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Sample records for carbonate scaling minerals

  1. Probing carbonate in bone forming minerals on the nanometre scale.

    PubMed

    Kłosowski, Michał M; Friederichs, Robert J; Nichol, Robert; Antolin, Nikolas; Carzaniga, Raffaella; Windl, Wolfgang; Best, Serena M; Shefelbine, Sandra J; McComb, David W; Porter, Alexandra E

    2015-07-01

    To devise new strategies to treat bone disease in an ageing society, a more detailed characterisation of the process by which bone mineralises is needed. In vitro studies have suggested that carbonated mineral might be a precursor for deposition of bone apatite. Increased carbonate content in bone may also have significant implications in altering the mechanical properties, for example in diseased bone. However, information about the chemistry and coordination environment of bone mineral, and their spatial distribution within healthy and diseased tissues, is lacking. Spatially resolved analytical transmission electron microscopy is the only method available to probe this information at the length scale of the collagen fibrils in bone. In this study, scanning transmission electron microscopy combined with electron energy-loss spectroscopy (STEM-EELS) was used to differentiate between calcium-containing biominerals (hydroxyapatite, carbonated hydroxyapatite, beta-tricalcium phosphate and calcite). A carbon K-edge peak at 290 eV is a direct marker of the presence of carbonate. We found that the oxygen K-edge structure changed most significantly between minerals allowing discrimination between calcium phosphates and calcium carbonates. The presence of carbonate in carbonated HA (CHA) was confirmed by the formation of peak at 533 eV in the oxygen K-edge. These observations were confirmed by simulations using density functional theory. Finally, we show that this method can be utilised to map carbonate from the crystallites in bone. We propose that our calibration library of EELS spectra could be extended to provide spatially resolved information about the coordination environment within bioceramic implants to stimulate the development of structural biomaterials.

  2. Atom-scale insights into carbonate organic-mineral interfaces

    NASA Astrophysics Data System (ADS)

    Branson, O.; Perea, D. E.; Spero, H. J.; Winters, M. A.; Gagnon, A.

    2015-12-01

    Biominerals are formed by the complex interaction between guiding biological structures and the kinetics of inorganic mineral growth. Inorganic crystal growth experiments have advanced our understanding of mineral precipitation in the context of biological systems, but the structure and chemistry of the mineralizing interface between these two systems has remained elusive. We have used laser-pulsed Atom Probe Tomography to reveal the first atom-scale 3D view of an organic-mineral interface in calcite produced by the planktic foraminifera Orbulina universa. We observe elevated Na and Mg throughout the organic, and a 9-fold increase in Na in the surface 2 nm of the organic layer, relative to the adjacent calcite. The surface-specificity of this Na maximum suggests that Na may play an integral role in conditioning the organic layer for calcite nucleation. Na could accomplish this by modifying surface hydration or structure, to modify organic-fluid and/or organic-calcite interfacial energies. Our data constitute the first evidence of the role of 'spectator' ions in facilitating biomineralisation, which could be an overlooked but crucial aspect of the initial steps of skeleton formation in calcifying organisms.

  3. Mineralization of allochthonous organic carbon in lake sediments, from lake to landscape scale

    NASA Astrophysics Data System (ADS)

    Gudasz, C.; Ask, J.; Tranvik, L. J.; Karlsson, J.

    2012-04-01

    Lake sediments are well-recognized sites for the processing as well as sequestration of organic carbon. In particular boreal lake sediments have been recognized as important sites for the sequestration of organic carbon, comparable to soils or living biomass. Lakes in the boreal zone import large amounts of terrestrially derived organic carbon. Part of this organic carbon reaches the sediment surface through flocculation and sedimentation. The microbial processing of organic carbon represents one of the main factors that regulate the balance between sequestration of organic carbon and emission of green house gasses in boreal lake sediments. Recently, it has been shown a strong constrained microbial processing of allochthonous organic carbon in boreal lake sediments. However, a clear picture about the extent of the allochthonous organic carbon influence on the mineralization of sediment organic carbon in lakes and its significance at a large scale is currently lacking. We conducted a study, which explored the effect of allochthonous organic carbon on sediment organic carbon mineralization along a gradient of lakes characterized by increasing terrestrial organic carbon influence. We show a strong negative effect on sediment mineralization in lakes with increasing allochthonous organic carbon influence, which applies to a large number of lakes in the boreal zone.

  4. What Are the Time Scales for Carbonate Mineral Sequestration in the Subsurface?

    NASA Astrophysics Data System (ADS)

    Steefel, C. I.; Landrot, G.; Bolton, E. W.; Pride, S. R.

    2013-12-01

    Mineral trapping of CO2 in the subsurface is acknowledged to be the most secure form of sequestration, but some studies have suggested that the process is extremely slow, perhaps on the order of 10,000 years or more. But what are the arguments for these long time scales based on? Certainly part of it has to do with the slow dissolution rates of silicates needed to provide a source of cations (Ca2+, Mg2+, and Fe2+) and alkalinity for carbonate precipitation. Rates of dissolution for many silicates are very slow (e.g., albitic plagioclase and chlorite), while other silicate minerals (anorthitic feldspar, olivine) dissolve appreciably faster. Determining which mineral is rate-limiting in the case of the faster dissolving silicates (is it the dissolving silicate or precipitating carbonate?), however, is not always straightforward without a careful analysis of dissolution and precipitation as a coupled process. We use micro-continuum modeling to address the issue of time scales for carbonate mineral trapping of CO2. Two sets of simulations have been carried out: 1) largely generic simulations at the centimeter scale that include heterogeneous distributions of both residually trapped scCO2 and reactive mineral phases (Ca-bearing plagioclase and chlorite), and 2) flow plus diffusion and pure diffusion simulations of the reactivity of a reservoir sandstone from a scCO2 pilot injection site at Cranfield, Mississippi. The first set of simulations are designed specifically to examine the assumption that the reservoir within which carbonate mineral precipitation might occur is well-mixed and therefore characterized everywhere by the low pH values typical of brine in equilibrium with supercritical CO2. Our analysis of physically and chemically heterogeneous subsurface materials, especially during the residual trapping stage, suggest that local chemical microenvironments can develop in which pH, alkalinity, and cation concentrations rise sufficiently high that substantial

  5. Electrochemical mineral scale prevention and removal on electrically conducting carbon nanotube--polyamide reverse osmosis membranes.

    PubMed

    Duan, Wenyan; Dudchenko, Alexander; Mende, Elizabeth; Flyer, Celeste; Zhu, Xiaobo; Jassby, David

    2014-05-01

    The electrochemical prevention and removal of CaSO4 and CaCO3 mineral scales on electrically conducting carbon nanotube - polyamide reverse osmosis membrane was investigated. Different electrical potentials were applied to the membrane surface while filtering model scaling solutions with high saturation indices. Scaling progression was monitored through flux measurements. CaCO3 scale was efficiently removed from the membrane surface through the intermittent application of a 2.5 V potential to the membrane surface, when the membrane acted as an anode. Water oxidation at the anode, which led to proton formation, resulted in the dissolution of deposited CaCO3 crystals. CaSO4 scale formation was significantly retarded through the continuous application of 1.5 V DC to the membrane surface, when the membrane was operated as an anode. The continuous application of a sufficient electrical potential to the membrane surface leads to the formation of a thick layer of counter-ions along the membrane surface that pushed CaSO4 crystal formation away from the membrane surface, allowing the formed crystals to be carried away by the cross-flow. We developed a simple model, based on a modified Poisson-Boltzmann equation, which qualitatively explained our observed experimental results.

  6. Ex situ aqueous mineral carbonation.

    PubMed

    Gerdemann, Stephen J; O'Connor, William K; Dahlin, David C; Penner, Larry R; Rush, Hank

    2007-04-01

    The U.S. Department of Energy's National Energy Technology Laboratory (NETL) located in Albany, OR (formerly the Albany Research Center) has studied ex situ mineral carbonation as a potential option for carbon dioxide sequestration. Studies focused on the reaction of Ca-, Fe-, and Mg-silicate minerals with gaseous CO2 to form geologically stable, naturally occurring solid carbonate minerals. The research included resource evaluation, kinetic studies, process development, and economic evaluation. An initial cost estimate of approximately $69/ton of CO2 sequestered was improved with process improvements to $54/ton. The scale of ex situ mineral carbonation operations, requiring 55 000 tons of mineral to carbonate, the daily CO2 emissions from a 1-GW, coal-fired power plant, may make such operations impractical.

  7. Ex Situ Aqueous Mineral Carbonation

    SciTech Connect

    Gerdemann, S.J.; O'Connor, W.K.; Dahlin, D.C.; Penner, L.R.; Rush, G.E.

    2007-04-01

    The U.S. Department of Energy's National Energy Technology Laboratory (NETL) located in Albany, OR (formerly the Albany Research Center) has studied ex situ mineral carbonation as a potential option for carbon dioxide sequestration. Studies focused on the reaction of Ca-, Fe-, and Mg-silicate minerals with gaseous CO2 to form geologically stable, naturally occurring solid carbonate minerals. The research included resource evaluation, kinetic studies, process development, and economic evaluation. An initial cost estimate of ~$69/ton of CO2 sequestered was improved with process improvements to ~$54/ton. The scale of ex situ mineral carbonation operations, requiring ~55 000 tons of mineral to carbonate, the daily CO2 emissions from a 1-GW, coal-fired power plant, may make such operations impractical.

  8. Ex situ aqueous mineral carbonation

    SciTech Connect

    Stephen J. Gerdemann; William K. O'Connor; David C. Dahlin; Larry R. Penner; Hank Rush

    2007-04-01

    The U.S. Department of Energy's National Energy Technology Laboratory (NETL) located in Albany, OR (formerly the Albany Research Center) has studied ex situ mineral carbonation as a potential option for carbon dioxide sequestration. Studies focused on the reaction of Ca-, Fe-, and Mg-silicate minerals with gaseous CO{sub 2} to form geologically stable, naturally occurring solid carbonate minerals. The research included resource evaluation, kinetic studies, process development, and economic evaluation. An initial cost estimate of about $69/ton of CO{sub 2} sequestered was improved with process improvements to about 54/ton. The scale of ex situ mineral carbonation operations, requiring about 55,000 tons of mineral to carbonate, the daily CO{sub 2} emissions from a 1-GW, coal-fired power plant, may make such operations impractical. 23 refs., 4 figs., 5 tabs.

  9. Mesocosm-Scale Experimental Quantification of Plant-Fungi Associations on Carbon Fluxes and Mineral Weathering

    NASA Astrophysics Data System (ADS)

    Andrews, M. Y.; Palmer, B.; Leake, J. R.; Banwart, S. A.; Beerling, D. J.

    2009-12-01

    The rise of land plants in the Paleozoic is classically implicated as driving lower atmospheric CO2 levels through enhanced weathering of Ca and Mg bearing silicate minerals. However, this view overlooks the fact that plants coevolved with associated mycorrhizal fungi over this time, with many of the weathering processes usually ascribed to plants actually being driven by the combined activities of roots and mycorrhizal fungi. Here we present initial results from a novel mesocosm-scale laboratory experiment designed to allow investigation of plant-driven carbon flux and mineral weathering at different soil depths under ambient (400 ppm) and elevated (1500 ppm) atmospheric CO2. Four species of plants were chosen to address evolutionary trends in symbiotic mycorrhizal association and rooting depth on biologically driven silicate weathering under the different CO2 regimes. Gymnosperms were used to investigate potential differences in weathering capabilities of two fungal symbioses: Sequoia sempervirens and Metasequoia glyptostroboides (arbuscular mycorrhizal, AM) and Pinus sylvestris (ectomycorrhizal, EM), and the shallow rooted ancient fern, Osmunda regalis, used to provide a contrast to the three more deeply rooted trees. Plants were grown in a cylindrical mesocosm with four horizontal inserts at each depth. These inserts are a mesh-covered dual-core unit whereby an inner core containing silicate minerals can be rotated within an outer core. The mesh excludes roots from the cylinders allowing fungal-rock pairings to be examined at each depth. Each core contains either basalt or granite, each with severed (rotated cores) or intact (static cores) mycorrhizae. This system provides a unique opportunity to examine the ability of a plant to weather minerals with and without its symbiotic fungi. Preliminary results indicate marked differences in nutritional and water requirements, and response to elevated CO2 between the species. The bulk solution chemistries (p

  10. Microbially mediated mineral carbonation

    NASA Astrophysics Data System (ADS)

    Power, I. M.; Wilson, S. A.; Dipple, G. M.; Southam, G.

    2010-12-01

    Mineral carbonation involves silicate dissolution and carbonate precipitation, which are both natural processes that microorganisms are able to mediate in near surface environments (Ferris et al., 1994; Eq. 1). (Ca,Mg)SiO3 + 2H2CO3 + H2O → (Ca,Mg)CO3 + H2O + H4SiO4 + O2 (1) Cyanobacteria are photoautotrophs with cell surface characteristics and metabolic processes involving inorganic carbon that can induce carbonate precipitation. This occurs partly by concentrating cations within their net-negative cell envelope and through the alkalinization of their microenvironment (Thompson & Ferris, 1990). Regions with mafic and ultramafic bedrock, such as near Atlin, British Columbia, Canada, represent the best potential sources of feedstocks for mineral carbonation. The hydromagnesite playas near Atlin are a natural biogeochemical model for the carbonation of magnesium silicate minerals (Power et al., 2009). Field-based studies at Atlin and corroborating laboratory experiments demonstrate the ability of a microbial consortium dominated by filamentous cyanobacteria to induce the precipitation of carbonate minerals. Phototrophic microbes, such as cyanobacteria, have been proposed as a means for producing biodiesel and other value added products because of their efficiency as solar collectors and low requirement for valuable, cultivable land in comparison to crops (Dismukes et al., 2008). Carbonate precipitation and biomass production could be facilitated using specifically designed ponds to collect waters rich in dissolved cations (e.g., Mg2+ and Ca2+), which would allow for evapoconcentration and provide an appropriate environment for growth of cyanobacteria. Microbially mediated carbonate precipitation does not require large quantities of energy or chemicals needed for industrial systems that have been proposed for rapid carbon capture and storage via mineral carbonation (e.g., Lackner et al., 1995). Therefore, this biogeochemical approach may represent a readily

  11. Carbon Mineral Ecology: Predicting the Undiscovered Minerals of Carbon

    NASA Astrophysics Data System (ADS)

    Hazen, R. M.; Hummer, D. R.; Downs, R. T.; Hystad, G.; Golden, J.

    2015-12-01

    The diversity and distribution of Earth's minerals through deep time reflects key events in our planet's crustal evolution. Studies in mineral ecology exploit mineralogical databases to document diversity-distribution relationships of minerals, which reveal that all carbon-bearing minerals, as well as subsets containing C with O, H, Ca, or Na, conform to Large Number of Rare Events (LNRE) distributions. LNRE models facilitate prediction of total mineral diversity, and thus point to minerals that exist on Earth but have not yet been discovered and described. Our model predicts that at least 548 C minerals exist on Earth today, indicating that at least 145 carbon-bearing mineral species have yet to be discovered. Furthermore, by analyzing subsets of the most common additional elements in carbon-bearing minerals (i.e., 378 C + O species; 282 C + H species; 133 C + Ca species; and 100 C + Na species), we predict that 129 of these missing carbon minerals contain oxygen, 118 contain hydrogen, 52 contain calcium, and more than 60 contain sodium. The majority of these as yet undescribed minerals are predicted to be hydrous carbonates, many of which may have been overlooked because they are colorless, poorly crystalized, and/or water-soluble. We propose the identities of plausible as yet undescribed carbon minerals, as well as search strategies for their discovery. Some of these minerals will be natural examples of known synthetic compounds, including carbides such as calcium carbide (CaC2), crystalline hydrocarbons such as pyrene (C16H10), and numerous oxalates, anhydrous carbonates, and hydrous carbonates. Many other missing carbon minerals will be isomorphs of known carbon minerals, notably of the more than 100 different hydrous carbonate structures. An understanding of Earth's "missing" minerals provides a more complete picture of geochemical processes that influence crustal evolution.

  12. Assessment of grain-scale homogeneity and equilibration of carbon and oxygen isotope compositions of minerals in carbonate-bearing metamorphic rocks by ion microprobe

    NASA Astrophysics Data System (ADS)

    Ferry, John M.; Ushikubo, Takayuki; Kita, Noriko T.; Valley, John W.

    2010-11-01

    Nineteen samples of metamorphosed carbonate-bearing rocks were analyzed for carbon and oxygen isotope ratios by ion microprobe with a ˜5-15 μm spot, three from a regional terrain and 16 from five different contact aureoles. Contact metamorphic rocks further represent four groups: calc-silicate marble and hornfels (6), brucite marble (2), samples that contain a reaction front (4), and samples with a pervasive distribution of reactants and products of a decarbonation reaction (4). The average spot-to-spot reproducibility of standard calcite analyses is ±0.37‰ (2 standard deviations, SD) for δ 18O and ±0.71‰ for δ 13C. Ten or more measurements of a mineral in a sample that has uniform isotope composition within error of measurement can routinely return a weighted mean with a 95% confidence interval of 0.09-0.16‰ for δ 18O and 0.10-0.29‰ for δ 13C. Using a difference of >6SD as the criterion, only four of 19 analyzed samples exhibit significant intracrystalline and/or intercrystalline inhomogeneity in δ 13C at the 100-500 μm scale, with differences within individual grains up to 3.7‰. Measurements are consistent with carbon isotope exchange equilibrium between calcite and dolomite in five of six analyzed samples at the same scale. Because of relatively slow carbon isotope diffusion in calcite and dolomite, differences in δ 13C can survive intracrystalline homogenization by diffusion during cooling after peak metamorphism and likely represent the effects of prograde decarbonation and infiltration. All but 2 of 11 analyzed samples exhibit intracrystalline differences in δ 18O (up to 9.4‰), intercrystalline inhomogeneity in δ 18O (up to 12.5‰), and/or disequilibrium oxygen isotope fractionations among calcite-dolomite, calcite-quartz, and calcite-forsterite pairs at the 100-500 μm scale. Inhomogeneities in δ 18O and δ 13C are poorly correlated with only a single mineral (dolomite) in a single sample exhibiting both. Because of relatively

  13. Accelerating Mineral Carbonation Using Carbonic Anhydrase.

    PubMed

    Power, Ian M; Harrison, Anna L; Dipple, Gregory M

    2016-03-01

    Carbonic anhydrase (CA) enzymes have gained considerable attention for their potential use in carbon dioxide (CO2) capture technologies because they are able to catalyze rapidly the interconversion of aqueous CO2 and bicarbonate. However, there are challenges for widespread implementation including the need to develop mineralization process routes for permanent carbon storage. Mineral carbonation of highly reactive feedstocks may be limited by the supply rate of CO2. This rate limitation can be directly addressed by incorporating enzyme-catalyzed CO2 hydration. This study examined the effects of bovine carbonic anhydrase (BCA) and CO2-rich gas streams on the carbonation rate of brucite [Mg(OH)2], a highly reactive mineral. Alkaline brucite slurries were amended with BCA and supplied with 10% CO2 gas while aqueous chemistry and solids were monitored throughout the experiments (hours to days). In comparison to controls, brucite carbonation using BCA was accelerated by up to 240%. Nesquehonite [MgCO3·3H2O] precipitation limited the accumulation of hydrated CO2 species, apparently preventing BCA from catalyzing the dehydration reaction. Geochemical models reproduce observed reaction progress in all experiments, revealing a linear correlation between CO2 uptake and carbonation rate. Data demonstrates that carbonation in BCA-amended reactors remained limited by CO2 supply, implying further acceleration is possible.

  14. Accelerating Mineral Carbonation Using Carbonic Anhydrase.

    PubMed

    Power, Ian M; Harrison, Anna L; Dipple, Gregory M

    2016-03-01

    Carbonic anhydrase (CA) enzymes have gained considerable attention for their potential use in carbon dioxide (CO2) capture technologies because they are able to catalyze rapidly the interconversion of aqueous CO2 and bicarbonate. However, there are challenges for widespread implementation including the need to develop mineralization process routes for permanent carbon storage. Mineral carbonation of highly reactive feedstocks may be limited by the supply rate of CO2. This rate limitation can be directly addressed by incorporating enzyme-catalyzed CO2 hydration. This study examined the effects of bovine carbonic anhydrase (BCA) and CO2-rich gas streams on the carbonation rate of brucite [Mg(OH)2], a highly reactive mineral. Alkaline brucite slurries were amended with BCA and supplied with 10% CO2 gas while aqueous chemistry and solids were monitored throughout the experiments (hours to days). In comparison to controls, brucite carbonation using BCA was accelerated by up to 240%. Nesquehonite [MgCO3·3H2O] precipitation limited the accumulation of hydrated CO2 species, apparently preventing BCA from catalyzing the dehydration reaction. Geochemical models reproduce observed reaction progress in all experiments, revealing a linear correlation between CO2 uptake and carbonation rate. Data demonstrates that carbonation in BCA-amended reactors remained limited by CO2 supply, implying further acceleration is possible. PMID:26829491

  15. Carbon dioxide sequestration by mineral carbonation

    SciTech Connect

    Gerdemann, Stephen J.; Dahlin David C.; O'Connor William K.; Penner Larry R.

    2003-11-01

    Concerns about global warming caused by the increasing concentration of carbon dioxide and other greenhouse gases in the earth’s atmosphere have resulted in the need for research to reduce or eliminate emissions of these gases. Carbonation of magnesium and calcium silicate minerals is one possible method to achieve this reduction. It is possible to carry out these reactions either in situ (storage underground and subsequent reaction with the host rock to trap CO2 as carbonate minerals) or ex situ (above ground in a more traditional chemical processing plant). Research at the Department of Energy’s Albany Research Center has explored both of these routes. This paper will explore parameters that affect the direct carbonation of magnesium silicate minerals serpentine (Mg3Si2O5(OH)4) and olivine (Mg2SiO4) to produce magnesite (MgCO3), as well as the calcium silicate mineral, wollastonite (CaSiO3), to form calcite (CaCO3). The Columbia River Basalt Group is a multi-layered basaltic lava plateau that has favorable mineralogy and structure for storage of CO2. Up to 25% combined concentration of Ca, Fe2+, and Mg cations could react to form carbonates and thus sequester large quantities of CO2. Core samples from the Columbia River Basalt Group were reacted in an autoclave for up to 2000 hours at temperatures and pressures to simulate in situ conditions. Changes in core porosity, secondary minerals, and solution chemistry were measured.

  16. Reactor design considerations in mineral sequestration of carbon dioxide

    SciTech Connect

    Ityokumbul, M.T.; Chander, S.; O'Connor, William K.; Dahlin, David C.; Gerdemann, Stephen J.

    2001-01-01

    One of the promising approaches to lowering the anthropogenic carbon dioxide levels in the atmosphere is mineral sequestration. In this approach, the carbon dioxide reacts with alkaline earth containing silicate minerals forming magnesium and/or calcium carbonates. Mineral carbonation is a multiphase reaction process involving gas, liquid and solid phases. The effective design and scale-up of the slurry reactor for mineral carbonation will require careful delineation of the rate determining step and how it changes with the scale of the reactor. The shrinking core model was used to describe the mineral carbonation reaction. Analysis of laboratory data indicates that the transformations of olivine and serpentine are controlled by chemical reaction and diffusion through an ash layer respectively. Rate parameters for olivine and serpentine carbonation are estimated from the laboratory data.

  17. Estimation of palaeohydrochemical conditions using carbonate minerals

    NASA Astrophysics Data System (ADS)

    Amamiya, H.; Mizuno, T.; Iwatsuki, T.; Yuguchi, T.; Murakami, H.; Saito-Kokubu, Y.

    2014-12-01

    The long-term evolution of geochemical environment in deep underground is indispensable research subject for geological disposal of high-level radioactive waste, because the evolution of geochemical environment would impact migration behavior of radionuclides in deep underground. Many researchers have made efforts previously to elucidate the geochemical environment within the groundwater residence time based on the analysis of the actual groundwater. However, it is impossible to estimate the geochemical environment for the longer time scale than the groundwater residence time in this method. In this case, analysis of the chemical properties of secondary minerals are one of useful method to estimate the paleohydrochemical conditions (temperature, salinity, pH and redox potential). In particular, carbonate minerals would be available to infer the long-term evolution of hydrochemical for the following reasons; -it easily reaches chemical equilibrium with groundwater and precipitates in open space of water flowing path -it reflects the chemical and isotopic composition of groundwater at the time of crystallization We reviewed the previous studies on carbonate minerals and geochemical conditions in deep underground and estimated the hydrochemical characteristics of past groundwater by using carbonate minerals. As a result, it was found that temperature and salinity of the groundwater during crystallization of carbonate minerals were evaluated quantitatively. On the other hand, pH and redox potential can only be understood qualitatively. However, it is suggested that the content of heavy metal elements such as manganese, iron and uranium, and rare earth elements in the carbonate minerals are useful indicators for estimating redox potential. This study was carried out under a contract with METI (Ministry of Economy, Trade and Industry) as part of its R&D supporting program for developing geological disposal technology.

  18. Carbon dioxide sequestration by direct aqueous mineral carbonation

    SciTech Connect

    O'Connor, William K.; Dahlin, David C.; Nilsen, David N.; Walters, Richard P.; Turner, Paul C.

    2000-01-01

    Carbon dioxide sequestration by an ex-situ, direct aqueous mineral carbonation process has been investigated over the past two years. This process was conceived to minimize the steps in the conversion of gaseous CO2 to a stable solid. This meant combining two separate reactions, mineral dissolution and carbonate precipitation, into a single unit operation. It was recognized that the conditions favorable for one of these reactions could be detrimental to the other. However, the benefits for a combined aqueous process, in process efficiency and ultimately economics, justified the investigation. The process utilizes a slurry of water, dissolved CO2, and a magnesium silicate mineral, such as olivine [forsterite end member (Mg2SiO4)], or serpentine [Mg3Si2O5(OH)4]. These minerals were selected as the reactants of choice for two reasons: (1) significant abundance in nature; and (2) high molar ratio of the alkaline earth oxides (CaO, MgO) within the minerals. Because it is the alkaline earth oxide that combines with CO2 to form the solid carbonate, those minerals with the highest ratio of these oxides are most favored. Optimum results have been achieved using heat pretreated serpentine feed material, sodium bicarbonate and sodium chloride additions to the solution, and high partial pressure of CO2 (PCO2). Specific conditions include: 155?C; PCO2=185 atm; 15% solids. Under these conditions, 78% conversion of the silicate to the carbonate was achieved in 30 minutes. Future studies are intended to investigate various mineral pretreatment options, the carbonation solution characteristics, alternative reactants, scale-up to a continuous process, geochemical modeling, and process economics.

  19. Factors affecting ex-situ aqueous mineral carbonation using calcium and magnesium silicate minerals

    SciTech Connect

    Gerdemann, Stephen J.; Dahlin, David C.; O'Connor, William K.; Penner, Larry R.; Rush, G.E.

    2004-01-01

    Carbonation of magnesium- and calcium-silicate minerals to form their respective carbonates is one method to sequester carbon dioxide. Process development studies have identified reactor design as a key component affecting both the capital and operating costs of ex-situ mineral sequestration. Results from mineral carbonation studies conducted in a batch autoclave were utilized to design and construct a unique continuous pipe reactor with 100% recycle (flow-loop reactor). Results from the flow-loop reactor are consistent with batch autoclave tests, and are being used to derive engineering data necessary to design a bench-scale continuous pipeline reactor.

  20. Energy and economic evaluation of ex situ aqueous mineral carbonation

    SciTech Connect

    O'Connor, William K.; Dahlin, David C.; Rush, Gilbert E.; Gerdemann, Stephen J.; Penner, Larry R.

    2004-09-01

    Aqueous mineral carbonation has been studied at the Albany Research Center as a potential option for CO2 sequestration. Studies have focused on the reaction of Ca-, Fe-, and Mg-silicate minerals with gaseous CO2 to form geologically stable, naturally occurring solid carbonate minerals. Process development has progressed in parallel with a process evaluation study, which was conducted for a mineral carbonation unit scaled to sequester 100% of the CO2 emissions from a 1.3 GW coal-fired power plant. The carbonation plant would require roughly 55 kt/day of mineral reactant to carbonate about 24 kt/day of CO2. The overall cost estimate was approximately $54(US)/ton CO2 sequestered. The power requirement determined for the mineral carbonation unit was about 352 MW, which represents 27% of the net power plant output. Improved mineral pretreatment and reactor design indicate that costs could be reduced by improvements to the reaction efficiency. However, because the material balance is dependent on the stoichiometry of the reaction, the chemistry of the silicate ore reactants, as well as the rection efficiency, the silicate ore demand cannot be reduced beyond a theoretical ratio of about 2:1, silicate ore to CO2. Based on these factors, mineral carbonation may be best suited as a niche option for sequestration, where CO2 point sources coincide with sources of the desired mineral reactants, and may also favor an in situ methodology. Laboratory studies of in situ carbonation have shown promise.

  1. Nitrogen mineralization and assimilation at millimeter scales.

    PubMed

    Myrold, David D; Pett-Ridge, Jennifer; Bottomley, Peter J

    2011-01-01

    The assimilation (uptake or immobilization) of inorganic nitrogen (N) and the production of ammonium (NH(4)(+)) from organic N compounds are universal functions of microorganisms, and the balance between these two processes is tightly regulated by the relative demands of microbes for N and carbon (C). In a heterogeneous environment, such as soils, bulk measurements of N mineralization or immobilization do not reflect the variation of these two processes in different microhabitats (1μm-1mm). Our purpose is to review the approaches that can be applied to measure N mineralization and immobilization within soil microhabitats, at scales of millimeter (using adaptations of (15)N isotope pool dilution and IRMS-isotope ratio mass spectrometry) to micrometer (using SIMS-secondary ion mass spectrometry). PMID:21514461

  2. Characterization of reactive flow-induced evolution of carbonate rocks using digital core analysis- part 1: Assessment of pore-scale mineral dissolution and deposition.

    PubMed

    Qajar, Jafar; Arns, Christoph H

    2016-09-01

    The application of X-ray micro-computed tomography (μ-CT) for quantitatively characterizing reactive-flow induced pore structure evolution including local particle detachment, displacement and deposition in carbonate rocks is investigated. In the studies conducted in this field of research, the experimental procedure has involved alternating steps of imaging and ex-situ core sample alteration. Practically, it is impossible to return the sample, with micron precision, to the same position and orientation. Furthermore, successive images of a sample in pre- and post-alteration states are usually taken at different conditions such as different scales, resolutions and signal-to-noise ratios. These conditions accompanying with subresolution features in the images make voxel-by-voxel comparisons of successive images problematic. In this paper, we first address the respective challenges in voxel-wise interpretation of successive images of carbonate rocks subject to reactive flow. Reactive coreflood in two carbonate cores with different rock types are considered. For the first rock, we used the experimental and imaging results published by Qajar et al. (2013) which showed a quasi-uniform dissolution regime. A similar reactive core flood was conducted in the second rock which resulted in wormhole-like dissolution regime. We particularly examine the major image processing operations such as transformation of images to the same grey-scale, noise filtering and segmentation thresholding and propose quantitative methods to evaluate the effectiveness of these operations in voxel-wise analysis of successive images of a sample. In the second part, we generalize the methodology based on the three-phase segmentation of normalized images, microporosity assignment and 2D histogram of image intensities to estimate grey-scale changes of individual image voxels for a general case where the greyscale images are segmented into arbitrary number of phases. The results show that local (voxel

  3. Characterization of reactive flow-induced evolution of carbonate rocks using digital core analysis- part 1: Assessment of pore-scale mineral dissolution and deposition

    NASA Astrophysics Data System (ADS)

    Qajar, Jafar; Arns, Christoph H.

    2016-09-01

    The application of X-ray micro-computed tomography (μ-CT) for quantitatively characterizing reactive-flow induced pore structure evolution including local particle detachment, displacement and deposition in carbonate rocks is investigated. In the studies conducted in this field of research, the experimental procedure has involved alternating steps of imaging and ex-situ core sample alteration. Practically, it is impossible to return the sample, with micron precision, to the same position and orientation. Furthermore, successive images of a sample in pre- and post-alteration states are usually taken at different conditions such as different scales, resolutions and signal-to-noise ratios. These conditions accompanying with subresolution features in the images make voxel-by-voxel comparisons of successive images problematic. In this paper, we first address the respective challenges in voxel-wise interpretation of successive images of carbonate rocks subject to reactive flow. Reactive coreflood in two carbonate cores with different rock types are considered. For the first rock, we used the experimental and imaging results published by Qajar et al. (2013) which showed a quasi-uniform dissolution regime. A similar reactive core flood was conducted in the second rock which resulted in wormhole-like dissolution regime. We particularly examine the major image processing operations such as transformation of images to the same grey-scale, noise filtering and segmentation thresholding and propose quantitative methods to evaluate the effectiveness of these operations in voxel-wise analysis of successive images of a sample. In the second part, we generalize the methodology based on the three-phase segmentation of normalized images, microporosity assignment and 2D histogram of image intensities to estimate grey-scale changes of individual image voxels for a general case where the greyscale images are segmented into arbitrary number of phases. The results show that local (voxel

  4. Characterization of reactive flow-induced evolution of carbonate rocks using digital core analysis- part 1: Assessment of pore-scale mineral dissolution and deposition.

    PubMed

    Qajar, Jafar; Arns, Christoph H

    2016-09-01

    The application of X-ray micro-computed tomography (μ-CT) for quantitatively characterizing reactive-flow induced pore structure evolution including local particle detachment, displacement and deposition in carbonate rocks is investigated. In the studies conducted in this field of research, the experimental procedure has involved alternating steps of imaging and ex-situ core sample alteration. Practically, it is impossible to return the sample, with micron precision, to the same position and orientation. Furthermore, successive images of a sample in pre- and post-alteration states are usually taken at different conditions such as different scales, resolutions and signal-to-noise ratios. These conditions accompanying with subresolution features in the images make voxel-by-voxel comparisons of successive images problematic. In this paper, we first address the respective challenges in voxel-wise interpretation of successive images of carbonate rocks subject to reactive flow. Reactive coreflood in two carbonate cores with different rock types are considered. For the first rock, we used the experimental and imaging results published by Qajar et al. (2013) which showed a quasi-uniform dissolution regime. A similar reactive core flood was conducted in the second rock which resulted in wormhole-like dissolution regime. We particularly examine the major image processing operations such as transformation of images to the same grey-scale, noise filtering and segmentation thresholding and propose quantitative methods to evaluate the effectiveness of these operations in voxel-wise analysis of successive images of a sample. In the second part, we generalize the methodology based on the three-phase segmentation of normalized images, microporosity assignment and 2D histogram of image intensities to estimate grey-scale changes of individual image voxels for a general case where the greyscale images are segmented into arbitrary number of phases. The results show that local (voxel

  5. SkyMine Carbon Mineralization Pilot Project

    SciTech Connect

    Christenson, Norm; Walters, Jerel

    2014-12-31

    This Topical Report addresses accomplishments achieved during Phase 2b of the SkyMine® Carbon Mineralization Pilot Project. The primary objectives of this project are to design, construct, and operate a system to capture CO2 from a slipstream of flue gas from a commercial coal-fired cement kiln, convert that CO2 to products having commercial value (i.e., beneficial use), show the economic viability of the CO2 capture and conversion process, and thereby advance the technology to the point of readiness for commercial scale demonstration and deployment. The overall process is carbon negative, resulting in mineralization of CO2 that would otherwise be released into the atmosphere. The project will also substantiate market opportunities for the technology by sales of chemicals into existing markets, and identify opportunities to improve technology performance and reduce costs at the commercial scale. The project is being conducted in two phases. The primary objectives of Phase 1 were to evaluate proven SkyMine® process chemistry for commercial pilot-scale operation and complete the preliminary design for the pilot plant to be built and operated in Phase 2, complete a NEPA evaluation, and develop a comprehensive carbon life cycle analysis. The objective of Phase 2b was to build the pilot plant to be operated and tested in Phase 2c.

  6. Carbon dioxide sequestration by direct mineral carbonation with carbonic acid

    SciTech Connect

    O'Connor, W.K.; Dahlin, D.C.; Nilsen, D.N.; Walters, R.P.; Turner, P.C.

    2000-07-01

    The Albany Research Center (ARC) of the US Department of Energy (DOE) has been conducting a series of mineral carbonation tests at its Albany, Oregon, facility over the past 2 years as part of a Mineral Carbonation Study Program within the DOE. The ARC tests have focused on ex-situ mineral carbonation in an aqueous system. The process developed at ARC utilizes a slurry of water mixed with a magnesium silicate mineral, olivine [forsterite and member (mg{sub 2}SiO{sub 4})], or serpentine [Mg{sub 3}Si{sub 2}O{sub 5}(OH){sub 4}]. This slurry is reacted with supercritical carbon dioxide (CO{sub 2}) to produce magnesite (MgCO{sub 3}). The CO{sub 2} is dissolved in water to form carbonic acid (H{sub 2}CO{sub 3}), which dissociates to H{sup +} and HCO{sub 3}{sup {minus}}. The H{sup +} reacts with the mineral, liberating Mg{sup 2+} cations which react with the bicarbonate to form the solid carbonate. The process is designed to simulate the natural serpentinization reaction of ultramafic minerals, and for this reason, these results may also be applicable to in-situ geological sequestration regimes. Results of the baseline tests, conducted on ground products of the natural minerals, have been encouraging. Tests conducted at ambient temperature (22 C) and subcritical CO{sub 2} pressures (below 73 atm) resulted in very slow conversion to the carbonate. However, when elevated temperatures and pressures are utilized, coupled with continuous stirring of the slurry and gas dispersion within the water column, significant reaction occurs within much shorter reaction times. Extent of reaction, as measured by the stoichiometric conversion of the silicate mineral (olivine) to the carbonate, is roughly 90% within 24 hours, using distilled water, and a reaction temperature of 185 C and a partial pressure of CO{sub 2} (P{sub CO{sub 2}}) of 115 atm. Recent tests using a bicarbonate solution, under identical reaction conditions, have achieved roughly 83% conversion of heat treated serpentine

  7. Carbon dioxide sequestration by direct mineral carbonation with carbonic acid

    SciTech Connect

    O'Connor, William K.; Dahlin, David C.; Nilsen, David N.; Walters, Richard P.; Turner, Paul C.

    2000-01-01

    The Albany Research Center (ARC) of the U.S. Dept. of Energy (DOE) has been conducting a series of mineral carbonation tests at its Albany, Oregon, facility over the past 2 years as part of a Mineral Carbonation Study Program within the DOE. Other participants in this Program include the Los Alamos National Laboratory, Arizona State University, Science Applications International Corporation, and the DOE National Energy Technology Laboratory. The ARC tests have focused on ex-situ mineral carbonation in an aqueous system. The process developed at ARC utilizes a slurry of water mixed with a magnesium silicate mineral, olivine [forsterite end member (Mg2SiO4)], or serpentine [Mg3Si2O5(OH)4]. This slurry is reacted with supercritical carbon dioxide (CO2) to produce magnesite (MgCO3). The CO2 is dissolved in water to form carbonic acid (H2CO3), which dissociates to H+ and HCO3 -. The H+ reacts with the mineral, liberating Mg2+ cations which react with the bicarbonate to form the solid carbonate. The process is designed to simulate the natural serpentinization reaction of ultramafic minerals, and for this reason, these results may also be applicable to in-situ geological sequestration regimes. Results of the baseline tests, conducted on ground products of the natural minerals, have been encouraging. Tests conducted at ambient temperature (22 C) and subcritical CO2 pressures (below 73 atm) resulted in very slow conversion to the carbonate. However, when elevated temperatures and pressures are utilized, coupled with continuous stirring of the slurry and gas dispersion within the water column, significant reaction occurs within much shorter reaction times. Extent of reaction, as measured by the stoichiometric conversion of the silicate mineral (olivine) to the carbonate, is roughly 90% within 24 hours, using distilled water, and a reaction temperature of 185?C and a partial pressure of CO2 (PCO2) of 115 atm. Recent tests using a bicarbonate solution, under identical reaction

  8. Mineralization of Carbon Dioxide: Literature Review

    SciTech Connect

    Romanov, V; Soong, Y; Carney, C; Rush, G; Nielsen, B; O'Connor, W

    2015-01-01

    CCS research has been focused on CO2 storage in geologic formations, with many potential risks. An alternative to conventional geologic storage is carbon mineralization, where CO2 is reacted with metal cations to form carbonate minerals. Mineralization methods can be broadly divided into two categories: in situ and ex situ. In situ mineralization, or mineral trapping, is a component of underground geologic sequestration, in which a portion of the injected CO2 reacts with alkaline rock present in the target formation to form solid carbonate species. In ex situ mineralization, the carbonation reaction occurs above ground, within a separate reactor or industrial process. This literature review is meant to provide an update on the current status of research on CO2 mineralization. 2

  9. Microbially mediated carbon mineralization: Geoengineering a carbon-neutral mine

    NASA Astrophysics Data System (ADS)

    Power, I. M.; McCutcheon, J.; Harrison, A. L.; Wilson, S. A.; Dipple, G. M.; Southam, G.

    2013-12-01

    Ultramafic and mafic mine tailings are a potentially valuable feedstock for carbon mineralization, affording the mining industry an opportunity to completely offset their carbon emissions. Passive carbon mineralization has previously been documented at the abandoned Clinton Creek asbestos mine, and the active Diavik diamond mine and Mount Keith nickel mine, yet the majority of tailings remain unreacted. Examples of microbe-carbonate interactions at each mine suggest that biological pathways could be harnessed to promote carbon mineralization. In suitable environmental conditions, microbes can mediate geochemical processes to accelerate mineral dissolution, increase the supply of carbon dioxide (CO2), and induce carbonate precipitation, all of which may accelerate carbon mineralization. Tailings mineralogy and the availability of a CO2 point source are key considerations in designing tailings storage facilities (TSF) for optimizing carbon mineralization. We evaluate the efficacy of acceleration strategies including bioleaching, biologically induced carbonate precipitation, and heterotrophic oxidation of waste organics, as well as abiotic strategies including enhancing passive carbonation through modifying tailings management practices and use of CO2 point sources (Fig. 1). With the aim of developing carbon-neutral mines, implementation of carbon mineralization strategies into TSF design will be driven by economic incentives and public pressure for environmental sustainability in the mining industry. Figure 1. Schematic illustrating geoengineered scenarios for carbon mineralization of ultramafic mine tailings. Scenarios A and B are based on non-point and point sources of CO2, respectively.

  10. Mapping the Mineral Resource Base for Mineral Carbon-Dioxide Sequestration in the Conterminous United States

    USGS Publications Warehouse

    Krevor, S.C.; Graves, C.R.; Van Gosen, B. S.; McCafferty, A.E.

    2009-01-01

    This database provides information on the occurrence of ultramafic rocks in the conterminous United States that are suitable for sequestering captured carbon dioxide in mineral form, also known as mineral carbon-dioxide sequestration. Mineral carbon-dioxide sequestration is a proposed greenhouse gas mitigation technology whereby carbon dioxide (CO2) is disposed of by reacting it with calcium or magnesium silicate minerals to form a solid magnesium or calcium carbonate product. The technology offers a large capacity to permanently store CO2 in an environmentally benign form via a process that takes little effort to verify or monitor after disposal. These characteristics are unique among its peers in greenhouse gas disposal technologies. The 2005 Intergovernmental Panel on Climate Change report on Carbon Dioxide Capture and Storage suggested that a major gap in mineral CO2 sequestration is locating the magnesium-silicate bedrock available to sequester the carbon dioxide. It is generally known that silicate minerals with high concentrations of magnesium are suitable for mineral carbonation. However, no assessment has been made in the United States that details their geographical distribution and extent, nor has anyone evaluated their potential for use in mineral carbonation. Researchers at Columbia University and the U.S. Geological Survey have developed a digital geologic database of ultramafic rocks in the conterminous United States. Data were compiled from varied-scale geologic maps of magnesium-silicate ultramafic rocks. The focus of our national-scale map is entirely on ultramafic rock types, which typically consist primarily of olivine- and serpentine-rich rocks. These rock types are potentially suitable as source material for mineral CO2 sequestration.

  11. Atom probe tomography (APT) of carbonate minerals.

    PubMed

    Pérez-Huerta, Alberto; Laiginhas, Fernando; Reinhard, David A; Prosa, Ty J; Martens, Rich L

    2016-01-01

    Atom probe tomography (APT) combines the highest spatial resolution with chemical data at atomic scale for the analysis of materials. For geological specimens, the process of field evaporation and molecular ion formation and interpretation is not yet entirely understood. The objective of this study is to determine the best conditions for the preparation and analysis by APT of carbonate minerals, of great importance in the interpretation of geological processes, focusing on the bulk chemical composition. Results show that the complexity of the mass spectrum is different for calcite and dolomite and relates to dissimilarities in crystalochemical parameters. In addition, APT bulk chemistry of calcite closely matches the expected stoichiometry but fails to provide accurate atomic percentages for elements in dolomite under the experimental conditions evaluated in this work. For both calcite and dolomite, APT underestimates the amount of oxygen based on their chemical formula, whereas it is able to detect small percentages of elemental substitutions in crystal lattices. Overall, our results demonstrate that APT of carbonate minerals is possible, but further optimization of the experimental parameters are required to improve the use of atom probe tomography for the correct interpretation of mineral geochemistry. PMID:26519815

  12. Atom probe tomography (APT) of carbonate minerals.

    PubMed

    Pérez-Huerta, Alberto; Laiginhas, Fernando; Reinhard, David A; Prosa, Ty J; Martens, Rich L

    2016-01-01

    Atom probe tomography (APT) combines the highest spatial resolution with chemical data at atomic scale for the analysis of materials. For geological specimens, the process of field evaporation and molecular ion formation and interpretation is not yet entirely understood. The objective of this study is to determine the best conditions for the preparation and analysis by APT of carbonate minerals, of great importance in the interpretation of geological processes, focusing on the bulk chemical composition. Results show that the complexity of the mass spectrum is different for calcite and dolomite and relates to dissimilarities in crystalochemical parameters. In addition, APT bulk chemistry of calcite closely matches the expected stoichiometry but fails to provide accurate atomic percentages for elements in dolomite under the experimental conditions evaluated in this work. For both calcite and dolomite, APT underestimates the amount of oxygen based on their chemical formula, whereas it is able to detect small percentages of elemental substitutions in crystal lattices. Overall, our results demonstrate that APT of carbonate minerals is possible, but further optimization of the experimental parameters are required to improve the use of atom probe tomography for the correct interpretation of mineral geochemistry.

  13. A NOVEL APPROACH TO MINERAL CARBONATION: ENHANCING CARBONATION WHILE AVOIDING MINERAL PRETREATMENT PROCESS COST

    SciTech Connect

    Michael J. McKelvy; Andrew V.G. Chizmeshya; Kyle Squires; Ray W. Carpenter; Hamadallah Bearat

    2005-10-01

    Known fossil fuel reserves, especially coal, can support global energy demands for centuries to come, if the environmental problems associated with CO{sub 2} emissions can be overcome. Unlike other CO{sub 2} sequestration candidate technologies that propose long-term storage, mineral sequestration provides permanent disposal by forming geologically stable mineral carbonates. Carbonation of the widely occurring mineral olivine (e.g., forsterite, Mg{sub 2}SiO{sub 4}) is a large-scale sequestration process candidate for regional implementation, which converts CO{sub 2} into the environmentally benign mineral magnesite (MgCO{sub 3}). The primary goal is cost-competitive process development. As the process is exothermic, it inherently offers low-cost potential. Enhancing carbonation reactivity is key to economic viability. Recent studies at the U.S. DOE Albany Research Center have established that aqueous-solution carbonation using supercritical CO{sub 2} is a promising process; even without olivine activation, 30-50% carbonation has been achieved in an hour. Mechanical activation (e.g., attrition) has accelerated the carbonation process to an industrial timescale (i.e., near completion in less than an hour), at reduced pressure and temperature. However, the activation cost is too high to be economical and lower cost pretreatment options are needed. Herein, we report our first year progress in exploring a novel approach that offers the potential to substantially enhance carbonation reactivity while bypassing pretreatment activation. We have discovered that robust silica-rich passivating layers form on the olivine surface during carbonation. As carbonation proceeds, these passivating layers thicken, fracture and eventually exfoliate, exposing fresh olivine surfaces during rapidly-stirred/circulating carbonation. We are exploring the mechanisms that govern carbonation reactivity and the impact that (1) modeling/controlling the slurry fluid-flow conditions, (2) varying the

  14. Mineralization strategies for carbon dioxide sequestration

    SciTech Connect

    Penner, Larry R.; O'Connor, William K.; Gerdemann, Stephen J.; Dahlin, David C.

    2003-01-01

    Progress is reported in three primary research areas--each concerned with sequestering carbon dioxide into mineral matrices. Direct mineral carbonation was pioneered at Albany Research Center. The method treats the reactant, olivine or serpentine in aqueous media with carbon dioxide at high temperature and pressure to form stable mineral carbonates. Recent results are introduced for pretreatment by high-intensity grinding to improve carbonation efficiency. To prove feasibility of the carbonation process, a new reactor was designed and operated to progress from batch tests to continuous operation. The new reactor is a prototype high-temperature, high-pressure flow loop reactor that will furnish information on flow, energy consumption, and wear and corrosion resulting from slurry flow and the carbonation reaction. A promising alternative mineralization approach is also described. New data are presented for long-term exposure of carbon dioxide to Colombia River Basalt to determine the extent of conversion of carbon dioxide to permanent mineral carbonates. Batch autoclave tests were conducted using drill-core samples of basalt and reacted under conditions that simulate in situ injection into basalt-containing geological formations.

  15. Multiphase Sequestration Geochemistry: Model for Mineral Carbonation

    SciTech Connect

    White, Mark D.; McGrail, B. Peter; Schaef, Herbert T.; Hu, Jian Z.; Hoyt, David W.; Felmy, Andrew R.; Rosso, Kevin M.; Wurstner, Signe K.

    2011-04-01

    Carbonation of formation minerals converts low viscosity supercritical CO2 injected into deep saline reservoirs for geologic sequestration into an immobile form. Until recently the scientific focus of mineralization reactions with reservoir rocks has been those that follow an aqueous-mediated dissolution/precipitation mechanism, driven by the sharp reduction in pH that occurs with CO2 partitioning into the aqueous phase. For sedimentary basin formations the kinetics of aqueous-mediated dissolution/precipitation reactions are sufficiently slow to make the role of mineralization trapping insignificant over a century period. For basaltic saline formations aqueous-phase mineralization progresses at a substantially higher rate, making the role of mineralization trapping significant, if not dominant, over a century period. The overlooked mineralization reactions for both sedimentary and basaltic saline formations, however, are those that occur in liquid or supercritical CO2 phase; where, dissolved water appears to play a catalyst role in the formation of carbonate minerals. A model is proposed in this paper that describes mineral carbonation over sequestration reservoir conditions ranging from dissolved CO2 in aqueous brine to dissolved water in supercritical CO2. The model theory is based on a review of recent experiments directed at understanding the role of water in mineral carbonation reactions of interest in geologic sequestration systems occurring under low water contents.

  16. SkyMine Carbon Mineralization Pilot Project

    SciTech Connect

    Joe Jones; Clive Barton; Mark Clayton; Al Yablonsky; David Legere

    2010-09-30

    This Topical Report addresses accomplishments achieved during Phase 1 of the SkyMine{reg_sign} Carbon Mineralization Pilot Project. The primary objectives of this project are to design, construct, and operate a system to capture CO{sub 2} from a slipstream of flue gas from a commercial coal-fired cement kiln, convert that CO{sub 2} to products having commercial value (i.e., beneficial use), show the economic viability of the CO{sub 2} capture and conversion process, and thereby advance the technology to a point of readiness for commercial scale demonstration and proliferation. The project will also substantiate market opportunities for the technology by sales of chemicals into existing markets, and identify opportunities to improve technology performance and reduce costs at commercial scale. The primary objectives of Phase 1 of the project were to elaborate proven SkyMine{reg_sign} process chemistry to commercial pilot-scale operation and complete the preliminary design ('Reference Plant Design') for the pilot plant to be built and operated in Phase 2. Additionally, during Phase 1, information necessary to inform a DOE determination regarding NEPA requirements for the project was developed, and a comprehensive carbon lifecycle analysis was completed. These items were included in the formal application for funding under Phase 2. All Phase 1 objectives were successfully met on schedule and within budget.

  17. A Novel Approach To Mineral Carbonation: Enhancing Carbonation While Avoiding Mineral Pretreatment Process Cost

    SciTech Connect

    Michael J. McKelvy; Andrew V. G. Chizmeshya; Kyle Squires; Ray W. Carpenter; Hamdallah Bearat

    2006-06-21

    Known fossil fuel reserves, especially coal, can support global energy demands for centuries to come, if the environmental problems associated with CO{sub 2} emissions can be overcome. Unlike other CO{sub 2} sequestration candidate technologies that propose long-term storage, mineral sequestration provides permanent disposal by forming geologically stable mineral carbonates. Carbonation of the widely occurring mineral olivine (e.g., forsterite, Mg{sub 2}SiO{sub 4}) is a large-scale sequestration process candidate for regional implementation, which converts CO{sub 2} into the environmentally benign mineral magnesite (MgCO{sub 3}). The primary goal is cost-competitive process development. As the process is exothermic, it inherently offers low-cost potential. Enhancing carbonation reactivity is key to economic viability. Recent studies at the U.S. DOE Albany Research Center have established that aqueous-solution carbonation using supercritical CO{sub 2} is a promising process; even without olivine activation, 30-50% carbonation has been achieved in an hour. Mechanical activation (e.g., attrition) has accelerated the carbonation process to an industrial timescale (i.e., near completion in less than an hour), at reduced pressure and temperature. However, the activation cost is too high to be economical and lower cost pretreatment options are needed. Herein, we report our second year progress in exploring a novel approach that offers the potential to substantially enhance carbonation reactivity while bypassing pretreatment activation. As our second year progress is intimately related to our earlier work, the report is presented in that context to provide better overall understanding of the progress made. We have discovered that robust silica-rich passivating layers form on the olivine surface during carbonation. As carbonation proceeds, these passivating layers thicken, fracture and eventually exfoliate, exposing fresh olivine surfaces during rapidly

  18. Impacts of Nickel Nanoparticles on Mineral Carbonation

    PubMed Central

    Bodor, Marius; Santos, Rafael M.; Chiang, Yi Wai; Vlad, Maria; Van Gerven, Tom

    2014-01-01

    This work presents experimental results regarding the use of pure nickel nanoparticles (NiNP) as a mineral carbonation additive. The aim was to confirm if the catalytic effect of NiNP, which has been reported to increase the dissolution of CO2 and the dissociation of carbonic acid in water, is capable of accelerating mineral carbonation processes. The impacts of NiNP on the CO2 mineralization by four alkaline materials (pure CaO and MgO, and AOD and CC steelmaking slags), on the product mineralogy, on the particle size distribution, and on the morphology of resulting materials were investigated. NiNP-containing solution was found to reach more acidic pH values upon CO2 bubbling, confirming a higher quantity of bicarbonate ions. This effect resulted in acceleration of mineral carbonation in the first fifteen minutes of reaction time when NiNP was present. After this initial stage, however, no benefit of NiNP addition was seen, resulting in very similar carbonation extents after one hour of reaction time. It was also found that increasing solids content decreased the benefit of NiNP, even in the early stages. These results suggest that NiNP has little contribution to mineral carbonation processes when the dissolution of alkaline earth metals is rate limiting. PMID:24578669

  19. Impacts of nickel nanoparticles on mineral carbonation.

    PubMed

    Bodor, Marius; Santos, Rafael M; Chiang, Yi Wai; Vlad, Maria; Van Gerven, Tom

    2014-01-01

    This work presents experimental results regarding the use of pure nickel nanoparticles (NiNP) as a mineral carbonation additive. The aim was to confirm if the catalytic effect of NiNP, which has been reported to increase the dissolution of CO₂ and the dissociation of carbonic acid in water, is capable of accelerating mineral carbonation processes. The impacts of NiNP on the CO₂ mineralization by four alkaline materials (pure CaO and MgO, and AOD and CC steelmaking slags), on the product mineralogy, on the particle size distribution, and on the morphology of resulting materials were investigated. NiNP-containing solution was found to reach more acidic pH values upon CO₂ bubbling, confirming a higher quantity of bicarbonate ions. This effect resulted in acceleration of mineral carbonation in the first fifteen minutes of reaction time when NiNP was present. After this initial stage, however, no benefit of NiNP addition was seen, resulting in very similar carbonation extents after one hour of reaction time. It was also found that increasing solids content decreased the benefit of NiNP, even in the early stages. These results suggest that NiNP has little contribution to mineral carbonation processes when the dissolution of alkaline earth metals is rate limiting.

  20. Carbon K-edge Spectra of Carbonate Minerals

    SciTech Connect

    Brandes, J.; Wirick, S; Jacobsen, C

    2010-01-01

    Carbon K-edge X-ray spectroscopy has been applied to the study of a wide range of organic samples, from polymers and coals to interstellar dust particles. Identification of carbonaceous materials within these samples is accomplished by the pattern of resonances in the 280-320 eV energy region. Carbonate minerals are often encountered in the study of natural samples, and have been identified by a distinctive resonance at 290.3 eV. Here C K-edge and Ca L-edge spectra from a range of carbonate minerals are presented. Although all carbonates exhibit a sharp 290 eV resonance, both the precise position of this resonance and the positions of other resonances vary among minerals. The relative strengths of the different carbonate resonances also vary with crystal orientation to the linearly polarized X-ray beam. Intriguingly, several carbonate minerals also exhibit a strong 288.6 eV resonance, consistent with the position of a carbonyl resonance rather than carbonate. Calcite and aragonite, although indistinguishable spectrally at the C K-edge, exhibited significantly different spectra at the Ca L-edge. The distinctive spectral fingerprints of carbonates provide an identification tool, allowing for the examination of such processes as carbon sequestration in minerals, Mn substitution in marine calcium carbonates (dolomitization) and serpentinization of basalts.

  1. Applications of mineral carbonation to geological sequestration of CO2

    SciTech Connect

    O'Connor, William K.; Rush, G.E.

    2005-01-01

    Geological sequestration of CO2 is a promising near-term sequestration methodology. However, migration of the CO2 beyond the natural reservoir seals could become problematic, thus the identification of means to enhance the natural seals could prove beneficial. Injection of a mineral reactant slurry could provide a means to enhance the natural reservoir seals by supplying the necessary cations for precipitation of mineral carbonates. The subject study evaluates the merit of several mineral slurry injection strategies by conduct of a series of laboratory-scale CO2 flood tests on whole core samples of the Mt. Simon sandstone from the Illinois Basin.

  2. [Organic carbon and carbon mineralization characteristics in nature forestry soil].

    PubMed

    Yang, Tian; Dai, Wei; An, Xiao-Juan; Pang, Huan; Zou, Jian-Mei; Zhang, Rui

    2014-03-01

    Through field investigation and indoor analysis, the organic carbon content and organic carbon mineralization characteristics of six kinds of natural forest soil were studied, including the pine forests, evergreen broad-leaved forest, deciduous broad-leaved forest, mixed needle leaf and Korean pine and Chinese pine forest. The results showed that the organic carbon content in the forest soil showed trends of gradual decrease with the increase of soil depth; Double exponential equation fitted well with the organic carbon mineralization process in natural forest soil, accurately reflecting the mineralization reaction characteristics of the natural forest soil. Natural forest soil in each layer had the same mineralization reaction trend, but different intensity. Among them, the reaction intensity in the 0-10 cm soil of the Korean pine forest was the highest, and the intensities of mineralization reaction in its lower layers were also significantly higher than those in the same layers of other natural forest soil; comparison of soil mineralization characteristics of the deciduous broad-leaved forest and coniferous and broad-leaved mixed forest found that the differences of litter species had a relatively strong impact on the active organic carbon content in soil, leading to different characteristics of mineralization reaction.

  3. A Novel Approach to Mineral Carbonation: Enhancing Carbonation While Avoiding Mineral Pretreatment Process Cost

    SciTech Connect

    Andrew V. G. Chizmeshya; Michael J. McKelvy; Kyle Squires; Ray W. Carpenter; Hamdallah Bearat

    2007-06-21

    Known fossil fuel reserves, especially coal, can support global energy demands for centuries to come, if the environmental problems associated with CO{sub 2} emissions can be overcome. Unlike other CO{sub 2} sequestration candidate technologies that propose long-term storage, mineral sequestration provides permanent disposal by forming geologically stable mineral carbonates. Carbonation of the widely occurring mineral olivine (e.g., forsterite, Mg{sub 2}SiO{sub 4}) is a large-scale sequestration process candidate for regional implementation, which converts CO{sub 2} into the environmentally benign mineral magnesite (MgCO{sub 3}). The primary goal is cost-competitive process development. As the process is exothermic, it inherently offers low-cost potential. Enhancing carbonation reactivity is key to economic viability. Recent studies at the U.S. DOE Albany Research Center have established that aqueous-solution carbonation using supercritical CO{sub 2} is a promising process; even without olivine activation, 30-50% carbonation has been achieved in an hour. Mechanical activation (e.g., attrition) has accelerated the carbonation process to an industrial timescale (i.e., near completion in less than an hour), at reduced pressure and temperature. However, the activation cost is too high to be economical and lower cost pretreatment options are needed. We have discovered that robust silica-rich passivating layers form on the olivine surface during carbonation. As carbonation proceeds, these passivating layers thicken, fracture and eventually exfoliate, exposing fresh olivine surfaces during rapidly-stirred/circulating carbonation. We are exploring the mechanisms that govern carbonation reactivity and the impact that (1) modeling/controlling the slurry fluid-flow conditions, (2) varying the aqueous ion species/size and concentration (e.g., Li+, Na+, K+, Rb+, Cl-, HCO{sub 3}{sup -}), and (3) incorporating select sonication offer to enhance exfoliation and carbonation. Thus

  4. Simulating the Mineral Scale by High Pressure Thermal Vessel

    NASA Astrophysics Data System (ADS)

    Huang, Y. H.; Liu, H. L.; Chen, H. F.; Song, S. R.

    2014-12-01

    The generating capacity of Chingshui geothermal power plant decreased rapidly after it had operated three years. Chinese Petroleum Corporation (CPC) attributed the main reason was the depletion of reservoir. One reason was that the reservoir did not be recharged. And the other was the mineral scale in reservoir and pipes which caused flow rate decreased. There are abundant geothermal energy in Taiwan. But in Chingshui, the spring has amount content of carbonate. Most scaling are calcium carbonate and silica. These two materials have different solubility in various pH and physical conditions. Because the pressure reduced in the process of upwelling, the hot spring from the reservoir deposited calcium carbonate immediately by large carbon dioxide escape. This result caused the diameter of pipeline reduced. Besides, as the temperature decreased, the silica would scaling in the part of heat exchanger. To avoid the failure experience in Chingshui , how to prevent the mineral scaling is the key point that we need to solve. Our study will use hydrothermal experiments by High Pressure Thermal Vessel to simulate the process of spring water upwelling from reservoir to surface, to understand whether calcium carbonate and silica scaling or not in different temperature and pressure. This study choose the Hongchailin well as objects to simulate, and the target layers of drilling well were set as Szeleng sandstone and Lushan slate. We used pure water and saturated water pressure in our experiments. There were four vessels in High thermal vessel. The first vessel was used to simulate the condition of reservoir. The second and third vessel were simulated the conditions in the well when spring water upwelling to the surface. And the last vessel was simulated the conditions on surface surroundings. We hope to get the temperature and pressure when the scaling occurred, and verified with the computing result, thus we can inhibit the scaling.

  5. Mineral Carbonation Employing Ultramafic Mine Waste

    NASA Astrophysics Data System (ADS)

    Southam, G.; McCutcheon, J.; Power, I. M.; Harrison, A. L.; Wilson, S. A.; Dipple, G. M.

    2014-12-01

    Carbonate minerals are an important, stable carbon sink being investigated as a strategy to sequester CO2 produced by human activity. A natural playa (Atlin, BC, CAN) that has demonstrated the ability to microbially-accelerate hydromagnesite formation was used as an experimental model. Growth of microbial mats from Atlin, in a 10 m long flow-through bioreactor catalysed hydromagnesite precipitation under 'natural' conditions. To enhance mineral carbonation, chrysotile from the Clinton Creek Asbestos Mine (YT, CAN) was used as a target substrate for sulphuric acid leaching, releasing as much as 94% of the magnesium into solution via chemical weathering. This magnesium-rich 'feedstock' was used to examine the ability of the microbialites to enhance carbonate mineral precipitation using only atmospheric CO2 as the carbon source. The phototrophic consortium catalysed the precipitation of platy hydromagnesite [Mg5(CO3)4(OH)2·4H2O] accompanied by magnesite [MgCO3], aragonite [CaCO3], and minor dypingite [Mg5(CO3)4(OH)2·5H2O]. Scanning Electron Microscopy-Energy Dispersive Spectroscopy indicated that cell exteriors and extracellular polymeric substances (EPS) served as nucleation sites for carbonate precipitation. In many cases, entire cyanobacteria filaments were entombed in magnesium carbonate coatings, which appeared to contain a framework of EPS. Cell coatings were composed of small crystals, which intuitively resulted from rapid crystal nucleation. Excess nutrient addition generated eutrophic conditions in the bioreactor, resulting in the growth of a pellicle that sealed the bioreactor contents from the atmosphere. The resulting anaerobic conditions induced fermentation and subsequent acid generation, which in turn caused a drop in pH to circumneutral values and a reduction in carbonate precipitation. Monitoring of the water chemistry conditions indicated that a high pH (> 9.4), and relatively high concentrations of magnesium (> 3000 ppm), compared with the natural

  6. Carbon dioxide sequestration by aqueous mineral carbonation of magnesium silicate minerals

    SciTech Connect

    Gerdemann, Stephen J.; Dahlin, David C.; O'Connor, William K.; Penner, Larry R.

    2003-01-01

    The dramatic increase in atmospheric carbon dioxide since the Industrial Revolution has caused concerns about global warming. Fossil-fuel-fired power plants contribute approximately one third of the total human-caused emissions of carbon dioxide. Increased efficiency of these power plants will have a large impact on carbon dioxide emissions, but additional measures will be needed to slow or stop the projected increase in the concentration of atmospheric carbon dioxide. By accelerating the naturally occurring carbonation of magnesium silicate minerals it is possible to sequester carbon dioxide in the geologically stable mineral magnesite (MgCO3). The carbonation of two classes of magnesium silicate minerals, olivine (Mg2SiO4) and serpentine (Mg3Si2O5(OH)4), was investigated in an aqueous process. The slow natural geologic process that converts both of these minerals to magnesite can be accelerated by increasing the surface area, increasing the activity of carbon dioxide in the solution, introducing imperfections into the crystal lattice by high-energy attrition grinding, and in the case of serpentine, by thermally activating the mineral by removing the chemically bound water. The effect of temperature is complex because it affects both the solubility of carbon dioxide and the rate of mineral dissolution in opposing fashions. Thus an optimum temperature for carbonation of olivine is approximately 185 degrees C and 155 degrees C for serpentine. This paper will elucidate the interaction of these variables and use kinetic studies to propose a process for the sequestration of the carbon dioxide.

  7. Novel biological approaches to carbon mineralization

    NASA Astrophysics Data System (ADS)

    Power, Ian; Kenward, Paul; Harrison, Anna; Dipple, Gregory; Raudsepp, Mati; Wilson, Siobhan; Southam, Gordon

    2015-04-01

    Innovative approaches for accelerating and manipulating fundamental geochemical processes are necessary to develop carbon mineralization as a viable strategy for the mitigation of greenhouse gas emissions. Mg-carbonate formation is of interest for both ex situ and in situ CO2 sequestration strategies1. Accordingly, we have investigated approaches to accelerate these water-rock reactions that produce Mg-carbonate minerals using biological approaches. For instance, CO2-limited conditions are encountered in many systems relevant to CO2 sequestration and represent a severe limitation on carbon mineralization. In carbonation experiments, the supply of CO2 was increased with the use of carbonic anhydrase, an enzyme that catalyzes the hydration of aqueous CO2. The presence of carbonic anhydrase had a dramatic impact on carbonation rates of brucite [Mg(OH)2]2, a mineral of interest for carbon sequestration3. In a CO2-rich aqueous environment, cyanobacteria were able to induce hydrated Mg-carbonate precipitation in microcosm experiments through the alkalinization of their microenvironment and concentration of cations on their cell membranes, which also provide regularly spaced, chemically identical sites for mineral nucleation4. In both lines of investigation, the resulting precipitates were metastable hydrated Mg-carbonate minerals rather then magnesite [MgCO3], the most stable Mg-carbonate and therefore the preferred product forsequestering CO2. Consequently, we have investigated approaches to improve magnesite precipitation rate in these low temperature environments. Inopportunely, rates of magnesite precipitation are severely limited at temperatures below 60 ° C due to the strong hydration of Mg2+ ions in solution5. Yet, carboxyl functional groups (R-COOH) are able to cause desolvation of Mg2+ ions6,7. In microcosm experiments using polystyrene microspheres with a high density of carboxyl groups, we were able to precipitate magnesite at room temperature from slightly

  8. Mineral dissolution kinetics at the pore scale

    SciTech Connect

    Li, L.; Steefel, C.I.; Yang, L.

    2007-05-24

    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

  9. Carbon dioxide sequestration in cement kiln dust through mineral carbonation

    SciTech Connect

    Deborah N. Huntzinger; John S. Gierke; S. Komar Kawatra; Timothy C. Eisele; Lawrence L. Sutter

    2009-03-15

    Carbon sequestration through the formation of carbonates is a potential means to reduce CO{sub 2} emissions. Alkaline industrial solid wastes typically have high mass fractions of reactive oxides that may not require preprocessing, making them an attractive source material for mineral carbonation. The degree of mineral carbonation achievable in cement kiln dust (CKD) under ambient temperatures and pressures was examined through a series of batch and column experiments. The overall extent and potential mechanisms and rate behavior of the carbonation process were assessed through a complementary set of analytical and empirical methods, including mass change, thermal analysis, and X-ray diffraction. The carbonation reactions were carried out primarily through the reaction of CO{sub 2} with Ca(OH){sub 2}, and CaCO{sub 3} was observed as the predominant carbonation product. A sequestration extent of over 60% was observed within 8 h of reaction without any modifications to the waste. Sequestration appears to follow unreacted core model theory where reaction kinetics are controlled by a first-order rate constant at early times; however, as carbonation progresses, the kinetics of the reaction are attenuated by the extent of the reaction due to diffusion control, with the extent of conversion never reaching completion. 35 refs., 3 figs., 1 tab.

  10. Carbon dioxide sequestration in cement kiln dust through mineral carbonation.

    PubMed

    Huntzinger, Deborah N; Gierke, John S; Kawatra, S Komar; Eisele, Timothy C; Sutter, Lawrence L

    2009-03-15

    Carbon sequestration through the formation of carbonates is a potential means to reduce CO2 emissions. Alkaline industrial solid wastes typically have high mass fractions of reactive oxides that may not require preprocessing, making them an attractive source material for mineral carbonation The degree of mineral carbonation achievable in cement kiln dust (CKD) underambienttemperatures and pressures was examined through a series of batch and column experiments. The overall extent and potential mechanisms and rate behavior of the carbonation process were assessed through a complementary set of analytical and empirical methods, including mass change, thermal analysis, and X-ray diffraction. The carbonation reactions were carried out primarily through the reaction of CO2 with Ca(OH)2, and CaCO3 was observed as the predominant carbonation product. A sequestration extent of over 60% was observed within 8 h of reaction without any modifications to the waste. Sequestration appears to follow unreacted core model theory where reaction kinetics are controlled by a first-order rate constant at early times; however, as carbonation progresses, the kinetics of the reaction are attenuated by the extent of the reaction due to diffusion control, with the extent of conversion never reaching completion.

  11. Carbon dioxide sequestration in cement kiln dust through mineral carbonation.

    PubMed

    Huntzinger, Deborah N; Gierke, John S; Kawatra, S Komar; Eisele, Timothy C; Sutter, Lawrence L

    2009-03-15

    Carbon sequestration through the formation of carbonates is a potential means to reduce CO2 emissions. Alkaline industrial solid wastes typically have high mass fractions of reactive oxides that may not require preprocessing, making them an attractive source material for mineral carbonation The degree of mineral carbonation achievable in cement kiln dust (CKD) underambienttemperatures and pressures was examined through a series of batch and column experiments. The overall extent and potential mechanisms and rate behavior of the carbonation process were assessed through a complementary set of analytical and empirical methods, including mass change, thermal analysis, and X-ray diffraction. The carbonation reactions were carried out primarily through the reaction of CO2 with Ca(OH)2, and CaCO3 was observed as the predominant carbonation product. A sequestration extent of over 60% was observed within 8 h of reaction without any modifications to the waste. Sequestration appears to follow unreacted core model theory where reaction kinetics are controlled by a first-order rate constant at early times; however, as carbonation progresses, the kinetics of the reaction are attenuated by the extent of the reaction due to diffusion control, with the extent of conversion never reaching completion. PMID:19368202

  12. Nitrogen Mineralization and Assimilation at Millimeter Scales

    SciTech Connect

    Cliff, John B.; Bottomley, Peter J.; Gaspar, Dan J.; Myrold, David D.

    2006-11-15

    This study used inoculated, artificial soil microcosms containing sand, clay, cellulose, and localized hotspots of highly labile, organic-N containing dead bacteria to study N mineralization and assimilation at submillimeter and centimeter scales. Labeling with 15NH4+ along with measurement of label assimilated into microbial biomass at the bulk scale allowed estimation of gross rates of ammonification and N assimilation using isotope dilution. Time-of-flight secondary ion mass spectrometry (ToF-SIMS) analyses of transects of organic-15N across Si wafers in contact with the microcosms indicated strong gradients of 15NH4+ assimilation as a function of proximity to the hotspots that were not apparent using bulk analyses. This combination of bulk and ToF-SIMS analyses represents a powerful approach to explore the physical and biochemical factors that affect N process heterogeneities in soils.

  13. Relationship between carbon and nitrogen mineralization in a subtropical soil

    NASA Astrophysics Data System (ADS)

    Li, Qianru; Sun, Yue; Zhang, Xinyu; Xu, Xingliang; Kuzyakov, Yakov

    2014-05-01

    In most soils, more than 90% nitrogen is bonded with carbon in organic forms. This indicates that carbon mineralization should be closely coupled with nitrogen mineralization, showing a positive correlation between carbon and nitrogen mineralization. To test this hypothesis above, we conducted an incubation using a subtropical soil for 10 days at 15 °C and 25 °C. 13C-labeled glucose and 15N-labeled ammonium or nitrate was used to separate CO2 and mineral N released from mineralization of soil organic matter and added glucose or inorganic nitrogen. Phospholipid fatty acid (PLFA) and four exoenzymes (i.e. β-1,4- Glucosaminidase, chitinase, acid phosphatase, β-1,4-N- acetyl glucosamine glycosidase) were also analyzed to detect change in microbial activities during the incubation. Our results showed that CO2 release decreased with increasing nitrogen mineralization rates. Temperature did not change this relationship between carbon and nitrogen mineralization. Although some changes in PLFA and the four exoenzymes were observed, these changes did not contribute to changes in carbon and nitrogen mineralization. These findings indicates that carbon and nitrogen mineralization in soil are more complicated than as previously expected. Future investigation should focus on why carbon and nitrogen mineralization are coupled in a negative correlation not in a positive correlation in many soils for a better understanding of carbon and nitrogen transformation during their mineralization.

  14. CARBON DIOXIDE SEQUESTRATION BY MECHANOCHEMICAL CARBONATION OF MINERAL SILICATES

    SciTech Connect

    Michael G. Nelson

    2004-04-01

    The University of Utah and the University of Idaho investigated the carbonation of silicate minerals by mechanochemical processing. This method uses intense grinding, and has the potential of being much less expensive than other methods of mineral sequestration. Tests were conducted in three types of grinding devices. In these tests, natural and synthetic silicate compounds were ground for varying times in the presence of gaseous CO{sub 2}. A significant change takes place in the lizardite variety of serpentine after 15 to 20 minutes of intense grinding in the presence of gaseous CO{sub 2}. The X-ray diffraction spectrum of lizardite thus treated was much different than that of the untreated mineral. This spectrum could not be identified as that of any natural or synthetic material. Laboratory analyses showed that small amounts of carbon are fixed by grinding lizardite, forsterite, and wollastonite (all naturally-occurring minerals), and synthetic magnesium silicate, in the presence of gaseous CO{sub 2}. It was thus concluded that further investigation was warranted, and a follow-up proposal was submitted to the Department of Energy under solicitation number.

  15. Integrating Steel Production with Mineral Carbon Sequestration

    SciTech Connect

    Klaus Lackner; Paul Doby; Tuncel Yegulalp; Samuel Krevor; Christopher Graves

    2008-05-01

    The objectives of the project were (i) to develop a combination iron oxide production and carbon sequestration plant that will use serpentine ores as the source of iron and the extraction tailings as the storage element for CO2 disposal, (ii) the identification of locations within the US where this process may be implemented and (iii) to create a standardized process to characterize the serpentine deposits in terms of carbon disposal capacity and iron and steel production capacity. The first objective was not accomplished. The research failed to identify a technique to accelerate direct aqueous mineral carbonation, the limiting step in the integration of steel production and carbon sequestration. Objective (ii) was accomplished. It was found that the sequestration potential of the ultramafic resource surfaces in the US and Puerto Rico is approximately 4,647 Gt of CO2 or over 500 years of current US production of CO2. Lastly, a computer model was developed to investigate the impact of various system parameters (recoveries and efficiencies and capacities of different system components) and serpentinite quality as well as incorporation of CO2 from sources outside the steel industry.

  16. Delineation of Magnesium-rich Ultramafic Rocks Available for Mineral Carbon Sequestration in the United States

    USGS Publications Warehouse

    Krevor, S.C.; Graves, C.R.; Van Gosen, B. S.; McCafferty, A.E.

