance is dedicated to techniques that can be used in the field and in the laboratory for the detection of pollutants and of their transformation intermediates. The inclusion of photochemical processes that have not gained previous coverage will afford the reader novel insights, whilst the focus on modelling and transformation intermediates will ensure the title's relevance to academics, the chemical manufacturing industries and environmental assessment experts alike.
Book Synopsis Influence of the Composition and Character of Dissolved Organic Matter (DOM) on the Removal of Mercury from Surface Water in Metal Based-coagulation Systems by : Farith Adilson Díaz Arriaga
Download or read book Influence of the Composition and Character of Dissolved Organic Matter (DOM) on the Removal of Mercury from Surface Water in Metal Based-coagulation Systems written by Farith Adilson Díaz Arriaga and published by . This book was released on 2018 with total page 358 pages. Available in PDF, EPUB and Kindle. Book excerpt: According to The United Nations Environment Programme (UNEP), mercury pollution still represents a major threat to human health and the environment, mainly in regions where metallic mercury (Hg0) is used to extract gold or where coal burning increases the emissions of mercury in the atmosphere. In the particular case of the metallic mercury used in artisanal and small-scale gold mining (ASGM), there is substantial evidence about the direct impact of mercury on human health, mainly due to the inhalation of vapor mercury and the intake of fish with high levels of methylmercury (MeHg). Once metallic mercury is dumped into rivers and soils, this pollutant can react with sulfur reduced ligands in sediments or can be converted to Hg(II) and it will interact with dissolved organic matter (DOM) in aquatic environments. Such interaction will control the fate of this pollutant in water, as well as its toxicity and mobility downstream rivers. Accordingly, these Hg-DOM interactions will also control the ability to remove this pollutant during water treatment. This research shows that out, of the different functional groups present in dissolved organic matter, reduced sulfur ligands (S [subscript red] ) play a key role in removing mercury from waters with low Hg/DOM ratio. This trend is particularly evident in waters with low in aromatic content (which translate to low DOC removal) and high concentrations of S [subscript red] ligands. At much higher mercury concentrations, once the S [subscript red] ligands are saturated with mercury, the carboxylic ligands control the removal of mercury from solution. Under these conditions, the removal of mercury is proportional to the removal of carbon (∼1:1 ratio) as all the Hg(II) ions are bound to the all the functional groups available for Hg(II) complexation, even binding weak ligands such as carboxylic acids. In all cases, it is necessary to provide optimal coagulation conditions (pH and coagulant dose) to effectively remove dissolved organic matter, and therefore associated mercury, from solution.
Book Synopsis Water Chemistry by : Patrick Brezonik
Download or read book Water Chemistry written by Patrick Brezonik and published by OUP USA. This book was released on 2011-03-22 with total page 809 pages. Available in PDF, EPUB and Kindle. Book excerpt: It emphasizes that both equilibrium and kinetic processes are important in aquatic systems.
