Download or read book Calcium Carbonate Formation in Energy related Subsurface Environments and Engineered Systems written by Qingyun Li and published by . This book was released on 2016 with total page 230 pages. Available in PDF, EPUB and Kindle. Book excerpt: Geologic CO2 sequestration (GCS) in subsurface saline aquifers is a promising strategy to mitigate climate change caused by increasing anthropogenic CO2 emissions from energy production. At GCS sites, interactions between fluids and geomedia are important because they can affect CO2 trapping efficiency and the safety of CO2 storage. These interactions include the dissolution and precipitation of minerals. One of the most important minerals is calcium carbonate, because it can permanently trap CO2.In this work, Portland cement was used as a model geomedium to investigate the chemical reactions, mechanical alterations, transport of reactive fluids, and the interplay of all these aspects. Also, because Portland cement is used in building and decommissioning CO2 injection wells, its alteration is important for wellbore integrity. Wellbore cement can deteriorate as a result of extensive reactions with injected CO2. Typically, a carbonated layer forms, which can partially reduce CO2 attack by clogging pores in the cement. We conducted high temperature/pressure experiments using Portland cement paste samples, and after 10 days of reaction, quantified the chemical changes using scanning electron microscope backscattering electron imaging and X-ray diffraction. The mechanical changes were quantified as well using a three-point bending setup and nanoindentation. The experimental results showed that after CO2 attack, the cement samples decreased in strength by ~80%, and this decrease was closely related to the formation of a wide and weak portlandite-depleted zone in the cement matrix immediately inside of the carbonated layer. The effects of 0.05 M of sulfate ions were also examined. Interestingly, the additional sulfate ions were found to mitigate CO2 attack by forming a more protective and less soluble carbonated layer, and thus a thinner portlandite-depleted zone.To further investigate the detailed mechanisms by which the wide and weak portlandite-depleted zone formed and the carbonated layer's surface dissolved, we set up a one-dimensional continuum reactive transport model using the CrunchTope software. Two mechanisms were found to be critical in reproducing our main observations: First, the precipitated CaCO3 could not fill the entire pore spaces in the carbonated layer. The inefficiency of CaCO3 precipitation in filling all the pores might be due to fractures and defects in the carbonated layer, or due to the extent of pore-size-dependent precipitation. Second, nucleation kinetics had to be incorporated into the model to predict the mineral precipitation observed in the reaction solution and to capture the dissolution of the carbonated layer's surface.To acquire parameters for the incorporation of nucleation kinetics, CaCO3 nucleation experiments were conducted primarily using atomic force microscopy and synchrotron-based in situ grazing incidence small angle X-ray scattering. Newly obtained interfacial energies were compared for mica and quartz systems, and a slightly higher interfacial energy was found in the quartz system. The effects of salinity were investigated in the range of 0.15--0.85 M ionic strengths, and we found a decrease of interfacial energies at high salinity. The kinetic factors, including the apparent activation energy and the pre-exponential factor in the nucleation rate equation, were experimentally obtained for the first time by varying temperatures in the range of 12--31 °C. These parameters provided the key information for modeling nucleation in geomedia and synthesizing well controlled materials in materials science.The CaCO3 nucleation studies advanced our current understanding of nucleation under various conditions, and the acquired parameters were indispensable for our numerical simulations of the cement deterioration. The reactive transport modeling work revealed the important mechanisms in the cement--CO2 reactions, and provided many insights for understanding the chemical and mechanical alterations of geomedia. The investigation of cement deterioration quantitatively coupled the chemical and mechanical changes of the cement samples, and proved that the molecular scale of water--rock reactions can have a substantial impact on the change of the bulk geomedia. Such information can be also be applied to shale/sandstone--CO2 interactions. Overall, this dissertation presents a platform to understand fluid--geomedia interactions, combining experimental and modeling approaches, and connecting basic sciences and real applications. The advanced understanding of fluid--geomedia interactions will help improve GCS operation and thus address the climate change challenge.