    2009-01-01

    The 2005 Intergovernmental Panel on Climate Change report on Carbon Dioxide Capture and Storage suggested that a major gap in mineral carbon sequestration is locating the magnesium-silicate bedrock available to sequester CO2. It is generally known that silicate minerals with high concentrations of magnesium are suitable for mineral carbonation. However, no assessment has been made covering the entire United States detailing their geographical distribution and extent, or evaluating their potential for use in mineral carbonation. Researchers at Columbia University and the U.S. Geological Survey have developed a digital geologic database of ultramafic rocks in the continental United States. Data were compiled from varied-scale geologic maps of magnesium-silicate ultramafic rocks. These rock types are potentially suitable as source material for mineral carbon-dioxide sequestration. The focus of the national-scale map is entirely on suitable ultramafic rock types, which typically consist primarily of olivine and serpentine minerals. By combining the map with digital datasets that show non-mineable lands (such as urban areas and National Parks), estimates on potential depth of a surface mine, and the predicted reactivities of the mineral deposits, one can begin to estimate the capacity for CO2 mineral sequestration within the United States. ?? 2009 Elsevier Ltd. All rights reserved.

  17. Energy and economic considerations for ex-situ and aqueous mineral carbonation

    SciTech Connect

    O'Connor, William K.; Dahlin, David C.; Rush, G.E.; Gerdemann, Stephen J.; Penner, L.R.

    2004-01-01

    Due to the scale and breadth of carbon dioxide emissions, and speculation regarding their impact on global climate, sequestration of some portion of these emissions has been under increased study. A practical approach to carbon sequestration will likely include several options, which will be driven largely by the energy demand and economics of operation. Aqueous mineral carbonation of calcium and magnesium silicate minerals has been studied as one potential method to sequester carbon dioxide. Although these carbonation reactions are all thermodynamically favored, they occur at geologic rates of reaction. Laboratory studies have demonstrated that these rates of reaction are accelerated with increasing temperature, pressure, and particle surface area. Mineral-specific activation methods were identified, however, each of these techniques incurs energy as well as economic costs. An overview of the mineral availability, pretreatment options and energy demands, and process economics is provided.

  18. Mineral protection of soil carbon counteracted by root exudates

    NASA Astrophysics Data System (ADS)

    Keiluweit, Marco; Bougoure, Jeremy J.; Nico, Peter S.; Pett-Ridge, Jennifer; Weber, Peter K.; Kleber, Markus

    2015-06-01

    Multiple lines of existing evidence suggest that climate change enhances root exudation of organic compounds into soils. Recent experimental studies show that increased exudate inputs may cause a net loss of soil carbon. This stimulation of microbial carbon mineralization (`priming’) is commonly rationalized by the assumption that exudates provide a readily bioavailable supply of energy for the decomposition of native soil carbon (co-metabolism). Here we show that an alternate mechanism can cause carbon loss of equal or greater magnitude. We find that a common root exudate, oxalic acid, promotes carbon loss by liberating organic compounds from protective associations with minerals. By enhancing microbial access to previously mineral-protected compounds, this indirect mechanism accelerated carbon loss more than simply increasing the supply of energetically more favourable substrates. Our results provide insights into the coupled biotic-abiotic mechanisms underlying the `priming’ phenomenon and challenge the assumption that mineral-associated carbon is protected from microbial cycling over millennial timescales.

  19. Mars Life? - Orange-colored Carbonate Mineral Globules

    NASA Technical Reports Server (NTRS)

    1996-01-01

    This photograph shows orange-colored carbonate mineral globules found in a meteorite, called ALH84001, believed to have once been a part of Mars. These carbonate minerals in the meteorite are believed to have been formed on Mars more than 3.6 billion years ago. Their structure and chemistry suggest that they may have been formed with the assistance of primitive, bacteria-like living organisms. A two-year investigation by a NASA research team found organic molecules, mineral features characteristic of biological activity and possible microscopic fossils inside of carbonate minerals such as these in the meteorite.

  20. Soil organic carbon across scales.

    PubMed

    O'Rourke, Sharon M; Angers, Denis A; Holden, Nicholas M; McBratney, Alex B

    2015-10-01

    Mechanistic understanding of scale effects is important for interpreting the processes that control the global carbon cycle. Greater attention should be given to scale in soil organic carbon (SOC) science so that we can devise better policy to protect/enhance existing SOC stocks and ensure sustainable use of soils. Global issues such as climate change require consideration of SOC stock changes at the global and biosphere scale, but human interaction occurs at the landscape scale, with consequences at the pedon, aggregate and particle scales. This review evaluates our understanding of SOC across all these scales in the context of the processes involved in SOC cycling at each scale and with emphasis on stabilizing SOC. Current synergy between science and policy is explored at each scale to determine how well each is represented in the management of SOC. An outline of how SOC might be integrated into a framework of soil security is examined. We conclude that SOC processes at the biosphere to biome scales are not well understood. Instead, SOC has come to be viewed as a large-scale pool subjects to carbon flux. Better understanding exists for SOC processes operating at the scales of the pedon, aggregate and particle. At the landscape scale, the influence of large- and small-scale processes has the greatest interaction and is exposed to the greatest modification through agricultural management. Policy implemented at regional or national scale tends to focus at the landscape scale without due consideration of the larger scale factors controlling SOC or the impacts of policy for SOC at the smaller SOC scales. What is required is a framework that can be integrated across a continuum of scales to optimize SOC management.

  1. Soil organic carbon across scales.

    PubMed

    O'Rourke, Sharon M; Angers, Denis A; Holden, Nicholas M; McBratney, Alex B

    2015-10-01

    Mechanistic understanding of scale effects is important for interpreting the processes that control the global carbon cycle. Greater attention should be given to scale in soil organic carbon (SOC) science so that we can devise better policy to protect/enhance existing SOC stocks and ensure sustainable use of soils. Global issues such as climate change require consideration of SOC stock changes at the global and biosphere scale, but human interaction occurs at the landscape scale, with consequences at the pedon, aggregate and particle scales. This review evaluates our understanding of SOC across all these scales in the context of the processes involved in SOC cycling at each scale and with emphasis on stabilizing SOC. Current synergy between science and policy is explored at each scale to determine how well each is represented in the management of SOC. An outline of how SOC might be integrated into a framework of soil security is examined. We conclude that SOC processes at the biosphere to biome scales are not well understood. Instead, SOC has come to be viewed as a large-scale pool subjects to carbon flux. Better understanding exists for SOC processes operating at the scales of the pedon, aggregate and particle. At the landscape scale, the influence of large- and small-scale processes has the greatest interaction and is exposed to the greatest modification through agricultural management. Policy implemented at regional or national scale tends to focus at the landscape scale without due consideration of the larger scale factors controlling SOC or the impacts of policy for SOC at the smaller SOC scales. What is required is a framework that can be integrated across a continuum of scales to optimize SOC management. PMID:25918852

  2. Carbonate Mineralization of Volcanic Province Basalts

    SciTech Connect

    Schaef, Herbert T.; McGrail, B. Peter; Owen, Antionette T.

    2010-03-31

    Flood basalts are receiving increasing attention as possible host formations for geologic sequestration of anthropogenic CO2, with studies underway in the United States, India, Iceland, and Canada. As an extension of our previous experiments with Columbia River basalt, basalts from the eastern United States, India, and South Africa were reacted with aqueous dissolved CO2 and aqueous dissolved CO2-H2S mixtures under supercritical CO2 (scCO2) conditions to study the geochemical reactions resulting from injection of CO2 in such formations. The results of these studies are consistent with cation release behavior measured in our previous experiments (in press) for basalt samples tested in single pass flow through dissolution experiments under dilute solution and mildly acidic conditions. Despite the basalt samples having similar bulk chemistry, mineralogy and apparent dissolution kinetics, long-term static experiments show significant differences in rates of mineralization as well as compositions and morphologies of precipitates that form when the basalts are reacted with CO2-saturated water. For example, basalt from the Newark Basin in the United States was by far the most reactive of any basalt tested to date. Carbonate reaction products for the Newark Basin basalt were globular in form and contained significantly more Fe than the secondary carbonates that precipitated on the other basalt samples. In comparison, the post-reacted samples associated with the Columbia River basalts from the United States contained calcite grains with classic dogtooth spar morphology and trace cation substitution (Mg and Mn). Carbonation of the other basalts produced precipitates with compositions that varied chemically throughout the entire testing period. Examination of polished cross sections of the reacted grains by scanning electron microscopy and energy dispersive x-ray spectroscopy show precipitate overgrowths with varying chemical compositions. Compositional differences in the

  3. Carbon and nitrogen mineralization are decoupled in organo-mineral fractions

    NASA Astrophysics Data System (ADS)

    Bimüller, Carolin; Mueller, Carsten W.; von Lützow, Margit; Kreyling, Olivia; Kölbl, Angelika; Haug, Stephan; Schloter, Michael; Kögel-Knabner, Ingrid

    2015-04-01

    To improve our comprehension how carbon and nitrogen mineralization are linked in soils, we used a controlled laboratory mineralization approach and compared carbon and nitrogen dynamics in the bulk soil and in soil fractions. Topsoil of a Rendzic Leptosol from a beech forest site near Tuttlingen, Germany, was fractionated into three particle size classes: sand (2000 to 20 µm), silt (20 to 2 µm), and clay (< 2 µm). Bulk soil and particle size fractions were incubated for 40 weeks allowing periodic destructive sampling. We monitored carbon and nitrogen mineralization dynamics, and assessed carbon respiration as well as nitrogen mineralization and microbial biomass carbon and nitrogen contents. Soil organic matter in the incubated fractions was considered by a subsequent density fractionation. The chemical composition of selected samples was qualitatively evaluated by 13C-NMR spectroscopy. When summing up the mineralization rates of the single fractions, the values for respired carbon equaled the bulk soil, whereas the mathematical recombination of mineral nitrogen in all fractions was significantly less than in bulk soil. Hence, carbon mineralization was not affected by the damage of the aggregated soil structure via fractionation, whereas nitrogen mineralization was reduced. Fractionation increased the surface area providing accessory mineral surfaces, which allowed new binding of especially nitrogen-rich compounds, besides ammonium fixation via cation exchange. Density fractionation revealed that organic matter in the sand fraction contained mainly particulate organic matter present as light material comprising partly decomposed plant remnants. The organic matter in the clay fraction was mostly adsorbed on mineral surfaces. Organic matter in the sand and in the clay fraction was dominated by O/N-alkyl C indicating low recalcitrance, but the C/N ratio of organic matter narrowed with decreasing particle size. These results also imply that the C/N ratio as well as

  4. Chemically Accelerated Carbon Mineralization: Chemical and Biological Catalytic Enhancement of Weathering of Silicate Minerals as Novel Carbon Capture and Storage

    SciTech Connect

    2010-07-01

    IMPACCT Project: Columbia University is developing a process to pull CO2 out of the exhaust gas of coal-fired power plants and turn it into a solid that can be easily and safely transported, stored above ground, or integrated into value-added products (e.g. paper filler, plastic filler, construction materials, etc.). In nature, the reaction of CO2 with various minerals over long periods of time will yield a solid carbonate—this process is known as carbon mineralization. The use of carbon mineralization as a CO2 capture and storage method is limited by the speeds at which these minerals can be dissolved and CO2 can be hydrated. To facilitate this, Columbia University is using a unique process and a combination of chemical catalysts which increase the mineral dissolution rate, and the enzymatic catalyst carbonic anhydrase which speeds up the hydration of CO2.

  5. Mineral carbonation in water-unsaturated porous media

    NASA Astrophysics Data System (ADS)

    Harrison, A. L.; Dipple, G. M.; Mayer, K. U.; Power, I. M.

    2014-12-01

    Ultramafic mine tailings have an untapped capacity to sequester CO2 directly from air or CO2-rich gas streams via carbonation of tailings minerals [1]. The CO2 sequestration capacity of these sites could be exploited simply by increasing the supply of CO2 into tailings, such as through circulation of air or flue gas from mine site power plants [1,2]. Mine tailings storage facilities typically have heterogeneously distributed pore water [1], affecting both the reactive capacity of the porous medium and the exposure of reactive phases to CO2 [3]. We examine the physical reaction processes that govern carbonation efficiency in variably saturated porous media using meter-scale column experiments containing the tailings mineral, brucite [Mg(OH)2], that were supplied with 10% CO2 gas streams. The experiments were instrumented with water content and gas phase CO2 sensors to track changes in water saturation and CO2concentration with time. The precipitation of hydrated Mg-carbonates as rinds encasing brucite particles resulted in passivation of brucite surfaces and an abrupt shut down of the reaction prior to completion. Moreover, the extent of reaction was further limited at low water saturation due to the lack of water available to form hydrated Mg-carbonates, which incorporate water into their crystal structures. Reactive transport modeling using MIN3P-DUSTY [4] revealed that the instantaneous reaction rate was not strongly affected by water saturation, but the reactive capacity was reduced significantly. Surface passivation and water-limited reaction resulted in a highly non-geometric evolution of reactive surface area. The extent of reaction was also limited at high water content because viscous fingering of the gas streams injected at the base of the columns resulted in narrow zones of highly carbonated material, but left a large proportion of brucite unreacted. The implication is that carbonation efficiency in mine tailings could be maximized by targeting an

  6. Carbon Mineralization Using Phosphate and Silicate Ions

    NASA Astrophysics Data System (ADS)

    Gokturk, H.

    2013-12-01

    ions would enhance the absorption of CO2 into the aerosol even more than the singly or doubly charged ions. Ion containing aerosols also help to catalyze reactions between water and CO2. Hydrated phosphate and silicate ions tend to attract hydrogen atoms from neighboring water molecules to reduce the charged state. When there is CO2 in the vicinity of the ion, the remainder of the water molecule which loses the hydrogen(s) reacts with CO2 to form carbonates. (PO4---) + H2O + CO2 -> (HPO3--) + (HCO3-) (SiO4----) + H2O + CO2 -> (HSiO4---) + (HCO3-) (SiO4----) + H2O + CO2 -> (H2SiO4--) + (CO3--) In conclusion, highly charged phosphate and silicate ions dissolved in water and aerosolized into small droplets can facilitate both the capture and the mineralization of CO2. This method would be especially effective in a CO2 rich environment such as the exhaust gas of a combustion process. [1] H. Gokturk, "Geoengineering with Charged Droplets," AGU Fall Meeting, San Francisco 2011 [2] H. Gokturk, "Atomistic Simulation of Sea Spray Particles," AGU Fall Meeting, San Francisco 2012

  7. Clay mineral continental amplifier for marine carbon sequestration in a greenhouse ocean.

    PubMed

    Kennedy, Martin J; Wagner, Thomas

    2011-06-14

    The majority of carbon sequestration at the Earth's surface occurs in marine continental margin settings within fine-grained sediments whose mineral properties are a function of continental climatic conditions. We report very high mineral surface area (MSA) values of 300 and 570 m(2) g in Late Cretaceous black shales from Ocean Drilling Program site 959 of the Deep Ivorian Basin that vary on subcentennial time scales corresponding with abrupt increases from approximately 3 to approximately 18% total organic carbon (TOC). The observed MSA changes with TOC across multiple scales of variability and on a sample-by-sample basis (centimeter scale), provides a rigorous test of a hypothesized influence on organic carbon burial by detrital clay mineral controlled MSA. Changes in TOC also correspond with geochemical and sedimentological evidence for water column anoxia. Bioturbated intervals show a lower organic carbon loading on mineral surface area of 0.1 mg-OC m(-2) when compared to 0.4 mg-OC m(-2) for laminated and sulfidic sediments. Although either anoxia or mineral surface protection may be capable of producing TOC of < 5%, when brought together they produced the very high TOC (10-18%) apparent in these sediments. This nonlinear response in carbon burial resulted from minor precession-driven changes of continental climate influencing clay mineral properties and runoff from the African continent. This study identifies a previously unrecognized land-sea connection among continental weathering, clay mineral production, and anoxia and a nonlinear effect on marine carbon sequestration during the Coniacian-Santonian Oceanic Anoxic Event 3 in the tropical eastern Atlantic.

  8. Clay mineral continental amplifier for marine carbon sequestration in a greenhouse ocean

    PubMed Central

    Kennedy, Martin J.; Wagner, Thomas

    2011-01-01

    The majority of carbon sequestration at the Earth’s surface occurs in marine continental margin settings within fine-grained sediments whose mineral properties are a function of continental climatic conditions. We report very high mineral surface area (MSA) values of 300 and 570 m2 g in Late Cretaceous black shales from Ocean Drilling Program site 959 of the Deep Ivorian Basin that vary on subcentennial time scales corresponding with abrupt increases from approximately 3 to approximately 18% total organic carbon (TOC). The observed MSA changes with TOC across multiple scales of variability and on a sample-by-sample basis (centimeter scale), provides a rigorous test of a hypothesized influence on organic carbon burial by detrital clay mineral controlled MSA. Changes in TOC also correspond with geochemical and sedimentological evidence for water column anoxia. Bioturbated intervals show a lower organic carbon loading on mineral surface area of 0.1 mg-OC m-2 when compared to 0.4 mg-OC m-2 for laminated and sulfidic sediments. Although either anoxia or mineral surface protection may be capable of producing TOC of < 5%, when brought together they produced the very high TOC (10–18%) apparent in these sediments. This nonlinear response in carbon burial resulted from minor precession-driven changes of continental climate influencing clay mineral properties and runoff from the African continent. This study identifies a previously unrecognized land–sea connection among continental weathering, clay mineral production, and anoxia and a nonlinear effect on marine carbon sequestration during the Coniacian-Santonian Oceanic Anoxic Event 3 in the tropical eastern Atlantic. PMID:21576498

  9. Sequestering CO(2) by mineral carbonation: stability against acid rain exposure.

    PubMed

    Allen, Daniel J; Brent, Geoff F

    2010-04-01

    Mineral carbonation is a potentially attractive alternative to storage of compressed CO(2) in underground repositories, known as geosequestration. Processes for the conversion of basic ores, such as magnesium silicates, to carbonates have been proposed by various researchers, with storage of the carbonate as backfill in the original mine representing a solid carbon sink. The stability of such carbon sinks against acid rain and other sources of strong acids is examined here. It is acknowledged that in the presence of strong acid, carbonates will dissolve and release carbon dioxide. A sensitivity analysis covering annual average rainfall and pH that may be encountered in industrialized areas of the United States, China, Europe, and Australia was conducted to determine maximum CO(2) rerelease rates from mineral carbonation carbon sinks. This analysis is based on a worst-case premise that is equivalent to assuming infinitely rapid kinetics of dissolution of the carbonate. The analysis shows that under any likely conditions of pH and rainfall, leakage rates of stored CO(2) are negligible. This is illustrated in a hypothetical case study under Australian conditions. It is thus proposed that sequestration by mineral carbonation can be considered to be permanent on practical human time scales. Other possible sources of acid have also been considered.

  10. Sequestering CO(2) by mineral carbonation: stability against acid rain exposure.

    PubMed

    Allen, Daniel J; Brent, Geoff F

    2010-04-01

    Mineral carbonation is a potentially attractive alternative to storage of compressed CO(2) in underground repositories, known as geosequestration. Processes for the conversion of basic ores, such as magnesium silicates, to carbonates have been proposed by various researchers, with storage of the carbonate as backfill in the original mine representing a solid carbon sink. The stability of such carbon sinks against acid rain and other sources of strong acids is examined here. It is acknowledged that in the presence of strong acid, carbonates will dissolve and release carbon dioxide. A sensitivity analysis covering annual average rainfall and pH that may be encountered in industrialized areas of the United States, China, Europe, and Australia was conducted to determine maximum CO(2) rerelease rates from mineral carbonation carbon sinks. This analysis is based on a worst-case premise that is equivalent to assuming infinitely rapid kinetics of dissolution of the carbonate. The analysis shows that under any likely conditions of pH and rainfall, leakage rates of stored CO(2) are negligible. This is illustrated in a hypothetical case study under Australian conditions. It is thus proposed that sequestration by mineral carbonation can be considered to be permanent on practical human time scales. Other possible sources of acid have also been considered. PMID:20199068

  11. A literature review of actinide-carbonate mineral interactions

    SciTech Connect

    Stout, D.L.; Carroll, S.A.

    1993-10-01

    Chemical retardation of actinides in groundwater systems is a potentially important mechanism for assessing the performance of the Waste Isolation Pilot Plant (WIPP), a facility intended to demonstrate safe disposal of transuranic waste. Rigorous estimation of chemical retardation during transport through the Culebra Dolomite, a water-bearing unit overlying the WIPP, requires a mechanistic understanding of chemical reactions between dissolved elements and mineral surfaces. This report represents a first step toward this goal by examining the literature for pertinent experimental studies of actinide-carbonate interactions. A summary of existing models is given, along with the types of experiments on which these models are based. Articles pertaining to research into actinide interactions with carbonate minerals are summarized. Select articles involving trace element-carbonate mineral interactions are also reviewed and may serve as templates for future research. A bibliography of related articles is included. Americium(III), and its nonradioactive analog neodymium(III), partition strongly from aqueous solutions into carbonate minerals. Recent thermodynamic, kinetic, and surface studies show that Nd is preferentially removed from solution, forming a Nd-Ca carbonate solid solution. Neptunium(V) is rapidly removed from solution by carbonates. Plutonium incorporation into carbonates is complicated by multiple oxidation states. Little research has been done on the radium(H) and thorium(IV) carbonate systems. Removal of uranyl ion from solution by calcite is limited to monolayer surface coverage.

  12. Short-Range-Order Mineral Physical Protection On Black Carbon Stabilization

    NASA Astrophysics Data System (ADS)

    Liang, B.; Weng, Y. T.; Wang, C. C.; Song, Y. F.; Lehmann, J.; Wang, C. H.

    2015-12-01

    Soil organic matter is one of the largest reservoirs in global carbon cycle, and black carbon (BC) represents a chemical resistant component. Black C plays an important role in global climate change. Generally considered recalcitrant due to high aromaticity, the reactive surface and functional groups of BC are crucial for carbon sequestration in soils. Mineral sorption and physical protection is an important mechanism for BC long term stabilization and sequestration in environments. Previous studies on mineral protection of BC were limited to analysis techniques in two-dimensions, for example, by SEM, TEM, and NanoSIMS. Little is known about the scope of organo-mineral association, the in-situ distribution and forms of minerals, and the ultimate interplay of BC and minerals. The aim of this study is to investigate the three-dimensional interaction of organic C and minerals in submicron scale using synchrotron-based Transmission X-ray Microcopy (TXM) and Fourier-Transform Infrared Spectroscopy (FTIR). Abundant poorly-crystallined nano-minerals particles were observed. These short-range-order (SRO) minerals also aggregate into clusters and sheets, and form envelops-like structures on the surface of BC. On top of large surface contact area, the intimate interplay between BC and minerals reinforces the stability of both organic C and minerals, resulting from chemical bonding through cation bridging and ligand exchange. The mineral protection enhances BC stabilization and sequestration and lowers its bioavailability in environment. The results suggest that mineral physical protection for BC sequestration may be more important than previous understanding.

  13. Integrated Experimental and Modeling Studies of Mineral Carbonation as a Mechanism for Permanent Carbon Sequestration in Mafic/Ultramafic Rocks

    SciTech Connect

    Wang, Zhengrong; Qiu, Lin; Zhang, Shuang; Bolton, Edward; Bercovici, David; Ague, Jay; Karato, Shun-Ichiro; Oristaglio, Michael; Zhu, Wen-Iu; Lisabeth, Harry; Johnson, Kevin

    2014-09-30

    implementation; moreover, enormous volumes of basalt near Earth’s surface are candidate locations for large-scale injection programs. The geochemical experiments do indicate, however, that there will be significant engineering challenges in maintaining high rates of carbonation, by delaying the onset of chemical conditions that promote formation of secondary silicate minerals and, therefore, slow down, or even reverse, the carbonation process. It remains an open question as to whether carbonation processes can be sustained for many years in an engineered system operating on a large scale—a scale capable of accommodating millions of tons of CO2 annually. The development of realistic theoretical models that can systematically describe the combined effects of reactive flow, precipitation and geomechanical deformation is a major barrier to further understanding of the practical viability of mineral carbonation as large-scale method of carbon sequestration.

  14. Microbially mediated mineral carbonation: roles of phototrophy and heterotrophy.

    PubMed

    Power, Ian M; Wilson, Siobhan A; Small, Darcy P; Dipple, Gregory M; Wan, Wankei; Southam, Gordon

    2011-10-15

    Ultramafic mine tailings from the Diavik Diamond Mine, Canada and the Mount Keith Nickel Mine, Western Australia are valuable feedstocks for sequestering CO₂ via mineral carbonation. In microcosm experiments, tailings were leached using various dilute acids to produce subsaline solutions at circumneutral pH that were inoculated with a phototrophic consortium that is able to induce carbonate precipitation. Geochemical modeling of the experimental solutions indicates that up to 2.5% and 16.7% of the annual emissions for Diavik and Mount Keith mines, respectively, could be sequestered as carbonate minerals and phototrophic biomass. CO₂ sequestration rates are mainly limited by cation availability and the uptake of CO₂. Abundant carbonate mineral precipitation occurred when heterotrophic oxidation of acetate acted as an alternative pathway for CO₂ delivery. These experiments highlight the importance of heterotrophy in producing sufficient DIC concentrations while phototrophy causes alkalinization of waters and produces biomass (fatty acids = 7.6 wt.%), a potential feedstock for biofuel production. Tailings storage facilities could be redesigned to promote CO₂ sequestration by directing leachate waters from tailings piles into specially designed ponds where carbonate precipitation would be mediated by both chemical and biological processes, thereby storing carbon in stable carbonate minerals and potentially valuable biomass. PMID:21879741

  15. Mineral protection of soil carbon counteracted by root exudates

    DOE PAGESBeta

    Keiluweit, Marco; Bougoure, Jeremy J.; Nico, Peter S.; Pett-Ridge, Jennifer; Weber, Peter K.; Kleber, Markus

    2015-03-30

    Multiple lines of existing evidence suggest that climate change enhances root exudation of organic compounds into soils. Recent experimental studies show that increased exudate inputs may cause a net loss of soil carbon. This stimulation of microbial carbon mineralization (‘priming’) is commonly rationalized by the assumption that exudates provide a readily bioavailable supply of energy for the decomposition of native soil carbon (co-metabolism). Here we show that an alternate mechanism can cause carbon loss of equal or greater magnitude. We find that a common root exudate, oxalic acid, promotes carbon loss by liberating organic compounds from protective associations with minerals.more » By enhancing microbial access to previously mineral-protected compounds, this indirect mechanism accelerated carbon loss more than simply increasing the supply of energetically more favourable substrates. Lastly, our results provide insights into the coupled biotic–abiotic mechanisms underlying the ‘priming’ phenomenon and challenge the assumption that mineral-associated carbon is protected from microbial cycling over millennial timescales.« less

  16. Carbon mineralization pathways and bioturbation in coastal Brazilian sediments

    PubMed Central

    Quintana, Cintia O.; Shimabukuro, Maurício; Pereira, Camila O.; Alves, Betina G. R.; Moraes, Paula C.; Valdemarsen, Thomas; Kristensen, Erik; Sumida, Paulo Y. G.

    2015-01-01

    Carbon mineralization processes and their dependence on environmental conditions (e.g. through macrobenthic bioturbation) have been widely studied in temperate coastal sediments, but almost nothing is known about these processes in subtropical coastal sediments. This study investigated pathways of organic carbon mineralization and associated effects of macrobenthic bioturbation in winter and summer (September 2012 and February 2014) at the SE Brazilian coast. Iron reduction (FeR) was responsible for 73–81% of total microbial carbon mineralization in September 2012 and 32–61% in February 2014. Similar high rates of FeR have only been documented a few times in coastal sediments and can be sustained by the presence of large bioturbators. Denitrification accounted for 5–27% of total microbial carbon mineralization while no SO42− reduction was detected in any season. Redox profiles suggested that conditions were less reduced in February 2014 than in September 2012, probably associated with low reactivity of the organic matter, higher rates of aerobic respiration and bioirrigation by the higher density of small-macrofauna. Bioturbation by small macrofauna may maintain the sediment oxidized in summer, while large-sized species stimulate the reoxidation of reduced compounds throughout the year. Therefore, bioturbation seems to have an important role modulating the pathways of carbon mineralization in the area. PMID:26525137

  17. Carbon mineralization pathways and bioturbation in coastal Brazilian sediments.

    PubMed

    Quintana, Cintia O; Shimabukuro, Maurício; Pereira, Camila O; Alves, Betina G R; Moraes, Paula C; Valdemarsen, Thomas; Kristensen, Erik; Sumida, Paulo Y G

    2015-01-01

    Carbon mineralization processes and their dependence on environmental conditions (e.g. through macrobenthic bioturbation) have been widely studied in temperate coastal sediments, but almost nothing is known about these processes in subtropical coastal sediments. This study investigated pathways of organic carbon mineralization and associated effects of macrobenthic bioturbation in winter and summer (September 2012 and February 2014) at the SE Brazilian coast. Iron reduction (FeR) was responsible for 73-81% of total microbial carbon mineralization in September 2012 and 32-61% in February 2014. Similar high rates of FeR have only been documented a few times in coastal sediments and can be sustained by the presence of large bioturbators. Denitrification accounted for 5-27% of total microbial carbon mineralization while no SO4(2-) reduction was detected in any season. Redox profiles suggested that conditions were less reduced in February 2014 than in September 2012, probably associated with low reactivity of the organic matter, higher rates of aerobic respiration and bioirrigation by the higher density of small-macrofauna. Bioturbation by small macrofauna may maintain the sediment oxidized in summer, while large-sized species stimulate the reoxidation of reduced compounds throughout the year. Therefore, bioturbation seems to have an important role modulating the pathways of carbon mineralization in the area.

  18. Earthworms facilitate carbon sequestration through unequal amplification of carbon stabilization compared with mineralization.

    PubMed

    Zhang, Weixin; Hendrix, Paul F; Dame, Lauren E; Burke, Roger A; Wu, Jianping; Neher, Deborah A; Li, Jianxiong; Shao, Yuanhu; Fu, Shenglei

    2013-01-01

    A recent review concluded that earthworm presence increases CO₂ emissions by 33% but does not affect soil organic carbon stocks. However, the findings are controversial and raise new questions. Here we hypothesize that neither an increase in CO₂ emission nor in stabilized carbon would entirely reflect the earthworms' contribution to net carbon sequestration. We show how two widespread earthworm invaders affect net carbon sequestration through impacts on the balance of carbon mineralization and carbon stabilization. Earthworms accelerate carbon activation and induce unequal amplification of carbon stabilization compared with carbon mineralization, which generates an earthworm-mediated 'carbon trap'. We introduce the new concept of sequestration quotient to quantify the unequal processes. The patterns of CO₂ emission and net carbon sequestration are predictable by comparing sequestration quotient values between treatments with and without earthworms. This study clarifies an ecological mechanism by which earthworms may regulate the terrestrial carbon sink.

  19. Earthworms facilitate carbon sequestration through unequal amplification of carbon stabilization compared with mineralization

    NASA Astrophysics Data System (ADS)

    Zhang, Weixin; Hendrix, Paul F.; Dame, Lauren E.; Burke, Roger A.; Wu, Jianping; Neher, Deborah A.; Li, Jianxiong; Shao, Yuanhu; Fu, Shenglei

    2013-10-01

    A recent review concluded that earthworm presence increases CO2 emissions by 33% but does not affect soil organic carbon stocks. However, the findings are controversial and raise new questions. Here we hypothesize that neither an increase in CO2 emission nor in stabilized carbon would entirely reflect the earthworms’ contribution to net carbon sequestration. We show how two widespread earthworm invaders affect net carbon sequestration through impacts on the balance of carbon mineralization and carbon stabilization. Earthworms accelerate carbon activation and induce unequal amplification of carbon stabilization compared with carbon mineralization, which generates an earthworm-mediated ‘carbon trap’. We introduce the new concept of sequestration quotient to quantify the unequal processes. The patterns of CO2 emission and net carbon sequestration are predictable by comparing sequestration quotient values between treatments with and without earthworms. This study clarifies an ecological mechanism by which earthworms may regulate the terrestrial carbon sink.

  20. Catalysis of carbon monoxide methanation by deep sea manganate minerals

    NASA Technical Reports Server (NTRS)

    Cabrera, A. L.; Maple, M. B.; Arrhenius, G.

    1990-01-01

    The catalytic activity of deep sea manganese nodule minerals for the methanation of carbon monoxide was measured with a microcatalytic technique between 200 and 460 degrees C. The manganate minerals were activated at 248 degrees C by immersion into a stream of hydrogen in which pulses of carbon monoxide were injected. Activation energies for the methanation reaction and hydrogen desorption from the manganate minerals were obtained and compared with those of pure nickel. Similar energy values indicate that the activity of the nodule materials for the reaction appears to be related to the amount of reducible transition metals present in the samples (ca. 11 wt.-%). Since the activity of the nodule minerals per gram is comparable to that of pure nickel, most of the transition metal ions located between manganese oxide layers appear to be exposed and available to catalyze the reaction.

  1. Experimental study of pattern formation during carbon dioxide mineralization

    NASA Astrophysics Data System (ADS)

    Schuszter, Gabor; Brau, Fabian; de Wit, Anne

    2015-11-01

    Injection of supercritical carbon dioxide in deep porous aquifers, where mineral carbonation takes place via chemical reactions, is one of the possible long-term storage of this greenhouse gas. This mineralization process is investigated experimentally under controlled conditions in a confined horizontal Hele-Shaw geometry where an aqueous solution of sodium carbonate is injected radially into a solution of calcium chloride. Precipitation of calcium carbonate in various finger, flower or tube-like patterns is observed in the mixing zone between the two solutions. These precipitation structures and their growth dynamics are studied quantitatively as a function of the parameters of the problem, which are the injection rate and the reactant concentrations. In particular, we show the existence of critical concentrations of reactants above which the amount of the calcium carbonate precipitate produced drops significantly.

  2. Mineral protection of soil carbon counteracted by root exudates [Root exudates counteract mineral control on soil carbon turnover

    SciTech Connect

    Keiluweit, Marco; Bougoure, Jeremy J.; Nico, Peter S.; Pett-Ridge, Jennifer; Weber, Peter K.; Kleber, Markus

    2015-03-30

    Multiple lines of existing evidence suggest that climate change enhances root exudation of organic compounds into soils. Recent experimental studies show that increased exudate inputs may cause a net loss of soil carbon. This stimulation of microbial carbon mineralization (‘priming’) is commonly rationalized by the assumption that exudates provide a readily bioavailable supply of energy for the decomposition of native soil carbon (co-metabolism). Here we show that an alternate mechanism can cause carbon loss of equal or greater magnitude. We find that a common root exudate, oxalic acid, promotes carbon loss by liberating organic compounds from protective associations with minerals. By enhancing microbial access to previously mineral-protected compounds, this indirect mechanism accelerated carbon loss more than simply increasing the supply of energetically more favourable substrates. Lastly, our results provide insights into the coupled biotic–abiotic mechanisms underlying the ‘priming’ phenomenon and challenge the assumption that mineral-associated carbon is protected from microbial cycling over millennial timescales.

  3. Mineral protection of soil carbon counteracted by root exudates [Root exudates counteract mineral control on soil carbon turnover

    DOE PAGESBeta

    Keiluweit, Marco; Bougoure, Jeremy J.; Nico, Peter S.; Pett-Ridge, Jennifer; Weber, Peter K.; Kleber, Markus

    2015-03-30

    Multiple lines of existing evidence suggest that climate change enhances root exudation of organic compounds into soils. Recent experimental studies show that increased exudate inputs may cause a net loss of soil carbon. This stimulation of microbial carbon mineralization (‘priming’) is commonly rationalized by the assumption that exudates provide a readily bioavailable supply of energy for the decomposition of native soil carbon (co-metabolism). Here we show that an alternate mechanism can cause carbon loss of equal or greater magnitude. We find that a common root exudate, oxalic acid, promotes carbon loss by liberating organic compounds from protective associations with minerals.more » By enhancing microbial access to previously mineral-protected compounds, this indirect mechanism accelerated carbon loss more than simply increasing the supply of energetically more favourable substrates. Lastly, our results provide insights into the coupled biotic–abiotic mechanisms underlying the ‘priming’ phenomenon and challenge the assumption that mineral-associated carbon is protected from microbial cycling over millennial timescales.« less

  4. Bioleaching of serpentine group mineral by fungus Talaromyces flavus: application for mineral carbonation

    NASA Astrophysics Data System (ADS)

    Li, Z.; Lianwen, L.; Zhao, L.; Teng, H.

    2011-12-01

    Many studies of serpentine group mineral dissolution for mineral carbonation have been published in recent years. However, most of them focus mainly on either physical and chemical processes or on bacterial function, rather than fungal involvement in the bioleaching of serpentine group mineral. Due to the excessive costs of the magnesium dissolution process, finding a lower energy consumption method will be meaningful. A fungal strain Talaromyces flavus was isolated from serpentinic rock of Donghai (China). No study of its bioleaching ability is currently available. It is thus of great significance to explore the impact of T. flavus on the dissolution of serpentine group mineral. Serpentine rock-inhabiting fungi belonging to Acremonium, Alternaria, Aspergillus, Botryotinia, Cladosporium, Clavicipitaceae, Cosmospora, Fusarium, Monascus, Paecilomyces, Penicillium, Talaromyces, Trichoderma were isolated. These strains were chosen on the basis of resistance to magnesium and nickel characterized in terms of minimum inhibiting concentration (MIC). Specifically, the strain Talaromyces flavus has a high tolerance to both magnesium (1 mol/L) and nickel (10 mM/L), and we examine its bioleaching ability on serpentine group mineral. Contact and separation experiments (cut-off 8 000-14 000 Da), as well as three control experiments, were set up for 30 days. At least three repeated tests were performed for each individual experiment. The results of our experiments demonstrate that the bioleaching ability of T. flavus towards serpentine group mineral is evident. 39.39 wt% of magnesium was extracted from lizardite during the bioleaching period in the contact experiment, which showed a dissolution rate at about a constant 0.126 mM/d before reaching equilibrium in 13 days. The amount of solubilized Mg from chrysotile and antigorite were respectively 37.79 wt% and 29.78 wt% in the contact experiment. These results make clear the influence of mineral structure on mineral bioleaching

  5. Molecular simulation of carbon dioxide, brine, and clay mineral interactions and determination of contact angles.

    PubMed

    Tenney, Craig M; Cygan, Randall T

    2014-01-01

    Capture and subsequent geologic storage of CO2 in deep brine reservoirs plays a significant role in plans to reduce atmospheric carbon emission and resulting global climate change. The interaction of CO2 and brine species with mineral surfaces controls the ultimate fate of injected CO2 at the nanoscale via geochemistry, at the pore-scale via capillary trapping, and at the field-scale via relative permeability. We used large-scale molecular dynamics simulations to study the behavior of supercritical CO2 and aqueous fluids on both the hydrophilic and hydrophobic basal surfaces of kaolinite, a common clay mineral. In the presence of a bulk aqueous phase, supercritical CO2 forms a nonwetting droplet above the hydrophilic surface of kaolinite. This CO2 droplet is separated from the mineral surface by distinct layers of water, which prevent the CO2 droplet from interacting directly with the mineral surface. Conversely, both CO2 and H2O molecules interact directly with the hydrophobic surface of kaolinite. In the presence of bulk supercritical CO2, nonwetting aqueous droplets interact with the hydrophobic surface of kaolinite via a mixture of adsorbed CO2 and H2O molecules. Because nucleation and precipitation of minerals should depend strongly on the local distribution of CO2, H2O, and ion species, these nanoscale surface interactions are expected to influence long-term mineralization of injected carbon dioxide.

  6. Fracture sealing by mineral precipitation: The role of small-scale mineral heterogeneity

    NASA Astrophysics Data System (ADS)

    Jones, Trevor A.; Detwiler, Russell L.

    2016-07-01

    Fractures are often leakage pathways for fluid in low-permeability rocks that otherwise act as geologic barriers in the subsurface. Flow of fluids in chemical disequilibrium with fracture surfaces can lead to mineral precipitation and fracture sealing. To directly evaluate the role of small-scale mineral heterogeneity on mineral precipitation, we measured CaCO3 precipitation in a transparent analog fracture that included randomly distributed small-scale regions of CaCO3 on one of the borosilicate surfaces. Steady flow of a well-mixed CaCl2-NaHCO3 solution (log(ΩCaCO3) = 1.44) resulted in significant mineral precipitation during the 82 day experiment. Localized mineral precipitation reduced flow within regions of the fracture, but small-scale reaction-site heterogeneity allowed preferential flow to persist through pathways that contained 82% less area of CaCO3 regions than the fracture-scale average. This resulted in a significant reduction in measured precipitation rate; excluding these effects results in more than an order-of-magnitude underestimation of fracture sealing timescales.

  7. Biologically-Mediated Weathering of Minerals From Nanometre Scale to Environmental Systems

    NASA Astrophysics Data System (ADS)

    Brown, D. J.; Banwart, S. A.; Smits, M. M.; Leake, J. R.; Bonneville, S.; Benning, L. G.; Haward, S. J.; Ragnarsdottir, K.

    2007-12-01

    The Weathering Science Consortium is a multi-disciplinary project that aims to create a step change in understanding how biota control mineral weathering and soil formation (http://www.wun.ac.uk/wsc). Our hypothesis is that rates of biotic weathering are driven by the energy supply from plants to the organisms, controlling their biomass, surface area of contact with minerals and their capacity to interact chemically with minerals. Symbiotic fungal mycorrhiza of 90% of plant species are empowered with an available carbohydrate supply from plants that is unparalleled amongst soil microbes. They develop extensive mycelial networks that intimately contact minerals, which they weather aggressively. We hypothesise that mycorrhiza play a critical role through their focussing of photosynthate energy from plants into sub-surface weathering environments. Our work identifies how these fungal cells, and their secretions, interact with mineral surfaces and affect the rates of nutrient transfer from minerals to the organism. Investigating these living systems allows us to create new concepts and mathematical models that can describe biological weathering and be used in computer simulations of soil weathering dynamics. We are studying these biochemical interactions at 3 levels of observation: 1. At the molecular scale to understand interactions between living cells and minerals and to quantify the chemistry that breaks down the mineral structure; 2. At the soil grain scale to quantify the activity and spatial distribution of the fungi, roots and other organisms (e.g. bacteria) and their effects on the rates at which minerals are dissolved to release nutrients; 3. At soil profile scale to test models for the spatial distribution of active fungi and carbon energy and their seasonal variability and impact on mineral dissolution rates. Here we present early results from molecular and soil grain scale experiments. We have grown pure culture (Suillus bovinus, Paxillus involutus

  8. Carbon sequestration via aqueous olivine mineral carbonation: role of passivating layer formation

    SciTech Connect

    Hamdallah Bearat; Michael J. McKelvy; Andrew V.G. Chizmeshya; Deirdre Gormley; Ryan Nunez; R.W. Carpenter; Kyle Squires; George H. Wolf

    2006-08-01

    CO{sub 2} sequestration via carbonation of widely available low-cost minerals, such as olivine, can permanently dispose of CO{sub 2} in an environmentally benign and a geologically stable form. The paper reports the results of studies of the mechanisms that limit aqueous olivine carbonation reactivity under the optimum sequestration reaction conditions observed to date: 1 M NaCl + 0.64 M NaHCO{sub 3} at T {approx} 185{sup o}C and P{sub CO{sub 2}} {approx} 135 bar. A reaction limiting silica-rich passivating layer (PL) forms on the feedstock grains, slowing carbonate formation and raising process cost. The morphology and composition of the passivating layers are investigated using scanning and transmission electron microscopy and atomic level modeling. Postreaction analysis of feedstock particles, recovered from stirred autoclave experiments at 1500 rpm, provides unequivocal evidence of local mechanical removal (chipping) of PL material, suggesting particle abrasion. This is corroborated by the observation that carbonation increases dramatically with solid particle concentration in stirred experiments. Multiphase hydrodynamic calculations are combined with experiment to better understand the associated slurry-flow effects. Large-scale atomic-level simulations of the reaction zone suggest that the PL possesses a 'glassy' but highly defective SiO{sub 2} structure that can permit diffusion of key reactants. Mitigating passivating layer effectiveness is critical to enhancing carbonation and lowering sequestration process cost. 30 refs., 7 figs.

  9. Monitoring CO2 Sequestration by Mineral Carbonation in Mine Tailings at Thetford Mines, Quebec, Canada

    NASA Astrophysics Data System (ADS)

    Lechat, K.; Lemieux, J. M.; Molson, J. W. H.; Beaudoin, G.; Hebert, R.

    2014-12-01

    Mineral carbonation is considered a permanent option to capture and store atmospheric CO2. This reaction occurs naturally under ambient conditions in ultramafic mining and milling waste. In the region of Thetford Mines, Quebec, chrysotile mining has produced approximately 0.8 Gt of magnesium-rich milling waste, which mainly consists of poorly sorted ultramafic rock fragments (< 10 cm) and chrysotile fibers. To quantify the amount of CO2 that can be captured in the mine wastes of Thetford Mines, two experimental pilot-scale tailings cells were constructed and instrumented for measuring soil temperature, volumetric water content, gas pressure and gas composition, with ambient conditions recorded by an autonomous meteorological station. The cells were monitored for water geochemistry, carbon content and mineralogy, with the objective to better understand the mineral carbonation processes under natural conditions and to propose a conceptual model for mineral carbonation at the pilot scale. To validate this model, numerical simulations with the MIN3P reactive transport code have been carried out. The chemical composition of the cell leachate (pH > 10, Mg from 85 to 140 mg.L-1, and high total alkalinity from 260 to 300 mg.L-1 CaCO3) is consistent with active CO2 mineralization reactions within the cell. SEM analyses show precipitation of dypingite with a lamellar texture and cemented grain surfaces. The milling waste contains up to 1.2% C, which indicates CO2 sequestration by mineral carbonation. Measured CO2 concentrations in the interstitial air are also ten times lower than in the atmosphere. Analysis of seasonal variations in fluid flow and heat transfer (essentially by thermal conduction) shows that molecular diffusion is the main process for CO2 supply within the experimental cells. These observations have helped develop a conceptual model for mineral carbonation in the wastes and were used to calibrate the reactive transport model.

  10. Review of Distribution Coefficients for Radionuclides in Carbonate Minerals

    SciTech Connect

    Sutton, M

    2009-08-14

    An understanding of the transport of radionuclides in carbonate minerals is necessary to be able to predict the fate of (and potentially remediate) radionuclides in the environment. In some environments, carbonate minerals such as calciate, aragonite, dolomite and limestone are present and an understanding of the sorption of radionuclides in these carbonate minerals is therefore advantageous. A list of the radionuclides of interest is given in Table 1. The distribution coefficient, K{sub d} is defined as the ratio of the contaminant concentration bound on the solid phase to the contaminant concentration remaining in the liquid phase at equilibrium. Some authors report distribution coefficients and other report partition coefficients, the data presented in this work assumes equality between these two terms, and data are presented and summarized in this work as logarithmic distribution coefficient (log K{sub D}). Published literature was searched using two methods. Firstly, the JNC Sorption Database, namely Shubutani et al (1999), and Suyama and Sasamoto (2004) was used to select elements of interest and a number of carbonate minerals. Secondly, on-line literature search tools were used to locate relevant published articles from 1900 to 2009. Over 300 data points covering 16 elements (hydrogen, carbon, calcium, nickel, strontium, technetium, palladium, iodine, cesium, samarium, europium, holmium, uranium, neptunium, plutonium and americium) were used to calculate an average and range of log K{sub d} values for each element. Unfortunately, no data could be found for chlorine, argon, krypton, zirconium, niobium, tin, thorium and curium. A description of the data is given below, together with the average, standard deviation, minimum, maximum and number of inputs for radionuclide K{sub d} values for calcite, aragonate, limestone, dolomite and unidentified carbonate rocks in Table 2. Finally, the data are condensed into one group (carbonate minerals) of data for each

  11. Black Carbon, The Pyrogenic Clay Mineral?

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Most soils contain significant amounts of black carbon, much of which is present as discrete particles admixed with the coarse clay fraction (0.2–2.0 µm e.s.d.) and can be physically separated from the more abundant diffuse biogenic humic materials. Recent evidence has shown that naturally occurring...

  12. Reaction Kinetics of CO2 Carbonation with Mg-Rich Minerals

    SciTech Connect

    Kwon, Dr. Soonchul; Fan, Maohong; DaCosta, Dr. Herbert F.M.; Russell, Dr. Armistead; Tsouris, Costas

    2011-01-01

    Due to their low price, wide availability, and stability of the resulting carbonates, Mg-rich minerals are promising materials for carbonating CO{sub 2}. Direct carbonation of CO{sub 2} with Mg-rich minerals reported in this research for the first time could be considerably superior to conventional liquid extraction processes from an energy consumption perspective due to its avoidance of the use of a large amount of water with high specific heat capacity and latent heat of vaporization. Kinetic models of the reactions of the direct CO{sub 2} carbonation with Mg-rich minerals and within simulated flue gas environments are important to the scale-up of reactor designs. Unfortunately, such models have not been made available thus far. This research was initiated to fill that gap. Magnesium silicate (Mg{sub 2}SiO{sub 4}), a representative compound in Mg-rich minerals, was used to study CO{sub 2} carbonation reaction kinetics under given simulated flue gas conditions. It was found that the chosen sorbent deactivation model fits well the experimental data collected under given conditions. A reaction order of 1 with respect to CO{sub 2} is obtained from experimental data. The Arrhenius form of CO{sub 2} carbonation with Mg{sub 2}SiO{sub 4} is established based on changes in the rate constants of the chosen deactivation model as a function of temperature.

  13. Rapid carbon mineralization for permanent disposal of anthropogenic carbon dioxide emissions

    NASA Astrophysics Data System (ADS)

    Matter, Juerg M.; Stute, Martin; Snæbjörnsdottir, Sandra Ó.; Oelkers, Eric H.; Gislason, Sigurdur R.; Aradottir, Edda S.; Sigfusson, Bergur; Gunnarsson, Ingvi; Sigurdardottir, Holmfridur; Gunnlaugsson, Einar; Axelsson, Gudni; Alfredsson, Helgi A.; Wolff-Boenisch, Domenik; Mesfin, Kiflom; Taya, Diana Fernandez de la Reguera; Hall, Jennifer; Dideriksen, Knud; Broecker, Wallace S.

    2016-06-01

    Carbon capture and storage (CCS) provides a solution toward decarbonization of the global economy. The success of this solution depends on the ability to safely and permanently store CO2. This study demonstrates for the first time the permanent disposal of CO2 as environmentally benign carbonate minerals in basaltic rocks. We find that over 95% of the CO2 injected into the CarbFix site in Iceland was mineralized to carbonate minerals in less than 2 years. This result contrasts with the common view that the immobilization of CO2 as carbonate minerals within geologic reservoirs takes several hundreds to thousands of years. Our results, therefore, demonstrate that the safe long-term storage of anthropogenic CO2 emissions through mineralization can be far faster than previously postulated.

  14. Rapid carbon mineralization for permanent disposal of anthropogenic carbon dioxide emissions.

    PubMed

    Matter, Juerg M; Stute, Martin; Snæbjörnsdottir, Sandra Ó; Oelkers, Eric H; Gislason, Sigurdur R; Aradottir, Edda S; Sigfusson, Bergur; Gunnarsson, Ingvi; Sigurdardottir, Holmfridur; Gunnlaugsson, Einar; Axelsson, Gudni; Alfredsson, Helgi A; Wolff-Boenisch, Domenik; Mesfin, Kiflom; Fernandez de la Reguera Taya, Diana; Hall, Jennifer; Dideriksen, Knud; Broecker, Wallace S

    2016-06-10

    Carbon capture and storage (CCS) provides a solution toward decarbonization of the global economy. The success of this solution depends on the ability to safely and permanently store CO2 This study demonstrates for the first time the permanent disposal of CO2 as environmentally benign carbonate minerals in basaltic rocks. We find that over 95% of the CO2 injected into the CarbFix site in Iceland was mineralized to carbonate minerals in less than 2 years. This result contrasts with the common view that the immobilization of CO2 as carbonate minerals within geologic reservoirs takes several hundreds to thousands of years. Our results, therefore, demonstrate that the safe long-term storage of anthropogenic CO2 emissions through mineralization can be far faster than previously postulated. PMID:27284192

  15. Theoretical Raman spectra of carbonate minerals

    NASA Astrophysics Data System (ADS)

    Bobocioiu, E.; Caracas, R.

    2011-12-01

    The Raman spectra of the majority of MeCO3 minerals, with Me=alkali elements, calc-alkali elements or combinations thereof, are determined using density functional perturbation theory in the ABINIT implementation. We consider more than a dozen different minerals, most of them with rhombohedral, i.e. calcite-like, or orthorhombic, i.e. aragonite-like, structures [1]. We start with the experimental structure and perform two distinct structural relaxations: one at experimental density, i.e. experimental volume, and one at theoretical 0GPa pressure. During these structural relaxations we minimize the energy, the residual forces on the atoms and the non-hydrostatic stresses on the unit cell. Consequently in the end we obtain to distinct sets of data. We find that the relative intensities of the major Raman peaks are in good agreement with respect to experiment. The positions of the peaks are consistently shifted relative to the experiment. As a general rule, the best agreement between theory and experiment is obtained for the calcualtions performed at experimental density. We find that all spectra are dominated, as expected, by the stretching modes of the planar CO3 groups. Their theoretical frequency varies from as low as 1066 in paralstonite [BaCa(CO3)2] up to high as 1113 cm-1 in eitelite [Na2Mg(CO3)2]. The low-frequency modes are dominated by the heavy cations. Their degeneracy is directly determined by the symmetry of the structure. We performed a detailed comparative study to be able to identify identification trends. Finally we discuss C and O isotope fractionation patterns. We compute log(β) functions based on the vibrational information contained in the Brillouin zone center. Though not complete, this information is already enough to give us a reasonable estimation of the partitioning. Reference: Caracas, R., Bobocioiu, E. (2011) The WURM project - a freely available web-based repository of computed physical data for minerals, American Mineralogist, vol. 96

  16. Pore Scale Heterogeneity in the Mineral Distribution and Surface Area of Porous Rocks

    NASA Astrophysics Data System (ADS)

    Lai, Peter; Krevor, Sam

    2015-04-01

    An important control on rate of interfacial processes between minerals and aqueous solutions such as nucleation of solids, and mineral dissolution and growth is reactive surface area. In geochemical modelling, the continuum hypothesis is based on the assumption that the system can be represented by a sufficiently large number of representative elemental volumes. There has been recent interest in studying the impact of this assumption on reaction-transport coupled systems. In this study, the impact of pore-scale heterogeneity on the distribution of reactive surface area is discussed. 3D images obtained using x-ray micro-tomography were used to characterise the distribution of reactive surface area. The results were compared to independent observations. Mineral identification using x- ray diffraction and fluorescence suggested general agreement with CT analysis. Nitrogen BET surface areas were one to two orders of magnitude higher than measurements from x-ray imagery. Co- registered images of Berea sandstone from x-ray and energy dispersive spectroscopy imagery suggested that quartz, K-feldspar and most clays could be identified. However, minor minerals such as albite and illite did not exhibit enough contrast. In Berea sandstone, mineral surface area fraction was poorly correlated to the mineral volumetric fraction. Clay and feldspar minerals exhibited higher surface area fractions than bulk mineralogy suggested. In contrast, in the Edwards carbonate samples, modal mineral composition correlated with mineral-specific surface area. Berea sandstone revealed a characteristic pore size at which a surface area distribution may be used to quantify heterogeneity. Conversely, the carbonate samples suggested a continuous range of pore sizes across length scales. A comparison with pore network model simulations from the literature was made. First order estimates of mineral specific correlations between geometric area measured in the x-ray images were used to convert the CT

  17. A method for permanent CO2 mineral carbonation

    SciTech Connect

    Dahlin, David C.; O'Connor, William K.; Nilsen, David N.; Rush, G.E.; Walters, Richard P.; Turner, Paul C.

    2000-01-01

    The Albany Research Center (ARC) of the U.S. Department of Energy (DOE) has been conducting research to investigate the feasibility of mineral carbonation as a method for carbon dioxide (CO2) sequestration. The research is part of a Mineral Carbonation Study Program within the Office of Fossil Energy in DOE. Other participants in this Program include DOE?s Los Alamos National Laboratory and National Energy Technology Laboratory, Arizona State University, and Science Applications International Corporation. The research has focused on ex-situ mineral carbonation in an aqueous system. The process developed at ARC reacts a slurry of magnesium silicate mineral with supercritical CO2 to produce a solid magnesium carbonate product. To date, olivine and serpentine have been used as the mineral reactant, but other magnesium silicates could be used as well. The process is designed to simulate the natural serpentinization reaction of ultramafic minerals, and consequently, these results may also be applicable to strategies for in-situ geological sequestration. Baseline tests were begun in distilled water on ground products of foundry-grade olivine. Tests conducted at 150 C and subcritical CO2 pressures (50 atm) resulted in very slow conversion to carbonate. Increasing the partial pressure of CO2 to supercritical (>73 atm) conditions, coupled with agitation of the slurry and gas dispersion within the water column, resulted in significant improvement in the extent of reaction in much shorter reaction times. A change from distilled water to a bicarbonate/salt solution further improved the rate and extent of reaction. When serpentine, a hydrated mineral, was used instead of olivine, extent of reaction was poor until heat treatment was included prior to the carbonation reaction. Removal of the chemically bound water resulted in conversion to carbonate similar to those obtained with olivine. Recent results have shown that conversions of nearly 80 pct are achievable after 30 minutes

  18. Organo-mineral complexation alters carbon and nitrogen cycling in stream microbial assemblages

    NASA Astrophysics Data System (ADS)

    Hunter, William Ross; Wanek, Wolfgang; Prommer, Judith; Mooshammer, Maria; Battin, Tom

    2014-05-01

    Inland waters are of global biogeochemical importance receiving carbon inputs of ~ 4.8 Pg C y-1. Of this 12 % is buried, 18 % transported to the oceans, and 70 % supports aquatic secondary production. However, the mechanisms that determine the fate of organic matter (OM) in these systems are poorly defined. One important aspect is the formation of organo-mineral complexes in aquatic systems and their potential as a route for OM transport and burial vs. microbial utilization as organic carbon (C) and nitrogen (N) sources. Organo-mineral particles form by sorption of dissolved OM to freshly eroded mineral surfaces and may contribute to ecosystem-scale particulate OM fluxes. We tested the availability of mineral-sorbed OM as a C & N source for streamwater microbial assemblages and streambed biofilms. Organo-mineral particles were constructed in vitro by sorption of 13C:15N-labelled amino acids to hydrated kaolin particles, and microbial degradation of these particles compared with equivalent doses of 13C:15N-labelled free amino acids. Experiments were conducted in 120 ml mesocosms over 7 days using biofilms and streamwater sampled from the Oberer Seebach stream (Austria), tracing assimilation and mineralization of 13C and 15N labels from mineral-sorbed and dissolved amino acids. Here we present data on the effects of organo-mineral sorption upon amino acid mineralization and its C:N stoichiometry. Organo-mineral sorption had a significant effect upon microbial activity, restricting C and N mineralization by both the biofilm and streamwater treatments. Distinct differences in community response were observed, with both dissolved and mineral-stabilized amino acids playing an enhanced role in the metabolism of the streamwater microbial community. Mineral-sorption of amino acids differentially affected C & N mineralization and reduced the C:N ratio of the dissolved amino acid pool. The present study demonstrates that organo-mineral complexes restrict microbial degradation

  19. Mineralization of Calcium Carbonate on Multifunctional Peptide Assembly Acting as Mineral Source Supplier and Template.

    PubMed

    Murai, Kazuki; Kinoshita, Takatoshi; Nagata, Kenji; Higuchi, Masahiro

    2016-09-13

    Crystal phase and morphology of biominerals may be precisely regulated by controlled nucleation and selective crystal growth through biomineralization on organic templates such as a protein. We herein propose new control factors of selective crystal growth by the biomineralization process. In this study, a designed β-sheet Ac-VHVEVS-CONH2 peptide was used as a multifunctional template that acted as mineral source supplier and having crystal phase control ability of calcium carbonate (CaCO3) during a self-supplied mineralization. The peptides formed three-dimensional nanofiber networks composed of assembled bilayer β-sheets. The assembly hydrolyzed urea molecules to one carbonate anion and two ammonium cations owing to a charge relay effect between His and Ser residues under mild conditions. CaCO3 was selectively mineralized on the peptide assembly using the generated carbonate anions on the template. Morphology of the obtained CaCO3 was fiber-like structure, similar to that of the peptide template. The mineralized CaCO3 on the peptide template had aragonite phase. This implies that CaCO3 nuclei, generated using the carbonate anions produced by the hydrolysis of urea on the surface of the peptide assembly, preferentially grew into aragonite phase, the growth axis of which aligned parallel to the direction of the β-sheet fiber axis. PMID:27552287

  20. Carbon dioxide sequestration by direct mineral carbonation: process mineralogy of feed and products

    SciTech Connect

    O'Connor, William K.; Dahlin, David C.; Rush, G.E.; Dahlin, Cheryl L.; Collins, W. Keith

    2001-01-01

    Direct mineral carbonation has been investigated as a process to convert gaseous CO2 into a geologically stable final form. The process utilizes a slurry of water, with bicarbonate and salt additions, mixed with a mineral reactant, such as olivine (Mg2SiO4) or serpentine [Mg3Si2O5(OH)4]. Carbon dioxide is dissolved into this slurry, resulting in dissolution of the mineral and precipitation of magnesium carbonate (MgCO3). Optimum results have been achieved using heat pretreated serpentine feed material and high partial pressure of CO2 (PCO2). Specific conditions include: 155?C; PCO2=185 atm; 15% solids. Under these conditions, 78% conversion of the silicate to the carbonate was achieved in 30 minutes. Process mineralogy has been utilized to characterize the feed and process products, and interpret the mineral dissolution and carbonate precipitation reaction paths.

  1. Reverse osmosis desalting of inland brackish water of high gypsum scaling propensity: kinetics and mitigation of membrane mineral scaling.

    PubMed

    Rahardianto, Anditya; McCool, Brian C; Cohen, Yoram

    2008-06-15

    The potential for mineral scaling that may limit the generation of new potable water resources by reverse osmosis (RO), from inland brackish water of high gypsum scaling propensity, was experimentally explored via flux decline measurements and real-time RO membrane surface imaging. Antagonistic gypsum and calcium carbonate scaling kinetics were demonstrated for high-sulfate brackish water desalting. RO scaling studies with brackish water from the California San Joaquin Valley (approximately 10 000 mg/L total dissolved solids) revealed that membrane gypsum scaling was increasingly retarded with rising bicarbonate concentrations. Crystal growth rate, fractional membrane scale coverage, and flux decline decreased by up to about 63, 78, and 73%, respectively, as the bicarbonate concentration increased, at the membrane surface, from < 0.01 to 7.81 mM, for a gypsum saturation index of 2. Inhibition of gypsum crystal growth was attributed to bicarbonate adsorption onto the crystal surfaces, and CaCO3 scaling was undetected even up to a calcite saturation index of approximately 16. Given the suppression of gypsum scaling by bicarbonate, it is essential to considerthis effect in the conventional practice of pH adjustment to suppress CaCO3 scaling. The present results suggest that antagonistic and synergistic mineral crystallization kinetics effects are important for optimizing scale-control strategies (e.g., acid and antiscalants addition to the RO feed).

  2. Reverse osmosis desalting of inland brackish water of high gypsum scaling propensity: kinetics and mitigation of membrane mineral scaling.

    PubMed

    Rahardianto, Anditya; McCool, Brian C; Cohen, Yoram

    2008-06-15

    The potential for mineral scaling that may limit the generation of new potable water resources by reverse osmosis (RO), from inland brackish water of high gypsum scaling propensity, was experimentally explored via flux decline measurements and real-time RO membrane surface imaging. Antagonistic gypsum and calcium carbonate scaling kinetics were demonstrated for high-sulfate brackish water desalting. RO scaling studies with brackish water from the California San Joaquin Valley (approximately 10 000 mg/L total dissolved solids) revealed that membrane gypsum scaling was increasingly retarded with rising bicarbonate concentrations. Crystal growth rate, fractional membrane scale coverage, and flux decline decreased by up to about 63, 78, and 73%, respectively, as the bicarbonate concentration increased, at the membrane surface, from < 0.01 to 7.81 mM, for a gypsum saturation index of 2. Inhibition of gypsum crystal growth was attributed to bicarbonate adsorption onto the crystal surfaces, and CaCO3 scaling was undetected even up to a calcite saturation index of approximately 16. Given the suppression of gypsum scaling by bicarbonate, it is essential to considerthis effect in the conventional practice of pH adjustment to suppress CaCO3 scaling. The present results suggest that antagonistic and synergistic mineral crystallization kinetics effects are important for optimizing scale-control strategies (e.g., acid and antiscalants addition to the RO feed). PMID:18605546

  3. Carbonation of Rock Minerals by Supercritical Carbon Dioxide at 250 degrees C.

    SciTech Connect

    Sugama, T.; Ecker, L.; Butcher, T.

    2010-06-01

    Wet powder-samples of five rock minerals, granite, albite, hornblende, diorite, and biotite mica, were exposed in supercritical carbon dioxide (scCO2) for 3 days at 250 C under 17.23 MPa pressure, and then the susceptibility of the various crystalline phases present in these mineral structures to reactions with hot scCO2 was investigated by XRD and FT-IR. The anorthite present in diorite was identified as the most vulnerable phase to carbonation. In contrast, biotite displayed a great resistance, although its phase was transformed hydrothermally to sanidine and quartz. Granite comprised of two phases, anorthoclase-type albite and quartz. The carbonation of former phase led to the formation of amorphous sodium and potassium carbonates coexisting with the clay-like by-products of the carbonation reaction. The reactivity of quartz to scCO2 was minimal, if any. Among these rock minerals, only hornblende formed crystalline carbonation products, such as calcite and magnesite after exposure, reflecting the likelihood of an increase in its volume. Based upon the feldspar ternary diagram, the carbonation rate of various different minerals in the plagioclase feldspar family depended primarily on the amount of anorthite. On the other hand, alkali feldspar minerals involving anorthoclase-type albite and sanidine had a lower reactivity with scCO2, compared with that of plagioclase feldspar minerals.

  4. Direct Use of Mineral Carbonate for Autotrophy Among Euendolithic Cyanobacteria

    NASA Astrophysics Data System (ADS)

    Guida, B. S.

    2015-12-01

    Cyanobacteria are oxygenic photoautotrophs, and arguably the most important primary producers on the planet, fixing carbon from dissolved inorganic carbon (DIC) in the aquatic environment, and directly from atmospheric CO2 in terrestrial systems. Euendolithic cyanobacteria occupy a very specific niche, inside rocks, which can potentially preclude them from easily accessing those carbon pools, and yet, natural euendolithic communities can support food webs in habitats where they are prominent, such as in marine carbonate platforms and desert carbonate outcrops. In a recently proposed model describing the mechanism of cyanobacterial carbonate boring, we postulated that as the organism dissolves the mineral, liberated CO32- anions will be quickly converted to HCO3- and assimilated directly, making the cyanobacterium independent of external DIC pools for autotrophy. We used natural abundance and tracer stable carbon (13C) isotope analyses accompanied by nanoSIMS imaging in model laboratory systems of cultivated cyanobacteria and in natural mixed communities of marine euendoliths to study the ultimate source of carbon in their biomass. Our results clearly demonstrate that endolithic biomass of these cyanobacteria is significantly derived from mineral carbonate, as opposed to free-living or epilithic biomass, where the source is mixed or coming from the dissolved pool, this holds for model cultures as well as natural communities. In fact, we can increase the lifestyle preference of cultures for endolithic growth versus planktonic or benthic growth, by simply imposing an external DIC limitation in the presence of a carbonate substrate. Our results predict that benthic communities (extant or fossil) that rely heavily on primary production by euendolithic primary producers may show 13C signatures that mimic those of the surrounding carbonate substrate rather than from those of the local seawater.

  5. Mineral CO2 sequestration by steel slag carbonation.

    PubMed

    Huijgen, Wouter J J; Witkamp, Geert-Jan; Comans, Rob N J

    2005-12-15

    Mineral CO2 sequestration, i.e., carbonation of alkaline silicate Ca/Mg minerals, analogous to natural weathering processes, is a possible technology for the reduction of carbon dioxide emissions to the atmosphere. In this paper, alkaline Ca-rich industrial residues are presented as a possible feedstock for mineral CO2 sequestration. These materials are cheap, available near large point sources of CO2, and tend to react relatively rapidly with CO2 due to their chemical instability. Ground steel slag was carbonated in aqueous suspensions to study its reaction mechanisms. Process variables, such as particle size, temperature, carbon dioxide pressure, and reaction time, were systematically varied, and their influence on the carbonation rate was investigated. The maximum carbonation degree reached was 74% of the Ca content in 30 min at 19 bar CO2 pressure, 100 degrees C, and a particle size of <38 microm. The two most important factors determining the reaction rate are particle size (<2 mm to <38 microm) and reaction temperature (25-225 degrees C). The carbonation reaction was found to occur in two steps: (1) leaching of calcium from the steel slag particles into the solution; (2) precipitation of calcite on the surface of these particles. The first step and, more in particular, the diffusion of calcium through the solid matrix toward the surface appeared to be the rate-determining reaction step. The Ca diffusion was found to be hindered by the formation of a CaCO3-coating and a Ca-depleted silicate zone during the carbonation process. Research on further enhancement of the reaction rate, which would contribute to the development of a cost-effective CO2-sequestration process, should focus particularly on this mechanism.

  6. Geophysical Delination of Mg-Rich Ultramafic Rocksfor Mineral Carbon Sequestration

    USGS Publications Warehouse

    McCafferty, Anne E.; Van Gosen, Brad S.; Krevor, Sam C.; Graves, Chris R.

    2009-01-01

    A similar version of this slide presentation was given at the 2009 Society for Mining, Metallurgy, and Exploration (SME) annual meeting in Denver, Colorado, in February 2009. This presentation was part of the 'Industrial Minerals: Reducing Carbon Footprint in Industrial Minerals' session. Two other related talks were presented in the same session by Sam Krevor of Columbia University. The first talk provided a status report on mineral CO2 sequestration as an industrial process. The second talk presented a national-scale geologic compilation of rocks favorable for mineral CO2 sequestration in the United States. This presentation, an extension of the latter talk, shows how airborne geophysical data can be used to further refine the geologic mapping of ultramafic rocks.

  7. Carbon dioxide sequestration by direct mineral carbonation: process mineralogy of feed and products

    SciTech Connect

    O'Connor, William K.; Dahlin, David C.; Rush, G.E.; Dahlin, Cheryl L.; Collins, W. Keith

    2002-05-01

    Direct mineral carbonation was investigated as a process to convert gaseous CO[2] into a geologically stable final form. The process utilizes a slurry of water, with bicarbonate and salt additions, mixed with a mineral reactant, such as olivine (Mg[2]SiO[4]) or serpentine [Mg[3]Si[2]O[5](OH)[4

  8. Pore Scale Heterogeneity in the Mineral Distribution, Surface Area and Adsorption in Porous Rocks

    NASA Astrophysics Data System (ADS)

    Lai, P. E. P.; Krevor, S. C.

    2014-12-01

    The impact of heterogeneity in chemical transport and reaction is not understood in continuum (Darcy/Fickian) models of reactive transport. This is manifested in well-known problems such as scale dependent dispersion and discrepancies in reaction rate observations made at laboratory and field scales [1]. Additionally, this is a source of uncertainty for carbon dioxide injection, which produces a reactive fluid-rock system particularly in carbonate rock reservoirs. A potential cause is the inability of the continuum approach to incorporate the impact of heterogeneity in pore-scale reaction rates. This results in part from pore-scale heterogeneities in surface area of reactive minerals [2, 3]. We use x-ray micro tomography to describe the non-normal 3-dimensional distribution of reactive surface area within a porous medium according to distinct mineral groups. Using in-house image processing techniques, thin sections, nitrogen BET surface area, backscattered electron imaging and energy dispersive spectroscopy, we compare the surface area of each mineral phase to those obtained from x-ray CT imagery. In all samples, there is little correlation between the reactive surface area fraction and the volumetric fraction of a mineral in a bulk rock. Berea sandstone was far less heterogeneous and has a characteristic pore size at which a surface area distribution may be used to quantify heterogeneity. In carbonates, heterogeneity is more complex and surface area must be characterized at multiple length scales for an accurate description of reactive transport. We combine the mineral specific surface area characterisation to dynamic tomography, imaging the flow of water and solutes, to observe flow dependent and mineral specific adsorption. The observations may contribute to the incorporation of experimentally based statistical descriptions of pore scale heterogeneity in reactive transport into upscaled models, moving it closer to predictive capabilities for field scale

  9. Sequestration of Martian CO2 by mineral carbonation

    PubMed Central

    Tomkinson, Tim; Lee, Martin R.; Mark, Darren F.; Smith, Caroline L.

    2013-01-01

    Carbonation is the water-mediated replacement of silicate minerals, such as olivine, by carbonate, and is commonplace in the Earth’s crust. This reaction can remove significant quantities of CO2 from the atmosphere and store it over geological timescales. Here we present the first direct evidence for CO2 sequestration and storage on Mars by mineral carbonation. Electron beam imaging and analysis show that olivine and a plagioclase feldspar-rich mesostasis in the Lafayette meteorite have been replaced by carbonate. The susceptibility of olivine to replacement was enhanced by the presence of smectite veins along which CO2-rich fluids gained access to grain interiors. Lafayette was partially carbonated during the Amazonian, when liquid water was available intermittently and atmospheric CO2 concentrations were close to their present-day values. Earlier in Mars’ history, when the planet had a much thicker atmosphere and an active hydrosphere, carbonation is likely to have been an effective mechanism for sequestration of CO2. PMID:24149494

  10. Sequestration of Martian CO2 by mineral carbonation.

    PubMed

    Tomkinson, Tim; Lee, Martin R; Mark, Darren F; Smith, Caroline L

    2013-01-01

    Carbonation is the water-mediated replacement of silicate minerals, such as olivine, by carbonate, and is commonplace in the Earth's crust. This reaction can remove significant quantities of CO2 from the atmosphere and store it over geological timescales. Here we present the first direct evidence for CO2 sequestration and storage on Mars by mineral carbonation. Electron beam imaging and analysis show that olivine and a plagioclase feldspar-rich mesostasis in the Lafayette meteorite have been replaced by carbonate. The susceptibility of olivine to replacement was enhanced by the presence of smectite veins along which CO2-rich fluids gained access to grain interiors. Lafayette was partially carbonated during the Amazonian, when liquid water was available intermittently and atmospheric CO2 concentrations were close to their present-day values. Earlier in Mars' history, when the planet had a much thicker atmosphere and an active hydrosphere, carbonation is likely to have been an effective mechanism for sequestration of CO2. PMID:24149494

  11. Impacts of diffusive transport on carbonate mineral formation from magnesium silicate-CO2-water reactions.

    PubMed

    Giammar, Daniel E; Wang, Fei; Guo, Bin; Surface, J Andrew; Peters, Catherine A; Conradi, Mark S; Hayes, Sophia E

    2014-12-16

    Reactions of CO2 with magnesium silicate minerals to precipitate magnesium carbonates can result in stable carbon sequestration. This process can be employed in ex situ reactors or during geologic carbon sequestration in magnesium-rich formations. The reaction of aqueous CO2 with the magnesium silicate mineral forsterite was studied in systems with transport controlled by diffusion. The approach integrated bench-scale experiments, an in situ spectroscopic technique, and reactive transport modeling. Experiments were performed using a tube packed with forsterite and open at one end to a CO2-rich solution. The location and amounts of carbonate minerals that formed were determined by postexperiment characterization of the solids. Complementing this ex situ characterization, (13)C NMR spectroscopy tracked the inorganic carbon transport and speciation in situ. The data were compared with the output of reactive transport simulations that accounted for diffusive transport processes, aqueous speciation, and the forsterite dissolution rate. All three approaches found that the onset of magnesium carbonate precipitation was spatially localized about 1 cm from the opening of the forsterite bed. Magnesite was the dominant reaction product. Geochemical gradients that developed in the diffusion-limited zones led to locally supersaturated conditions at specific locations even while the volume-averaged properties of the system remained undersaturated.

  12. Where is mineral ballast important for surface export of particulate organic carbon in the ocean?

    PubMed Central

    Le Moigne, Frédéric A C; Pabortsava, Katsiaryna; Marcinko, Charlotte L J; Martin, Patrick; Sanders, Richard J

    2014-01-01

    Correlations between particulate organic carbon (POC) and mineral fluxes in the deep ocean have inspired the inclusion of “ballast effect” parameterizations in carbon cycle models. A recent study demonstrated regional variability in the effect of ballast minerals on the flux of POC in the deep ocean. We have undertaken a similar analysis of shallow export data from the Arctic, Atlantic, and Southern Oceans. Mineral ballasting is of greatest importance in the high-latitude North Atlantic, where 60% of the POC flux is associated with ballast minerals. This fraction drops to around 40% in the Southern Ocean. The remainder of the export flux is not associated with minerals, and this unballasted fraction thus often dominates the export flux. The proportion of mineral-associated POC flux often scales with regional variation in export efficiency (the proportion of primary production that is exported). However, local discrepancies suggest that regional differences in ecology also impact the magnitude of surface export. We propose that POC export will not respond equally across all high-latitude regions to possible future changes in ballast availability. PMID:26074644

  13. Scanning probe microscopy: Sulfate minerals in scales and cements

    SciTech Connect

    Hall, C.