Book Synopsis Photochemistry of Natural Organic Matter by : Ann Maurine McNally
Download or read book Photochemistry of Natural Organic Matter written by Ann Maurine McNally and published by . This book was released on 2006 with total page 270 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Dissolved Organic Matter Percolated from Periphyton in the Everglades: Characterization and Interaction with Mercury by : Afia Anjuman
Download or read book Dissolved Organic Matter Percolated from Periphyton in the Everglades: Characterization and Interaction with Mercury written by Afia Anjuman and published by . This book was released on 2017 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: When organic matters of various kinds decompose partially, dissolved or soluble organic matters can form. The organic matters are usually produced from plants, soil, bacteria, algae, and living organisms. The wetland of Everglades is rich in dissolved organic matters. The quantity and quality of these dissolved organic matters have significant impact on environmental factors such as biogeochemical activity, transport, absorption, complexation, and more specifically the speciation and geochemical cycling of toxic metals such as mercury (Hg). Everglades wetland is abundant in periphyton which can also be responsible for dissolved organic matter percolation and production. The DOM from periphyton, in particular when freshly produced and released into the water, would have a profound effect on mercury species present in the water, e.g., by forming mercury-DOM complexes. This experiment is designed to perform quantitative and qualitative analysis of DOM produced by periphyton and the complexation of mercury with the produced DOM from periphyton in molecular level. In addition to organic carbon analysis, the samples will be analyzed for optical properties by using a spectrofluorometer for information on the sources, types, and reactivity of DOM. Studies will be done with addition of inorganic and methyl mercury of different concentrations in leached DOM samples from different types of periphyton by observing fluorescence quenching for Hg-DOM complexation using 3D Excitation Emission Matrices Fluorescence Spectroscopy. Water samples from different types of periphyton will be differentiated by measuring different functional groups of DOM; such as total protein, carbohydrates, and thiols; including Chlorophyll-a and nutrients quantitatively using some standard protocols. Measurement of specific types of DOM from periphyton quantitatively will be performed by observing periphyton biomass response for interaction with mercury using Attenuated Total Reflectance-Fourier Transform Infrared Spectroscopy. The project will improve the understanding of the relation between DOM and periphyton and the environmental processes of Hg impacted by periphyton in the Florida Everglades.
Book Synopsis Linking Optical and Chemical Properties of Dissolved Organic Matter in Natural Waters by : Christopher L. Osburn
Download or read book Linking Optical and Chemical Properties of Dissolved Organic Matter in Natural Waters written by Christopher L. Osburn and published by Frontiers Media SA. This book was released on 2017-01-17 with total page 244 pages. Available in PDF, EPUB and Kindle. Book excerpt: A substantial increase in the number of studies using the optical properties (absorbance and fluorescence) of dissolved organic matter (DOM) as a proxy for its chemical properties in estuaries and the coastal and open ocean has occurred during the last decade. We are making progress on finding the actual chemical compounds or phenomena responsible for DOM’s optical properties. Ultrahigh resolution mass spectrometry, in particular, has made important progress in making the key connections between optics and chemistry. But serious questions remain and the last major special issue on DOM optics and chemistry occurred nearly 10 years ago. Controversies remain from the non-specific optical properties of DOM that are not linked to discrete sources, and sometimes provide conflicting information. The use of optics, which is relatively easier to employ in synoptic and high resolution sampling to determine chemistry, is a critical connection to make and can lead to major advances in our understanding of organic matter cycling in all aquatic ecosystems. The contentions and controversies raised by our poor understanding of the linkages between optics and chemistry of DOM are bottlenecks that need to be addressed and overcome.
Book Synopsis Photochemical Oxidation of Dissolved Elemental Mercury by Carbonate Radicals in Water by :
Download or read book Photochemical Oxidation of Dissolved Elemental Mercury by Carbonate Radicals in Water written by and published by . This book was released on 2014 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Photochemical oxidation of dissolved elemental mercury [Hg(0)] affects mercury chemical speciation and its transfer at the water-air interface in the aquatic environment. The mechanisms and factors that control Hg(0) photooxidation, however, are not completely understood, especially in natural freshwaters containing dissolved organic matter (DOM) and carbonate. Here, we evaluate Hg(0) photooxidation rates affected by various reactive ionic species [e.g., DOM, HCO3-, NO3-] and free radicals in a creek water and a phosphate buffer solution (pH=8) under simulated solar irradiation. We report a high Hg(0) photooxidation rate (k = 1.44 h-1) in the presence of both HCO3- and NO3-, whereas HCO3-, NO3-, or DOM alone increased the oxidation rate slightly (k = 0.1 0.17 h-1). Using scavengers and enhancers for singlet oxygen (1O2) and hydroxyl (HO) radicals, as well as electron paramagnetic resonance spectroscopy, we identify that carbonate radicals (CO3 - ) primarily drive the Hg(0) photooxidation, whereas addition of DOM resulted in a 2-fold decrease in Hg(0) oxidation. This study identifies an unrecognized pathway of Hg(0) photooxidation by CO3 - radicals and the inhibitory effect of DOM, which could be important in assessing Hg transformation and fate in water containing carbonate such as hard water and seawater.
