Download or read book Dissolution Kinetics of Ni II Surface Precipitates on Kaolinite written by and published by . This book was released on 2000 with total page 18 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Kinetics and Mechanisms of the Formation and Dissolution of Nickel II Surface Precipitates on Clay Minerals and Metal Oxides Using Macroscopic Spectroscopic Microscopic and Thermogravimetric Techniques written by Kirk Gerald Scheckel and published by . This book was released on 2000 with total page 418 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Environmental Soil Chemistry written by Donald L. Sparks and published by Elsevier. This book was released on 2003-01-04 with total page 367 pages. Available in PDF, EPUB and Kindle. Book excerpt: Environmental Soil Chemistry illustrates fundamental principles of soil chemistry with respect to environmental reactions between soils and other natural materials and heavy metals, pesticides, industrial contaminants, acid rain, and salts. Timely and comprehensive discussions of applications to real-world environmental concerns are a central focus of this established text. - Provides students with both sound contemporary training in the basics of soil chemistry and applications to real-world environmental concerns - Timely and comprehensive discussion of important concepts including: sorption/desorption, oxidation-reduction of metals and organics, and effects of acidic deposition and salinity on contaminant reacions - Boxed sections focus on sample problems and explanations of key terms and parameters - Extensive tables on elemental composition of soils, rocks and sediments, pesticide classes, inorganic minerals, and methods of decontaminating soils - Clearly written for all students and professionals in environmental science and environmental engineering as well as soil science
Download or read book Kaolinite Dissolution and Precipitation Kinetics at 22oC and PH 4 written by and published by . This book was released on 2008 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Dissolution and precipitation rates of low defect Georgia kaolinite (KGa-1b) as a function of Gibbs free energy of reaction (or reaction affinity) were measured at 22 C and pH 4 in continuously stirred flowthrough reactors. Steady state dissolution experiments showed slightly incongruent dissolution, with a Si/Al ratio of about 1.12 that is attributed to the re-adsorption of Al on to the kaolinite surface. No inhibition of the kaolinite dissolution rate was apparent when dissolved aluminum was varied from 0 and 60 [mu]M. The relationship between dissolution rates and the reaction affinity can be described well by a Transition State Theory (TST) rate formulation with a Temkin coefficient of 2 R{sub diss} (mol/m2s) = 1.15 x 10−13 [1-exp( -[Delta]G/2RT)]. Stopping of flow in a close to equilibrium dissolution experiment yielded a solubility constant for kaolinite at 22 C of 10{sup 7.57}. Experiments on the precipitation kinetics of kaolinite showed a more complex behavior. One conducted using kaolinite seed that had previously undergone extensive dissolution under far from equilibrium conditions for 5 months showed a quasi-steady state precipitation rate for 105 hours that was compatible with the TST expression above. After this initial period, however, precipitation rates decreased by an order of magnitude, and like other precipitation experiments conducted at higher supersaturation and without kaolinite seed subjected to extensive prior dissolution, could not be described with the TST law. The initial quasi-steady state rate is interpreted as growth on activated sites created by the dissolution process, but this reversible growth mechanism could not be maintained once these sites were filled. Long-term precipitation rates showed a linear dependence on solution saturation state that is generally consistent with a two dimensional nucleation growth mechanism following the equation R{sub ppt}(mol/m2s) = 3.38 x 10−14 exp[- 181776/T2 1n[Omega]]. Further analysis using Synchrotron Scanning Transmission X-ray Microscopy (STXM) in Total Electron Yield (TEY) mode of the material from the precipitation experiments showed spectra for newly precipitated material compatible with kaolinite. An idealized set of reactive transport simulations of the chemical weathering of albite to kaolinite using rate laws from HELLMANN and TISSERAND (2006) and this study respectively indicate that while pore waters are likely to be close to equilibrium with respect to kaolinite at pH 4, significant kaolinite supersaturation may occur at higher pH if its precipitation rate is pH dependent.