    1995-11-01

    The principles of scanning probe microscopy (SPM) are illustrated with examples from oilfield mineralogy, particularly emphasizing sulfate minerals involved in scale formation and cement hydration chemistry. The topography of the (010) cleavage surface of gypsum observed by atomic force microscopy shows atomically flat terraces separated by shallow steps often only one unit cell high. SPM allows direct observation of processes on mineral surfaces while they are in contact with solutions. The dissolution etching and crystal growth of gypsum and barite are discussed and rates of step migration estimated. The orientation of steps is related to the crystallographic axes. The action of phosphonate crystal growth inhibitor on gypsum and of a chelating scale solvent on barite are also shown. The multiphase microstructure of an oilwell cement clinker is described in relation to its hydration chemistry in contact with water and its reaction with sulfate ions.

  14. 16 CFR 802.3 - Acquisitions of carbon-based mineral reserves.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 16 Commercial Practices 1 2013-01-01 2013-01-01 false Acquisitions of carbon-based mineral... § 802.3 Acquisitions of carbon-based mineral reserves. (a) An acquisition of reserves of oil, natural... or future exploration or production activities associated with the carbon-based mineral reserves...

  15. 16 CFR 802.3 - Acquisitions of carbon-based mineral reserves.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 16 Commercial Practices 1 2014-01-01 2014-01-01 false Acquisitions of carbon-based mineral... § 802.3 Acquisitions of carbon-based mineral reserves. (a) An acquisition of reserves of oil, natural... or future exploration or production activities associated with the carbon-based mineral reserves...

  16. 16 CFR 802.3 - Acquisitions of carbon-based mineral reserves.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 16 Commercial Practices 1 2012-01-01 2012-01-01 false Acquisitions of carbon-based mineral... § 802.3 Acquisitions of carbon-based mineral reserves. (a) An acquisition of reserves of oil, natural... or future exploration or production activities associated with the carbon-based mineral reserves...

  17. 16 CFR 802.3 - Acquisitions of carbon-based mineral reserves.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 16 Commercial Practices 1 2010-01-01 2010-01-01 false Acquisitions of carbon-based mineral... § 802.3 Acquisitions of carbon-based mineral reserves. (a) An acquisition of reserves of oil, natural... or future exploration or production activities associated with the carbon-based mineral reserves...

  18. Mineral carbonation of gaseous carbon dioxide using a clay-hosted cation exchange reaction.

    PubMed

    Kang, Il-Mo; Roh, Ki-Min

    2013-01-01

    The mineral carbonation method is still a challenge in practical application owing to: (1) slow reaction kinetics, (2) high reaction temperature, and (3) continuous mineral consumption. These constraints stem from the mode of supplying alkaline earth metals through mineral acidification and dissolution. Here, we attempt to mineralize gaseous carbon dioxide into calcium carbonate, using a cation exchange reaction of vermiculite (a species of expandable clay minerals). The mineralization is operated by draining NaCI solution through vermiculite powders and continuously dropping into the pool of NaOH solution with CO2 gas injected. The mineralization temperature is regulated here at 293 and 333 K for 15 min. As a result of characterization, using an X-ray powder diffractometer and a scanning electron microscopy, two types of pure CaCO3 polymorphs (vaterite and calcite) are identified as main reaction products. Their abundance and morphology are heavily dependent on the mineralization temperature. Noticeably, spindle-shaped vaterite, which is quite different from a typical vaterite morphology (polycrystalline spherulite), forms predominantly at 333 K (approximately 98 wt%).

  19. Elemental composition of extant microbialites: mineral and microbial carbon

    NASA Astrophysics Data System (ADS)

    Valdespino-Castillo, P. M.; Falcón, L. I.; Holman, H. Y. N.; Merino-Ibarra, M.; García-Guzmán, M.; López-Gómez, L. M. D. R.; Martínez, J.; Alcantara-Hernandez, R. J.; Beltran, Y.; Centeno, C.; Cerqueda-Garcia, D.; Pi-Puig, T.; Castillo, F. S.

    2015-12-01

    Microbialites are the modern analogues of ancient microbial consortia. Their existence extends from the Archaean (~3500 mya) until present and their lithified structure evidences the capacity of microbial communities to mediate mineral precipitation. Living microbialites are a useful study model to test the mechanisms involved in carbonates and other minerals precipitation. Here, we studied the chemical composition, the biomass and the microbial structure of extant microbialites. All of these were found in Mexico, in water systems of different and characteristic ionic firms. An elemental analysis (C:N) of microbial biomass was performed and total P was determined. To explore the chemical composition of microbialites as a whole, X-ray diffraction analyses were performed over dry microbialites. While overall inorganic carbon content (carbonates) represented >70% of the living layer, a protocol of inorganic carbon elimination was performed for each sample resulting in organic matter contents between 8 and 16% among microbialites. Stoichiometric ratios of C:N:P in microbialite biomass were different among samples, and the possibility of P limitation was suggested mainly for karstic microbialites, N limitation was suggested for all samples and, more intensively, for soda system microbialites. A differential capacity for biomass allocation among microbialites was observed. Microbialites showed, along the biogeographic gradient, a diverse arrangement of microbial assemblages within the mineral matrix. While environmental factors such as pH and nitrate concentration were the factors that defined the general structure and diversity of these assemblages, we intend to test if the abundance of major ions and trace metals are also defining microbialite characteristics (such as microbial structure and biomass). This work contributes to define a baseline of the chemical nature of extant microbial consortia actively participating in mineral precipitation processes.

  20. Mineral-enhanced hydrothermal oligopeptide formation at the second time scale.

    PubMed

    Kawamura, Kunio; Takeya, Hitoshi; Kushibe, Takao; Koizumi, Yuka

    2011-06-01

    Accumulation of biopolymers should have been an essential step for the emergence of life on primitive Earth. However, experimental simulations for submarine hydrothermal vent systems in which high-temperature water spouts through minerals within a short time scale have not been attempted. Here, we show that enhancement of hydrothermal oligopeptide elongation by naturally occurring minerals was successfully verified for the first time by using a mineral-mediated hydrothermal flow reactor system (MMHF). MMHF consists of a narrow tubular reactor packed with mineral particles, and the enhancement or inhibitory activities of 10 types of naturally occurring minerals were successfully evaluated for an elongation reaction from (Ala)(4) to (Ala)(5) and higher oligopeptides in the absence of condensation reagents. It was unexpected that calcite and dolomite facilitated the elongation from (Ala)(4) to (Ala)(5) and higher oligopeptides with 28% yield at pH 7, while tourmaline, galena, apatite, mica, sphalerite, quartz, chalcopyrite, and pyrite did not show enhancement activities. These facts suggest the importance of carbonate minerals for the accumulation of peptide in primitive Earth environments. PMID:21671764

  1. Mineral-enhanced hydrothermal oligopeptide formation at the second time scale.

    PubMed

    Kawamura, Kunio; Takeya, Hitoshi; Kushibe, Takao; Koizumi, Yuka

    2011-06-01

    Accumulation of biopolymers should have been an essential step for the emergence of life on primitive Earth. However, experimental simulations for submarine hydrothermal vent systems in which high-temperature water spouts through minerals within a short time scale have not been attempted. Here, we show that enhancement of hydrothermal oligopeptide elongation by naturally occurring minerals was successfully verified for the first time by using a mineral-mediated hydrothermal flow reactor system (MMHF). MMHF consists of a narrow tubular reactor packed with mineral particles, and the enhancement or inhibitory activities of 10 types of naturally occurring minerals were successfully evaluated for an elongation reaction from (Ala)(4) to (Ala)(5) and higher oligopeptides in the absence of condensation reagents. It was unexpected that calcite and dolomite facilitated the elongation from (Ala)(4) to (Ala)(5) and higher oligopeptides with 28% yield at pH 7, while tourmaline, galena, apatite, mica, sphalerite, quartz, chalcopyrite, and pyrite did not show enhancement activities. These facts suggest the importance of carbonate minerals for the accumulation of peptide in primitive Earth environments.

  2. Large-Scale Processing of Carbon Nanotubes

    NASA Technical Reports Server (NTRS)

    Finn, John; Sridhar, K. R.; Meyyappan, M.; Arnold, James O. (Technical Monitor)

    1998-01-01

    Scale-up difficulties and high energy costs are two of the more important factors that limit the availability of various types of nanotube carbon. While several approaches are known for producing nanotube carbon, the high-powered reactors typically produce nanotubes at rates measured in only grams per hour and operate at temperatures in excess of 1000 C. These scale-up and energy challenges must be overcome before nanotube carbon can become practical for high-consumption structural and mechanical applications. This presentation examines the issues associated with using various nanotube production methods at larger scales, and discusses research being performed at NASA Ames Research Center on carbon nanotube reactor technology.

  3. Pore Scale Modeling of Mixing-Induced Carbonate Precipitation

    NASA Astrophysics Data System (ADS)

    Steefel, C.; Molins, S.; Shen, C.; Trebotich, D.

    2011-12-01

    Mixing of groundwaters of differing chemical composition can lead to precipitation of minerals, potentially modifying the transport and chemical properties of the subsurface materials. Carbonate minerals are particularly common secondary phases that form as a result of mixing, although in many instances their formation is also affected by a suite of complex dissolution and precipitation reactions that change the pH and alkalinity of groundwater. In the case of mixing, several distinct regimes are recognized, depending on the supersaturation generated by the mixing process. In the case where high degrees of supersaturation with respect to carbonate occur as a result of mixing (e.g., log Q/Keq > 1.5, where Q is the ion activity product and Keq is the equilibrium constant), homogeneous nucleation can generate reactive surface area for continued carbonate growth. In this case, no interaction between the mixing fluid and immobile solid phases is needed. In contrast, where supersaturation is more limited (log Q/Keq = 0.5 to 1.5), precipitation generally takes place via heterogeneous nucleation, in which case a templated mineral surface (normally carbonate) is required. Heterogeneous nucleation of carbonates is typically second order with respect to the supersaturation. At lower degrees of supersaturation (log Q/Keq < 0.5), precipitation takes place via crystal growth on discrete surface features of the carbonate mineral (e.g., via spiral growth) surface and shows a first order or quasi-first order dependence on supersaturation. Thus, the supersaturation induced by mixing largely controls the order of the reaction and the extent of interaction with pre-existing mineral surfaces in the subsurface. These in turn impact how the physical and chemical properties of the medium are modified by carbonate precipitation. We are investigating these carbonate precipitation regimes using pore scale reactive transport modeling based on Direct Numerical Simulation methods. Our

  4. Nucleation and growth of minerals: Atomic-, meso- and pore-scale perspectives

    NASA Astrophysics Data System (ADS)

    Stack, A. G.; Bracco, J. N.; Rother, G.; Anovitz, L.; Fernandez-martinez, A.; Waychunas, G.; Gale, J. D.; Raiteri, P.

    2012-12-01

    The ability to predict and control the nucleation and growth of minerals is important in a variety of applications such as disposal of spent nuclear fuel, scale formation during oil, gas and geothermal production, remediation of contaminants such as toxic metals and sequestration of carbon dioxide. Macroscopic net reaction rates and mineral/material morphologies all are ultimately driven by atomic-scale reactions on surfaces. While our ability to determine and detect atomic-scale processes has improved, significant challenges remain in relating these to macroscopic observables. The meso-scale offers us a potential ability to bridge these disparate time- and length-scales. In this talk, I will discuss our recent work to relate atomic-level reactions to macroscopic rates via the meso-scale on two common sparingly-soluble ionically-bonded salts: calcite (CaCO3) and barite (BaSO4),. First, I will discuss our efforts to use rare event theories (e.g., metadynamics, umbrella sampling, reactive flux) coupled to molecular dynamics simulations to determine the mechanisms and rates of mineral growth reactions that are too slow to simulate directly. Specifically I will discuss 'kink site nucleation' reactions, thought to be rate limiting under many conditions close to equilibrium during crystal growth. Second, I will discuss our efforts to infer the rates of attachment and detachment to these sites during from atomic force microscopy experiments of monomolecular step velocities as a function of saturation index and aqueous cation-to-anion ratio. I will conclude with studies of the nucleation of calcium carbonate in a synthetic porous media, controlled pore glass. Here I show that pore-scale processes and the interaction between substrate and solute can change not just rates, but in which pores precipitation preferentially occurs.

  5. Effects of carbon substrate lability on carbon mineralization dynamics of tropical peat

    NASA Astrophysics Data System (ADS)

    Jauhiainen, Jyrki; Silvennoinen, Hanna; Könönen, Mari; Limin, Suwido; Vasander, Harri

    2016-04-01

    Extensive draining at tropical ombrotrophic peatlands in Southeast Asia has made them global 'hot spots' for greenhouse gas emissions. Management practises and fires have led to changed substrate status, which affects microbial processes. Here, we present the first data on how management practises affect carbon (C) mineralization processes at these soils. We compared the carbon mineralization potentials of pristine forest soils to those of drained fire affected soils at various depths, with and without additional labile substrates (glucose, glutamate and NO3-N) and in oxic and anoxic conditions by dedicated ex situ experiments. Carbon mineralization (CO2 and CH4 production) rates were higher in the pristine site peat, which contains more labile carbon due to higher input via vegetation. Production rates decreased with depth together with decreasing availability of labile carbon. Consequently, the increase in production rates after labile substrate addition was relatively modest from pristine site as compared to the managed site and from the top layers as compared to deeper layers. Methanogenesis had little importance in total carbon mineralization. Adding labile C and N enhanced heterotrophic CO2 production more than the sole addition of N. Surprisingly, oxygen availability was not an ultimate requirement for substantial CO2 production rates, but anoxic respiration yielded comparable rates, especially at the pristine soils. Flooding of these sites will therefore reduce, but not completely cease, peat carbon loss. Reintroduced substantial vegetation and fertilization in degraded peatlands can enrich recalcitrant peat with simple C and N compounds and thus increase microbiological activity.

  6. Aerobic microbial mineralization of dichloroethene as sole carbon substrate

    USGS Publications Warehouse

    Bradley, P.M.; Chapelle, F.H.

    2000-01-01

    Microorganisms indigenous to the bed sediments of a black- water stream utilized 1,2-dichloroethene (1,2-DCE) as a sole carbon substrate for aerobic metabolism. Although no evidence of growth was observed in the minimal salts culture media used in this study, efficient aerobic microbial mineralization of 1,2-DCE as sole carbon substrate was maintained through three sequential transfers (107 final dilution) of the original environmental innoculum. These results indicate that 1,2-DCE can be utilized as a primary substrate to support microbial metabolism under aerobic conditions.Microorganisms indigenous to the bed sediments of a black-water stream utilized 1,2-dichloroethene (1,2-DCE) as a sole carbon substrate for aerobic metabolism. Although no evidence of growth was observed in the minimal salts culture media used in this study, efficient aerobic microbial mineralization of 1,2-DCE as sole carbon substrate was maintained through three sequential transfers (107 final dilution) of the original environmental innoculum. These results indicate that 1,2-DCE can be utilized as a primary substrate to support microbial metabolism under aerobic conditions.

  7. Pore scale heterogeneity in the mineral distribution and surface area of porous rocks

    NASA Astrophysics Data System (ADS)

    Lai, Peter; Moulton, Kevin; Krevor, Samuel

    2014-05-01

    There are long-standing challenges in characterizing reactive transport in porous media at scales larger than individual pores. This hampers the prediction of the field-scale impact of geochemical processes on fluid flow [1]. This is a source of uncertainty for carbon dioxide injection, which results in a reactive fluid-rock system, particularly in carbonate rock reservoirs. A potential cause is the inability of the continuum approach to incorporate the impact of heterogeneity in pore-scale reaction rates. This results in part from pore-scale heterogeneities in surface area of reactive minerals [2,3]. The objective of this study was to quantify heterogeneity in reactive surface and observe the extent of its non-normal character. In this study we describe our work in using micron-scale x-ray imaging and other spectroscopic techniques for the purpose of describing the statistical distribution of reactive surface area within a porous medium, and identifying specific mineral phases and their distribution in 3-dimensions. Using in-house image processing techniques and auxilary charactersation with thin section, electron microscope and spectroscopic techniques we quantified the surface area of each mineral phase in the x-ray CT images. This quantification was validated against nitrogen BET surface area and backscattered electron imaging measurements of the CT-imaged samples. Distributions in reactive surface area for each mineral phase were constructed by calculating surface areas in thousands of randomly selected subvolume images of the total sample, each normalized to the pore volume in that image. In all samples, there is little correlation between the reactive surface area fraction and the volumetric fraction of a mineral in a bulk rock. Berea sandstone was far less heterogeneous and has a characteristic pore size at which a surface area distribution may be used to quantify heterogeneity. In carbonates, heterogeneity is more complex and surface area must be

  8. Numerically Simulating Carbonate Mineralization of Basalt with Injection of Carbon Dioxide into Deep Saline Formations

    SciTech Connect

    White, Mark D.; McGrail, B. Peter; Schaef, Herbert T.; Bacon, Diana H.

    2006-07-08

    The principal mechanisms for the geologic sequestration of carbon dioxide in deep saline formations include geological structural trapping, hydrological entrapment of nonwetting fluids, aqueous phase dissolution and ionization, and geochemical sorption and mineralization. In sedimentary saline formations the dominant mechanisms are structural and dissolution trapping, with moderate to weak contributions from hydrological and geochemical trapping; where, hydrological trapping occurs during the imbibition of aqueous solution into pore spaces occupied by gaseous carbon dioxide, and geochemical trapping is controlled by generally slow reaction kinetics. In addition to being globally abundant and vast, deep basaltic lava formations offer mineralization kinetics that make geochemical trapping a dominate mechanism for trapping carbon dioxide in these formations. For several decades the United States Department of Energy has been investigating Columbia River basalt in the Pacific Northwest as part of its environmental programs and options for natural gas storage. Recently this nonpotable and extensively characterized basalt formation is being reconsidered as a potential reservoir for geologic sequestration of carbon dioxide. The reservoir has an estimated storage capacity of 100 giga tonnes of carbon dioxide and comprises layered basalt flows with sublayering that generally alternates between low permeability massive and high permeability breccia. Chemical analysis of the formation shows 10 wt% Fe, primarily in the +2 valence. The mineralization reaction that makes basalt formations attractive for carbon dioxide sequestration is that of calcium, magnesium, and iron silicates reacting with dissolved carbon dioxide, producing carbonate minerals and amorphous quartz. Preliminary estimates of the kinetics of the silicate-to-carbonate reactions have been determined experimentally and this research is continuing to determine effects of temperature, pressure, rock composition and

  9. Manganese carbonate mineralization in the Molango district, Mexico

    USGS Publications Warehouse

    Okita, P.M.

    1992-01-01

    Mn carbonate mineralization is hosted by a finely laminated Upper Jurassic marine sedimentary sequence that forms the base of the Chipoco facies of the Taman Formation (Kimmeridgian). The carbonate ore bed consists of fine-grained rhodochrosite and dispersed organic matter, magnetite, and maghemite but generally only trace quantities of pyrite. Fine laminations and clotted textures suggest deposition in a restricted marine environment. Several geologic and geochemical processes resulted in the formation of Mn carbonate by the early diagenetic reduction of Mn oxides through the oxidation of organic matter and iron sulfide. The ultimate source of the manganese is uncertain but may have been fluvial-sediment loads or hydrothermal activity associated with the rifting of the Gulf of Mexico. -from Author

  10. Soil Organic Carbon Loss: An Overlooked Factor in the Carbon Sequestration Potential of Enhanced Mineral Weathering

    NASA Astrophysics Data System (ADS)

    Dietzen, Christiana; Harrison, Robert

    2016-04-01

    Weathering of silicate minerals regulates the global carbon cycle on geologic timescales. Several authors have proposed that applying finely ground silicate minerals to soils, where organic acids would enhance the rate of weathering, could increase carbon uptake and mitigate anthropogenic CO2 emissions. Silicate minerals such as olivine could replace lime, which is commonly used to remediate soil acidification, thereby sequestering CO2 while achieving the same increase in soil pH. However, the effect of adding this material on soil organic matter, the largest terrestrial pool of carbon, has yet to be considered. Microbial biomass and respiration have been observed to increase with decreasing acidity, but it is unclear how long the effect lasts. If the addition of silicate minerals promotes the loss of soil organic carbon through decomposition, it could significantly reduce the efficiency of this process or even create a net carbon source. However, it is possible that this initial flush of microbial activity may be compensated for by additional organic matter inputs to soil pools due to increases in plant productivity under less acidic conditions. This study aimed to examine the effects of olivine amendments on soil CO2 flux. A liming treatment representative of typical agricultural practices was also included for comparison. Samples from two highly acidic soils were split into groups amended with olivine or lime and a control group. These samples were incubated at 22°C and constant soil moisture in jars with airtight septa lids. Gas samples were extracted periodically over the course of 2 months and change in headspace CO2 concentration was determined. The effects of enhanced mineral weathering on soil organic matter have yet to be addressed by those promoting this method of carbon sequestration. This project provides the first data on the potential effects of enhanced mineral weathering in the soil environment on soil organic carbon pools.

  11. High-temperature carbonate minerals in the Stillwater Complex, Montana, USA

    NASA Astrophysics Data System (ADS)

    Aird, Hannah M.; Boudreau, Alan E.

    2013-10-01

    High-temperature carbonate minerals have been observed in association with sulfide minerals below the platiniferous Johns-Manville (J-M) reef of the Stillwater Complex in a stratigraphic section that has been previously shown to be characterized by unusually Cl-rich apatite. The carbonate assemblage consists of dolomite with exsolved calcite in contact with sulfide minerals: chalcopyrite and pyrrhotite in the Peridotite Zone; and pyrrhotite with pentlandite, pyrite and chalcopyrite in Gabbronorite Zone I of the Lower Banded Series. A reaction rim surrounds the carbonate-sulfide assemblages, showing an alteration of the host orthopyroxene to a more calcium-enriched, Fe-depleted pyroxene. The calcite-dolomite geothermometer yields a minimum formation temperature as high as 950 °C for the unmixed assemblages. Iron and manganese concentrations exceed the range seen in carbonatite and mantle xenolith carbonates and are distinctly different from the nearly pure end-member carbonates associated with greenschist-grade (and lower) assemblages (e.g., carbonate veins in serpentinite) that occur locally throughout the complex. The association of high-temperature carbonates with sulfides beneath the J-M reef supports the hydromagmatic theory which involves a late-stage chloride-carbonate fluid percolating upwards, dissolving PGE and sulfides and redepositing them at a higher stratigraphic level. Characterization of the processes which form strategically important metal deposits, such as the J-M reef of the Stillwater Complex and the analogous Merensky reef of the Bushveld Complex in South Africa, could potentially lead to better exploration models and, more broadly, a deeper understanding of the cooling and compositional evolution of large bodies of ultramafic and mafic magma and of carbonatites, on both a local and a regional scale.

  12. Carbon-Mineral Interactions along an Earthworm Invasion Gradient

    NASA Astrophysics Data System (ADS)

    Lyttle, A.; Yoo, K.; Aufdenkampe, A. K.; Hale, C.; Sebestyen, S. D.

    2010-12-01

    We broadly agree that the interactions of organic matter and minerals contribute to soils’ capacity to store carbon. Such interactions may be controlled by the processes that determine the availability of organic matter and minerals and their physical contacts. One of these processes is bioturbation, and earthworms are the best known organisms that physically mix soils. We are studying carbon mineral interactions along an approximately 200 meter long earthworm invasion transect in a hardwood forest in northern Minnesota. This transect extends from the soils where earthworms are absent to the soils that have been invaded by earthworms for ~30-40 years. Pre-invasion soils have approximately 5 cm thick litter layer, thin (~5 cm) A horizon, silt rich E horizon, and clay-rich Bt horizons. The A and E horizons formed from aeolian deposits, while the clay-rich Bt horizons developed from glacial till. With the advent of earthworm invasion, the litter layer disappears, and the A horizon thickens at the expense of the E horizons. Carbon and nitrogen concentrations in the A and E horizons significantly increased with the advent of earthworm invasion. Simultaneously, minerals’ capacities to complex the organic matter appear to be greater in the soils with active earthworm populations. Based on the data from the two end member soils along the transect, minerals’ specific surface area in the A and E horizons are larger in the earthworm invaded soil than in the pre-invasion soil. Additionally, earthworm invasion rapidly (within < 5 yrs) turned A horizons materials from single grain to strong medium granular structure. Second, significantly greater amounts of Fe oxides and organically-complexed Fe are present in the earthworm invaded soil. While the amounts of organic matter and the minerals’ capacity to complex carbon increase with earthworm invasion, they are also more vigorously mixed. The depth profiles of 210Pb activities from the two end member soils show

  13. Pore scale heterogeneity in the mineral distribution and reactive surface area of rocks

    NASA Astrophysics Data System (ADS)

    Lai, P. E.; Krevor, S. C.

    2013-12-01

    There are long-standing challenges in characterizing reactive transport in porous media at scales larger than individual pores. This hampers the prediction of the field-scale impact of geochemical processes on fluid flow [1]. This is a source of uncertainty for CO2 injection, which results in a reactive fluid-rock system, particularly in carbonate rock reservoirs. A potential cause is the inability of the continuum approach to incorporate the impact of heterogeneity in pore-scale reaction rates. This results in part from pore-scale heterogeneities in surface area of reactive minerals [2,3]. In this study we have created μm resolution 3D images of 3 sandstone and 4 carbonate rocks using x-ray microtomography. Using in-house image processing techniques and auxiliary characterisation with thin section, electron microscope and spectroscopic techniques we quantified the surface area of each mineral phase in the x-ray CT images. This quantification was validated against N2 BET surface area and He porosity measurements of the imaged samples. Distributions in reactive surface area for each mineral phase were constructed by calculating surface areas in thousands of randomly selected subvolume images of the total sample, each normalized to the pore volume in that image. In all samples, there is little correlation between the reactive surface area fraction and the volumetric fraction of a mineral in a bulk rock. Berea sandstone was far less heterogeneous and has a characteristic pore size at which a surface area distribution may be used to quantify heterogeneity. In carbonates, heterogeneity is more complex and surface area must be characterized at multiple length scales for an accurate description of reactive transport. [1] Maher, Steefel, Depaolo and Vianni (2006) Geochimica et Cosmochimica Acta, 70, 337-363 [2] Landrot, Ajo-Franklin, Yang, Cabrini and Steefel (2012) Chemical Geology 318-319, 113-125 [3] Li, Peters and Celia (2007) American Journal of Science 307, 1146

  14. Rates of mineral dissolution and carbonation in peridotite and basalt

    NASA Astrophysics Data System (ADS)

    Kelemen, P. B.; Matter, J. M.

    2009-12-01

    We study natural rates and processes of mineral carbonation in peridotite (olivine-rich rock) in mantle rocks exposed to weathering in northern Oman to learn effective mechanisms from natural processes, and seek ways to accelerate them to achieve significant CO2 capture and storage via mineral carbonation at the lowest possible cost. In our first paper (1), we fit data on mantle olivine carbonation from the DOE Albany Research Center (2,3, ARC). These data, and data from Arizona State University (4, ASU) suggest that a peridotite rock volume heated to 185°C and infused with H2O+CO2 at PCO2 > 75 bars could consume ~ 1 ton CO2 per cubic meter of rock per year. Because it is more abundant than peridotite, other workers focus on carbonation of the most common type of lava on Earth, basalt, whose main mineral constituent is generally labradorite, part of the plagioclase feldspar solid solution series. Our intuition is that labradorite carbonation is much slower than mantle olivine carbonation. To quantify this, we compiled data on dissolution of mantle olivine, labradorite, crystalline basalt, and basaltic glass in aqueous fluids, as well as data on mantle olivine carbonation. The dissolution data are calibrated as a function of surface area (i.e., grain size and shape) and pH, as well as temperature, whereas most of the ARC and ASU experiments were done at a single pH and grain size. Thus, for comparison, we calculated dissolution rates for 70 micron spheres at pH 8, close to the ARC and ASU experimental conditions. At these conditions, olivine carbonation observed by ARC and ASU is 100 to 1000 times faster than labradorite and crystalline basalt, and faster than conventionally measured olivine dissolution rates. The ARC and ASU experiments were different from conventional dissolution experiments in several ways that could lead to an enhancement in olivine reaction rates: (a) they may have lower a(Mg) in fluid due to solid MgCO3 (magnesite) precipitation, (b) they

  15. Modeling reaction-driven cracking during mineral carbonation in peridotite for CO2 sequestration

    NASA Astrophysics Data System (ADS)

    Paukert, A. N.; Sonnenthal, E. L.; Matter, J.; Kelemen, P. B.

    2013-12-01

    In situ mineral carbonation in mantle peridotite has been proposed as a mechanism for long-term, environmentally benign CO2 sequestration1,2. This process converts peridotite and CO2 to carbonate minerals, like magnesite, in the subsurface, providing permanent and safe storage of the CO2. The volume that can be sequestered in this manner is an open question as peridotite carbonation involves a positive volume change and peridotite aquifers have limited porosity and permeability to accommodate the addition of solid volume. Conversion of peridotite to magnesite results in a volume increase of ~44%, which will fill the existing pore space and could limit the extent of carbonation by reducing porosity and permeability, clogging fluid flow paths, and armoring the reactive surface area. Alternatively, the force of crystallization and changes in fluid pressure from carbonation could act as driving forces for mechanical deformation and fracture propagation within the peridotite, creating new porosity, permeability, and reactive surface area, allowing carbonation to continue3. Natural examples of peridotite that have been entirely converted to magnesite suggest that reactive cracking from mineral carbonation is possible given the right conditions, such as elevated temperature and pCO2 2. Results will be presented from a reactive transport model that has been developed for peridotite carbonation using TOUGHREACT v.24. This model evaluates water and CO2 flow through peridotite fractured at different scales using a multiple continuum mesh. The effect of fluid flow, chemical reactions, and porosity and permeability feedbacks on carbonation rate and extent are explored, as is the effect of temperature. Peridotite carbonation is exothermic, so the release of heat of reaction could be balanced with the fluid injection temperature to maintain the 185oC conditions that facilitate the fastest carbonation rate2. The effect of fluid temperature and flow rate on the rate of carbonation

  16. Real Time Pore Structure Evolution during Olivine Mineral Carbonation

    NASA Astrophysics Data System (ADS)

    Zhu, W.; Fusseis, F.; Lisabeth, H. P.; Xiao, X.

    2014-12-01

    Aqueous carbonation of ultramafic rocks has been proposed as a promising method for long-term, secure sequestration of carbon dioxide. While chemical kinetics data indicate that carbonation reaction in olivine is one of the fastest among the mg-bearing minerals, in practice, the factors that limit the extent and rate of carbonation in ultramafic rocks are fluid supply and flux. On the one hand, reaction products could produce passivating layer that prohibits further reactions. On the other hand, the increases in solid volume during carbonation could lead to cracking and create new fluid paths. Whether carbonation in ultramafic rocks is self-limiting or self-sustaining has been hotly debated. Experimental evidence of precipitation of reaction products during olivine carbonation was reported. To date, reaction-driven cracking has not been observed. In this paper, we present the first real-time pore structure evolution data using the x-ray synchrotron microtomography. Sodium bicarbonate (NaHCO3) solution was injected into porous olivine aggregates and in-situ pore structure change during olivine carbonation at a constant confining pressure (12 MPa) and a temperature of 200oC was captured at 30 min. interval for ~160 hours. Shortly after the experiment started, filling-in of the existing pores by precipitation of reaction products was visible. The size of the in-fills kept increasing as reactions continued. After ~48 hours, cracking around the in-fill materials became visible. After ~60 hours, these cracks started to show a clear polygonal pattern, similar to the crack patterns usually seen on the surface of drying mud. After ~72 hours, some of the cracks coalesced into large fractures that cut-through the olivine aggregates. New fractures continued to develop and at the end of the experiment, the sample was completely disintegrated by these fractures. We also conducted nanotomography experiments on a sub-volume of the reacted olivine aggregate. Orthogonal sets of

  17. Active Layer Soil Carbon and Nutrient Mineralization, Barrow, Alaska, 2012

    DOE Data Explorer

    Stan D. Wullschleger; Holly M. Vander Stel; Colleen Iversen; Victoria L. Sloan; Richard J. Norby; Mallory P. Ladd; Jason K. Keller; Ariane Jong; Joanne Childs; Deanne J. Brice

    2015-10-29

    This data set consists of bulk soil characteristics as well as carbon and nutrient mineralization rates of active layer soils manually collected from the field in August, 2012, frozen, and then thawed and incubated across a range of temperatures in the laboratory for 28 day periods in 2013-2015. The soils were collected from four replicate polygons in each of the four Areas (A, B, C, and D) of Intensive Site 1 at the Next-Generation Ecosystem Experiments (NGEE) Arctic site near Barrow, Alaska. Soil samples were coincident with the established Vegetation Plots that are located in center, edge, and trough microtopography in each polygon. Data included are 1) bulk soil characteristics including carbon, nitrogen, gravimetric water content, bulk density, and pH in 5-cm depth increments and also by soil horizon, 2) carbon, nitrogen, and phosphorus mineralization rates for soil horizons incubated aerobically (and in one case both aerobically and anaerobically) for 28 days at temperatures that included 2, 4, 8, and 12 degrees C. Additional soil and incubation data are forthcoming. They will be available when published as part of another paper that includes additional replicate analyses.

  18. Scaling minerals from deep-seated granitic geothermal reservoir

    NASA Astrophysics Data System (ADS)

    Yanagisawa, Norio

    2016-04-01

    To promote geothermal energy use and sustainable production, the information of scaling situation from deep-seated geothermal reservoir is important. In Japan, at the Kakkonda geothermal field, Iwate prefecture, north-eastern of Japan, there is 80MW geothermal power plant using about 300 degree C fluid from the reservoir at the boundary between Quaternary Kakkonda granite and Pre-Tertiary formations about 3km depth and more deep-seated reservoir survey was carried out by NEDO. Then, to understand the mechanism of deep-seated reservoir, we survey the metal sulphide minerals deposited at production wellhead and pipeline and compare with the brine And the brine of WD-1a at 3.7km depth, into Quaternary Kakkonda granite rock. In Kakkonda geothermal system, the scales are classified into two types based on sulphide mineralogy, which are Pb-Zn rich type and Cu rich type. Pb-Zn rich scales, for example galena (PbS) and Sphalerite (ZnS), are found in Well-19 located at the marginal part of the Kakkonda granite And Cu-rich scales, for example chalcocite (Cu2S), loellingite (FeAs2) and native antimony (Sb), are found in Well-13, located at the central part of the Kakkonda granite. And the brine of WD-1a at 3.7km depth about 500 degree C, into Quaternary Kakkonda granite rock near Well-19 is rich in Pb and Zn and similar composition as the Well-19 scale. Therefore, deep reservoir of Kakkonda field evolves with mixing the fluid of shallow reservoir and the brine of occurred in the Quaternary Kakkonda granite. Then, the existence of both Pb-Zn rich scale and Cu rich scale is a characteristic feature of Kakkonda geothermal and this fact suggest to have similar zoning as found in Porphyry Copper Zoning. On progress of production the fluids from deep reservoir continue to be suffered by the fluid of shallow reservoir and meteoritic water. With temperature of production well decreasing and chemical composition changed, silica precipitation decreased and the metal sulfide mineral

  19. Research status on the sequestration of carbon dioxide by direct aqueous mineral carbonation

    SciTech Connect

    O'Connor, William K.; Dahlin, David C.; Nilsen, David N.; Gerdemann, Stephen J.; Rush, Gilbert E.; Walters, Richard P.; Turner, Paul C.

    2001-01-01

    Direct aqueous mineral carbonation has been investigated as a process to convert gaseous CO2 into a geologically stable, solid final form. The process utilizes a solution of distilled water, or sodium bicarbonate (NaHCO3), sodium chloride (NaCl), and water, mixed with a mineral reactant, such as olivine (Mg2SiO4) or serpentine [Mg3Si2O5(OH)4]. Carbon dioxide is dissolved into this slurry, by diffusion through the surface and gas dispersion within the aqueous phase. The process includes dissolution of the mineral and precipitation of magnesium carbonate (MgCO3) in a single unit operation. Mineral reactivity has been increased by pretreatment of the minerals. Thermal activation of serpentine can be achieved by heat pretreatment at 630 C. Carbonation of the thermally activated serpentine, using the bicarbonate-bearing solution, at T=155 C, PCO2=185 atm, and 15% solids, achieved 78% stoichiometric conversion of the silicate to the carbonate in 30 minutes. Recent studies have investigated mechanical activation as an alternative to thermal treatment. The addition of a high intensity attrition grinding step to the size reduction circuit successfully activated both serpentine and olivine. Over 80% stoichiometric conversion of the mechanically activated olivine was achieved in 60 minutes, using the bicarbonate solution at T=185 C, PCO2=150 atm, and 15% solids. Significant carbonation of the mechanically activated minerals, at up to 66% stoichiometric conversion, has also been achieved at ambient temperature (25 C) and PCO2 ={approx}10 atm.

  20. Scale criticality in estimating ecosystem carbon dynamics.

    PubMed

    Zhao, Shuqing; Liu, Shuguang

    2014-07-01

    Scaling is central to ecology and Earth system sciences. However, the importance of scale (i.e. resolution and extent) for understanding carbon dynamics across scales is poorly understood and quantified. We simulated carbon dynamics under a wide range of combinations of resolution (nine spatial resolutions of 250 m, 500 m, 1 km, 2 km, 5 km, 10 km, 20 km, 50 km, and 100 km) and extent (57 geospatial extents ranging from 108 to 1 247 034 km(2) ) in the southeastern United States to explore the existence of scale dependence of the simulated regional carbon balance. Results clearly show the existence of a critical threshold resolution for estimating carbon sequestration within a given extent and an error limit. Furthermore, an invariant power law scaling relationship was found between the critical resolution and the spatial extent as the critical resolution is proportional to A(n) (n is a constant, and A is the extent). Scale criticality and the power law relationship might be driven by the power law probability distributions of land surface and ecological quantities including disturbances at landscape to regional scales. The current overwhelming practices without considering scale criticality might have largely contributed to difficulties in balancing carbon budgets at regional and global scales. PMID:24323616

  1. Carbon Dioxide Sequestration by Direct Mineral Carbonation: Results from Recent Studies and Current Status

    SciTech Connect

    O'Connor, William K.; Dahlin, David C.; Nilsen, David N.; Rush, G.E.; Walters, Richard P.; Turner, Paul C.

    2001-01-01

    Direct mineral carbonation has been investigated as a process to convert gaseous CO2 into a geologically stable, solid final form. The process utilizes a solution of sodium bicarbonate (NaHCO3), sodium chloride (NaCl), and water, mixed with a mineral reactant, such as olivine (Mg2SiO4) or serpentine [Mg3Si2O5(OH)4]. Carbon dioxide is dissolved into this slurry, by diffusion through the surface and gas dispersion within the aqueous phase. The process includes dissolution of the mineral and precipitation of magnesium carbonate (MgCO3) in a single unit operation. Optimum results have been achieved using heat pretreated serpentine feed material, with a surface area of roughly 19 m2 per gram, and high partial pressure of CO2 (PCO2). Specific conditions include: 155?C; PCO2=185 atm; 15% solids. Under these conditions, 78% stoichiometric conversion of the silicate to the carbonate was achieved in 30 minutes. Studies suggest that the mineral dissolution rate is primarily surface controlled, while the carbonate precipitation rate is primarily dependent on the bicarbonate concentration of the slurry. Current studies include further examination of the reaction pathways, and an evaluation of the resource potential for the magnesium silicate reactant, particularly olivine. Additional studies include the examination of various pretreatment options, the development of a continuous flow reactor, and an evaluation of the economic feasibility of the process.

  2. Minerals

    MedlinePlus

    Minerals are important for your body to stay healthy. Your body uses minerals for many different jobs, including building bones, making ... regulating your heartbeat. There are two kinds of minerals: macrominerals and trace minerals. Macrominerals are minerals your ...

  3. Carbonation of Artificial Silicate Minerals in Soils: Passive Removal of Atmospheric CO2

    NASA Astrophysics Data System (ADS)

    Washbourne, C.; Renforth, P.; Manning, D. A.

    2010-12-01

    Sequestration of CO2 in global soils is a widely recognised phenomenon, which is amenable to an environmental engineering approach. It is proposed that the use of direct soil engineering, promoting CO2 sequestration by accelerating the activity of reactive mineral substrates, has the potential to harness the significant carbon turnover of the global pedologic system (75 x 10^15 gC/yr [1]) [2][3][4]. Estimates of C capture potential through this process are 100-1000 MTa-1. This study focuses on the ambient carbonation of high-Ca residues as agents of mineral CCS. A synergy of contemporary field observations is presented, alongside data acquired from laboratory testing (acid digestion, optical petrography, SEM, IRMS) of carbonated material recovered from urban brown-field and former industrial sites in north east England. It is demonstrated that urban soils may accumulate ~30 kg/m2 (300 T/ha) of carbon over 10 years as inorganic calcium carbonate, approximately twice the typical organic C content of rural soils, ~17.5 kg/m2 in the UK. Stable isotope data (δ13C and δ18O) confirm that over 90% of the carbon is derived from the atmosphere. Economic and mechanical constraints on experimental performance in industrial batch reactor settings have strongly influenced the contemporary view on the efficacy of mineral CCS for large-scale environmental application [5][6][7]. Effective, low-energy field-scale implementation of mineral CCS through soil engineering would counter many of these concerns. Proof of principle for carbon capture efficacy of artificial silicates in soil engineering has been demonstrated [4]; proof of field scale feasibility will be demonstrated though continuing empirical field observation, engineered field cell construction and laboratory investigation. [1] Schlesinger, W. H., et al. (2000), Biogeochemistry, Vol. 48: 7-20. [2] Lal, R. (2003), Critical Reviews in Plant Sciences, 22, pp. 151-184. [3] Manning, D. A. C., (2008), Mineralogical Magazine

  4. Mineral Influence on Microbial Survival During Carbon Sequestration

    NASA Astrophysics Data System (ADS)

    Santillan, E. U.; Shanahan, T. M.; Wolfe, W. W.; Bennett, P.

    2012-12-01

    CO2 sequestered in a deep saline aquifer will perturb subsurface biogeochemistry by acidifying the groundwater and accelerating mineral diagenesis. Subsurface microbial communities heavily influence geochemistry through their metabolic processes, such as with dissimilatory iron reducing bacteria (DIRB). However, CO2 also acts as a sterilant and will perturb these communities. We investigated the role of mineralogy and its effect on the survival of microbes at high PCO2 conditions using the model DIRB Shewanella oneidensis MR-1. Batch cultures of Shewanella were grown to stationary phase and exposed to high PCO2 using modified Parr reactors. Cell viability was then determined by plating cultures after exposure. Results indicate that at low PCO2 (2 bar), growth and iron reduction are decreased and cell death occurs within 1 hour when exposed to CO2 pressures of 10 bar or greater. Further, fatty acid analysis indicates microbial lipid degradation with C18 fatty acids being the slowest lipids to degrade. When cultures were grown in the presence of rocks or minerals representative of the deep subsurface such as carbonates and silicates and exposed to 25 bar CO2, survival lasted beyond 2 hours. The most effective protecting substratum was quartz sandstone, with cultures surviving beyond 8 hours of CO2 exposure. Scanning electron microscope images reveal biofilm formation on the mineral surfaces with copious amounts of extracellular polymeric substances (EPS) present. EPS from these biofilms acts as a reactive barrier to the CO2, slowing the penetration of CO2 into cells and resulting in increased survival. When biofilm cultures were grown with Al and As to simulate the release of toxic metals from minerals such as feldspars and clays, survival time decreased, indicating mineralogy may also enhance microbial death. Biofilms were then grown on iron-coated quartz sand to determine conversely what influence biofilms may have on mineral dissolution during CO2 perturbation

  5. Mineral carbonation for carbon sequestration in cement kiln dust from waste piles.

    PubMed

    Huntzinger, Deborah N; Gierke, John S; Sutter, Lawrence L; Kawatra, S Komar; Eisele, Timothy C

    2009-08-30

    Alkaline earth metals, such as calcium and magnesium oxides, readily react with carbon dioxide (CO(2)) to produce stable carbonate minerals. Carbon sequestration through the formation of carbonate minerals is a potential means to reduce CO(2) emissions. Calcium-rich, industrial solid wastes and residues provide a potential source of highly reactive oxides, without the need for pre-processing. This paper presents the first study examining the feasibility of carbon sequestration in cement kiln dust (CKD), a byproduct generated during the manufacturing of cement. A series of column experiments were conducted on segments of intact core taken from landfilled CKD. Based on stoichiometry and measured consumption of CO(2) during the experiments, degrees of carbonation greater than 70% of the material's potential theoretical extent were achieved under ambient temperature and pressure conditions. The overall extent of carbonation/sequestration was greater in columns with lower water contents. The major sequestration product appears to be calcite; however, more detailed material characterization is need on pre- and post-carbonated samples to better elucidate carbonation pathways and products.

  6. Optimized carbonation of magnesium silicate mineral for CO2 storage.

    PubMed

    Eikeland, Espen; Blichfeld, Anders Bank; Tyrsted, Christoffer; Jensen, Anca; Iversen, Bo Brummerstedt

    2015-03-11

    The global ambition of reducing the carbon dioxide emission makes sequestration reactions attractive as an option of storing CO2. One promising environmentally benign technology is based on forming thermodynamically stable carbonated minerals, with the drawback that these reactions usually have low conversion rates. In this work, the carbonation reaction of Mg rich olivine, Mg2SiO4, under supercritical conditions has been studied. The reaction produces MgCO3 at elevated temperature and pressure, with the addition of NaHCO3 and NaCl to improve the reaction rates. A sequestration rate of 70% was achieved within 2 h, using olivine particles of sub-10 μm, whereas 100% conversion was achieved in 4 h. This is one of the fastest complete conversions for this reaction reported to date. The CO2 sequestration rate is found to be highly dependent on the applied temperature and pressure, as well as the addition of NaHCO3. In contrast, adding NaCl was found to have limited effect on the reaction rate. The roles of NaHCO3 and NaCl as catalysts are discussed and especially how their effect changes with increased olivine particle size. The products have been characterized by Rietveld refinement of powder X-ray diffraction, scanning electron microscopy (SEM), and energy-dispersive X-ray (EDX) spectroscopy revealing the formation of amorphous silica and micrometer-sized magnesium carbonate crystals.

  7. Optimized carbonation of magnesium silicate mineral for CO2 storage.

    PubMed

    Eikeland, Espen; Blichfeld, Anders Bank; Tyrsted, Christoffer; Jensen, Anca; Iversen, Bo Brummerstedt

    2015-03-11

    The global ambition of reducing the carbon dioxide emission makes sequestration reactions attractive as an option of storing CO2. One promising environmentally benign technology is based on forming thermodynamically stable carbonated minerals, with the drawback that these reactions usually have low conversion rates. In this work, the carbonation reaction of Mg rich olivine, Mg2SiO4, under supercritical conditions has been studied. The reaction produces MgCO3 at elevated temperature and pressure, with the addition of NaHCO3 and NaCl to improve the reaction rates. A sequestration rate of 70% was achieved within 2 h, using olivine particles of sub-10 μm, whereas 100% conversion was achieved in 4 h. This is one of the fastest complete conversions for this reaction reported to date. The CO2 sequestration rate is found to be highly dependent on the applied temperature and pressure, as well as the addition of NaHCO3. In contrast, adding NaCl was found to have limited effect on the reaction rate. The roles of NaHCO3 and NaCl as catalysts are discussed and especially how their effect changes with increased olivine particle size. The products have been characterized by Rietveld refinement of powder X-ray diffraction, scanning electron microscopy (SEM), and energy-dispersive X-ray (EDX) spectroscopy revealing the formation of amorphous silica and micrometer-sized magnesium carbonate crystals. PMID:25688577

  8. Simultaneous inhibition of carbon and nitrogen mineralization in a forest soil by simulated acid precipitation

    SciTech Connect

    Klein, T.M.; Novick, N.J.; Kreitinger, J.P.; Alexander, M.

    1984-06-01

    One method to simulate the long-term exposure of soil to acid rain involves the addition of single doses of concentrated acid. The inhibition of carbon mineralization accompanied by a stimulation of nitrogen mineralization may result from this severe, unnatural treatment. The present study was designed to determine whether the inhibition of carbon mineralization and the accompanying enhanced nitrogen mineralization would occur when soils are treated with more dilute acid for long periods of time, as takes place in nature.

  9. Experimental Inhibition of Carbonate Mineral Precipitation by Sulfur Dioxide: Implications for Early Mars

    NASA Astrophysics Data System (ADS)

    Halevy, I.; Schrag, D. P.

    2009-12-01

    Sulfur dioxide (SO2) is abundant in terrestrial volcanic emissions and was likely at least as abundant in early martian emissions. Recent photochemical studies indicate that during episodes of vigorous volcanic activity, the atmospheric lifetime of SO2 may have been sufficiently long for it to have helped maintain liquid water on the surface of Mars and perhaps to have regulated the climate through a negative feedback between the atmospheric abundance of SO2 and the rate of chemical weathering of silicate minerals. Here we show experimentally, that atmospheric SO2 concentrations three orders of magnitude lower than those required for it to have been of climatic importance would have had a major impact on the aqueous chemistry at the planet's surface and the precipitated mineral assemblage. Specifically, at near-neutral and even mildly alkaline pH, part-per-billion (ppb) concentrations of SO2 prevent the formation of calcium carbonate in favour of hannebachite - a hydrated calcium sulfite. Based on the results of recent photochemical studies, a volcanic outgassing flux ~300 times smaller than the modern terrestrial flux would have been enough to maintain such atmospheric concentrations. This implies that almost any period of active volcanism would have given rise to conditions under which carbonate precipitation is prevented at near-neutral pH. In the presence of ferrous iron, green rust, a possible precursor to phyllosilicate minerals, co-precipitates with hannebachite. This provides a possible explanation for the presence of phyllosilicates on early Noachian surfaces in the apparent absence of outcrop-scale carbonates. Finally, oxidation of the mineral assemblage precipitated in the experiments produces sulfates, iron oxides and acidity, consistent with observed mineral assemblages and with evidence for acid-sulfate dominated environments on late Noachian-early Hesperian surfaces.

  10. Co-precipitation of phosphate and carbonate minerals: geological and ecological implications

    NASA Astrophysics Data System (ADS)

    Sanchez-Román, Monica; McKenzie, Judith; Vasconcelos, Crisogono

    2015-04-01

    Microorganisms play an important role in natural environments by controlling the metal cations (e.g., Ca2+, Mg2+, Fe2+) and the anions (CO32-, NH4+, PO43-) that precipitate as biominerals (e.g., carbonates, phosphates). In contrast to phosphate minerals, precipitation of carbonate minerals by bacteria has been widely studied in culture experiments and in natural environments. Moreover, studies of sedimentary phosphate minerals and their geological and ecological implications are rare. Nevertheless, phosphate minerals frequently co-precipitate with carbonates in culture experiments and in natural systems. In the present work, we investigate how microorganisms control the mineralogy and geochemistry of phosphate and carbonate minerals. For this, culture experiments were performed to study the co-precipitation of phosphate and carbonate minerals using aerobic heterotrophic bacteria at sedimentary Earth's surface conditions. Ca-Mg carbonate (dolomite, Mg-calcite) and/or Mg-carbonate (hydromagnesite) precipitated with Mg-phosphate (struvite). In most of the cultures, phosphate was the dominant mineral phase found in the bacterial precipitates and carbonates precipitated after phosphate phases. Notably, in all the cultures, we found a mixture of phosphate and carbonate minerals. This study shines new light into the microbial diagenetic processes involved in the co-precipitation of phosphate and carbonate minerals and links the P and C cycles.

  11. Carbonate Mineral Assemblages as Inclusions in Yakutian Diamonds: TEM Verifications

    NASA Astrophysics Data System (ADS)

    Logvinova, A. M.; Wirth, R.; Sobolev, N. V.; Taylor, L. A.

    2014-12-01

    Carbonate mineral inclusions are quite rare in diamonds from the upper mantle, but are evidence for a carbonate abundance in the mantle. It is believed that such carbonatitic inclusions originated from high-density fluids (HDFs) that were enclosed in diamond during its growth. Using TEM and EPMA, several kinds of carbonate inclusions have been identified in Yakutian diamonds : aragonite, dolomite, magnesite, Ba-, Sr-, and Fe-rich carbonates. Most of them are represented by multi-phase inclusions of various chemically distinct carbonates, rich in Ca, Mg, and K and associated with minor amounts of silicate, oxide, saline, and volatile phases. Volatiles, leaving some porosity, played a significant role in the diamond growth. A single crystal of aragonite (60μm) is herein reported for the first time. This inclusion is located in the center of a diamond from the Komsomolskaya pipe. Careful CL imaging reveals the total absence of cracks around the aragonite inclusion - i.e., closed system. This inclusion has been identified by X-ray diffraction and microprobe analysis. At temperatures above 1000 0C, aragonite is only stable at high pressures of 5-6 GPa. Inside this aragonite, we observed nanocrystalline inclusions of titanite, Ni-rich sulfide, magnetite, water-bearing Mg-silicate, and fluid bubbles. Dolomite is common in carbonate multi-phase inclusions in diamonds from the Internatsionalnaya, Yubileinaya, and Udachnaya kimberlite pipes. Alluvial diamonds of the northeastern Siberian Platform are divided into two groups based on the composition of HDFs: 1) Mg-rich multi-phase inclusions (60% magnesite + dolomite + Fe-spinel + Ti-silicate + fluid bubbles); and 2) Ca-rich multi-phase inclusions (Ca,Ba-, Ca,Sr-, Ca,Fe-carbonates + Ti-silicate + Ba-apatite + fluid bubbles). High-density fluids also contain K. Volatiles in the fluid bubbles are represented by water, Cl, F, S, CO2, CH4, and heavy hydrocarbons. Origin of the second group of HDFs may be related to the non

  12. Reaction of CO2 and Carbonate Mineral in Seawater for Mitigation of CO2 and Ocean Acidity

    NASA Astrophysics Data System (ADS)

    Rau, G. H.

    2010-12-01

    A lab-scale seawater/mineral carbonate gas scrubber was found to remove up to 97% of CO2 in a simulated flue gas stream at ambient temperature and pressure, with a large fraction of this carbon ultimately converted to dissolved calcium bicarbonate. Contrary to predictions based on classical carbonate chemistry, up to 85% of the captured carbon was retained in solution, i.e., it did not degas or precipitate, even after full equilibration with air. This is because abiotic precipitation of CaCO3 from seawater is chemically inhibited up to dissolved concentrations approaching 20X supersaturation. Thus, above-ground CO2 hydration with seawater, reaction with mineral carbonate, and conversion to dissolved Ca(HCO3)2 may provide a relatively simple point-source CO2 capture and storage scheme at coastal locations. This approach is analogous to wet limestone scrubbing of flue gas that is commonly used for SO2 removal. Such low-tech CO2 mitigation could be especially relevant for retrofitting to existing coastal power plants and for deployment in the developing world, the primary source of future CO2 emissions. An electrochemically powered version of the preceding has been demonstrated for air capture of CO2. In any case, the addition of the resulting alkaline solution to the ocean would benefit marine ecosystems that are currently challenged by acidification. This is indicated by the widespread use of miniature CO2/carbonate mineral/seawater reactors in saltwater aquaria to generate alkalinity for preserving or enhancing coral and shellfish growth. Large-scale applications would thus allow use of the planet’s largest saline reservoir, the ocean, to safely and effectively store anthropogenic carbon in a form other than molecular CO2 or carbonic acid. This approach in essence hastens Nature's own very effective but slow CO2 mitigation process; carbonate mineral weathering is a major consumer of excess atmospheric CO2 and ocean acidity on geologic times scales.

  13. Authigenic carbonate mineral formation in a latest Pleistocene palaeolake, Greece

    NASA Astrophysics Data System (ADS)

    Karageorgis, A. P.; Kanellopoulos, T. D.; Mavromatis, V.; Anagnostou, C. L.; Koutsopoulou, E.; Schmidt, M.; Pavlopoulos, K.; Tripsanas, E. K.; Hallberg, R. O.

    2012-12-01

    The Pagassitikos Gulf in Greece, is a semi-enclosed bay with maximum depth 102 m. According to the present-day bathymetric configuration and the sea level during the latest Pleistocene, the gulf would have been isolated from the open sea, forming a palaeolake since ~32 cal. ka B.P.. Initial visual inspection of sediment core B-4 (length, 258 cm), recovered from the deepest sector of the Pagassitikos Gulf, revealed evidence of a totally different depositional environment in the lowest part of the core: this contained light grey-coloured sediments, contrasting strongly with the overlain olive grey muds of the upper part. Multi-proxy analyses (mineralogy, geochemistry and scanning electron microscopy) showed the predominance of carbonate minerals (aragonite, dolomite and calcite) together with gypsum in the lowest part of the core. Additional evidence (δ18O and δ13C isotopes, and AMS 14C datings) suggest that carbonate mineral deposition can be attributed to autochthonous precipitation that took place in a saline palaeolake during the last glacial-early deglacial period. High δ18O values recorded in the lowest part of the core were associated with hypersaline and evaporative depositional environment. The most plausible explanation for the formation of the observed carbonate minerals directs to dolomite precipitation from hypersaline evaporating water bodies at low precipitation rates. Under varying weather conditions the precipitation of aragonite is favoured. Alternatively, high evaporation rates and gypsum formation, favouring an increase in Mg/Ca ratio, is proposed as a possible mechanism supporting authigenic dolomite precipitation. The lowest core sample to be AMS 14C dated provided an age of 19.53 cal. ka B.P. The palaeolake was presumably reconnected to the open sea at ~13.2 cal. ka B.P. during the last sea-level rise, marking the commencement of marine sedimentation characterised by the predominance of terrigenous aluminosilicates and fairly homogeneous

  14. ATOMIC-LEVEL IMAGING OF CO2 DISPOSAL AS A CARBONATE MINERAL: OPTIMIZING REACTION PROCESS DESIGN

    SciTech Connect

    M.J. McKelvy; R. Sharma; A.V.G. Chizmeshya; H. Bearat; R.W. Carpenter

    2000-08-01

    Fossil fuels, especially coal, can support the energy demands of the world for centuries to come, if the environmental problems associated with CO{sub 2} emissions can be overcome. Permanent and safe methods for CO{sub 2} capture and disposal/storage need to be developed. Mineralization of stationary-source CO{sub 2} emissions as carbonates can provide such safe capture and long-term sequestration. Mg-rich lamellar-hydroxide based minerals (e.g., brucite and serpentine) offer a class of widely available, low-cost materials, with intriguing mineral carbonation potential. Carbonation of such materials inherently involves dehydroxylation, which can disrupt the material down to the atomic level. As such, controlled dehydroxylation before and/or during carbonation may provide an important parameter for enhancing carbonation reaction processes. Mg(OH){sub 2} was chosen as the model material for investigating lamellar hydroxide mineral dehydroxylation/carbonation mechanisms due to (i) its structural and chemical simplicity, (ii) interest in Mg(OH){sub 2} gas-solid carbonation as a potentially cost-effective CO{sub 2} mineral sequestration process component, and (iii) its structural and chemical similarity to other lamellar-hydroxide-based minerals (e.g., serpentine-based minerals) whose carbonation reaction processes are being explored due to their low-cost CO{sub 2} sequestration potential. Fundamental understanding of the mechanisms that govern dehydroxylation/carbonation processes is essential for cost optimization of any lamellar-hydroxide-based mineral carbonation sequestration process.

  15. Normalization of stable isotope data for carbonate minerals: Implementation of IUPAC guidelines

    NASA Astrophysics Data System (ADS)

    Kim, Sang-Tae; Coplen, Tyler B.; Horita, Juske

    2015-06-01

    Carbonate minerals provide a rich source of geochemical information because their δ13C and δ18O values provide information about surface and subsurface Earth processes. However, a significant problem is that the same δ18O value is not reported for the identical carbonate sample when analyzed in different isotope laboratories in spite of the fact that the International Union of Pure and Applied Chemistry (IUPAC) has provided reporting guidelines for two decades. This issue arises because (1) the δ18O measurements are performed on CO2 evolved by reaction of carbonates with phosphoric acid, (2) the acid-liberated CO2 is isotopically fractionated (enriched in 18O) because it contains only two-thirds of the oxygen from the solid carbonate, (3) this oxygen isotopic fractionation factor is a function of mineralogy, temperature, concentration of the phosphoric acid, and δ18O value of water in the phosphoric acid, (4) researchers may use any one of an assortment of oxygen isotopic fractionation factors that have been published for various minerals at various reaction temperatures, and (5) it sometimes is not clear how one should calculate δ18OVPDB values on a scale normalized such that the δ18O value of SLAP reference water is -55.5 ‰ relative to VSMOW reference water.

  16. Ex-situ and in-situ mineral carbonation as a means to sequester carbon dioxide

    SciTech Connect

    Gerdemann, Stephen J.; Dahlin, David C.; O'Connor, William K.; Penner, Larry R.; Rush, G.E.

    2004-01-01

    The U. S. Department of Energy's Albany Research Center is investigating mineral carbonation as a method of sequestering CO2 from coal-fired-power plants. Magnesium-silicate minerals such as serpentine [Mg3Si2O5(OH)4] and olivine (Mg2SiO4) react with CO2 to produce magnesite (MgCO3), and the calcium-silicate mineral, wollastonite (CaSiO3), reacts to form calcite (CaCO3). It is possible to carry out these reactions either ex situ (above ground in a traditional chemical processing plant) or in situ (storage underground and subsequent reaction with the host rock to trap CO2 as carbonate minerals). For ex situ mineral carbonation to be economically attractive, the reaction must proceed quickly to near completion. The reaction rate is accelerated by raising the activity of CO2 in solution, heat (but not too much), reducing the particle size, high-intensity grinding to disrupt the crystal structure, and, in the case of serpentine, heat-treatment to remove the chemically bound water. All of these carry energy/economic penalties. An economic study illustrates the impact of mineral availability and process parameters on the cost of ex situ carbon sequestration. In situ carbonation offers economic advantages over ex situ processes, because no chemical plant is required. Knowledge gained from the ex situ work was applied to long-term experiments designed to simulate in situ CO2 storage conditions. The Columbia River Basalt Group (CRBG), a multi-layered basaltic lava formation, has potentially favorable mineralogy (up to 25% combined concentration of Ca, Fe2+, and Mg cations) for storage of CO2. However, more information about the interaction of CO2 with aquifers and the host rock is needed. Core samples from the CRBG, as well as samples of olivine, serpentine, and sandstone, were reacted in an autoclave for up to 2000 hours at elevated temperatures and pressures. Changes in core porosity, secondary mineralizations, and both solution and solid chemistry were measured.

  17. Carbon Mineralizability Determines Interactive Effects on Mineralization of Pyrogenic Organic Matter and Soil Organic Carbon

    SciTech Connect

    Whitman, Thea L.; Zhu, Zihua; Lehmann, Johannes C.

    2014-10-31

    Soil organic carbon (SOC) is a critical and active pool in the global C cycle, and the addition of pyrogenic organic matter (PyOM) has been shown to change SOC cycling, increasing or decreasing mineralization rates (often referred to as priming). We adjusted the amount of easily mineralizable C in the soil, through 1-day and 6-month pre-incubations, and in PyOM made from maple wood at 350°C, through extraction. We investigated the impact of these adjustments on C mineralization interactions, excluding pH and nutrient effects and minimizing physical effects. We found short-term increases (+20-30%) in SOC mineralization with PyOM additions in the soil pre-incubated for 6 months. Over the longer term, both the 6-month and 1-day pre-incubated soils experienced net ~10% decreases in SOC mineralization with PyOM additions. This was possibly due to stabilization of SOC on PyOM surfaces, suggested by nanoscale secondary ion mass spectrometry. Additionally, the duration of pre-incubation affected priming interactions, indicating that there may be no optimal pre-incubation time for SOC mineralization studies. We show conclusively that relative mineralizability of SOC in relation to PyOM-24 C is an important determinant of the effect of PyOM additions on SOC mineralization.

  18. Carbon mineralizability determines interactive effects on mineralization of pyrogenic organic matter and soil organic carbon.

    PubMed

    Whitman, Thea; Zhu, Zihua; Lehmann, Johannes

    2014-12-01

    Soil organic carbon (SOC) is a critical and active pool in the global C cycle, and the addition of pyrogenic organic matter (PyOM) has been shown to change SOC cycling, increasing or decreasing mineralization rates (often referred to as priming). We adjusted the amount of easily mineralizable C in the soil, through 1-day and 6-month preincubations, and in PyOM made from maple wood at 350 °C, through extraction. We investigated the impact of these adjustments on C mineralization interactions, excluding pH and nutrient effects and minimizing physical effects. We found short-term increases (+20-30%) in SOC mineralization with PyOM additions in the soil preincubated for 6 months. Over the longer term, both the 6-month and 1-day preincubated soils experienced net ∼10% decreases in SOC mineralization with PyOM additions. Additionally, the duration of preincubation affected interactions, indicating that there may be no optimal preincubation time for SOC mineralization studies. We show conclusively that mineralizability of SOC in relation to PyOM-C is an important determinant of the effect of PyOM additions on SOC mineralization. PMID:25361379

  19. Scaling of carbon erosion in Tore Supra

    NASA Astrophysics Data System (ADS)

    Marandet, Y.; Dachicourt, R.; Monier-Garbet, P.; Tsitrone, E.; Reiter, D.; Börner, P.; Beauté, A.; Delchambre, E.; Genesio, P.; Naiim-Habib, M.; Gunn, J. P.; Kubic, M.; Pégourié, B.; Aniel, T.; Brosset, C.; Colledani, G.; Corre, Y.; Gauthier, E.; Martinez, A.

    2011-08-01

    The scaling law for carbon erosion in Tore Supra previously established by Hogan et al. [1] (ΦC(C/s) = 5 × 1020Pcond (MW), where Pcond is the conducted power) is revisited both from the experimental and the modelling point of view. New developments with the EIRENE code, that allow relating measured CII emission intensities to the total amount of carbon sputtered from the Toroidal Pumped Limiter, are presented. Recent measurements carried out at high input power show a good agreement with the database used to establish the scaling law.

  20. Mineral Soil Carbon in Managed Hardwood Forests of the Northeastern US

    NASA Astrophysics Data System (ADS)

    Vario, C.; Friedland, A.; Hornig, C.

    2013-12-01

    New England is characterized by extensive forest cover and large reservoirs of soil carbon (C). In northern hardwood forests, mineral soil C can account for up to 50% of total ecosystem C. There has been an increasing demand for forests to serve both as a C sink and a renewable energy source, and effective management of the ecosystem C balance relies on accurate modeling of each compartment of the ecosystem. However, the dynamics of soil C storage with respect to forest use are variable and poorly understood, particularly in mineral soils. For example, current regional models assume C pools after forest harvesting do not change, while some studies suggest that belowground mineral soil C pools can be affected by disturbances at the soil surface. We quantified mineral soil C pools in previously clear-cut stands in seven research or protected forests across New York, New Hampshire, Massachusetts, and Vermont. The ages of the sites sampled ranged from recently cleared to those with no disturbance history, with 21 forest stands represented in the study. Within each research forest studied, physical parameters such as soil type, forest type, slope and land-use history (aside from forest harvest) did not vary between the stands of different ages. Soil samples were collected to a depth of 60 cm below the mineral-organic boundary using a gas-powered augur and 9.5-cm diameter drill bit. Samples were collected in 10-cm increments in shallow mineral soil and 15-cm increments from 30-60 cm depth. Carbon, nitrogen (N), pH, texture and soil mineralogy were measured across the regional sites. At Bartlett Experimental Forest (BEF) in New Hampshire, mineral soil biogeochemistry in cut and uncut sites was studied at a finer scale. Measurements included soil temperature to 55 cm depth, carbon compound analyses using Py-GCMS and soil microbial messenger RNA extractions from mineral soil. Finally, we simulated C dynamics after harvesting by building a model in Stella, with a particular

  1. CO2 Sequestraion by Mineral Carbonation of Cement Material

    NASA Astrophysics Data System (ADS)

    Jo, H.; Jang, Y.

    2010-12-01

    CO2 sequestration by mineral carbonation with cement materials was investigated in this study. Ca extraction and CO2 injection tests were conducted on three different materials (lime, Portland cement, waste concrete) using different extract reagents (NH4Cl, CH3COOH, HCl, and Deionized water) under ambient temperature and pressure conditions. CO2 gas (99.9%) was injected to either supernatant without solids or suspension with solids obtained from extraction tests at 4 ml/min of flow rate. Ca concentrations were measured from filtered solutions before and after CO2 injection. The chemical and mineralogical composition of raw materials and precipitates were determined using X-ray fluorescence and X-ray diffraction, respectively. The morphology and chemical composition of precipitates were analyzed with Field Emission Scanning Electron Microscopy equipped with the Energy Dispersive X-ray analysis. For the extraction tests, Ca concentrations of the extracts were related with the CaO content and type of CaO bearing minerals of the materials, regardless of the extraction solutions. Lime had a higher Ca concentration ranging between 942.7 and 39945.0 mg/L in the extracts than waste concrete (188.4 ~ 2978.1 mg/L) in the extracts due to its higher content of CaO (CaO : 24.5% and waste concrete : 20.3%). In contrast, the Portland cement (6346.0 and 28903.5 mg/L) had lower Ca concentrations than lime (94.27 ~ 39945.0 mg/L), even though the Portland cement (56.3%) had a higher CaO content than lime (24.5%). For a given extraction solution, lime had the highest CO2 carbonation efficiency. In addition, for a given material, the CO2 carbonation efficiency was the highest when NH4Cl solution was used as an extraction solution. Results of material analyses indicate that precipitates from the CO2 injection tests consisted of mostly CaCO3, regardless of types of materials and extraction solutions.

  2. Preparation of pure calcium carbonate by mineral carbonation using industrial byproduct FGD gypsum

    NASA Astrophysics Data System (ADS)

    Song, K.; Kim, W.; Bang, J. H.; Park, S.; Jeon, C. W.

    2015-12-01

    Mineral carbonation is one of the geological approaches for the sequestration of anthropogenic CO2 gas. Its concept is based on the natural weathering processes in which silicate minerals containing divalent cations such as Ca or Mg are carbonated to CaCO3 or MgCO3 in the reaction with CO2gas. Raw materials for the mineral carbonation have been extended to various industrial solid wastes such as steel slag, ashes, or FGD (flue gas desulfurization) gypsum which are rich in divalent cations. These materials have economic advantages when they are produced in CO2 emission sites. Flue gas desulfurization (FGD) gypsum is such a byproduct obtained in at coal-fired power plants. Recently, we carried out a research on the direct mineral carbonation of FGD gypsum for CO2sequestration. It showed high carbonation reactivity under ambient conditions and the process can be described as follows: CaSO4·2H2O + CO2(g) + 2NH4OH(aq) → CaCO3(s) + (NH4)2SO4(aq) (1) At the early stage of the process, calcium carbonate (CaCO3) exists as a dissolved ion pair during the induction period. High-purity CaCO3 could be precipitated from dissolved calcium carbonate solution extracted during the induction period. The effect of experimental parameters on pure CaCO3 was evaluated: CO2 flow rate (1-3 L/min), ammonia content (4-12%), and solid-to-liquid (S/L) ratio (5-300 g/L). FE-SEM (field-emission scanning electron microscopy) and XRD (X-ray diffraction) study revealed that the precipitated CaCO3 was round-shaped vaterite crystals. The induction time was inversely proportional to the CO2 flow rate and the yield for pure CaCO3 increased with the ammonia content. The formation efficiency for pure CaCO3 decreased with S/L (solid/liquid) ratio. It was 90% (mol/mol) when the S/L ratio was 5 g/L. However, S/L ratio didn't affect the maximum solubility limit of dissolved CaCO3.

  3. Mineral dissolution and precipitation in carbonate dominated terranes assessed using Mg isotopes

    NASA Astrophysics Data System (ADS)

    Tipper, E.; Calmels, D.; Gaillardet, J.; Galy, A.

    2013-12-01

    Carbonate weathering by carbonic acid consumes atmospheric CO2 during mineral dissolution, fixing it as aqueous bicarbonate over millennial time-scales. Ocean acidification has increased the solubility of CO2 in seawater by changing the balance of pH to alkalinity (the oceanic reservoir of carbon). This has lengthened the time-scale for CO2 sequestration by carbonate weathering to tens of thousands of years. At a global scale, the net consumption of CO2 is at least equal to that from silicate weathering, but there is far less work on carbonate weathering compared to silicate weathering because it has generally been assumed to be CO2 neutral on geological time-scales. Carbonate rocks are more readily dissolved than silicate rocks, meaning that their dissolution will likely respond much more rapidly to global environmental change when compared with the dissolution of silicate minerals. Although far less concentrated than Ca in many carbonates, Mg substitutes for Ca and is more concentrated than any other metal ion. Tracing the behavior of Mg in river waters, using Mg stable isotopes (26Mg/24Mg ratio expressed as delta26Mg in per mil units) is therefore a novel way to understand the complex series of dissolution/precipitation reactions that govern solute concentrations of Ca and Mg, and hence CO2 transfer by carbonate weathering. We present new Mg isotope data on a series of river and spring waters from the Jura mountains in North-East France. The stratigraphic column is relatively uniform throughout the Jura mountains and is dominated by limestones. As the limestone of the Jura Mountains were deposited in high-energy shallow water environments (shore line, lagoon and coral reefs), they are usually clay and organic poor. The delta26Mg of the local rocks is very constant at circa -4permil. The delta26Mg of the river waters is also fairly constant, but offset from the rock at -2.5permil. This is an intriguing observation because the dissolution of limestones is expected

  4. Long-Term Mineral Soil Carbon Response to Forest Harvesting in New England

    NASA Astrophysics Data System (ADS)

    Neurath, R. A.; Zummo, L. M.; Friedland, A. J.

    2010-12-01

    Soils are the largest global terrestrial carbon reservoir. In temperate systems, mineral soil horizons contain the largest fraction of the soil carbon pool. Disturbance of mineral soil due to land-use change results in the mineralization and release of carbon as carbon dioxide to the atmosphere. The dynamics of this response are poorly understood. We examined a chronosequence of forested plots harvested 5, 25, 55, 75, and 120 years ago, as well as an old growth plot, from the Bartlett Experimental Forest in New Hampshire to determine the magnitude and timing of carbon loss following forest biomass harvest. Our results show a significant, long-term depletion in mineral soil carbon following harvest. Total carbon concentrations declined 29% from the 5-year (79.8 Mg C ha-1) to the 55-year (56.4 Mg C ha-1) plots, and had still not reached full recovery in the 120-year (85.2 Mg C ha-1) plot, which contained 5.4 Mg C ha-1 less than at the 5-year plot. Carbon isotope (δ13C) results suggest microbial processes, stimulated by the physical disturbance of the soil, are responsible for the significant depletion of mineral soil carbon following harvest. Our study reveals the need to consider mineral soil carbon in forest management practices.

  5. Improving predictions of large scale soil carbon dynamics: Integration of fine-scale hydrological and biogeochemical processes, scaling, and benchmarking

    NASA Astrophysics Data System (ADS)

    Riley, W. J.; Dwivedi, D.; Ghimire, B.; Hoffman, F. M.; Pau, G. S. H.; Randerson, J. T.; Shen, C.; Tang, J.; Zhu, Q.

    2015-12-01

    Numerical model representations of decadal- to centennial-scale soil-carbon dynamics are a dominant cause of uncertainty in climate change predictions. Recent attempts by some Earth System Model (ESM) teams to integrate previously unrepresented soil processes (e.g., explicit microbial processes, abiotic interactions with mineral surfaces, vertical transport), poor performance of many ESM land models against large-scale and experimental manipulation observations, and complexities associated with spatial heterogeneity highlight the nascent nature of our community's ability to accurately predict future soil carbon dynamics. I will present recent work from our group to develop a modeling framework to integrate pore-, column-, watershed-, and global-scale soil process representations into an ESM (ACME), and apply the International Land Model Benchmarking (ILAMB) package for evaluation. At the column scale and across a wide range of sites, observed depth-resolved carbon stocks and their 14C derived turnover times can be explained by a model with explicit representation of two microbial populations, a simple representation of mineralogy, and vertical transport. Integrating soil and plant dynamics requires a 'process-scaling' approach, since all aspects of the multi-nutrient system cannot be explicitly resolved at ESM scales. I will show that one approach, the Equilibrium Chemistry Approximation, improves predictions of forest nitrogen and phosphorus experimental manipulations and leads to very different global soil carbon predictions. Translating model representations from the site- to ESM-scale requires a spatial scaling approach that either explicitly resolves the relevant processes, or more practically, accounts for fine-resolution dynamics at coarser scales. To that end, I will present recent watershed-scale modeling work that applies reduced order model methods to accurately scale fine-resolution soil carbon dynamics to coarse-resolution simulations. Finally, we

  6. A disconnect between O horizon and mineral soil carbon - Implications for soil C sequestration

    SciTech Connect

    Garten Jr, Charles T

    2009-01-01

    Changing inputs of carbon to soil is one means of potentially increasing carbon sequestration in soils for the purpose of mitigating projected increases in atmospheric CO{sub 2} concentrations. The effect of manipulations of aboveground carbon input on soil carbon storage was tested in a temperate, deciduous forest in east Tennessee, USA. A 4.5-year experiment included exclusion of aboveground litterfall and supplemental litter additions (three times ambient) in an upland and a valley that differed in soil nitrogen availability. The estimated decomposition rate of the carbon stock in the O horizon was greater in the valley than in the upland due to higher litter quality (i.e., lower C/N ratios). Short-term litter exclusion or addition had no effect on carbon stock in the mineral soil, measured to a depth of 30 cm, or the partitioning of carbon in the mineral soil between particulate- and mineral-associated organic matter. A two-compartment model was used to interpret results from the field experiments. Field data and a sensitivity analysis of the model were consistent with little carbon transfer between the O horizon and the mineral soil. Increasing aboveground carbon input does not appear to be an effective means of promoting carbon sequestration in forest soil at the location of the present study because a disconnect exists in carbon dynamics between O horizon and mineral soil. Factors that directly increase inputs to belowground soil carbon, via roots, or reduce decomposition rates of organic matter are more likely to benefit efforts to increase carbon sequestration in forests where carbon dynamics in the O horizon are uncoupled from the mineral soil.

