SURFACE COMPLEXATION OF ACTINIDES WITH IRON OXIDES PDF Download
Are you looking for read ebook online? Search for your book and save it on your Kindle device, PC, phones or tablets. Download SURFACE COMPLEXATION OF ACTINIDES WITH IRON OXIDES PDF full book. Access full book title SURFACE COMPLEXATION OF ACTINIDES WITH IRON OXIDES by Y. Tsai. Download full books in PDF and EPUB format.
Author: Y. Tsai Publisher: ISBN: Category : Languages : en Pages :
Book Description
The surface complexation of actinides with iron oxides plays a key role in actinide transport and retardation in geosphere-biosphere systems. The development of accurate actinide transport models therefore requires a mechanistic understanding of surface complexation reactions (i.e. knowledge of chemical speciation at mineral/fluid interfaces). Iron oxides are particularly important actinide sorbents due to their pH dependent surface charges, relatively high surface areas and ubiquity in oxic and suboxic near-surface systems. In this paper we present results from field and laboratory investigations that elucidate the mechanisms involved in binding uranium and neptunium to iron oxide mineral substrates in near neutral groundwaters. The field study involved sampling and characterizing uranium-bearing groundwaters and solids from a saprolite aquifer overlying an unmined uranium deposit in the Virginia Piedmont. The groundwaters were analyzed by inductively coupled mass spectrometry and ion chromatography and the aquifer solids were analyzed by electron microprobe. The laboratory study involved a series of batch sorption tests in which U(VI) and Np(V) were reacted with goethite, hematite and magnetite in simulated groundwaters. The pH, ionic strength, aging time, and sorbent/sorbate ratios were varied in these experiments. The oxidation state and coordination environment of neptunium in solutions and sorbents from the batch tests were characterized by X-ray absorption spectroscopy (XAS) at the Advanced Photon Source, Argonne National Laboratory. Results from this work indicate that, in oxidizing near-surface aquifers, the dissolved concentration of uranium may be limited to less than 30 parts per billion due to uptake by iron oxide mineral coatings and the precipitation of sparingly soluble U(VI) phosphate minerals. Results from the batch adsorption tests showed that, in near neutral groundwaters, a significant fraction of the uranium and neptunium adsorbed as strongly bound surface complexes that were not removed (desorbed) when the sorbents were resuspended in dilute groundwater. The XAS results indicate that at pH 7.0-8.0 neptunium adsorbs to goethite as a neptunyl(V) complex and to magnetite as an inner-sphere Np(lV) complex with a Np-Fe distance of approximately 3.5 angstroms. These findings demonstrate that the presence of iron oxides in oxidizing near-surface aquifers may significantly retard actinide transport and that future reactive-transport models for actinides should therefore account for irreversible sorption processes.
Author: Y. Tsai Publisher: ISBN: Category : Languages : en Pages :
Book Description
The surface complexation of actinides with iron oxides plays a key role in actinide transport and retardation in geosphere-biosphere systems. The development of accurate actinide transport models therefore requires a mechanistic understanding of surface complexation reactions (i.e. knowledge of chemical speciation at mineral/fluid interfaces). Iron oxides are particularly important actinide sorbents due to their pH dependent surface charges, relatively high surface areas and ubiquity in oxic and suboxic near-surface systems. In this paper we present results from field and laboratory investigations that elucidate the mechanisms involved in binding uranium and neptunium to iron oxide mineral substrates in near neutral groundwaters. The field study involved sampling and characterizing uranium-bearing groundwaters and solids from a saprolite aquifer overlying an unmined uranium deposit in the Virginia Piedmont. The groundwaters were analyzed by inductively coupled mass spectrometry and ion chromatography and the aquifer solids were analyzed by electron microprobe. The laboratory study involved a series of batch sorption tests in which U(VI) and Np(V) were reacted with goethite, hematite and magnetite in simulated groundwaters. The pH, ionic strength, aging time, and sorbent/sorbate ratios were varied in these experiments. The oxidation state and coordination environment of neptunium in solutions and sorbents from the batch tests were characterized by X-ray absorption spectroscopy (XAS) at the Advanced Photon Source, Argonne National Laboratory. Results from this work indicate that, in oxidizing near-surface aquifers, the dissolved concentration of uranium may be limited to less than 30 parts per billion due to uptake by iron oxide mineral coatings and the precipitation of sparingly soluble U(VI) phosphate minerals. Results from the batch adsorption tests showed that, in near neutral groundwaters, a significant fraction of the uranium and neptunium adsorbed as strongly bound surface complexes that were not removed (desorbed) when the sorbents were resuspended in dilute groundwater. The XAS results indicate that at pH 7.0-8.0 neptunium adsorbs to goethite as a neptunyl(V) complex and to magnetite as an inner-sphere Np(lV) complex with a Np-Fe distance of approximately 3.5 angstroms. These findings demonstrate that the presence of iron oxides in oxidizing near-surface aquifers may significantly retard actinide transport and that future reactive-transport models for actinides should therefore account for irreversible sorption processes.