Download or read book Handbook of Porous Media written by Kambiz Vafai and published by CRC Press. This book was released on 2015-06-23 with total page 946 pages. Available in PDF, EPUB and Kindle. Book excerpt: Handbook of Porous Media, Third Edition offers a comprehensive overview of the latest theories on flow, transport, and heat-exchange processes in porous media. It also details sophisticated porous media models which can be used to improve the accuracy of modeling in a variety of practical applications. Featuring contributions from leading experts i

Download or read book Final Report for Grant Number DE FG02 06ER64244 to the University of Idaho RW Smith coupling Between Flow and Precipitation in Heterogeneous Subsurface Environments and Effects on Contaminant Fate and Transport written by and published by . This book was released on 2010 with total page 14 pages. Available in PDF, EPUB and Kindle. Book excerpt: Engineered remediation strategies for inducing mineral precipitation in the subsurface typically involve the introduction of at least one reactant either by direct injection or by in situ generation. The localization of reactant sources means a wide range of saturation states and ion ratios will be created as reactants are mixed: These conditions together can result in a wide range of precipitation rates, as well as impact which mineral phase precipitates. This is potentially important for the capacity of the precipitates to take up of trace metal contaminants, for their long term stability. Aragonite, for example, is able to sequester a larger amount of Sr than calcite. However, aragonite is less stable under typical groundwater conditions, and so may release sequestered Sr over time as the aragonite transforms to a more stable phase. In addition, previous experimental studies have indicated that other system constituents may influence calcium carbonate precipitation and consequently the Sr uptake potential of a system. For example, dissolved organic carbon (at levels typical of groundwaters) can suppress crystal growth. As a result, the continuous nucleation of small crystals, rather than growth of existing crystals, may be the dominant mode of precipitation. This has the potential for greater uptake of Sr because the smaller crystal sizes associated with nucleated calcite may more readily accommodate the distortion resulting from substitution of the larger Sr ion for Ca ions than can larger crystals. However, these smaller crystals may also be less stable and over the long term release Sr as a result of Ostwald ripening. To better understand the formation and composition of relevant calcium carbonate mineral phases two related series of mineral precipitation experiments were conducted. The first series of experiments, conducted using a Continuously Stirred Tank Reactor (CSTR) operated at steady state rates of precipitation was focused on understanding the influence of pH and ammonium carbonate (the hydrolysis product of urea: ureolytically driven calcium carbonate precipitation has been demonstrated to be a promising method of inducing mineral precipitation in the field) on calcium carbonate polymorph and Sr co-precipitation. The second series of experiments, conducted at constant pH and saturation state, was focused on understanding the influence of aqueous carbonate to calcium ratios on the precipitation rate of calcite. In 12 CSTR experiments (three pH levels, two ammonium carbonate levels, and two strontium levels) we found that lower pH values and ammonium carbonate concentration promoted the precipitation of calcite and the higher pH values and ammonium carbonate concentration promoted the precipitation of aragonite (as determined by X-ray diffraction). Overall, the rate of calcium carbonate precipitation increased with increasing pH and ammonium carbonate concentration, consistent with increasing values of Q/K. Intermediate conditions resulted in the precipitation of a mixture of calcite and aragonite. There was no discernible effect of strontium on the rate of precipitation or the phase precipitated. In our experiments we precipitated rhombohedral calcite, lath-shaped aragonite and inter-grown calcite-aragonite mixtures. Using Laser Ablation-Inductively Coupled Plasma-Mass Spectrometer we characterized the composition of solids from an experiment in which both calcite and aragonite precipitates were identified by X-ray diffraction. We found a range in composition from a high Sr and low Mg phase (inferred to be aragonite) to a coexisting lower Sr and higher but variable Mg phase (inferred to be calcite). Values of the distribution coefficient for strontium of 1.1 and 0.2 for aragonite and calcite, respectively were estimated from the data. These values compare to values of 1.1 and 0.1 for aragonite and calcite, respectively, determined from bulk analysis of precipitates from experiments in which only calcite or on ...