Download or read book Kaolinite Dissolution and Precipitation Kinetics at 22oC and PH4 written by and published by . This book was released on 2007 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Dissolution and precipitation rates of low defect Georgia kaolinite (KGa-1b) as a function of Gibbs free energy of reaction (or reaction affinity) were measured at 22 C and pH 4 in continuously stirred flow through reactors. Steady state dissolution experiments showed slightly incongruent dissolution, with a Si/Al ratio of about 1.12 that is attributed to the re-adsorption of Al on to the kaolinite surface. No inhibition of the kaolinite dissolution rate was apparent when dissolved aluminum was varied from 0 and 60 [mu]M. The relationship between dissolution rates and the reaction affinity can be described well by a Transition State Theory (TST) rate formulation with a Temkin coefficient of 2 R{sub diss} (mol/m2s) = 1.15 x 10−13 [1-exp( -[Delta]G/2RT)]. Stopping of flow in a close to equilibrium dissolution experiment yielded at solubility constant for kaolinite at 22 C of 10{sup 7.57}. Experiments on the precipitation kinetics of kaolinite showed a more complex behavior. One conducted using kaolinite seed that had previously undergone extensive dissolution under far from equilibrium conditions for 5 months showed a quasi-steady state precipitation rate for 105 hours that was compatible with the TST expression above. After this initial period, however, precipitation rates decreased by an order of magnitude, and like other precipitation experiments conducted at higher supersaturation and without kaolinite seed subjected to extensive prior dissolution, could not be described with the TST law. The initial quasi-steady state rate is interpreted as growth on activated sites created by the dissolution process, but this reversible growth mechanism could not be maintained once these sites were filled. Long-term precipitation rates showed a linear dependence on solution saturation state that is generally consistent with a two dimensional nucleation growth mechanism following the equation R{sub ppt}(mol/m2s) = 3.38 x 10−14 exp[181776/T21n[Omega]]. Further analysis using Synchrotron Scanning Transmission X-ray Microscopy (STXM) in Total Electron Yield (TEY) mode of the material from the precipitation experiments showed spectra for newly precipitated material compatible with kaolinite.
Download or read book Handbook of Clay Science written by Faïza Bergaya and published by Elsevier. This book was released on 2011-09-14 with total page 1248 pages. Available in PDF, EPUB and Kindle. Book excerpt: The first general texts on clay mineralogy and the practical applications of clay, written by R.E. Grim, were published some 40-50 years ago. Since then, a vast literature has accumulated but this information is scattered and not always accessible. The Handbook of Clay Science aims at assembling the scattered literature on the varied and diverse aspects that make up the discipline of clay science. The topics covered range from the fundamental structures (including textures) and properties of clays and clay minerals, through their environmental, health and industrial applications, to their analysis and characterization by modern instrumental techniques. Also included are the clay-microbe interaction, layered double hydroxides, zeolites, cement hydrates, genesis of clay minerals as well as the history and teaching of clay science. No modern book in the English language is available that is as comprehensive and wide-ranging in coverage as the Handbook of Clay Science.In providing a critical and up-to-date assessment of the accumulated information, this will serve as the first point of entry into the literature for both newcomers and graduate students, while for research scientists, university teachers, industrial chemists, and environmental engineers the book will become a standard reference text.* Presents contributions from 66 authors from 18 different countries who have come together to produce the most comprehensive modern handbook on clay science* Provides up-to-date concepts, properties, and reactivity of clays and clay minerals in a one-stop source of information* Covers classical and new environmental, industrial, and health applications of clays, as well as the instrumental techniques for clay mineral analysis* Combines geology, mineralogy, crystallography with physics, geotechnology, and soil mechanics together with inorganic, organic, physical, and colloid chemistry for a truly multidisciplinary approach
Download or read book Advances in Agronomy written by and published by Elsevier. This book was released on 2001-09-28 with total page 267 pages. Available in PDF, EPUB and Kindle. Book excerpt: Volume 74 contains six excellent cutting-edge reviews detailing advances in the plant and environmental soil sciences. Chapter 1 is an extensive review on soil quality. Chapter 2 covers recent advances in understanding the formation of metal hydroxide precipitates on soil surfaces and their implications on metal sequestration and soil remediation. Chapter 3 is a timely review on effects of organic acid exudation from roots on phosphorus uptake and aluminum tolerance of plants in acid soils. Chapter 4 discusses bamboo production and management, including manipulation of growth and development and environmental aspects of bamboo production. Chapter 5 addresses a significant worldwide issue - management of soils for food security and environmental quality. Chapter 6 is a comprehensive review on the management of wheat, barley, and oat root systems.