Book Synopsis Ecology of Humic Substances in Freshwaters by : Christian Steinberg
Download or read book Ecology of Humic Substances in Freshwaters written by Christian Steinberg and published by Springer Science & Business Media. This book was released on 2013-11-11 with total page 441 pages. Available in PDF, EPUB and Kindle. Book excerpt: Humic Substances color all waters more or less brown. Their concentrations exceed all carbon of living organisms by at least one order of magnitude. Opposite to former paradigms, they participate in almost any metabolic pathway. They protect against UV-irradation, enable indirect photolysis and, thus, purify hazardous chemicals, they provide inorganic and organic nutrients, may form cryptic genes with DNA and dampen metabolic fluctuations. More recently they can increase adverse effects of hazardous chemicals and they can directly interfere with organisms. The book tries to relate effects to structural features.
Book Synopsis Dissertation Abstracts International by :
Download or read book Dissertation Abstracts International written by and published by . This book was released on 2004 with total page 788 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Direct and Indirect Photoreactions of Chromophoric Dissolved Organic Matter by : Jared Verrill Goldstone
Download or read book Direct and Indirect Photoreactions of Chromophoric Dissolved Organic Matter written by Jared Verrill Goldstone and published by . This book was released on 2002 with total page 278 pages. Available in PDF, EPUB and Kindle. Book excerpt: Photochemical transformations of chromophoric dissolved organic matter (CDOM) are one of the principal processes controlling its fate in coastal waters. The photochemical decomposition of CDOM leads to the formation of a variety of biologically available carbon substrates. Photomineralization of CDOM to dissolved inorganic carbon may constitute a significant flux in the global carbon cycle. Photoreactions ultimately lead to the destruction of the chromophores and hence to the loss of absorption and fluorescence (bleaching), thus acting as a sink for CDOM. Photodecomposition may proceed both via direct photochemical reactions, following absorption of photons by CDOM, or via indirect processes, involving DOM reactions with photochemically generated intermediates such as reactive oxygen species (ROS). The reactions of CDOM with two important ROS, superoxide (02- ) and hydroxyl radical (OH), have different consequences. Superoxide reactions with CDOM did not appear to degrade the CDOM. Instead, CDOM catalysed the dismutation of 02- to 02 and HOOH. This reactivity has the effect of limiting the steady-state concentration of 02- in most coastal waters. In contrast, reactions of CDOM with radiolytically produced OH formed CO2 and several low molecular weight carboxylic acids, as well as bleached both the absorption and fluorescence at slow rates. These reactions did not increase the bioavailability of this material to a microbial consortium. Both direct and indirect photochemical processes are expected to be accelerated by the presence of iron.
