Download or read book A Pore Scale Evaluation of the Kinetics of Mineral Dissolution and Precipitation Reactions EMSI written by Carl I. Steefel and published by . This book was released on 2006 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: The chief goals for CEKA are to (1) collect and synthesize molecular-level kinetic data into a coherent framework that can be used to predict time evolution of environmental processes over a range of temporal and spatial scales; (2) train a cohort of talented and diverse students to work on kinetic problems at multiple scales; (3) develop and promote the use of new experimental techniques in environmental kinetics; (4) develop and promote the use of new modeling tools to conceptualize reaction kinetics in environmental systems; and (5) communicate our understanding of issues related to environmental kinetics and issues of scale to the broader scientific community and to the public.

Download or read book Mineral Dissolution Kinetics at the Pore Scale written by and published by . This book was released on 2007 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Mineral dissolution rates in the field have been reported to be orders of magnitude slower than those measured in the laboratory, an unresolved discrepancy that severely limits our ability to develop scientifically defensible predictive or even interpretive models for many geochemical processes in the earth and environmental sciences. One suggestion links this discrepancy to the role of physical and chemical heterogeneities typically found in subsurface soils and aquifers in producing scale-dependent rates where concentration gradients develop. In this paper, we examine the possibility that scale-dependent mineral dissolution rates can develop even at the single pore and fracture scale, the smallest and most fundamental building block of porous media. To do so, we develop two models to analyze mineral dissolution kinetics at the single pore scale: (1) a Poiseuille Flow model that applies laboratory-measured dissolution kinetics at the pore or fracture wall and couples this to a rigorous treatment of both advective and diffusive transport, and (2) a Well-Mixed Reactor model that assumes complete mixing within the pore, while maintaining the same reactive surface area, average flow rate, and geometry as the Poiseuille Flow model. For a fracture, a 1D Plug Flow Reactor model is considered in addition to quantify the effects of longitudinal versus transverse mixing. The comparison of averaged dissolution rates under various conditions of flow, pore size, and fracture length from the three models is used as a means to quantify the extent to which concentration gradients at the single pore and fracture scale can develop and render rates scale-dependent. Three important minerals that dissolve at widely different rates, calcite, plagioclase, and iron hydroxide, are considered. The modeling indicates that rate discrepancies arise primarily where concentration gradients develop due to comparable rates of reaction and advective transport, and incomplete mixing via molecular diffusion. The magnitude of the reaction rate is important, since it is found that scaling effects (and thus rate discrepancies) are negligible at the single pore and fracture scale for plagioclase and iron hydroxide because of the slow rate at which they dissolve. In the case of calcite, where dissolution rates are rapid, scaling effects can develop at high flow rates from 0.1 cm/s to 1000 cm/s and for fracture lengths less than 1 cm. At more normal flow rates, however, mixing via molecular diffusion is effective in homogenizing the concentration field, thus eliminating any discrepancies between the Poiseuille Flow and the Well-Mixed Reactor model. This suggests that a scale dependence to mineral dissolution rates is unlikely at the single pore or fracture scale under normal geological/hydrologic conditions, implying that the discrepancy between laboratory and field rates must be attributed to other factors.