Download or read book Annual Meetings Abstracts written by American Society of Agronomy and published by . This book was released on 1999 with total page 464 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Handbook of Soil Sciences Two Volume Set written by Pan Ming Huang and published by CRC Press. This book was released on 2018-10-03 with total page 2249 pages. Available in PDF, EPUB and Kindle. Book excerpt: An evolving, living organic/inorganic covering, soil is in dynamic equilibrium with the atmosphere above, the biosphere within, and the geology below. It acts as an anchor for roots, a purveyor of water and nutrients, a residence for a vast community of microorganisms and animals, a sanitizer of the environment, and a source of raw materials for co
Download or read book Surface Characteristics and Dissolution Kinetics of Two Standard Kaolinites written by Qunhui Zhou and published by . This book was released on 1996 with total page 426 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Nickel in Soils and Plants written by Christos Tsadilas and published by CRC Press. This book was released on 2018-09-03 with total page 414 pages. Available in PDF, EPUB and Kindle. Book excerpt: Soils with high Ni contents occur in several parts of the world, especially in areas with ultramafic rocks which cause serious environmental impacts. This book aims to extend the knowledge on the risks and problems caused by elevated Ni contents and to cover the existing gaps on issues related to various aspects and consequences of high Ni contents in soils and plants. Nickel in Soils and Plants brings together discussions on Ni as a trace element and as a micronutrient essential for plant growth and its role in plant physiology. It analyzes the biogeochemistry of Ni at the soil plant interface, and explains its behavior in the rhizosphere resulting in Ni deficiency or toxicity, or Ni tolerance of various Ni hyperaccumulators. Included are Ni resources and sources, the origin of soil Ni, its geochemical forms in soils and their availability to plants, a special reference on soils enriched with geogenic Ni, such as serpentine soils, and the special characteristics of those ecosystems. Recent advancements in methods of Ni speciation, including the macroscale and X- ray absorption spectroscopy studies as well as serious views on Ni kinetics, are also covered. Written by a team of internationally recognized researchers and expert contributors, this comprehensive work addresses the practical aspects of managing Ni in soils and plants for agricultural production, and managing soils with high Ni levels by using organic and inorganic amendments. The text also addresses practical measures related to Ni toxicity in plants, the removal and recovery of Ni from high Ni wastes, and offers environmentally friendly innovative processes for mining Ni from soils containing high Ni levels.
Download or read book Fate and Transport of Heavy Metals in the Vadose Zone written by I.K. Iskandar and published by CRC Press. This book was released on 1999-04-23 with total page 350 pages. Available in PDF, EPUB and Kindle. Book excerpt: The chapters of this book were originally presented at the Fourth International Conference on the Biogeochemistry of Trace Elements, in June 1997 at Berkeley, California. The results of that symposium are now available to assist both specialists and those concerned with broader environmental issues. The first four chapters of Fate and Transport of Heavy Metals in the Vadose Zone are devoted to sorption-desorption processes. Subjects include the kinetics of trace metal sorption-desorption, adsorption of nickel and their isotherms, cadmium reactions, and retention mechanisms of both linear and nonlinear types. The next three sections describe complexation and speciation processes. The authors consider the effect of humic and fulvic acids, the binding of copper with organic matter, and the rate of dissolved selenium. Chapters eight through eleven scrutinize the bioavailability and retention of heavy metals and their mobility in the vadose zone. Twelve details plant-available concentration levels for heavy metals in the vadose zone. The last section relates case studies that are relevant to environmental affairs. Features
Download or read book Chemical Weathering Rates of Silicate Minerals written by Arthur F. White and published by Walter de Gruyter GmbH & Co KG. This book was released on 2018-12-17 with total page 600 pages. Available in PDF, EPUB and Kindle. Book excerpt: Volume 31 of Reviews in Mineralogy reviews current thinking on the fundamental processes that control chemical weathering of silicates, including the physical chemistry of reactions at mineral surfaces, the role of experimental design in isolating and quantifying these reactions, and the complex roles that water chemistry, hydrology, biology, and climate play in weathering of natural systems. The chapters in this volume are arranged to parallel this order of development from theoretical considerations to experimental studies to characterization of natural systems. Secondly, the book is meant to serve as a reference from which researchers can readily retrieve quantitative weathering rate data for specific minerals under detailed experimental controls or for natural weathering conditions. Toward this objective, the authors were encouraged to tabulate available weathering rate data for their specific topics. Finally this volume serves as a forum in which suggestions and speculations concerning the direction of future weathering research are discussed.