Book Synopsis Biogeochemistry of Marine Dissolved Organic Matter by : Dennis A. Hansell
Download or read book Biogeochemistry of Marine Dissolved Organic Matter written by Dennis A. Hansell and published by Academic Press. This book was released on 2014-10-02 with total page 712 pages. Available in PDF, EPUB and Kindle. Book excerpt: Marine dissolved organic matter (DOM) is a complex mixture of molecules found throughout the world's oceans. It plays a key role in the export, distribution, and sequestration of carbon in the oceanic water column, posited to be a source of atmospheric climate regulation. Biogeochemistry of Marine Dissolved Organic Matter, Second Edition, focuses on the chemical constituents of DOM and its biogeochemical, biological, and ecological significance in the global ocean, and provides a single, unique source for the references, information, and informed judgments of the community of marine biogeochemists. Presented by some of the world's leading scientists, this revised edition reports on the major advances in this area and includes new chapters covering the role of DOM in ancient ocean carbon cycles, the long term stability of marine DOM, the biophysical dynamics of DOM, fluvial DOM qualities and fate, and the Mediterranean Sea. Biogeochemistry of Marine Dissolved Organic Matter, Second Edition, is an extremely useful resource that helps people interested in the largest pool of active carbon on the planet (DOC) get a firm grounding on the general paradigms and many of the relevant references on this topic. Features up-to-date knowledge of DOM, including five new chapters The only published work to synthesize recent research on dissolved organic carbon in the Mediterranean Sea Includes chapters that address inputs from freshwater terrestrial DOM
Book Synopsis Dissolved Organic Matter Characterization and Impact on Mercury Binding in an Urbanizing Watershed by : Mykel Danielle Mendes
Download or read book Dissolved Organic Matter Characterization and Impact on Mercury Binding in an Urbanizing Watershed written by Mykel Danielle Mendes and published by . This book was released on 2011 with total page 96 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Photochemistry of Dissolved Organic Matter by : Stephen Andrew Timko
Download or read book Photochemistry of Dissolved Organic Matter written by Stephen Andrew Timko and published by . This book was released on 2014 with total page 145 pages. Available in PDF, EPUB and Kindle. Book excerpt: Constructed wetlands have the potential to provide low-energy treatment of pharmaceuticals and other micropollutants via photolysis. Natural dissolved organic matter (DOM) reacts with sunlight to produce reactive species such as singlet oxygen and excited triplet states of DOM that react quickly and efficiently with contaminants. To study the photo-chemistry of DOM, a unique solar-simulation system was developed, allowing for semi-continuous monitoring of absorbance and fluorescence spectra throughout the irradiation. This system was utilized to investigate the effect of solution pH on the fluorescence properties and degradation of DOM. For the first time, parallel factor (PARAFAC) analysis was utilized to deconvolute photo-labile, photo-stable, and pH- dependent fluorescent components during irradiation. Fluorescence is highly pH dependent, and as pH increases, the total amount of fluorescence loss, and the rate at which it is lost, increases significantly. This has important implications in treatment systems, as the photo-reactivity of DOM will change when pH gradients or fluctuations are observed. The photo-degradation of organic matter collected from a depth profile (0-4,500 m) the Sargasso Sea showed increased reactivity with increasing depth. Ultra-high resolution mass spectrometry (FT-MS) was used to characterize the samples, and correlation analyses between the fluorescence data and mass spectra revealed that high molecular weight, aromatic, and possibly polyphenolic compounds are contributing the most to the fluorescence properties that show the most reactivity in marine samples.Production of singlet oxygen, hydroxyl radical, and triplet excited states of DOM along two riverine transects in the Everglades were measured. The abundance of fluorescence PARAFAC components was compared to the reactive species production, and suggested that terrestrial organic matter may be more efficient producers of reactive species than microbial- or seagrass- derived organic matter.Finally, the relationship between optical properties of DOM samples collected around the world and their reactivity were investigated. Photo-irradiations and pH titrations were performed on all samples, and mass spectra collected via FT-MS. Humification indices, the biological index (BIX), and spectral slope from 275-295 nm were found to be most closely tied to changes in the mass spectra of the samples, and showed strong relationship to DOM source.
Book Synopsis Photochemical Reactivity of Dissolved Organic Matter in the Delaware Estuary by : Emily M White
Download or read book Photochemical Reactivity of Dissolved Organic Matter in the Delaware Estuary written by Emily M White and published by . This book was released on 2007 with total page 474 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Towards an Understanding of Dissolved Organic Matter Molecular Composition and Reactivity in the Environment by : Barbara Cottrell
Download or read book Towards an Understanding of Dissolved Organic Matter Molecular Composition and Reactivity in the Environment written by Barbara Cottrell and published by . This book was released on 2013 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