Download or read book Pore scale Analysis of Mixing controlled Calcium Carbonate Precipitation and Dissolution Kinetics in Microfluidic Experiments written by and published by . This book was released on 2013 with total page 18 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book A Novel Approach to Experimental Studies of Mineral Dissolution Kinetics written by and published by . This book was released on 2008 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Currently, DOE is conducting pilot CO2 injection tests to evaluate the concept of geological sequestration. The injected CO2 is expected to react with the host rocks and these reactions can potentially alter the porosity, permeability, and mechanical properties of the host or cap rocks. Reactions can also result in precipitation of carbonate-containing minerals that favorably and permanently trap CO2 underground. Many numerical models have been used to predict these reactions for the carbon sequestration program. However, a firm experimental basis for predicting silicate reaction kinetics in CO2 injected geological formations is urgently needed to assure the reliability of the geochemical models used for the assessments of carbon sequestration strategies. The funded experimental and theoretical study attempts to resolve this outstanding scientific issue by novel experimental design and theoretical interpretation of silicate dissolution rates at conditions pertinent to geological carbon sequestration. In this four year research grant (three years plus a one year no cost extension), seven (7) laboratory experiments of CO2-rock-water interactions were carried out. An experimental design allowed the collection of water samples during experiments in situ and thus prevented back reactions. Analysis of the in situ samples delineated the temporal evolution of aqueous chemistry because of CO2-rock-water interactions. The solid products of the experiments were retrieved at the end of the experimental run, and analyzed with a suite of advanced analytical and electron microscopic techniques (i.e., atomic resolution transmission electron microscopy (TEM), scanning electron microscopy (SEM), electron microprobe, X-ray diffraction, X-ray photoelectron spectroscopy (XPS)). As a result, the research project probably has produced one of the best data sets for CO2-rock-water interactions in terms of both aqueous solution chemistry and solid characterization. Three experiments were performed using the Navajo sandstone. Navajo sandstone is geologically equivalent to the Nugget sandstone, which is a target formation for a regional partnership injection project. Our experiments provided the experimental data on the potential CO2-rock-water interactions that are likely to occur in the aquifer. Geochemical modeling was performed to interpret the experimental results. Our single mineral (feldspar) experiments addressed a basic research need. i.e., the coupled nature of dissolution and precipitation reactions, which has universal implication to the reaction kinetics as it applied to CO2 sequestration. Our whole rock experiments (Navajo sandstone) addressed the applied research component, e.g., reacting Navajo sandstone with brine and CO2 has direct relevance on the activities of a number of regional partnerships. The following are the major findings from this project: (1) The project generated a large amount of experimental data that is central to evaluating CO2-water-rock interactions and providing ground truth to predictive models, which have been used and will inevitably be increasingly more used in carbon sequestration. (2) Results from the feldspar experiments demonstrated stronger coupling between dissolution and precipitation reactions. We show that the partial equilibrium assumption did not hold in the feldspar hydrolysis experiments (Zhu and Lu, submitted, Appendix A-2). The precipitation of clay minerals influenced dissolution of primary silicate in a much stronger way as previously envisioned. Therefore, our experimental data indicated a much more complex chemical kinetics as it has been applied to carbon sequestration program in terms of preliminary predictive models of CO2-rock-water interactions. Adopting this complexity (strong coupling) may influence estimates of mineral trapping and porosity/permeability for geological carbon sequestration. In general, our knowledge of the coupling of different reactions is poor, and we must consider the uncertainties resulting from our poor knowledge on this regard. (3) Our experimental results concur with previous findings that the role of dissolved CO2 is mostly to acidify the brine, but not change the mechanisms of reactions. This conclusion is based on careful paired experiments with and without CO2. (4) We observed strong chemical reactions between CO2 acidified brine with the Navajo sandstone. The laboratory experiments were conducted at a higher temperature (200 C) than that in the field ((almost equal to)90 C) in order to induce measurable chemical changes in the laboratory. However, field conditions are more acidic and reaction time is much longer (1000 years versus 10-80 days in the laboratory). Therefore, the conclusions on extensive reactions are relevant. We observed extensive dissolution of feldspars, and precipitation of clay minerals.