  7. Carbon- and Sulfur-bearing Minerals in the Martian Meteorite ALH 84001

    NASA Astrophysics Data System (ADS)

    Romanek, C. S.; Thomas, K. L.; Gibson, E. K., Jr.; McKay, D. S.; Socki, R. A.

    1995-09-01

    Unusual carbonate minerals in ALH 84001 [1] provide insights into surficial processes that may have occurred on Mars, but despite detailed geochemical studies [2-4] carbonate petrogenesis has yet to be fully-characterized. High-resolution TEM and SEM analyses were performed on C- and S-bearing mineral grains to better constrain the nature and timing of carbonate mineralization events. Morphological elements: C- and S-bearing minerals in ALH 84001 commonly occur as spheroidal aggregates or fine-grained vug-filling structures. Spheroids are either orange or black, ~150 micrometers (+/- 50 micrometers) in diameter and highly-flattened (10-30 micrometers thick). Orange spheroids have limpid amber-colored cores and white to translucent mantles which are sometimes bound by thin black rims (< 10 micrometers). When viewed under cathodoluminescence, cores are non-luminescent while mantles luminesce a uniform bright-orange color. Black spheroids are less frequently observed; while they are similar in dimension to the orange spheroids they are chemically more heterogeneous. Black irregular aggregates fill residual pore-space between mineral grains. These structures are comprised of extremely fine-grained (< 2 micrometers) material that occasionally forms lenticular stringers up to 50 micrometers in length. Chemistry and Mineralogy: Small grains (30 micrometers dia.) were removed from C- and S-bearing aggregates, microtomed (~100 nm thick) and examined by TEM for imaging, electron diffraction, and elemental analysis. The orange spheroids have cores composed of Fe-Mg-Ca carbonate, with the centers having the highest concentration of Fe (45 mol%) and Ca (15 mol%). The concentration of Mg increases outward to almost pure MgCO3. TEM results support previous analyses of carbonate chemistry [1-4] and clearly indicate that a wide range of Mg-Fe-Ca solid solution exists in carbonate at a scale of ~10 nm. White mantles of the orange spheroids are composed of nearly pure MgCO3 (<5 mol

  8. ATOMIC-LEVEL IMAGING OF CO2 DISPOSAL AS A CARBONATE MINERAL: OPTIMIZING REACTION PROCESS DESIGN

    SciTech Connect

    M.J. McKelvy; R. Sharma; A.V.G. Chizmeshya; H. Bearat; R.W. Carpenter

    2002-11-01

    Fossil fuels, especially coal, can support the energy demands of the world for centuries to come, if the environmental problems associated with CO{sub 2} emissions can be overcome. Permanent and safe methods for CO{sub 2} capture and disposal/storage need to be developed. Mineralization of stationary-source CO{sub 2} emissions as carbonates can provide such safe capture and long-term sequestration. Mg-rich lamellar-hydroxide based minerals (e.g., brucite and serpentine) offer a class of widely available, low-cost materials, with intriguing mineral carbonation potential. Carbonation of such materials inherently involves dehydroxylation, which can disrupt the material down to the atomic level. As such, controlled dehydroxylation, before and/or during carbonation, may provide an important parameter for enhancing carbonation reaction processes. Mg(OH){sub 2} was chosen as the model material for investigating lamellar hydroxide mineral dehydroxylation/carbonation mechanisms due to (1) its structural and chemical simplicity, (2) interest in Mg(OH){sub 2} gas-solid carbonation as a potentially cost-effective CO{sub 2} mineral sequestration process component, and (3) its structural and chemical similarity to other lamellar-hydroxide-based minerals (e.g., serpentine-based minerals) whose carbonation reaction processes are being explored due to their low-cost CO{sub 2} sequestration potential. Fundamental understanding of the mechanisms that govern dehydroxylation/carbonation processes is essential for minimizing the cost of any lamellar-hydroxide-based mineral carbonation sequestration process. This final report covers the overall progress of this grant.

  9. ATOMIC-LEVEL IMAGING OF CO2 DISPOSAL AS A CARBONATE MINERAL: OPTIMIZING REACTION PROCESS DESIGN

    SciTech Connect

    M.J. McKelvy; R. Sharma; A.V.G. Chizmeshya; H. Bearat; R.W. Carpenter

    2001-10-01

    Fossil fuels, especially coal, can support the energy demands of the world for centuries to come, if the environmental problems associated with CO{sub 2} emissions can be overcome. Permanent and safe methods for CO{sub 2} capture and disposal/storage need to be developed. Mineralization of stationary-source CO{sub 2} emissions as carbonates can provide such safe capture and long-term sequestration. Mg-rich lamellar-hydroxide based minerals (e.g., brucite and serpentine) offer a class of widely available, low-cost materials, with intriguing mineral carbonation potential. Carbonation of such materials inherently involves dehydroxylation, which can disrupt the material down to the atomic level. As such, controlled dehydroxylation, before and/or during carbonation, may provide an important parameter for enhancing carbonation reaction processes. Mg(OH){sub 2} was chosen as the model material for investigating lamellar hydroxide mineral dehydroxylation/carbonation mechanisms due to (i) its structural and chemical simplicity, (ii) interest in Mg(OH){sub 2} gas-solid carbonation as a potentially cost-effective CO{sub 2} mineral sequestration process component, and (iii) its structural and chemical similarity to other lamellar-hydroxide-based minerals (e.g., serpentine-based minerals) whose carbonation reaction processes are being explored due to their low-cost CO{sub 2} sequestration potential. Fundamental understanding of the mechanisms that govern dehydroxylation/carbonation processes is essential for minimizing the cost of any lamellar-hydroxide-based mineral carbonation sequestration process. This report covers the third year progress of this grant, as well as providing an integrated overview of the progress in years 1-3, as we have been granted a one-year no-cost extension to wrap up a few studies and publications to optimize project impact.

  10. Large-scale carbon fiber tests

    NASA Technical Reports Server (NTRS)

    Pride, R. A.

    1980-01-01

    A realistic release of carbon fibers was established by burning a minimum of 45 kg of carbon fiber composite aircraft structural components in each of five large scale, outdoor aviation jet fuel fire tests. This release was quantified by several independent assessments with various instruments developed specifically for these tests. The most likely values for the mass of single carbon fibers released ranged from 0.2 percent of the initial mass of carbon fiber for the source tests (zero wind velocity) to a maximum of 0.6 percent of the initial carbon fiber mass for dissemination tests (5 to 6 m/s wind velocity). Mean fiber lengths for fibers greater than 1 mm in length ranged from 2.5 to 3.5 mm. Mean diameters ranged from 3.6 to 5.3 micrometers which was indicative of significant oxidation. Footprints of downwind dissemination of the fire released fibers were measured to 19.1 km from the fire.

  11. The Impact of Mineral Dissolution on Multiphase Flow in Permeable Carbonates

    NASA Astrophysics Data System (ADS)

    Krevor, S. C.; Niu, B.

    2015-12-01

    Carbon dioxide injection into deep saline aquifers is governed by a number of physicochemical processes at a broad range of spatial scales including mineral dissolution and precipitation, fluid flow, and capillary trapping. Past efforts have mostly focused on measuring the multiphase flow properties, capillarity, relative permeability, and residual trapping. However, the impact of fluid-rock interaction on these properties is less well understood. In this work we have made a series of measurements characterizing the impact of rock mineral dissolution on multiphase flow in three carbonate rocks. We used core flooding techniques to mimic reactive conditions representative of the near the well bore and far field regions of a carbonate reservoir CO2 injection project. Tests sequentially induced mineral dissolution and characterized the impacts on multiphase flow properties. Temperature retarded acid was used to uniformly dissolve calcite in Ketton, Estaillades, and Edward Brown rock cores. A single dissolution stages removed approximately 0.5% of the mass of the rocks and measurements of relative permeability and residual trapping were made after each stage along with mercury injection capillary pressure (MICP) to quantify the variation of in the pore size distribution. Three Stages were performed on each of carbonates rocks. Imaging with x-ray micro-CT and medical CT were used to quantify the porosity variation and observe the changes in pore structure and multiphase flow properties at scales from the um to the cm. The pore size distribution of the rocks was observed to both increase and become less uniform with progressive dissolution, as shown in Figure 1. For Ketton, the micro-pores, with size range from 0.01 um to 0.1um, have less been involved in the reaction than the macro-pores (10 um to 100 um). A larger spread in capillary trapping was seen around a characteristic initial-residual curve. Relative permeability changes with progressive dissolution was not well

  12. Carbon Mineralization by Aqueous Precipitation for Beneficial Use of CO2 from Flue Gas

    SciTech Connect

    Devenney, Martin; Gilliam, Ryan; Seeker, Randy

    2013-08-01

    The objective of this project is to demonstrate an innovative process to mineralize CO2 from flue gas directly to reactive carbonates and maximize the value and versatility of its beneficial use products. The program scope includes the design, construction, and testing of a CO2 Conversion to Material Products (CCMP) Pilot Demonstration Plant utilizing CO2 from the flue gas of a power production facility in Moss Landing, CA. This topical report covers Subphase 2a which is the design phase of pilot demonstration subsystems. Materials of construction have been selected and proven in both lab scale and prototype testing to be acceptable for the reagent conditions of interest. The target application for the reactive carbonate material has been selected based upon small-scale feasibility studies and the design of a continuous fiber board production line has been completed. The electrochemical cell architecture and components have been selected based upon both lab scale and prototype testing. The appropriate quality control and diagnostic techniques have been developed and tested along with the required instrumentation and controls. Finally the demonstrate site infrastructure, NEPA categorical exclusion, and permitting is all ready for the construction and installation of the new units and upgrades.

  13. Mineral trapping of CO2 in operated geothermal reservoirs - Numerical simulations on various scales

    NASA Astrophysics Data System (ADS)

    Kühn, Michael; Stanjek, Helge; Peiffer, Stefan; Clauser, Christoph

    2013-04-01

    A novel approach to store CO2 not only by hydrodynamic trapping within a reservoir, but to convert dissolved CO2 into the geochemically more stable form of calcite in a reaction with calcium obtained from dissolution of sulphates and alkalinity from feldspars or fly ashes is described here. The presentation gives answers to the key questions: • Where are potential geothermal reservoirs with anhydrite abundant? • Does the transfer of anhydrite into calcite work at all and what are the reaction rates? • What are probable alkalinity sources and how fast are they available? Numerical simulation is a means to quantify the entire process of CO2 storage and to deepen the understanding of the detailed chemical processes. We performed numerical simulations on multiple scales. The relevant scales reach from the micro or thin section scale (ca. 1 cm) to the reservoir scale (ca. 10 km). The idea is to provide constraints for smaller scale models from the larger scale and derive functionality from smaller scale models of processes which cannot be resolved in larger scale models, due to restrictions of discretization of the applied numerical mesh. With regard to the 3 questions above we can conclude that the combination of CO2 storage and geothermal energy production is generally feasible because candidate sites are available, anhydrite is transformable into calcite and alkalinity can be provided by fly ashes (Back et al. 2010) or even in-situ (Kühn and Clauser 2006). Based on our laboratory investigations and numerical studies we are able to estimate the storage potential for mineral trapping of CO2 in geothermal reservoirs (Kühn et al. 2009). On the one hand the maximum is unfortunately less than a million tons over the life time of a geothermal heating plant. On the other hand significant storage capacities are available in geological formations with regard to hydrodynamic trapping for millions of tonnes of carbon dioxide. This is why under the current circumstances

  14. DEVELOPMENT OF A CO2 SEQUESTRATION MODULE BY INTEGRATING MINERAL ACTIVATION AND AQUEOUS CARBONATION

    SciTech Connect

    George Alexander; M. Mercedes Maroto-Valer; Parvana Aksoy; Harold Schobert

    2006-03-25

    Mineral carbonation provides a potential option for the long-term storage of carbon dioxide. Serpentine has been chosen as the feedstock mineral, due to its abundance and availability. However, the relatively low reactivity of serpentine has warranted research into physical and chemical treatments that have been shown to greatly increase its reactivity. The use of sulfuric acid as an accelerating medium for the removal of magnesium from serpentine has recently been investigated. In addition to the challenges presented by the dissolution of serpentine, another challenge is the subsequent carbonation of the magnesium ions. A stable hydration sphere for the magnesium ion reduces the carbonation kinetics by obstructing the formation of the carbonation products. Accordingly, this research has evaluated the solubility of carbon dioxide in aqueous solution, the interaction between the dissociation products of carbon dioxide, and the carbonation potential of the magnesium ion.

  15. New strategies for submicron characterization the carbon binding of reactive minerals in long-term contrasting fertilized soils: implications for soil carbon storage

    NASA Astrophysics Data System (ADS)

    Xiao, Jian; He, Xinhua; Hao, Jialong; Zhou, Ying; Zheng, Lirong; Ran, Wei; Shen, Qirong; Yu, Guanghui

    2016-06-01

    Mineral binding is a major mechanism for soil carbon (C) stabilization. However, the submicron information about the in situ mechanisms of different fertilization practices affecting organo-mineral complexes and associated C preservation remains unclear. Here, we applied nano-scale secondary ion mass spectrometry (NanoSIMS), X-ray photoelectron spectroscopy (XPS), and X-ray absorption fine structure spectroscopy (XAFS) to examine differentiating effects of inorganic versus organic fertilization on interactions between highly reactive minerals and soil C preservation. To examine such interactions, soils and their extracted colloids were collected during a 24-year long-term fertilization period (1990-2014) (no fertilization, control; chemical nitrogen (N), phosphorus (P), and potassium (K) fertilization, NPK; and NPK plus swine manure fertilization, NPKM). The results for different fertilization conditions showed a ranked soil organic matter concentration with NPKM > NPK > control. Meanwhile, oxalate-extracted Al (Alo), Fe (Feo), short-range ordered Al (Alxps), Fe (Fexps), and dissolved organic carbon (DOC) ranked with NPKM > control > NPK, but the ratios of DOC / Alxps and DOC / Fexps ranked with NPKM > NPK > control. Compared with the NPK treatment, the NPKM treatment enhanced the C-binding loadings of Al and Fe minerals in soil colloids at the submicron scale. Furthermore, a greater concentration of highly reactive Al and Fe minerals was presented under NPKM than under NPK. Together, these submicron-scale findings suggest that both the reactive mineral species and their associations with C are differentially affected by 24-year long-term inorganic and organic fertilization.

  16. Diet influences rates of carbon and nitrogen mineralization from decomposing grasshopper frass and cadavers

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Insect herbivory can produce a pulse of mineral nitrogen (N) in soil from the decomposition of frass and cadavers. In this study we examined how diet quality affects rates of N and carbon (C) mineralization from grasshopper frass and cadavers. Frass was collected from grasshoppers fed natural or mer...

  17. Dissolution of CO2 in Brines and Mineral Reactions during Geological Carbon Storage: AN Eor Experiment

    NASA Astrophysics Data System (ADS)

    Bickle, M. J.; Chapman, H.; Galy, A.; Kampman, N.; Dubacq, B.; Ballentine, C. J.; Zhou, Z.

    2015-12-01

    Dissolution of CO2 in formation brines is likely to be a major process which stabilises stored CO2 on longer time scales and mitigates CO2 migrating through storage complexes. However very little is known about the likely rates of CO2 dissolution as CO2 flows through natural heterogeneous brine filled reservoirs. Here we report the results of sampling fluids over 6 months after a phase of CO2 injection commenced for enhanced oil recovery coupled with injection of isotopically enriched 3He and 129Xe. Modelling of the changes in fluid chemistry has previously been interpreted to indicate significant dissolution of silicate minerals where fluids remained close to saturation with calcite. These calculations, which are based on modal decomposition of changes in cation concentrations, are supported by changes in the isotopic compositions of Sr, Li and Mg. Analysis of Sr-isotopic compositions of samples from outcrops of the Frontier Formation, which forms the reservoir sampled by the EOR experiment, reveals substantial heterogeneity. Silicate mineral compositions have 87Sr/86Sr ratios between 0.709 and 0.719 whereas carbonate cements have values around 0.7076. Calculation of CO2 dissolution based on simplified 2-D flow models shows that fluids likely sample reservoir heterogeneities present on a finer scale with CO2 fingers occupying the most permeable horizons and most water flow in the adjacent slightly less permeable zones. Smaller time scale variations in 87Sr/86Sr ratios are interpreted to reflect variations in flow paths on small length scales driven by invading CO2.

  18. Pore-Scale Heterogeneity in the Mineral Distribution and Reactive Surface Area of Porous Rocks

    NASA Astrophysics Data System (ADS)

    Lai, P. E. P.; Krevor, S. C.

    2015-12-01

    The reactive surface area is an important control on interfacial processes between minerals and aqueous fluids in porous rocks. Spatial heterogeneity in the surface area can lead to complications in modelling reactive transport processes, but quantitative characterisation of this property has been limited. In this paper 3D images obtained using x-ray micro-tomography were used to characterise heterogeneity in surface area in one sandstone and five carbonate rocks. Measurements of average surface area from x-ray imagery were 1-2 orders of magnitude lower than measurements from nitrogen BET. A roughness factor, defined as the ratio of BET surface area to x-ray based surface area, was correlated to the presence of clay or microporosity. Coregistered images of Berea sandstone from x-ray and energy dispersive spectroscopy imagery were used to guide the identification of quartz, K-feldspar, dolomite, calcite and clays in x-ray images. In Berea sandstone, clay and K-feldspar had higher average surface area fractions than their volumetric fractions in the rock. In the Edwards carbonate, however, modal mineral composition correlated with surface area. By sub-sampling digital images, statistical distributions of the surface area were generated at various length scales of subsampling. Comparing these to distributions used in published modelling studies showed that the common practice of leaving surface area and pore volume uncorrelated in a pore leads to unrealistic combinations of surface area and pore volume in the models. We suggest these models adopt a moderate correlation based on observations. In Berea sandstone, constraining ratios of surface area to pore volume to a range of values between that of quartz-lined and five times that of clay-lined spheres appeared sufficient.

  19. Carbon Mineralization by Aqueous Precipitation for Beneficial Use of CO2 from Flue Gas

    SciTech Connect

    Brent Constantz; Randy Seeker; Martin Devenney

    2010-06-30

    Calera's innovative Mineralization via Aqueous Precipitation (MAP) technology for the capture and conversion of CO{sub 2} to useful materials for use in the built environment was further developed and proven in the Phase 1 Department of Energy Grant. The process was scaled to 300 gallon batch reactors and subsequently to Pilot Plant scale for the continuous production of product with the production of reactive calcium carbonate material that was evaluated as a supplementary cementitious material (SCM). The Calera SCM{trademark} was evaluated as a 20% replacement for ordinary portland cement and demonstrated to meet the industry specification ASTM 1157 which is a standard performance specification for hydraulic cement. The performance of the 20% replacement material was comparable to the 100% ordinary portland cement control in terms of compressive strength and workability as measured by a variety of ASTM standard tests. In addition to the performance metrics, detailed characterization of the Calera SCM was performed using advanced analytical techniques to better understand the material interaction with the phases of ordinary portland cement. X-ray synchrotron diffraction studies at the Advanced Photon Source in Argonne National Lab confirmed the presence of an amorphous phase(s) in addition to the crystalline calcium carbonate phases in the reactive carbonate material. The presence of carboaluminate phases as a result of the interaction of the reactive carbonate materials with ordinary portland cement was also confirmed. A Life Cycle Assessment was completed for several cases based on different Calera process configurations and compared against the life cycle of ordinary portland cement. In addition to the materials development efforts, the Calera technology for the production of product using an innovative building materials demonstration plant was developed beyond conceptual engineering to a detailed design with a construction schedule and cost estimate.

  20. A New Route for Unburned Carbon Concentration Measurements Eliminating Mineral Content and Coal Rank Effects

    PubMed Central

    Liu, Dong; Duan, Yuan-Yuan; Yang, Zhen; Yu, Hai-Tong

    2014-01-01

    500 million tons of coal fly ash are produced worldwide every year with only 16% of the total amount utilized. Therefore, potential applications using fly ash have both environmental and industrial interests. Unburned carbon concentration measurements are fundamental to effective fly ash applications. Current on-line measurement accuracies are strongly affected by the mineral content and coal rank. This paper describes a char/ash particle cluster spectral emittance method for unburned carbon concentration measurements. The char/ash particle cluster spectral emittance is predicted theoretically here for various unburned carbon concentrations to show that the measurements are sensitive to unburned carbon concentration but insensitive to the mineral content and coal rank at short wavelengths. The results show that the char/ash particle cluster spectral emittance method is a novel and promising route for unburned carbon concentration on-line measurements without being influenced by mineral content or coal rank effects. PMID:24691496

  1. Negative CO2 emissions via subsurface mineral carbonation in fractured peridotite

    NASA Astrophysics Data System (ADS)

    Kelemen, P. B.; Matter, J.

    2014-12-01

    Uptake of CO2 from surface water via mineral carbonation in peridotite can be engineered to achieve negative CO2 emissions. Reaction with peridotite, e.g., CO2 + olivine (A), serpentine (B) and brucite (C), forms inert, non-toxic, solid carbonates such as magnesite. Experimental studies show that A can be 80% complete in a few hours with 30 micron powders and elevated P(CO2) [1,2,3]. B is slower, but in natural systems the rate of B+C is significant [4]. Methods for capture of dilute CO2 via mineral carbonation [4,5,6,7] are not well known, though CO2 storage via mineral carbonation has been discussed for decades [8,9]. Where crushed peridotite is available, as in mine tailings, increased air or water flow could enhance CO2 uptake at a reasonable cost [4,5]. Here we focus on enhancing subsurface CO2 uptake from surface water flowing in fractured peridotite, in systems driven by thermal convection such as geothermal power plants. Return of depleted water to the surface would draw down CO2 from the air [6,7]. CO2 uptake from water, rate limited by flow in input and output wells, could exceed 1000 tons CO2/yr [7]. If well costs minus power sales were 0.1M to 1M and each system lasts 10 years this costs < 10 to 100 per ton CO2. As for other CCS methods, upscaling requires infrastructure resembling the oil industry. Uptake of 1 Gt CO2/yr at 1000 t/well/yr requires 1M wells, comparable to the number of producing oil and gas wells in the USA. Subsurface CO2 uptake could first be applied in coastal, sub-seafloor peridotite with onshore drilling. Sub-seafloor peridotite is extensive off Oman, New Caledonia and Papua New Guinea, with smaller amounts off Spain, Morocco, USA, etc. This would be a regional contribution, used in parallel with other methods elsewhere. To achieve larger scale is conceivable. There is a giant mass of seafloor peridotite along slow-spreading mid-ocean ridges. Could robotic drills enhance CO2 uptake at a reasonable cost, while fabric chimneys

  2. Carbon mineralization in surface and subsurface soils in a subtropical mixed forest in central China

    NASA Astrophysics Data System (ADS)

    Liu, F.; Tian, Q.

    2014-12-01

    About a half of soil carbon is stored in subsurface soil horizons, their dynamics have the potential to significantly affect carbon balancing in terrestrial ecosystems. However, the main factors regulating subsurface soil carbon mineralization are poorly understood. As affected by mountain humid monsoon, the subtropical mountains in central China has an annual precipitation of about 2000 mm, which causes strong leaching of ions and nutrition. The objectives of this study were to monitor subsurface soil carbon mineralization and to determine if it is affected by nutrient limitation. We collected soil samples (up to 1 m deep) at three locations in a small watershed with three soil layers (0-10 cm, 10-30 cm, below 30 cm). For the three layers, soil organic carbon (SOC) ranged from 35.8 to 94.4 mg g-1, total nitrogen ranged from 3.51 to 8.03 mg g-1, microbial biomass carbon (MBC) ranged from 170.6 to 718.4 μg g-1 soil. We measured carbon mineralization with the addition of N (100 μg N/g soil), P (50 μg P/g soil), and liable carbon (glucose labeled by 5 atom% 13C, at five levels: control, 10% MBC, 50% MBC, 100% MBC, 200% MBC). The addition of N and P had negligible effects on CO2 production in surface soil layers; in the deepest soil layer, the addition of N and P decreased CO2 production from 4.32 to 3.20 μg C g-1 soil carbon h-1. Glucose addition stimulated both surface and subsurface microbial mineralization of SOC, causing priming effects. With the increase of glucose addition rate from 10% to 200% MBC, the primed mineralization rate increased from 0.19 to 3.20 μg C g-1 soil carbon h-1 (fifth day of glucose addition). The magnitude of priming effect increased from 28% to 120% as soil layers go deep compare to the basal CO2 production (fifth day of 200% MBC glucose addition, basal CO2 production rate for the surface and the deepest soil was 11.17 and 2.88 μg C g-1 soil carbon h-1). These results suggested that the mineralization of subsurface carbon is more

  3. Carbon, nitrogen, and phosphorus mineralization in northern wetlands

    SciTech Connect

    Bridgham, S.D.; Updegraff, K.; Pastor, J.

    1998-07-01

    The authors examined rates of C, N, and P mineralization in soils from 16 northern Minnesota wetlands that occur across an ombrotrophic-minerotrophic gradient. Soils were incubated at 30 C under aerobic and anaerobic conditions for 59 wk, and the results were fit with a two-pool kinetic model. Additionally, 39 different soil quality variables were used in a principal components analysis (PCA) to predict mineralization rates. Mineralization of C, N, and P differed significantly among wetland types, aeration status (aerobic vs. anaerobic), and their interaction term. Despite low total soil N and P, there was a rapid turnover of the nutrient pools in ombrotrophic sites, particularly under aerobic conditions. On a volumetric basis, C and N mineralization increased in a predictable manner across the ombrotrophic-minerotrophic gradient, largely due to increasing soil bulk density. However, P mineralization per cubic centimeter remained relatively high in the bogs. The higher total P content of more minerotrophic soils appears to be offset by greater P immobilization due to geochemical sorption, yielding overall lower availability. Large differences in mineralization rates in northern wetland communities demonstrate that climate change models should not consider these areas as homogeneous entities.

  4. An Atomic Scale Look at the Thermodynamics and Kinetics of Mineralization

    NASA Astrophysics Data System (ADS)

    Villacampa, A.; Bartelt, M.; Orme, C.; Teng, H.; Dove, P.; De Yoreo, J.

    2001-12-01

    A common theme in biomineral growth is that biological systems use peptides and proteins to modify nucleation and growth of the inorganic phase. Developing a detailed physical picture of this process at the atomic-scale mechanisms naturally begins with an understanding of crystallization in the organic-free systems. Over the past eight years, atomic force microscopy has been used to investigate the growth of a wide variety of crystals from solution including many relevant to mineralization in biological systems such as calcium carbonate and calcium phosphate. The ability to observe growth in situ at molecular length scales using controlled solution compositions and conditions has led to significant advances in our understanding of crystal growth both in pure solutions and those containing organic additives that modify the growth morphology and kinetics. In many cases, the observed behavior has diverged significantly from that expected based on accepted atomistic models of growth. Here we use results of in situ AFM studies on calcite and brushite to illustrate aspects of our current understanding of mineralization that appear to be on a sound footing, and to highlight those areas where fundamental questions still remain unanswered. We examine three aspects of growth: step generation, step dynamics, and step kinetics. We find that analysis of the supersaturation dependence of step generation and kinetics call into question "rough step" models of growth that assume the applicability of the Gibbs-Thomson effect. We show that non-linear dependencies of step kinetics on supersturation are an immediate consequence of a "smooth step" model of growth. We use measurements of step edge fluctuations and terrace width distributions to determine the extent of step-step interactions and the pathways of mass transport at step edges. The significance of these results for understanding the role of organic modifiers will be discussed.

  5. Fine Milling and Mechanochemical Activation of Mine Wastes for Enhanced CO2 Mineral Carbonation

    NASA Astrophysics Data System (ADS)

    Hitch, M.; Li, J.; Dipple, G. M.

    2013-12-01

    Mechanical activation is an effective method to enhancing the physical architecture of mineral grains for mineral carbonation and CO2 sequestration. The advantage of this level of comminution is the disruption of the mineral structure and increase its reactivity. This paper discusses mechanochemical activation of whole rock tailings and compares three grinding methods (stirred, planetary and vibratory mills). Physical characteristics influencing CO2 mineral carbonation were measured using gas adsorption, infrared spectroscopy (FTIR) scanning electron microscopy (SEM), X-ray diffraction (XRD), and thermal gravity analysis (TGA). Results to date have indicated that indeed the mechanochemical activation leads to microstructure, structural and chemical changes of mixtures during high-energy milling. Direct aqueous mineral carbonation helped guide the author to the most effective mineral preparation method. Finally, Reitvelt analysis was used for quantitative analysis of the carbonate product. It was found that the activation mode controls the physio-chemical efficacy of the mine waste particle and was responsible for the differences in carbonate conversion.

  6. Amorphous calcium carbonate controls avian eggshell mineralization: A new paradigm for understanding rapid eggshell calcification.

    PubMed

    Rodríguez-Navarro, Alejandro B; Marie, Pauline; Nys, Yves; Hincke, Maxwell T; Gautron, Joel

    2015-06-01

    Avian eggshell mineralization is the fastest biogenic calcification process known in nature. How this is achieved while producing a highly crystalline material composed of large calcite columnar single crystals remains largely unknown. Here we report that eggshell mineral originates from the accumulation of flat disk-shaped amorphous calcium carbonate (ACC) particles on specific organic sites on the eggshell membrane, which are rich in proteins and sulfated proteoglycans. These structures known as mammillary cores promote the nucleation and stabilization of a amorphous calcium carbonate with calcitic short range order which predetermine the calcite composition of the mature eggshell. The amorphous nature of the precursor phase was confirmed by the diffuse scattering of X-rays and electrons. The nascent calcitic short-range order of this transient mineral phase was revealed by infrared spectroscopy and HRTEM. The ACC mineral deposited around the mammillary core sites progressively transforms directly into calcite crystals without the occurrence of any intermediate phase. Ionic speciation data suggest that the uterine fluid is equilibrated with amorphous calcium carbonate, throughout the duration of eggshell mineralization process, supporting that this mineral phase is constantly forming at the shell mineralization front. On the other hand, the transient amorphous calcium carbonate mineral deposits, as well as the calcite crystals into which they are converted, form by the ordered aggregation of nanoparticles that support the rapid mineralization of the eggshell. The results of this study alter our current understanding of avian eggshell calcification and provide new insights into the genesis and formation of calcium carbonate biominerals in vertebrates.

  7. Mineral Carbonation Potential of CO2 from Natural and Industrial-based Alkalinity Sources

    NASA Astrophysics Data System (ADS)

    Wilcox, J.; Kirchofer, A.

    2014-12-01

    Mineral carbonation is a Carbon Capture and Storage (CSS) technology where gaseous CO2 is reacted with alkaline materials (such as silicate minerals and alkaline industrial wastes) and converted into stable and environmentally benign carbonate minerals (Metz et al., 2005). Here, we present a holistic, transparent life cycle assessment model of aqueous mineral carbonation built using a hybrid process model and economic input-output life cycle assessment approach. We compared the energy efficiency and the net CO2 storage potential of various mineral carbonation processes based on different feedstock material and process schemes on a consistent basis by determining the energy and material balance of each implementation (Kirchofer et al., 2011). In particular, we evaluated the net CO2 storage potential of aqueous mineral carbonation for serpentine, olivine, cement kiln dust, fly ash, and steel slag across a range of reaction conditions and process parameters. A preliminary systematic investigation of the tradeoffs inherent in mineral carbonation processes was conducted and guidelines for the optimization of the life-cycle energy efficiency are provided. The life-cycle assessment of aqueous mineral carbonation suggests that a variety of alkalinity sources and process configurations are capable of net CO2 reductions. The maximum carbonation efficiency, defined as mass percent of CO2 mitigated per CO2 input, was 83% for CKD at ambient temperature and pressure conditions. In order of decreasing efficiency, the maximum carbonation efficiencies for the other alkalinity sources investigated were: olivine, 66%; SS, 64%; FA, 36%; and serpentine, 13%. For natural alkalinity sources, availability is estimated based on U.S. production rates of a) lime (18 Mt/yr) or b) sand and gravel (760 Mt/yr) (USGS, 2011). The low estimate assumes the maximum sequestration efficiency of the alkalinity source obtained in the current work and the high estimate assumes a sequestration efficiency

  8. Ballast minerals and the sinking carbon flux in the ocean: carbon-specific respiration rates and sinking velocities of macroscopic organic aggregates (marine snow)

    NASA Astrophysics Data System (ADS)

    Iversen, M. H.; Ploug, H.

    2010-05-01

    Recent observations have shown that fluxes of ballast minerals (calcium carbonate, opal, and lithogenic material) and organic carbon fluxes are closely correlated in the bathypelagic zones of the ocean. Hence it has been hypothesized that incorporation of biogenic minerals within marine aggregates could either protect the organic matter from decomposition and/or increase the sinking velocity via ballasting of the aggregates. Here we present the first combined data on size, sinking velocity, carbon-specific respiration rate, and composition measured directly in three aggregate types; Emiliania huxleyi aggregates (carbonate ballasted), Skeletonema costatum aggregates (opal ballasted), and aggregates made from a mix of both E. huxleyi and S. costatum (carbonate and opal ballasted). Overall average carbon-specific respiration rate was ~0.13 d-1 and did not vary with aggregate type and size. Ballasting from carbonate resulted in 2- to 2.5-fold higher sinking velocities than aggregates ballasted by opal. We compiled literature data on carbon-specific respiration rate and sinking velocity measured in aggregate of different composition and sources. Compiled carbon-specific respiration rates (including this study) vary between 0.08 d-1 and 0.20 d-1. Sinking velocity increases with increasing aggregate size within homogeneous sources of aggregates. When compared across different particle and aggregate sources, however, sinking velocity appeared to be independent of particle or aggregate size. The calculated carbon remineralization length scale due to microbial respiration and sinking velocity of mm-large marine aggregates was higher for calcite ballasted aggregates as compared to opal-ballasted aggregates. It varied between 0.0002 m-1 and 0.0030 m-1, and decreased with increasing aggregate size.

  9. Synthesis of supported carbon nanotubes in mineralized silica-wood composites

    SciTech Connect

    Shin, Yongsoon; Wang, Chong M.; Li, Xiaohong S.; Exarhos, Gregory J.

    2005-03-01

    Multiwall carbon nanotubes (MWNTs) form spontaneously upon graphitization of organic precursors bound to the internal surfaces of a high porosity mineralized sample of natural wood. Following HF etching, both mesostructured carbon and randomly distributed and intertwined MWNTs were seen throughout the wood cellular structure.

  10. [A NIR qualitative and quantitative model of 8 kinds of carbonate-containing mineral Chinese medicines].

    PubMed

    Yuan, Ming-Yang; Huang, Bi-Sheng; Yu, Chi; Liu, Yi-Mei; Chen, Ke-Li

    2014-01-01

    The aim of this paper is to apply near infrared spectroscopy techniques to construct a rapid identification method for 8 kinds of mineral Chinese Medicines containing carbonates. The qualitative model using clustering analysis method in OPUS software can identify accurately 8 kinds of carbonate-containing mineral Chinese medicines. The near-infrared quantitative model was established by using partial least squares method (PLS) for 7 mineral Chinese Medicines in which main component is calcium carbonate. Compared with the results by EDTA titration, the established quantitative analysis model for calcium carbonate content showed a good prediction result that when the content is between 47.61% -99.17%, the average relative deviation of the prediction result is 0.24% and the average recovery rate was 100.3%. The results also showed that the model using near infrared spectroscopy can get not only a rapid identification of the 8 mineral Chinese medicines containing carbonates, but also an accurate and reliabe content determination of calcium carbonate for the 7 mineral Chinese medicines which contain the component.

  11. Development of models for predicting carbon mineralization and associated phytotoxicity in compost-amended soil.

    PubMed

    Aslam, Danielle N; Vandergheynst, Jean S; Rumsey, Thomas R

    2008-12-01

    Phytotoxicity of compost-amended soil is related to carbon mineralization associated with compost decomposition. The objective of this research was to determine if compost carbon mineralization potential, estimated using compost respiration rate measurements, could be combined with carbon mineralization kinetic models to predict phytotoxicity of compost-amended soil. First-order, second-order, and Monod kinetic models that include compost carbon mineralization potential, compost amendment rate, incubation time, and temperature were developed and compared for their ability to predict carbon mineralization kinetics. Experiments utilized two soil types amended with 0%, 5%, and 50% (v/v) food waste and green waste composts, incubated at 20 degrees C, 25 degrees C, 30 degrees C, 35 degrees C, and 45 degrees C for model development and under a diurnal temperature cycle from 20 degrees C to 30 degrees C for model validation. For most cases, a first-order model had an equivalent or better fit to the data than the other models. Mineralizable carbon estimated using the first-order model was significantly correlated to the probability of phytotoxicity in compost-amended soil.

  12. Recent developments and perspectives on the treatment of industrial wastes by mineral carbonation — a review

    NASA Astrophysics Data System (ADS)

    Bodor, Marius; Santos, Rafael M.; Van Gerven, Tom; Vlad, Maria

    2013-12-01

    Besides producing a substantial portion of anthropogenic CO2 emissions, the industrial sector also generates significant quantities of solid residues. Mineral carbonation of alkaline wastes enables the combination of these two by-products, increasing the sustainability of industrial activities. On top of sequestering CO2 in geochemically stable form, mineral carbonation of waste materials also brings benefits such as stabilization of leaching, basicity and structural integrity, enabling further valorization of the residues, either via reduced waste treatment or landfilling costs, or via the production of marketable products. This paper reviews the current state-of-the-art of this technology and the latest developments in this field. Focus is given to the beneficial effects of mineral carbonation when applied to metallurgical slags, incineration ashes, mining tailings, asbestos containing materials, red mud, and oil shale processing residues. Efforts to intensify the carbonation reaction rate and improve the mineral conversion via process intensification routes, such as the application of ultrasound, hot-stage processing and integrated reactor technologies, are described. Valorization opportunities closest to making the transition from laboratory research to commercial reality, particularly in the form of shaped construction materials and precipitated calcium carbonate, are highlighted. Lastly, the context of mineral carbonation among the range of CCS options is discussed.

  13. Interface Induced Carbonate Mineralization: A Fundamental Geochemical Process Relevant to Carbon Sequestration

    SciTech Connect

    Teng, H. Henry; Xu, Huifang

    2013-07-17

    We have approached the long-standing geochemical question why anhydrous high-Mg carbonate minerals (i.e., magnesite and dolomite) cannot be formed at ambient conditions from a new perspective by exploring the formation of MgCO{sub 3} and Mg{sub x}Ca{sub (1-x)}CO{sub 3} in non-aqueous solutions. Data collected from our experiments in this funding period suggest that a fundamental barrier, other than cation hydration, exists that prevents Mg{sup 2+} and CO{sub 3}{sup 2-} ions from forming long-range ordered structures. We propose that this barrier mainly stems from the lattice limitation on the spatial configuration of CO{sub 3} groups in magnesite crystals. On the other hand, the measured higher distribution coefficients of Mg between magnesian calcites formed in the absence and presence of water give us a first direct proof to support and quantify the cation hydration effect.

  14. Modulation of the early pre- and post-nucleation stages of scale forming minerals by a commercial copolymer

    NASA Astrophysics Data System (ADS)

    Ruiz-Agudo, Cristina; Putnis, Christine; Ibañez-Velasco, Aurelia; Ruiz-Agudo, Encarnación; Putnis, Andrew

    2016-04-01

    Mineral precipitation is a substantial hazard for multiple technological applications, leading frequently to the formation of thick scale deposits that can completely block fluid circulation in different industrial processes. Polymeric scale inhibitors are commonly used to mitigate or retard these unwanted mineral precipitation reactions. Here we study the mechanisms by which a commercial copolymer of maleic acid/allyl sulfonic acid with phosphonate groups (MASP), commonly used in the oil recovery industry, modulate the precipitation of two common scale forming minerals, calcite and barite. We found that MASP does not significantly affect the equilibrium of pre-nucleation aggregates in both systems, while it seems to prevent the aggregation of prenucleation associates by incomplete stabilization, thereby inhibiting (at least temporarily) the nucleation of a solid phase. Moreover, it influences polymorph selection in the CaCO3, as in the presence of this additive nucleation occurs at high supersaturation via amorphous calcium carbonate that later transform into calcite, while in control runs (i.e. no MASP present) the direct formation of vaterite is observed.

  15. How relevant is chemical recalcitrance for predicting climatic effects on mineral soil carbon stocks?

    NASA Astrophysics Data System (ADS)

    Hopkins, F. M.; Torn, M. S.; Trumbore, S.

    2011-12-01

    The role of chemical recalcitrance in mediating the effect of warming on soil carbon stocks has been a focus of research efforts aimed toward the larger goal of prediction of carbon loss from soils in the 21st century. Arrhenius kinetics provides a theoretical basis for the prediction that reaction of chemically recalcitrant carbon compounds (those with higher activation energy) should be more temperature sensitive than compounds with faster turnover rates (lower activation energy). This relationship has even been integrated into models of soil carbon dynamics. However, since chemically recalcitrant compounds have, by definition, slower turnover rates, their response to warming should ultimately be far smaller than those of faster turnover compounds in terms of overall respiratory loss (Sierra 2011). Regardless of the relative temperature sensitivity of recalcitrant soil carbon, it remains an open question how important enhanced decomposition of chemically recalcitrant carbon in mineral soils is for potential feedbacks between warming and soil carbon stocks. To lend insight to this question, we present a series of incubation warming experiments with soils from two forest Free Air CO2 Enrichment (FACE) sites. Because of the distinct carbon isotope (radiocarbon free) signature of the CO2 fumigation gas, soil carbon in elevated CO2 plots has incorporated a decade of labeled carbon. By measuring the radiocarbon signature of flux, which reflects FACE label carbon in CO2 elevated plots, and the atmospheric history of radiocarbon in CO2 control plots, we attributed warming-induced increases in flux rates to soil carbon pools of different ages. Much of our knowledge about decomposition of recalcitrant compounds comes from litter decomposition, where chemical recalcitrance is the presumed control on decomposition rates. By comparing the response of litter and mineral soils to warming, we infer the role of chemical recalcitrance in mineral soils. Flux rates from both organic

  16. The Black Lake (Quebec, Canada) mineral carbonation experimental station: CO2 capture in mine waste

    NASA Astrophysics Data System (ADS)

    Beaudoin, G.; Constantin, M.; Duchesne, J.; Dupuis, C.; Entrazi, A.; Gras, A.; Huot, F.; Fortier, R.; Hebert, R.; Larachi, F.; Lechat, K.; Lemieux, J. M.; Molson, J. W. H.; Maldague, X.; Therrien, R.; Assima, G. P.

    2014-12-01

    Passive mineral carbonation of chrysotile mining and milling waste was discovered at the Black Lake mine, southern Québec, 10 years ago. Indurated crusts were found at the surface and within waste piles where mineral and rock fragments are cemented by hydrated magnesium carbonates. A long-term research program has yielded significant insight into the process of CO2 capture from the atmosphere, and how it can be implemented during mining operations. Laboratory experiments show that the waste mineralogy is crucial, brucite being more reactive than serpentine. Partial water saturation, circa 40%, is also critical to dissolve magnesium from minerals, and transport aqueous CO2 to precipitation sites. Grain armoring by iron oxidation induced by dissolved oxygen prevents further reaction. Two experimental cells constructed with milling waste and fitted with various monitoring probes (T, H2O content, leachate) and gas sampling ports, have been monitored for more than 3 years, along with environmental conditions. The interstitial gas in the cells remains depleted in CO2 indicating continuous capture of ambient atmospheric CO2 at rates faster than advection to reaction sites. The energy released by the exothermic mineral carbonation reactions has been observed both in laboratory experiments (up to 4 °C) and in the field. Warm air, depleted to 10 ppmv CO2, vents at the surface of the waste piles, indicating reaction with atmospheric CO2 deep inside the piles. A thermal anomaly, detected by airborne infrared and coincident with a known venting area, was selected for locating a 100 m deep borehole fitted with sensor arrays to monitor active mineral carbonation within the pile. The borehole has intersected areas where mineral carbonation has indurated the milling waste. The borehole will be monitored for the next 3 years to better understand the mineral carbonation process, and its potential to yield recoverable geothermal energy in mining environments.

  17. Environmental and substrate controls over carbon and nitrogen mineralization in northern wetlands

    SciTech Connect

    Updegraff, K.; Pastor, J.; Bridgham, S.D.; Johnston, C.A.

    1995-02-01

    Northern wetlands may be a potential carbon source to the atmosphere upon global warming, particularly with regard to methane. Three wetland soils were incubated for 80 wk in the laboratory under both aerobic and anaerobic conditions at 15{degrees} and 30{degrees}C. The soils were obtained from a Scirpus-Carex-dominated meadow in an abandoned beaver pond and from the surface and at 1 m depth of a spruce (Picea)-Sphagnum bog in Voyageurs National Park, Minnesota. The responses of nitrogen mineralization, carbon mineralization, and trace gas partitioning to both temperature and aeration depended strongly on the substrate quality of the soils. Sedge meadow soil had the highest nitrogen and carbon mineralization rates and methane production under anaerobic conditions, and carbon mineralization under aerobic conditions, but the surface peats had the highest nitrogen mineralization rates under aerobic conditions. Methanogenesis was highest in sedge soil but less sensitive to temperature than the peats. Most of the variation in nitrogen and carbon mineralization among the soils and treatments was accounted for by differences in the size and kinetics of a relatively small labile pool. The kinetics of this pool were more sensitive to changes in temperature and aeration than that of the larger recalcitrant pool. Principal components analysis separated the soils on the basis of labile and recalcitrant carbon fractions. Total C and N mineralization correlated positively with the factor representing labile elements, while methanogenesis also showed a negative correlation with the factor representing recalcitrant elements. Estimates of atmospheric feedbacks from northern wetlands upon climatic change must account for extreme local variation in substrate quality and wetland type; global projections based on extrapolations from a few field measurements do not account for this local variation and may be in error. 52 refs., 4 figs., 6 tabs.

  18. Continuing Studies on Direct Aqueous Mineral Carbonation of CO{sub 2} Sequestration

    SciTech Connect

    O'Connor, W.K.; Dahlin, D.C.; Nilsen, D.N.; Gerdemann, S.J.; Rush, G.E.; Penner, L.R.; Walters, R.P.; Turner, P.C.

    2002-03-04

    Direct aqueous mineral carbonation has been investigated as a process to convert gaseous CO{sub 2} into a geologically stable, solid final form. The process utilizes a solution of sodium bicarbonate (NaHCO{sub 3}), sodium chloride (NaCl), and water, mixed with a mineral reactant, such as olivine (Mg{sub 2}SiO{sub 4}) or serpentine [Mg{sub 3}Si{sub 2}O{sub 5}(OH){sub 4}]. Carbon dioxide is dissolved into this slurry, by diffusion through the surface and gas dispersion within the aqueous phase. The process includes dissolution of the mineral and precipitation of the magnesium carbonate mineral magnesite (MgCO{sub 3}) in a single unit operation. Activation of the silicate minerals has been achieved by thermal and mechanical means, resulting in up to 80% stoichiometric conversion of the silicate to the carbonate within 30 minutes. Heat treatment of the serpentine, or attrition grinding of the olivine and/or serpentine, appear to activate the minerals by the generation of a non-crystalline phase. Successful conversion to the carbonate has been demonstrated at ambient temperature and relatively low (10 atm) partial pressure of CO{sub 2} (P{sub CO2}). However, optimum results have been achieved using the bicarbonate-bearing solution, and high P{sub CO2}. Specific conditions include: 185 C; P{sub CO2}=150 atm; 30% solids. Studies suggest that the mineral dissolution rate is not solely surface controlled, while the carbonate precipitation rate is primarily dependent on the bicarbonate concentration of the slurry. Current and future activities include further examination of the reaction pathways and pretreatment options, the development of a continuous flow reactor, and an evaluation of the economic feasibility of the process.

  19. Effect of sulfate and carbonate minerals on particle-size distributions in arid soils

    USGS Publications Warehouse

    Goossens, Dirk; Buck, Brenda J.; Teng, Yuazxin; Robins, Colin; Goldstein, Harland L.

    2014-01-01

    Arid soils pose unique problems during measurement and interpretation of particle-size distributions (PSDs) because they often contain high concentrations of water-soluble salts. This study investigates the effects of sulfate and carbonate minerals on grain-size analysis by comparing analyses in water, in which the minerals dissolve, and isopropanol (IPA), in which they do not. The presence of gypsum, in particular, substantially affects particle-size analysis once the concentration of gypsum in the sample exceeds the mineral’s solubility threshold. For smaller concentrations particle-size results are unaffected. This is because at concentrations above the solubility threshold fine particles cement together or bind to coarser particles or aggregates already present in the sample, or soluble mineral coatings enlarge grains. Formation of discrete crystallites exacerbates the problem. When soluble minerals are dissolved the original, insoluble grains will become partly or entirely liberated. Thus, removing soluble minerals will result in an increase in measured fine particles. Distortion of particle-size analysis is larger for sulfate minerals than for carbonate minerals because of the much higher solubility in water of the former. When possible, arid soils should be analyzed using a liquid in which the mineral grains do not dissolve, such as IPA, because the results will more accurately reflect the PSD under most arid soil field conditions. This is especially important when interpreting soil and environmental processes affected by particle size.

  20. Effects of switching from calcium carbonate to lanthanum carbonate on bone mineral metabolism in hemodialysis patients.

    PubMed

    Manabe, Rie; Fukami, Kei; Ando, Ryotaro; Sakai, Kazuko; Kusumoto, Takuo; Hazama, Takuma; Adachi, Takeki; Kaida, Yusuke; Nakayama, Yosuke; Ueda, Seiji; Kohno, Keisuke; Wada, Yoshifumi; Yamagishi, Sho-ichi; Okuda, Seiya

    2013-04-01

    Phosphate binders are useful for the treatment of hyperphosphatemia in hemodialysis (HD) patients. This study was performed to examine the effects of switching from calcium carbonate (CC) to lanthanum carbonate (LC) on bone mineral metabolism and inflammatory markers in HD patients. We conducted 29 stable HD patients receiving CC, which was replaced by LC and followed-up for 12 weeks. Patients underwent determinants of blood chemistries such as serum calcium (Ca), phosphorus, parathyroid hormone (PTH) and vitamin D status, and interleukin-6 (IL-6) mRNA levels in whole blood cells were evaluated by real-time PCR just before and after the treatment with LC. Corrected Ca [corrected] levels were significantly reduced, but serum phosphorus levels (P levels) were unchanged after LC treatment. Switching to LC increased whole-PTH, osteocalcin, 1,25(OH)(2) D(3) levels and 1,25(OH)(2) D(3)/25(OH)D(3) ratio. 1,25(OH)(2) D(3)/25(OH)D(3) ratio was negatively correlated with HD duration. Furthermore, whole blood cell IL-6 mRNA levels were significantly reduced by LC treatment. We provided that the switching from CC to LC improved Ca overload and ameliorated vitamin D and inflammatory status in HD patients. These observations suggest that LC may play a protective role for the progression of atherosclerosis and vascular calcification in these patients.

  1. Direct electrolytic dissolution of silicate minerals for air CO2 mitigation and carbon-negative H2 production.

    PubMed

    Rau, Greg H; Carroll, Susan A; Bourcier, William L; Singleton, Michael J; Smith, Megan M; Aines, Roger D

    2013-06-18

    We experimentally demonstrate the direct coupling of silicate mineral dissolution with saline water electrolysis and H2 production to effect significant air CO2 absorption, chemical conversion, and storage in solution. In particular, we observed as much as a 10(5)-fold increase in OH(-) concentration (pH increase of up to 5.3 units) relative to experimental controls following the electrolysis of 0.25 M Na2SO4 solutions when the anode was encased in powdered silicate mineral, either wollastonite or an ultramafic mineral. After electrolysis, full equilibration of the alkalized solution with air led to a significant pH reduction and as much as a 45-fold increase in dissolved inorganic carbon concentration. This demonstrated significant spontaneous air CO2 capture, chemical conversion, and storage as a bicarbonate, predominantly as NaHCO3. The excess OH(-) initially formed in these experiments apparently resulted via neutralization of the anolyte acid, H2SO4, by reaction with the base mineral silicate at the anode, producing mineral sulfate and silica. This allowed the NaOH, normally generated at the cathode, to go unneutralized and to accumulate in the bulk electrolyte, ultimately reacting with atmospheric CO2 to form dissolved bicarbonate. Using nongrid or nonpeak renewable electricity, optimized systems at large scale might allow relatively high-capacity, energy-efficient (<300 kJ/mol of CO2 captured), and inexpensive (<$100 per tonne of CO2 mitigated) removal of excess air CO2 with production of carbon-negative H2. Furthermore, when added to the ocean, the produced hydroxide and/or (bi)carbonate could be useful in reducing sea-to-air CO2 emissions and in neutralizing or offsetting the effects of ongoing ocean acidification. PMID:23729814

  2. Direct electrolytic dissolution of silicate minerals for air CO2 mitigation and carbon-negative H2 production

    PubMed Central

    Rau, Greg H.; Carroll, Susan A.; Bourcier, William L.; Singleton, Michael J.; Smith, Megan M.; Aines, Roger D.

    2013-01-01

    We experimentally demonstrate the direct coupling of silicate mineral dissolution with saline water electrolysis and H2 production to effect significant air CO2 absorption, chemical conversion, and storage in solution. In particular, we observed as much as a 105-fold increase in OH− concentration (pH increase of up to 5.3 units) relative to experimental controls following the electrolysis of 0.25 M Na2SO4 solutions when the anode was encased in powdered silicate mineral, either wollastonite or an ultramafic mineral. After electrolysis, full equilibration of the alkalized solution with air led to a significant pH reduction and as much as a 45-fold increase in dissolved inorganic carbon concentration. This demonstrated significant spontaneous air CO2 capture, chemical conversion, and storage as a bicarbonate, predominantly as NaHCO3. The excess OH− initially formed in these experiments apparently resulted via neutralization of the anolyte acid, H2SO4, by reaction with the base mineral silicate at the anode, producing mineral sulfate and silica. This allowed the NaOH, normally generated at the cathode, to go unneutralized and to accumulate in the bulk electrolyte, ultimately reacting with atmospheric CO2 to form dissolved bicarbonate. Using nongrid or nonpeak renewable electricity, optimized systems at large scale might allow relatively high-capacity, energy-efficient (<300 kJ/mol of CO2 captured), and inexpensive (<$100 per tonne of CO2 mitigated) removal of excess air CO2 with production of carbon-negative H2. Furthermore, when added to the ocean, the produced hydroxide and/or (bi)carbonate could be useful in reducing sea-to-air CO2 emissions and in neutralizing or offsetting the effects of ongoing ocean acidification. PMID:23729814

  3. Direct electrolytic dissolution of silicate minerals for air CO2 mitigation and carbon-negative H2 production.

    PubMed

    Rau, Greg H; Carroll, Susan A; Bourcier, William L; Singleton, Michael J; Smith, Megan M; Aines, Roger D

    2013-06-18

    We experimentally demonstrate the direct coupling of silicate mineral dissolution with saline water electrolysis and H2 production to effect significant air CO2 absorption, chemical conversion, and storage in solution. In particular, we observed as much as a 10(5)-fold increase in OH(-) concentration (pH increase of up to 5.3 units) relative to experimental controls following the electrolysis of 0.25 M Na2SO4 solutions when the anode was encased in powdered silicate mineral, either wollastonite or an ultramafic mineral. After electrolysis, full equilibration of the alkalized solution with air led to a significant pH reduction and as much as a 45-fold increase in dissolved inorganic carbon concentration. This demonstrated significant spontaneous air CO2 capture, chemical conversion, and storage as a bicarbonate, predominantly as NaHCO3. The excess OH(-) initially formed in these experiments apparently resulted via neutralization of the anolyte acid, H2SO4, by reaction with the base mineral silicate at the anode, producing mineral sulfate and silica. This allowed the NaOH, normally generated at the cathode, to go unneutralized and to accumulate in the bulk electrolyte, ultimately reacting with atmospheric CO2 to form dissolved bicarbonate. Using nongrid or nonpeak renewable electricity, optimized systems at large scale might allow relatively high-capacity, energy-efficient (<300 kJ/mol of CO2 captured), and inexpensive (<$100 per tonne of CO2 mitigated) removal of excess air CO2 with production of carbon-negative H2. Furthermore, when added to the ocean, the produced hydroxide and/or (bi)carbonate could be useful in reducing sea-to-air CO2 emissions and in neutralizing or offsetting the effects of ongoing ocean acidification.

  4. Carbon and nitrogen mineralization in vineyard acid soils amended with a bentonitic winery waste

    NASA Astrophysics Data System (ADS)

    Fernández-Calviño, David; Rodríguez-Salgado, Isabel; Pérez-Rodríguez, Paula; Díaz-Raviña, Montserrat; Nóvoa-Muñoz, Juan Carlos; Arias-Estévez, Manuel

    2015-04-01

    Carbon mineralization and nitrogen ammonification processes were determined in different vineyard soils. The measurements were performed in samples non-amended and amended with different bentonitic winery waste concentrations. Carbon mineralization was measured as CO2 released by the soil under laboratory conditions, whereas NH4+ was determined after its extraction with KCl 2M. The time evolution of both, carbon mineralization and nitrogen ammonification, was followed during 42 days. The released CO2 was low in the analyzed vineyard soils, and hence the metabolic activity in these soils was low. The addition of the bentonitic winery waste to the studied soils increased highly the carbon mineralization (2-5 fold), showing that the organic matter added together the bentonitic waste to the soil have low stability. In both cases, amended and non-amended samples, the maximum carbon mineralization was measured during the first days (2-4 days), decreasing as the incubation time increased. The NH4+ results showed an important effect of bentonitic winery waste on the ammonification behavior in the studied soils. In the non-amended samples the ammonification was no detected in none of the soils, whereas in the amended soils important NH4+ concentrations were detected. In these cases, the ammonification was fast, reaching the maximum values of NH4 between 7 and 14 days after the bentonitic waste additions. Also, the percentages of ammonification respect to the total nitrogen in the soil were high, showing that the nitrogen provided by the bentonitic waste to the soil is non-stable. The fast carbon mineralization found in the soils amended with bentonitic winery wastes shows low possibilities of the use of this waste for the increasing the organic carbon pools in the soil.On the other hand, the use of this waste as N-fertilizer can be possible. However, due its fast ammonification, the waste should be added to the soils during active plant growth periods.

  5. Carbonate-mineral/water interactions in sulfide-rich mine tailings

    NASA Astrophysics Data System (ADS)

    Al, Tom A.; Martin, Chris J.; Blowes, David W.

    2000-12-01

    The chemical composition and mineralogy of coatings on carbonate minerals from mine tailings have been studied using aqueous geochemical methods, Time-of-Flight Laser-Ionization Mass Spectrometry (TOF-LIMS) and Transmission Electron Microscopy (TEM). The goal is to study major and trace element partitioning between the aqueous and solid phase, and to infer mechanisms that control the concentrations of elements in the pore water of sulfide-rich mine tailings. Pore-water samples and carbonate-mineral grains were collected from four geochemically distinct zones within the tailings. Oxidation of sulfide minerals near the surface results in a large range in pore-water pH (3.85 to 6.98) and aqueous concentrations of metals and sulfate. With increasing depth in the tailings, mineral-water interactions lead to increasing pH, and decreasing concentrations of metals and sulfate. Calculated mineral saturation indices, trends in the abundance of Ca, Fe, Mg and Mn in TOF-LIMS profiles through the secondary coatings, and electron diffraction patterns obtained from the coatings, suggest that precipitation/dissolution of jarosite-group minerals, gypsum, goethite, akaganéite, amorphous Fe oxyhydroxides and siderite control the aqueous Ca, Fe, Na, K and SO 4 concentrations. The occurrence of secondary coatings on primary minerals is widespread, and reactions with the secondary minerals, rather than the primary mineral substrate, probably represent the principal controls on trace-element distributions in the pore water. The data indicate that adsorption, surface-complexation and co-precipitation reactions are important controls on the concentrations of trace elements in the pore water. The occurrence of siderite coatings on the surface of ankerite grains suggests that Fe-bearing dolomite-structure carbonate minerals dissolve incongruently. This corroborates inferences made by previous workers that solubility differences between calcite and siderite lead to calcite dissolution and

  6. FT-Raman spectroscopic study of calcium-rich and magnesium-rich carbonate minerals.

    PubMed

    Edwards, Howell G M; Villar, Susana E Jorge; Jehlicka, Jan; Munshi, Tasnim

    2005-08-01

    Calcium and magnesium carbonates are important minerals found in sedimentary environments. Although sandstones are the most common rock colonized by endolith organisms, the production of calcium and magnesium carbonates is important in survival strategies of organisms and as a source for the removal of oxalate ions. Extremophile organisms in some situations may convert or destroy carbonates of calcium and magnesium, which gives important information about the conditions under which these organisms can survive. The identification on the surface of Mars of 'White Rock' formations, in Juventae Chasma or Sabaea Terra, as possibly carbonate rocks makes the study of these minerals a prerequisite of remote Martian exploration. Here, we show the protocol for the identification by Raman spectroscopy of different calcium and magnesium carbonates and we present a database of relevance in the search for life, extinct or extant, on Mars; this will be useful for the assessment of data obtained from remote, miniaturized Raman spectrometers now proposed for Mars exploration.

  7. Pathways and rates of carbon mineralization on the Eastern Siberian shelf and slope

    NASA Astrophysics Data System (ADS)

    Brüchert, Volker; Bröder, Lisa; Sawicka, Joanna; Rattray, Jayne; Gustafsson, Örjan; Samarkin, Vladimir; Tesi, Tommaso

    2016-04-01

    In recent years the Eastern Siberian Sea shelf and slope have received considerable attention because the area connects some of the largest landward organic carbon reservoirs on Earth - Arctic soil and permafrost carbon - with the ocean. Understanding mobilization and transport of organic carbon along the land-sea continuum and quantifying the burial efficiency of carbon in the seafloor are critical for quantifying the inventory of marine dissolved inorganic carbon and the exchange of CO2 with the atmosphere. We report on biomarker composition, oxygen uptake rates, sulfate reduction rates as well as porewater chemistry from 18 stations from the Laptev Sea to the Eastern Siberian Sea ranging from 40 to 3000 m water depth. Our data indicate overall low rates of aerobic and anaerobic carbon mineralization compared to other shelf and slope marine environments indicating that the deposited organic material is of overall low reactivity. Carbon mineralization rates increase eastward towards the Eastern Siberian and Chukchi Sea, in accordance with an increase in the proportion of marine-derived organic matter due to Pacific influence towards the East. From 40 to 3000 m water depth range, carbon mineralization rates decrease only by about a factor 20 from the shelf to the slope, which is significantly less than the 100- to 1000-fold decrease observed in other shelf-slope environments. These findings indicate that organic matter on the Siberian shelf and slope is already significantly degraded and efficiently buried once it is deposited after land-sea transport in the shelf and slope sediments.

  8. CO2-brine-mineral Reactions in Geological Carbon Storage: Results from an EOR Experiment

    NASA Astrophysics Data System (ADS)

    Chapman, H.; Wigley, M.; Bickle, M.; Kampman, N.; Dubacq, B.; Galy, A.; Ballentine, C.; Zhou, Z.

    2012-04-01

    Dissolution of CO2 in brines and reactions of the acid brines ultimately dissolving silicate minerals and precipitating carbonate minerals are the prime long-term mechanisms for stabilising the light supercritical CO2 in geological carbon storage. However the rates of dissolution are very uncertain as they are likely to depend on the heterogeneity of the flow of CO2, the possibility of convective instability of the denser CO2-saturated brines and on fluid-mineral reactions which buffer brine acidity. We report the results of sampling brines and gases during a phase of CO2 injection for enhanced oil recovery in a small oil field. Brines and gases were sampled at production wells daily for 3 months after initiation of CO2 injection and again for two weeks after 5 months. Noble gas isotopic spikes were detected at producing wells within days of initial CO2 injection but signals continued for weeks, and at some producers for the duration of the sampling period, attesting to the complexity of gas-species pathways. Interpretations are complicated by the previous history of the oil field and re-injection of produced water prior to injection of CO2. However water sampled from some producing wells during the phase of CO2 injection showed monotonic increases in alkalinity and in concentrations of major cations to levels in excess of those in the injected water. The marked increase in Na, and smaller increases in Ca, Mg, Si, K and Sr are interpreted primarily to result from silicate dissolution as the lack of increase in S and Cl concentrations preclude additions of more saline waters. Early calcite dissolution was followed by re-precipitation. 87Sr/86Sr ratios in the waters apparently exceed the 87Sr/86Sr ratios of acetic and hydrochloric acid leaches of carbonate fractions of the reservoir rocks and the silicate residues from the leaching. This may indicate incongruent dissolution of Sr or larger scale isotopic heterogeneity of the reservoir. This is being investigated

  9. Characterization of microbe-mineral interaction under supercritical CO2: Possible roles for bacteria during geologic carbon sequestration

    NASA Astrophysics Data System (ADS)

    Freedman, A. J.; Peet, K. C.; Ajo Franklin, J. B.; Ajo-Franklin, C.; Cappuccio, J. A.; Thompson, J. R.

    2011-12-01

    The injection of CO2 into geological formations at quantities necessary to significantly reduce CO2 emissions will represent an environmental perturbation on a continental scale. Evaluation of potential impacts at and below the surface requires a multifaceted approach that includes accurate prediction of how the CO2 behaves after injection. Microbial activity can significantly catalyze dissolution and nucleation of minerals in subsurface environments. However, the extent to which biogeochemical processes may play a role in the fate and transport of CO2 injected into geological formations has remained an open question due to the fact that at temperatures and pressures associated with reservoirs targeted for sequestration CO2 exists as a supercritical fluid (scCO2), which has generally been regarded as a sterilizing agent. To investigate whether microbial activity may mediate mineral trapping of CO2 on post-injection timescales we have developed a model system for incubating the scCO2 tolerant strain Bacillus MIT0214 (Hernandez, et al.) with minerals under scCO2 using a novel CO2 delivery apparatus. Growth of Bacillus strain MIT0214 under scCO2 (37°C at 120 atm) with a suite of index and accessory minerals associated with sandstone injection zone formations occurred at the same rate as cultures that were not exposed to mineral preparations (i.e. albite, quartz, calcite, biotite, bytownite feldspar, olivine and diopside - identified and characterized by XRD and BET). Further characterization of interactions between MIT0214 and each mineral by scanning electron microscopy and energy-dispersive x-ray spectroscopy (SEM-EDAX) sheds light on the nature of microbe-mineral contacts under scCO2 and the extent to which heterotrophic microbial activity can transform minerals under the high pCO2 conditions associated with geologic CO2 sequestration. The ability to study the dynamics of biocatalyzed mineral dissolution, alteration and nucleation (e.g. silicate weathering

  10. Micro-scale in situ characterisation of the organic and mineral composition of modern, hypersaline, photosynthetic microbial mats

    NASA Astrophysics Data System (ADS)

    Gautret, P.; Ramboz, C.; de Wit, R.; Delarue, F.; Orange, F.; Sorieul, S.; Westall, F.

    2012-04-01

    Physico-chemical and biological micro-scale environmental parameters within microbial mats formed in hypersaline conditions favour the precipitation of minerals, such as carbonates. We used optical microscopy and the technique "Fluorescence Induction Relaxation » (FIRe) to differentiate the photosynthetic activity of oxygenic photosynthesisers (cyanobacteria) from anoxygenic photosynthesisers (Chloroflexus-like bacteria, CFB) in samples obtained in 2011. After this preliminary investigation, we characterised the elemental composition of the different species of microorganisms, their extracellular substances (EPS), and the minerals precipitated on their surface. This study was made in-situ by µ-PIXE using the nuclear microprobe of the AIFIRA platform (CEN Bordeaux-Gradignan ; protons of 1.5 or 3MeV). With this microprobe it is possible to map the distribution of elements occurring in quantities down to several ppm, a resolution that is particularly favourable for studying microorganisms. SEM observation of the same zones allowed us to localise exactly the microbial structures (cells, EPS) and minerals analysed by nuclear probe. We were thus able to document the differential S and P concentrations in the different microbial species, the CLB being richer in P. Note that the CLB filaments are < 1 µm in diameter. We were also able to demonstrate the anti-correlation of Ca and Mg in the minerals precipitated directly on the microorganisms and on their EPS. Thus we have shown the utility of these in situ, nano-scale methods in studying microbial structures consisting of different species with different metabolic activitie, and different functional groups on their cell walls and EPS implicated in the bioprecipitation of different kinds of minerals. Such features in ancient microbial mats could aid their interpretation and possibly the distinction between ancient oxygenic and anoxygenic mats.

  11. [Effects of variable temperature on organic carbon mineralization in typical limestone soils].

    PubMed

    Wang, Lian-Ge; Gao, Yan-Hong; Ding, Chang-Huan; Ci, En; Xie, De-Ti

    2014-11-01

    Soil sampling in the field and incubation experiment in the laboratory were conducted to investigate the responses of soil organic carbon (SOC) mineralization to variable temperature regimes in the topsoil of limestone soils from forest land and dry land. Two incubated limestone soils were sampled from the 0-10 cm layers of typical forest land and dry land respectively, which were distributed in Tianlong Mountain area of Puding county, Guizhou province. The soils were incubated for 56 d under two different temperature regimes including variable temperature (range: 15-25 degrees C, interval: 12 h) and constant temperature (20 degrees C), and the cumulative temperature was the same in the two temperature treatments. In the entire incubation period (56 d), the SOC cumulative mineralization (63.32 mg x kg(-1)) in the limestone soil from dry land (SH) under the variable temperature was lower than that (63.96 mg x kg(-1)) at constant 20 degrees C, and there was no significant difference in the SOC cumulative mineralization between the variable and constant temperature treatments (P < 0.05). While the cumulative mineralization (169.46 mg x kg(-1)) of organic carbon in the limestone soil from forest land (SL) under the variable temperature was significantly lower than that (209.52 mg x kg(-1)) at constant 20 degrees C. The results indicated that the responses of SOC mineralization to the variable temperature were obviously different between SL and SH soils. The SOC content and composition were significantly different between SL and SH soils affected by vegetation and land use type, which suggested that SOC content and composition were important factors causing the different responses of SOC mineralization to variable temperature between SL and SH soils. In addition, the dissolved organic carbon (DOC) content of two limestone soils were highly (P < 0.01) positively correlated with daily mineralization of soil organic carbon in both temperature treatments, which implied that

  12. Mineralogy and Geochemical Processes of Carbonate Mineral-rich Sulfide Mine Tailings, Zimapan, Mexico

    NASA Astrophysics Data System (ADS)

    McClure, R. J.; Deng, Y.; Loeppert, R.; Herbert, B. E.; Carrillo, R.; Gonzalez, C.

    2009-12-01

    Mining for silver, lead, zinc, and copper in Zimapan, Hidalgo State, Mexico has been ongoing since 1576. High concentrations of heavy metals have been found in several mine tailing heaps in the Zimapan area, with concentrations of arsenic observed as high as 28,690 mg/kg and levels of Pb as high as 2772 mg/kg. Unsecured tailings heaps and associated acid mine drainage has presented tremendous problems to revegetation, water quality, and dust emission control in the Zimapan area. Although acid mine drainage problems related to weathering of sulfide minerals have been extensively studied and are well known, the weathering products of sulfides in areas with a significant presence of carbonate minerals and their effect on the mobility of heavy metals warrant further study. Carbonate minerals are expected to neutralize sulfuric acid produced from weathering of sulfide minerals, however, in the Zimapan area localized areas of pH as low as 1.8 were observed within carbonate mineral-rich tailing heaps. The objectives of this study are to characterize (1) the heavy metal-containing sulfide minerals in the initial tailing materials, (2) the intermediate oxidation products of sulfide minerals within the carbonate-rich tailings, (3) chemical species of heavy metals within pH gradients between 1.8 and 8.2, the approximate natural pH of limestone, and (4) the mobility of soluble and colloidal heavy metals and arsenic within the carbonate-rich tailings. Representative mine tailings and their intermediate oxidation products have been sampled from the Zimapan area. Mineralogical characterization will be conducted with X-ray diffraction, infrared spectroscopy, electron microscopes and microprobes, and chemical methods. Chemical species will be extracted by selective dissolution methods. Preliminary results have identified calcite as the dominant mineral in the tailing heaps with a pH of 7, suggesting non-equilibrium with the acidic weathering products. Other minerals identified in

  13. Surface materials map of Afghanistan: carbonates, phyllosilicates, sulfates, altered minerals, and other materials

    USGS Publications Warehouse

    Kokaly, Raymond F.; King, Trude V.V.; Hoefen, Todd M.; Dudek, Kathleen B.; Livo, Keith E.

    2012-01-01

    This map shows the distribution of selected carbonates, phyllosilicates, sulfates, altered minerals, and other materials derived from analysis of HyMap imaging spectrometer data of Afghanistan. Using a NASA (National Aeronautics and Space Administration) WB-57 aircraft flown at an altitude of ~15,240 meters or ~50,000 feet, 218 flight lines of data were collected over Afghanistan between August 22 and October 2, 2007. The HyMap data were converted to apparent surface reflectance, then further empirically adjusted using ground-based reflectance measurements. The reflectance spectrum of each pixel of HyMap data was compared to the spectral features of reference entries in a spectral library of minerals, vegetation, water, ice, and snow. This map shows the spatial distribution of minerals that have diagnostic absorption features in the shortwave infrared wavelengths. These absorption features result primarily from characteristic chemical bonds and mineralogical vibrations. Several criteria, including (1) the reliability of detection and discrimination of minerals using the HyMap spectrometer data, (2) the relative abundance of minerals, and (3) the importance of particular minerals to studies of Afghanistan's natural resources, guided the selection of entries in the reference spectral library and, therefore, guided the selection of mineral classes shown on this map. Minerals occurring abundantly at the surface and those having unique spectral features were easily detected and discriminated. Minerals having similar spectral features were less easily discriminated, especially where the minerals were not particularly abundant and (or) where vegetation cover reduced the absorption strength of mineral features. Complications in reflectance calibration also affected the detection and identification of minerals.

  14. Structural Stability and Mobility of Carbonate Minerals and Melts in the Earth's Mantle

    NASA Astrophysics Data System (ADS)

    Liu, J.; Caracas, R.; Fan, D.; Zhang, D.; Mao, W. L.

    2015-12-01

    Knowledge of potential carbon carriers such as the mantle carbonate minerals and melts is critical for our understanding of the deep-carbon cycle and related geological processes within the planet. Although rhombohedral carbonates (e.g., calcite, magnesite, and siderite) have been proposed as a major carbon carrier in the Earth's crust and upper mantle, several distinct scenarios have been proposed for these carbonates at deep-mantle conditions including chemical dissociation and various structural transitions. Recently, carbonate melts have been reported to be highly mobile at high pressure and temperature (P-T) conditions, which may have significant impact on magmatic processes in Earth's upper mantle. However, the high P-T behaviors of carbonate minerals and melts are still not well understood, in terms of their structural stability and mobility in the Earth's lower mantle. Combining in-situ synchrotron X-ray diffraction (XRD), transmission X-ray microscopy (TXM), and Raman spectroscopy experiments in a laser-heated diamond anvil cell with complementary theoretical calculations, we investigate the phase stability of carbonates, the equation of state (EoS) of carbonatic glasses, as well as the distribution of carbonate melts in a silicate matrix up to lower-mantle conditions.

  15. Morphological changes during enhanced carbonation of asbestos containing material and its comparison to magnesium silicate minerals.

    PubMed

    Gadikota, Greeshma; Natali, Claudio; Boschi, Chiara; Park, Ah-Hyung Alissa

    2014-01-15

    The disintegration of asbestos containing materials (ACM) over time can result in the mobilization of toxic chrysotile ((Mg, Fe)3Si2O5(OH)4)) fibers. Therefore, carbonation of these materials can be used to alter the fibrous morphology of asbestos and help mitigate anthropogenic CO2 emissions, depending on the amount of available alkaline metal in the materials. A series of high pressure carbonation experiments were performed in a batch reactor at PCO2 of 139atm using solvents containing different ligands (i.e., oxalate and acetate). The results of ACM carbonation were compared to those of magnesium silicate minerals which have been proposed to permanently store CO2 via mineral carbonation. The study revealed that oxalate even at a low concentration of 0.1M was effective in enhancing the extent of ACM carbonation and higher reaction temperatures also resulted in increased ACM carbonation. Formation of phases such as dolomite ((Ca, Mg)(CO3)2), whewellite (CaC2O4·H2O) and glushinskite (MgC2O4·2H2O) and a reduction in the chrysotile content was noted. Significant changes in the particle size and surface morphologies of ACM and magnesium silicate minerals toward non-fibrous structures were observed after their carbonation.

  16. Mineral replacements during carbonation of peridotite: implications for carbon dioxide sequestration in ultramafic rocks

    NASA Astrophysics Data System (ADS)

    Beinlich, Andreas; Hövelmann, Jörn; Plümper, Oliver; Austrheim, Hâkon

    2010-05-01

    , together with poorly crystalline serpentine and extremely fine grained talc. Hydrothermal batch experiments (130-160 bar PCO2; 200° C; 1-3 weeks reaction time) show that the alteration product after olivine is the favorable site of reaction presumably due to the large reactive surface area. In contrast, the olivine relicts have reacted to a significantly lesser extend, whereas the serpentine veins remain virtually unreacted. The dissolution of the compartment fillings is followed by nucleation and growth of calcite crystals also revealing that precipitation of calcite is strongly favored over magnesite as soon as the system contains Ca. The preferred precipitation of calcite is also supported by geochemical modeling (using Phreeqc), which shows that the Mg-bearing carbonates (dolomite, magnesite) only form if the fluid is sufficiently depleted in Ca. The compositional and textural differences between different samples as well as different run products from experiments indicate that the described clasts evolved from peridotite due to extreme mobilization of Mg, development of secondary porosity, and infill of carbonates. Mg removed from the clasts is partly consumed by replacement reactions in the vicinity of the clasts where Fe-minerals (almandine) are altered to Mg-minerals (talc). For basins containing abundant peridotite clasts, the outlined process will influence the CO2 and MgO budget. References: IPCC Special report: Carbon Dioxide Capture and Storage, Summary for Policymakers, 2005.