Author: John K. Gibson Publisher: John Wiley & Sons ISBN: 111911554X Category : Science Languages : en Pages : 670
Book Description
A review of contemporary actinide research that focuses on new advances in experiment and theory, and the interplay between these two realms Experimental and Theoretical Approaches to Actinide Chemistry offers a comprehensive review of the key aspects of actinide research. Written by noted experts in the field, the text includes information on new advances in experiment and theory and reveals the interplay between these two realms. The authors offer a multidisciplinary and multimodal approach to the nature of actinide chemistry, and explore the interplay between multiple experiments and theory, as well as between basic and applied actinide chemistry. The text covers the basic science used in contemporary studies of the actinide systems, from basic synthesis to state-of-the-art spectroscopic and computational techniques. The authors provide contemporary overviews of each topic area presented and describe the current and anticipated experimental approaches for the field, as well as the current and future computational chemistry and materials techniques. In addition, the authors explore the combination of experiment and theory. This important resource: Provides an essential resource the reviews the key aspects of contemporary actinide research Includes information on new advances in experiment and theory, and the interplay between the two Covers the basic science used in contemporary studies of the actinide systems, from basic synthesis to state-of-the-art spectroscopic and computational techniques Focuses on the interplay between multiple experiments and theory, as well as between basic and applied actinide chemistry Written for academics, students, professionals and researchers, this vital text contains a thorough review of the key aspects of actinide research and explores the most recent advances in experiment and theory.
Author: Johannes Lutzenkirchen Publisher: Elsevier ISBN: 0080467784 Category : Technology & Engineering Languages : en Pages : 653
Book Description
Surface Complexation Modelling deals with various aspects associate to the modelling of solutes adsorption from of solutes from aqueous solutions to minerals. The individual contributions cover fundamental aspects and applications. Applications cover case studies and present consistent surface complexation parameter sets. The model approaches range from simplistic to mechanistic. More fundamental contributions address underlying phenomena or stress the opportunities of modern computational methods. Several mineral systems are covered, including goethite, gibbsite, clay minerals etc.Surface Complexation Modelling presents the state-of-the-art of surface complexation modelling and suggests ideas for further model development. A number of chapters are authored by scientists working on nuclear waste storage, where the retention of radionuclides contributes to preventing radionuclide migration from the repository to the biosphere. Other contributions come from soil and environmental chemists with an interest in reactive transport of pollutants in soils or aquifers. - Covering a wide range of disciplines - Bringing together contributions from experts in the field - Providing a balance between the theoretical and applied aspects
Author: Iain May Publisher: Royal Society of Chemistry ISBN: 1847555365 Category : Science Languages : en Pages : 831
Book Description
Actinide elements and their chemistry have a significant number of applications. Bringing together contributions from the leading experts in the field, Recent Advances in Actinide Science covers six main topics: * Analysis, the environment and biotransformations * Coordination and organometallic chemistry * Heavy elements * Nuclear fuels, materials and waste forms * Separations and solution chemistry * Spectroscopy, magnetism and superconductivity Covering a wide range of research from pure academic studies to applied industrial science and technology, this book distils the knowledge and achievements gained in actinide science over the last four years. This high level book is aimed at researchers, both industrial and academic, and provides a comprehensive overview of the current status of actinide science.