Download or read book A Novel Approach to Experimental Studies of Mineral Dissolution Kinetics written by Chen Zhu and published by . This book was released on 2005 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Currently, DOE is conducting pilot CO{sub 2} injection tests to evaluate the concept of geological sequestration. One strategy that potentially enhances CO{sub 2} solubility and reduces the risk of CO{sub 2} leak back to the surface is dissolution of indigenous minerals in the geological formation and precipitation of secondary carbonate phases, which increases the brine pH and immobilizes CO{sub 2}. Clearly, the rates at which these dissolution and precipitation reactions occur directly determine the efficiency of this strategy. However, one of the fundamental problems in modern geochemistry is the persistent two to five orders of magnitude discrepancy between laboratory-measured and field derived feldspar dissolution rates. To date, there is no real guidance as to how to predict silicate reaction rates for use in quantitative models. Current models for assessment of geological carbon sequestration have generally opted to use laboratory rates, in spite of the dearth of such data for compositionally complex systems, and the persistent disconnect between lab and field applications. Therefore, a firm scientific basis for predicting silicate reaction kinetics in CO{sub 2} injected geological formations is urgently needed to assure the reliability of the geochemical models used for the assessments of carbon sequestration strategies. The funded experimental and theoretical study attempts to resolve this outstanding scientific issue by novel experimental design and theoretical interpretation to measure silicate dissolution rates and iron carbonate precipitation rates at conditions pertinent to geological carbon sequestration. In the first year of the project, we have successfully developed a sample preparation method and completed three batch feldspar dissolution experiments at 200 C and 300 bars. The changes of solution chemistry as dissolution experiments progressed were monitored with on-line sampling of the aqueous phase at the constant temperature and pressure. These data allow calculating overall apparent feldspar dissolution rates and secondary mineral precipitation rates as a function of saturation states. State-of-the-art atomic resolution transmission electron microscopy (TEM), scanning electron microscopy, and electron microprobe was used to characterize the reactants (feldspars before experiments). We experimented with different sample preparation methods for TEM study, and found excellent images and chemical resolution with reactants, which shows promise of the technology and establishes the baseline for comparison with products (feldspars after the experiments). Preliminary electron microscopic characterization shows that the reacted feldspars have etch pits and are covered with secondary sheet silicate phases. Reaction-path geochemical modeling is used to interpret the experimental results. We have established the software and database, and are making great progress. Also during the first year, our education goal of graduate student training has been achieved. A Ph. D. student at Indiana University is progressing well in the degree program and has taken geochemical modeling, SEM, and TEM courses, which will facilitate research in the second and third year. A Ph. D. student at University of Minnesota is progressing well in conducting the experiments, and is near graduation. With the success of training of graduate students and excellent experimental data in the first year, we anticipate a more fruitful year in the second year.

Download or read book Mineral water Interfacial Reactions written by Donald L. Sparks and published by . This book was released on 1998 with total page 460 pages. Available in PDF, EPUB and Kindle. Book excerpt: Clearly explains how to more effectively decipher and predict contaminant fate in the environment by combining kinetic methods and molecular-scale spectroscopic and microscopic techniques to analyze mineral/water interfacial reactions in situ. The book begins with a broad overview, then continues with three sections written by internationally known expert. The first deals specifically with spectroscopic/microscopic techniques that can be used in combination with macroscopic approaches to glean mechanistic information on mineral/water reactions and processes. The second section emphasizes computer models that are used to elucidate surface mediated reaction mechanisms. The remainder of the volume is organized around reaction type, including sorption/desorption of inorganic species, sorption/desorption of organic species, precipitation/dissolution processes, heterogeneous electron transfer reactions, photochemically driven reactions, and microbially mediated reactions. Mineral-Water Interfacial Reactions will be a valuable resource for environmental scientists, geochemists, soil chemists, microbiologists, and marine engineers who need to be familiar with the most current and effective methods for testing and controlling the mobility, speciation, and bioavailability of contaminants in the environment.

Download or read book Crystal Dissolution and Precipitation in Porous Media written by Cornelis Johannes Duijn and published by . This book was released on 2003 with total page 44 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Environmental Chemistry of Arsenic written by William T. Frankenberger, Jr and published by CRC Press. This book was released on 2001-12-04 with total page 420 pages. Available in PDF, EPUB and Kindle. Book excerpt: With contributions from world-renowned experts in the field, this book explores developments in the transport kinetics, seasonal cycling, accumulation, geochemistry, transformation, and toxicology of arsenic. It details advances in the prevention and control of arsenic and arsenic compounds in the air, soil, and water and offers analytical methods for the detection and study of arsenic in the environment and human body. Providing bioremediation techniques for effective treatment of contaminated water supplies, the book discusses factors that influence the removal of arsenic from water as well as diurnal and seasonal variations in the arsenic concentration of surface water supplies.