Download or read book Heterogeneous Nucleation and Growth of Nanoparticles at Environmental Interfaces written by and published by . This book was released on 2016 with total page 10 pages. Available in PDF, EPUB and Kindle. Book excerpt: Here, mineral nucleation is a phase transformation of aqueous components to solids with an accompanying creation of new surfaces. In this evolutional, yet elusive, process, nuclei often form at environmental interfaces, which provide remarkably reactive sites for heterogeneous nucleation and growth. Naturally occurring nucleation processes significantly contribute to the biogeochemical cycles of important components in the Earth's crust, such as iron and manganese oxide minerals and calcium carbonate. However, in recent decades, these cycles have been significantly altered by anthropogenic activities, which affect the aqueous chemistry and equilibrium of both surface and subsurface systems. These alterations can trigger the dissolution of existing minerals and formation of new nanoparticles (i.e., nucleation and growth) and consequently change the porosity and permeability of geomedia in subsurface environments. Newly formed nanoparticles can also actively interact with components in natural and engineered aquatic systems, including those posing a significant hazard such as arsenic. These interactions can bilaterally influence the fate and transport of both newly formed nanoparticles and aqueous components. Due to their importance in natural and engineered processes, heterogeneous nucleation at environmental interfaces has started to receive more attention. However, a lack of time-resolved in situ analyses makes the evaluation of heterogeneous nucleation challenging because the physicochemical properties of both the nuclei and surfaces significantly and dynamically change with time and aqueous chemistry. This Account reviews our in situ kinetic studies of the heterogeneous nucleation and growth behaviors of iron(III) (hydr)oxide, calcium carbonate, and manganese (hydr)oxide minerals in aqueous systems. In particular, we utilized simultaneous small-angle and grazing incidence small-angle X-ray scattering (SAXS/GISAXS) to investigate in situ and in real-time the effects of water chemistry and substrate identity on heterogeneously and homogeneously formed nanoscale precipitate size dimensions and total particle volume. Using this technique, we also provided a new platform for quantitatively comparing between heterogeneous and homogeneous nucleation and growth of nanoparticles and obtaining undiscovered interfacial energies between nuclei and surfaces. In addition, nanoscale surface characterization tools, such as in situ atomic force microscopy (AFM), were utilized to support and complement our findings. With these powerful nanoscale tools, we systematically evaluated the influences of environmentally abundant (oxy)anions and cations and the properties of environmental surfaces, such as surface charge and hydrophobicity. The findings, significantly enhanced by in situ observations, can lead to a more accurate prediction of the behaviors of nanoparticles in the environment and enable better control of the physicochemical properties of nanoparticles in engineered systems, such as catalytic reactions and energy storage.

Download or read book New and Future Developments in Catalysis written by Steven L Suib and published by Newnes. This book was released on 2013-07-11 with total page 659 pages. Available in PDF, EPUB and Kindle. Book excerpt: New and Future Developments in Catalysis is a package of books that compile the latest ideas concerning alternate and renewable energy sources and the role that catalysis plays in converting new renewable feedstock into biofuels and biochemicals. Both homogeneous and heterogeneous catalysts and catalytic processes will be discussed in a unified and comprehensive approach. There will be extensive cross-referencing within all volumes.This volume presents a complete picture of all carbon dioxide (CO2) sources, outlines the environmental concerns regarding CO2, and critically reviews all current CO2 activation processes. Furthermore, the volume discusses all future developments and gives a critical economic analysis of the various processes. Offers in-depth coverage of all catalytic topics of current interest and outlines future challenges and research areas A clear and visual description of all parameters and conditions, enabling the reader to draw conclusions for a particular case Outlines the catalytic processes applicable to energy generation and design of green processes

Download or read book Study of Factors Related to Magnetic Treatment of Calcium Carbonate Saturated Water written by Kevin M. Lambert and published by . This book was released on 1998 with total page 268 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Energy Research Abstracts written by and published by . This book was released on 1995 with total page 782 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Reactive Transport in Natural and Engineered Systems written by Jennifer Druhan and published by Walter de Gruyter GmbH & Co KG. This book was released on 2020-03-04 with total page 514 pages. Available in PDF, EPUB and Kindle. Book excerpt: Open system behavior is predicated on a fundamental relationship between the timescale over which mass is transported and the timescale over which it is chemically transformed. This relationship describes the basis for the multidisciplinary field of reactive transport (RT). In the 20 years since publication of Review in Mineralogy and Geochemistry volume 34: Reactive Transport in Porous Media, RT principles have expanded beyond early applications largely based in contaminant hydrology to become broadly utilized throughout the Earth Sciences. RT is now employed to address a wide variety of natural and engineered systems across diverse spatial and temporal scales, in tandem with advances in computational capability, quantitative imaging and reactive interface characterization techniques. The present volume reviews the diversity of reactive transport applications developed over the past 20 years, ranging from the understanding of basic processes at the nano- to micrometer scale to the prediction of Earth global cycling processes at the watershed scale. Key areas of RT development are highlighted to continue advancing our capabilities to predict mass and energy transfer in natural and engineered systems.

