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Search indexed NASA NTRS and DOE OSTI research on propulsion, heat transfer, battery materials and energy systems. Follow report and document links to the original sources.

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At least 667 records · Page 37
All sourcesNASA NTRSDOE OSTI
DOE OSTI2015

An active atmospheric methane sink in high Arctic mineral cryosols

The transition of Arctic carbon-rich cryosols into methane (CH₄)-emitting wetlands due to global warming is a rising concern. However, the spatially predominant mineral cryosols and their CH₄ emission potential are poorly understood. Fluxes measured in situ and estimated under laboratory conditions coupled with -omics analysis indicate (1) mineral cryosols in the Canadian high Arctic contain atmospheric CH₄-oxidizing bacteria; (2) the atmospheric CH⁺ uptake flux increases with ground temperature; and, as a result, (3) the atmospheric CH₄ sink strength will increase by a factor of 5-30 as the Arctic warms by 5-15 °C over a century. We demonstrated that acidic mineral cryosols have previously unrecognized potential of negative CH₄ feedback.

54 ENVIRONMENTAL SCIENCES↗
DOE OSTI2017

3D calcite heterostructures for dynamic and deformable mineralized matrices

Scales are rooted in soft tissues, and are regenerated by specialized cells. The realization of dynamic synthetic analogues with inorganic materials has been a significant challenge, because the abiological regeneration sites that could yield deterministic growth behavior are hard to form. Here we overcome this fundamental hurdle by constructing a mutable and deformable array of three-dimensional calcite heterostructures that are partially locked in silicone. Individual calcite crystals exhibit asymmetrical dumbbell shapes and are prepared by a parallel tectonic approach under ambient conditions. Furthermore, the silicone matrix immobilizes the epitaxial nucleation sites through self-templated cavities, which enables symmetry breaking in reaction dynamics and scalable manipulation of the mineral ensembles. With this platform, we devise several mineral-enabled dynamic surfaces and interfaces. For example, we show that the induced growth of minerals yields localized inorganic adhesion for biological tissue and reversible focal encapsulation for sensitive components in flexible electronics.

36 MATERIALS SCIENCE↗
DOE OSTI2023

Bioinspired mechanical mineralization of organogels

Mineralization is a long-lasting method commonly used by biological materials to selectively strengthen in response to site specific mechanical stress. Achieving a similar form of toughening in synthetic polymer composites remains challenging. In previous work, we developed methods to promote chemical reactions via the piezoelectrochemical effect with mechanical responses of inorganic, ZnO nanoparticles. Herein, we report a distinct example of a mechanically-mediated reaction in which the spherical ZnO nanoparticles react themselves leading to the formation of microrods composed of a Zn/S mineral inside an organogel. The microrods can be used to selectively create mineral deposits within the material resulting in the strengthening of the overall resulting composite.

59 BASIC BIOLOGICAL SCIENCES↗
DOE OSTI2017

Importance of interlayer H bonding structure to the stability of layered minerals

Layered (oxy) hydroxide minerals often possess out-of-plane hydrogen atoms that form hydrogen bonding networks which stabilize the layered structure. However, less is known about how the ordering of these bonds affects the structural stability and solubility of these minerals. Here, we report a new strategy that uses the focused electron beam to probe the effect of differences in hydrogen bonding networks on mineral solubility. In this regard, the dissolution behavior of boehmite (γ-AlOOH) and gibbsite (γ-Al(OH)3) were compared and contrasted in real time via liquid cell electron microscopy. Under identical such conditions, 2D-nanosheets of boehmite (γ-AlOOH) exfoliated from the bulk and then rapidly dissolved, whereas gibbsite was stable. Further, substitution of only 1% Fe(III) for Al(III) in the structure of boehmite inhibited delamination and dissolution. Factors such as pH, radiolytic species, and knock on damage were systematically studied and eliminated as proximal causes for boehmite dissolution. Instead, the creation of electron/hole pairs was considered to be the mechanism that drove dissolution. The widely disparate behaviors of boehmite, gibbsite, and Fe-doped boehmite are discussed in the context of differences in the OH bond strengths, hydrogen bonding networks, and the presence or absence of electron/hole recombination centers.