Download or read book Evaluation of the Microbiology Standards for Drinking Water written by Charles W. Hendricks and published by . This book was released on 1979 with total page 252 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Synthesis Properties and Applications of Oxide Nanomaterials written by José A. Rodriguez and published by John Wiley & Sons. This book was released on 2007-03-09 with total page 38 pages. Available in PDF, EPUB and Kindle. Book excerpt: Current oxide nanomaterials knowledge to draw from and build on Synthesis, Properties, and Applications of Oxide Nanomaterials summarizes the existing knowledge in oxide-based materials research. It gives researchers one comprehensive resource that consolidates general theoretical knowledge alongside practical applications. Organized by topic for easy access, this reference: * Covers the fundamental science, synthesis, characterization, physicochemical properties, and applications of oxide nanomaterials * Explains the fundamental aspects (quantum-mechanical and thermodynamic) that determine the behavior and growth mode of nanostructured oxides * Examines synthetic procedures using top-down and bottom-up fabrication technologies involving liquid-solid or gas-solid transformations * Discusses the sophisticated experimental techniques and state-of-the-art theory used to characterize the structural and electronic properties of nanostructured oxides * Describes applications such as sorbents, sensors, ceramic materials, electrochemical and photochemical devices, and catalysts for reducing environmental pollution, transforming hydrocarbons, and producing hydrogen With its combination of theory and real-world applications plus extensive bibliographic references, Synthesis, Properties, and Applications of Oxide Nanomaterials consolidates a wealth of current, complex information in one volume for practicing chemists, physicists, and materials scientists, and for engineers and researchers in government, industry, and academia. It's also an outstanding reference for graduate students in chemistry, chemical engineering, physics, and materials science.

Download or read book Synchrotron Based Techniques in Soils and Sediments written by Balwant Singh and published by Elsevier. This book was released on 2010-02-18 with total page 509 pages. Available in PDF, EPUB and Kindle. Book excerpt: Over the past 20 years, synchrotron-based research applications have provided important insight into the geochemical cycling of ions and the chemical and crystallographic properties of minerals in soils and sediments. Of particular significance is the understanding of local coordination environments with the use of X-ray absorption spectroscopy. The high flux and brightness of the X-ray beams have allowed researchers to work at environmentally relevant concentrations. The use of focusing mirrors and apertures which allow for mapping and trace particle surfaces, microbes, roots, channels and elements at the micron and at a nano-meter scale in 2 and 3D have also been a great enhancement to science. This book provides the most up-to-date information on synchrotron-based research applications in the field of soil, sediment and earth sciences. Invited authors provide chapters on a wide range of research topics including multiphase flow and transport processes (physical aspects), rhizosphere and microbial life (biological aspects), and dynamics of C, N, S, P and heavy metals and metalloids (chemical aspects). In addition, perspectives on the impact of synchrotron based applications, particularly X-ray absorption spectroscopy, and the role of synchrotron applications in remediation, regulatory, and decision making processes are considered. - Up-to-date, with the latest research results and techniques in synchrotron-based techniques - Information on specific techniques, elements and minerals, regulatory and remediation decision making, contaminants and the impact of X-ray absorption spectroscopy on soil science - Internationally recognized leaders in their fields of expertise from Europe, North America, Asia and Australia

Download or read book Mountain Biking written by Deborah J. Chavez and published by . This book was released on 1996 with total page 44 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Environmental and Pollution Science written by Mark L. Brusseau and published by Academic Press. This book was released on 2019-02-22 with total page 658 pages. Available in PDF, EPUB and Kindle. Book excerpt: Environmental and Pollution Science, Third Edition, continues its tradition on providing readers with the scientific basis to understand, manage, mitigate, and prevent pollution across the environment, be it air, land, or water. Pollution originates from a wide variety of sources, both natural and man-made, and occurs in a wide variety of forms including, biological, chemical, particulate or even energy, making a multivariate approach to assessment and mitigation essential for success. This third edition has been updated and revised to include topics that are critical to addressing pollution issues, from human-health impacts to environmental justice to developing sustainable solutions. Environmental and Pollution Science, Third Edition is designed to give readers the tools to be able to understand and implement multi-disciplinary approaches to help solve current and future environmental pollution problems. - Emphasizes conceptual understanding of environmental systems and can be used by students and professionals from a diversity of backgrounds focusing on the environment - Covers many aspects critical to assessing and managing environmental pollution including characterization, risk assessment, regulation, transport and fate, and remediation or restoration - New topics to this edition include Ecosystems and Ecosystem Services, Pollution in the Global System, Human Health Impacts, the interrelation between Soil and Human Health, Environmental Justice and Community Engagement, and Sustainability and Sustainable Solutions - Includes color photos and diagrams, chapter questions and problems, and highlighted key words