  17. Mineral carbonation: energy costs of pretreatment options and insights gained from flow loop reaction studies

    SciTech Connect

    Penner, Larry R.; O'Connor, William K.; Dahlin, David C.; Gerdemann, Stephen J.; Rush, Gilbert E.

    2004-01-01

    Sequestration of carbon as a stable mineral carbonate has been proposed to mitigate environmental concerns that carbon dioxide may with time escape from its sequestered matrix using alternative sequestration technologies. A method has been developed to prepare stable carbonate products by reacting CO2 with magnesium silicate minerals in aqueous bicarbonate/chloride media at high temperature and pressure. Because this approach is inherently expensive due to slow reaction rates and high capital costs, studies were conducted to improve the reaction rates through mineral pretreatment steps and to cut expenses through improved reactor technology. An overview is given for the estimated cost of the process including sensitivity to grinding and heating as pretreatment options for several mineral feedstocks. The energy costs are evaluated for each pretreatment in terms of net carbon avoided. New studies with a high-temperature, high-pressure flow-loop reactor have yielded information on overcoming kinetic barriers experienced with processing in stirred autoclave reactors. Repeated tests with the flow-loop reactor have yielded insights on wear and failure of system components, on challenges to maintain and measure flow, and for better understanding of the reaction mechanism.

  18. Fundamental study of CO2-H2O-mineral interactions for carbon sequestration, with emphasis on the nature of the supercritical fluid-mineral interface.

    SciTech Connect

    Bryan, Charles R.; Dewers, Thomas A.; Heath, Jason E.; Wang, Yifeng; Matteo, Edward N.; Meserole, Stephen P.; Tallant, David Robert

    2013-09-01

    In the supercritical CO2-water-mineral systems relevant to subsurface CO2 sequestration, interfacial processes at the supercritical fluid-mineral interface will strongly affect core- and reservoir-scale hydrologic properties. Experimental and theoretical studies have shown that water films will form on mineral surfaces in supercritical CO2, but will be thinner than those that form in vadose zone environments at any given matric potential. The theoretical model presented here allows assessment of water saturation as a function of matric potential, a critical step for evaluating relative permeabilities the CO2 sequestration environment. The experimental water adsorption studies, using Quartz Crystal Microbalance and Fourier Transform Infrared Spectroscopy methods, confirm the major conclusions of the adsorption/condensation model. Additional data provided by the FTIR study is that CO2 intercalation into clays, if it occurs, does not involve carbonate or bicarbonate formation, or significant restriction of CO2 mobility. We have shown that the water film that forms in supercritical CO2 is reactive with common rock-forming minerals, including albite, orthoclase, labradorite, and muscovite. The experimental data indicate that reactivity is a function of water film thickness; at an activity of water of 0.9, the greatest extent of reaction in scCO2 occurred in areas (step edges, surface pits) where capillary condensation thickened the water films. This suggests that dissolution/precipitation reactions may occur preferentially in small pores and pore throats, where it may have a disproportionately large effect on rock hydrologic properties. Finally, a theoretical model is presented here that describes the formation and movement of CO2 ganglia in porous media, allowing assessment of the effect of pore size and structural heterogeneity on capillary trapping efficiency. The model results also suggest possible engineering approaches for optimizing trapping capacity and for

  19. Microbial Contribution to Organic Carbon Sequestration in Mineral Soil

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Soil productivity and sustainability are dependent on soil organic matter (SOM). Our understanding on how organic inputs to soil from microbial processes become converted to SOM is still limited. This study aims to understand how microbes affect carbon (C) sequestration and the formation of recalcit...

  20. Nanoanalytical Electron Microscopy Reveals a Sequential Mineralization Process Involving Carbonate-Containing Amorphous Precursors.

    PubMed

    Nitiputri, Kharissa; Ramasse, Quentin M; Autefage, Hélène; McGilvery, Catriona M; Boonrungsiman, Suwimon; Evans, Nicholas D; Stevens, Molly M; Porter, Alexandra E

    2016-07-26

    A direct observation and an in-depth characterization of the steps by which bone mineral nucleates and grows in the extracellular matrix during the earliest stages of maturation, using relevant biomineralization models as they grow into mature bone mineral, is an important research goal. To better understand the process of bone mineralization in the extracellular matrix, we used nanoanalytical electron microscopy techniques to examine an in vitro model of bone formation. This study demonstrates the presence of three dominant CaP structures in the mineralizing osteoblast cultures: <80 nm dense granules with a low calcium to phosphate ratio (Ca/P) and crystalline domains; calcium phosphate needles emanating from a focus: "needle-like globules" (100-300 nm in diameter) and mature mineral, both with statistically higher Ca/P compared to that of the dense granules. Many of the submicron granules and globules were interspersed around fibrillar structures containing nitrogen, which are most likely the signature of the organic phase. With high spatial resolution electron energy loss spectroscopy (EELS) mapping, spatially resolved maps were acquired showing the distribution of carbonate within each mineral structure. The carbonate was located in the middle of the granules, which suggested the nucleation of the younger mineral starts with a carbonate-containing precursor and that this precursor may act as seed for growth into larger, submicron-sized, needle-like globules of hydroxyapatite with a different stoichiometry. Application of analytical electron microscopy has important implications in deciphering both how normal bone forms and in understanding pathological mineralization. PMID:27383526

  1. An economic analysis of the Jim Bridger Power Plant carbon dioxide mineralization process

    NASA Astrophysics Data System (ADS)

    Christensen, Mikol Hans

    Concerns for rising levels of CO2 in the atmosphere have lead to a myriad of schemes to reduce emissions. Many of these are complicated, expensive, and untried. Coal-fired electrical generation accounts for about 49 percent of U.S. electricity generation. Shifting generation capacity away from coal is the goal of many, yet as this statistic shows, the U.S. has a heavy dependency on coal-fired base-load generation. What is needed is a way to retrofit existing coal fired power plants to mitigate at least some of the giga-tonnes of CO2 released annually. Carbon Capture and Storage in association with greenhouse gases are a major concern in the world today. This thesis is an outgrowth of a research partnership between the University of Wyoming and the Jim Bridger Power Plant (Rocky Mountain Power) to develop a process for capture and mineralization of flue gas carbon dioxide (CO 2) using an accelerated mineral carbonization process with fly ash particles as the absorbent. This process may have several advantages over other approaches because it is an environmentally acceptable, single step process occurring at near ambient pressures and temperatures that can compliment conventional CCS processes. In addition the use of fly ash particles as an absorbent avoids the costs of processing or engineering an absorbent. The purpose of this thesis is to evaluate the capture costs and economic feasibility of the mineralization process. Two models were used to estimate the capture costs and economic feasibility of the Jim Bridger Power Plant CO2 Mineralization Project (JBP). The first was a cost of capture model which was used to estimate CO2 capture costs and how changes in the CO2 to ash capture ratio and quantities of CO2 captured affect capture costs. The second was a financial feasibility model which considered the time value of money. This second model considered the net present value (NPV) and internal rate of return (IRR) for the process using different pricing scenarios

  2. DEVELOPMENT OF A CO2 SEQUESTRATION MODULE BY INTEGRATING MINERAL ACTIVATION AND AQUEOUS CARBONATION

    SciTech Connect

    M. Mercedes Maroto-Valer; John M. Andresen; George Alexander

    2004-11-15

    Mineral carbonation is a promising concept for permanent CO{sub 2} sequestration due to the vast natural abundance of the raw minerals, the permanent storage of CO{sub 2} in solid form as carbonates, and the overall reaction being exothermic. However, the primary drawback to mineral carbonation is the reaction kinetics. To accelerate the reaction, aqueous carbonation processes are preferred, where the minerals are firstly dissolved in solution. In aqueous carbonation, the key step is the dissolution rate of the mineral, where the mineral dissolution reaction is likely to be surface controlled. In order to accelerate the dissolution process, the serpentine can be ground to very fine particle size (<37 {micro}m), but this is a very energy intensive process. Alternatively, magnesium could be chemically extracted in aqueous solution. Phase I showed that chemical surface activation helps to dissolve the magnesium from the serpentine minerals (particle size {approx}100 {micro}m), and furthermore, the carbonation reaction can be conducted under mild conditions (20 C and 650 psig) compared to previous studies that required >185 C, >1850 psig and <37 {micro}m particle size. Phase I also showed that over 70% of the magnesium can be extracted at ambient temperature leaving amorphous SiO{sub 2} with surface areas {approx} 330m{sup 2}/g. The overall objective of Phase 2 of this research program is to optimize the active carbonation process developed in Phase I in order to design an integrated CO{sub 2} sequestration module. During the current reporting period, Task 1 ''Mineral activation'' was initiated and focused on a parametric study to optimize the operation conditions for the mineral activation, where serpentine and sulfuric acid were reacted, as following the results from Phase 1. Several experimental factors were outlined as having a potential influence on the mineral activation. This study has focused to date on the effects of varying the acid concentration, particle

  3. Beyond temperature: Clumped isotope signatures in dissolved inorganic carbon species and the influence of solution chemistry on carbonate mineral composition

    NASA Astrophysics Data System (ADS)

    Tripati, Aradhna K.; Hill, Pamela S.; Eagle, Robert A.; Mosenfelder, Jed L.; Tang, Jianwu; Schauble, Edwin A.; Eiler, John M.; Zeebe, Richard E.; Uchikawa, Joji; Coplen, Tyler B.; Ries, Justin B.; Henry, Drew

    2015-10-01

    "Clumped-isotope" thermometry is an emerging tool to probe the temperature history of surface and subsurface environments based on measurements of the proportion of 13C and 18O isotopes bound to each other within carbonate minerals in 13C18O16O22- groups (heavy isotope "clumps"). Although most clumped isotope geothermometry implicitly presumes carbonate crystals have attained lattice equilibrium (i.e., thermodynamic equilibrium for a mineral, which is independent of solution chemistry), several factors other than temperature, including dissolved inorganic carbon (DIC) speciation may influence mineral isotopic signatures. Therefore we used a combination of approaches to understand the potential influence of different variables on the clumped isotope (and oxygen isotope) composition of minerals. We conducted witherite precipitation experiments at a single temperature and at varied pH to empirically determine 13C-18O bond ordering (Δ47) and δ18O of CO32- and HCO3- molecules at a 25 °C equilibrium. Ab initio cluster models based on density functional theory were used to predict equilibrium 13C-18O bond abundances and δ18O of different DIC species and minerals as a function of temperature. Experiments and theory indicate Δ47 and δ18O compositions of CO32- and HCO3- ions are significantly different from each other. Experiments constrain the Δ47-δ18O slope for a pH effect (0.011 ± 0.001; 12 ⩾ pH ⩾ 7). Rapidly-growing temperate corals exhibit disequilibrium mineral isotopic signatures with a Δ47-δ18O slope of 0.011 ± 0.003, consistent with a pH effect. Our theoretical calculations for carbonate minerals indicate equilibrium lattice calcite values for Δ47 and δ18O are intermediate between HCO3- and CO32-. We analyzed synthetic calcites grown at temperatures ranging from 0.5 to 50 °C with and without the enzyme carbonic anhydrase present. This enzyme catalyzes oxygen isotopic exchange between DIC species and is present in many natural systems. The two

  4. Microbially enhanced carbon capture and storage by mineral-trapping and solubility-trapping.

    PubMed

    Mitchell, Andrew C; Dideriksen, Knud; Spangler, Lee H; Cunningham, Alfred B; Gerlach, Robin

    2010-07-01

    The potential of microorganisms for enhancing carbon capture and storage (CCS) via mineral-trapping (where dissolved CO(2) is precipitated in carbonate minerals) and solubility trapping (as dissolved carbonate species in solution) was investigated. The bacterial hydrolysis of urea (ureolysis) was investigated in microcosms including synthetic brine (SB) mimicking a prospective deep subsurface CCS site with variable headspace pressures [p(CO(2))] of (13)C-CO(2). Dissolved Ca(2+) in the SB was completely precipitated as calcite during microbially induced hydrolysis of 5-20 g L(-1) urea. The incorporation of carbonate ions from (13)C-CO(2) ((13)C-CO(3)(2-)) into calcite increased with increasing p((13)CO(2)) and increasing urea concentrations: from 8.3% of total carbon in CaCO(3) at 1 g L(-1) to 31% at 5 g L(-1), and 37% at 20 g L(-1). This demonstrated that ureolysis was effective at precipitating initially gaseous [CO(2)(g)] originating from the headspace over the brine. Modeling the change in brine chemistry and carbonate precipitation after equilibration with the initial p(CO(2)) demonstrated that no net precipitation of CO(2)(g) via mineral-trapping occurred, since urea hydrolysis results in the production of dissolved inorganic carbon. However, the pH increase induced by bacterial ureolysis generated a net flux of CO(2)(g) into the brine. This reduced the headspace concentration of CO(2) by up to 32 mM per 100 mM urea hydrolyzed because the capacity of the brine for carbonate ions was increased, thus enhancing the solubility-trapping capacity of the brine. Together with the previously demonstrated permeability reduction of rock cores at high pressure by microbial biofilms and resilience of biofilms to supercritical CO(2), this suggests that engineered biomineralizing biofilms may enhance CCS via solubility-trapping, mineral formation, and CO(2)(g) leakage reduction.

  5. CO2 storage in solid form: a study of direct mineral carbonation

    SciTech Connect

    O'Connor, William K.; Dahlin, David C.; Nilsen, David N.; Rush, G.E.; Walters, Richard P.; Turner, Paul C.

    2000-01-01

    Direct mineral carbonation by an ex-situ process in an aqueous system has been investigated over the past two years. The process utilizes a slurry of water mixed with a magnesium silicate mineral, such as olivine [forsterite end member (Mg2SiO4)], or serpentine [Mg3Si2O5(OH)4]. This slurry is reacted with sub- or supercritical carbon dioxide (CO2) to produce magnesite (MgCO3). The CO2 is dissolved in water to form carbonic acid (H2CO3), which dissociates to H+ and HCO3-. The H+ ion hydrolyzes the mineral, liberating Mg2+ cations which react with the bicarbonate to form the solid carbonate. Results of the baseline tests, conducted on ground products of the natural minerals, have demonstrated that the kinetics of the reaction are slow at ambient temperature (22 C) and subcritical CO2 pressures (below 73 atm). However, at elevated temperature and pressure, coupled with continuous stirring of the slurry and gas dispersion within the water column, significant conversion to the carbonate occurs. Extent of reaction is roughly 90% within 24 hours, at 185 C and partial pressure of CO2 (PCO2) of 115 atm. Heat pretreatment of the serpentine, coupled with bicarbonate and salt additions to the solution, improve reaction kinetics, resulting in an extent of reaction of roughly 80% within 0.5 hours, at 155 C and PCO2 of 185 atm. Subsequent tests are intended to examine various pretreatment options, the carbonation solution characteristics, as well as other mineral groups.

  6. On the neutralization of acid rock drainage by carbonate and silicate minerals

    NASA Astrophysics Data System (ADS)

    Sherlock, E. J.; Lawrence, R. W.; Poulin, R.

    1995-02-01

    The net result of acid-generating and-neutralizing reactions within mining wastes is termed acid rock drainage (ARD). The oxidation of sulfide minerals is the major contributor to acid generation. Dissolution and alteration of various minerals can contribute to the neutralization of acid. Definitions of alkalinity, acidity, and buffer capacity are reviewed, and a detailed discussion of the dissolution and neutralizing capacity of carbonate and silicate minerals related to equilibium conditions, dissolution mechanism, and kinetics is provided. Factors that determine neutralization rate by carbonate and silicate minerals include: pH, PCO 2, equilibrium conditions, temperature, mineral composition and structure, redox conditions, and the presence of “foreign” ions. Similar factors affect sulfide oxidation. Comparison of rates shows sulfides react fastest, followed by carbonates and silicates. The differences in the reaction mechanisms and kinetics of neutralization have important implications in the prediction, control, and regulation of ARD. Current static and kinetic prediction methods upon which mine permitting, ARD control, and mine closure plans are based do not consider sample mineralogy or the kinetics of the acid-generating and-neutralizing reactions. Erroneous test interpretations and predictions can result. The importance of considering mineralogy for site-specific interpretation is highlighted. Uncertainty in prediction leads to difficulties for the mine operator in developing satisfactory and cost-effective control and remediation measures. Thus, the application of regulations and guidelines for waste management planning need to beflexible.

  7. A cryogenic fluorescence spectroscopic study of uranyl carbonate, phosphate, and oxyhydroxide minerals

    SciTech Connect

    Wang, Zheming; Zachara, John M.; Liu, Chongxuan; Gassman, Paul L.; Felmy, Andrew R.; Clark, Sue B.

    2008-11-03

    In this work we have applied liquid-helium temperature (LHeT) time-resolved laser-induced fluorescence spectroscopy (TRLIF) to characterize a series of natural and synthetic minerals of uranium carbonate, phosphate and oxyhydroxides including rutherfordine, zellerite, liebigite, phosphuranylite, meta-autunite, meta-torbernite, uranyl phosphate, sodium-uranyl-phosphate, bequerelite, clarkeite, curite, schoepite and compregnacite, and compared their spectral characteristics among these minerals as well as our previously published data on uranyl silicates. For the carbonate minerals, the fluorescence spectra depend on the stoichiometry of the mineral. For the phosphate minerals the fluorescence spectra closely resemble each other despite the differences in their composition and structure. For all uranium oxyhydroxides, the fluorescence spectra are largely red-shifted as compared with those of the uranium carbonates and phosphates and their vibronic bands are broadened and less resolved. The much enhanced spectra resolution at LHeT allows more accurate calculation of the O=U=O symmetrical stretch frequency, ν1, corresponding to the average spacing of the vibronic peaks of the fluorescence spectra and the spectral origin as reflected by the position of the first vibronic band. It was found that both the average ν1 and λ1 values correlate well with the average basicity of the inorganic anion.

  8. Microbially Accelerated Carbonate Mineral Precipitation as a Strategy for in Situ Carbon Sequestration and Rehabilitation of Asbestos Mine Sites.

    PubMed

    McCutcheon, Jenine; Wilson, Siobhan A; Southam, Gordon

    2016-02-01

    A microbially accelerated process for the precipitation of carbonate minerals was implemented in a sample of serpentinite mine tailings collected from the abandoned Woodsreef Asbestos Mine in New South Wales, Australia as a strategy to sequester atmospheric CO2 while also stabilizing the tailings. Tailings were leached using sulfuric acid in reaction columns and subsequently inoculated with an alkalinity-generating cyanobacteria-dominated microbial consortium that was enriched from pit waters at the Woodsreef Mine. Leaching conditions that dissolved 14% of the magnesium from the serpentinite tailings while maintaining circumneutral pH (1800 ppm, pH 6.3) were employed in the experiment. The mineralogy, water chemistry, and microbial colonization of the columns were characterized following the experiment. Micro-X-ray diffraction was used to identify carbonate precipitates as dypingite [Mg5(CO3)4(OH)2·5H2O] and hydromagnesite [Mg5(CO3)4(OH)2·4H2O] with minor nesquehonite (MgCO3·3H2O). Scanning electron microscopy revealed that carbonate mineral precipitates form directly on the filamentous cyanobacteria. These findings demonstrate the ability of these organisms to generate localized supersaturating microenvironments of high concentrations of adsorbed magnesium and photosynthetically generated carbonate ions while also acting as nucleation sites for carbonate precipitation. This study is the first step toward implementing in situ carbon sequestration in serpentinite mine tailings via microbial carbonate precipitation reactions.

  9. Microbially Accelerated Carbonate Mineral Precipitation as a Strategy for in Situ Carbon Sequestration and Rehabilitation of Asbestos Mine Sites.

    PubMed

    McCutcheon, Jenine; Wilson, Siobhan A; Southam, Gordon

    2016-02-01

    A microbially accelerated process for the precipitation of carbonate minerals was implemented in a sample of serpentinite mine tailings collected from the abandoned Woodsreef Asbestos Mine in New South Wales, Australia as a strategy to sequester atmospheric CO2 while also stabilizing the tailings. Tailings were leached using sulfuric acid in reaction columns and subsequently inoculated with an alkalinity-generating cyanobacteria-dominated microbial consortium that was enriched from pit waters at the Woodsreef Mine. Leaching conditions that dissolved 14% of the magnesium from the serpentinite tailings while maintaining circumneutral pH (1800 ppm, pH 6.3) were employed in the experiment. The mineralogy, water chemistry, and microbial colonization of the columns were characterized following the experiment. Micro-X-ray diffraction was used to identify carbonate precipitates as dypingite [Mg5(CO3)4(OH)2·5H2O] and hydromagnesite [Mg5(CO3)4(OH)2·4H2O] with minor nesquehonite (MgCO3·3H2O). Scanning electron microscopy revealed that carbonate mineral precipitates form directly on the filamentous cyanobacteria. These findings demonstrate the ability of these organisms to generate localized supersaturating microenvironments of high concentrations of adsorbed magnesium and photosynthetically generated carbonate ions while also acting as nucleation sites for carbonate precipitation. This study is the first step toward implementing in situ carbon sequestration in serpentinite mine tailings via microbial carbonate precipitation reactions. PMID:26720600

  10. Mineral Sequestration of Carbon Dixoide in a Sandstone-Shale System

    SciTech Connect

    Xu, Tianfu; Apps, John A.; Pruess, Karsten

    2004-07-09

    A conceptual model of CO2 injection in bedded sandstone-shale sequences has been developed using hydrogeologic properties and mineral compositions commonly encountered in Gulf Coast sediments. Numerical simulations were performed with the reactive fluid flow and geochemical transport code TOUGHREACT to analyze mass transfer between sandstone and shale layers and CO2 immobilization through carbonate precipitation. Results indicate that most CO2 sequestration occurs in the sandstone. The major CO2 trapping minerals are dawsonite and ankerite. The CO2 mineral-trapping capacity after 100,000 years reaches about 90 kg per cubic meter of the medium. The CO2 trapping capacity depends on primary mineral composition. Precipitation of siderite and ankerite requires Fe+2 supplied mainly by chlorite and some by hematite dissolution and reduction. Precipitation of dawsonite requires Na+ provided by oligoclase dissolution. The initial abundance of chlorite and oligoclase therefore affects the CO2 mineral trapping capacity. The sequestration time required depends on the kinetic rate of mineral dissolution and precipitation. Dawsonite reaction kinetics is not well understood, and sensitivity regarding the precipitation rate was examined. The addition of CO2 as secondary carbonates results in decreased porosity. The leaching of chemical constituents from the interior of the shale causes slightly increased porosity. The limited information currently available for the mineralogy of natural high-pressure CO2 gas reservoirs is also generally consistent with our simulation. The ''numerical experiments'' give a detailed understanding of the dynamic evolution of a sandstone-shale geochemical system.

  11. Carbon Mineralization in Two Ultisols Amended with Different Sources and Particle Sizes of Pyrolyzed Biochar

    EPA Science Inventory

    Biochar produced during pyrolysis has the potential to enhance soil fertility and reduce greenhouse gas emissions. The influence of biochar properties (e.g., particle size) on both short- and long-term carbon (C) mineralization of biochar remains unclear. There is minimal informa...

  12. A rapid and cost effective method for soil carbon mineralization under static incubations

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Soil incubations with subsequent measurement of carbon dioxide (CO2) evolved are common soil assays to estimate C mineralization rates and active organic C. Two common methods used to detect CO2 in laboratory incubations are gas chromatography (GC) and alkali absorption followed by titration (NaOH)...

  13. CO2 mitigation potential of mineral carbonation with industrial alkalinity sources in the United States.

    PubMed

    Kirchofer, Abby; Becker, Austin; Brandt, Adam; Wilcox, Jennifer

    2013-07-01

    The availability of industrial alkalinity sources is investigated to determine their potential for the simultaneous capture and sequestration of CO2 from point-source emissions in the United States. Industrial alkalinity sources investigated include fly ash, cement kiln dust, and iron and steel slag. Their feasibility for mineral carbonation is determined by their relative abundance for CO2 reactivity and their proximity to point-source CO2 emissions. In addition, the available aggregate markets are investigated as possible sinks for mineral carbonation products. We show that in the U.S., industrial alkaline byproducts have the potential to mitigate approximately 7.6 Mt CO2/yr, of which 7.0 Mt CO2/yr are CO2 captured through mineral carbonation and 0.6 Mt CO2/yr are CO2 emissions avoided through reuse as synthetic aggregate (replacing sand and gravel). The emission reductions represent a small share (i.e., 0.1%) of total U.S. CO2 emissions; however, industrial byproducts may represent comparatively low-cost methods for the advancement of mineral carbonation technologies, which may be extended to more abundant yet expensive natural alkalinity sources. PMID:23738892

  14. Quantitative identification of metastable magnesium carbonate minerals by solid-state 13C NMR spectroscopy.

    PubMed

    Moore, Jeremy K; Surface, J Andrew; Brenner, Allison; Wang, Louis S; Skemer, Philip; Conradi, Mark S; Hayes, Sophia E

    2015-01-01

    In the conversion of CO2 to mineral carbonates for the permanent geosequestration of CO2, there are multiple magnesium carbonate phases that are potential reaction products. Solid-state (13)C NMR is demonstrated as an effective tool for distinguishing magnesium carbonate phases and quantitatively characterizing magnesium carbonate mixtures. Several of these mineral phases include magnesite, hydromagnesite, dypingite, and nesquehonite, which differ in composition by the number of waters of hydration or the number of crystallographic hydroxyl groups. These carbonates often form in mixtures with nearly overlapping (13)C NMR resonances which makes their identification and analysis difficult. In this study, these phases have been investigated with solid-state (13)C NMR spectroscopy, including both static and magic-angle spinning (MAS) experiments. Static spectra yield chemical shift anisotropy (CSA) lineshapes that are indicative of the site-symmetry variations of the carbon environments. MAS spectra yield isotropic chemical shifts for each crystallographically inequivalent carbon and spin-lattice relaxation times, T1, yield characteristic information that assist in species discrimination. These detailed parameters, and the combination of static and MAS analyses, can aid investigations of mixed carbonates by (13)C NMR.

  15. Mineral saturation and scaling tendencies of waters discharged from wells (>150 şC) in geothermal areas of Turkey

    NASA Astrophysics Data System (ADS)

    Tarcan, Gültekin

    2005-04-01

    Aqueous species distribution was calculated from the chemical composition of water discharges from 27 selected production wells, with reservoir temperatures >150 şC, in seven geothermal areas including Kızıldere, Salavatlı, Germencik, Kavaklıdere-Sazdere, Salihli-Caferbeyli, Simav, and Tuzla. Twenty-five of the water compositions are relatively dilute with electroconductivity values of 1826 to 7200 μS/cm and are dominated by Na (410 to 2027 mg/kg), Cl (45 to 1882 mg/kg), and alkalinity-CO 2 (491 to 2312 mg/kg). Two water samples from Tuzla are highly saline connate waters with Cl of 35 273 to 44 140 mg/kg and Na of 18 200 to 22 250 mg/kg. Mineral equilibrium modeling indicates that the aquifer waters in these selected geothermal wells, with some exceptions, are oversaturated with respect to calcite, aragonite, and celestite, but undersaturated with respect to gypsum, anhydrite, fluorite, Ca-montmorillonite, anorthite, albite-low, gibbsite, illite, kaolinite, and K-feldspar. The waters are at near saturation with respect to chalcedony, quartz, amorphous silica, dolomite, and strontianite. Calculation of mineral saturation states, geochemical studies, and field observations show that carbonate minerals (calcite, aragonite, and dolomite), amorphous silica, and sulfate minerals (celestite and anhydrite) are most likely to be precipitated as scales in geothermal wells. Assessment of calcite and amorphous silica scaling tendencies for selected well waters indicates that hot injection is favorable for Tuzla well T-2 (˜50-170 şC) and for Kızıldere wells R-1 and KD-6 (around 100 şC). For the other wells, cold injection (<50 şC) is favored if calcite and amorphous silica accumulation is to be avoided in injection wells.

  16. Tree-mycorrhiza symbiosis accelerate mineral weathering: Evidences from nanometer-scale elemental fluxes at the hypha-mineral interface

    NASA Astrophysics Data System (ADS)

    Bonneville, Steeve; Morgan, Daniel J.; Schmalenberger, Achim; Bray, Andrew; Brown, Andrew; Banwart, Steven A.; Benning, Liane G.

    2011-11-01

    In soils, mycorrhiza (microscopic fungal hypha) living in symbiosis with plant roots are the biological interface by which plants obtain, from rocks and organic matter, the nutrients necessary for their growth and maintenance. Despite their central role in soils, the mechanism and kinetics of mineral alteration by mycorrhiza are poorly constrained quantitatively. Here, we report in situ quantification of weathering rates from a mineral substrate, (0 0 1) basal plane of biotite, by a surface-bound hypha of Paxillus involutus, grown in association with the root system of a Scots pine, Pinus sylvestris. Four thin-sections were extracted by focused ion beam (FIB) milling along a single hypha grown over the biotite surface. Depth-profile of Si, O, K, Mg, Fe and Al concentrations were performed at the hypha-biotite interface by scanning transmission electron microscopy-energy dispersive X-ray spectroscopy (STEM-EDX). Large removals of K (50-65%), Mg (55-75%), Fe (80-85%) and Al (75-85%) were observed in the topmost 40 nm of biotite underneath the hypha while Si and O are preserved throughout the depth-profile. A quantitative model of alteration at the hypha-scale was developed based on solid-state diffusion fluxes of elements into the hypha and the break-down/mineralogical re-arrangement of biotite. A strong acidification was also observed with hypha bound to the biotite surface reaching pH < 4.6. When consistently compared with the abiotic biotite dissolution, we conclude that the surface-bound mycorrhiza accelerate the biotite alteration kinetics between pH 3.5 and 5.8 to ˜0.04 μmol biotite m -2 h -1. Our current work reaffirms that fungal mineral alteration is a process that combines our previously documented bio-mechanical forcing with the μm-scale acidification mediated by surface-bound hypha and a subsequent chemical element removal due to the fungal action. As such, our study presents a first kinetic framework for mycorrhizal alteration at the hypha-scale under

  17. Development of a CO2 Sequestration Module by Integrating Mineral Activation and Aqueous Carbonation

    SciTech Connect

    George Alexander; Parvana Aksoy; John Andresen; Mercedes Maroto-Valer; Harold Schobert

    2006-08-14

    Mineral carbonation is a promising concept for permanent CO{sub 2} sequestration due to the vast natural abundance of the raw materials and the permanent storage of CO{sub 2} in solid form as carbonates. The sequestration of CO{sub 2} through the employment of magnesium silicates--olivine and serpentine--is beyond the proof of concept stage. For the work done in this project, serpentine was chosen as the feedstock mineral due to its abundance and availability. Although the reactivity of olivine is greater than that of serpentine, physical and chemical treatments have been shown to increase greatly the reactivity of serpentine. The primary drawback to mineral carbonation is reaction kinetics. To accelerate the carbonation, aqueous processes are preferred, where the minerals are first dissolved in solution. In aqueous carbonation, the key step is the dissolution rate of the mineral, where the mineral dissolution reaction is likely to be surface-controlled. The relatively low reactivity of serpentine has warranted research into physical and chemical treatments that have been shown to greatly increase its reactivity. The use of sulfuric acid as an accelerating medium for the removal of magnesium from serpentine has been investigated. To accelerate the dissolution process, the mineral can be ground to very fine particle size, <37 {micro}m, but this is a very energy-intensive process. Previous work in our laboratory showed that chemical surface activation helps to dissolve magnesium from the serpentine (of particle size {approx} 100 {micro}m) and that the carbonation reaction can be conducted under mild conditions (20 C and 4.6 MPa) compared to previous studies that required >185 C, >13 MPa, and <37 {micro}m particle size. This work also showed that over 70% of the magnesium can be extracted at ambient temperature, leaving an amorphous silica with surface area of about 330 m{sup 2}/g. The overall objective of this research program is to optimize the active carbonation

  18. Predicting long-term carbon mineralization and trace gas production from thawing permafrost of Northeast Siberia.

    PubMed

    Knoblauch, Christian; Beer, Christian; Sosnin, Alexander; Wagner, Dirk; Pfeiffer, Eva-Maria

    2013-04-01

    The currently observed Arctic warming will increase permafrost degradation followed by mineralization of formerly frozen organic matter to carbon dioxide (CO2 ) and methane (CH4 ). Despite increasing awareness of permafrost carbon vulnerability, the potential long-term formation of trace gases from thawing permafrost remains unclear. The objective of the current study is to quantify the potential long-term release of trace gases from permafrost organic matter. Therefore, Holocene and Pleistocene permafrost deposits were sampled in the Lena River Delta, Northeast Siberia. The sampled permafrost contained between 0.6% and 12.4% organic carbon. CO2 and CH4 production was measured for 1200 days in aerobic and anaerobic incubations at 4 °C. The derived fluxes were used to estimate parameters of a two pool carbon degradation model. Total CO2 production was similar in Holocene permafrost (1.3 ± 0.8 mg CO2 -C gdw(-1) aerobically, 0.25 ± 0.13 mg CO2 -C gdw(-1) anaerobically) as in 34 000-42 000-year-old Pleistocene permafrost (1.6 ± 1.2 mg CO2 -C gdw(-1) aerobically, 0.26 ± 0.10 mg CO2 -C gdw(-1) anaerobically). The main predictor for carbon mineralization was the content of organic matter. Anaerobic conditions strongly reduced carbon mineralization since only 25% of aerobically mineralized carbon was released as CO2 and CH4 in the absence of oxygen. CH4 production was low or absent in most of the Pleistocene permafrost and always started after a significant delay. After 1200 days on average 3.1% of initial carbon was mineralized to CO2 under aerobic conditions while without oxygen 0.55% were released as CO2 and 0.28% as CH4 . The calibrated carbon degradation model predicted cumulative CO2 production over a period of 100 years accounting for 15.1% (aerobic) and 1.8% (anaerobic) of initial organic carbon, which is significantly less than recent estimates. The multiyear time series from the incubation experiments helps to more reliably constrain projections of future

  19. [Effects of different types of litters on soil organic carbon mineralization].

    PubMed

    Shi, Xue-Jun; Pan, Jian-Jun; Chen, Jin-Ying; Yang, Zhi-Qiang; Zhang, Li-Ming; Sun, Bo; Li, Zhong-Pei

    2009-06-15

    Using litter incubation experiment in laboratory, decomposition discrepancies of four typical litters from Zijin Mountain were analyzed. The results show that organic carbon mineralization rates of soil with litters all involve fast and slow decomposition stages, and the differences are that the former has shorter duration,more daily decomposition quantity while the latter is opposite. Organic carbon mineralization rates of soil with litters rapidly reached maximum in the early days of incubation, and the order is soil with Cynodon dactylon litter (CK + BMD) (23.88 +/- 0.62) mg x d(-1), soil with Pinus massoniana litter (CK+ PML) (17.93 +/- 0.99) mg x d(-1), soil with Quercus acutissima litter (CK+ QAC) (15.39 +/- 0.16) mg x d(-1) and soil with Cyclobalanopsis glauca litter (CK + CGO) (7.26 +/- 0.34) mg x d(-1), and with significant difference between each other (p < 0.05). This order has not significant correlation to litter initial chemical elements. The amount of organic carbon mineralized accumulation within three months incubation is (CK + BMD) (338.21 +/- 6.99) mg, (CK + QAC) (323.48 +/- 13.68) mg, (CK + PML) (278.34 +/- 13.91) mg and (CK + CGO) (245.21 +/- 4.58) mg. 198.17-297.18 mg CO2-C are released during litter incubation, which occupies 20.29%-31.70% of the total litter organic carbon amounts. Power curve model can describe the trends of organic carbon mineralization rate and mineralized accumulation amount,which has a good correlation with their change. PMID:19662876

  20. [Effects of different types of litters on soil organic carbon mineralization].

    PubMed

    Shi, Xue-Jun; Pan, Jian-Jun; Chen, Jin-Ying; Yang, Zhi-Qiang; Zhang, Li-Ming; Sun, Bo; Li, Zhong-Pei

    2009-06-15

    Using litter incubation experiment in laboratory, decomposition discrepancies of four typical litters from Zijin Mountain were analyzed. The results show that organic carbon mineralization rates of soil with litters all involve fast and slow decomposition stages, and the differences are that the former has shorter duration,more daily decomposition quantity while the latter is opposite. Organic carbon mineralization rates of soil with litters rapidly reached maximum in the early days of incubation, and the order is soil with Cynodon dactylon litter (CK + BMD) (23.88 +/- 0.62) mg x d(-1), soil with Pinus massoniana litter (CK+ PML) (17.93 +/- 0.99) mg x d(-1), soil with Quercus acutissima litter (CK+ QAC) (15.39 +/- 0.16) mg x d(-1) and soil with Cyclobalanopsis glauca litter (CK + CGO) (7.26 +/- 0.34) mg x d(-1), and with significant difference between each other (p < 0.05). This order has not significant correlation to litter initial chemical elements. The amount of organic carbon mineralized accumulation within three months incubation is (CK + BMD) (338.21 +/- 6.99) mg, (CK + QAC) (323.48 +/- 13.68) mg, (CK + PML) (278.34 +/- 13.91) mg and (CK + CGO) (245.21 +/- 4.58) mg. 198.17-297.18 mg CO2-C are released during litter incubation, which occupies 20.29%-31.70% of the total litter organic carbon amounts. Power curve model can describe the trends of organic carbon mineralization rate and mineralized accumulation amount,which has a good correlation with their change.

  1. Complexity of carbon market from multi-scale entropy analysis

    NASA Astrophysics Data System (ADS)

    Fan, Xinghua; Li, Shasha; Tian, Lixin

    2016-06-01

    Complexity of carbon market is the consequence of economic dynamics and extreme social political events in global carbon markets. The multi-scale entropy can measure the long-term structures in the daily price return time series. By using multi-scale entropy analysis, we explore the complexity of carbon market and mean reversion trend of daily price return. The logarithmic difference of data Dec16 from August 6, 2010 to May 22, 2015 is selected as the sample. The entropy is higher in small time scale, while lower in large. The dependence of the entropy on the time scale reveals the mean reversion of carbon prices return in the long run. A relatively great fluctuation over some short time period indicates that the complexity of carbon market evolves consistently with economic development track and the events of international climate conferences.

  2. Submicron-Scale Heterogeneities in Nickel Sorption of Various Cell-Mineral Aggregates Formed by Fe(II)-Oxidizing Bacteria.

    PubMed

    Schmid, Gregor; Zeitvogel, Fabian; Hao, Likai; Ingino, Pablo; Adaktylou, Irini; Eickhoff, Merle; Obst, Martin

    2016-01-01

    Fe(II)-oxidizing bacteria form biogenic cell-mineral aggregates (CMAs) composed of microbial cells, extracellular organic compounds, and ferric iron minerals. CMAs are capable of immobilizing large quantities of heavy metals, such as nickel, via sorption processes. CMAs play an important role for the fate of heavy metals in the environment, particularly in systems characterized by elevated concentrations of dissolved metals, such as mine drainage or contaminated sediments. We applied scanning transmission (soft) X-ray microscopy (STXM) spectrotomography for detailed 3D chemical mapping of nickel sorbed to CMAs on the submicron scale. We analyzed different CMAs produced by phototrophic or nitrate-reducing microbial Fe(II) oxidation and, in addition, a twisted stalk structure obtained from an environmental biofilm. Nickel showed a heterogeneous distribution and was found to be preferentially sorbed to biogenically precipitated iron minerals such as Fe(III)-(oxyhydr)oxides and, to a minor extent, associated with organic compounds. Some distinct nickel accumulations were identified on the surfaces of CMAs. Additional information obtained from scatter plots and angular distance maps, showing variations in the nickel-iron and nickel-organic carbon ratios, also revealed a general correlation between nickel and iron. Although a high correlation between nickel and iron was observed in 2D maps, 3D maps revealed this to be partly due to projection artifacts. In summary, by combining different approaches for data analysis, we unambiguously showed the heterogeneous sorption behavior of nickel to CMAs.

  3. Mineral-organic-microbe interactions: Environmental impacts from molecular to macroscopic scales

    NASA Astrophysics Data System (ADS)

    Vaughan, David J.; Lloyd, Jonathan R.

    2011-02-01

    The role of microbes in geological processes is discussed with particular reference to the geochemical cycle involving iron. Microbial oxidation of Fe(II) minerals can occur via at least three mechanisms, the most important involving acidophilic prokaryotes which promote oxidation of iron sulphides. Accelerated breakdown of arsenopyrite is a good example, where multi-step electrochemical reactions are facilitated by the presence of organisms such as Leptospirillum ferrooxidans. Other organisms actively promote the reduction of Fe(III) to more soluble Fe(II). Reduction rates are highly variable, depending on mineral substrate, with oxyhydroxides being most reactive. Proper understanding of such redox processes requires knowledge of interactions at the molecular scale. Advances are being made through genetic studies of relevant organisms, and of mineral surfaces as exemplified by our experimental and computational studies of iron oxides such as magnetite, the reaction of which with simple organic molecules shows diverse behaviour. Mineral-organic interactions precede formation of bacterial biofilms, which can create local geochemical environments causing mineral precipitation. Biofilms and precipitate phases can have a major influence on fluid flow through fractures or porous media as we demonstrate using experiments from micro- to macro-scales.

  4. AMBIENT CARBONATION of MINING RESIDUES: Understanding the Mechanisms and Optimization of Direct Carbon Dioxide Mineral Sequestration

    NASA Astrophysics Data System (ADS)

    Assima, G. P.; Larachi, F.; Molson, J. W.; Beaudoin, G.

    2013-12-01

    The huge amounts (GTs) of ultramafic mining residues (UMRs) produced by mining activities around the world and accumulated in multi-square-kilometer stockpiles are stimulating a vivid interest regarding their possible use as a stable and permanent sink for CO2. Virtually costless and often found crushed and / or ground, UMRs are being considered as ideal candidates for atmospheric CO2 mitigation. The present work, therefore, explores the potential of several UMRs available in Quebec (Thetford Mines, Asbestos, Nunavik, Amos, Otish Mountains), for carbonation under ambient conditions, as a cost-effective alternative to remove low-concentration CO2 from the atmosphere and alleviate global warming. Several experimental reactors have been built to specifically simulate various climatic changes at the laboratory scale. The impact of various environmental conditions to which the residues are subjected to in their storage location, including temperature variations, precipitation, flooding, drought, changing water saturation, oxygen gradient and CO2 diffusion have been thoroughly studied. Dry and heavy-rain periods are unsuitable for efficient CO2 sequestration. Low liquid saturation within UMRs pores favors carbonation by combining fast percolation of gaseous CO2, rapid dissemination of CO2 dissolved species and creation of highly reactive sites throughout the mining residue pile. Partly saturated samples were also found to exhibit lower gaseous CO2 breakthrough times across the mining residues. Warm periods significantly accelerate the rate of CO2 uptake as compared to cold periods, which, in contrast are characterized by heat generation levels that could possibly be exploited by low temperature geothermal systems. A temperature rise from 10 to 40 °C was accompanied by a ten-fold increase in initial reaction rate. The carbonation reaction caused a rise in UMRs temperature up to 4.9°C during experiments at a 10°C. The presence of oxygen in the reaction medium induces

  5. Importance of Carbon Contamination in High-Resolution (FEG) EPMA of Silicate Minerals.

    PubMed

    Buse, Ben; Kearns, Stuart

    2015-06-01

    The effect of carbon contamination on the analysis of carbon-coated silicate minerals at 5 kV for X-ray energies 0.7-4 keV is examined. For individual spot analyses, carbon is found to deposit adjacent to the beam spot forming ring-shaped deposits with no impact on the analysis. Carbon contamination becomes important for closely spaced analyses such as multipoint transects, where each subsequent analysis overlaps the carbon ring of the previous analysis. X-ray intensity loss due to contamination is most severe for low-overvoltage elements such as Ca K consistent with carbon deposition effectively reducing beam energy. Rates of contamination are calculated and the use of a liquid nitrogen cold trap is shown to greatly reduce the amount of carbon deposited. A complimentary empirical correction is developed to correct for X-ray intensity loss from measured carbon, assuming the carbon is a film, and is compared with corrections derived from thin film calculations. PENELOPE electron probe microanalysis (PENEPMA) calculations confirm that asymmetry of the carbon deposition can be ignored for X-ray energies where intensity loss is predominantly through energy loss of beam electrons. Using a cold trap and/or an empirical correction high spatial resolution analysis (ca. 400 nm between points) is achievable with analytical errors of ca. 1-3%.

  6. Carbonate Mineral Formation on Mars: Clues from Stable Isotope Variation Seen in Cryogenic Laboratory Studies of Carbonate Salts

    NASA Technical Reports Server (NTRS)

    Socki, Richard; Niles, Paul B.; Sun, Tao; Fu, Qi; Romanek, Christopher S.; Gibson, Everett K.

    2013-01-01

    The geologic history of water on the planet Mars is intimately connected to the formation of carbonate minerals through atmospheric CO2 and its control of the climate history of Mars. Carbonate mineral formation under modern martian atmospheric conditions could be a critical factor in controlling the martian climate in a means similar to the rock weathering cycle on Earth. The combination of evidence for liquid water on the martian surface and cold surface conditions suggest fluid freezing could be very common on the surface of Mars. Cryogenic calcite forms readily when a rise in pH occurs as a result of carbon dioxide degassing quickly from freezing Ca-bicarbonate-rich water solutions. This is a process that has been observed in some terrestrial settings such as arctic permafrost cave deposits, lakebeds of the Dry Valleys of Antarctica, and in aufeis (river icings) from rivers of N.E. Alaska. We report here the results of a series of laboratory experiments that were conducted to simulate potential cryogenic carbonate formation on the planet Mars. These results indicate that carbonates grown under martian conditions (controlled atmospheric pressure and temperature) show enrichments from starting bicarbonate fluids in both carbon and oxygen isotopes beyond equilibrium values with average delta13C(DIC-CARB) values of 20.5%0 which exceed the expected equilibrium fractionation factor of [10(sup 3) ln alpha = 13%0] at 0 degC. Oxygen isotopes showed a smaller enrichment with delta18O(H2O-CARB) values of 35.5%0, slightly exceeding the equilibrium fractionation factor of [10(sup 3) ln alpha = 34%0 ] at 0degC. Large kinetic carbon isotope effects during carbonate precipitation could substantially affect the carbon isotope evolution of CO2 on Mars allowing for more efficient removal of 13C from the Noachian atmosphere enriched by atmospheric loss. This mechanism would be consistent with the observations of large carbon isotope variations in martian materials despite the

  7. Carbonate Mineral Formation on Mars: Clues from Stable Isotope Variations Seen in Cryogenic Laboratory Studies of Carbonate Salts

    NASA Astrophysics Data System (ADS)

    Socki, R.; Niles, P. B.; Sun, T.; Fu, Q.; Romanek, C. S.; Gibson, E. K.

    2013-12-01

    The geologic history of water on the planet Mars is intimately connected to the formation of carbonate minerals through atmospheric CO2 and its control of the climate history of Mars. Carbonate mineral formation under modern martian atmospheric conditions could be a critical factor in controlling the martian climate in a means similar to the rock weathering cycle on Earth. The combination of evidence for liquid water on the martian surface and cold surface conditions suggest fluid freezing could be very common on the surface of Mars. Cryogenic calcite forms readily when a rise in pH occurs as a result of carbon dioxide degassing quickly from freezing Ca-bicarbonate-rich water solutions. This is a process that has been observed in some terrestrial settings such as arctic permafrost cave deposits, lakebeds of the Dry Valleys of Antarctica, and in aufeis (river icings) from rivers of N.E. Alaska. We report here the results of a series of laboratory experiments that were conducted to simulate potential cryogenic carbonate formation on the planet Mars. These results indicate that carbonates grown under martian conditions (controlled atmospheric pressure and temperature) show enrichments from starting bicarbonate fluids in both carbon and oxygen isotopes beyond equilibrium values with average Δ13C(DIC-CARB) values of ~20.5‰ which exceed the expected equilibrium fractionation factor of [103 ln α = ~13‰] at 0°C. Oxygen isotopes showed a smaller enrichment with Δ18O(H2O-CARB) values of ~35.5‰, slightly exceeding the equilibrium fractionation factor of [103 ln α = ~34‰] at 0°C. Large kinetic carbon isotope effects during carbonate precipitation could substantially affect the carbon isotope evolution of CO2 on Mars allowing for more efficient removal of 13C from the Noachian atmosphere enriched by atmospheric loss. This mechanism would be consistent with the observations of large carbon isotope variations in martian materials despite the relative paucity of

  8. Prevalence and Contribution of Anaerobic Microsites to Carbon Mineralization in Upland Soils

    NASA Astrophysics Data System (ADS)

    Fendorf, S. E.; Keiluweit, M.; Gee, K. E.; Kleber, M.; Wanzek, T.; Nico, P. S.

    2015-12-01

    Soil organic matter (SOM) storage, or residence time, is dominantly controlled by the mineralization (oxidation) rate, which is affected by climatic factors (particularly temperature and rainfall) influencing microbial metabolic rates as well as SOM chemistry, mineral-organic associations, and physical protection. Variation in anaerobic respiratory pathways can further, and dramatically, impact carbon oxidation rates. Within the aggregated structure of soils, steep chemical gradients arise from the supply of oxygen and nutrients along macropores that are rapidly consumed (relative to supply) within the micropore domains of aggregate interiors. As a consequence of demand exceeding oxygen supply within soil aggregates and peds, an appreciable fraction of the soil volume may persist in an anaerobic state within upland, agriculturally productive system. Factors limiting oxygen diffusion and availability such as soil texture, soil moisture content, organic matter input, and aggregate size (soil structure) provide central controls on microbial carbon mineralization rates. Here, we combine laboratory studies with manipulations of field samples and in-field measurements to illustrate how soil structure and carbon availability interact to impose anaerobic conditions and associated respiratory constraints on organic matter mineralization rates and thus storage within soils.

  9. Adsorption of bisphenol-A from aqueous solution onto minerals and carbon adsorbents.

    PubMed

    Tsai, Wen-Tien; Lai, Chi-Wei; Su, Ting-Yi

    2006-06-30

    The adsorption behaviors of bisphenol-A, which has been listed as one of endocrine disrupting chemicals, from aqueous solution onto four minerals including andesite, diatomaceous earth, titanium dioxide, and activated bleaching earth, and two activated carbons with coconut-based and coal-based virgins were examined in this work. Based on the adsorption results at the specified conditions, the adsorption capacities of activated carbons are significantly larger than those of mineral adsorbents, implying that the former is effective for removal of the highly hydrophobic adsorbate from the aqueous solution because of its high surface area and low surface polarity. The adsorption capacities of bisphenol-A onto these mineral adsorbents with different pore properties are almost similar in magnitude mainly due to the weakly electrostatic interaction between the mineral surface with negative charge and the target adsorbate with hydrophobic nature. Further, a simplified kinetic model, pseudo-second-order, was tested to investigate the adsorption behaviors of bisphenol-A onto the two common activated carbons at different solution conditions. It was found that the adsorption process could be well described with the pseudo-second-order model. The kinetic parameters of the model obtained in the present work are in line with the pore properties of the two adsorbents.

  10. Adsorption of bisphenol-A from aqueous solution onto minerals and carbon adsorbents.

    PubMed

    Tsai, Wen-Tien; Lai, Chi-Wei; Su, Ting-Yi

    2006-06-30

    The adsorption behaviors of bisphenol-A, which has been listed as one of endocrine disrupting chemicals, from aqueous solution onto four minerals including andesite, diatomaceous earth, titanium dioxide, and activated bleaching earth, and two activated carbons with coconut-based and coal-based virgins were examined in this work. Based on the adsorption results at the specified conditions, the adsorption capacities of activated carbons are significantly larger than those of mineral adsorbents, implying that the former is effective for removal of the highly hydrophobic adsorbate from the aqueous solution because of its high surface area and low surface polarity. The adsorption capacities of bisphenol-A onto these mineral adsorbents with different pore properties are almost similar in magnitude mainly due to the weakly electrostatic interaction between the mineral surface with negative charge and the target adsorbate with hydrophobic nature. Further, a simplified kinetic model, pseudo-second-order, was tested to investigate the adsorption behaviors of bisphenol-A onto the two common activated carbons at different solution conditions. It was found that the adsorption process could be well described with the pseudo-second-order model. The kinetic parameters of the model obtained in the present work are in line with the pore properties of the two adsorbents. PMID:16343748

  11. Map scale effects on estimating the number of undiscovered mineral deposits

    USGS Publications Warehouse

    Singer, D.A.; Menzie, W.D.

    2008-01-01

    Estimates of numbers of undiscovered mineral deposits, fundamental to assessing mineral resources, are affected by map scale. Where consistently defined deposits of a particular type are estimated, spatial and frequency distributions of deposits are linked in that some frequency distributions can be generated by processes randomly in space whereas others are generated by processes suggesting clustering in space. Possible spatial distributions of mineral deposits and their related frequency distributions are affected by map scale and associated inclusions of non-permissive or covered geological settings. More generalized map scales are more likely to cause inclusion of geologic settings that are not really permissive for the deposit type, or that include unreported cover over permissive areas, resulting in the appearance of deposit clustering. Thus, overly generalized map scales can cause deposits to appear clustered. We propose a model that captures the effects of map scale and the related inclusion of non-permissive geologic settings on numbers of deposits estimates, the zero-inflated Poisson distribution. Effects of map scale as represented by the zero-inflated Poisson distribution suggest that the appearance of deposit clustering should diminish as mapping becomes more detailed because the number of inflated zeros would decrease with more detailed maps. Based on observed worldwide relationships between map scale and areas permissive for deposit types, mapping at a scale with twice the detail should cut permissive area size of a porphyry copper tract to 29% and a volcanic-hosted massive sulfide tract to 50% of their original sizes. Thus some direct benefits of mapping an area at a more detailed scale are indicated by significant reductions in areas permissive for deposit types, increased deposit density and, as a consequence, reduced uncertainty in the estimate of number of undiscovered deposits. Exploration enterprises benefit from reduced areas requiring

  12. Abiotic CO2 reduction during geologic carbon sequestration facilitated by Fe(II)-bearing minerals

    NASA Astrophysics Data System (ADS)

    Nielsen, L. C.; Maher, K.; Bird, D. K.; Brown, G. E.; Thomas, B.; Johnson, N. C.; Rosenbauer, R. J.

    2012-12-01

    Redox reactions involving subsurface minerals and fluids and can lead to the abiotic generation of hydrocarbons from CO2 under certain conditions. Depleted oil reservoirs and saline aquifers targeted for geologic carbon sequestration (GCS) can contain significant quantities of minerals such as ferrous chlorite, which could facilitate the abiotic reduction of carbon dioxide to n-carboxylic acids, hydrocarbons, and amorphous carbon (C0). If such reactions occur, the injection of supercritical CO2 (scCO2) could significantly alter the oxidation state of the reservoir and cause extensive reorganization of the stable mineral assemblage via dissolution and reprecipitation reactions. Naturally occurring iron oxide minerals such as magnetite are known to catalyze CO2 reduction, resulting in the synthesis of organic compounds. Magnetite is thermodynamically stable in Fe(II) chlorite-bearing mineral assemblages typical of some reservoir formations. Thermodynamic calculations demonstrate that GCS reservoirs buffered by the chlorite-kaolinite-carbonate(siderite/magnesite)-quartz assemblage favor the reduction of CO2 to n-carboxylic acids, hydrocarbons, and C0, although the extent of abiotic CO2 reduction may be kinetically limited. To investigate the rates of abiotic CO2 reduction in the presence of magnetite, we performed batch abiotic CO2 reduction experiments using a Dickson-type rocking hydrothermal apparatus at temperatures (373 K) and pressures (100 bar) within the range of conditions relevant to GCS. Blank experiments containing CO2 and H2 were used to rule out the possibility of catalytic activity of the experimental apparatus. Reaction of brine-suspended magnetite nanoparticles with scCO2 at H2 partial pressures typical of reservoir rocks - up to 100 and 0.1 bars respectively - was used to investigate the kinetics of magnetite-catalyzed abiotic CO2 reduction. Later experiments introducing ferrous chlorite (ripidolite) were carried out to determine the potential for

  13. Capacity of microorganisms to decompose organic carbon affected by an increasing content of reactive mineral phases in a podzolic soil chronosequence

    NASA Astrophysics Data System (ADS)

    Vermeire, Marie-Liesse; Doetterl, Sebastian; Bode, Samuel; Delmelle, Pierre; Van Oost, Kristof; Cornelis, Jean-Thomas

    2014-05-01

    Soil organic matter stabilization has received considerable interest in the last decades due to the importance of the soil organic carbon (SOC) pool in the global C budget. There is increasing evidence that the formation of organo-mineral associations play a major role in the mechanisms of organic carbon stabilization, indicating that the persistence of organic matter in soils relates primarily to soil physico-chemical and biological conditions than to intrinsic recalcitrance. Al and Fe oxy-hydroxides and short-range ordered aluminosilicates are known for their high capacity to sorb organic carbon. However, the impact of the evolution of these reactive mineral phases over short time scale on the distribution of microorganisms and their ability to decompose SOC is still poorly understood. To further study the short-term evolution of organo-mineral associations, we investigated a 500-year podzolic soil chronosequence which is characterized by an increasing amount of secondary reactive mineral phases with pedogenesis and soil age, and thus by increased organo-mineral associations. In order to determine the impact of these secondary mineral phases on the degradation of SOC by microorganisms, an incubation experiment was carried out using soil horizons up to 1m deep from 6 profiles of different ages along the chronosequence. Furthermore, we used amino sugars and phospholipid fatty acids as tracers of dead and living microbial biomass, respectively, in the incubated samples. Our results show that SOC mineralization was significantly lower in the illuvial Bh/Bhs horizons (which contain more reactive mineral phases) compared to the surface E horizons (depleted in reactive mineral phases), although the content in amino sugars is similar in these horizons. In the deeper Bw and BC horizons, as well as in the young profiles (<300 yrs) that have not yet undergone podzolization and related formation of organo-mineral associations, SOC mineralization rates were the highest. These

  14. Infrared and Raman spectroscopic characterization of the carbonate mineral huanghoite - And in comparison with selected rare earth carbonates

    NASA Astrophysics Data System (ADS)

    Frost, Ray L.; López, Andrés; Scholz, Ricardo; Xi, Yunfei; Belotti, Fernanda Maria

    2013-11-01

    Raman spectroscopy complimented with infrared spectroscopy has been used to study the rare earth based mineral huanghoite with possible formula given as BaCe(CO3)2F and compared with the Raman spectra of a series of selected natural halogenated carbonates from different origins including bastnasite, parisite and northupite. The Raman spectrum of huanghoite displays three bands are at 1072, 1084 and 1091 cm-1 attributed to the CO32- symmetric stretching vibration. The observation of three symmetric stretching vibrations is very unusual. The position of CO32- symmetric stretching vibration varies with mineral composition. Infrared spectroscopy of huanghoite show bands at 1319, 1382, 1422 and 1470 cm-1. No Raman bands of huanghoite were observed in these positions. Raman spectra of bastnasite, parisite and northupite show a single band at 1433, 1420 and 1554 cm-1 assigned to the ν3 (CO3)2- antisymmetric stretching mode. The observation of additional Raman bands for the ν3 modes for some halogenated carbonates is significant in that it shows distortion of the carbonate anion in the mineral structure. Four Raman bands for huanghoite are observed at 687, 704, 718 and 730 cm-1and assigned to the (CO3)2- ν2 bending modes. Raman bands are observed for huanghoite at around 627 cm-1 and are assigned to the (CO3)2- ν4 bending modes. Raman bands are observed for the carbonate ν4 in phase bending modes at 722 cm-1 for bastnasite, 736 and 684 cm-1 for parisite, 714 cm-1 for northupite. Raman bands for huanghoite observed at 3259, 3484 and 3589 cm-1 are attributed to water stretching bands. Multiple bands are observed in the OH stretching region for bastnasite and parisite indicating the presence of water and OH units in their mineral structure. Vibrational spectroscopy enables new information on the structure of huanghoite to be assessed.

  15. Integration of CO2 capture and mineral carbonation by using recyclable ammonium salts.

    PubMed

    Wang, Xiaolong; Maroto-Valer, M Mercedes

    2011-09-19

    A new approach to capture and store CO(2) by mineral carbonation using recyclable ammonium salts was studied. This process integrates CO(2) capture with mineral carbonation by employing NH(3), NH(4)HSO(4), and NH(4)HCO(3) in the capture, mineral dissolution, and carbonation steps, respectively. NH(4)HSO(4) and NH(3) can then be regenerated by thermal decomposition of (NH(4))(2)SO(4). The use of NH(4)HCO(3) as the source of CO(2) can avoid desorption and compression of CO(2). The mass ratio of Mg/NH(4)HCO(3)/NH(3) is the key factor controlling carbonation and the optimum ratio of 1:4:2 gives a conversion of Mg ions to hydromagnesite of 95.5%. Thermogravimetric analysis studies indicated that the regeneration efficiency of NH(4)HSO(4) and NH(3) in this process is 95%. The mass balance of the process shows that about 2.63 tonnes of serpentine, 0.12 tonnes of NH(4)HSO(4), 7.48 tonnes of NH(4)HCO(3), and 0.04 tonnes of NH(3) are required to sequester 1 tonne of CO(2) as hydromagnesite. PMID:21732542

  16. Experimental Investigation and Simplistic Geochemical Modeling of CO₂ Mineral Carbonation Using the Mount Tawai Peridotite.

    PubMed

    Rahmani, Omeid; Highfield, James; Junin, Radzuan; Tyrer, Mark; Pour, Amin Beiranvand

    2016-01-01

    In this work, the potential of CO₂ mineral carbonation of brucite (Mg(OH)2) derived from the Mount Tawai peridotite (forsterite based (Mg)₂SiO4) to produce thermodynamically stable magnesium carbonate (MgCO3) was evaluated. The effect of three main factors (reaction temperature, particle size, and water vapor) were investigated in a sequence of experiments consisting of aqueous acid leaching, evaporation to dryness of the slurry mass, and then gas-solid carbonation under pressurized CO2. The maximum amount of Mg converted to MgCO₃ is ~99%, which occurred at temperatures between 150 and 175 °C. It was also found that the reduction of particle size range from >200 to <75 µm enhanced the leaching rate significantly. In addition, the results showed the essential role of water vapor in promoting effective carbonation. By increasing water vapor concentration from 5 to 10 vol %, the mineral carbonation rate increased by 30%. This work has also numerically modeled the process by which CO₂ gas may be sequestered, by reaction with forsterite in the presence of moisture. In both experimental analysis and geochemical modeling, the results showed that the reaction is favored and of high yield; going almost to completion (within about one year) with the bulk of the carbon partitioning into magnesite and that very little remains in solution. PMID:26999082

  17. Experimental Investigation and Simplistic Geochemical Modeling of CO₂ Mineral Carbonation Using the Mount Tawai Peridotite.

    PubMed

    Rahmani, Omeid; Highfield, James; Junin, Radzuan; Tyrer, Mark; Pour, Amin Beiranvand

    2016-03-16

    In this work, the potential of CO₂ mineral carbonation of brucite (Mg(OH)2) derived from the Mount Tawai peridotite (forsterite based (Mg)₂SiO4) to produce thermodynamically stable magnesium carbonate (MgCO3) was evaluated. The effect of three main factors (reaction temperature, particle size, and water vapor) were investigated in a sequence of experiments consisting of aqueous acid leaching, evaporation to dryness of the slurry mass, and then gas-solid carbonation under pressurized CO2. The maximum amount of Mg converted to MgCO₃ is ~99%, which occurred at temperatures between 150 and 175 °C. It was also found that the reduction of particle size range from >200 to <75 µm enhanced the leaching rate significantly. In addition, the results showed the essential role of water vapor in promoting effective carbonation. By increasing water vapor concentration from 5 to 10 vol %, the mineral carbonation rate increased by 30%. This work has also numerically modeled the process by which CO₂ gas may be sequestered, by reaction with forsterite in the presence of moisture. In both experimental analysis and geochemical modeling, the results showed that the reaction is favored and of high yield; going almost to completion (within about one year) with the bulk of the carbon partitioning into magnesite and that very little remains in solution.

  18. Scale-dependent associations of Band-tailed Pigeon counts at mineral sites

    USGS Publications Warehouse

    Overton, Cory T.; Casazza, Michael L.; Coates, Peter S.

    2010-01-01

    The abundance of Band-tailed Pigeons (Patagioenas fasciata monilis) has declined substantially from historic numbers along the Pacific Coast. Identification of patterns and causative factors of this decline are hampered because habitat use data are limited, and temporal and spatial variability patterns associated with population indices are not known. Furthermore, counts are influenced not only by pigeon abundance but also by rate of visitation to mineral sites, which may not be consistent. To address these issues, we conducted mineral site counts during 2001 and 2002 at 20 locations from 4 regions in the Pacific Northwest, including central Oregon and western Washington, USA, and British Columbia, Canada. We developed inference models that consisted of environmental factors and spatial characteristics at multiple spatial scales. Based on information theory, we compared models within a final set that included variables measured at 3 spatial scales (0.03 ha, 3.14 ha, and 7850 ha). Pigeon counts increased from central Oregon through northern Oregon and decreased into British Columbia. After accounting for this spatial pattern, we found that pigeon counts increased 12% ± 2.7 with a 10% increase in the amount of deciduous forested area within 100 m from a mineral site. Also, distance from the mineral site of interest to the nearest known mineral site was positively related to pigeon counts. These findings provide direction for future research focusing on understanding the relationships between indices of relative abundance and complete counts (censuses) of pigeon populations by identifying habitat characteristics that might influence visitation rates. Furthermore, our results suggest that spatial arrangement of mineral sites influences Band-tailed Pigeon counts and the populations which those counts represent.

  19. Scale-up of Carbon/Carbon Bipolar Plates

    SciTech Connect

    David P. Haack

    2009-04-08

    This project was focused upon developing a unique material technology for use in PEM fuel cell bipolar plates. The carbon/carbon composite material developed in this program is uniquely suited for use in fuel cell systems, as it is lightweight, highly conductive and corrosion resistant. The project further focused upon developing the manufacturing methodology to cost-effectively produce this material for use in commercial fuel cell systems. United Technology Fuel Cells Corp., a leading fuel cell developer was a subcontractor to the project was interested in the performance and low-cost potential of the material. The accomplishments of the program included the development and testing of a low-cost, fully molded, net-shape carbon-carbon bipolar plate. The process to cost-effectively manufacture these carbon-carbon bipolar plates was focused on extensively in this program. Key areas for cost-reduction that received attention in this program was net-shape molding of the detailed flow structures according to end-user design. Correlations between feature detail and process parameters were formed so that mold tooling could be accurately designed to meet a variety of flow field dimensions. A cost model was developed that predicted the cost of manufacture for the product in near-term volumes and long-term volumes (10+ million units per year). Because the roduct uses lowcost raw materials in quantities that are less than competitive tech, it was found that the cost of the product in high volume can be less than with other plate echnologies, and can meet the DOE goal of $4/kW for transportation applications. The excellent performance of the all-carbon plate in net shape was verified in fuel cell testing. Performance equivalent to much higher cost, fully machined graphite plates was found.

  20. Carbon Mineralization Pathways and Early Diagenesis in Lake Erie Sediments

    NASA Astrophysics Data System (ADS)

    O Neill, A. H.; Crowe, S. A.; Song, Z.; Mucci, A.; Sundby, B.; Fryer, B. J.; Fowle, D. A.

    2004-12-01

    to render solid phase Fe (III) bioavailable. Mn2+ voltammetric peaks were shifted to potentials more negative than the -1.53 to -1.55 mV commonly observed in marine pore waters. This shift is consistent with previous studies in freshwaters and has been ascribed to Mn2+ complexation by organic ligands (e.g. Luther et al, 2003). However, this shift may be due to analytical artifacts associated with using a solid state Ag/AgCl reference electrode in low ionic strength solutions. Measurable sulphide in the first 5 cm below the sediment-water interface is sporadic which suggests that sulphate reduction occurs in micro-environments locally enriched in organic carbon. Preliminary cultivation-independent, microbiological analyses have revealed 16s rDNA clones that are closely related to known species capable of enzymatic reduction of Fe(III) and the dechlorination of organic compounds (e.g. Anaeromyxobacter dehalogenans). These organisms were vertically dispersed within several different core sections suggestive of an intriguing tie between diagenetic reactions and anthropogenic organic compound degradation in these sediments. Coupling high-resolution voltammetry and spatially resolved genomic tools to investigate the controls on sediment pore water chemistry holds a promising future for elucidating the controls on early diagenesis in freshwater ecosystems.

  1. Impact of activated carbon, biochar and compost on the desorption and mineralization of phenanthrene in soil.

    PubMed

    Marchal, Geoffrey; Smith, Kilian E C; Rein, Arno; Winding, Anne; Wollensen de Jonge, Lis; Trapp, Stefan; Karlson, Ulrich G

    2013-10-01

    Sorption of PAHs to carbonaceous soil amendments reduces their dissolved concentrations, limiting toxicity but also potentially biodegradation. Therefore, the maximum abiotic desorption of freshly sorbed phenanthrene (≤5 mg kg(-1)) was measured in three soils amended with activated carbon (AC), biochar or compost. Total amounts of phenanthrene desorbed were similar between the different soils, but the amendment type had a large influence. Complete desorption was observed in the unamended and compost amended soils, but this reduced for biochar (41% desorbed) and AC (8% desorbed). Cumulative amounts mineralized were 28% for the unamended control, 19% for compost, 13% for biochar and 4% for AC. Therefore, the effects of the amendments in soil in reducing desorption were also reflected in the extents of mineralization. Modeling was used to analyze key processes, indicating that for the AC and charcoal treatments bacterial activity did not limit mineralization, but rather desorption into the dissolved phase.

  2. Laboratory-scale column studies to evaluate ureolytically driven CaCO3 mineralization

    NASA Astrophysics Data System (ADS)

    Lauchnor, E.; Phillips, A. J.; Cunningham, A. B.; Gerlach, R.

    2012-12-01

    Calcium carbonate mineralization as a result of the microbial process of ureolysis is being studied for multiple applications in the subsurface. One such potential application is the prevention of near well-bore CO2 leakage by microbially induced carbonate precipitation in small fractures and leakage pathways around wells in CO2 injection sites. The microbially catalyzed hydrolysis of urea increases alkalinity and pH, thus promoting CaCO3 precipitation in the presence of dissolved calcium. While the enzyme urease is widespread among microorganisms, we are studying the kinetics of this process in porous media using the model organism Sporosarcina pasteurii in two foot long, sand-filled columns. The columns contain five sampling ports for spatio-temporal observation of ureolysis and calcium precipitation kinetics. We have evaluated the rates of these reactions under different conditions to optimize the timing of fluid injection and evaluate the effect of different media components on the mineralization process. Additionally, the columns have been operated using an optimized injection strategy of fluids to minimize mineral plugging in the column inlet region. Thus far, these experiments have shown that an economical source of urea (i.e. fertilizer) can be used for this process. To quantify reduction of porosity and plugging in the column, computed x-ray microtomography was performed on the column after mineralization and on an untreated sand-packed column. The reduction in porosity from 48% in clean sand to about 30% in the inlet region and 24% in the rest of the column after mineralization, as determined by CT image analysis, agreed with calculations of the calcite volume occupying the column pore space, determined from destructive measurements of the precipitates. Tracer studies demonstrated reduction in effective porosity from 55% before the experiment to 30% after biomineralization. The goal of these experiments is to better understand the factors involved in

  3. Calcium carbonate mineralization mediated by in vitro cultured mantle cells from Pinctada fucata.

    PubMed

    Kong, Wei; Li, Shiguo; Xiang, Liang; Xie, Liping; Zhang, Rongqing

    2015-08-01

    Formation of the molluscan shell is believed to be an extracellular event mediated by matrix proteins. We report calcium carbonate mineralization mediated by Pinctada fucata mantle cells. Crystals only appeared when mantle cells were present in the crystallization solution. These crystals were piled up in highly ordered units and showed the typical characteristics of biomineralization products. A thin organic framework was observed after dissolving the crystals in EDTA. Some crystals had etched surfaces with a much smoother appearance than other parts. Mantle cells were observed to be attached to some of these smooth surfaces. These results suggest that mantle cells may be directly involved in the nucleation and remodeling process of calcium carbonate mineralization. Our result demonstrate the practicability of studying the mantle cell mechanism of biomineralization and contribute to the overall understanding of the shell formation process.

  4. Interactions of 14C-labeled multi-walled carbon nanotubes with soil minerals in water.

    PubMed

    Zhang, Liwen; Petersen, Elijah J; Zhang, Wen; Chen, Yongsheng; Cabrera, Miguel; Huang, Qingguo

    2012-07-01

    Carbon nanotubes are often modified to be stable in the aqueous phase by adding extensive hydrophilic surface functional groups. The stability of such CNTs in water with soil or sediment is one critical factor controlling their environmental fate. We conducted a series of experiments to quantitatively assess the association between water dispersed multi-walled carbon nanotubes (MWCNTs) and three soil minerals (kaolinite, smectite, or shale) in aqueous solution under different sodium concentrations. (14)C-labeling was used in these experiments to unambiguously quantify MWCNTs. The results showed that increasing ionic strength strongly promoted the removal of MWCNTs from aqueous phase. The removal tendency is inversely correlated with the soil minerals' surface potential and directly correlated with their hydrophobicity. This removal can be interpreted by the extended Derjaguin-Landau-Verwey-Overbeek (EDLVO) theory especially for kaolinite and smectite. Shale, which contains large and insoluble organic materials, sorbed MWCNTs the most strongly.

  5. The effect of SO2 on mineral carbonation in batch tests

    SciTech Connect

    Summers, Cathy A.; Dahlin, David C.; Ochs, Thomas L.

    2004-01-01

    CO2 sequestration is a key element of future emission-free fossil-fueled power plants. Other constituents of flue gas must also be captured and rendered innocuous. Contemporary power plants remove SOx from exit gases, but next-generation plants may simultaneously treat CO2, SOx, and other pollutants. Pioneering tests at the U.S. Department of Energy's Albany Research Center investigated the combined treatment of CO2 and SO2 in a mineral-carbonation process. SO2 was removed from the gas stream, and as a small fraction of the total volume of mineralizing gas, it did not inhibit the carbonation reaction. The results indicate that this approach to CO2 sequestration could be used to treat multiple pollutants.

  6. Crystal chemical correlations between the mid and near-infrared in carbonate minerals

    NASA Astrophysics Data System (ADS)

    Hopkinson, Laurence; Rutt, Ken J.

    2016-06-01

    Near-infrared (NIR) spectra of carbonates have proved important in many disciplines including planetary exploration. Classically bands in the 4000-6000 cm- 1 (2.5-1.67 μm) region are assigned to [CO32-] internal mode combinations and overtones. However band assignments remain equivocal. This study examines three prominent bands ((ca 4505 cm- 1 (2.219 μm), 4900 cm- 1 (2.041 μm) and 5145 cm- 1 (1.944 μm)) from powdered calcite and aragonite group minerals. Results indicate that the bands originate from anharmonic coupling of degenerate internal mode(s) with external (lattice) modes. On this basis it is suggested that NIR data may provide an untapped source of detailed information on lattice mode frequencies and information on the type(s) of the environmental cation(s) in carbonate minerals.

  7. Prediction of soil organic carbon concentration and soil bulk density of mineral soils for soil organic carbon stock estimation

    NASA Astrophysics Data System (ADS)

    Putku, Elsa; Astover, Alar; Ritz, Christian

    2016-04-01

    Soil monitoring networks provide a powerful base for estimating and predicting nation's soil status in many aspects. The datasets of soil monitoring are often hierarchically structured demanding sophisticated data analyzing methods. The National Soil Monitoring of Estonia was based on a hierarchical data sampling scheme as each of the monitoring site was divided into four transects with 10 sampling points on each transect. We hypothesized that the hierarchical structure in Estonian Soil Monitoring network data requires a multi-level mixed model approach to achieve good prediction accuracy of soil properties. We used this database to predict soil bulk density and soil organic carbon concentration of mineral soils in arable land using different statistical methods: median approach, linear regression and mixed model; additionally, random forests for SOC concentration. We compared the prediction results and selected the model with the best prediction accuracy to estimate soil organic carbon stock. The mixed model approach achieved the best prediction accuracy in both soil organic carbon (RMSE 0.22%) and bulk density (RMSE 0.09 g cm-3) prediction. Other considered methods under- or overestimated higher and lower values of soil parameters. Thus, using these predictions we calculated the soil organic carbon stock of mineral arable soils and applied the model to a specific case of Tartu County in Estonia. Average estimated SOC stock of Tartu County is 54.8 t C ha-1 and total topsoil SOC stock 1.8 Tg in humus horizon.

  8. Calibrating the ChemCam laser-induced breakdown spectroscopy instrument for carbonate minerals on Mars

    SciTech Connect

    Lanza, Nina L.; Wiens, Roger C.; Clegg, Samuel M.; Ollila, Ann M.; Humphries, Seth D.; Newsom, Horton E.; Barefield, James E.

    2010-05-01

    The ChemCam instrument suite onboard the NASA Mars Science Laboratory rover includes the first laser-induced breakdown spectroscopy (LIBS) instrument for extraterrestrial applications. Here we examine carbonate minerals in a simulated martian environment to better understand the LIBS signature of these materials on Mars. Both chemical composition and rock type are determined using multivariate analysis techniques. Composition is confirmed using scanning electron microscopy. Our results show that ChemCam can recognize and differentiate between different types of carbonate materials on Mars.

  9. Calibrating the ChemCam LIBS for carbonate minerals on Mars

    SciTech Connect

    Wiens, Roger C; Clegg, Samuel M; Ollila, Ann M; Barefield, James E; Lanza, Nina; Newsom, Horton E

    2009-01-01

    The ChemCam instrument suite on board the NASA Mars Science Laboratory (MSL) rover includes the first LIBS instrument for extraterrestrial applications. Here we examine carbonate minerals in a simulated martian environment using the LIDS technique in order to better understand the in situ signature of these materials on Mars. Both chemical composition and rock type are determined using multivariate analysis (MVA) techniques. Composition is confirmed using scanning electron microscopy (SEM) techniques. Our initial results suggest that ChemCam can recognize and differentiate between carbonate materials on Mars.