Download or read book New and Future Developments in Catalysis written by U. Burghaus and published by Elsevier Inc. Chapters. This book was released on 2013-07-11 with total page 37 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Ocean Acidification written by National Research Council and published by National Academies Press. This book was released on 2010-09-14 with total page 200 pages. Available in PDF, EPUB and Kindle. Book excerpt: The ocean has absorbed a significant portion of all human-made carbon dioxide emissions. This benefits human society by moderating the rate of climate change, but also causes unprecedented changes to ocean chemistry. Carbon dioxide taken up by the ocean decreases the pH of the water and leads to a suite of chemical changes collectively known as ocean acidification. The long term consequences of ocean acidification are not known, but are expected to result in changes to many ecosystems and the services they provide to society. Ocean Acidification: A National Strategy to Meet the Challenges of a Changing Ocean reviews the current state of knowledge, explores gaps in understanding, and identifies several key findings. Like climate change, ocean acidification is a growing global problem that will intensify with continued CO2 emissions and has the potential to change marine ecosystems and affect benefits to society. The federal government has taken positive initial steps by developing a national ocean acidification program, but more information is needed to fully understand and address the threat that ocean acidification may pose to marine ecosystems and the services they provide. In addition, a global observation network of chemical and biological sensors is needed to monitor changes in ocean conditions attributable to acidification.

Download or read book A Study of Calcium Carbonate Formation in Biological Systems written by Stephen Barry Parker and published by . This book was released on 1983 with total page 714 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Applied and Environmental Microbiology written by and published by . This book was released on 2007 with total page 760 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Scientific and Technical Aerospace Reports written by and published by . This book was released on 1984 with total page 1278 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Negative Emissions Technologies and Reliable Sequestration written by National Academies of Sciences, Engineering, and Medicine and published by National Academies Press. This book was released on 2019-04-08 with total page 511 pages. Available in PDF, EPUB and Kindle. Book excerpt: To achieve goals for climate and economic growth, "negative emissions technologies" (NETs) that remove and sequester carbon dioxide from the air will need to play a significant role in mitigating climate change. Unlike carbon capture and storage technologies that remove carbon dioxide emissions directly from large point sources such as coal power plants, NETs remove carbon dioxide directly from the atmosphere or enhance natural carbon sinks. Storing the carbon dioxide from NETs has the same impact on the atmosphere and climate as simultaneously preventing an equal amount of carbon dioxide from being emitted. Recent analyses found that deploying NETs may be less expensive and less disruptive than reducing some emissions, such as a substantial portion of agricultural and land-use emissions and some transportation emissions. In 2015, the National Academies published Climate Intervention: Carbon Dioxide Removal and Reliable Sequestration, which described and initially assessed NETs and sequestration technologies. This report acknowledged the relative paucity of research on NETs and recommended development of a research agenda that covers all aspects of NETs from fundamental science to full-scale deployment. To address this need, Negative Emissions Technologies and Reliable Sequestration: A Research Agenda assesses the benefits, risks, and "sustainable scale potential" for NETs and sequestration. This report also defines the essential components of a research and development program, including its estimated costs and potential impact.

Download or read book Handbook of Environmental Engineering written by Frank R. Spellman and published by CRC Press. This book was released on 2015-09-08 with total page 750 pages. Available in PDF, EPUB and Kindle. Book excerpt: In his latest book, the Handbook of Environmental Engineering, esteemed author Frank Spellman provides a practical view of pollution and its impact on the natural environment. Driven by the hope of a sustainable future, he stresses the importance of environmental law and resource sustainability, and offers a wealth of information based on real-worl

Download or read book Environmental Engineering Dictionary and Directory written by Thomas M. Pankratz and published by CRC Press. This book was released on 2000-09-22 with total page 340 pages. Available in PDF, EPUB and Kindle. Book excerpt: Like most technical disciplines, environmental science and engineering is becoming increasingly specialized. As industry professionals focus on specific environmental subjects they become less familiar with environmental problems and solutions outside their area of expertise. This situation is compounded by the fact that many environmental science

Download or read book Special Edition Environmental Engineering Dictionary and Directory written by Thomas M. Pankratz and published by CRC Press. This book was released on 2000-09-22 with total page 339 pages. Available in PDF, EPUB and Kindle. Book excerpt: Like most technical disciplines, environmental science and engineering is becoming increasingly specialized. As industry professionals focus on specific environmental subjects they become less familiar with environmental problems and solutions outside their area of expertise. This situation is compounded by the fact that many environmental science