Download or read book Frontiers in Geochemistry written by Konrad Bates Krauskopf and published by Geological Society of America. This book was released on 2002 with total page 280 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Trace Elements in Soils written by Peter Hooda and published by John Wiley & Sons. This book was released on 2010-04-13 with total page 616 pages. Available in PDF, EPUB and Kindle. Book excerpt: Trace elements occur naturally in soils and some are essential nutrients for plant growth as well as human and animal health. However, at elevated levels, all trace elements become potentially toxic. Anthropogenic input of trace elements into the natural environment therefore poses a range of ecological and health problems. As a result of their persistence and potential toxicity, trace elements continue to receive widespread scientific and legislative attention. Trace Elements in Soils reviews the latest research in the field, providing a comprehensive overview of the chemistry, analysis, fate and regulation of trace elements in soils, as well as remediation strategies for contaminated soil. The book is divided into four sections: • Basic principles, processes, sampling and analytical aspects: presents an overview including general soil chemistry, soil sampling, analysis, fractionation and speciation. • Long-term issues, impacts and predictive modelling: reviews major sources of metal inputs, the impact on soil ecology, trace element deficient soils and chemical speciation modelling. • Bioavailability, risk assessment and remediation: discusses bioavailability, regulatory limits and cleanup technology for contaminated soils including phytoremediation and trace element immobilization. • Characteristics and behaviour of individual elements Written as an authoritative guide for scientists working in soil science, geochemistry, environmental science and analytical chemistry, the book is also a valuable resource for professionals involved in land management, environmental planning, protection and regulation.
Download or read book The Crystal Chemistry Dissolution Kinetics and Dehydroxylation of Oxide type Lateritic Ni Ore written by Matthew Landers and published by . This book was released on 2010 with total page 153 pages. Available in PDF, EPUB and Kindle. Book excerpt: The recent strong demand for Ni for steel production has significantly depleted the easily extractable Ni sulphide deposits, causing the mining industry to look towards the more abundant albeit complex, low-grade lateritic Ni deposits. There have been major difficulties in the extraction of Ni from lateritic Ni ores reflecting, inter alia, the limited knowledge of the location and distribution of Ni within minerals (particularly iron-oxides) in lateritic ores, as well as the limited understanding of the acid leaching kinetics of these minerals. A new method for improving the extraction of Ni from oxide-type (limonitic) lateritic Ni ores by means of shock heating has been investigated in this thesis utilising a combination of bulk and macroscopic techniques. Five oxide-type lateritic Ni ores from Indonesia (Weda Bay), Western Australia (Kalgoorlie and Ravensthorpe) and New Caledonia (Goro and Koiambo), composed mostly of acicular, nano-sized goethite crystals with minor amounts of quartz, talc, willemseite, maghemite, magnetite, asbolane, kaolinite, Mn oxides and various spinels. These minerals were identified using synchrotron X-ray diffraction (SXRD) and electron energy loss spectroscopy (EELS). The nickeliferous goethites were subjected to shock heating for 30 minutes at temperatures in the range 220-800°C. Goethite partially dehydroxylated to OH-hematite at 300-400°C and had completely altered to well ordered hematite at 800°C. OH-hematite has broad XRD reflections, structural water, high specific surface area, structural disorder and small crystal size. The high surface area (1.5-2.6 fold increase from that of goethite) is due to the formation of slit-shaped micropores (300°C), which further develop into elliptically-shaped micropores (400°C), and is partly responsible for a 9-34 fold increase in the dissolution rate constant k for the Kabai equation, measured from the dissolution of Fe in 2M H2SO4. The remaining 5-10 fold increase in the dissolution rate constant k is presumably due to the higher density of structural defects in OH-hematite. The presence of structural Al and Cr in goethite was shown to reduce dissolution rate possibly through the greater Me-OH, O bond strength relative to Fe, Ni-OH, O. Rapid high temperature dehydroxylation (800°C) of goethite resulted in the formation of well ordered hematite with no structural water, low surface area and with high structural order. The low surface area is due to the removal of most micropores and the development of extensive ordered hematite domains by surface and volume diffusion.
Download or read book Handbook of Soil Science written by Malcolm E. Sumner and published by CRC Press. This book was released on 1999-08-31 with total page 2240 pages. Available in PDF, EPUB and Kindle. Book excerpt: The Handbook of Soil Science provides a resource rich in data that gives professional soil scientists, agronomists, engineers, ecologists, biologists, naturalists, and their students a handy reference about the discipline of soil science. This handbook serves professionals seeking specific, factual reference information. Each subsection includes a description of concepts and theories; definitions; approaches; methodologies and procedures; tabular data; figures; and extensive references.