  10. Calibrating the ChemCam LIBS for Carbonate Minerals on Mars

    DOE R&D Accomplishments Database

    Wiens, Roger C.; Clegg, Samuel M.; Ollila, Ann M.; Barefield, James E.; Lanza, Nina; Newsom, Horton E.

    2009-01-01

    The ChemCam instrument suite on board the NASA Mars Science Laboratory (MSL) rover includes the first LIBS instrument for extraterrestrial applications. Here we examine carbonate minerals in a simulated martian environment using the LIDS technique in order to better understand the in situ signature of these materials on Mars. Both chemical composition and rock type are determined using multivariate analysis (MVA) techniques. Composition is confirmed using scanning electron microscopy (SEM) techniques. Our initial results suggest that ChemCam can recognize and differentiate between carbonate materials on Mars.

  11. Mineral resources of the Prospect Mountain Wilderness Study Area, Carbon County, Wyoming

    SciTech Connect

    du Bray, E.A.; Bankey, V.; Hill, R.H.; Ryan, G.S.

    1989-01-01

    The Prospect Mountain Wilderness Study Area is about 20 mi east-southeast of Encampment in Carbon County, Wyoming. This study area is underlain by middle Proterozoic gabbro, granite, and hornblende gneiss, which is locally cut by pegmatite dikes. There are no identified resources and no potential for undiscovered energy resources in this study area. Resource potential for all undiscovered metallic commodities and for industrial mineral is low.

  12. Assessment of mercury exposure among small-scale gold miners using mercury stable isotopes

    SciTech Connect

    Sherman, Laura S.; Blum, Joel D.; Basu, Niladri; Rajaee, Mozhgon; Evers, David C.; Buck, David G.; Petrlik, Jindrich; DiGangi, Joseph

    2015-02-15

    Total mercury (Hg) concentrations in hair and urine are often used as biomarkers of exposure to fish-derived methylmercury (MeHg) and gaseous elemental Hg, respectively. We used Hg stable isotopes to assess the validity of these biomarkers among small-scale gold mining populations in Ghana and Indonesia. Urine from Ghanaian miners displayed similar Δ{sup 199}Hg values to Hg derived from ore deposits (mean urine Δ{sup 199}Hg=0.01‰, n=6). This suggests that urine total Hg concentrations accurately reflect exposure to inorganic Hg among this population. Hair samples from Ghanaian miners displayed low positive Δ{sup 199}Hg values (0.23–0.55‰, n=6) and low percentages of total Hg as MeHg (7.6–29%, n=7). These data suggest that the majority of the Hg in these miners' hair samples is exogenously adsorbed inorganic Hg and not fish-derived MeHg. Hair samples from Indonesian gold miners who eat fish daily displayed a wider range of positive Δ{sup 199}Hg values (0.21–1.32‰, n=5) and percentages of total Hg as MeHg (32–72%, n=4). This suggests that total Hg in the hair samples from Indonesian gold miners is likely a mixture of ingested fish MeHg and exogenously adsorbed inorganic Hg. Based on data from both populations, we suggest that total Hg concentrations in hair samples from small-scale gold miners likely overestimate exposure to MeHg from fish consumption. - Highlights: • Mercury isotopes were measured in hair and urine from small-scale gold miners. • Mercury isotopes indicate that Hg in urine comes from mining activity. • Mercury isotopes suggest Hg in hair is a mixture of fish MeHg and inorganic Hg. • A large percentage of Hg in miner’s hair is released during amalgam burning and adsorbed.

  13. Short-term variability of mineral dust, metals and carbon emission from road dust resuspension

    NASA Astrophysics Data System (ADS)

    Amato, Fulvio; Schaap, Martijn; Denier van der Gon, Hugo A. C.; Pandolfi, Marco; Alastuey, Andrés; Keuken, Menno; Querol, Xavier

    2013-08-01

    Particulate matter (PM) pollution in cities has severe impact on morbidity and mortality of their population. In these cities, road dust resuspension contributes largely to PM and airborne heavy metals concentrations. However, the short-term variation of emission through resuspension is not well described in the air quality models, hampering a reliable description of air pollution and related health effects. In this study we experimentally show that the emission strength of resuspension varies widely among road dust components/sources. Our results offer the first experimental evidence of different emission rates for mineral dust, heavy metals and carbon fractions due to traffic-induced resuspension. Also, the same component (or source) recovers differently in a road in Barcelona (Spain) and a road in Utrecht (The Netherlands). This finding has important implications on atmospheric pollution modelling, mostly for mineral dust, heavy metals and carbon species. After rain events, recoveries were generally faster in Barcelona rather than in Utrecht. The largest difference was found for the mineral dust (Al, Si, Ca). Tyre wear particles (organic carbon and zinc) recovered faster than other road dust particles in both cities. The source apportionment of road dust mass provides useful information for air quality management.

  14. Control of mineral scale deposition in cooling systems using secondary-treated municipal wastewater.

    PubMed

    Li, Heng; Hsieh, Ming-Kai; Chien, Shih-Hsiang; Monnell, Jason D; Dzombak, David A; Vidic, Radisav D

    2011-01-01

    Secondary-treated municipal wastewater (MWW) is a promising alternative to freshwater as power plant cooling system makeup water, especially in arid regions. A prominent challenge for the successful use of MWW for cooling is potentially severe mineral deposition (scaling) on pipe surfaces. In this study, theoretical, laboratory, and field work was conducted to evaluate the mineral deposition potential of MWW and its deposition control strategies under conditions relevant to power plant cooling systems. Polymaleic acid (PMA) was found to effectively reduce scale formation when the makeup water was concentrated four times in a recirculating cooling system. It was the most effective deposition inhibitor of those studied when applied at 10 mg/L dosing level in a synthetic MWW. However, the deposition inhibition by PMA was compromised by free chlorine added for biogrowth control. Ammonia present in the wastewater suppressed the reaction of the free chlorine with PMA through the formation of chloramines. Monochloramine, an alternative to free chlorine, was found to be less reactive with PMA than free chlorine. In pilot tests, scaling control was more challenging due to the occurrence of biofouling even with effective control of suspended bacteria. Phosphorous-based corrosion inhibitors are not appropriate due to their significant loss through precipitation reactions with calcium. Chemical equilibrium modeling helped with interpretation of mineral precipitation behavior but must be used with caution for recirculating cooling systems, especially with use of MWW, where kinetic limitations and complex water chemistries often prevail. PMID:20851443

  15. Exploring biotic vs. abiotic controls on syngenetic carbonate and clay mineral precipitation

    NASA Astrophysics Data System (ADS)

    Nascimento, Gabriela S.; McKenzie, Judith A.; Martinez Ruiz, Francisca; Bontognali, Tomaso R. R.; Vasconcelos, Crisogono

    2016-04-01

    A possible syngenetic relationship between carbonate and clay mineral precipitation has been reported for sedimentary rocks deposited in both lacustrine and marine sedimentary environments throughout the geological record. In particular, the mineral dolomite is often found associated with Mg-rich clays, such as stevensite. It is notable that this carbonate/clay association has been recorded in numerous samples taken from modern dolomite precipitating environments; for example, the Coorong lakes, South Australia, coastal sabkhas, Abu Dhabi, UAE and coastal hypersaline lagoons (Lagoa Vermelha and Brejo do Espinho) east of Rio de Janeiro, Brazil. An HRTEM study of samples from these three locations indicates a possible physical/chemical association between the Ca-dolomite and Mg-rich clays, demonstrating a probable co-precipitation. To test this hypothesis, we have conducted a series of biotic and abiotic laboratory experiments. If this syngenesis actually occurs in nature, what, if any, are the biogeochemical processes controlling these precipitation reactions? Our experiments were designed to determine the extent of the biotic versus abiotic component influencing the mineral precipitation and, in the case of a biotic influence, to understand the mechanism through which microorganisms might mediate the formation of clay minerals. The experiments were carried out in the Geomicrobiology Laboratory of ETH Zürich using cultures of living microbes and artificial organic compounds that simulate functional groups present in natural biofilms formed under both aerobic and anaerobic conditions. In addition, pure inorganic experiments were designed to understand possible physico-chemical conditions for diagenetic processes that could induce dissolution of Mg-carbonates and precipitation of Mg-rich clays. Our results show a remarkable biotic influence during the formation of clay minerals. Specifically, extracellular polymeric substances (EPS), released by microbes in their

  16. Implications of carbon saturation model structures for simulated nitrogen mineralization dynamics

    NASA Astrophysics Data System (ADS)

    White, C. M.; Kemanian, A. R.; Kaye, J. P.

    2014-12-01

    Carbon (C) saturation theory suggests that soils have a limited capacity to stabilize organic C and that this capacity may be regulated by intrinsic soil properties such as clay concentration and mineralogy. While C saturation theory has advanced our ability to predict soil C stabilization, few biogeochemical ecosystem models have incorporated C saturation mechanisms. In biogeochemical models, C and nitrogen (N) cycling are tightly coupled, with C decomposition and respiration driving N mineralization. Thus, changing model structures from non-saturation to C saturation dynamics can change simulated N dynamics. In this study, we used C saturation models from the literature and of our own design to compare how different methods of modeling C saturation affected simulated N mineralization dynamics. Specifically, we tested (i) how modeling C saturation by regulating either the transfer efficiency (ɛ, g C retained g-1 C respired) or transfer rate (k) of C to stabilized pools affected N mineralization dynamics, (ii) how inclusion of an explicit microbial pool through which C and N must pass affected N mineralization dynamics, and (iii) whether using ɛ to implement C saturation in a model results in soil texture controls on N mineralization that are similar to those currently included in widely used non-saturating C and N models. Models were parameterized so that they rendered the same C balance. We found that when C saturation is modeled using ɛ, the critical C : N ratio for N mineralization from decomposing plant residues (rcr) increases as C saturation of a soil increases. When C saturation is modeled using k, however, rcr is not affected by the C saturation of a soil. Inclusion of an explicit microbial pool in the model structure was necessary to capture short-term N immobilization-mineralization turnover dynamics during decomposition of low N residues. Finally, modeling C saturation by regulating ɛ led to similar soil texture controls on N mineralization as a

  17. Calcium carbonate scale control, effect of material and inhibitors.

    PubMed

    Macadam, J; Parsons, S A

    2004-01-01

    This paper focuses on developing a reproducible method for reducing calcium carbonate scale formation on heated surfaces where scaling can cause serious problems. It is known that calcium carbonate precipitation is sensitive to impurity ions, such as iron and zinc, even at trace concentration levels. In this paper two sets of experiments are reported. The first experiments were undertaken to investigate the effect of zinc, copper and iron dosing on CaCO3 nucleation and precipitation. Results from the experiments showed that the most effective inhibitor of CaCO3 precipitation was zinc and the effect was linked to dose levels and temperature. Copper and iron had little effect on precipitation in the dose range investigated. The second trial was undertaken to translate the precipitation data to scale formation. These tests were undertaken at 70 degrees C. 5 mg x L(-1) zinc dose reduced the scale formation by 35%. The effect of iron on calcium carbonate scaling rate was not significant. The physical nature of the material on which the scale is formed also influences the scaling. The scaling experiment was also used to investigate the effect of different surface material (stainless steel, copper and aluminium) on CaCO3 scale formation. Copper surface scaled the most.

  18. Do Forest Age and Soil Depth Affect Carbon and Nitrogen Adsorption in Mineral Horizons?

    NASA Astrophysics Data System (ADS)

    Spina, P. G.; Lovett, G. M.; Fuss, C. B.; Goodale, C. L.; Lang, A.; Fahey, T.

    2015-12-01

    Mineral soils retain large amounts of organic matter through sorption on the surfaces of mineral soils, the largest pools of carbon (C) and nitrogen (N) in the forests of the northeastern U.S. In addition to determining organic matter storage, adsorption and desorption processes are important controllers of runoff chemistry. We are studying adsorption dynamics of mineral soils collected from a chronosequence of hardwood forest sites in the White Mountains, NH to determine how soils vary in their DOM adsorption capacities as a function of effective C and N saturation. We hypothesize that forest age determines proximity to saturation because young forests may need to mine soil organic matter (SOM) in mineral soils to obtain nitrogen to meet growth demands, while the soils of older forests have had time to reaccumulate SOM, eventually reaching C and N saturation. Consequently, we expect adsorption capacities to first increase with forest age in young forests, as the trees mine C and N from mineral surfaces. They will then decrease with forest age in older forests as mining slows and C and N begin to re-accumulate. Batch experiments were conducted with mineral soil samples and dilutions of forest floor leachate. However, preliminary results from a mature forest site (about 100 years old), which we predicted to be a low point of C and N saturation from decades of mining, contradict expectations. Dissolved organic carbon (DOC) adsorption in its shallow mineral soil layers (0-3 cm below E or A horizons) are lower than younger sites ranging from 20 to about 40 years old. In addition to forest age, soil depths also affect N retention dynamics in forest soils. We hypothesized that deeper mineral soils might have greater adsorption capacities due to the fact that they are exposed to less DOC and DON leaching from organic layers and therefore less saturated. Results from the same mature forest site confirm this. Soils from 3-10 cm depth have more potential to adsorb DOC and

  19. Microbial and Chemical Enhancement of In-Situ Carbon Mineralization in Geological Formation

    SciTech Connect

    Matter, J.; Chandran, K.

    2013-05-31

    Predictions of global energy usage suggest a continued increase in carbon emissions and rising concentrations of CO{sub 2} in the atmosphere unless major changes are made to the way energy is produced and used. Various carbon capture and storage (CCS) technologies are currently being developed, but unfortunately little is known regarding the fundamental characteristics of CO{sub 2}-mineral reactions to allow a viable in-situ carbon mineralization that would provide the most permanent and safe storage of geologically-injected CO{sub 2}. The ultimate goal of this research project was to develop a microbial and chemical enhancement scheme for in-situ carbon mineralization in geologic formations in order to achieve long-term stability of injected CO{sub 2}. Thermodynamic and kinetic studies of CO{sub 2}-mineral-brine systems were systematically performed to develop the in-situ mineral carbonation process that utilizes organic acids produced by a microbial reactor. The major participants in the project are three faculty members and their graduate and undergraduate students at the School of Engineering and Applied Science and at the Lamont-Doherty Earth Observatory at Columbia University: Alissa Park in Earth and Environmental Engineering & Chemical Engineering (PI), Juerg Matter in Earth and Environmental Science (Co-PI), and Kartik Chandran in Earth and Environmental Engineering (Co-PI). Two graduate students, Huangjing Zhao and Edris Taher, were trained as a part of this project as well as a number of graduate students and undergraduate students who participated part-time. Edris Taher received his MS degree in 2012 and Huangjing Zhao will defend his PhD on Jan. 15th, 2014. The interdisciplinary training provided by this project was valuable to those students who are entering into the workforce in the United States. Furthermore, the findings from this study were and will be published in referred journals to disseminate the results. The list of the papers is given at

  20. Persistence of Mineral-Associated Soil Organic Carbon in European Soil Profiles

    NASA Astrophysics Data System (ADS)

    Mayer, A.; Schrumpf, M.; Trumbore, S.

    2014-12-01

    Soil Organic Carbon (SOC) is a heterogeneous mixture of components that are not equally biologically available, including light, plant derived material, dissolved organic carbon, and mineral-associated organic matter (MOM). Radiocarbon ages of bulk SOC average across this heterogeneity. Of particular interest is whether there are small amounts of very old OC (the so-called 'passive' pool) that can mask the fact that much of the OM is much younger. MOM has been shown to be older than the light fraction and DOC, but MOM is also a mixture of old and young material. This study seeks to clarify the quantity of C persisting on millennial time scales at different depths in the soil profile, and what factors allow this fraction to be more persistent than other fractions. We studied the fraction and age of C of the most chemically and physically stable fraction we could isolate from five European soils with differing land use, parent material, and soil type. First we isolated the MOM fraction by density, and then oxidized the MOM fraction with H2O2 to remove the labile C. The oxidation resistant residue was analyzed for C content and radiocarbon signature. The oxidation procedure removed 70-95% of the MOM fraction; the residue had a consistently older radiocarbon signature than the initial MOM, indicating that the C removed was younger than the bulk average. This stable fraction ranged from 100 radiocarbon years Before Present (BP) in the top 5 cm, to 10,000 years BP at the 30-40 cm depth. Non-crystalline iron concentrations were correlated with the absolute amount of SOC protected from oxidation, but not its proportion or age. With the exception of a tilled cropland site, all examined profiles exhibited a nearly linear depletion in radiocarbon signature with depth in both the protected and oxidizable MOM, confirming that the most chemically and physically stable C is oldest at the deepest point in a 50 cm profile. Ongoing work on this study will further elucidate how the

  1. Redistributed water by saprotrophic fungi triggers carbon mineralization in dry soils

    NASA Astrophysics Data System (ADS)

    Guhr, Alexander; Borken, Werner; Matzner, Egbert

    2015-04-01

    Summer droughts are common in temperate forests and especially the upper soil horizons experience soil drought. Drought events can be accompanied by negative effects for forest ecosystems but many plants can reduce drought stress by hydraulic redistribution (HR). Similar processes were recently described for ectomycorrhizal networks but no information is available for mycelia networks of saprotrophic fungi. They strongly contribute to belowground nutrient cycling, C and N mineralization. We hypothesize that redistributed water by saprotrophic fungi triggers mineralization of organic matter in soils under drought conditions. The impact of HR by saprotrophic fungi on mineralization was determined using mesocosms comprising two chambers, separated by a 2 mm air gap to prevent bulk flow of water. After inoculation with fungal cultures and a growth phase, both chambers were desiccated. Subsequently, only chamber I was rewetted while chamber II was treated with 13C labelled plant material. CO2 samples were collected over 7 days after rewetting and analyzed for stable isotope ratio. In addition, enzymatic activity of chitinases and cellobiohydrolases in chamber II was determined after 7 days using the soil zymographie method with fluorogenic 4-Methylumbelliferyl-substrates. A negative control was provided by mesocosms in which hyphal connections between the chambers were severed before rewetting. Intact fungal connections between the chambers led to a strong increase in volumetric water content in chamber II after rewetting of chamber I and the CO2 had a higher enrichment in 13C than in the control mescosms with severed connections. Enrichment started 48 h after rewetting and continued for the rest of the experiment. This resulted in a more than two fold higher total carbon mineralization after 7 days in chamber II of mesocosms with intact hyphal connections. In addition, enzyme activities were also strongly increased compared to controls. In conclusion, mycelia networks

  2. Earthworms facilitate carbon sequestration through unequal amplification of carbon stabilization compared with mineralization

    EPA Science Inventory

    A recent review concluded that earthworm presence increases CO2 emissions by 33% but does not affect soil organic carbon stocks. However, the findings are controversial and raise new questions. Here we hypothesize that neither an increase in CO2 emission nor in stabilized carbon...

  3. Relative control of dissolved organic matter (DOM) composition and concentration for carbon-mineral complexation

    NASA Astrophysics Data System (ADS)

    Pan, W.; Inamdar, S. P.; Sparks, D. L.; Aufdenkampe, A. K.; Yoo, K.

    2012-12-01

    Growing concern about climate change has evoked considerable interest in the soil carbon (C) pool, the second largest C-sink on the earth. C-mineral complexation formed by ligand exchange between DOM and soil is considered as the dominant mechanism for DOM sorption and stabilization in soil. Despite intensive sorption studies, our understanding of how DOM composition influences sorption is still fairly limited. The objectives of the proposed study are: (a) to investigate the relative control of DOM composition and concentration on C-mineral complexation and (b) to determine the DOM composition metrics that are associated with irreversible binding between carbon and mineral surfaces. To address these objectives, we investigated the sorption of DOM isolated and extracted from 12 different watershed sources to goethite (a-FeOOH) with batch sorption and desorption experiments. Fluorescence-EEM and UV-absorbance methods were used to characterize DOM composition through a variety of metrics. DOM composition varied considerably for the 12 DOM solutions. With all DOM solutions adjusted to a DOC concentration of 30mgC/L, humification index (HIX) value ranged from 0.18 to 0.8 and the specific UV absorbance (SUVA) ranged from 1.12 to 3.70. The increase of 2 pH units after sorption indicated ligand exchange was likely the dominant process during sorption. The aromatic and humic-like DOM substances were preferentially sorbed. Preliminary results suggest that carbon mineral complexation (OC/SSA) was influenced by both, the concentration as well as the composition of the DOM. The explanatory power of the regression equations predicting DOM sorption to goethite was increased by the including of DOM composition matrix. The sorption isotherm revealed that DOM composition has a significant influence on the shape of the isotherms.

  4. Carbon Dioxide Mineralization in the Presence of Convective Mixing and the Capillary Transition Zone

    NASA Astrophysics Data System (ADS)

    Elenius, M. T.; Farshidi, S.; Voskov, D.; Tchelepi, H.

    2015-12-01

    Dissolution of carbon dioxide (CO2) is one of the major trapping mechanisms for carbon storage in saline aquifers. Due to a small density increase when CO2 dissolves in brine, convection cells may establish and greatly enhance the rate at which CO2 is dissolved. This important and complex process has been then a topic of large interest in the community over the last decade. We have previously shown that there is an interaction between the Capillary Transition Zone (CTZ) in the CO2 plume, and convective mixing, and that this causes significantly enhanced dissolution rates compared to a scenario that most authors have used with no flow across this interface. The rate of dissolution from the plume may also be affected by mineral reactions. Andres and Cardoso [1] showed that for the mineralization of CO2 due to silicate dissolution followed by precipitation of carbonate and clay, there is a threshold reaction rate above which convection does not appear. However, they do not account for the CTZ or depletion of the silicate. We study the impact of the CTZ on convective mixing, in a system that features mineralization of CO2. The reactivity is enhanced with CO2 concentration and with the amount of silicate (anorthite). Results from linear stability analysis and numerical simulations support each other. The rate of CO2 dissolution can be an order of magnitude enhanced by mineralization, when the CTZ and depletion of the anorthite are accounted for. Limiting reaction rates for convection are established as a function of the characteristics of the CTZ.[1] Andres, J.T.H. and Cardoso, S.S.S. 2011. Onset of convection in a porous medium in the presence of chemical reaction. Physical Review E (83), 046312.

  5. Bulk and stable isotopic compositions of carbonate minerals in Martian meteorite Allan Hills 84001: no proof of high formation temperature.

    PubMed

    Treiman, A H; Romanek, C S

    1998-07-01

    Understanding the origin of carbonate minerals in the Martian meteorite Allan Hills (ALH) 84001 is crucial to evaluating the hypothesis that they contain traces of ancient Martian life. Using arguments based on chemical equilibria among carbonates and fluids, an origin at >650 degrees C (inimical to life) has been proposed. However, the bulk and stable isotopic compositions of the carbonate minerals are open to multiple interpretations and so lend no particular support to a high-temperature origin. Other methods (possibly less direct) will have to be used to determine the formation temperature of the carbonates in ALH84001. PMID:11543073

  6. Bulk and Stable Isotopic Compositions of Carbonate Minerals in Martian Meteorite Allan Hills 84001: No Proof of High Formation Temperature

    NASA Technical Reports Server (NTRS)

    Treiman, Allan H.; Romanek, Christopher S.

    1998-01-01

    Understanding the origin of carbonate minerals in the Martian meteorite Allan Hills (ALH) 84001 is crucial to evaluating the hypothesis that they contain traces of ancient Martian life. Using arguments based on chemical equilibria among carbonates and fluids, an origin at greater than 650 C (inimical to life) has been proposed. However, the bulk and stable isotopic compositions of the carbonate minerals are open to multiple interpretations and so lend no particular support to a high-temperature origin. Other methods (possibly less direct) will have to be used to determine the formation temperature of the carbonates in ALH 84001.

  7. ATOMIC-LEVEL IMAGING OF CO2 DISPOSAL AS A CARBONATE MINERAL: OPTIMIZING REACTION PROCESS DESIGN

    SciTech Connect

    M.J. McKelvy; R. Sharma; A.V.G. Chizmeshya; H. Bearat; R.W. Carpenter; K. Streib

    1999-09-01

    Fossil fuels, especially coal, can support the energy demands of the world for centuries to come, if the environmental problems associated with CO{sub 2} emissions can be overcome. Permanent and safe methods for CO{sub 2} capture and disposal/storage need to be developed. Mineralization of stationary-source CO{sub 2} emissions as carbonates can provide such safe capture and long-term sequestration. Mg(OH){sub 2} carbonation is a leading process candidate, which generates the stable naturally occurring mineral magnesite (MgCO{sub 3}) and water. Key to process cost and viability are the carbonation reaction rate and its degree of completion. This process, which involves simultaneous dehydroxylation and carbonation is very promising, but far from optimized. In order to optimize the dehydroxylation/carbonation process, an atomic-level understanding of the mechanisms involved is needed. Since Mg(OH){sub 2} dehydroxylation is intimately associated with the carbonation process, its mechanisms are also of direct interest in understanding and optimizing the process. In the first project year, our investigations have focused on developing an atomic-level understanding of the dehydroxylation/carbonation reaction mechanisms that govern the overall carbonation reaction process in well crystallized material. In years two and three, we will also explore the roles of crystalline defects and impurities. Environmental-cell, dynamic high-resolution transmission electron microscopy has been used to directly observe the dehydroxylation process at the atomic-level for the first time. These observations were combined with advanced computational modeling studies to better elucidate the atomic-level process. These studies were combined with direct carbonation studies to better elucidate dehydroxylation/carbonation reaction mechanisms. Dehydroxylation follows a lamellar nucleation and growth process involving oxide layer formation. These layers form lamellar oxyhydroxide regions, which can

  8. Injuries among Artisanal and Small-Scale Gold Miners in Ghana

    PubMed Central

    Kyeremateng-Amoah, E.; Clarke, Edith E.

    2015-01-01

    Artisanal and small-scale gold miners are confronted with numerous hazards often resulting in varying degrees of injuries and fatalities. In Ghana, like many developing countries, there is paucity of information on the causes and nature of the accidents that result in the injuries. The study was a retrospective, cross sectional type that examined the records of injuries of artisanal and small-scale gold miners presented to the emergency department of a district hospital in the Eastern Region of Ghana from 2006 to 2013. The causes, types, and outcomes of reported injuries were analyzed for 72 cases. Occurrences of mining accidents reported in selected Ghanaian media during the year 2007–2012 were also analyzed to corroborate the causes of the accidents. Fractures and contusions constituted the most frequently occurring injuries, with collapse of the mine pits and falls being the most frequent cause of accidents reported both by the hospital and media records. This study shows that though varied degrees of injuries occur among the miners, the potential for serious injuries is substantial. Measures to reduce the incidence of injuries and fatalities should include education and training on the use of safe working tools and means of creating a safe working environment. PMID:26404345

  9. Geochemical modeling of the influence of silicate mineral alteration on alkalinity production and carbonate precipitation

    NASA Astrophysics Data System (ADS)

    Herda, Gerhard; Kraemer, Stephan M.; Gier, Susanne; Meister, Patrick

    2016-04-01

    High CO2 partial pressure (pCO2) in deep rock reservoirs causes acidification of the porefluid. Such conditions occur during injection and subsurface storage of CO2 (to prevent the release of greenhouse gas) but also naturally in zones of strong methanogenic microbial activity in organic matter-rich ocean margin sediments. The acidic fluids are corrosive to carbonates and bear the risk of leakage of CO2 gas to the surface. Porefluid acidification may be moderated by processes that increase the alkalinity, i.e. that produce weak acid anions capable of buffering the acidification imposed by the CO2. Often, alkalinity increases as a result of anaerobic microbial activity, such as anaerobic oxidation of methane. However, on a long term the alteration of silicates, in particular, clay minerals, may be a more efficient mechanism of alkalinity production. Under altered temperature, pressure and porefluid composition at depth, clay minerals may change to thermodynamically more stable states, thereby increasing the alkalinity of the porefluid by partial leaching of Mg-(OH)2 and Ca-(OH)2 (e.g. Wallmann et al., 2008; Mavromatis et al., 2014). This alteration may even be enhanced by a high pCO2. Thus, silicate alteration can be essential for a long-term stabilization of volatile CO2 in the form of bicarbonate or may even induce precipitation of carbonate minerals, but these processes are not fully understood yet. The goal of this study is to simulate the alkalinity effect of silicate alteration under diagenetic conditions and high pCO2 by geochemical modeling. We are using the program PHREEQC (Parkhurst and Appelo, 2013) to generate high rock/fluid ratio characteristics for deep subsurface rock reservoirs. Since we are interested in the long-term evolution of diagenetic processes, over millions of years, we do not consider kinetics but calculate the theoretically possible equilibrium conditions. In a first step we are calculating the saturation state of different clay minerals

  10. Application of calcium carbonate slows down organic amendments mineralization in reclaimed soils

    NASA Astrophysics Data System (ADS)

    Zornoza, Raúl; Faz, Ángel; Acosta, José A.; Martínez-Martínez, Silvia; Ángeles Muñoz, M.

    2014-05-01

    A field experiment was set up in Cartagena-La Unión Mining District, SE Spain, aimed at evaluating the short-term effects of pig slurry (PS) amendment alone and together with marble waste (MW) on organic matter mineralization, microbial activity and stabilization of heavy metals in two tailing ponds. These structures pose environmental risk owing to high metals contents, low organic matter and nutrients, and null vegetation. Carbon mineralization, exchangeable metals and microbiological properties were monitored during 67 days. The application of amendments led to a rapid decrease of exchangeable metals concentrations, except for Cu, with decreases up to 98%, 75% and 97% for Cd, Pb and Zn, respectively. The combined addition of MW+PS was the treatment with greater reduction in metals concentrations. The addition of PS caused a significant increase in respiration rates, although in MW+PS plots respiration was lower than in PS plots. The mineralised C from the pig slurry was low, approximately 25-30% and 4-12% for PS and MW+PS treatments, respectively. Soluble carbon (Csol), microbial biomass carbon (MBC) and β-galactosidase and β-glucosidase activities increased after the application of the organic amendment. However, after 3 days these parameters started a decreasing trend reaching similar values than control from approximately day 25 for Csol and MBC. The PS treatment promoted highest values in enzyme activities, which remained high upon time. Arylesterase activity increased in the MW+PS treatment. Thus, the remediation techniques used improved soil microbiological status and reduced metal availability. The combined application of PS+MW reduced the degradability of the organic compounds. Keywords: organic wastes, mine soils stabilization, carbon mineralization, microbial activity.

  11. Acoustic Properties of Carbonate Rocks and Their Relation with Porosity and Mineral Composition

    NASA Astrophysics Data System (ADS)

    Scotellaro, C.; Vanorio, T.; Mavko, G.

    2007-12-01

    Carbonates are complex rocks characterized by a wide range of facies, texture, micro-structure, and rock fabrics. Understanding how this complexity affects the acoustic properties of carbonates is a key issue for interpreting and predicting changes in seismic images and acoustic log. Questions arise from the study of the porosity versus velocity relation for carbonate rocks which often consider the large scatter around the main velocity-porosity trend predominantly related to the porosity. We started a comprehensive laboratory study on carbonate rocks to understand how mineral composition, together with porosity, controls seismic wave propagation. The samples were collected capturing a wide range of porosities (from 1-52 percent) and different depositional environments in order to represent at best pore fabric and mineralogical heterogeneity in carbonates. Results of the hydraulic, transport, and acoustic properties of the collected samples were compared with those reported in the literature. The main results of this research show that a quite heterogeneous mineral composition of the samples (calcite, dolomite, and anhydrite), other than the pore type, controls the elastic behavior of carbonate rocks, and thus, the velocity-porosity trend. In particular, the samples showing the biggest departure from the general velocity-porosity trend show a non-negligible amount of anhydrite. Compared to calcite, anhydrite 1) causes rock softening and in turn, a decrease of P-wave velocity, because of the lower bulk modulus (k =56 GPa); 2) is characterized by a finer grain size (silt-size) which may create two elastic domains separated by a critical porosity approximately 30 percent.

  12. CarbFix I: Rapid CO2 mineralization in basalt for permanent carbon storage

    NASA Astrophysics Data System (ADS)

    Matter, J. M.; Stute, M.; Snæbjörnsdóttir, S.; Gíslason, S. R.; Oelkers, E. H.; Sigfússon, B.; Gunnarsson, I.; Aradottir, E. S.; Gunnlaugsson, E.; Broecker, W. S.

    2015-12-01

    Carbon dioxide mineralization via CO2-fluid-rock reactions provides the most permanent solution for geologic CO2 storage. Basalts, onshore or offshore, have the potential to store million metric tons of CO2 as (Ca, Mg, Fe) carbonates [1, 2]. However, as of today it was unclear how fast CO2 is converted to carbonate minerals in-situ in a basalt storage reservoir. The CarbFix I project in Iceland was designed to verify in-situ CO2 mineralization in basaltic rocks. Two injection tests were performed at the CarbFix I pilot injection site near the Hellisheidi geothermal power plant in 2012. 175 tons of pure CO2 and 73 tons of a CO2+H2S mixture were injection from January to March 2012 and in June 2013, respectively. The gases were injected fully dissolved in groundwater into a permeable basalt formation between 400 and 800 m depth using a novel CO2 injection system. Using conservative (SF6, SF5CF3) and reactive (14C) tracers, we quantitatively monitor and detect dissolved and chemically transformed CO2. Tracer breakthrough curves obtained from the first monitoring well indicate that the injected solution arrived in a fast short pulse and a late broad peak. Ratios of 14C/SF6, 14C/SF5CF3 or DIC/SF6 and DIC/SF5CF3 are significantly lower in the monitoring well compared to the injection well, indicating that the injected dissolved CO2 reacted. Mass balance calculations using the tracer data reveal that >95% of the injected CO2 has been mineralized over a period of two years. Evidence of carbonate precipitation has been found in core samples that were collected from the storage reservoir using wireline core drilling as well as in and on the submersible pump in the monitoring well. Results from the core analysis will be presented with emphasis on the CO2 mineralization. [1] McGrail et al. (2006) JGR 111, B12201; [2] Goldberg et al. (2008) PNAS 105(29), 9920-9925.

  13. Carbon Mineralization by Aqueous Precipitation for Beneficial Use of CO2 from Flue Gas

    SciTech Connect

    Devenney, Martin; Gilliam, Ryan; Seeker, Randy

    2014-06-01

    The objective of this project is to demonstrate an innovative process to mineralize CO2 from flue gas directly to reactive carbonates and maximize the value and versatility of its beneficial use products. The program scope includes the design, construction, and testing of a CO2 Conversion to Material Products (CCMP) Pilot Demonstration Plant utilizing CO2 from the flue gas of a power production facility in Moss Landing, CA as well as flue gas from coal combustion. This topical report covers Phase 2b, which is the construction phase of pilot demonstration subsystems that make up the integrated plant. The subsystems included are the mineralization subsystem, the Alkalinity Based on Low Energy (ABLE) subsystem, the waste calcium oxide processing subsystem, and the fiber cement board production subsystem. The fully integrated plant is now capable of capturing CO2 from various sources (gas and coal) and mineralizing into a reactive calcium carbonate binder and subsequently producing commercial size (4ftx8ft) fiber cement boards. The topical report provides a description of the “as built” design of these subsystems and the results of the commissioning activities that have taken place to confirm operability. At the end of Phase 2b, the CCMP pilot demonstration is fully ready for testing.

  14. Soil Carbon and Nitrogen Mineralization with Flexible Soil and Microbial C:N Ratios

    NASA Astrophysics Data System (ADS)

    Wang, G.; Mayes, M. A.; Thornton, P. E.; Hoffman, F. M.

    2014-12-01

    Microbial assimilation of C-N and the physicochemical protection of soil organic matter (SOM) play fundamental roles in regulating land-atmosphere interactions. However, these microbial and physicochemical processes are not explicitly represented in current region/global terrestrial ecosystem models, e.g., the Community Land Model (CLM). The lack of explicit representation of microbial pools and functions results in unrealistic fixed-C:N ratios in SOM pools currently in CLM. Thus current soil C-N model configuration is inadequate to model the effects of litter inputs or fertilization on soil carbon and nitrogen mineralization and linkages between plant litter C:N ratios and soil or microbial C:N ratios. We propose a coupled C-N model that allows for flexible C:N ratios in microbe and SOM pools and thus the ability to represent the decomposition response to fertilization and/or litter inputs with various C:N ratios. Our preliminary analysis has shown that the C:N ratios in SOM, dissolved organic matter (DOM), and microbial pools can be well constrained by the new C-N model and microbes regulate the C:N ratios in SOM and DOM pools. We will use this new model framework to evaluate the soil carbon and nitrogen mineralization processes under conditions of excess organic C, excess organic N, or limited mineral N.

  15. Carbon Isotope Systematics in Mineral-Catalyzed Hydrothermal Organic Synthesis Processes at High Temperature and Pressures

    NASA Technical Reports Server (NTRS)

    Fu, Qi; Socki, R. A.; Niles, Paul B.

    2011-01-01

    Observation of methane in the Martian atmosphere has been reported by different detection techniques. Reduction of CO2 and/or CO during serpentization by mineral surface catalyzed Fischer-Tropsch Type (FTT) synthesis may be one possible process responsible for methane generation on Mars. With the evidence a recent study has discovered for serpentinization in deeply buried carbon rich sediments, and more showing extensive water-rock interaction in Martian history, it seems likely that abiotic methane generation via serpentinization reactions may have been common on Mars. Experiments involving mineral-catalyzed hydrothermal organic synthesis processes were conducted at 750 C and 5.5 Kbars. Alkanes, alcohols and carboxylic acids were identified as organic compounds. No "isotopic reversal" of delta C-13 values was observed for alkanes or carboxylic acids, suggesting a different reaction pathway than polymerization. Alcohols were proposed as intermediaries formed on mineral surfaces at experimental conditions. Carbon isotope data were used in this study to unravel the reaction pathways of abiotic formation of organic compounds in hydrothermal systems at high temperatures and pressures. They are instrumental in constraining the origin and evolution history of organic compounds on Mars and other planets.

  16. Quantitative assessment of elemental carbon in the lungs of never smokers, cigarette smokers, and coal miners.

    PubMed

    Saxena, Rajiv K; McClure, Michael E; Hays, Michael D; Green, Francis H Y; McPhee, Laura J; Vallyathan, V; Gilmour, M Ian

    2011-01-01

    Inhalation exposure to particulates such as cigarette smoke and coal dust is known to contribute to the development of chronic lung disease. The purpose of this study was to estimate the amount of elemental carbon (EC) deposits from autopsied lung samples from cigarette smokers, miners, and control subjects and explore the relationship between EC level, exposure history, and the extent of chronic lung disease. The samples comprised three subgroups representing never smokers (8), chronic cigarette smokers (26), and coal miners (6). Following the dissolution of lung tissue, the extracted EC residue was quantified using a thermal-optical transmission (TOT) carbon analyzer. Mean EC levels in the lungs of the control group were 56.68 ± 24.86 (SD) μg/g dry lung weight. Respective mean EC values in lung samples from the smokers and coal miners were 449.56 ± 320.3 μg/g and 6678.2 ± 6162 μg/g. These values were significantly higher than those obtained from the never-smoker group. EC levels in the lung and pack-years of cigarette smoking correlated significantly, as did EC levels and the severity of small airway disease. This study provides one of the first quantitative assessments of EC in human lungs from populations at high relative risk for the development of chronic lung disease.

  17. Microbe-driven turnover offsets mineral-mediated storage of soil carbon under elevated CO2

    NASA Astrophysics Data System (ADS)

    Sulman, Benjamin N.; Phillips, Richard P.; Oishi, A. Christopher; Shevliakova, Elena; Pacala, Stephen W.

    2014-12-01

    The sensitivity of soil organic carbon (SOC) to changing environmental conditions represents a critical uncertainty in coupled carbon cycle-climate models. Much of this uncertainty arises from our limited understanding of the extent to which root-microbe interactions induce SOC losses (through accelerated decomposition or `priming') or indirectly promote SOC gains (via `protection' through interactions with mineral particles). We developed a new SOC model to examine priming and protection responses to rising atmospheric CO2. The model captured disparate SOC responses at two temperate free-air CO2 enrichment (FACE) experiments. We show that stabilization of `new' carbon in protected SOC pools may equal or exceed microbial priming of `old' SOC in ecosystems with readily decomposable litter and high clay content (for example, Oak Ridge). In contrast, carbon losses induced through priming dominate the net SOC response in ecosystems with more resistant litters and lower clay content (for example, Duke). The SOC model was fully integrated into a global terrestrial carbon cycle model to run global simulations of elevated CO2 effects. Although protected carbon provides an important constraint on priming effects, priming nonetheless reduced SOC storage in the majority of terrestrial areas, partially counterbalancing SOC gains from enhanced ecosystem productivity.

  18. Monitoring crude oil mineralization in salt marshes: Use of stable carbon isotope ratios

    SciTech Connect

    Jackson, A.W.; Pardue, J.H.; Araujo, R.

    1996-04-01

    In laboratory microcosms using salt marsh soils and in field trials, it was possible to monitor and quantify crude oil mineralization by measuring changes in CO{sub 2} {delta}{sup 13}C signatures and the rate of CO{sub 2} production. These values are easy to obtain and can be combined with simple isotope mass balance equations to determine the rate of mineralization from both the crude oil and indigenous carbon pool. Hydrocarbon degradation was confirmed by simultaneous decreases in alkane-, isoprenoid-, and PAH-hopane ratios. Additionally, the pseudo-first-order rate constants of alkane degradation (0.087 day{sup -1}) and CO{sub 2} production (0.082 day{sup -1}) from oil predicted by the {delta}{sup 13}C signatures were statistically indistinguishable. The addition of inorganic nitrogen and phosphate increased the rate of mineralization of crude oil in aerated microcosms but had no clear effect on in situ studies. This procedure appears to offer a means of definitively quantifying crude oil mineralization in a sensitive, inexpensive, and simple manner in environments with appropriate background {delta}{sup 13}C signatures. 23 refs., 5 figs., 1 tab.

  19. Mineral elements of subtropical tree seedlings in response to elevated carbon dioxide and nitrogen addition.

    PubMed

    Huang, Wenjuan; Zhou, Guoyi; Liu, Juxiu; Zhang, Deqiang; Liu, Shizhong; Chu, Guowei; Fang, Xiong

    2015-01-01

    Mineral elements in plants have been strongly affected by increased atmospheric carbon dioxide (CO2) concentrations and nitrogen (N) deposition due to human activities. However, such understanding is largely limited to N and phosphorus in grassland. Using open-top chambers, we examined the concentrations of potassium (K), calcium (Ca), magnesium (Mg), aluminum (Al), copper (Cu) and manganese (Mn) in the leaves and roots of the seedlings of five subtropical tree species in response to elevated CO2 (ca. 700 μmol CO2 mol(-1)) and N addition (100 kg N ha(-1) yr(-1)) from 2005 to 2009. These mineral elements in the roots responded more strongly to elevated CO2 and N addition than those in the leaves. Elevated CO2 did not consistently decrease the concentrations of plant mineral elements, with increases in K, Al, Cu and Mn in some tree species. N addition decreased K and had no influence on Cu in the five tree species. Given the shifts in plant mineral elements, Schima superba and Castanopsis hystrix were less responsive to elevated CO2 and N addition alone, respectively. Our results indicate that plant stoichiometry would be altered by increasing CO2 and N deposition, and K would likely become a limiting nutrient under increasing N deposition in subtropics. PMID:25794046

  20. Reflectance spectroscopy of oxalate minerals and relevance to Solar System carbon inventories

    NASA Astrophysics Data System (ADS)

    Applin, Daniel M.; Izawa, Matthew R. M.; Cloutis, Edward A.

    2016-11-01

    The diversity of oxalate formation mechanisms suggests that significant concentrations of oxalic acid and oxalate minerals could be widely distributed in the Solar System. We have carried out a systematic study of the reflectance spectra of oxalate minerals and oxalic acid, covering the 0.2-16 μm wavelength region. Our analyses show that oxalates exhibit unique spectral features that enable discrimination between oxalate phases and from other commonly occurring compounds, including carbonates, in all regions of the spectrum except for the visible. Using these spectral data, we consider the possible contribution of oxalate minerals to previously observed reflectance spectra of many objects throughout the Solar System, including satellites, comets, and asteroids. We find that polycarboxylic acid dimers and their salts may explain the reflectance spectra of many carbonaceous asteroids in the 3 μm spectral region. We suggest surface concentration of these compounds may be a type of space weathering from the photochemical and oxidative decomposition of the organic macromolecular material found in carbonaceous chondrites. The stability and ubiquity of these minerals on Earth, in extraterrestrial materials, and in association with biological processes make them useful for many applications in Earth and planetary sciences.

  1. Inter-relationships between corrosion and mineral-scale deposition in aqueous systems.

    PubMed

    Hodgkiess, T

    2004-01-01

    The processes of corrosion and scale deposition in natural and process waters are often linked and this paper considers a number of instances of interactions between the two phenomena. In some circumstances a scale layer (e.g. calcium carbonate) can be advantageously utilised as a corrosion-protection coating on components and this feature has been exploited for many decades in the conditioning of water to induce spontaneous precipitation of a scale layer upon the surfaces of engineering equipment. The electrochemical mechanisms associated with some corrosion and corrosion-control processes can promote alkaline-scale deposition directly upon component surfaces. This is a feature that can be exploited in the operation of cathodic protection (CP) of structures and components submerged in certain types of water (e.g. seawater). Similar phenomena can occur during bi-metallic corrosion and a case study, involving carbon steel/stainless steel couples in seawater, is presented. Additional complexities pertain during cyclic loading of submerged reinforced concrete members in which scale deposition may reduce the severity of fatigue stresses but can be associated with severe corrosion damage to embedded reinforcing steel. Also considered are scale-control/corrosion interactions in thermal desalination plant and an indirect consequence of the scale-control strategy on vapourside corrosion is discussed.

  2. Inter-relationships between corrosion and mineral-scale deposition in aqueous systems.

    PubMed

    Hodgkiess, T

    2004-01-01

    The processes of corrosion and scale deposition in natural and process waters are often linked and this paper considers a number of instances of interactions between the two phenomena. In some circumstances a scale layer (e.g. calcium carbonate) can be advantageously utilised as a corrosion-protection coating on components and this feature has been exploited for many decades in the conditioning of water to induce spontaneous precipitation of a scale layer upon the surfaces of engineering equipment. The electrochemical mechanisms associated with some corrosion and corrosion-control processes can promote alkaline-scale deposition directly upon component surfaces. This is a feature that can be exploited in the operation of cathodic protection (CP) of structures and components submerged in certain types of water (e.g. seawater). Similar phenomena can occur during bi-metallic corrosion and a case study, involving carbon steel/stainless steel couples in seawater, is presented. Additional complexities pertain during cyclic loading of submerged reinforced concrete members in which scale deposition may reduce the severity of fatigue stresses but can be associated with severe corrosion damage to embedded reinforcing steel. Also considered are scale-control/corrosion interactions in thermal desalination plant and an indirect consequence of the scale-control strategy on vapourside corrosion is discussed. PMID:14982172

  3. Atomic scale simulation of carbon nanotube nucleation from hydrocarbon precursors.

    PubMed

    Khalilov, Umedjon; Bogaerts, Annemie; Neyts, Erik C

    2015-12-22

    Atomic scale simulations of the nucleation and growth of carbon nanotubes is essential for understanding their growth mechanism. In spite of over twenty years of simulation efforts in this area, limited progress has so far been made on addressing the role of the hydrocarbon growth precursor. Here we report on atomic scale simulations of cap nucleation of single-walled carbon nanotubes from hydrocarbon precursors. The presented mechanism emphasizes the important role of hydrogen in the nucleation process, and is discussed in relation to previously presented mechanisms. In particular, the role of hydrogen in the appearance of unstable carbon structures during in situ experimental observations as well as the initial stage of multi-walled carbon nanotube growth is discussed. The results are in good agreement with available experimental and quantum-mechanical results, and provide a basic understanding of the incubation and nucleation stages of hydrocarbon-based CNT growth at the atomic level.

  4. Atomic scale simulation of carbon nanotube nucleation from hydrocarbon precursors

    PubMed Central

    Khalilov, Umedjon; Bogaerts, Annemie; Neyts, Erik C.

    2015-01-01

    Atomic scale simulations of the nucleation and growth of carbon nanotubes is essential for understanding their growth mechanism. In spite of over twenty years of simulation efforts in this area, limited progress has so far been made on addressing the role of the hydrocarbon growth precursor. Here we report on atomic scale simulations of cap nucleation of single-walled carbon nanotubes from hydrocarbon precursors. The presented mechanism emphasizes the important role of hydrogen in the nucleation process, and is discussed in relation to previously presented mechanisms. In particular, the role of hydrogen in the appearance of unstable carbon structures during in situ experimental observations as well as the initial stage of multi-walled carbon nanotube growth is discussed. The results are in good agreement with available experimental and quantum-mechanical results, and provide a basic understanding of the incubation and nucleation stages of hydrocarbon-based CNT growth at the atomic level. PMID:26691537

  5. Infrared and infrared emission spectroscopic study of selected magnesium carbonate minerals containing ferric iron--implications for the geosequestration of greenhouse gases.

    PubMed

    Frost, Ray L; Bahfenne, Silmarilly; Graham, Jessica

    2008-12-15

    The proposal to remove greenhouse gases by pumping liquid carbon dioxide several kilometres below ground level implies that many carbonate containing minerals will be formed. Among these minerals, the formation of two hydrotalcite-like minerals coalingite and brugnatellite is possible, thus necessitating a study of such minerals and their thermal stability. The two such carbonate-bearing minerals brugnatellite and coalingite have been characterised by a combination of infrared and infrared emission spectroscopy. Infrared emission spectroscopy is most useful to determine the stability of these minerals. The infrared spectra of the OH stretching region are characterised by OH and water stretching vibrations. Intense (CO3)(2-) symmetric and antisymmetric stretching vibrations support the concept that the carbonate ion is distorted in these minerals. The position of the water bending vibration indicates that the water is strongly hydrogen bonded in the mineral structure. IES spectra show the temperature range of the thermal stability of these minerals.

  6. Carbonate Mineral Formation under the Influence of Limestone-Colonizing Actinobacteria: Morphology and Polymorphism.

    PubMed

    Cao, Chengliang; Jiang, Jihong; Sun, Henry; Huang, Ying; Tao, Faxiang; Lian, Bin

    2016-01-01

    Microorganisms and their biomineralization processes are widespread in almost every environment on earth. In this work, Streptomyces luteogriseus DHS C014, a dominant lithophilous actinobacteria isolated from microbial mats on limestone rocks, was used to investigate its potential biomineralization to allow a better understanding of bacterial contributions to carbonate mineralization in nature. The ammonium carbonate free-drift method was used with mycelium pellets, culture supernatant, and spent culture of the strain. Mineralogical analyses showed that hexagonal prism calcite was only observed in the sub-surfaces of the mycelium pellets, which is a novel morphology mediated by microbes. Hemispheroidal vaterite appeared in the presence of spent culture, mainly because of the effects of soluble microbial products (SMP) during mineralization. When using the culture supernatant, doughnut-like vaterite was favored by actinobacterial mycelia, which has not yet been captured in previous studies. Our analyses suggested that the effects of mycelium pellets as a molecular template almost gained an advantage over SMP both in crystal nucleation and growth, having nothing to do with biological activity. It is thereby convinced that lithophilous actinobacteria, S. luteogriseus DHS C014, owing to its advantageous genetic metabolism and filamentous structure, showed good biomineralization abilities, maybe it would have geoactive potential for biogenic carbonate in local microenvironments. PMID:27148166

  7. Carbonate Mineral Formation under the Influence of Limestone-Colonizing Actinobacteria: Morphology and Polymorphism

    PubMed Central

    Cao, Chengliang; Jiang, Jihong; Sun, Henry; Huang, Ying; Tao, Faxiang; Lian, Bin

    2016-01-01

    Microorganisms and their biomineralization processes are widespread in almost every environment on earth. In this work, Streptomyces luteogriseus DHS C014, a dominant lithophilous actinobacteria isolated from microbial mats on limestone rocks, was used to investigate its potential biomineralization to allow a better understanding of bacterial contributions to carbonate mineralization in nature. The ammonium carbonate free-drift method was used with mycelium pellets, culture supernatant, and spent culture of the strain. Mineralogical analyses showed that hexagonal prism calcite was only observed in the sub-surfaces of the mycelium pellets, which is a novel morphology mediated by microbes. Hemispheroidal vaterite appeared in the presence of spent culture, mainly because of the effects of soluble microbial products (SMP) during mineralization. When using the culture supernatant, doughnut-like vaterite was favored by actinobacterial mycelia, which has not yet been captured in previous studies. Our analyses suggested that the effects of mycelium pellets as a molecular template almost gained an advantage over SMP both in crystal nucleation and growth, having nothing to do with biological activity. It is thereby convinced that lithophilous actinobacteria, S. luteogriseus DHS C014, owing to its advantageous genetic metabolism and filamentous structure, showed good biomineralization abilities, maybe it would have geoactive potential for biogenic carbonate in local microenvironments. PMID:27148166

  8. Organic carbon burial in the Cape Hatteras ocean margins. Relationships with mineral surfaces

    SciTech Connect

    Mayer, Lawrence M.

    2000-02-10

    This project examined controls on organic carbon preservation in ocean margin sediments around Cape Hatteras, USA. Grain size variation explained most variance in sedimentary organic carbon concentrations. Normalizing to grain surface areas allowed identification of areas of particularly high organic matter loading - i.e., the upper slope regions. Spatial variations in concentrations are influenced by redistribution of organoclay aggregates. This region has higher grain size-normalized organic carbon concentrations than any other ocean margin environment with an aerobic water column studied to date. Small scale variations in the Chesapeake Bay were also studied.

  9. Influence of carbon structure and mineral association of coals on their combustion characteristics for pulverized coal injection (PCI) application

    SciTech Connect

    Gupta, S.; Al-Omari, Y.; Sahajwalla, V.; French, D.

    2006-06-15

    The influence of carbon structure and mineral matter of three pulverized coals on their char characteristics including reactivity was studied under a range of combustion conditions in a drop tube furnace (DTF) and thermogravimetric (TGA) furnace for PCI application. Physical and chemical properties of coals and their combustion derivatives were characterized by automated reflectogram. X-ray diffraction, scanning electron microscope, and BET N{sub 2} adsorption. The QEMSCAN{asterisk} technique was used to characterize the heterogeneous nature of minerals of discrete coal particles. The TGA char reactivity was related to the proportion of coal particles displaying strong association of calcium/sulfur phases with carbon matrix to highlight the catalytic influence of minerals on char reactivity at low temperatures. The study suggested that during DTF combustion tests at 1200{sup o}C, char reaction rates might have been catalyzed by coal minerals, particularly due to illite and its association with carbon. Under the same combustion conditions, most of the coal minerals did not transform significantly to slag phases. Coal burnout was found to improve significantly in a combustion temperature range of 1200 to 1500{sup o}C. The improvement of coal burnout with temperature appeared to be influenced by coal properties, particularly as a function of the chemical nature of minerals, as well as the degree of associations with other minerals. The study implies that coals with similar mineral compositions might not necessarily reflect similar combustion behavior due to the differences in their associations with other phases.

  10. Carbonation of Wollastonite [CaSiO3] Under Hydrothermal Conditions During Exposure to Gaseous CO2: Implications for ex situ Mineralization

    NASA Astrophysics Data System (ADS)

    Chen, J.; Schaef, H. T.; Li, Q.; Vakifahmetoglu, C.; Riman, R. E.; Bowden, M. E.; Rosso, K. M.

    2011-12-01

    Because of its scale and complexity, reducing atmospheric concentrations of CO2 is considered one of the most challenging problems facing environmental scientists. Due to combustion of fossil fuels, primarily coal, concentrations of CO2 in the atmosphere will continue to increase into the foreseeable future. Consequently, research into potential storage options for CO2 is being explored including various ways to securely store CO2 underground. One alternative to this approach is ex situ mineralization, a process used to combine metal cation containing minerals and rocks with water and CO2 to produce solid-phase carbonates. Carbonation is a continuous natural process converting minerals into carbonate solids through direct interaction with atmospheric CO2 and moisture. Wollastonite [CaSiO3] is ideal for sequestering large amounts of CO2 in this fashion because of its high molar density of Ca2+ and easy availability. Wollastonite carbonation has been examined with in situ XRD to find optimal conditions for maximum conversion. Exposing fine grained natural wollastonite to hydrothermal conditions and gaseous CO2 resulted in over 40 wt% conversion during the first 100 minutes of reaction. Additional carbonation (~10 wt%) occurs more slowly over the remaining ~700 minutes of testing. As shown in Figure 1, the primary reflections of the CaCO3 polymorphs aragonite and calcite are visible after a few minutes of testing and continue to increase in intensity over time. Mineral quantification and total carbonation were obtained from the reacted material by pattern fitting (Rietveld Method) and TGA-MS. Variations in particle size, sample moisture, and length of exposure to hydrothermal conditions prior to pressurization with CO2 were found to influence relative amounts of calcite and aragonite formed. This has important implications for carbonation efficiency because although aragonite has a more compact structure and can therefore store CO2 in a more dense form, it is less

  11. eScience for molecular-scale simulations and the eMinerals project.

    PubMed

    Salje, E K H; Artacho, E; Austen, K F; Bruin, R P; Calleja, M; Chappell, H F; Chiang, G-T; Dove, M T; Frame, I; Goodwin, A L; Kleese van Dam, K; Marmier, A; Parker, S C; Pruneda, J M; Todorov, I T; Trachenko, K; Tyer, R P; Walker, A M; White, T O H

    2009-03-13

    We review the work carried out within the eMinerals project to develop eScience solutions that facilitate a new generation of molecular-scale simulation work. Technological developments include integration of compute and data systems, developing of collaborative frameworks and new researcher-friendly tools for grid job submission, XML data representation, information delivery, metadata harvesting and metadata management. A number of diverse science applications will illustrate how these tools are being used for large parameter-sweep studies, an emerging type of study for which the integration of computing, data and collaboration is essential.

  12. Sclerostin regulates release of bone mineral by osteocytes by induction of carbonic anhydrase 2.

    PubMed

    Kogawa, Masakazu; Wijenayaka, Asiri R; Ormsby, Renee T; Thomas, Gethin P; Anderson, Paul H; Bonewald, Lynda F; Findlay, David M; Atkins, Gerald J

    2013-12-01

    The osteocyte product sclerostin is emerging as an important paracrine regulator of bone mass. It has recently been shown that osteocyte production of receptor activator of NF-κB ligand (RANKL) is important in osteoclastic bone resorption, and we reported that exogenous treatment of osteocytes with sclerostin can increase RANKL-mediated osteoclast activity. There is good evidence that osteocytes can themselves liberate mineral from bone in a process known as osteocytic osteolysis. In the current study, we investigated sclerostin-stimulated mineral dissolution by human primary osteocyte-like cells (hOCy) and mouse MLO-Y4 cells. We found that sclerostin upregulated osteocyte expression of carbonic anhydrase 2 (CA2/Car2), cathepsin K (CTSK/Ctsk), and tartrate-resistant acid phosphatase (ACP5/Acp5). Because acidification of the extracellular matrix is a critical step in the release of mineral from bone, we further examined the regulation by sclerostin of CA2. Sclerostin stimulated CA2 mRNA and protein expression in hOCy and in MLO-Y4 cells. Sclerostin induced a decrease in intracellular pH (pHi) in both cell types as well as a decrease in extracellular pH (pHo) and the release of calcium ions from mineralized substrate. These effects were reversed in the co-presence of the carbonic anhydrase inhibitor, acetozolamide. Car2-siRNA knockdown in MLO-Y4 cells significantly inhibited the ability of sclerostin to both reduce the pHo and release calcium from a mineralized substrate. Knockdown in MLO-Y4 cells of each of the putative sclerostin receptors, Lrp4, Lrp5 and Lrp6, using siRNA, inhibited the sclerostin induction of Car2, Catk and Acp5 mRNA, as well as pHo and calcium release. Consistent with this activity of sclerostin resulting in osteocytic osteolysis, human trabecular bone samples treated ex vivo with recombinant human sclerostin for 7 days exhibited an increased osteocyte lacunar area, an effect that was reversed by the co-addition of acetozolamide. These findings

  13. Fluxes of dissolved organic matter and mineral weathering products from Corn Belt landscapes dominated by subsurface drainage: large-scale soil and hydrologic change

    NASA Astrophysics Data System (ADS)

    Jelinski, N. A.; Yoo, K.; Strock, J.; Dalzell, B. J.; Finlay, J. C.

    2011-12-01

    The human alteration of agricultural landscapes is one of the most important factors in pedologic and geomorphic change, and can influence hydrology and aquatic chemistry at large scales. Most of the Midwestern Corn Belt that is currently dominated by subsurface tile drainage (such as southern Minnesota) was historically prairie and wetland which had hydrologic flow-paths through organic-rich surface soil horizons, a condition that favored the export of dissolved organic matter. When hydrology is altered through subsurface drainage, adsorption of organic materials to mineral surfaces and increases in mineral weathering may result because more water is flowing through subsurface mineral soils. We suggest that the alteration of hydrologic flowpaths in agricultural landscapes can dramatically alter the rate of mineral weathering as well as surface export of weathering products and dissolved organic matter. This could be at least one contributing factor to observed increases in Mississippi River alkalinity over the past four decades. Here, we examine trends in dissolved organic carbon, total dissolved nitrogen, dissolved organic nitrogen, total suspended solids, and indicators of mineral weathering (Si, Ca, Na, K) from subsurface drainage systems located in southwestern MN. Then, using a simple conceptual model, we estimate the effects of subsurface drainage on the regional fluxes of these parameters and present directions for future research.

  14. Control of calcium carbonate polymorphism and morphology through biomimetic mineralization by means of nanotechnology.

    PubMed

    Ichikawa, Kazuhiko; Shimomura, Noriyuki; Yamada, Masanori; Ohkubo, Naoki

    2003-07-21

    In vitro biomimetic mineralization by means of nanotechnology allows the formation of calcium carbonate polymorphs at low temperatures (<25 degrees C) under a CO(2) atmosphere of 500-1500 ppm. A two-dimensional zinc-ion ordered array (zinc array), which acts as an active-site mimic of carbonic anhydrase, has been prepared by immersing the self-organized monolayer of 3-(2-imidazolin-1-y)propyltriethosilane on mica (ImSi substrate) into aqueous zinc solution. The zinc array mounted on the ImSi substrate catalyzed the conversion from CO(2) to HCO(3) (-), and accelerated the formation of calcium carbonate. In situ X-ray diffraction data of the formed calcium carbonate on the poly(L-aspartate)-coated chitin substrate (pAsp substrate), with calcium ion-recognition sites, demonstrated that the interaction between the zinc array and pAsp substrates formed both vaterite and calcite at low temperature (15 degrees C) and mainly vaterite at 25 degrees C; this interaction also controlled the morphology of calcium carbonate formed on pAsp substrate.

  15. Oxygen and carbon isotope ratios of hydrothermal minerals from Yellowstone drill cores

    USGS Publications Warehouse

    Sturchio, N.C.; Keith, T.E.C.; Muehlenbachs, K.

    1990-01-01

    Oxygen and carbon isotope ratios were measured for hydrothermal minerals (silica, clay and calcite) from fractures and vugs in altered rhyolite, located between 28 and 129 m below surface (in situ temperatures ranging from 81 to 199??C) in Yellowstone drill holes. The purpose of this study was to investigate the mechanism of formation of these minerals. The ??18O values of the thirty-two analyzed silica samples (quartz, chalcedony, ??-cristobalite, and ??-cristobalite) range from -7.5 to +2.8???. About one third of the silica 7samples have ??18O values that are consistent with isotopic equilibrium with present thermal waters; most of the other silica samples appear to have precipitated from water enriched in 18O (up to 4.7???) relative to present thermal water, assuming precipitation at present in situ temperatures. Available data on fluid-inclusion homogenization temperatures in hydrothermal quartz indicate that silica precipitation occurred mostly at temperatures above those measured during drilling and imply that 15O enrichments in water during silica precipitation were generally larger than those estimated from present conditions. Similarly, clay minerals (celadonite and smectite) have ??18O values higher (by 3.5 to 7.9???) than equilibrium values under present conditions. In contrast, all eight analyzed calcite samples are close to isotopic equilibrium with present thermal waters. The frequent incidence of apparent 18O enrichment in thermal water from which the hydrothermal minerals precipitated may indicate that a higher proportion of strongly 18O-enriched deep hydrothermal fluid once circulated through shallow portions of the Yellowstone system, or that a recurring transient 18O-enrichment effect occurs at shallow depths and is caused either by sudden decompressional boiling or by isotopic exchange at low water/rock ratios in new fractures. The mineralogy and apparent 18O enrichments of hydrothermal fracture-filling minerals are consistent with deposition

  16. [Characteristics of soil organic carbon mineralization at different temperatures in paddy soils under long-term fertilization].

    PubMed

    Lin, Shan; Chen, Tao; Zhao, Jin-Song; Xiang, Rong-Biao; Hu, Rong-Gui; Zhang, Shui-Qing; Wang, Mi-Lan; Lu, Zhao-Qi

    2014-05-01

    Dynamics of soil organic carbon mineralization affected by long-term fertilizations and temperature in relation to different soil carbon fractions were investigated in paddy soils. Soil samples were collected from the plough layer of 3 long-term national experimental sites in Xinhua, Ningxiang and Taojiang counties of Hunan Province. Mineralization of soil organic C was estimated by 33-day aerobic incubation at different temperatures of 10, 20 and 30 degrees C. The results showed that the rates of CO2 production were higher during the earlier phase (0-13 d) in all treatments, and then decreased according to a logarithm function. Higher incubation temperature strengthened C mineralization in the different treatments. The quantities of cumulative CO2 production in NPK with manure or straw treatments were greater than in inorganic fertilizers treatments. The Q10 values in the different soil treatments ranged from 1.01-1.53. There were significantly positive correlations between the Q10 values and soil total organic carbon (TOC), easy oxidation organic carbon (EOOC), humic acid carbon (C(HA)), fulvic acid carbon (CFA). The cumulative amount of mineralized C was significantly positively correlated with microbial biomass carbon (MBC) at 10 and 20 degrees C, but not significantly at 30 degrees C. Significant correlations were found between the cumulative amount of mineralized C and different soil carbon fractions and C(HA)/C(FA). The correlations of differ- ent soil carbon fractions with the ratio of cumulative mineralized C to TOC were negatively correlated at 10 degrees C, but not significantly at 20 and 30 degrees C. These results suggested that the application of NPK with manure or straw would be helpful to increase the sequestration of C in paddy soils and reduce its contribution of CO2 release in the atmosphere. PMID:25129934

  17. [Characteristics of soil organic carbon mineralization at different temperatures in paddy soils under long-term fertilization].

    PubMed

    Lin, Shan; Chen, Tao; Zhao, Jin-Song; Xiang, Rong-Biao; Hu, Rong-Gui; Zhang, Shui-Qing; Wang, Mi-Lan; Lu, Zhao-Qi

    2014-05-01

    Dynamics of soil organic carbon mineralization affected by long-term fertilizations and temperature in relation to different soil carbon fractions were investigated in paddy soils. Soil samples were collected from the plough layer of 3 long-term national experimental sites in Xinhua, Ningxiang and Taojiang counties of Hunan Province. Mineralization of soil organic C was estimated by 33-day aerobic incubation at different temperatures of 10, 20 and 30 degrees C. The results showed that the rates of CO2 production were higher during the earlier phase (0-13 d) in all treatments, and then decreased according to a logarithm function. Higher incubation temperature strengthened C mineralization in the different treatments. The quantities of cumulative CO2 production in NPK with manure or straw treatments were greater than in inorganic fertilizers treatments. The Q10 values in the different soil treatments ranged from 1.01-1.53. There were significantly positive correlations between the Q10 values and soil total organic carbon (TOC), easy oxidation organic carbon (EOOC), humic acid carbon (C(HA)), fulvic acid carbon (CFA). The cumulative amount of mineralized C was significantly positively correlated with microbial biomass carbon (MBC) at 10 and 20 degrees C, but not significantly at 30 degrees C. Significant correlations were found between the cumulative amount of mineralized C and different soil carbon fractions and C(HA)/C(FA). The correlations of differ- ent soil carbon fractions with the ratio of cumulative mineralized C to TOC were negatively correlated at 10 degrees C, but not significantly at 20 and 30 degrees C. These results suggested that the application of NPK with manure or straw would be helpful to increase the sequestration of C in paddy soils and reduce its contribution of CO2 release in the atmosphere.

  18. Carbon-14 time scale extended: comparison of chronologies.

    PubMed

    Grootes, P M

    1978-04-01

    Thermal diffusion isotopic enrichment of carbon-14 has extended the radiocarbon dating range to about 75,000 years ago. Twenty-eight samples obtained up to June 1976, mainly from northwest Europe, were dated. Consideration of the basic assumptions of carbon-14 dating and of the sources of contamination indicates that the ages are generally reliable. Together with the pollen analytic and stratigraphic the dates yield a more detailed radiocarbon time scale for climatic variations in northwest Europe, showing three early glacial interstades. The radiocarbon time scale agrees with the Camp Century chronology and with the thorium-230 ages of corals representing high sea level stands on New Guinea. Ther is a discrepancy between the radiocarbon time scale and the deep-sea chronology, which may be due to correlation errors. With a modified interpretation of the correlation, all four time scales agree within the estimated experimental uncertainties of the dating techniques used.

  19. Geochemical Evidence for Subduction in the Early Archaean from Quartz-Carbonate-Fuchsite Mineralization, Isua Supracrustal Belt, West Greenland

    NASA Astrophysics Data System (ADS)

    Pope, E. C.; Rosing, M. T.; Bird, D. K.

    2011-12-01

    , before migrating up crustal-scale vertical fracture zones. Thus, the presence of quartz-carbonate-fuchsite mineralization in the Isua supracrustal belt and other Archaean-age deposits provides strong evidence for the existence of modern-style subduction as early as 3.8 Ga.

  20. Approaches for Landscape-scale Forest Carbon Assessment

    NASA Astrophysics Data System (ADS)

    Birdsey, R.; Pan, Y.; Wayson, C.; Johnson, K. D.; Zhang, F.; Chen, J. M.; Pinto, N.; Cook, B. D.; Masek, J. G.

    2011-12-01

    Increasingly, public and private forest landowners need to estimate their carbon stocks and analyze the impacts of alternate management plans. Here we describe approaches designed to work at landscape scales: one involves estimating carbon stocks from existing Forest Inventory and Analysis (FIA) data; another involves downscaling results from a continental-scale biogeochemistry model known as InTEC; and the third uses LiDAR remote sensing to provide high-resolution biomass maps. Combining FIA data with a biogeochemistry model gives the most useful information for analyzing causes of historical trends, while the biomass maps support implementation of management decisions. These approaches are illustrated by pilot studies in the Eastern U.S. Analysis of FIA data for Northern Wisconsin revealed that private landowners held more than half of the forest carbon but that the rate of carbon sequestration had slowed dramatically over two decades. Causes of the decline were hypothesized to include increased harvesting, aging forests, and increasing disturbances. The InTEC model for the same region revealed trends over a much longer historical period as well as providing information about changes in soil C that are lacking in the FIA data analysis. The effects of long-term forest age dynamics and higher interannual climate variability became evident, and there is evidence of a significant contribution to net sequestration from increasing soil C stocks. Using this information base, we identified several ways to increase landscape-scale average forest carbon stocks: allow some forests to reach full maturity and highest carbon stocks; manage other forests to maximize carbon uptake and transfer of harvested carbon into wood products; and avoid conversion of existing forests to nonforest land uses. Strategic implementation of these kinds of management decisions can be facilitated with high-resolution biomass maps.

  1. A Global Scale Scenario for Prebiotic Chemistry: Silica-Based Self-Assembled Mineral Structures and Formamide.

    PubMed

    Saladino, Raffaele; Botta, Giorgia; Bizzarri, Bruno Mattia; Di Mauro, Ernesto; Garcia Ruiz, Juan Manuel

    2016-05-17

    The pathway from simple abiotically made organic compounds to the molecular bricks of life, as we know it, is unknown. The most efficient geological abiotic route to organic compounds results from the aqueous dissolution of olivine, a reaction known as serpentinization (Sleep, N.H., et al. (2004) Proc. Natl. Acad. Sci. USA 101, 12818-12822). In addition to molecular hydrogen and a reducing environment, serpentinization reactions lead to high-pH alkaline brines that can become easily enriched in silica. Under these chemical conditions, the formation of self-assembled nanocrystalline mineral composites, namely silica/carbonate biomorphs and metal silicate hydrate (MSH) tubular membranes (silica gardens), is unavoidable (Kellermeier, M., et al. In Methods in Enzymology, Research Methods in Biomineralization Science (De Yoreo, J., Ed.) Vol. 532, pp 225-256, Academic Press, Burlington, MA). The osmotically driven membranous structures have remarkable catalytic properties that could be operating in the reducing organic-rich chemical pot in which they form. Among one-carbon compounds, formamide (NH2CHO) has been shown to trigger the formation of complex prebiotic molecules under mineral-driven catalytic conditions (Saladino, R., et al. (2001) Biorganic & Medicinal Chemistry, 9, 1249-1253), proton irradiation (Saladino, R., et al. (2015) Proc. Natl. Acad. Sci. USA, 112, 2746-2755), and laser-induced dielectric breakdown (Ferus, M., et al. (2015) Proc Natl Acad Sci USA, 112, 657-662). Here, we show that MSH membranes are catalysts for the condensation of NH2CHO, yielding prebiotically relevant compounds, including carboxylic acids, amino acids, and nucleobases. Membranes formed by the reaction of alkaline (pH 12) sodium silicate solutions with MgSO4 and Fe2(SO4)3·9H2O show the highest efficiency, while reactions with CuCl2·2H2O, ZnCl2, FeCl2·4H2O, and MnCl2·4H2O showed lower reactivities. The collections of compounds forming inside and outside the tubular membrane are

  2. A Global Scale Scenario for Prebiotic Chemistry: Silica-Based Self-Assembled Mineral Structures and Formamide

    PubMed Central

    2016-01-01

    The pathway from simple abiotically made organic compounds to the molecular bricks of life, as we know it, is unknown. The most efficient geological abiotic route to organic compounds results from the aqueous dissolution of olivine, a reaction known as serpentinization (Sleep, N.H., et al. (2004) Proc. Natl. Acad. Sci. USA 101, 12818–12822). In addition to molecular hydrogen and a reducing environment, serpentinization reactions lead to high-pH alkaline brines that can become easily enriched in silica. Under these chemical conditions, the formation of self-assembled nanocrystalline mineral composites, namely silica/carbonate biomorphs and metal silicate hydrate (MSH) tubular membranes (silica gardens), is unavoidable (Kellermeier, M., et al. In Methods in Enzymology, Research Methods in Biomineralization Science (De Yoreo, J., Ed.) Vol. 532, pp 225–256, Academic Press, Burlington, MA). The osmotically driven membranous structures have remarkable catalytic properties that could be operating in the reducing organic-rich chemical pot in which they form. Among one-carbon compounds, formamide (NH2CHO) has been shown to trigger the formation of complex prebiotic molecules under mineral-driven catalytic conditions (Saladino, R., et al. (2001) Biorganic & Medicinal Chemistry, 9, 1249–1253), proton irradiation (Saladino, R., et al. (2015) Proc. Natl. Acad. Sci. USA, 112, 2746–2755), and laser-induced dielectric breakdown (Ferus, M., et al. (2015) Proc Natl Acad Sci USA, 112, 657–662). Here, we show that MSH membranes are catalysts for the condensation of NH2CHO, yielding prebiotically relevant compounds, including carboxylic acids, amino acids, and nucleobases. Membranes formed by the reaction of alkaline (pH 12) sodium silicate solutions with MgSO4 and Fe2(SO4)3·9H2O show the highest efficiency, while reactions with CuCl2·2H2O, ZnCl2, FeCl2·4H2O, and MnCl2·4H2O showed lower reactivities. The collections of compounds forming inside and outside the tubular

  3. A Global Scale Scenario for Prebiotic Chemistry: Silica-Based Self-Assembled Mineral Structures and Formamide.

    PubMed

    Saladino, Raffaele; Botta, Giorgia; Bizzarri, Bruno Mattia; Di Mauro, Ernesto; Garcia Ruiz, Juan Manuel

    2016-05-17

    The pathway from simple abiotically made organic compounds to the molecular bricks of life, as we know it, is unknown. The most efficient geological abiotic route to organic compounds results from the aqueous dissolution of olivine, a reaction known as serpentinization (Sleep, N.H., et al. (2004) Proc. Natl. Acad. Sci. USA 101, 12818-12822). In addition to molecular hydrogen and a reducing environment, serpentinization reactions lead to high-pH alkaline brines that can become easily enriched in silica. Under these chemical conditions, the formation of self-assembled nanocrystalline mineral composites, namely silica/carbonate biomorphs and metal silicate hydrate (MSH) tubular membranes (silica gardens), is unavoidable (Kellermeier, M., et al. In Methods in Enzymology, Research Methods in Biomineralization Science (De Yoreo, J., Ed.) Vol. 532, pp 225-256, Academic Press, Burlington, MA). The osmotically driven membranous structures have remarkable catalytic properties that could be operating in the reducing organic-rich chemical pot in which they form. Among one-carbon compounds, formamide (NH2CHO) has been shown to trigger the formation of complex prebiotic molecules under mineral-driven catalytic conditions (Saladino, R., et al. (2001) Biorganic & Medicinal Chemistry, 9, 1249-1253), proton irradiation (Saladino, R., et al. (2015) Proc. Natl. Acad. Sci. USA, 112, 2746-2755), and laser-induced dielectric breakdown (Ferus, M., et al. (2015) Proc Natl Acad Sci USA, 112, 657-662). Here, we show that MSH membranes are catalysts for the condensation of NH2CHO, yielding prebiotically relevant compounds, including carboxylic acids, amino acids, and nucleobases. Membranes formed by the reaction of alkaline (pH 12) sodium silicate solutions with MgSO4 and Fe2(SO4)3·9H2O show the highest efficiency, while reactions with CuCl2·2H2O, ZnCl2, FeCl2·4H2O, and MnCl2·4H2O showed lower reactivities. The collections of compounds forming inside and outside the tubular membrane are

  4. Production Scale-Up or Activated Carbons for Ultracapacitors

    SciTech Connect

    Dr. Steven D. Dietz

    2007-01-10

    Transportation use accounts for 67% of the petroleum consumption in the US. Electric and hybrid vehicles are promising technologies for decreasing our dependence on petroleum, and this is the objective of the FreedomCAR & Vehicle Technologies Program. Inexpensive and efficient energy storage devices are needed for electric and hybrid vehicle to be economically viable, and ultracapacitors are a leading energy storage technology being investigated by the FreedomCAR program. The most important parameter in determining the power and energy density of a carbon-based ultracapacitor is the amount of surface area accessible to the electrolyte, which is primarily determined by the pore size distribution. The major problems with current carbons are that their pore size distribution is not optimized for liquid electrolytes and the best carbons are very expensive. TDA Research, Inc. (TDA) has developed methods to prepare porous carbons with tunable pore size distributions from inexpensive carbohydrate based precursors. The use of low-cost feedstocks and processing steps greatly lowers the production costs. During this project with the assistance of Maxwell Technologies, we found that an impurity was limiting the performance of our carbon and the major impurity found was sulfur. A new carbon with low sulfur content was made and found that the performance of the carbon was greatly improved. We also scaled-up the process to pre-production levels and we are currently able to produce 0.25 tons/year of activated carbon. We could easily double this amount by purchasing a second rotary kiln. More importantly, we are working with MeadWestvaco on a Joint Development Agreement to scale-up the process to produce hundreds of tons of high quality, inexpensive carbon per year based on our processes.