Author: Heinrich D Holland Publisher: Academic Press ISBN: 0123813921 Category : Science Languages : en Pages : 681
Book Description
Readings from the Treatise on Geochemistry offers an interdisciplinary reference for scientists, researchers and upper undergraduate and graduate level geochemistry students that is more affordable than the full Treatise. For professionals, this volume will provide an overview of the field as a whole. For students, it will provide more in-depth introductory content than is found in broad-based geochemistry textbooks. Articles were selected from chapters across all volumes of the full Treatise, and include: The Origin and Earliest History of the Earth, Compositional Evolution of the Mantle, Evolution of Sedimentary Rocks, Soil Formation, Geochemistry of Groundwater, Geologic History of Seawater, Hydrothermal Processes, and Biogeochemistry of Primary Production in the Sea. Comprehensive, interdisciplinary and authoritative content selected by leading subject experts Robust illustrations, figures and tables Affordably priced sampling of content from the full Treatise on Geochemistry
Author: Damien Faivre Publisher: John Wiley & Sons ISBN: 3527691383 Category : Science Languages : en Pages : 632
Book Description
Compiling all the information available on the topic, this ready reference covers all important aspects of iron oxides. Following a preliminary overview chapter discussing iron oxide minerals along with their unique structures and properties, the text goes on to deal with the formation and transformation of iron oxides, covering geological, synthetic, and biological formation, as well as various physicochemical aspects. Subsequent chapters are devoted to characterization techniques, with a special focus on X-ray-based methods, magnetic measurements, and electron microscopy alongside such traditional methods as IR/Raman and Mossbauer spectroscopy. The final section mainly concerns exciting new applications of magnetic iron oxides, for example in medicine as microswimmers or as water filtration systems, while more conventional uses as pigments or in biology for magnetoreception illustrate the full potential. A must-read for anyone working in the field.
Author: Arthur T. Hubbard Publisher: CRC Press ISBN: 9780824707576 Category : Science Languages : en Pages : 1580
Book Description
This comprehensive reference collects fundamental theories and recent research from a wide range of fields including biology, biochemistry, physics, applied mathematics, and computer, materials, surface, and colloid science-providing key references, tools, and analytical techniques for practical applications in industrial, agricultural, and forensic processes, as well as in the production of natural and synthetic compounds such as foods, minerals, paints, proteins, pharmaceuticals, polymers, and soaps.
Author: L.R. Morss Publisher: Springer Science & Business Media ISBN: 9400702116 Category : Science Languages : en Pages : 4511
Book Description
The fourth edition of "The Chemistry of the Actinide and Transactinide Elements" comprises all chapters in volumes 1 through 5 of the third edition (published in 2006) plus a new volume 6. To remain consistent with the plan of the first edition, “ ... to provide a comprehensive and uniform treatment of the chemistry of the actinide [and transactinide] elements for both the nuclear technologist and the inorganic and physical chemist,” and to be consistent with the maturity of the field, the fourth edition is organized in three parts. The first group of chapters follows the format of the first and second editions with chapters on individual elements or groups of elements that describe and interpret their chemical properties. A chapter on the chemical properties of the transactinide elements follows. The second group, chapters 15-26, summarizes and correlates physical and chemical properties that are in general unique to the actinide elements, because most of these elements contain partially-filled shells of 5f electrons whether present as isolated atoms or ions, as metals, as compounds, or as ions in solution. The third group, chapters 27-39, focuses on specialized topics that encompass contemporary fields related to actinides in the environment, in the human body, and in storage or wastes. Two appendices at the end of volume 5 tabulate important nuclear properties of all actinide and transactinide isotopes. Volume 6 (Chapters 32 through 39) consists of new chapters that focus on actinide species in the environment, actinide waste forms, nuclear fuels, analytical chemistry of plutonium, actinide chalcogenide and hydrothermal synthesis of actinide compounds. The subject and author indices and list of contributors encompass all six volumes.
Author: Y. Tsai
Author: Y. Tsai
Author: Alan Blasenstein
Author: John K. Gibson
Author: Johannes Lutzenkirchen
Author: Iain May
Author: Heinrich D Holland
Author: Damien Faivre
Author: Arthur T. Hubbard
Author: 
Author: L.R. Morss