Download or read book Advanced Transmission Electron Microscopy written by Francis Leonard Deepak and published by Springer. This book was released on 2015-06-05 with total page 281 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book highlights the current understanding of materials in the context of new and continuously emerging techniques in the field of electron microscopy. The authors present applications of electron microscopic techniques in characterizing various well-known & new nanomaterials. The applications described include both inorganic nanomaterials as well as organic nanomaterials.

Download or read book Conservation for the Anthropocene Ocean written by Phillip S. Levin and published by Academic Press. This book was released on 2017-06-01 with total page 532 pages. Available in PDF, EPUB and Kindle. Book excerpt: Conservation for the Anthropocene Ocean: Interdisciplinary Science in Support of Nature and People emphasizes strategies to better connect the practice of marine conservation with the needs and priorities of a growing global human population. It conceptualizes nature and people as part of shared ecosystems, with interdisciplinary methodologies and science-based applications for coupled sustainability. A central challenge facing conservation is the development of practical means for addressing the interconnectedness of ecosystem health and human well-being, advancing the fundamental interdisciplinary science that underlies conservation practice, and implementing this science in decisions to manage, preserve, and restore ocean ecosystems. Though humans have intentionally and unintentionally reshaped their environments for thousands of years, the scale and scope of human influence upon the oceans in the Anthropocene is unprecedented. Ocean science has increased our knowledge of the threats and impacts to ecological integrity, yet the unique scale and scope of changes increases uncertainty about responses of dynamic socio-ecological systems. Thus, to understand and protect the biodiversity of the ocean and ameliorate the negative impacts of ocean change on people, it is critical to understand human beliefs, values, behaviors, and impacts. Conversely, on a human-dominated planet, it is impossible to understand and address human well-being and chart a course for sustainable use of the oceans without understanding the implications of environmental change for human societies that depend on marine ecosystems and resources. This work therefore presents a timely, needed, and interdisciplinary approach to the conservation of our oceans. Helps marine conservation scientists apply principles from oceanography, ecology, anthropology, economics, political science, and other natural and social sciences to manage and preserve marine biodiversity Facilitates understanding of how and why social and environmental processes are coupled in the quest to achieve healthy and sustainable oceans Uses a combination of expository material, practical approaches, and forward-looking theoretical discussions to enhance value for readers as they consider conservation research, management and planning

Download or read book Environmental Monitoring and Characterization written by Janick Artiola and published by Elsevier. This book was released on 2004-06-10 with total page 425 pages. Available in PDF, EPUB and Kindle. Book excerpt: Environmental Monitoring and Characterization is an integrated, hands-on resource for monitoring all aspects of the environment. Sample collection methods and relevant physical, chemical and biological processes necessary to characterize the environment are brought together in twenty chapters which cover: sample collection methods, monitoring terrestrial, aquatic and air environments, and relevant chemical, physical and biological processes and contaminants. This book will serve as an authoritative reference for advanced students and environmental professionals. - Examines the integration of physical, chemical, and biological processes - Emphasizes field methods and real-time data acquisition, made more accessible with case studies, problems, calculations, and questions - Includes four color illustrations throughout the text - Brings together the concepts of environmental monitoring and site characterization

Download or read book Biogeochemistry of Environmentally Important Trace Elements written by Yong Cai and published by . This book was released on 2003 with total page 456 pages. Available in PDF, EPUB and Kindle. Book excerpt: Biogeochemistry of Environmentally Important Trace Elements discusses fate, transport, and transformation in soils, waters, and plants in biogeochemistry of environmentally important trace elements, with a focus on arsenic, mercury, and selenium.