  5. Minerals vs. Microbes: Biogeochemical Controls on Carbon Storage in Humid Tropical Forest Soils

    NASA Astrophysics Data System (ADS)

    Hall, S. J.; Silver, W. L.

    2012-12-01

    Humid tropical forest soils contain a substantial portion (~500 Pg) of the terrestrial carbon (C) pool, yet their response to climate change remains unclear due to mechanistic uncertainty in the biogeochemical controls on soil C storage in these ecosystems. Poorly-crystalline minerals have long been known to stabilize soil C, but few studies have explored their relative importance in comparison with other likely controls such as rhizosphere processes, oxygen deficiency (anaerobiosis), and C quality. We examined relationships among soil C and a suite of biogeochemical variables measured in 162 samples from surface soils (ultisols and oxisols) collected over scales of landforms to landscapes (m - km) in the Luquillo Experimental Forest, Puerto Rico. We measured iron (Fe), aluminum (Al), and manganese (Mn) oxides in 0.5M hydrochloric acid (HCl), sodium citrate/ascorbic acid (CA), and citrate/dithionite (CD) extractions, along with clay content, root biomass, C quality (C/N ratios), and anaerobiosis using HCl-extractable reduced iron (Fe(II)) concentrations as a proxy. We used mixed-effects models to compare the relative importance of the above variables (normalized by mean and standard deviation) as predictors of soil C, with random effects to account for spatial structure. Poorly-crystalline Al oxide concentrations (CA extraction), soil C/N ratio, and Fe(II) concentrations each had highly significant (p < 0.0001) positive relationships with soil C concentrations that conveyed equivalent explanatory power, assessed by comparing standardized regression coefficients. The optimal mixed model explained 82 % of the variation of the residual sum of squares of soil C concentrations, which varied between 2 - 20 % C among samples. Fine root biomass had a weak but significantly positive association with soil C concentrations (p < 0.05), while crystalline Fe oxide concentrations (CD extraction) displayed a negative correlation (p < 0.01), and clay contents had no significant

  6. Linking carbon isotopes and carbon-water exchange of plants across different scales

    NASA Astrophysics Data System (ADS)

    Seibt, U.; Rajabi, A.; Griffiths, H.; Berry, J.

    2007-12-01

    The anthropogenic rise in atmospheric CO2 levels may lead to increased photosynthetic uptake while transpiration rates remain constant or are reduced. Changes in plant regulation of carbon uptake and water loss also affect the carbon isotope signatures of plant material. But environmental conditions may change in addition to CO2. The resulting combination of factors can have different effects on the carbon-water balance of plants, and their carbon isotope signatures. For example, changes in evaporative demand alter the ratio of total carbon gain to water loss of a plant, the parameter of interest from the point of view of the atmosphere. Isotope values, on the other hand, also reflect physiological properties, including C:N allocation to carboxylation and internal conductance. Here, we explore how these factors shape carbon isotope signatures as well as carbon and water fluxes from leaf to ecosystem levels, and across diurnal to decadal timescales. We present new data to illustrate that a correlation between carbon isotope signatures and carbon-water exchange at the leaf level may not be passed on to the whole plant level. We then use a simple coupled model to analyse the relationships between carbon-water fluxes and isotope values. The model calculates gas exchange and carbon isotope signatures at the leaf level (for comparison with leaf samples), and propagates both gas exchange and isotope values to long- term trends in carbon-water exchange and carbon isotope signatures at the canopy scale (for comparison with samples of annual resolution). This approach is useful for exploring the sensitivity of carbon isotope ratios and carbon-water exchange of plants to simultaneous changes in external and internal factors, for example when interpreting trends in carbon isotope signatures obtained from tree rings.

  7. Direct mineral carbonation of steelmaking slag for CO2 sequestration at room temperature.

    PubMed

    Rushendra Revathy, T D; Palanivelu, K; Ramachandran, A

    2016-04-01

    Rapid increase of CO2 concentration in the atmosphere has forced the international community towards adopting actions to restrain from the impacts of climate change. Moreover, in India, the dependence on fossil fuels is projected to increase in the future, implying the necessity of capturing CO2 in a safe manner. Alkaline solid wastes can be utilized for CO2 sequestration by which its disposal issues in the country could also be met. The present work focuses to study direct mineral carbonation of steelmaking slag (SS) at room temperature and low-pressure conditions (<10 bar). Direct mineral carbonation of SS was carried out in a batch reactor with pure CO2 gas. The process parameters that may influence the carbonation of SS, namely, CO2 gas pressure, liquid to solid ratio (L/S) and reaction time were also studied. The results showed that maximum sequestration of SS was attained in the aqueous route with a capacity of 82 g of CO2/kg (6 bar, L/S ratio of 10 and 3 h). In the gas-solid route, maximum sequestration capacity of about 11.1 g of CO2/kg of SS (3 bar and 3 h) was achieved indicating that aqueous route is the better one under the conditions studied. These findings demonstrate that SS is a promising resource and this approach could be further developed and used for CO2 sequestration in the country. The carbonation process was evidenced using FT-IR, XRD, SEM and TG analysis.

  8. An integrated experimental program to understanding leakage from geologic carbon sequestration sites across scales

    NASA Astrophysics Data System (ADS)

    Clarens, A. F.; Wang, S.; Liang, B.; Peters, C. A.; Fitts, J. P.; Deng, H.; Ellis, B. R.

    2012-12-01

    Leakage from the deep saline aquifers targeted in geologic carbon sequestration (GCS) is difficult to study because of heterogeneities in the structure and chemical composition of the subsurface along with the characteristically large length scales and resulting phase changes that are involved. The chemical and physical processes that govern the buoyancy driven flow of CO2 are important to understand because leakage could undermine the nominal goal of GCS to keep CO2 out of the atmosphere. Here we report on a partnership between Princeton and the University of Virginia (UVa) to study these processes experimentally across multiple length scales in both porous media and fractured caprocks. Experiments span length scales from microns to meters, and the processes studied range from geochemical reactions to the physics of flow. In this presentation, we summarize the suite of experiments that are underway and present recent findings. We seek to demonstrate that this coordinated, multi-disciplinary, multi-scale research collaboration will lead to improved understanding of the fundamental processes that may control the permanence of stored CO2. At UVa, the aim has been to characterize the interfacial properties that will impact buoyancy driven flows in porous media. Contact angle experiments at the CO2-brine-mineral interface have been carried out on silica, carbonate and clay minerals. These results will be used to inform how mineral heterogeneity influences multiphase buoyant flow through sandstones in which pore surfaces are frequently coated by diagenetic clays. Although all minerals are water wetting, the pH point of zero charge was found to be a good predictor of maximum wetting for a solid surface. When the CO2 was not in equilibrium with the brine, hysteric effects were observed as CO2 dissolved into the bulk fluid. Some of this is associated with contact line pinning on certain surfaces that may be driven by salt precipitation near the phase interface. Contact

  9. Mineral Surface Control of Organic Carbon Burial: Secular Rise of Clay Mineral Deposition in the Precambrian and the Rise of Oxygen

    NASA Astrophysics Data System (ADS)

    Kennedy, M. J.; Droser, M. L.; Mayer, L.; Pevear, D.

    2004-12-01

    Accumulation of oxygen in the earth's atmosphere requires burial of organic matter in marine sediments. Today, the major mode of organic carbon burial is in association with detrital pedogenic clay minerals which serve to protect organic matter against biological oxidation during burial in marine sediments. The bulk of detrital clays that are ultimately deposited in marine sediments are formed in biologically active soils that require plant processes to retain water, concentrate weathering produced solutes, stablize soils, and provide an adsorptive media. At some point in Earth history before the colonization of land surfaces by plants and the formation of biotic soils, clay mineral surface limitation may have severely reduced the preservation potential of organic carbon during burial. An important consequence of this would have also been a reduced flux of oxygen to the atmosphere because organic carbon and oxygen release are coupled. Multiple independent lines of evidence indicate a significant change in continental weathering and pedogenic clay mineral formation and establishment of the `clay factory' that coincides with colonization of land surfaces by primitive plant like organisms in the late Precambrian. The enhanced burial efficiency that would have accompanied the shift to the modern mode of detrital pedogenic clay hosted carbon burial would have driven an increase in oxygen levels toward present values. Evidence suggests that this rise in oxygen occurred just prior to the advent of the first complex animals in the Ediacaran.

  10. Soil carbon responses to environmental change across temporal scales

    NASA Astrophysics Data System (ADS)

    Sierra, Carlos; Müller, Markus; Metzler, Holger

    2016-04-01

    Different biotic and abiotic factors modify the rates of soil carbon cycling at a variety of temporal scales, posing challenges in determining appropriate model abstractions to represent soil carbon dynamics in the context of global environmental change. Although a large variety of models of soil organic matter dynamics have been proposed previously, it is difficult to compare different model structures and their scale of application. We present here a mathematical framework that can be used to synthesize models with different structure, i.e. number of distinctive pools, their cycling rates and their connection. This framework can also be used to identify the scale of operability of a model and how carbon stocks and respiration fluxes would respond to external perturbations. In this contribution, we present the main concepts behind our mathematical framework and how through eigenvalue analyses we can identify the scale of operability of a model. We also present an analysis of the potential sensitivity of soil carbon stocks to changes in temperature and moisture, and identify regions with larger sensitivities to climate change. Although different models provide very diverse responses, we predict larger sensitivities of soil C stocks in humid tropical regions to increases in temperature and decreases in soil moisture.

  11. Effect of Additives and pH on the Formation of Carbonate Mineral by CO2 Sequestration of Cement Paste

    NASA Astrophysics Data System (ADS)

    Lee, J. H.; Hwang, J.; Lee, H.; Son, B. S.; Oh, J.

    2015-12-01

    CO2 in the atmosphere causes a global warming that is a big issue nowadays. Many studies of CO2 capture and storage (CCS) technologies have been studied all over the world. Waste cement is a good source for aqueous carbonation because it is rich in calcium. Therefore, this study was performed to develop the aqueous carbonation method for waste cement powder. Cement paste was made with water/cement ratio of 6:4 and cured for 28 days in water bath. The cement paste was pulverized into a fine powder sizing less than 0.15 mm. To study effect of additives and pH on the formation of carbonate minerals, aqueous carbonation experiments were conducted. The mineral compositions and morphology of carbonate mineral were identified by XRD and SEM/EDS analysis. 1.0 M NaCl and 0.25 M MgCl2 were applied as additives. Aqueous carbonation experiment was conducted with injecting pure CO2 gas (99.9%) to a reactor containing 200 ㎖ of reacting solution. The pH of reacting solution was controled to determine formational condition of carbonate minerals. In 0.25 M MgCl2 solution, calcite was dominant mineral at high pH. More aragonite, however, formed as decreasing pH of solution with injection of CO2. The presence of Mg2+ in solution makes aragonite more dominant than calcite. Aragonite was mainly formed at the high pH of solution with 1.0 M NaCl additive, whereas calcite was more preponderant mineral than aragonite as falling pH. It show that unstable aragonite transformed to calcite as decreasing pH. In no additive solution, vaterite was dominantly formed at the initial stage of experiement, but unstable vaterite transformed to well crystallized calcite with further carbonation.

  12. Distinct temperature sensitivity of soil carbon decomposition in forest organic layer and mineral soil.

    PubMed

    Xu, Wenhua; Li, Wei; Jiang, Ping; Wang, Hui; Bai, Edith

    2014-10-01

    The roles of substrate availability and quality in determining temperature sensitivity (Q10) of soil carbon (C) decomposition are still unclear, which limits our ability to predict how soil C storage and cycling would respond to climate change. Here we determined Q10 in surface organic layer and subsurface mineral soil along an elevation gradient in a temperate forest ecosystem. Q10 was calculated by comparing the times required to respire a given amount of soil C at 15 and 25°C in a 350-day incubation. Results indicated that Q10 of the organic layer was 0.22-0.71 (absolute difference) higher than Q10 of the mineral soil. Q10 in both the organic layer (2.5-3.4) and the mineral soil (2.1-2.8) increased with decreasing substrate quality during the incubation. This enhancement of Q10 over incubation time in both layers suggested that Q10 of more labile C was lower than that of more recalcitrant C, consistent with the Arrhenius kinetics. No clear trend of Q10 was found along the elevation gradient. Because the soil organic C pool of the organic layer in temperate forests is large, its higher temperature sensitivity highlights its importance in C cycling under global warming.

  13. Effect of potassium salts and distillery effluent on carbon mineralization in soil.

    PubMed

    Chandra, Suresh; Joshi, H C; Pathak, H; Jain, M C; Kalra, N

    2002-07-01

    Distillery effluent, a rich source of potassium, is used for irrigation at many places in the world. A laboratory experiment was conducted to study the influence of potassium salts present in post-methanation distillery effluent (PME) along with two other salts, KCl and K2SO4, on mineralization of carbon in soil. PME oxidized with H2O2, raw PME, KCl and K2SO4 solutions containing K equivalent to 10%, 20%, 40% and 100% of K present in PME were added to the soil separately, maintaining four replications for each treatment and control. Addition of salts up to a certain concentration stimulated C mineralization but a decline was noticed at higher concentrations. All the levels of salts caused higher CO2 evolution than the control suggesting that the presence of K salts enhanced the microbial activity resulting in increased CO2 evolution. The influence of K2SO4 was significantly higher than KCl in stimulating C mineralization in soil. Oxidized effluent had a higher stimulating effect than inorganic salts, showing the influence of other salts accompanying K in the PME. Raw PME, which contained excess organic C, increased CO2 evolution even at the highest salt level (100% PME) signifying the effect of added C on alleviating the salt stress on microbial activity. PMID:12094803

  14. Differential controls on soil carbon density and mineralization among contrasting forest types in a temperate forest ecosystem.

    PubMed

    You, Ye-Ming; Wang, Juan; Sun, Xiao-Lu; Tang, Zuo-Xin; Zhou, Zhi-Yong; Sun, Osbert Jianxin

    2016-03-01

    Understanding the controls on soil carbon dynamics is crucial for modeling responses of ecosystem carbon balance to global change, yet few studies provide explicit knowledge on the direct and indirect effects of forest stands on soil carbon via microbial processes. We investigated tree species, soil, and site factors in relation to soil carbon density and mineralization in a temperate forest of central China. We found that soil microbial biomass and community structure, extracellular enzyme activities, and most of the site factors studied varied significantly across contrasting forest types, and that the associations between activities of soil extracellular enzymes and microbial community structure appeared to be weak and inconsistent across forest types, implicating complex mechanisms in the microbial regulation of soil carbon metabolism in relation to tree species. Overall, variations in soil carbon density and mineralization are predominantly accounted for by shared effects of tree species, soil, microclimate, and microbial traits rather than the individual effects of the four categories of factors. Our findings point to differential controls on soil carbon density and mineralization among contrasting forest types and highlight the challenge to incorporate microbial processes for constraining soil carbon dynamics in global carbon cycle models.

  15. Differential controls on soil carbon density and mineralization among contrasting forest types in a temperate forest ecosystem

    NASA Astrophysics Data System (ADS)

    You, Ye-Ming; Wang, Juan; Sun, Xiao-Lu; Tang, Zuo-Xin; Zhou, Zhi-Yong; Sun, Osbert Jianxin

    2016-03-01

    Understanding the controls on soil carbon dynamics is crucial for modeling responses of ecosystem carbon balance to global change, yet few studies provide explicit knowledge on the direct and indirect effects of forest stands on soil carbon via microbial processes. We investigated tree species, soil, and site factors in relation to soil carbon density and mineralization in a temperate forest of central China. We found that soil microbial biomass and community structure, extracellular enzyme activities, and most of the site factors studied varied significantly across contrasting forest types, and that the associations between activities of soil extracellular enzymes and microbial community structure appeared to be weak and inconsistent across forest types, implicating complex mechanisms in the microbial regulation of soil carbon metabolism in relation to tree species. Overall, variations in soil carbon density and mineralization are predominantly accounted for by shared effects of tree species, soil, microclimate, and microbial traits rather than the individual effects of the four categories of factors. Our findings point to differential controls on soil carbon density and mineralization among contrasting forest types and highlight the challenge to incorporate microbial processes for constraining soil carbon dynamics in global carbon cycle models.

  16. Differential controls on soil carbon density and mineralization among contrasting forest types in a temperate forest ecosystem

    PubMed Central

    You, Ye-Ming; Wang, Juan; Sun, Xiao-Lu; Tang, Zuo-Xin; Zhou, Zhi-Yong; Sun, Osbert Jianxin

    2016-01-01

    Understanding the controls on soil carbon dynamics is crucial for modeling responses of ecosystem carbon balance to global change, yet few studies provide explicit knowledge on the direct and indirect effects of forest stands on soil carbon via microbial processes. We investigated tree species, soil, and site factors in relation to soil carbon density and mineralization in a temperate forest of central China. We found that soil microbial biomass and community structure, extracellular enzyme activities, and most of the site factors studied varied significantly across contrasting forest types, and that the associations between activities of soil extracellular enzymes and microbial community structure appeared to be weak and inconsistent across forest types, implicating complex mechanisms in the microbial regulation of soil carbon metabolism in relation to tree species. Overall, variations in soil carbon density and mineralization are predominantly accounted for by shared effects of tree species, soil, microclimate, and microbial traits rather than the individual effects of the four categories of factors. Our findings point to differential controls on soil carbon density and mineralization among contrasting forest types and highlight the challenge to incorporate microbial processes for constraining soil carbon dynamics in global carbon cycle models. PMID:26925871

  17. Oxic and anoxic mineralization of simple carbon substrates in peat at low temperatures

    NASA Astrophysics Data System (ADS)

    Segura, Javier; Sparrman, Tobias; Nilsson, Mats; Schleucher, Jürgen; Öquist, Mats

    2016-04-01

    Northern peatlands store approximately one-quarter of the world's soil carbon and typically act as net carbon sinks. However a large fraction of the carbon fixed during the growing season can be emitted back to the atmosphere during winter as CO2 and CH4, despite low temperatures and frozen conditions, making low temperature biogeochemical processes crucial for the long-term net ecosystem carbon balance. However, the metabolic processes driving carbon mineralization under winter conditions are poorly understood and whether or not peat microbial communities can maintain metabolic activity at temperatures below freezing is uncertain. Here we present results from an incubation study aimed at elucidating the potential of peat microbial communities to mineralize simple carbon substrates to CO2 and CH4 at low temperatures. Peat samples from the acrotelm were amended with [13C]- glucose and incubated at -5 °C, -3 °C, +4 °C, and +9 °C under both oxic and anoxic conditions, and rates of CO2 and CH4 production were determined. In addition, incorporation of the labelled substrate into phospholipid fatty acids (PLFAs) were determined to account for microbial growth during mineralization and the metabolic partitioning between catabolic and anabolic activity. Biogenic [13C]-CO2 was produced from the added substrate in peat samples incubated both under oxic and anoxic conditions. Under oxic conditions the production rates were 3.5, 2.3, 0.3 and 0.07 mg CO2 g SOM-1day-1 at +9 °C, +4 °C, -3 °C and -5 °C, respectively, and corresponding rates for anoxic conditions were 1.1, 1.0, 0.03 and 0.01 mg CO2 g SOM-1day-1. Consequently the observed Q10 values of the temperature sensitivity under both oxic and anoxic conditions increased dramatically upon soil freezing. However, anoxic mineralization appears less sensitive to temperature as compared to when oxygen is present. Methane was also produced and detected across the range of the incubation temperatures in the anoxic

  18. Oxic and anoxic mineralization of simple carbon substrates in peat at low temperatures

    NASA Astrophysics Data System (ADS)

    Segura, Javier; Sparrman, Tobias; Nilsson, Mats; Schleucher, Jürgen; Öquist, Mats

    2016-04-01

    Northern peatlands store approximately one-quarter of the world's soil carbon and typically act as net carbon sinks. However a large fraction of the carbon fixed during the growing season can be emitted back to the atmosphere during winter as CO2 and CH4, despite low temperatures and frozen conditions, making low temperature biogeochemical processes crucial for the long-term net ecosystem carbon balance. However, the metabolic processes driving carbon mineralization under winter conditions are poorly understood and whether or not peat microbial communities can maintain metabolic activity at temperatures below freezing is uncertain. Here we present results from an incubation study aimed at elucidating the potential of peat microbial communities to mineralize simple carbon substrates to CO2 and CH4 at low temperatures. Peat samples from the acrotelm were amended with [13C]- glucose and incubated at -5 °C, -3 °C, +4 °C, and +9 °C under both oxic and anoxic conditions, and rates of CO2 and CH4 production were determined. In addition, incorporation of the labelled substrate into phospholipid fatty acids (PLFAs) were determined to account for microbial growth during mineralization and the metabolic partitioning between catabolic and anabolic activity. Biogenic [13C]-CO2 was produced from the added substrate in peat samples incubated both under oxic and anoxic conditions. Under oxic conditions the production rates were 3.5, 2.3, 0.3 and 0.07 mg CO2 g SOM‑1day‑1 at +9 °C, +4 °C, -3 °C and -5 °C, respectively, and corresponding rates for anoxic conditions were 1.1, 1.0, 0.03 and 0.01 mg CO2 g SOM‑1day‑1. Consequently the observed Q10 values of the temperature sensitivity under both oxic and anoxic conditions increased dramatically upon soil freezing. However, anoxic mineralization appears less sensitive to temperature as compared to when oxygen is present. Methane was also produced and detected across the range of the incubation temperatures in the anoxic

  19. Mineral Control of Soil Carbon Dynamics in Forest Soils: A Lithosequence Under Ponderosa Pine

    NASA Astrophysics Data System (ADS)

    Heckman, K. A.; Welty-Bernard, A.; Rasmussen, C.; Schwartz, E.; Chorover, J.

    2008-12-01

    The role of soil organic carbon in regulating atmospheric CO2 concentration has spurred interest in both quantifying existing soil C stocks and modeling the behavior of soil C under climate change scenarios. Soil parent material exerts direct control over soil organic carbon content through its influence on soil pH and mineral composition. Soil acidity and mineral composition also influence soil microbial community composition and activity, thereby controlling soil respiration rates and microbial biomass size. We sampled a lithosequence of four parent materials (rhyolite, granite, basalt, limestone) under Pinus ponderosa to examine the effects of soil mineralogy and acidity on soil organic carbon content and soil microbial community. Three soil profiles were examined on each parent material and analyzed by X-ray diffraction, pH, selective dissolution, C and N content, and 13C signature. Soils from each of the four parent materials were incubated for 40 days, and microbial communities were compared on the basis of community composition (as determined through T-RFLP analysis), specific metabolic activity, biomass, δ13C of respired CO2, and cumulative amount of C mineralized over the course of the incubation. Soil C content varied significantly among soils of different parent material, and was strongly and positively associated with the abundance of Al-humus complexes r2 = 0.71; P < 0.0001, Fe-humus complexes r2 = 0.74; P = 0.0003, and crystalline Fe-oxide content r2 = 0.63; P = 0.0023. Microbial community composition varied significantly among soils and showed strong associations with soil pH 1:1 in KCl; r2 = 0.87; P < 0.0001, concentration of exchangeable Al r2 = 0.81; P < 0.0001, amorphous Fe oxide content r2 = 0.59; P < 0.004, and Al-humus content r2 = 0.35; P < 0.04. Mineralization rates, biomass and δ13C of respired CO2 differed among parent materials, and also varied with incubation time as substrate quality and N availability changed. The results demonstrate

  20. Carbon dioxide exchange of a perennial bioenergy crop cultivation on a mineral soil

    NASA Astrophysics Data System (ADS)

    Lind, S. E.; Shurpali, N. J.; Peltola, O.; Mammarella, I.; Hyvönen, N.; Maljanen, M.; Räty, M.; Virkajärvi, P.; Martikainen, P. J.

    2015-10-01

    One of the strategies to reduce carbon dioxide (CO2) emissions from the energy sector is to increase the use of renewable energy sources such as bioenergy crops. Bioenergy is not necessarily carbon neutral because of greenhouse gas (GHG) emissions during biomass production, field management and transportation. The present study focuses on the cultivation of reed canary grass (RCG, Phalaris arundinaceae L.), a perennial bioenergy crop, on a mineral soil. To quantify the CO2 exchange of this RCG cultivation system, and to understand the key factors controlling its CO2 exchange, the net ecosystem CO2 exchange (NEE) was measured during three years using the eddy covariance (EC) method. The RCG cultivation thrived well producing yields of 6200 and 6700 kg DW ha-1 in 2010 and 2011, respectively. Gross photosynthesis (GPP) was controlled mainly by radiation from June to September. Vapour pressure deficit (VPD), air temperature or soil moisture did not limit photosynthesis during the growing season. Total ecosystem respiration (TER) increased with soil temperature, green area index and GPP. Annual NEE was -262 and -256 g C m-2 in 2010 and 2011, respectively. Throughout the studied period, cumulative NEE was -575 g C m-2. When compared to the published data for RCG on an organic soil, the cultivation of this crop on a mineral soil had higher capacity to take up CO2 from the atmosphere.

  1. Factors driving carbon mineralization priming effect in a soil amended with different types of biochar

    NASA Astrophysics Data System (ADS)

    Cely, P.; Tarquis, A. M.; Paz-Ferreiro, J.; Méndez, A.; Gascó, G.

    2014-03-01

    The effect of biochar on soil carbon mineralization priming effect depends on the characteristics of the raw materials, production method and pyrolysis conditions. The goal of the present study is to evaluate the impact of three different types of biochar on soil CO2 emissions and in different physicochemical properties. For this purpose, a sandy-loam soil was amended with the three biochars (BI, BII and BIII) at a rate of 8 wt % and soil CO2 emissions were measured for 45 days. BI is produced from a mixed wood sieving's from wood chip production, BII from a mixture of paper sludge and wheat husks and BIII from sewage sludge. Cumulative CO2 emissions of biochars, soil and amended soil were well fit to a simple first-order kinetic model with correlation coefficients (r2) greater than 0.97. Results shown a negative priming effect in the soil after addition of BI and a positive priming effect in the case of soil amended with BII and BIII. These results can be related with different biochar properties such as ash content, volatile matter, fixed carbon, organic carbon oxidised with dichromate, soluble carbon and metal and phenolic substances content in addition to surface biochar properties. Three biochars increased the values of soil field capacity and wilting point, while effects over pH and cation exchange capacity were not observed.

  2. Organic carbon redistribution due to erosion at various spatial scales

    NASA Astrophysics Data System (ADS)

    Jakab, Gergely; Szabó, Judit; Szalai, Zoltán; Mészáros, Erzsébet; Szabó, Boglárka; Centeri, Csaba

    2016-04-01

    Soil organic carbon (SOC) has a crucial role both in terms of crop production and climate change mitigation. Soil could be an effective sink of atmospheric carbon since in agricultural areas the carbon content of the soil is much lower than its capacity. The main obstacle against carbon charge of the soils is cultivation and erosion. Soil detachment, delivery and deposition are rather scale dependent processes that is why it is difficult to compare or extrapolate results among scales. Present case study aims to compare the SOC content and soil organic matter (SOM) compound of the detached soil particles on the ridge to those that are deposited at the bottom of the catena in order to clarify the role of delivery in soil erosion. Initial soil erosion was modelled using a laboratory rainfall simulator at the point scale. Deposition was surveyed and analysed by 3D sampling from drillings on the sedimentary parts at the field scale. At the detachment phase carbon enrichment (50-100%) and C/N ratio increase were found in each aggregate size class of the detached soil particles. Variations in SOM compounds suggested that a very intensive SOM exchange took place during initial erosion processes and delivery. In addition to the selective erosion selective SOC deposition were also found at the field scale. Two topographical hotspots were identified as the place of SOC surplus deposition. In these patches SOM compounds were deposited separately due to different geomorphologic positions. The lower patch next to the end of an ephemeral gully was dominated by less polymerized more aromatic SOM, while the upper one was ruled by high molecular weighted aliphatic SOM. Difference in SOM compound was manifested also in different sediment morphology. The topographically higher deposition patch were covered by aggregates while the lower one was found to be sealed by individual soil particles. Present study was supported by the National Hungarian Research Found K100180, G. Jakab was

  3. Mineralogical control of soil organic carbon persistence at the multidecadal time scale

    NASA Astrophysics Data System (ADS)

    Lutfalla, Suzanne; Barré, Pierre; Bernard, Sylvain; Le Guillou, Corentin; Chenu, Claire

    2015-04-01

    One of the current challenges in understanding the long term persistence of organic carbon in soils is to assess how mineral surfaces, especially at small scale, can stabilize soil organic carbon (SOC). The question we address in this work is whether different mineral species stabilize different types of SOC. Here we used the unique opportunity offered by long term bare fallows to study in situ C dynamics in several fine fractions of a silty loam soil. Indeed, with no vegetation i.e. no external input of fresh C, the plant-free soil of the Versailles 42 Plots (INRA, France) has been progressively enriched in persistent SOC during the 80 years of bare fallow. To separate mineral phases of the clay size fraction we performed a size fractionation on samples taken from 4 different plots at 5 different dates (0, 10, 22, 52, and 79 years after the beginning of the BF) and analyzed the SOC in the different fractions thus obtained. First, the clay fraction (< 2 µm) was isolated by wet sieving and centrifugation in water. Then, the clay fraction was further separated into 3 size fractions by centrifugation: fine clay (< 0.05 µm), intermediate clay (0.05 - 0.2 µm), and coarse clay (0.2 - 2 µm). X-ray diffraction was used to determine the mineralogy of the phases and we found that the coarse clay fraction on the one hand and fine and intermediate clay fractions on the other hand exhibited contrasted mineralogies. Fine and intermediate clay fractions contained almost exclusively smectite and mixed-layered illite/smectite minerals whereas coarse clays contained also discrete illite and kaolinite on top of smectite and illite/smectite. We carried out CHN elemental analysis to study the C and nitrogen dynamics with time in the different fractions. And synchrotron based spectroscopy and microscopy (NEXAFS bulk and STXM at the carbon K edge of 280 eV, CLS Saskatoon, Canada) was used to get information on the distribution and the chemical speciation of the SOC in fractions with

  4. Ground cover rice production system facilitates soil carbon and nitrogen stocks at regional scale

    NASA Astrophysics Data System (ADS)

    Liu, M.; Dannenmann, M.; Lin, S.; Saiz, G.; Yan, G.; Yao, Z.; Pelster, D.; Tao, H.; Sippel, S.; Tao, Y.; Zhang, Y.; Zheng, X.; Zuo, Q.; Butterbach-Bahl, K.

    2015-02-01

    Rice production is increasingly challenged by irrigation water scarcity, however covering paddy rice soils with films (ground cover rice production system: GCRPS) can significantly reduce water demand as well as overcome temperature limitations at the beginning of the vegetation period resulting in increased grain yields in colder regions of rice production with seasonal water shortages. It has been speculated that the increased soil aeration and temperature under GCRPS may result in losses of soil organic carbon and nitrogen stocks. Here we report on a regional scale experiment, conducted by sampling paired adjacent Paddy and GCRPS fields at 49 representative sites in the Shiyan region, which is typical for many mountainous areas across China. Parameters evaluated included soil C and N stocks, soil physical and chemical properties, potential carbon mineralization rates, fractions of soil organic carbon and stable carbon isotopic composition of plant leaves. Furthermore, root biomass was quantified at maximum tillering stage at one of our paired sites. Against expectations the study showed that: (1) GCRPS significantly increased soil organic C and N stocks 5-20 years following conversion of production systems, (2) there were no differences between GCRPS and Paddy in soil physical and chemical properties for the various soil depths with the exception of soil bulk density, (3) GCRPS had lower mineralization potential for soil organic C compared with Paddy over the incubation period, (4) GCRPS showed lower δ15N in the soils and plant leafs indicating less NH3 volatilization in GCRPS than in Paddy; and (5) GCRPS increased yields and root biomass in all soil layers down to 40 cm depth. Our results suggest that GCRPS is an innovative rice production technique that not only increases yields using less irrigation water, but that it also is environmentally beneficial due to increased soil C and N stocks at regional scale.

  5. A Numerical Study on Combining CO2 Mineral Carbonation and Geothermal Energy Development

    NASA Astrophysics Data System (ADS)

    Wan, Y.; Xu, T.; Pruess, K.

    2010-12-01

    There is growing interest in the novel concept of operating Enhanced Geothermal Systems (EGS) with CO2 instead of water as heat transmission fluid. Initial studies have suggested that CO2 may achieve larger rates of heat extraction, and can offer geologic storage of carbon as an ancillary benefit. A fully developed EGS with CO2 would consist of three distinct zones, (1) a central zone or “core” in which all aqueous phase has been removed by dissolution into the flowing CO2 stream, so that the reservoir fluid is a single supercritical CO2 phase; (2) a surrounding intermediate zone, in which the reservoir fluid consists of a two-phase water-CO2 mixture; and (3) an outer or peripheral zone, in which the reservoir fluid is a single aqueous phase with dissolved CO2. Fluid-rock interactions in EGS operated with CO2 are expected to be vastly different in zones with an aqueous phase present, as compared to the central reservoir zone with anhydrous supercritical CO2. We have performed chemically reactive transport (TOUGHREACT ) modeling to investigate fluid-rock interactions and CO2 mineral carbonation of an EGS operated with CO2. The quartz monzodiorite unit at the Enhanced Geothermal Systems (EGS) site at Desert Peak (Nevada) was taken as an example. A geothermal injection well system with supercritical CO2 injection was simulated to (1) investigate mineral dissolution/precipitation and associated porosity changes, and (2) impacts on reservoir growth and longevity, with ramifications for sustaining energy recovery, for estimating CO2 loss rates, and for figuring tradeoffs between power generation and CO2 mineralization (geologic storage).

  6. Influence of substrate mineralogy on bacterial mineralization of calcium carbonate: implications for stone conservation.

    PubMed

    Rodriguez-Navarro, Carlos; Jroundi, Fadwa; Schiro, Mara; Ruiz-Agudo, Encarnación; González-Muñoz, María Teresa

    2012-06-01

    The influence of mineral substrate composition and structure on bacterial calcium carbonate productivity and polymorph selection was studied. Bacterial calcium carbonate precipitation occurred on calcitic (Iceland spar single crystals, marble, and porous limestone) and silicate (glass coverslips, porous sintered glass, and quartz sandstone) substrates following culturing in liquid medium (M-3P) inoculated with different types of bacteria (Myxococcus xanthus, Brevundimonas diminuta, and a carbonatogenic bacterial community isolated from porous calcarenite stone in a historical building) and direct application of sterile M-3P medium to limestone and sandstone with their own bacterial communities. Field emission scanning electron microscopy (FESEM), atomic force microscopy (AFM), powder X-ray diffraction (XRD), and 2-dimensional XRD (2D-XRD) analyses revealed that abundant highly oriented calcite crystals formed homoepitaxially on the calcitic substrates, irrespective of the bacterial type. Conversely, scattered spheroidal vaterite entombing bacterial cells formed on the silicate substrates. These results show that carbonate phase selection is not strain specific and that under equal culture conditions, the substrate type is the overruling factor for calcium carbonate polymorph selection. Furthermore, carbonate productivity is strongly dependent on the mineralogy of the substrate. Calcitic substrates offer a higher affinity for bacterial attachment than silicate substrates, thereby fostering bacterial growth and metabolic activity, resulting in higher production of calcium carbonate cement. Bacterial calcite grows coherently over the calcitic substrate and is therefore more chemically and mechanically stable than metastable vaterite, which formed incoherently on the silicate substrates. The implications of these results for technological applications of bacterial carbonatogenesis, including building stone conservation, are discussed.

  7. Influence of substrate mineralogy on bacterial mineralization of calcium carbonate: implications for stone conservation.

    PubMed

    Rodriguez-Navarro, Carlos; Jroundi, Fadwa; Schiro, Mara; Ruiz-Agudo, Encarnación; González-Muñoz, María Teresa

    2012-06-01

    The influence of mineral substrate composition and structure on bacterial calcium carbonate productivity and polymorph selection was studied. Bacterial calcium carbonate precipitation occurred on calcitic (Iceland spar single crystals, marble, and porous limestone) and silicate (glass coverslips, porous sintered glass, and quartz sandstone) substrates following culturing in liquid medium (M-3P) inoculated with different types of bacteria (Myxococcus xanthus, Brevundimonas diminuta, and a carbonatogenic bacterial community isolated from porous calcarenite stone in a historical building) and direct application of sterile M-3P medium to limestone and sandstone with their own bacterial communities. Field emission scanning electron microscopy (FESEM), atomic force microscopy (AFM), powder X-ray diffraction (XRD), and 2-dimensional XRD (2D-XRD) analyses revealed that abundant highly oriented calcite crystals formed homoepitaxially on the calcitic substrates, irrespective of the bacterial type. Conversely, scattered spheroidal vaterite entombing bacterial cells formed on the silicate substrates. These results show that carbonate phase selection is not strain specific and that under equal culture conditions, the substrate type is the overruling factor for calcium carbonate polymorph selection. Furthermore, carbonate productivity is strongly dependent on the mineralogy of the substrate. Calcitic substrates offer a higher affinity for bacterial attachment than silicate substrates, thereby fostering bacterial growth and metabolic activity, resulting in higher production of calcium carbonate cement. Bacterial calcite grows coherently over the calcitic substrate and is therefore more chemically and mechanically stable than metastable vaterite, which formed incoherently on the silicate substrates. The implications of these results for technological applications of bacterial carbonatogenesis, including building stone conservation, are discussed. PMID:22447589

  8. Influence of Substrate Mineralogy on Bacterial Mineralization of Calcium Carbonate: Implications for Stone Conservation

    PubMed Central

    Jroundi, Fadwa; Schiro, Mara; Ruiz-Agudo, Encarnación; González-Muñoz, María Teresa

    2012-01-01

    The influence of mineral substrate composition and structure on bacterial calcium carbonate productivity and polymorph selection was studied. Bacterial calcium carbonate precipitation occurred on calcitic (Iceland spar single crystals, marble, and porous limestone) and silicate (glass coverslips, porous sintered glass, and quartz sandstone) substrates following culturing in liquid medium (M-3P) inoculated with different types of bacteria (Myxococcus xanthus, Brevundimonas diminuta, and a carbonatogenic bacterial community isolated from porous calcarenite stone in a historical building) and direct application of sterile M-3P medium to limestone and sandstone with their own bacterial communities. Field emission scanning electron microscopy (FESEM), atomic force microscopy (AFM), powder X-ray diffraction (XRD), and 2-dimensional XRD (2D-XRD) analyses revealed that abundant highly oriented calcite crystals formed homoepitaxially on the calcitic substrates, irrespective of the bacterial type. Conversely, scattered spheroidal vaterite entombing bacterial cells formed on the silicate substrates. These results show that carbonate phase selection is not strain specific and that under equal culture conditions, the substrate type is the overruling factor for calcium carbonate polymorph selection. Furthermore, carbonate productivity is strongly dependent on the mineralogy of the substrate. Calcitic substrates offer a higher affinity for bacterial attachment than silicate substrates, thereby fostering bacterial growth and metabolic activity, resulting in higher production of calcium carbonate cement. Bacterial calcite grows coherently over the calcitic substrate and is therefore more chemically and mechanically stable than metastable vaterite, which formed incoherently on the silicate substrates. The implications of these results for technological applications of bacterial carbonatogenesis, including building stone conservation, are discussed. PMID:22447589

  9. Isotopic Fractionation of Mg2+(aq), Ca2+(aq), and Fe2+(aq) with Carbonate Minerals

    SciTech Connect

    Rustad, James R.; Casey, William H.; Yin, Qing-Zhu; Bylaska, Eric J.; Felmy, Andrew R.; Bogatko, Stuart A.; Jackson, Virgil E.; Dixon, David A.

    2010-11-15

    Density functional electronic structure calculations are used to compute the equilibrium constant (the isotope fractionation factor) for 26Mg/24Mg and 44Ca/40Ca isotope exchange between carbonate minerals and uncomplexed divalent aquo ions. The most reliable calculations at the B3LYP/6-311++G(2d,2p) level predict equilibrium constants K, reported as 103ln(K) at 25 °C, of -5.3, -1.1, and +1.1 for 26Mg/24Mg exchange between calcite (CaCO3), magnesite (MgCO3), and dolomite (Ca0.5Mg0.5CO3), respectively, and Mg2+(aq), with positive values indicating enrichment in the mineral phase. For 44Ca/40Ca exchange between calcite and Ca2+(aq), the calculations predict values of +1.5 for Ca2+(aq) in six-fold coordination and +4.1 for Ca2+(aq) in seven-fold coordination. We find that the reduced partition function ratios can be reliably computed from systems as small as M(CO3)610- and M2+(H2O)6 embedded in a set of fixed atoms representing the 2nd shell (and greater) coordination environment. We find that the aqueous cluster representing the aquo ion is much more sensitive to improvements in the basis set than the calculations on the mineral systems, and that fractionation factors should be computed using 2 the best possible basis set for the aquo complex, even if the reduced partition function ratio calculated with the same basis set is not available for the mineral system. The new calculations show that the previous discrepancies between theory and experiment for Fe3+-hematite and Fe2+-siderite fractionations arise from an insufficiently accurate reduced partition function ratio for the Fe3+(aq) and Fe2+(aq) species.

  10. Carbon delivery to deep mineral horizons in Hawaiian rain forest soils

    NASA Astrophysics Data System (ADS)

    Marin-Spiotta, Erika; Chadwick, Oliver A.; Kramer, Marc; Carbone, Mariah S.

    2011-09-01

    This study aimed to better understand the mechanisms for soil organic matter delivery to and accumulation in mineral horizons of tropical rain forest, volcanic soils. We used soil morphology, lysimetry, isotopes, and spectroscopy to investigate the role of preferential flow paths in the delivery of carbon (C) to the subsoil. High rainfall, high primary productivity, and the dominance of highly reactive, short-range-order minerals combine to sequester substantial stocks of soil C with long mean residence times. The soils have large peds, separated by wide cracks, which form a network of channels propagating downward through the top 40 to 60 cm, facilitating macropore flow. The channel infillings and crack surfaces were enriched in organic material (OM) with lower C:N ratios, and had higher ammonium oxalate-extractable Al, and lower ammonium oxalate-extractable Fe than the adjacent mineral bulk soil. CP MAS 13C-NMR spectra of OM accumulating at depth showed strong signal intensities in the carboxyl and carbonyl C regions, indicative of organic acids, while decaying roots showed greater contributions of aromatic and O-alkyl C. The ratios of alkyl-to-O-alkyl C in the organic infillings were more similar to those of the bulk Bh and to dissolved organic matter than to those of decaying roots. Radiocarbon-based ages of OM infillings at >50 cm depth were significantly younger than the mineral soil (2000 years versus 7000 years). Respired CO2 from incubated soils showed that OM accumulating at depth is a mixture of modern and much older C, providing further evidence for the downward movement of fresh C.

  11. Carbon and nitrogen pools and mineralization rates in boreal forest soil after stump harvesting

    NASA Astrophysics Data System (ADS)

    Kaarakka, Lilli; Hyvönen, Riitta; Strömgren, Monika; Palviainen, Marjo; Persson, Tryggve; Olsson, Bengt A.; Helmisaari, Heljä-Sisko

    2016-04-01

    The use of forest-derived biomass has steadily increased in the Finland and Sweden during the past decades. Thus, more intensive forest management practices are becoming more common in the region, such as whole-tree harvesting, both above- and belowground. Stump harvesting causes a direct removal of carbon (C) in the form of biomass from the stand and can cause extensive soil disturbance, which in turn can result in increased C mineralization. In this study, the effects of stump harvesting on soil C and nitrogen (N) mineralization, and soil surface disturbance were studied at two different clear-felled Norway spruce (Picea abies) stands in Central Finland. The treatments were conventional stem-only harvesting combined with mounding (WTH) and stump harvesting (i.e. complete tree harvesting) combined with mounding (WTH+S). Logging residues were removed from all study sites. Soil samples down to a depth of 20 cm were systematically collected from the different soil disturbance surfaces (undisturbed soil, the mounds and the pits) 12-13 years after final harvest. Soil samples were incubated in the laboratory to determine the C and N mineralization rates. In addition, total C and N pools were estimated for each disturbance class and soil layer. Soil C and N pools were lower following stump harvesting, however, no statistically significant treatment effect was detected. Instead, C mineralization responses to treatment intensity was site-specific. C/N-ratio and organic matter content were significantly affected by harvest intensity. The observed changes in C and N pools appear to be related to the intrinsic variation of the surface disturbance and soil characteristics, and harvesting per se, rather than treatment intensity. Long-term studies are however needed to draw long-term conclusions whether stump harvesting significantly changes soil C and nutrient dynamics.

  12. Earthworm species influence on carbon-mineral association in a sugar maple forest in northern Minnesota

    NASA Astrophysics Data System (ADS)

    Lyttle, A.; Yoo, K.; Aufdenkampe, A. K.; Hale, C. M.; Sebestyen, S. D.

    2011-12-01

    Non-native European earthworms are invading previously earthworm-free hardwood forests in the northern Great Lakes Region. Whereas earthworms' impacts on soil morphology and geochemical properties have been well documented in agricultural settings, the role of earthworms in biogeochemical cycles of undisturbed forests remains poorly understood. The forest soils that were recently invaded by exotic earthworms, therefore, provide a unique opportunity to understand how and how much earthworms contribute to biogeochemistry of non-agricultural environments. Increased degree and extent of soil mixing is one of the better known consequences of the earthworm invasion. Our hypothesis is that invasive earthworms positively affect carbon (C) stabilization by enhancing contacts between organic matter and minerals. We are studying C-mineral complexation along a well-established earthworm chronosequence in a sugar maple forest in northern Minnesota. We have observed changes in total earthworm biomass, A horizon C storage, and total specific surface area (SSA) of minerals as the invasion progresses. Because each earthworm species has different feeding and dwelling habits, biogeochemical imprints of the invasion reflect not only earthworms' biomass but also their species composition. All earthworm species show an increase in their biomass with greater time length since the invasion, though epigeic earthworms tend to be the pioneer species. As the total earthworm biomass increases, we find greater incorporation of organic C into the A horizon; the O horizon thickness decreases from 8 to 0 cm as the A horizon thickens from ~5 cm to ~12 cm. While leaf litter biomass is negatively correlated with total earthworm biomass, dramatic decreases in litter biomass are coupled with considerable increases in the biomass of epi-endogeic species. Despite the general decrease in C storage in the A horizon with greater degree of invasion, the storages fluctuate along the transect because

  13. Carbonate minerals, oxygen and carbon isotopes in modern temperate bryozoa, eastern Tasmania, Australia

    NASA Astrophysics Data System (ADS)

    Prasada Rao, C.

    1993-12-01

    X-ray analysis of cool temperate bryozoa from eastern shelf carbonates indicates the occurrence of a spectrum of low-Mg calcite to high-Mg calcite with variable amounts of aragonite. Bryozoa contain variable amounts of CaCO 3 cements. In bryozoa δ18O values increase and δ13C values decrease with increasing aragonite content probably due to the occurrence of vaterite. Aragonite contents decrease with decreasing water temperatures as established by oxygen isotope thermometry. Tasmanian bryozoa may be enriched in δ18O up to 0.7‰ due to aragonite and high Mg-calcite contents. δ13C values of bryozoa composed of pure calcite are similar to those of associated brachiopods. δ18O and δ13C values of bryozoa are unaffected by kinetic and metabolic effects. The isotopic field of temperate bryozoa differs from tropical carbonates by having heavier δ18O ( 1.3‰ ± 0.5) and lighter δ13C ( 1.8‰ ± 0.8) values than bulk tropical carbonates. The bryozoa are in equilibrium with upwelling deep seawater and surface subantarctic water and therefore intersect seafloor diagenesis and upwelling water trend lines. Mol% MgCO 3 content ranges from 2 to 11 in calcite and corresponds to 5-14°C water temperatures. The δ18O values of bryozoa give a range of temperatures from 7° to 13°C, slightly less than the 4-15°C obtained from δ18O of Tasmanian brachiopods. This discrepancy is probably due to either minor biochemical fractionation or to bryozoa being in equilibrium with warmer waters.

  14. Basalt-CO2-H2O Interactions and Variability in Carbonate Mineralization Rates

    SciTech Connect

    Schaef, Herbert T.; McGrail, B. Peter; Owen, Antionette T.

    2009-02-01

    Flood basalts are receiving increasing attention as possible host formations for geologic sequestration of anthropogenic CO2, with studies underway in the U.S., India, Iceland, and Canada. Our previous laboratory studies with Columbia River basalts showed relative quick precipitation of carbonate minerals compared to other siliclastic rocks when batch reacted with water and supercritical CO2. In this study, our prior work with Columbia River basalt was extended to tests with basalts from the eastern U.S., India, and Africa. The basalts are all similar in bulk chemistry and share common minerals such as plagioclase, augite, and a glassy mesostasis. Single pass flow through dissolution experiments under dilute solution and mildly acidic conditions indicate similar cation release behavior among the basalt samples tested. Despite similar bulk chemistry and apparent dissolution kinetics, long-term static experiments with CO2 saturated water show significant differences in rates of mineralization as well as precipitate chemistry and morphology. For example, basalt from the Newark Basin in the U.S. is by far the most reactive of any basalt tested to date. Carbonate reaction products for the Newark Basin basalt were globular in form and contained significantly more Fe than the secondary carbonates that precipitated on the other basalt samples. Calcite grains with classic “dogtooth spar” morphology and trace cation substitution (Mg and Mn) were observed in post-reacted samples associated with the Columbia River basalts. Other basalts produced solid precipitates with compositions that varied chemically throughout the entire testing period. Polished cross sections of the reacted grains show precipitate overgrowths with irregular regions outlined by dark and bright layers indicative of zonations of different compositions. For example, SEM-EDX analysis across carbonate precipitates, which resulted from 854 days of reaction of the Central Atlantic Mafic Province (CAMP

  15. Diffusion of helium in carbonates: Effects of mineral structure and composition

    NASA Astrophysics Data System (ADS)

    Cherniak, D. J.; Amidon, W.; Hobbs, D.; Watson, E. B.

    2015-09-01

    Diffusion of helium has been characterized in four carbonates: calcite, dolomite, magnesite, and aragonite. Cleaved or oriented and polished slabs of carbonate minerals were implanted with 100 keV or 3 MeV 3He at doses of 5 × 10153He/cm2 and 1 × 10163He/cm2, respectively, and annealed in 1-atm furnaces. 3He distributions following diffusion experiments were measured with nuclear reaction analysis using the reaction 3He(d,p)4He. Our results show that He diffusion in calcite is the fastest among the carbonates studied, with diffusivities progressively slower in magnesite, dolomite and aragonite. In the case of the isomorphic trigonal carbonates (calcite, dolomite, magnesite), these observations are broadly consistent with predictions based on lattice characteristics such as unit cell size and inter-atomic apertures, with diffusivities faster in more open carbonate structures. Dolomite is an exception to this trend, suggesting that its unique ordered R3 crystal structure may play a role in slowing helium diffusion. Diffusion is anisotropic in all of the trigonal carbonates, and is typically slowest for diffusion along the c direction, and faster for diffusion normal to c and in directions normal to cleavage surfaces. The patterns of diffusional anisotropy are predicted to first order by the size of limiting inter-atomic apertures along any given crystallographic direction, providing additional support to the concept of modeling crystal lattices as "molecular sieves" with regard to diffusion of helium. When the effects of anisotropy and diffusion domain size are considered, our results are in reasonable agreement with previous results from bulk degassing of natural samples. Modeling of helium diffusive loss shows that calcite and magnesite are unlikely to be retentive of helium on the Earth's surface for typical grain sizes and time/temperature conditions. Dolomite and aragonite may be retentive under cooler conditions, but because helium retention is strongly

  16. Early Implementation of Large Scale Carbon Dioxide Removal Projects through the Cement Industry

    NASA Astrophysics Data System (ADS)

    Zeman, F. S.

    2014-12-01

    The development of large-scale carbon dioxide reduction projects requires high purity CO2and a reactive cation source. A project seeking to provide both of these requirements will likely face cost barriers with current carbon prices. The cement industry is a suitable early implementation site for such projects by virtue of the properties of its exhaust gases and those of waste concrete. Cement plants are the second largest source of industrial CO2 emissions, globally. It is also the second largest commodity after water, has no ready substitute and is literally the foundation of society. Finally, half of the CO2 emissions originate from process reactions rather than fossil fuel combustion resulting in higher flue gas CO2concentrations. These properties, with the co-benefits of oxygen combustion, create a favorable environment for spatially suitable projects. Oxygen combustion involves substituting produced oxygen for air in a combustion reaction. The absence of gaseous N2 necessitates the recirculation of exhaust gases to maintain kiln temperatures, which increase the CO2 concentrations from 28% to 80% or more. Gas exit temperatures are also elevated (>300oC) and can reach higher temperatures if the multi stage pre-heater towers, that recover heat, are re-designed in light of FGR. A ready source of cations can be found in waste concrete, a by-product of construction and demolition activities. These wastes can be processed to remove cations and then reacted with atmospheric CO2 to produce carbonate minerals. While not carbon negative, they represent a demonstration opportunity for binding atmospheric CO2while producing a saleable product (precipitated calcium carbonate). This paper will present experimental results on PCC production from waste concrete along with modeling results for oxygen combustion at cement facilities. The results will be presented with a view to mineral sequestration process design and implementation.

  17. Mountaineer Commerical Scale Carbon Capture and Storage (CCS) Project

    SciTech Connect

    Deanna Gilliland; Matthew Usher

    2011-12-31

    The Final Technical documents all work performed during the award period on the Mountaineer Commercial Scale Carbon Capture & Storage project. This report presents the findings and conclusions produced as a consequence of this work. As identified in the Cooperative Agreement DE-FE0002673, AEP's objective of the Mountaineer Commercial Scale Carbon Capture and Storage (MT CCS II) project is to design, build and operate a commercial scale carbon capture and storage (CCS) system capable of treating a nominal 235 MWe slip stream of flue gas from the outlet duct of the Flue Gas Desulfurization (FGD) system at AEP's Mountaineer Power Plant (Mountaineer Plant), a 1300 MWe coal-fired generating station in New Haven, WV. The CCS system is designed to capture 90% of the CO{sub 2} from the incoming flue gas using the Alstom Chilled Ammonia Process (CAP) and compress, transport, inject and store 1.5 million tonnes per year of the captured CO{sub 2} in deep saline reservoirs. Specific Project Objectives include: (1) Achieve a minimum of 90% carbon capture efficiency during steady-state operations; (2) Demonstrate progress toward capture and storage at less than a 35% increase in cost of electricity (COE); (3) Store CO{sub 2} at a rate of 1.5 million tonnes per year in deep saline reservoirs; and (4) Demonstrate commercial technology readiness of the integrated CO{sub 2} capture and storage system.

  18. Carbonation of Clay Minerals Exposed to scCO2/Water at 200 degrees and 250 degrees C

    SciTech Connect

    Sugama, T.; Ecker, L.; Gill, S.; Butcher, T.; Bour, D.

    2010-11-01

    To clarify the mechanisms of carbonation of clay minerals, such as bentonite, kaolinite, and soft clay, we exposed them to supercritical carbon dioxide (scCO2)/water at temperatures of 200 and 250 C and pressures of 1500 and 2000 psi for 72- and 107-hours. Bentonite, comprising three crystalline phases, montmorillonite (MMT), anorthoclase-type albite, and quartz was susceptible to reactions with ionic carbonic acid yielded by the interactions between scCO2 and water, particularly MMT and anorthoclase-type albite phases. For MMT, the cation-exchangeable ions, such as Na+ and Ca2+, present in its basal interplanar space, were replaced by proton, H+, from ionic carbonic acid; thereafter, the cations leaching from MMT directly reacted with CO32- as a counter ion of H+ to form carbonate compounds. Such in-situ carbonation process in basal space caused the shrinkage and breakage of the spacing structure within MMT. In contrast, the wet carbonation of anorthoclase-type albite, categorized as rock minerals, entailed the formation of three amorphous by-products, such as carbonates, kaolinite-like compounds, and silicon dioxide. Together, these two different carbonations caused the disintegration and corruption of bentonite. Kaolinite clay containing the amorphous carbonates and silicon dioxide was inert to wet carbonation. We noted only a gain in weight due to its water uptake, suggesting that kaolinite-like by-products generated by the wet carbonation of rock minerals might remain unchanged even during extended exposure. Soft clay consisting of two crystalline phases, dolomite and silicon dioxide, also was unaltered by wet carbonation, despite the uptake of water.

  19. Carbonate minerals in porous media decrease mobility of polyacrylic acid modified zero-valent iron nanoparticles used for groundwater remediation.

    PubMed

    Laumann, Susanne; Micić, Vesna; Lowry, Gregory V; Hofmann, Thilo

    2013-08-01

    The limited transport of nanoscale zero-valent iron (nZVI) in porous media is a major obstacle to its widespread application for in situ groundwater remediation. Previous studies on nZVI transport have mainly been carried out in quartz porous media. The effect of carbonate minerals, which often predominate in aquifers, has not been evaluated to date. This study assessed the influence of the carbonate minerals in porous media on the transport of polyacrylic acid modified nZVI (PAA-nZVI). Increasing the proportion of carbonate sand in the porous media resulted in less transport of PAA-nZVI. Predicted travel distances were reduced to a few centimeters in pure carbonate sand compared to approximately 1.6 m in quartz sand. Transport modeling showed that the attachment efficiency and deposition rate coefficient increased linearly with increasing proportion of carbonate sand.

  20. Carbon dioxide exchange of a perennial bioenergy crop cultivation on a mineral soil

    NASA Astrophysics Data System (ADS)

    Lind, Saara E.; Shurpali, Narasinha J.; Peltola, Olli; Mammarella, Ivan; Hyvönen, Niina; Maljanen, Marja; Räty, Mari; Virkajärvi, Perttu; Martikainen, Pertti J.

    2016-03-01

    One of the strategies to reduce carbon dioxide (CO2) emissions from the energy sector is to increase the use of renewable energy sources such as bioenergy crops. Bioenergy is not necessarily carbon neutral because of greenhouse gas (GHG) emissions during biomass production, field management and transportation. The present study focuses on the cultivation of reed canary grass (RCG, Phalaris arundinacea L.), a perennial bioenergy crop, on a mineral soil. To quantify the CO2 exchange of this RCG cultivation system, and to understand the key factors controlling its CO2 exchange, the net ecosystem CO2 exchange (NEE) was measured from July 2009 until the end of 2011 using the eddy covariance (EC) method. The RCG cultivation thrived well producing yields of 6200 and 6700 kg DW ha-1 in 2010 and 2011, respectively. Gross photosynthesis (GPP) was controlled mainly by radiation from June to September. Vapour pressure deficit (VPD), air temperature or soil moisture did not limit photosynthesis during the growing season. Total ecosystem respiration (TER) increased with soil temperature, green area index and GPP. Annual NEE was -262 and -256 g C m-2 in 2010 and 2011, respectively. Throughout the study period from July 2009 until the end of 2011, cumulative NEE was -575 g C m-2. Carbon balance and its regulatory factors were compared to the published results of a comparison site on drained organic soil cultivated with RCG in the same climate. On this mineral soil site, the RCG had higher capacity to take up CO2 from the atmosphere than on the comparison site.

  1. Small-angle neutron scattering studies of mineralization on BSA coated citrate capped gold nanoparticles used as a model surface for membrane scaling in RO wastewater desalination.

    PubMed

    Dahdal, Y N; Pipich, V; Rapaport, H; Oren, Y; Kasher, R; Schwahn, D

    2014-12-23

    Bovine serum albumin (BSA) coated on citrate capped gold nanoparticles (BSA-GNPs) was exposed to a simulated wastewater effluent (SSE) in order to study the mineralization and thereby mimic scaling at biofouled membranes of reverse osmosis (RO) wastewater desalination plants. RO is a leading technology of achieving freshwater quality as it has the capability of removing both dissolved inorganic salts and organic contaminants from tertiary wastewater effluents. The aim was to better understand one of the major problems facing this technology which is fouling of the membranes, mainly biofouling and scaling by calcium phosphate. The experiments were performed using the small-angle neutron scattering (SANS) technique. The nanoparticles, GNPs, stabilized by the citrate groups showed 30 Å large particles having a homogeneous distribution of gold and citrate with a gold volume fraction of the order of 1%. On the average two BSA monomers are grafted at 2.4 GNPs. The exposed BSA-GNPs to SSE solution led to immediate mineralization of stable composite particles of the order of 0.2 μm diameter and a mineral volume fraction between 50% and 80%. The volume fraction of the mineral was of the order of 10(-5), which is roughly 3 times larger but an order of magnitude smaller than the maximum possible contents of respectively calcium phosphate and calcium carbonate in the SSE solution. Considering the extreme low solubility product of calcium phosphate, we suggest total calcium phosphate and partially (5-10%) calcium carbonate formation in the presence of BSA-GNPs.

  2. Small-angle neutron scattering studies of mineralization on BSA coated citrate capped gold nanoparticles used as a model surface for membrane scaling in RO wastewater desalination.

    PubMed

    Dahdal, Y N; Pipich, V; Rapaport, H; Oren, Y; Kasher, R; Schwahn, D

    2014-12-23

    Bovine serum albumin (BSA) coated on citrate capped gold nanoparticles (BSA-GNPs) was exposed to a simulated wastewater effluent (SSE) in order to study the mineralization and thereby mimic scaling at biofouled membranes of reverse osmosis (RO) wastewater desalination plants. RO is a leading technology of achieving freshwater quality as it has the capability of removing both dissolved inorganic salts and organic contaminants from tertiary wastewater effluents. The aim was to better understand one of the major problems facing this technology which is fouling of the membranes, mainly biofouling and scaling by calcium phosphate. The experiments were performed using the small-angle neutron scattering (SANS) technique. The nanoparticles, GNPs, stabilized by the citrate groups showed 30 Å large particles having a homogeneous distribution of gold and citrate with a gold volume fraction of the order of 1%. On the average two BSA monomers are grafted at 2.4 GNPs. The exposed BSA-GNPs to SSE solution led to immediate mineralization of stable composite particles of the order of 0.2 μm diameter and a mineral volume fraction between 50% and 80%. The volume fraction of the mineral was of the order of 10(-5), which is roughly 3 times larger but an order of magnitude smaller than the maximum possible contents of respectively calcium phosphate and calcium carbonate in the SSE solution. Considering the extreme low solubility product of calcium phosphate, we suggest total calcium phosphate and partially (5-10%) calcium carbonate formation in the presence of BSA-GNPs. PMID:25458085

  3. Calculating carbon mass balance from unsaturated soil columns treated with CaSO₄₋minerals: test of soil carbon sequestration.

    PubMed

    Han, Young-Soo; Tokunaga, Tetsu K

    2014-12-01

    Renewed interest in managing C balance in soils is motivated by increasing atmospheric concentrations of CO2 and consequent climate change. Here, experiments were conducted in soil columns to determine C mass balances with and without addition of CaSO4-minerals (anhydrite and gypsum), which were hypothesized to promote soil organic carbon (SOC) retention and soil inorganic carbon (SIC) precipitation as calcite under slightly alkaline conditions. Changes in C contents in three phases (gas, liquid and solid) were measured in unsaturated soil columns tested for one year and comprehensive C mass balances were determined. The tested soil columns had no C inputs, and only C utilization by microbial activity and C transformations were assumed in the C chemistry. The measurements showed that changes in C inventories occurred through two processes, SOC loss and SIC gain. However, the measured SOC losses in the treated columns were lower than their corresponding control columns, indicating that the amendments promoted SOC retention. The SOC losses resulted mostly from microbial respiration and loss of CO2 to the atmosphere rather than from chemical leaching. Microbial oxidation of SOC appears to have been suppressed by increased Ca(2+) and SO4(2)(-) from dissolution of CaSO4 minerals. For the conditions tested, SIC accumulation per m(2) soil area under CaSO4-treatment ranged from 130 to 260 g C m(-1) infiltrated water (20-120 g C m(-1) infiltrated water as net C benefit). These results demonstrate the potential for increasing C sequestration in slightly alkaline soils via CaSO4-treatment.

  4. Terrestrial nitrogen-carbon cycle interactions at the global scale.

    PubMed

    Zaehle, S

    2013-07-01

    Interactions between the terrestrial nitrogen (N) and carbon (C) cycles shape the response of ecosystems to global change. However, the global distribution of nitrogen availability and its importance in global biogeochemistry and biogeochemical interactions with the climate system remain uncertain. Based on projections of a terrestrial biosphere model scaling ecological understanding of nitrogen-carbon cycle interactions to global scales, anthropogenic nitrogen additions since 1860 are estimated to have enriched the terrestrial biosphere by 1.3 Pg N, supporting the sequestration of 11.2 Pg C. Over the same time period, CO2 fertilization has increased terrestrial carbon storage by 134.0 Pg C, increasing the terrestrial nitrogen stock by 1.2 Pg N. In 2001-2010, terrestrial ecosystems sequestered an estimated total of 27 Tg N yr(-1) (1.9 Pg C yr(-1)), of which 10 Tg N yr(-1) (0.2 Pg C yr(-1)) are due to anthropogenic nitrogen deposition. Nitrogen availability already limits terrestrial carbon sequestration in the boreal and temperate zone, and will constrain future carbon sequestration in response to CO2 fertilization (regionally by up to 70% compared with an estimate without considering nitrogen-carbon interactions). This reduced terrestrial carbon uptake will probably dominate the role of the terrestrial nitrogen cycle in the climate system, as it accelerates the accumulation of anthropogenic CO2 in the atmosphere. However, increases of N2O emissions owing to anthropogenic nitrogen and climate change (at a rate of approx. 0.5 Tg N yr(-1) per 1°C degree climate warming) will add an important long-term climate forcing.

  5. Terrestrial nitrogen-carbon cycle interactions at the global scale.

    PubMed

    Zaehle, S

    2013-07-01

    Interactions between the terrestrial nitrogen (N) and carbon (C) cycles shape the response of ecosystems to global change. However, the global distribution of nitrogen availability and its importance in global biogeochemistry and biogeochemical interactions with the climate system remain uncertain. Based on projections of a terrestrial biosphere model scaling ecological understanding of nitrogen-carbon cycle interactions to global scales, anthropogenic nitrogen additions since 1860 are estimated to have enriched the terrestrial biosphere by 1.3 Pg N, supporting the sequestration of 11.2 Pg C. Over the same time period, CO2 fertilization has increased terrestrial carbon storage by 134.0 Pg C, increasing the terrestrial nitrogen stock by 1.2 Pg N. In 2001-2010, terrestrial ecosystems sequestered an estimated total of 27 Tg N yr(-1) (1.9 Pg C yr(-1)), of which 10 Tg N yr(-1) (0.2 Pg C yr(-1)) are due to anthropogenic nitrogen deposition. Nitrogen availability already limits terrestrial carbon sequestration in the boreal and temperate zone, and will constrain future carbon sequestration in response to CO2 fertilization (regionally by up to 70% compared with an estimate without considering nitrogen-carbon interactions). This reduced terrestrial carbon uptake will probably dominate the role of the terrestrial nitrogen cycle in the climate system, as it accelerates the accumulation of anthropogenic CO2 in the atmosphere. However, increases of N2O emissions owing to anthropogenic nitrogen and climate change (at a rate of approx. 0.5 Tg N yr(-1) per 1°C degree climate warming) will add an important long-term climate forcing. PMID:23713123

  6. Carbon mineralization and soil fertility at high altitude grasslands in the Bolivian Andean

    NASA Astrophysics Data System (ADS)

    Zornoza, R.; Muñoz, M. A.; Faz, A.

    2012-04-01

    The high grasslands of Apolobamba provide a natural habitat for a high number of wild and domestic camelids such as vicuna (Vicugna vicugna) and alpaca (Lama pacos) in Bolivia. Because of the importance of the camelid raising for the Apolobambás inhabitant economy, it is fundamental to determine the natural resources condition and their availability for the camelid support. The soil organic matter plays a crucial role in the maintenance of the soil fertility at high grasslands. On the other hand, soil respiration is the primary pathway for CO2 fixed by plants returning to the atmosphere and its study is essential to evaluate the soil organic matter mineralization and the global C cycle. Based on this, the objectives of this research were to: (i) evaluate the soil fertility and (ii) determine soil organic matter mineralization on the basis of CO2 releases in Apolobamba. Regarding the lastly vicuna censuses carried out in the studied area, eight representative zones with dissimilar vicuna densities were selected. Other characteristics were also considered to select the study zones: (1) alpaca densities, (2) vegetation communities (3) plant cover and (4) landscape and geo-morphological description. Soil samples from different samplings were collected. Soil respiration was determined at two temperatures: 15 °C (based on the highest atmosphere temperature that was registered in the area) and 25 °C, in order to monitor the increase in soil respiration (Q10). The physico-chemical soil results pointed out the good soil fertility. However, erosive processes could be taken place likely caused by the alpaca grazing. High total organic carbon contents were observed corresponding to the highest soil respiration at 15 °C. This observation was supported by the relationship found between the total organic carbon and the soil respiration. A noticeable increase of the soil respiration when the temperature increased 10 °C was reported (from 1083 ± 47 g C m-2 yr-1 at 15 °C to

  7. Infrared and Raman spectroscopic characterization of the carbonate bearing silicate mineral aerinite - Implications for the molecular structure

    NASA Astrophysics Data System (ADS)

    Frost, Ray L.; Scholz, Ricardo; López, Andrés

    2015-10-01

    The mineral aerinite is an interesting mineral because it contains both silicate and carbonate units which is unusual. It is also a highly colored mineral being bright blue/purple. We have studied aerinite using a combination of techniques which included scanning electron microscopy, energy dispersive X-ray analysis, Raman and infrared spectroscopy. Raman bands at 1049 and 1072 cm-1 are assigned to the carbonate symmetric stretching mode. This observation supports the concept of the non-equivalence of the carbonate units in the structure of aerinite. Multiple infrared bands at 1354, 1390 and 1450 cm-1 supports this concept. Raman bands at 933 and 974 cm-1 are assigned to silicon-oxygen stretching vibrations. Multiple hydroxyl stretching and bending vibrations show that water is in different molecular environments in the aerinite structure.

  8. Spectral reflectance of carbonate minerals and rocks in the visible and near infrared (0.35 - 2.55 microns) and its applications in carbonate petrology

    NASA Technical Reports Server (NTRS)

    Gaffey, S. J.

    1984-01-01

    Reflection spectroscopy in the visible and near infrared (0.35 to 2.55 micron) offers a rapid, inexpensive, nondestructive tool for determining the mineralogy and investigating the minor element chemistry of the hard-to-discriminate carbonate minerals, and can, in one step, provide information previously obtainable only by the combined application of two or more analytical techniques. When light interacts with a mineral certain wavelengths are preferentially absorbed. The number, positions, widths and relative intensities of these absorptions are diagnostic of the mineralogy and chemical composition of the sample. At least seven bands due to vibrations of the carbonate radical occur between 1.60 and 2.55 micron. Positions of these bands vary from one carbonae mineral to another and can be used for mineral identification. Cation mass is the primary factor controlling band position; cation radius plays a secondary role.

  9. Carbon mineralization in two ultisols amended with different sources and particle sizes of pyrolyzed biochar.

    PubMed

    Sigua, G C; Novak, J M; Watts, D W; Cantrell, K B; Shumaker, P D; Szögi, A A; Johnson, M G

    2014-05-01

    Biochar produced during pyrolysis has the potential to enhance soil fertility and reduce greenhouse gas emissions. The influence of biochar properties (e.g., particle size) on both short- and long-term carbon (C) mineralization of biochar remains unclear. There is minimal information on the potential effects of biochar particle sizes on their breakdowns by soil microorganism, so it is unknown if the particle size of biochar influences C mineralization rate and/or stability in soils. In order to evaluate the effect of different sources (BS) and particle sizes (BF) of biochar on C loss and/or stability in soils, an incubation study on C mineralization of different biochar sources and particle sizes was established using two soils (ST): Norfolk soil (fine loamy, kaolinitic, thermic, typic Kandiudults) and Coxville soil (fine loamy kaolinitic, thermic, Paleaquults). In separate incubation vessels, these soils were amended with one of two manure-based biochars (poultry litters, PL; swine solids, SS) or one of two lignocellulosic-based biochars (switchgrass, SG; pine chips, PC) which were processed into two particle sizes (dust, <0.42 mm; pellet, >2 mm). The amount of CO2 evolved varied significantly between soils (p≤0.0001); particle sizes (p≤0.0001) and the interactions of biochar source (p≤0.001) and forms of biochars (p≤0.0001) with soil types. Averaged across soils and sources of biochar, CO2-C evolved from dust-sized biochar (281 mg kg(-1)) was significantly higher than pellet-sized biochar (226 mg kg(-1)). Coxville soils with SS biochar produced the greatest average CO2-C of 428 mg kg(-1) and Norfolk soils with PC had the lowest CO2-C production (93 mg kg(-1)). Measured rates of carbon mineralization also varied with soils and sources of biochar (Norfolk: PL>SS>SG≥PC; Coxville: PC>SG>SS>PL). The average net CO2-C evolved from the Coxville soils (385 mg kg(-1)) was about threefold more than the CO2-C evolved from the Norfolk soils (123 mg kg(-1)). Our

  10. [Mineralization of soil organic carbon and its relationship with soil enzyme activities in apple orchard in Weibei].

    PubMed

    Jia, Man-Li; Guo, Hong; Li, Hui-Ke

    2014-07-01

    A total of 36 kinds of soil samples were collected from apple orchards under three kinds of management model, including clear tillage model, intercropping white clover model and intercropping small crown flower model, the mineralization of soil organic carbon and four kinds of soil enzymes activities were determined, and the relationship between the two parameters was also analyzed. The results showed that the soil organic carbon mineralization of all the three treatments was almost the same. The daily SOC mineralization rate first increased and then decreased, and finally tended to be stable. After 31 days incubation experiment, the maximum accumulative amount of SOC mineralization occurred in white clover treatment with 590 mg x kg(-1), followed by small crown flower treatment with 541 mg x kg(-1), and the minimum value was 367 mg x kg(-1) in the control treatment, and the accumulative amount of SOC mineralization decreased with increasing soil depth. Discovered by the first-order kinetics, the fitting parameter Cp value ranged from 0.252 to 2.74 g x kg(-1) and k value ranged from 0.019 to 0.051 d(-1), and the two grass treatments both showed significant difference in Cp value from the control treatment, and the soil invertase and cellulose activities showed obvious relationship with soil organic carbon mineralization.

  11. [Mineralization of soil organic carbon and its relationship with soil enzyme activities in apple orchard in Weibei].

    PubMed

    Jia, Man-Li; Guo, Hong; Li, Hui-Ke

    2014-07-01

    A total of 36 kinds of soil samples were collected from apple orchards under three kinds of management model, including clear tillage model, intercropping white clover model and intercropping small crown flower model, the mineralization of soil organic carbon and four kinds of soil enzymes activities were determined, and the relationship between the two parameters was also analyzed. The results showed that the soil organic carbon mineralization of all the three treatments was almost the same. The daily SOC mineralization rate first increased and then decreased, and finally tended to be stable. After 31 days incubation experiment, the maximum accumulative amount of SOC mineralization occurred in white clover treatment with 590 mg x kg(-1), followed by small crown flower treatment with 541 mg x kg(-1), and the minimum value was 367 mg x kg(-1) in the control treatment, and the accumulative amount of SOC mineralization decreased with increasing soil depth. Discovered by the first-order kinetics, the fitting parameter Cp value ranged from 0.252 to 2.74 g x kg(-1) and k value ranged from 0.019 to 0.051 d(-1), and the two grass treatments both showed significant difference in Cp value from the control treatment, and the soil invertase and cellulose activities showed obvious relationship with soil organic carbon mineralization. PMID:25244868

  12. Carbonate-hosted nonsulphide Zn-Pb mineralization of southern British Columbia, Canada

    NASA Astrophysics Data System (ADS)

    Paradis, Suzanne; Keevil, Halley; Simandl, George J.; Raudsepp, Mati

    2015-12-01

    Many carbonate-hosted sulphide deposits in the Salmo district of southern British Columbia have near-surface Zn- and Pb-bearing iron oxide-rich gossans. The gossans formed when carbonate-hosted, base metal sulphides were subjected to intense supergene weathering processes and metals were liberated by the oxidation of sulphide minerals. Two types of supergene carbonate-hosted nonsulphide deposits, direct replacement (`red ore') and wallrock replacement (`white ore'), are present in the Salmo district. The direct replacement deposits formed by the oxidation of primary sulphides; the base metals passed into solution and were redistributed and trapped within the space occupied by the oxidized portion of the sulphide protore. Depending on the extent of replacement of the sulphides by Zn-, Pb- and Fe-bearing oxides, silicates, carbonates and phosphates, the resulting ore can be called `mixed' (sulphides and nonsulphides) or simply `nonsulphide'. The wallrock replacement deposits formed when base metals liberated by the oxidation of sulphides were transported by circulating supergene solutions down and/or away from the sulphides to form wallrock replacement deposits. The direct replacement nonsulphide zones of the Salmo district overlay the sulphide bodies in which they replaced the sulphides and carbonates, forming large irregular replacement masses, encrustations and open-space fillings. They consist predominantly of hematite, goethite, hemimorphite [Zn4Si2O7(OH)2·H2O], minor hydrozincite [Zn5(CO3)2(OH)6], cerussite [PbCO3] and traces of willemite [Zn2SiO4]. The wallrock replacement zones consist mainly of hemimorphite with local occurrences of iron oxides, hopeite [Zn3(PO4)2·4H2O] and tarbuttite [Zn2(PO4)(OH)]. No remnants of sulphides were observed in the replacement zones. The Salmo nonsulphide deposits were formed by prolonged weathering of Mississippi Valley-type (MVT) mineralization that underwent dissolution and oxidation of the pyrite, sphalerite and galena

  13. Amino acid diagenesis, organic carbon and nitrogen mineralization in surface sediments from the inner Oslofjord, Norway

    SciTech Connect

    Haugen, J.E. ); Lichtentaler, R. )

    1991-06-01

    Total hydrolyzed amino acids (THAA), total organic carbon (TOC), and total nitrogen (TN) have been measured in an oxic and anoxic surface sediment from the inner Oslofjord. Downcore variations of these parameters are ascribed to both diagenesis and changes in organic matter supply, the latter being most important. These changes are most prominent in the anoxic sediment, which reflects the eutrophication history of the innermost part of the fjord. Downcore, THAA content decreased from 3.8 to 2.0 mg/g (salt-free dry weight) in the oxic sediment and from 22.3 to 3.8 mg/g in the anoxic sediment. Total amino acid nitrogen varied between 17 and 34% of total nitrogen in the oxic, and 25 and 54% in the anoxic, sediment. Organic carbon and organic nitrogen accumulation rates and depth integrated mineralization rates are about three times higher in the anoxic sediment than in the oxic sediment. Recycling of amino acids accounted for 4 to 12% of the total organic carbon and 13 to 40% of the total organic nitrogen regenerated in these sediments.

  14. Heterocystous Cyanobacteria in Microbialites Play an Important Role in N2 Fixation and Carbonate Mineral Precipitation

    NASA Astrophysics Data System (ADS)

    Alcantara-Hernandez, R. J.

    2015-12-01

    Lake Alchichica is a maars type crater-lake located in Central Mexico (pH > 8.9, EC ~13.39 mS cm-1). This limnological system harbors two types of microbialites that can be found around the entire perimeter of the lake (Fig. 1). These structures are representative examples of complex and diverse microbiological assemblages, where microbial activity promotes lithification by trapping, binding and/or precipitating detrital or chemical sediments. Previous studies determined that the microbialites of Lake Alchichica fix N2 to thrive under the N-limiting conditions of the lake, and that these nitrogenase activity peaks are related to heterocystous cyanobacteria that couple photosynthesis to N2 fixation during daylight periods. Heterocystous cyanobacteria (Nostocales) together with Oscillatoriales (non-heterocystous filamentous cyanobacteria) and other cyanobacterial groups have been described as the most abundant cyanobacteria in Alchichica microbialites, and in lithifying mats. Our results suggest that heterocystous cyanobacteria play an important role not only by fixing N2 for biomass construction, but also because their heterocysts host in their external cell membranes main sites for carbonate mineral precipitation including calcium carbonates and siderite. Previous research has shown that the heterocyst is the specialized site for cellular respiration associated to the pH decrease of vegetative/photosynthetic cells, contributing thus to the precipitation of carbonates and the accretion of the organosedimentary structure

  15. Molecular interactions of SO2 with carbonate minerals under co-sequestration conditions: a combined experimental and theoretical study

    SciTech Connect

    Glezakou, Vassiliki Alexandra; McGrail, B. Peter; Schaef, Herbert T.

    2012-09-01

    We present a combined experimental and theoretical study investigating the reactivity between selected and morphologically important surfaces of carbonate minerals with supercritical CO2 with co-existing H2O and SO2. Trace amounts of SO2 cause formation of CaSO3 in the form of hannebachite in the initial stages of SO2 adsorption and transformation. Atomistic simulations of these initial steps indicate a somewhat catalytic activity of water, which is enhanced by the presence of Magnesium atoms in the mineral surface. Under co-sequestration conditions, traces of water are not likely to cause carbonate dissolution, however the presence of SO2 greatly stabilizes the sulfite product.

  16. SIMULTANEOUS MECHANICAL AND HEAT ACTIVATION: A NEW ROUTE TO ENHANCE SERPENTINE CARBONATION REACTIVITY AND LOWER CO2 MINERAL SEQUESTRATION PROCESS COST

    SciTech Connect

    M.J. McKelvy; J. Diefenbacher; R. Nunez; R.W. Carpenter; A.V.G. Chizmeshya

    2005-01-01

    Coal can support a large fraction of global energy demands for centuries to come, if the environmental problems associated with CO{sub 2} emissions can be overcome. Unlike other candidate technologies, which propose long-term storage (e.g., ocean and geological sequestration), mineral sequestration permanently disposes of CO{sub 2} as geologically stable mineral carbonates. Only benign, naturally occurring materials are formed, eliminating long-term storage and liability issues. Serpentine carbonation is a leading mineral sequestration process candidate, which offers large scale, permanent sequestration. Deposits exceed those needed to carbonate all the CO{sub 2} that could be generated from global coal reserves, and mining and milling costs are reasonable ({approx}$4 to $5/ton). Carbonation is exothermic, providing exciting low-cost process potential. The remaining goal is to develop an economically viable process. An essential step in this development is increasing the carbonation reaction rate and degree of completion, without substantially impacting other process costs. Recently, the Albany Research Center (ARC) has accelerated serpentine carbonation, which occurs naturally over geological time, to near completion in less than an hour. While reaction rates for natural serpentine have been found to be too slow for practical application, both heat and mechanical (attrition grinding) pretreatment were found to substantially enhance carbonation reactivity. Unfortunately, these processes are too energy intensive to be cost-effective in their present form. In this project we explored the potential that utilizing power plant waste heat (e.g., available up to {approx}200-250 C) during mechanical activation (i.e., thermomechanical activation) offers to enhance serpentine mineral carbonation, while reducing pretreatment energy consumption and process cost. This project was carried out in collaboration with the Albany Research Center (ARC) to maximize the insight into the

  17. Microbial carbon mineralization in tropical lowland and montane forest soils of Peru

    PubMed Central

    Whitaker, Jeanette; Ostle, Nicholas; McNamara, Niall P.; Nottingham, Andrew T.; Stott, Andrew W.; Bardgett, Richard D.; Salinas, Norma; Ccahuana, Adan J. Q.; Meir, Patrick

    2014-01-01

    Climate change is affecting the amount and complexity of plant inputs to tropical forest soils. This is likely to influence the carbon (C) balance of these ecosystems by altering decomposition processes e.g., “positive priming effects” that accelerate soil organic matter mineralization. However, the mechanisms determining the magnitude of priming effects are poorly understood. We investigated potential mechanisms by adding 13C labeled substrates, as surrogates of plant inputs, to soils from an elevation gradient of tropical lowland and montane forests. We hypothesized that priming effects would increase with elevation due to increasing microbial nitrogen limitation, and that microbial community composition would strongly influence the magnitude of priming effects. Quantifying the sources of respired C (substrate or soil organic matter) in response to substrate addition revealed no consistent patterns in priming effects with elevation. Instead we found that substrate quality (complexity and nitrogen content) was the dominant factor controlling priming effects. For example a nitrogenous substrate induced a large increase in soil organic matter mineralization whilst a complex C substrate caused negligible change. Differences in the functional capacity of specific microbial groups, rather than microbial community composition per se, were responsible for these substrate-driven differences in priming effects. Our findings suggest that the microbial pathways by which plant inputs and soil organic matter are mineralized are determined primarily by the quality of plant inputs and the functional capacity of microbial taxa, rather than the abiotic properties of the soil. Changes in the complexity and stoichiometry of plant inputs to soil in response to climate change may therefore be important in regulating soil C dynamics in tropical forest soils. PMID:25566230

  18. Microbial carbon mineralization in tropical lowland and montane forest soils of Peru.

    PubMed

    Whitaker, Jeanette; Ostle, Nicholas; McNamara, Niall P; Nottingham, Andrew T; Stott, Andrew W; Bardgett, Richard D; Salinas, Norma; Ccahuana, Adan J Q; Meir, Patrick

    2014-01-01

    Climate change is affecting the amount and complexity of plant inputs to tropical forest soils. This is likely to influence the carbon (C) balance of these ecosystems by altering decomposition processes e.g., "positive priming effects" that accelerate soil organic matter mineralization. However, the mechanisms determining the magnitude of priming effects are poorly understood. We investigated potential mechanisms by adding (13)C labeled substrates, as surrogates of plant inputs, to soils from an elevation gradient of tropical lowland and montane forests. We hypothesized that priming effects would increase with elevation due to increasing microbial nitrogen limitation, and that microbial community composition would strongly influence the magnitude of priming effects. Quantifying the sources of respired C (substrate or soil organic matter) in response to substrate addition revealed no consistent patterns in priming effects with elevation. Instead we found that substrate quality (complexity and nitrogen content) was the dominant factor controlling priming effects. For example a nitrogenous substrate induced a large increase in soil organic matter mineralization whilst a complex C substrate caused negligible change. Differences in the functional capacity of specific microbial groups, rather than microbial community composition per se, were responsible for these substrate-driven differences in priming effects. Our findings suggest that the microbial pathways by which plant inputs and soil organic matter are mineralized are determined primarily by the quality of plant inputs and the functional capacity of microbial taxa, rather than the abiotic properties of the soil. Changes in the complexity and stoichiometry of plant inputs to soil in response to climate change may therefore be important in regulating soil C dynamics in tropical forest soils. PMID:25566230

  19. Impact-Induced Shock-Stress Effects in Cometary Analogue Olivine, Pyroxene, Carbonate and Serpentine Minerals

    NASA Astrophysics Data System (ADS)

    Lederer, Susan M.; Jensen, Elizabeth A.; Fane, Michael; Strojia, Cierra; Smith, Douglas C.; Keller, Lindsay P.; Lindsay, Sean S.; Wooden, Diane H.; Cintala, Mark J.; Zolensky, Michael E.

    2014-11-01

    The primary goal of the Stardust mission was to collect dust particles as the spacecraft flew past Comet 81P/Wild 2. The morphologies of several returned grains of forsterite and enstatite suggest that they have experienced shock effects due to collisions (Jacobs et al. MAPS 44, 2009; Keller et al., GCA 72, 2008; Tomeoka et al, MAPS 43, 2008). Because the particles were collected at an encounter speed of ~6 km/s, it was natural to question whether the collection process itself generated those microstructural shock features or if they were sustained prior to their capture in the aerogel. Analyses of the grains suggest the latter, namely, that the particles had undergone high-velocity impacts sometime before their capture.With this in mind, unshocked minerals were impacted with the vertical gun in the NASA Johnson Space Center Experimental Impact Laboratory at 2.0 - 2.8 km/s, speeds that a typical comet might experience during its tenure in the Kuiper Belt (Stern 2002). Targets included minerals found in cometary dust and asteroids, including magnesium-rich pyroxenes (enstatite and diopside), magnesium-rich olivine (forsterite), carbonates (magnesite and siderite), and serpentine. Projectiles were Al2O3 spheres. Transmission electron microscope (TEM) imaging of experimentally shocked forsterite and enstatite samples reveal morphologies and densities of planar dislocations similar to those of the Stardust samples. Comparisons between TEM images of the Stardust grains and those of the experimentally shocked minerals will be presented.Funding was provided by the NASA PG&G grant 09-PGG09-0115, NSF grant AST-1010012, and a Cottrell College Scholarship through the Research Corporation. Special thanks to the NASA EIL staff, F. Cardenas and R. Montes.

  20. Controllable stabilization of poly(N-isopropylacrylamide)-based microgel films through biomimetic mineralization of calcium carbonate.

    PubMed

    Xia, Yongqing; Gu, Yanfeng; Zhou, Xuan; Xu, Hai; Zhao, Xiubo; Yaseen, Mohammed; Lu, Jian Ren

    2012-08-13

    Two types of thermoresponsive microgels, poly(N-isopropylacrylamide) (PNIPAM) microgels and poly(N-isopropylacrylamide-co-acrylic acid) (PNIPAMAC) microgels were synthesized and used as templates for the mineralization of amorphous calcium carbonate (ACC) by diffusion of CO(2) vapor under ambient conditions. Thermosensitive PNIPAM/CaCO(3) hybrid macroscopic hydrogels and micrometer-sized PNIPAMAC/CaCO(3) hybrid microgels were controllably obtained and different mineralization mechanistic processes were proposed. The impact of the loaded CaCO(3) on the size, morphology, stability, and thermosensitivity of the microgels was also analyzed. PNIPAM/CaCO(3) hybrid macrogels had a slight decrease in thermoresponsive phase transition temperature, while PNIPAMAC/CaCO(3) hybrid microgels showed a clear increase in phase transition temperature. The difference reflected different amount and location of ACC in the gel network, causing different interactions with polymer chains. The PNIPAMAC/CaCO(3) microgels formed stable monolayer films on bare silica wafers and glass coverslips upon drying. The microgel films could facilitate the attachment and growth of 3T3 fibroblast cells and their subsequent detachment upon temperature drop from 37 °C to the ambient condition around 20 °C, thus, offering a convenient procedure for cell harvesting. PMID:22715987

  1. Redistribution of soil water by a saprotrophic fungus enhances carbon mineralization

    PubMed Central

    Guhr, Alexander; Borken, Werner; Spohn, Marie; Matzner, Egbert

    2015-01-01

    The desiccation of upper soil horizons is a common phenomenon, leading to a decrease in soil microbial activity and mineralization. Recent studies have shown that fungal communities and fungal-based food webs are less sensitive and better adapted to soil desiccation than bacterial-based food webs. One reason for a better fungal adaptation to soil desiccation may be hydraulic redistribution of water by mycelia networks. Here we show that a saprotrophic fungus (Agaricus bisporus) redistributes water from moist (–0.03 MPa) into dry (–9.5 MPa) soil at about 0.3 cm⋅min−1 in single hyphae, resulting in an increase in soil water potential after 72 h. The increase in soil moisture by hydraulic redistribution significantly enhanced carbon mineralization by 2,800% and enzymatic activity by 250–350% in the previously dry soil compartment within 168 h. Our results demonstrate that hydraulic redistribution can partly compensate water deficiency if water is available in other zones of the mycelia network. Hydraulic redistribution is likely one of the mechanisms behind higher drought resistance of soil fungi compared with bacteria. Moreover, hydraulic redistribution by saprotrophic fungi is an underrated pathway of water transport in soils and may lead to a transfer of water to zones of high fungal activity. PMID:26554004

  2. Single-walled carbon nanotubes functionalized with sodium hyaluronate enhance bone mineralization.

    PubMed

    Sá, M A; Ribeiro, H J; Valverde, T M; Sousa, B R; Martins-Júnior, P A; Mendes, R M; Ladeira, L O; Resende, R R; Kitten, G T; Ferreira, A J

    2016-02-01

    The aim of this study was to evaluate the effects of sodium hyaluronate (HY), single-walled carbon nanotubes (SWCNTs) and HY-functionalized SWCNTs (HY-SWCNTs) on the behavior of primary osteoblasts, as well as to investigate the deposition of inorganic crystals on titanium surfaces coated with these biocomposites. Primary osteoblasts were obtained from the calvarial bones of male newborn Wistar rats (5 rats for each cell extraction). We assessed cell viability using the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl-2H-tetrazolium bromide assay and by double-staining with propidium iodide and Hoechst. We also assessed the formation of mineralized bone nodules by von Kossa staining, the mRNA expression of bone repair proteins, and the deposition of inorganic crystals on titanium surfaces coated with HY, SWCNTs, or HY-SWCNTs. The results showed that treatment with these biocomposites did not alter the viability of primary osteoblasts. Furthermore, deposition of mineralized bone nodules was significantly increased by cells treated with HY and HY-SWCNTs. This can be partly explained by an increase in the mRNA expression of type I and III collagen, osteocalcin, and bone morphogenetic proteins 2 and 4. Additionally, the titanium surface treated with HY-SWCNTs showed a significant increase in the deposition of inorganic crystals. Thus, our data indicate that HY, SWCNTs, and HY-SWCNTs are potentially useful for the development of new strategies for bone tissue engineering.

  3. Single-walled carbon nanotubes functionalized with sodium hyaluronate enhance bone mineralization

    PubMed Central

    Sá, M.A.; Ribeiro, H.J.; Valverde, T.M.; Sousa, B.R.; Martins-Júnior, P.A.; Mendes, R.M.; Ladeira, L.O.; Resende, R.R.; Kitten, G.T.; Ferreira, A.J.

    2015-01-01

    The aim of this study was to evaluate the effects of sodium hyaluronate (HY), single-walled carbon nanotubes (SWCNTs) and HY-functionalized SWCNTs (HY-SWCNTs) on the behavior of primary osteoblasts, as well as to investigate the deposition of inorganic crystals on titanium surfaces coated with these biocomposites. Primary osteoblasts were obtained from the calvarial bones of male newborn Wistar rats (5 rats for each cell extraction). We assessed cell viability using the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl-2H-tetrazolium bromide assay and by double-staining with propidium iodide and Hoechst. We also assessed the formation of mineralized bone nodules by von Kossa staining, the mRNA expression of bone repair proteins, and the deposition of inorganic crystals on titanium surfaces coated with HY, SWCNTs, or HY-SWCNTs. The results showed that treatment with these biocomposites did not alter the viability of primary osteoblasts. Furthermore, deposition of mineralized bone nodules was significantly increased by cells treated with HY and HY-SWCNTs. This can be partly explained by an increase in the mRNA expression of type I and III collagen, osteocalcin, and bone morphogenetic proteins 2 and 4. Additionally, the titanium surface treated with HY-SWCNTs showed a significant increase in the deposition of inorganic crystals. Thus, our data indicate that HY, SWCNTs, and HY-SWCNTs are potentially useful for the development of new strategies for bone tissue engineering. PMID:26648087

  4. Calcium Carbonate Mineralized Nanoparticles as an Intracellular Transporter of Cytochrome c for Cancer Therapy.

    PubMed

    Koo, Ahn Na; Min, Kyung Hyun; Lee, Hong Jae; Jegal, Jun Ho; Lee, Jae Won; Lee, Sang Cheon

    2015-11-01

    A new intracellular delivery system based on an apoptotic protein-loaded calcium carbonate (CaCO3 ) mineralized nanoparticle (MNP) is described. Apoptosis-inducing cytochrome c (Cyt c) loaded CaCO3 MNPs (Cyt c MNPs) were prepared by block copolymer mediated in situ CaCO3 mineralization in the presence of Cyt c. The resulting Cyt c MNPs had a vaterite polymorph of CaCO3 with a mean hydrodynamic diameter of 360.5 nm and exhibited 60% efficiency for Cyt c loading. The Cyt c MNPs were stable at physiological pH (pH 7.4) and effectively prohibited the release of Cyt c, whereas, at intracellular endosomal pH (pH 5.0), Cyt c release was facilitated. The MNPs enable the endosomal escape of Cyt c for effective localization of Cyt c in the cytosols of MCF-7 cells. Flow cytometry showed that the Cyt c MNPs effectively induced apoptosis of MCF-7 cells. These findings indicate that the CaCO3 MNPs can meet the prerequisites for delivery of cell-impermeable therapeutic proteins for cancer therapy.

  5. Redistribution of soil water by a saprotrophic fungus enhances carbon mineralization.

    PubMed

    Guhr, Alexander; Borken, Werner; Spohn, Marie; Matzner, Egbert

    2015-11-24

    The desiccation of upper soil horizons is a common phenomenon, leading to a decrease in soil microbial activity and mineralization. Recent studies have shown that fungal communities and fungal-based food webs are less sensitive and better adapted to soil desiccation than bacterial-based food webs. One reason for a better fungal adaptation to soil desiccation may be hydraulic redistribution of water by mycelia networks. Here we show that a saprotrophic fungus (Agaricus bisporus) redistributes water from moist (-0.03 MPa) into dry (-9.5 MPa) soil at about 0.3 cm ⋅ min(-1) in single hyphae, resulting in an increase in soil water potential after 72 h. The increase in soil moisture by hydraulic redistribution significantly enhanced carbon mineralization by 2,800% and enzymatic activity by 250-350% in the previously dry soil compartment within 168 h. Our results demonstrate that hydraulic redistribution can partly compensate water deficiency if water is available in other zones of the mycelia network. Hydraulic redistribution is likely one of the mechanisms behind higher drought resistance of soil fungi compared with bacteria. Moreover, hydraulic redistribution by saprotrophic fungi is an underrated pathway of water transport in soils and may lead to a transfer of water to zones of high fungal activity.

  6. Carbon mineralization and distribution of nutrients within different particle-size fractions of commercially produced olive mill pomace.

    PubMed

    Gómez-Muñoz, Beatriz; Bol, Roland; Hatch, David; García-Ruiz, Roberto

    2011-11-01

    Composting is a realistic option for disposal of olive mill pomace (OMP) by making it suitable as a soil amendment for organic farming. The chemical and physical characteristics and contribution of particle-size fractions to total nutrients and carbon mineralization of seven commercial composts of OMP (COMP) were investigated. Higher proportions of manure, co-composted with OMP, reduced the organic matter (OM), total carbon and C:N ratio of the product, but increased the content of nutrients and fine particles. The fine particles had higher nutrient contents, but less OM and carbon and, unlike larger particles, did not exhibit any phytotoxicity. Less than 1.5% of added carbon was mineralized in whole compost, but a lower rate was found with larger particles. Separation of COMP by particle size fractionation and application as a soil conditioner is recommended for better optimization of COMP with the <1mm fraction providing the higher quality compost. PMID:21890354

  7. Large fluxes and rapid turnover of mineral-associated carbon across topographic gradients in a humid tropical forest: insights from paired 14C analysis

    NASA Astrophysics Data System (ADS)

    Hall, S. J.; McNicol, G.; Natake, T.; Silver, W. L.

    2015-04-01

    It has been proposed that the large soil carbon (C) stocks of humid tropical forests result predominantly from C stabilization by reactive minerals, whereas oxygen (O2) limitation of decomposition has received much less attention. We examined the importance of these factors in explaining patterns of C stocks and turnover in the Luquillo Experimental Forest, Puerto Rico, using radiocarbon (14C) measurements of contemporary and archived samples. Samples from ridge, slope, and valley positions spanned three soil orders (Ultisol, Oxisol, Inceptisol) representative of humid tropical forests, and differed in texture, reactive metal content, O2 availability, and root biomass. Mineral-associated C comprised the large majority (87 ± 2%, n = 30) of total soil C. Turnover of most mineral-associated C (66 ± 2%) was rapid (11 to 26 years; mean and SE: 18 ± 3 years) in 25 of 30 soil samples across surface horizons (0-10 and 10-20 cm depths) and all topographic positions, independent of variation in reactive metal concentrations and clay content. Passive C with centennial-millennial turnover was typically much less abundant (34 ± 3%), even at 10-20 cm depths. Carbon turnover times and concentrations significantly increased with concentrations of reduced iron (Fe(II)) across all samples, suggesting that O2 availability may have limited the decomposition of mineral-associated C over decadal scales. Steady-state inputs of mineral-associated C were statistically similar among the three topographic positions, and could represent 10-25% of annual litter production. Observed trends in mineral-associated Δ14C over time could not be fit using the single-pool model used in many other studies, which generated contradictory relationships between turnover and Δ14C as compared with a more realistic two-pool model. The large C fluxes in surface and near-surface soils documented here are supported by findings from paired 14C studies in other types of ecosystems, and suggest that most

  8. Large fluxes and rapid turnover of mineral-associated carbon across topographic gradients in a humid tropical forest: insights from paired 14C analysis

    DOE PAGESBeta

    Hall, S. J.; McNicol, G.; Natake, T.; Silver, W. L.

    2015-04-29

    It has been proposed that the large soil carbon (C) stocks of humid tropical forests result predominantly from C stabilization by reactive minerals, whereas oxygen (O2) limitation of decomposition has received much less attention. We examined the importance of these factors in explaining patterns of C stocks and turnover in the Luquillo Experimental Forest, Puerto Rico, using radiocarbon (14C) measurements of contemporary and archived samples. Samples from ridge, slope, and valley positions spanned three soil orders (Ultisol, Oxisol, Inceptisol) representative of humid tropical forests, and differed in texture, reactive metal content, O2 availability, and root biomass. Mineral-associated C comprised themore » large majority (87 ± 2%, n = 30) of total soil C. Turnover of most mineral-associated C (66 ± 2%) was rapid (11 to 26 years; mean and SE: 18 ± 3 years) in 25 of 30 soil samples across surface horizons (0–10 and 10–20 cm depths) and all topographic positions, independent of variation in reactive metal concentrations and clay content. Passive C with centennial–millennial turnover was typically much less abundant (34 ± 3%), even at 10–20 cm depths. Carbon turnover times and concentrations significantly increased with concentrations of reduced iron (Fe(II)) across all samples, suggesting that O2 availability may have limited the decomposition of mineral-associated C over decadal scales. Steady-state inputs of mineral-associated C were statistically similar among the three topographic positions, and could represent 10–25% of annual litter production. Observed trends in mineral-associated Δ14C over time could not be fit using the single-pool model used in many other studies, which generated contradictory relationships between turnover and Δ14C as compared with a more realistic two-pool model. The large C fluxes in surface and near-surface soils documented here are supported by findings from paired 14C studies in other types of ecosystems, and

  9. Up-Scaling Geochemical Reaction Rates for Carbon Dioxide (CO2) in Deep Saline Aquifers

    SciTech Connect

    Peters, Catherine A

    2013-02-28

    Geochemical reactions in deep subsurface environments are complicated by the consolidated nature and mineralogical complexity of sedimentary rocks. Understanding the kinetics of these reactions is critical to our ability to make long-term predictions about subsurface processes such as pH buffering, alteration in rock structure, permeability changes, and formation of secondary precipitates. In this project, we used a combination of experiments and numerical simulation to bridge the gap between our knowledge of these reactions at the lab scale and rates that are meaningful for modeling reactive transport at core scales. The focus is on acid-driven mineral dissolution, which is specifically relevant in the context of CO2-water-rock interactions in geological sequestration of carbon dioxide. The project led to major findings in three areas. First, we modeled reactive transport in pore-network systems to investigate scaling effects in geochemical reaction rates. We found significant scaling effects when CO2 concentrations are high and reaction rates are fast. These findings indicate that the increased acidity associated with geological sequestration can generate conditions for which proper scaling tools are yet to be developed. Second, we used mathematical modeling to investigate the extent to which SO2, if co-injected with CO2, would acidify formation brines. We found that there exist realistic conditions in which the impact on brine acidity will be limited due to diffusion rate-limited SO2 dissolution from the CO2 phase, and the subsequent pH shift may also be limited by the lack of availability of oxidants to produce sulfuric acid. Third, for three Viking sandstones (Alberta sedimentary basin, Canada), we employed backscattered electron microscopy and energy dispersive X-ray spectroscopy to statistically characterize mineral contact with pore space. We determined that for reactive minerals in sedimentary consolidated rocks, abundance alone is not a good predictor of

  10. Soil Organic Carbon Mapping by Geostatistics in Europe Scale

    NASA Astrophysics Data System (ADS)

    Aksoy, E.; Panagos, P.; Montanarella, L.

    2013-12-01

    Accuracy in assessing the distribution of soil organic carbon (SOC) is an important issue because SOC is an important soil component that plays key roles in the functions of both natural ecosystems and agricultural systems. The SOC content varies from place to place and it is strongly related with climate variables (temperature and rainfall), terrain features, soil texture, parent material, vegetation, land-use types, and human management (management and degradation) at different spatial scales. Geostatistical techniques allow for the prediction of soil properties using soil information and environmental covariates. In this study, assessment of SOC distribution has been predicted with Regression-Kriging method in Europe scale. In this prediction, combination of the soil samples which were collected from the LUCAS (European Land Use/Cover Area frame statistical Survey) & BioSoil Projects, with local soil data which were collected from six different CZOs in Europe and ten spatial predictors (slope, aspect, elevation, CTI, CORINE land-cover classification, parent material, texture, WRB soil classification, annual average temperature and precipitation) were used. Significant correlation between the covariates and the organic carbon dependent variable was found. Moreover, investigating the contribution of local dataset in watershed scale into regional dataset in European scale was an important challenge.

  11. Method of producing carbon coated nano- and micron-scale particles

    DOEpatents

    Perry, W. Lee; Weigle, John C; Phillips, Jonathan

    2013-12-17

    A method of making carbon-coated nano- or micron-scale particles comprising entraining particles in an aerosol gas, providing a carbon-containing gas, providing a plasma gas, mixing the aerosol gas, the carbon-containing gas, and the plasma gas proximate a torch, bombarding the mixed gases with microwaves, and collecting resulting carbon-coated nano- or micron-scale particles.

  12. Enabling the measurement of in-situ, atomic scale mineral transformation rates in supercritical CO2 through development of a high pressure AFM

    NASA Astrophysics Data System (ADS)

    Lea, S.; Higgins, S. R.; Knauss, K. G.; Rosso, K. M.

    2010-12-01

    Capture and storage of carbon dioxide in deep geologic formations represents one promising scenario for minimizing the impacts of greenhouse gases on global warming. The ability to demonstrate that CO2 will remain stored in the geological formation over the long-term is needed in support of widespread implementation decisions, and knowledge of mineral-fluid chemical transformation rates is an essential aspect. The majority of previous research on mineral-fluid interactions has focused primarily on the reactivity of minerals in aqueous solutions containing various amounts of dissolved CO2. Long-term caprock integrity, however, could also be dictated by mineral transformations occurring in low-water environments dominated by the supercritical CO2 (scCO2) fluid phase, which is expected to slowly displace or dessicate residual aqueous solution at the caprock-fluid interface. Many of the mechanisms of mineral interfacial reactions with hydrated or water-saturated scCO2 are unknown and there are unique challenges to obtain kinetic and thermodynamic data for mineral transformation reactions in these fluids. We are developing a high-pressure atomic force microscope (AFM) that will enable in-situ, atomic scale measurements of metal carbonate nucleation and growth rates on mineral surfaces in contact with hydrated scCO2 fluids. This apparatus is based on the hydrothermal AFM that was developed by Higgins et al.1, but includes some enhancements and is designed to handle pressures up to 100 bar. The noise in our optically-based cantilever deflection detection scheme is subject to perturbations in the density (due to index of refraction dependence) of the compressible supercritical fluid. Consequently, variations in temperature and pressure within the fluid cell are a primary technical challenge with possible significant impact in imaging resolution. We demonstrate with our test fluid cell that the equivalent rms noise in the deflection signal is similar to (and in some cases

  13. Effects of platinum from vehicle exhaust catalyst on carbon and nitrogen mineralization in soils.

    PubMed

    Kalbitz, Karsten; Schwesig, David; Wang, Wenxia

    2008-11-01

    There is strong evidence of continuously increasing contamination of soils with platinum group elements (PGE), in particular with platinum (Pt) from vehicle exhaust catalysts in roadside soils. However, knowledge about the effects of Pt contamination on soil processes is very limited. The objective of this study was to investigate whether the contamination of soils with Pt at realistic environmental levels leads to observable adverse effects on selected indicator parameters of the carbon and nitrogen turnover in soils. Incubation experiments with artificially contaminated soils and solutions containing dissolved organic matter (DOM) were carried out by the use of milled material from a Pt-containing vehicle exhaust catalyst. Interaction of the catalyst material with the soil resulted in a mobilization of Pt into the dissolved phase reaching up to 0.1% of the added Pt. The amount of Pt mobilization seemed to be mainly driven by the pH of the soil. Mineralization of carbon and nitrogen did not reveal any significant adverse effect of the Pt addition as compared to the control samples. Future studies dealing with Pt effects on soil processes should focus on environmental conditions favoring Pt mobilization, e.g. such as very low pH values or large concentrations of DOM.

  14. Geochemistry of metastable carbonate minerals from the Brush Creek marine interval (Missourian), Indiana County, Pennsylvania

    SciTech Connect

    Cercone, K.R.; Kime, A.; Mutchler, S.; Rittle, K. )

    1991-08-01

    Many marine fossils from the Missourian Brush Creek interval of western Pennsylvania display partial preservation of metastable aragonite and high-magnesium calcite shell material. Bivalve mollusks have been shown by x-ray diffraction to contain as much as 96% aragonite, with lesser amounts of both high-magnesium and low-magnesium calcite. Stable carbon and oxygen isotopic ratios from these bivalves suggest they precipitated in equilibrium with Pennsylvanian ocean water. The bellerophontid Pharkidonotus, which exhibits partial recrystallization textures under scanning electron microscopy, consists of 45% aragonite and 55% low-magnesium calcite, and has slightly more depleted isotopic values than bivalves. Crinoids also appear to have been partially recrystallized, resulting in a mixture of primary high-magnesium calcite and secondary low-magnesium calcite and microdolomite, with much of the original shell structure still preserved. The degree of preservation of metastable carbonate minerals varies both stratigraphically and spatially within the Brush Creek interval. Maximum preservation occurs in organic-rich shales deposited in low-lying areas of the Brush Creek sea floor. The preservation of aragonite and high-magnesium calcite in such units may have resulted from a lack of circulating porewater during early diagenesis.

  15. Bacterially induced mineralization of calcium carbonate: the role of exopolysaccharides and capsular polysaccharides.

    PubMed

    Ercole, Claudia; Cacchio, Paola; Botta, Anna Lucia; Centi, Valeria; Lepidi, Aldo

    2007-02-01

    Bacterially induced carbonate mineralization has been proposed as a new method for the restoration of limestones in historic buildings and monuments. We describe here the formation of calcite crystals by extracellular polymeric substances isolated from Bacillus firmus and Bacillus sphaericus. We isolated bacterial outer structures (glycocalix and parietal polymers), such as exopolysaccharides (EPS) and capsular polysaccharides (CPS) and checked for their influence on calcite precipitation. CPS and EPS extracted from both B. firmus and B. sphaericus were able to mediate CaCO3 precipitation in vitro. X-ray microanalysis showed that in all cases the formed crystals were calcite. Scanning electron microscopy showed that the shape of the crystals depended on the fractions utilized. These results suggest the possibility that biochemical composition of CPS or EPS influences the resulting morphology of CaCO3. There were no precipitates in the blank samples. CPS and EPS comprised of proteins and glycoproteins. Positive alcian blue staining also reveals acidic polysaccharides in CPS and EPS fractions. Proteins with molecular masses of 25-40 kDa and 70 kDa in the CPS fraction were highly expressed in the presence of calcium oxalate. This high level of synthesis could be related to the binding of calcium ions and carbonate deposition.

  16. 77 FR 3459 - Cancellation of the Environmental Impact Statement for the Mountaineer Commercial Scale Carbon...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-01-24

    ... Cancellation of the Environmental Impact Statement for the Mountaineer Commercial Scale Carbon Capture and... ] (NEPA) for the Mountaineer Commercial Scale Carbon Capture and Storage (CCS) Project in Mason County, WV... Commercial Scale Carbon Capture and Storage Project (DOE/EIS-0445D) for public review and comment on March...

  17. Shrinkage Cracking: A mechanism for self-sustaining carbon mineralization reactions in olivine rocks

    NASA Astrophysics Data System (ADS)

    Zhu, W.; Fusseis, F.; Lisabeth, H. P.; Xing, T.; Xiao, X.; De Andrade, V. J. D.; Karato, S. I.

    2015-12-01

    The hydration and carbonation of olivine results in an up to ~44% increase in solid molar volume, which may choke off of fluid supply and passivate reactive surfaces, thus preventing further carbonation reactions. The carbonation of olivine has ben studied extensively in the laboratory. To date, observations from these experimental studies indicate that carbonation reaction rates generally decrease with time and the extent of carbonation is limited in olivine rocks. Field studies, however, show that 100% hydration and carbonation occur naturally in ultramafic rocks. The disagreement between the laboratory results under controlled conditions and the field observations underlines the lack of understanding of the mechanisms responsible for the self-sustaining carbonation interaction in nature. We developed a state-of-the-art pressurized hydrothermal cell that is transparent to X-rays to characterize the real-time evolution of pore geometry during fluid-rock interaction using in-situ synchrotron-based X-ray microtomography. Through a time series of high-resolution 3-dimensional images, we document the microstructural evolution of a porous olivine aggregate reacting with a sodium bicarbonate solution at elevated pressure and temperature conditions. We observed porosity increases, near constant rate of crystal growth, and pervasive reaction-induced fractures. Based on the nanometer scale tomography data, we propose that shrinkage cracking is the mechanism responsible for producing new reactive surface and keep the carbonation reaction self-sustaining in our experiment. Shrinkage cracks are commonly observed in drying mud ponds, cooling lava flows and ice wedge fields. Stretching of a contracting surface bonded to a substrate of nearly constant dimensions leads to a stress buildup in the surface layer. When the stress exceeds the tensile strength, polygonal cracks develop in the surface layer. In our experiments, the stretching mismatch between the surface and interior of

  18. Evidence for passive mineral carbonation from carbon isotope geochemistry of interstitial air in mine wastes from the Dumont Nickel Project (Abitibi, Quebec).

    NASA Astrophysics Data System (ADS)

    Gras, A.; Beaudoin, G.; Molson, J. W. H.; Plante, B.; Lemieux, J. M.; Kandji, E. H. B.

    2014-12-01

    Natural weathering of ultramafic rocks in mine tailings allows the sequestration of atmospheric CO2 through the formation of magnesium carbonates. The Dumont Nickel Project (DNP) is being studied to estimate the CO2 sequestration potential of future mining residues and to evaluate the impact of mineral carbonation on the quality of mine waste drainage water. For this purpose, experimental cells were built and instrumented in 2011. The first was constructed using milling waste and the second with mining waste. Laboratory characterization of residues and field observations will be combined to propose a quantitative model of mineral carbonation and metal leaching. A decrease of CO2 concentration in the mining waste cell, from atmospheric concentrations (~390 ppmv) near the surface of the cell to ~100 ppmv near the bottom, reflects active CO2 consumption by the residues. This cell contains mining waste with a large grain size distribution ranging from blocks (<40cm) to silt-size grains. Magnesium-rich minerals such as lizardite, chrysotile and brucite are the major minerals in the residues. Mineralogical analyses (XRD, SEM and EPMA) reveal precipitation of brugnatellite and hydromagnesite, with a lamellar texture on the surface of serpentine grains. In order to better identify the different processes involved in carbonation, the carbon isotopic composition of the interstitial gases was analysed in-situ with a WS-CRDS instrument. An increase of d13C(air) from -8‰ to ~2 ‰ is correlated with the decrease in CO2 concentration within the cell, and can be explained by dissolution of atmospheric CO2 in interstitial water (Dco2-DIC 11‰) in the DNP mining residues. As gas advection is slow, CO2 supply driven by diffusion is the limiting step in the experimental cell. CO2 dissolution in interstitial water under this limited CO2 supply condition enriches 13C in residual CO2 in interstitial air. Optimized mineral carbonation reactions in DNP mining waste will require an

  19. Carbon and sulfur isotopic signatures of ancient life and environment at the microbial scale: Neoarchean shales and carbonates.

    PubMed

    Williford, K H; Ushikubo, T; Lepot, K; Kitajima, K; Hallmann, C; Spicuzza, M J; Kozdon, R; Eigenbrode, J L; Summons, R E; Valley, J W

    2016-03-01

    An approach to coordinated, spatially resolved, in situ carbon isotope analysis of organic matter and carbonate minerals, and sulfur three- and four-isotope analysis of pyrite with an unprecedented combination of spatial resolution, precision, and accuracy is described. Organic matter and pyrite from eleven rock samples of Neoarchean drill core express nearly the entire range of δ(13) C, δ(34) S, Δ(33) S, and Δ(36) S known from the geologic record, commonly in correlation with morphology, mineralogy, and elemental composition. A new analytical approach (including a set of organic calibration standards) to account for a strong correlation between H/C and instrumental bias in SIMS δ(13) C measurement of organic matter is identified. Small (2-3 μm) organic domains in carbonate matrices are analyzed with sub-permil accuracy and precision. Separate 20- to 50-μm domains of kerogen in a single ~0.5 cm(3) sample of the ~2.7 Ga Tumbiana Formation have δ(13) C = -52.3 ± 0.1‰ and -34.4 ± 0.1‰, likely preserving distinct signatures of methanotrophy and photoautotrophy. Pyrobitumen in the ~2.6 Ga Jeerinah Formation and the ~2.5 Ga Mount McRae Shale is systematically (13) C-enriched relative to co-occurring kerogen, and associations with uraniferous mineral grains suggest radiolytic alteration. A large range in sulfur isotopic compositions (including higher Δ(33) S and more extreme spatial gradients in Δ(33) S and Δ(36) S than any previously reported) are observed in correlation with morphology and associated mineralogy. Changing systematics of δ(34) S, Δ(33) S, and Δ(36) S, previously investigated at the millimeter to centimeter scale using bulk analysis, are shown to occur at the micrometer scale of individual pyrite grains. These results support the emerging view that the dampened signature of mass-independent sulfur isotope fractionation (S-MIF) associated with the Mesoarchean continued into the early Neoarchean, and that the connections

  20. Degradation of flubendiamide as affected by elevated CO2, temperature, and carbon mineralization rate in soil.

    PubMed

    Mukherjee, Irani; Das, Shaon Kumar; Kumar, Aman

    2016-10-01

    An experiment was conducted under three levels of atmospheric CO2 [ambient (398 ± 10 μmol mol(-1)), elevated (570 ± 10 μmol mol(-1)) and open condition], three levels of temperature (4, 25, and 40 °C) to study the degradation pattern of flubendiamide in soil and also carbon mineralization in soil. Results of this study revealed that flubendiamide was found to persist longer under outdoor condition (T1/2, 177.0 and 181.1 days) than ambient (T1/2, 168.4 and 172.3 days) and elevated condition (T1/2, 159.3 and 155.3 days) at 1 and 10 μg g(-1) fortification level, respectively. Results also revealed that flubendiamide dissipated faster at 40 °C (T1/2, 189.4 days) than 25 °C (T1/2, 225.3 days). Slower dissipation was recorded at 4 °C (T1/2, 326.3 days). Thus, increased CO2 levels and temperature following global warming might adversely affect flubendiamide degradation in soil. Laboratory study on microbial biomass carbon (MBC) and carbon mineralization (Cmin) in soil revealed that in des-iodo flubendiamide-treated soils, MBC significantly increased up to 45 days and then decreased. Flubendiamide-treated soil showed a non-significantly decreasing trend of soil MBC with time up to the 15th day of incubation and after 15 days significantly decreased up to 90 days of incubation. In des-iodo flubendiamide-treated soil, the evolution of CO2 decreased up to 45 days, which was increased after 45 days up to 90 days. In flubendiamide-treated soil, CO2 evolution decreased up to 30 days and after 45 days, it increased up to 90 days. PMID:27430656

  1. Carbon Mineralization and Nitrogen Transformation During a Long Term Permafrost Incubation

    NASA Astrophysics Data System (ADS)

    Salmon, V. G.; Mack, M. C.; Schuur, E. A. G.

    2014-12-01

    As the limiting nutrient in warming high latitude ecosystems, nitrogen (N) is expected to play a key role in determining the future balance between permafrost carbon (C) losses and increased C sequestration by plants. During decomposition, nitrogen previously locked in soil organic matter is released into the soil solution in the form of dissolved organic molecules following depolymerization by extracellular enzymes. These dissolved organic forms of N can be consumed by the soil microbial community and incorporated in their biomass or mineralized if they are in excess of microbial demand. Once mineralized and released into the soil solutions, N can be lost from the soil system via denitrification. In well drained, low N tussock tundra, however, this pathway is unlikely. Dissolved inorganic N (DIN) and dissolved organic N (DON) are both biologically available to arctic plants. Understanding how the size of these pools changes with depth and continuing decomposition is therefore crucial to projecting the C balance of high latitude systems in a warmer future. N transformations associated with decomposition may differ greatly in surface soils, where a large labile C pool is present and soil has a high C:N ratio, versus deep soils that have a relatively small labile C pool and a lower C:N ratio. In this experiment, the relationship between N availability and C release from permafrost soils was addressed with a 225 day soil incubation performed at 15°C. Seven soil cores were collected from undisturbed, well drained tussock tundra and were partitioned into ten centimeter depth intervals to a depth of 80 cm. Carbon dioxide (CO2) fluxes were measured throughout the incubation period and were used to assess cumulative carbon losses and determine the size of the labile C pool. Destructive harvests at days 16,34,55,83, 143 and 225 were performed and pools of plant available DON and DIN were measured using 2M KCl extractions. At day 225 the microbial biomass N pool was also

  2. Incorporation of Np(V) and U(VI) in Carbonate and Sulfate Minerals Crystallized from Aqueous Solution

    SciTech Connect

    Balboni, Enrica; Morrison, Jessica M.; Wang, Zheming; Engelhard, Mark H.; Burns, Peter C.

    2015-02-15

    The neptunyl Np(V)O2 + and uranyl U(VI)O2 2+ ions are soluble in groundwater, although their interaction with minerals in the subsurface may impact their mobility. One mechanism for the immobilization of actinyl ions in the subsurface is coprecipitation in low-temperature minerals that form naturally, or that are induced to form as part of a remediation strategy. Important differences in the crystal-chemical behavior of the Np(V) neptunyl and U(VI) uranyl ions suggest their behavior towards incorporation into growing crystals may differ significantly. Using a selection of low temperature minerals synthesized in aqueous systems under ambient conditions, this study examines the factors that impact the structural incorporation of the Np(V) neptunyl and U(VI) uranyl ions in carbonate and sulfate minerals.

  3. Large-scale metal zoning in a late-Precambrian skarn-type mineralization, Wadi Kid, SE Sinai, Egypt

    NASA Astrophysics Data System (ADS)

    Helmy, H. M.; Shalaby, I. M.; Abdel Rahman, H. B.

    2014-02-01

    A Precambrian skarn-type mineralization is recently discovered in the Wadi Kid area in southeast Sinai, Egypt. Two sulfide ore types define large scale metal zoning; Cu-Zn-Co in calc-silicate rocks and Zn-Pb-As-Ag in metapelites. The sulfides and host rocks underwent amphibolite facies metamorphism (2.1-4.2 kbar and 500-620 °C). Dating by the chemical Th-U-total Pb isochrone method yields an Th-Pb isochrone age of 660 ± 25 Ma for metamorphic monazite from metapelites. Overall structural and textural relationships of silicate and sulfide minerals favor syn-tectonic formation during granitoids emplacement in a continental margin setting. Large-scale metal zoning reflects variable distances from the causative pluton(s). The Wadi Kid area is highly prospective for Cu, Zn, Pb and Ag mineralization.

  4. Roles of larval sea urchin spicule SM50 domains in organic matrix self-assembly and calcium carbonate mineralization.

    PubMed

    Rao, Ashit; Seto, Jong; Berg, John K; Kreft, Stefan G; Scheffner, Martin; Cölfen, Helmut

    2013-08-01

    The larval spicule matrix protein SM50 is the most abundant occluded matrix protein present in the mineralized larval sea urchin spicule. Recent evidence implicates SM50 in the stabilization of amorphous calcium carbonate (ACC). Here, we investigate the molecular interactions of SM50 and CaCO3 by investigating the function of three major domains of SM50 as small ubiquitin-like modifier (SUMO) fusion proteins - a C-type lectin domain (CTL), a glycine rich region (GRR) and a proline rich region (PRR). Under various mineralization conditions, we find that SUMO-CTL is monomeric and influences CaCO3 mineralization, SUMO-GRR aggregates into large protein superstructures and SUMO-PRR modifies the early CaCO3 mineralization stages as well as growth. The combination of these mineralization and self-assembly properties of the major domains synergistically enable the full-length SM50 to fulfill functions of constructing the organic spicule matrix as well as performing necessary mineralization activities such as Ca(2+) ion recruitment and organization to allow for proper growth and development of the mineralized larval sea urchin spicule.

  5. ATOMIC-LEVEL MODELING OF CO2 DISPOSAL AS A CARBONATE MINERAL: A SYNERGETIC APPROACH TO OPTIMIZING REACTION PROCESS DESIGN

    SciTech Connect

    A.V.G. Chizmeshya; M.J. McKelvy; J.B. Adams

    2001-11-01

    Fossil fuels, especially coal, can support the energy demands of the world for centuries to come, if the environmental problems associated with CO{sub 2} emissions can be overcome. Permanent and safe methods for CO{sub 2} capture and disposal/storage need to be developed. Mineralization of stationary-source CO{sub 2} emissions as carbonates can provide such safe capture and long-term sequestration. Mg-rich lamellar hydroxide mineral carbonation is a leading process candidate, which generates the stable naturally occurring mineral magnesite (MgCO{sub 3}) and water. Key to process cost and viability are the carbonation reaction rate and its degree of completion. This process, which involves simultaneous dehydroxylation and carbonation is very promising, but far from optimized. In order to optimize the dehydroxylation/carbonation process, an atomic-level understanding of the mechanisms involved is needed. In this investigation Mg(OH){sub 2} was selected as a model Mg-rich lamellar hydrocide carbonation feedstock material due to its chemical and structural simplicity. Since Mg(OH){sub 2} dehydroxylation is intimately associated with the carbonation process, its mechanisms are also of direct interest in understanding and optimizing the process. The aim of the current innovative concepts project is to develop a specialized advanced computational methodology to complement the ongoing experimental inquiry of the atomic level processes involved in CO{sub 2} mineral sequestration. The ultimate goal is to integrate the insights provided by detailed predictive simulations with the data obtained from optical microscopy, FESEM, ion beam analysis, SIMS, TGA, Raman, XRD, and C and H elemental analysis. The modeling studies are specifically designed to enhance the synergism with, and complement the analysis of, existing mineral-CO{sub 2} reaction process studies being carried out under DOE UCR Grant DE-FG2698-FT40112. Direct contact between the simulations and the experimental

  6. DRIFTS Sensor: Soil Carbon Validation at Large Scale (Pantelleria, Italy)

    PubMed Central

    Saiano, Filippo; Oddo, Giacomo; Scalenghe, Riccardo; La Mantia, Tommaso; Ajmone-Marsan, Franco

    2013-01-01

    A fast and accurate measurement of soil carbon is needed in current scientific issues. Today there are many sensors suitable for these purposes, but choosing the appropriate sensor depends on the spatial scale at which the studies are conducted. There are few detailed studies that validate these types of measures allowing their immediate use. Here it is validated the quick use of a sensor in execution at Pantelleria, chosen for size, use and variability of the parameter measured, to give an operational tool for carbon stocks studies. The DRIFT sensor used here has been validated in the first 60 cm of the soil of the whole island, and it has shown predictivity higher than 90%. PMID:23624691

  7. Data compilation, synthesis, and calculations used for organic-carbon storage and inventory estimates for mineral soils of the Mississippi River Basin

    USGS Publications Warehouse

    Buell, Gary R.; Markewich, Helaine W.

    2004-01-01

    U.S. Geological Survey investigations of environmental controls on carbon cycling in soils and sediments of the Mississippi River Basin (MRB), an area of 3.3 x 106 square kilometers (km2), have produced an assessment tool for estimating the storage and inventory of soil organic carbon (SOC) by using soil-characterization data from Federal, State, academic, and literature sources. The methodology is based on the linkage of site-specific SOC data (pedon data) to the soil-association map units of the U.S. Department of Agriculture State Soil Geographic (STATSGO) and Soil Survey Geographic (SSURGO) digital soil databases in a geographic information system. The collective pedon database assembled from individual sources presently contains 7,321 pedon records representing 2,581 soil series. SOC storage, in kilograms per square meter (kg/m2), is calculated for each pedon at standard depth intervals from 0 to 10, 10 to 20, 20 to 50, and 50 to 100 centimeters. The site-specific storage estimates are then regionalized to produce national-scale (STATSGO) and county-scale (SSURGO) maps of SOC to a specified depth. Based on this methodology, the mean SOC storage for the top meter of mineral soil in the MRB is approximately 10 kg/m2, and the total inventory is approximately 32.3 Pg (1 petagram = 109 metric tons). This inventory is from 2.5 to 3 percent of the estimated global mineral SOC pool.

  8. Ground cover rice production systems increase soil carbon and nitrogen stocks at regional scale

    NASA Astrophysics Data System (ADS)

    Liu, M.; Dannenmann, M.; Lin, S.; Saiz, G.; Yan, G.; Yao, Z.; Pelster, D. E.; Tao, H.; Sippel, S.; Tao, Y.; Zhang, Y.; Zheng, X.; Zuo, Q.; Butterbach-Bahl, K.

    2015-08-01

    Rice production is increasingly limited by water scarcity. Covering paddy rice soils with films (so-called ground cover rice production system: GCRPS) can significantly reduce water demand as well as overcome temperature limitations at the beginning of the growing season, which results in greater grain yields in relatively cold regions and also in those suffering from seasonal water shortages. However, it has been speculated that both increased soil aeration and temperature under GCRPS result in lower soil organic carbon and nitrogen stocks. Here we report on a regional-scale experiment conducted in Shiyan, a typical rice-producing mountainous area of China. We sampled paired adjacent paddy and GCRPS fields at 49 representative sites. Measured parameters included soil carbon (C) and nitrogen (N) stocks (to 1 m depth), soil physical and chemical properties, δ15N composition of plants and soils, potential C mineralization rates, and soil organic carbon (SOC) fractions at all sampling sites. Root biomass was also quantified at one intensively monitored site. The study showed that: (1) GCRPS increased SOC and N stocks 5-20 years following conversion from traditional paddy systems; (2) there were no differences between GCRPS and paddy systems in soil physical and chemical properties for the various soil depths, with the exception of soil bulk density; (3) GCRPS increased above-ground and root biomass in all soil layers down to a 40 cm depth; (4) δ15N values were lower in soils and plant leaves indicating lower NH3 volatilization losses from GCRPS than in paddy systems; and (5) GCRPS had lower C mineralization potential than that observed in paddy systems over a 200-day incubation period. Our results suggest that GCRPS is an innovative production technique that not only increases rice yields using less irrigation water, but that it also increases SOC and N stocks.

  9. Novel approaches to understanding carbon redistribution at multiple scales

    NASA Astrophysics Data System (ADS)

    Dungait, Jennifer; Beniston, Joshua; Lal, Rattan; Horrocks, Claire; Collins, Adrian; Mariappen, Sankar; Quine, Timothy

    2014-05-01

    Established biogeochemical techniques are used to trace organic inputs typically derived directly or indirectly from plants into soils, sediments and water using lipid biomarkers. Recently, advances in bulk and compound specific stable 13C isotope analyses have provided novel ways of exploring the source and residence times of organic matter in soils using the natural abundance stable 13C isotope signature of C3 and C4 plant end member values. However, the application of biogeochemical source tracing technologies at the molecular level at field to catchment scales has been slow to develop because of perceived problems with dilution of molecular-scale signals. This paper describes the results of recent experiments in natural and agricultural environments in the UK (Collins et al., 2013; Dungait et al., 2013) and United States (Beniston et al., submitted) that have successfully applied new tracing techniques using stable 13C isotope and complementary approaches to explore the transport of sediment-bound organic carbon at a range of scales from the small plot (m2) to field (ha) and small catchment (10's ha). References Beniston et al (submitted) The effects of crop residue removal on soil erosion and macronutrient dynamics on soils under no till for 42 years. Biogeosciences Collins et al (2013) Catchment source contributions to the sediment-bound organic matter degrading salmonid spawning gravels in a lowland river, southern England. Science of the Total Environment 456-457, 181-195. Dungait et al (2013) Microbial responses to the erosional redistribution of soil organic carbon in arable fields. Soil Biology and Biochemistry 60, 195-201. Puttock et al (2012) Stable carbon isotope analysis of fluvial sediment fluxes over two contrasting C4-C3 semi-arid vegetation transitions. Rapid Communications in Mass Spectrometry 26, 2386-2392.

  10. Variations in the patterns of soil organic carbon mineralization and microbial communities in response to exogenous application of rice straw and calcium carbonate.

    PubMed

    Feng, Shuzhen; Huang, Yuan; Ge, Yunhui; Su, Yirong; Xu, Xinwen; Wang, Yongdong; He, Xunyang

    2016-11-15

    The addition of exogenous inorganic carbon (CaCO3) and organic carbon has an important influence on soil organic carbon (SOC) mineralization in karst soil, but the microbial mechanisms underlying the SOC priming effect are poorly understood. We conducted a 100-day incubation experiment involving four treatments of the calcareous soil in southwestern China's karst region: control, (14)C-labeled rice straw addition, (14)C-labeled CaCO3 addition, and a combination of (14)C-labeled rice straw and CaCO3. Changes in soil microbial communities were characterized using denaturing gradient gel electrophoresis with polymerase chain reaction (PCR-DGGE) and real-time quantitative PCR (q-PCR). Both (14)C-rice straw and Ca(14)CO3 addition stimulated SOC mineralization, suggesting that organic and inorganic C affected SOC stability. Addition of straw alone had no significant effect on bacterial diversity; however, when the straw was added in combination with calcium carbonate, it had an inhibitory effect on bacterial and fungal diversity. At the beginning of the experimental period, exogenous additives increased bacterial abundance, although at the end of the 100-day incubation bacterial community abundance had gradually declined. Incubation time, exogenous input, and their interaction significantly affected SOC mineralization (in terms of priming and the cumulative amount of mineralization), microbial biomass carbon (MBC), and microbial community abundance and diversity. Moreover, the key factors influencing SOC mineralization were MBC, bacterial diversity, and soil pH. Overall, these findings support the view that inorganic C is involved in soil C turnover with the participation of soil microbial communities, promoting soil C cycling in the karst region.

  11. Variations in the patterns of soil organic carbon mineralization and microbial communities in response to exogenous application of rice straw and calcium carbonate.

    PubMed

    Feng, Shuzhen; Huang, Yuan; Ge, Yunhui; Su, Yirong; Xu, Xinwen; Wang, Yongdong; He, Xunyang

    2016-11-15

    The addition of exogenous inorganic carbon (CaCO3) and organic carbon has an important influence on soil organic carbon (SOC) mineralization in karst soil, but the microbial mechanisms underlying the SOC priming effect are poorly understood. We conducted a 100-day incubation experiment involving four treatments of the calcareous soil in southwestern China's karst region: control, (14)C-labeled rice straw addition, (14)C-labeled CaCO3 addition, and a combination of (14)C-labeled rice straw and CaCO3. Changes in soil microbial communities were characterized using denaturing gradient gel electrophoresis with polymerase chain reaction (PCR-DGGE) and real-time quantitative PCR (q-PCR). Both (14)C-rice straw and Ca(14)CO3 addition stimulated SOC mineralization, suggesting that organic and inorganic C affected SOC stability. Addition of straw alone had no significant effect on bacterial diversity; however, when the straw was added in combination with calcium carbonate, it had an inhibitory effect on bacterial and fungal diversity. At the beginning of the experimental period, exogenous additives increased bacterial abundance, although at the end of the 100-day incubation bacterial community abundance had gradually declined. Incubation time, exogenous input, and their interaction significantly affected SOC mineralization (in terms of priming and the cumulative amount of mineralization), microbial biomass carbon (MBC), and microbial community abundance and diversity. Moreover, the key factors influencing SOC mineralization were MBC, bacterial diversity, and soil pH. Overall, these findings support the view that inorganic C is involved in soil C turnover with the participation of soil microbial communities, promoting soil C cycling in the karst region. PMID:27401276

  12. Development of poly(aspartic acid-co-malic acid) composites for calcium carbonate and sulphate scale inhibition.

    PubMed

    Mithil Kumar, N; Gupta, Sanjay Kumar; Jagadeesh, Dani; Kanny, K; Bux, F

    2015-01-01

    Polyaspartic acid (PSI) is suitable for the inhibition of inorganic scale deposition. To enhance its scale inhibition efficiency, PSI was modified by reacting aspartic acid with malic acid (MA) using thermal polycondensation polymerization. This reaction resulted in poly(aspartic acid-co-malic acid) (PSI-co-MA) dual polymer. The structural, chemical and thermal properties of the dual polymers were analysed by using scanning electron microscopy, Fourier transform infrared spectroscopy, X-ray diffraction, differential scanning calorimetry and gel permeation chromatography. The effectiveness of six different molar ratios of PSI-co-MA dual polymer for calcium carbonate and calcium sulphate scale inhibition at laboratory scale batch experiments was evaluated with synthetic brine solution at selected doses of polymer at 65-70°C by the static scale test method. The performance of PSI-co-MA dual polymer for the inhibition of calcium carbonate and calcium sulphate precipitation was compared with that of a PSI single polymer. The PSI-co-MA exhibited excellent ability to control inorganic minerals, with approximately 85.36% calcium carbonate inhibition and 100% calcium sulphate inhibition at a level of 10 mg/L PSI-co-MA, respectively. Therefore, it may be reasonably concluded that PSI-co-MA is a highly effective scale inhibitor for cooling water treatment applications.

  13. Large fluxes and rapid turnover of mineral-associated carbon across topographic gradients in a humid tropical forest: insights from paired 14C analysis

    NASA Astrophysics Data System (ADS)

    Hall, S. J.; McNicol, G.; Natake, T.; Silver, W. L.

    2015-01-01

    It has been proposed that the large soil carbon (C) stocks of humid tropical forests result predominantly from C stabilization by reactive minerals, whereas oxygen (O2) limitation of decomposition has received much less attention. We examined the importance of these factors in explaining patterns of C stocks and turnover in the Luquillo Experimental Forest, Puerto Rico, using radiocarbon (14C) measurements of contemporary and archived samples. Samples from ridge, slope, and valley positions spanned three soil orders (Ultisol, Oxisol, Inceptisol) representative of humid tropical forests, and differed in texture, reactive metal content, O2 availability, and root biomass. Mineral-associated C comprised the large majority (87 ± 2%, n = 30) of total soil C. Turnover of most mineral-associated C (74 ± 4%) was rapid (9 to 29 years, mean and SE 20 ± 2 years) in 25 of 30 soil samples across surface horizons (0-10 and 10-20 cm depths) and all topographic positions, independent of variation in reactive metal concentrations and clay content. Passive C with centennial - millennial turnover was much less abundant (26%), even at 10-20 cm depths. Carbon turnover times and concentrations significantly increased with concentrations of reduced iron (Fe(II)) across all samples, suggesting that O2 availability may have limited the decomposition of mineral associated C over decadal scales. Steady-state inputs of mineral-associated C were similar among the three topographic positions, and could represent 10-30% of annual litterfall production (estimated by doubling aboveground litterfall). Observed trends in mineral-associated Δ14C over time could not be fit using the single pool model used in many other studies, which generated contradictory relationships between turnover and Δ14C as compared with a more realistic constrained two-pool model. The large C fluxes in surface and near-surface soils implied by our data suggest that other studies using single-pool Δ14C models of mineral

  14. Large fluxes and rapid turnover of mineral-associated carbon across topographic gradients in a humid tropical forest: insights from paired 14C analysis

    DOE PAGESBeta

    Hall, S. J.; McNicol, G.; Natake, T.; Silver, W. L.

    2015-01-16

    It has been proposed that the large soil carbon (C) stocks of humid tropical forests result predominantly from C stabilization by reactive minerals, whereas oxygen (O2) limitation of decomposition has received much less attention. We examined the importance of these factors in explaining patterns of C stocks and turnover in the Luquillo Experimental Forest, Puerto Rico, using radiocarbon (14C) measurements of contemporary and archived samples. Samples from ridge, slope, and valley positions spanned three soil orders (Ultisol, Oxisol, Inceptisol) representative of humid tropical forests, and differed in texture, reactive metal content, O2 availability, and root biomass. Mineral-associated C comprised themore » large majority (87 ± 2%, n = 30) of total soil C. Turnover of most mineral-associated C (74 ± 4%) was rapid (9 to 29 years, mean and SE 20 ± 2 years) in 25 of 30 soil samples across surface horizons (0–10 and 10–20 cm depths) and all topographic positions, independent of variation in reactive metal concentrations and clay content. Passive C with centennial – millennial turnover was much less abundant (26%), even at 10–20 cm depths. Carbon turnover times and concentrations significantly increased with concentrations of reduced iron (Fe(II)) across all samples, suggesting that O2 availability may have limited the decomposition of mineral associated C over decadal scales. Steady-state inputs of mineral-associated C were similar among the three topographic positions, and could represent 10–30% of annual litterfall production (estimated by doubling aboveground litterfall). Observed trends in mineral-associated Δ14C over time could not be fit using the single pool model used in many other studies, which generated contradictory relationships between turnover and Δ14C as compared with a more realistic constrained two-pool model. The large C fluxes in surface and near-surface soils implied by our data suggest that other studies using single-pool Δ14C

  15. Microbes residing in young organic rich Alaskan soils contain older carbon than those residing in old mineral high Arctic soils

    NASA Astrophysics Data System (ADS)

    Ziolkowski, L. A.; Slater, G. F.; Onstott, T. C.; Whyte, L.; Townsend-Small, A.

    2013-12-01

    Arctic soils range from very organic rich to low carbon and mineral-dominated soils. At present, we do not yet fully understand if all carbon in the Arctic is equally vulnerable to mineralization in a warmer climate. Many studies have demonstrated that ancient carbon is respired when permafrost has thawed, yet our understanding of the active layer and permafrost carbon dynamics is still emerging. In an effort to remedy this disconnect between our knowledge of surface fluxes and below ground processes, we used radiocarbon to examine the microbial carbon dynamics in soil cores from organic rich soils near Barrow, Alaska and mineral soils from the Canadian high Arctic. Specifically, we compared the microbial community using lipid biomarkers, the inputs of carbon using n-alkanes and measured the 14C of both the bulk organic carbon and of the microbial lipids. In theory, the microbial lipids (phospholipid fatty acids, PLFA) represent the viable microbial community, as these lipids are hydrolyzed quickly after cell death. Variations in the PLFA distributions suggested that different microbial communities inhabit organic rich Alaskan soils and those of the Canadian high Arctic. When the PLFA concentrations were converted to cellular concentration, they were within the same order of magnitude (1 to 5 x 108 cells/g dry soil) with slightly higher cell concentrations in the organic rich Alaskan soils. When these cellular concentrations were normalized to the organic carbon content, the Canadian high Arctic soils contained a greater proportion of microbes. Although bulk organic carbon 14C of Alaskan soils indicated more recent carbon inputs into the soil than the Canadian high Arctic soils, the 14C of the PLFA revealed the opposite. For corresponding depth horizons, microbes in Alaskan soils were consuming carbon 1000 to 1500 years older than those in the Canadian high Arctic. Differences between the 14C content of bulk organic carbon and the microbial lipids were much smaller

  16. Navier-Stokes analysis of scale effects on ablation in carbon-carbon rocket nozzles

    NASA Astrophysics Data System (ADS)

    Bianchi, D.; Nasuti, F.; Martelli, E.; Onofri, M.

    2012-01-01

    A study is conducted to predict carbon-carbon nozzle recession behavior in solid rocket motors (SRM) for wide variations of propellant formulations and motor operating conditions. The numerical model considers the solution of Reynolds averaged Navier-Stokes (RANS) equations in the nozzle, heterogeneous chemical reactions at the nozzle surface, variable transport and thermodynamic properties, and heat conduction in the nozzle material. Results show that the ablation rate is affected by the dimension of the nozzle as well as by the boundary layer thickness at the nozzle entrance. The combined effect of both scale and boundary layer thickness at the nozzle entrance is also analyzed.

  17. The distribution of secondary mineral phases along an eroding hillslope and its effect on carbon stabilization mechanisms and the fate of soil carbon fractions

    NASA Astrophysics Data System (ADS)

    Doetterl, Sebastian; Cornelis, Jean-Thomas; Opfergelt, Sophie; Boeckx, Pascal; Bodé, Samuel; Six, Johan; Van Oost, Kristof

    2014-05-01

    Soil redistribution processes can change soil carbon (C) dynamics drastically by moving carbon from high decomposition and re-sequestration environments at the eroding hillslope to low decomposition and burial at the depositional footslope and valley basin. This leads to not only spatially diverse soil carbon storage throughout the landscape, but also to qualitative changes of the transported carbon and the mineral phase. The interaction between those parameters and the effect on stabilization mechanisms for soil C are still a matter of debate. Here, we present an analysis that aims to clarify the bio/geo-chemical and mineralogical components involved in stabilizing C at various depths along an eroding cropped slope and how this affects the abundance of microbial derived carbon. We use the results of an incubation experiment combined with the abundance of amino sugars in different isolated soil C fractions as a tracer for the stability of the respective fraction. We applied further (i) a sequential extraction of the reactive soil phase using pyrophosphate, oxalate and dithionite-citrate-bicarbonate, and (ii) a qualitative analysis of the clay mineralogy, to analyze the changes in the mineral phase for the different isolated fractions along the slope transect. Our results emphasize the importance of physical protection within microaggregates to stabilize buried, chemically labile C. Our data further indicates that the stability of these aggregates is related to the presence of organo-mineral associations and poorly crystalline minerals. However, decreasing contents of these minerals with depth indicate a temporal limitation of this stabilization mechanism. Non-expandable clay minerals experience a relative enrichment at the depositional site while expandable clay minerals experience the same at the eroding site. These changes in clay mineralogy along the slope are partly responsible for the abundance of silt and clay associated C and the effectiveness of the clay

  18. Unique micro- and nano-scale mineralization pattern of human osteogenesis imperfecta type VI bone.

    PubMed

    Fratzl-Zelman, Nadja; Schmidt, Ingo; Roschger, Paul; Roschger, Andreas; Glorieux, Francis H; Klaushofer, Klaus; Wagermaier, Wolfgang; Rauch, Frank; Fratzl, Peter

    2015-04-01

    Osteogenesis imperfecta (OI) is a heterogeneous group of inheritable connective tissue disorders characterized by mutation in genes involved in collagen synthesis and leading to increased bone fragility, low bone mass, impaired bone material properties and abnormally high bone matrix mineralization. Recessive OI type VI is caused by mutation in SERPINF1 leading to a loss-of-function of pigment epithelium-derived factor (PEDF) a collagen-binding protein with potent antiangiogenic activity. Affected patients develop a severe OI phenotype with a striking histological characteristic, rare in other OI types, of an excess of osteoid tissue and prolonged mineralization lag time. To get insights into matrix mineralization, we evaluated biopsies from 9 affected children by quantitative and by high-resolution backscattered electron imaging and assessed bone mineralization density distribution. Thickness, shape and arrangement of mineral particles were measured in a subset of 4 patients by synchrotron small angle X-ray scattering. Typical calcium content in the bone matrix was found to be increased compared to controls, even exceeding values found previously in OI patients with collagen-gene mutations. A main characteristic however, is the coexistence of this highly mineralized bone matrix with seams showing abnormally low mineral content. Atypical collagen fibril organization was found in the perilacunar region of young osteocytes, suggesting a disturbance in the early steps of mineralization. These observations are consistent with the presence of a heterogeneous population of mineral particles with unusual size, shape and arrangement, especially in the region with lower mineral content. The majority of the particles in the highly mineralized bone areas were less disorganized, but smaller and more densely packed than in controls and in previously measured OI patients. These data suggest that the lack of PEDF impairs a proper osteoblast-osteocyte transition and consequently

  19. Exploration of vertical scaling limit in carbon nanotube transistors

    NASA Astrophysics Data System (ADS)

    Qiu, Chenguang; Zhang, Zhiyong; Yang, Yingjun; Xiao, Mengmeng; Ding, Li; Peng, Lian-Mao

    2016-05-01

    Top-gated carbon nanotube field-effect transistors (CNT FETs) were fabricated by using ultra-thin (4.5 nm or thinner) atomic-layer-deposition grown HfO2 as gate insulator, and shown to exhibit high gate efficiency, i.e., all examined (totally 76) devices present very low room temperature subthreshold swing with an averaged value of 64 mV/Dec, without observable carrier mobility degradation. The gate leakage of the CNT FET under fixed gate voltage is dependent not only on the thickness of HfO2 insulator, but also on the diameter of the CNT. The vertical scaling limit of CNT FETs is determined by gate leakage standard in ultra large scale integrated circuits. HfO2 film with effective oxide thickness of 1.2 nm can provide both excellent gate electrostatic controllability and small gate leakage for sub-5 nm FETs based on CNT with small diameter.

  20. Microbial and Mineral Controls on Soil Organic Carbon Decomposition: Testing the MEND Model with Data from Lab Incubations

    NASA Astrophysics Data System (ADS)

    Wang, G.; Jagadamma, S.; Steinweg, J. M.; Mayes, M. A.; Post, W. M.

    2012-12-01

    Microbes (including enzymes) and physical-chemical protection play important roles in controlling soil organic carbon (SOC) decomposition. The Microbial-ENzyme-mediated Decomposition (MEND) model was used to examine the dynamics of physically fractionated SOC pools in lab incubation experiments. The carbon pools in MEND consist of particulate, mineral-associated, dissolved organic carbon (POC, MOC, and DOC, respectively), microbial biomass, and associated exoenzymes. The following component carbon fluxes are described in MEND: POC and MOC decomposition, DOC uptake by microbes, adsorption and desorption of DOC, microbial growth and maintenance respiration, microbial mortality, and enzyme production and turnover. The kinetic parameters pertaining to these processes were determined based on the measured respiration processes and the a priori ranges/distributions of parameters. We attempted to demonstrate different dynamics of POC and MOC pools regulated by microbial-enzyme activities under different physical-chemical circumstances. Carbon pools and fluxes in the microbial-enzyme-mediated decomposition model

  1. NMMB/BSC-DUST: an online mineral dust atmospheric model from meso to global scales

    NASA Astrophysics Data System (ADS)

    Haustein, K.; Pérez, C.; Jorba, O.; Baldasano, J. M.; Janjic, Z.; Black, T.; Nickovic, S.

    2009-04-01

    While mineral dust distribution and effects are important at global scales, they strongly depend on dust emissions that are controlled on small spatial and temporal scales. Most global dust models use prescribed wind fields provided by meteorological centers (e.g., NCEP and ECMWF) and their spatial resolution is currently never better than about 1°×1°. Regional dust models offer substantially higher resolution (10-20 km) and are typically coupled with weather forecast models that simulate processes that GCMs either cannot resolve or can resolve only poorly. These include internal circulation features such as the low-level nocturnal jet which is a crucial feature for dust emission in several dust ‘hot spot' sources in North Africa. Based on our modeling experience with the BSC-DREAM regional forecast model (http://www.bsc.es/projects/earthscience/DREAM/) we are currently implementing an improved mineral dust model [Pérez et al., 2008] coupled online with the new global/regional NMMB atmospheric model under development in NOAA/NCEP/EMC [Janjic, 2005]. The NMMB is an evolution of the operational WRF-NMME extending from meso to global scales. The NMMB will become the next-generation NCEP model for operational weather forecast in 2010. The corresponding unified non-hydrostatic dynamical core ranges from meso to global scale allowing regional and global simulations. It has got an add-on non-hydrostatic module and it is based on the Arakawa B-grid and hybrid pressure-sigma vertical coordinates. NMMB is fully embedded into the Earth System Modeling Framework (ESMF), treating dynamics and physics separately and coupling them easily within the ESMF structure. Our main goal is to provide global dust forecasts up to 7 days at mesoscale resolutions. New features of the model include a physically-based dust emission scheme after White [1979], Iversen and White [1982] and Marticorena and Bergametti [1995] that takes the effects of saltation and sandblasting into account

  2. Tufa in Northern England: depositional facies, carbonate mineral fabrics, and role of biomineralization

    NASA Astrophysics Data System (ADS)

    Manzo, E.; Mawson, M.; Perri, E.; Tucker, M. E.

    2009-04-01

    soil hereabouts, and are gradually being washed down slope. Pisoids vary in size and shape, ranging from rods to sub-spherical forms, up to several cm long or a cm or more in diameter. The external surface is a smooth dull surface of a pale grey-buff colour; the nucleus may be a plant fragment, tufa intraclast or rock fragment. Microfacies Teesdale tufa is characterized by three microfacies all contributing to a basic stromatolitic or laminated microfabric: dendrolite, dense micrite and palisades of sparite. Laminae consist of an irregular alternation of the three microfacies, which vary in abundance within the main depositional facies. Dendrolitic layers are characterized of mineralized, upward-branching cyanobacterial filaments, forming bush-like fans. Coarse sparitic layers consist of palisades of bladed calcite spar characterized by rhombohedral terminations. Micritic layers consist of dark-brown dense laminae with some clotted fabric, composed of dark micritic crystals. In thin-section molds of moss stems are often preserved by a sparitic layer that formed a coating before decay of the moss organic tissues. Cavities are abundant in moss tufa and crusts. They are often empty or in some case filled by detrital particles. Pisoids under the microscope show a cortex characterized by a concentric structure consisting mainly dense micritic layers alternating with sporadic sparitic and/or dendrolitic layers. Calcified cyanobacterial filaments or their molds are very evident in the dendrolitic laminae, but also occur in the other microfacies, being incorporated in both the sparite macro-crystals and the micritic layers. Nanofacies of minerals The mineral composition of the aut