58 GEOSCIENCES↗
DOE OSTI2018

Carbohydrates protect protein against abiotic fragmentation by soil minerals

The degradation and turnover of soil organic matter is an important part of global carbon cycling and of particular importance with respect to attempts to predict the response of ecosystems to global climate change. Thus, it is important to mechanistically understand the processes by which organic matter can be degraded in the soil environment, including contact with reactive or catalytic mineral surfaces. We have characterized the outcome of the interaction of two minerals, birnessite and kaolinite, with two disaccharides, cellobiose and trehalose. These results show that birnessite reacts with and degrades the carbohydrates, while kaolinite does not. The reaction of disaccharides with birnessite produces Mn(II), indicating that degradation of the disaccharides is the result of their oxidation by birnessite. Furthermore, we find that both sugars can inhibit the degradation of a model protein by birnessite, demonstrating that the presence of one organic constituent can impact abiotic degradation of another. Therefore, both the reactivity of the mineral matrix and the presence of certain organic constituents influence the outcomes of abiotic degradation. These results suggest the possibility that microorganisms may be able to control the functionality of exoenzymes through the concomitant excretion of protective organic substances, such as those found in biofilms.

Reardon, Patrick N. (ORCID:0000000268580086)↗
DOE OSTI2021

Micro-continuum approach for mineral precipitation

Abstract Rates and extents of mineral precipitation in porous media are difficult to predict, in part because laboratory experiments are problematic. It is similarly challenging to implement numerical methods that model this process due to the need to dynamically evolve the interface of solid material. We developed a multiphase solver that implements a micro-continuum simulation approach based on the Darcy–Brinkman–Stokes equation to study mineral precipitation. We used the volume-of-fluid technique in sharp interface implementation to capture the propagation of the solid mineral surface. Additionally, we utilize an adaptive mesh refinement method to improve the resolution of near interface simulation domain dynamically. The developed solver was validated against both analytical solution and Arbitrary Lagrangian–Eulerian approach to ensure its accuracy on simulating the propagation of the solid interface. The precipitation of barite (BaSO 4 ) was chosen as a model system to test the solver using variety of simulation parameters: different geometrical constraints, flow conditions, reaction rate and ion diffusion. The growth of a single barite crystal was simulated to demonstrate the solver’s capability to capture the crystal face specific directional growth.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
DOE OSTI2025

Complex carbonate phases drive geologic CO2 mineralization

Abstract Geologic carbon sequestration in mafic and ultramafic reservoirs is a scalable strategy for carbon dioxide removal, offering permanent storage via mineralization as stable carbonates. However, there is limited information on the structure and composition of key mineralization endpoints during sequestration. Here, we unravel the atomic structure, composition, and nanoscale morphology of carbonates recovered from a field-scale demonstration of CO 2 mineralization in basalt. Using transmission electron microscopy, we mapped mineralogical variations from the initial to later stages of subsurface carbonate growth and identified a previously unknown cation-ordered ankerite phase that exerts a primary control over carbonation processes. This study has provided a new understanding of subsurface carbonation pathways which will impact the parameterization of predictive geochemical models for future sequestration efforts in basalt formations.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
DOE OSTI2026

Aperture and roughness govern iron oxide passivation in olivine fractures during carbon mineralization

Efficient carbon dioxide mineralization in silicate-rich formations depends on reaction rates within fracture networks, yet the role of fracture microstructure remains poorly constrained. We investigated how fracture aperture and surface roughness influence mineralization by reacting synthetic forsteritic olivine fractures with controlled apertures (0.5–1.6 millimeters) and roughness (6–16 micrometers) with supercritical carbon dioxide at 13.7 megapascals and 185 degrees Celsius. Optical microscopy and Raman spectroscopy showed that rougher fracture surfaces promoted iron oxide precipitation, which passivated olivine surfaces, limiting magnesium availability for carbonate formation while removing iron as a reactant. These effects were more pronounced in smaller-aperture fractures. A geochemical model incorporating surface topography and passivation reproduced the observed trends, confirming that increased roughness can reduce reactivity despite greater surface area. Our results demonstrate that fracture microstructure strongly influences iron oxide passivation and carbon dioxide mineralization, with important implications for predicting long-term performance of engineered carbon dioxide storage systems.

54 ENVIRONMENTAL SCIENCES↗
DOE OSTI2016

Direct experimental evidence for differing reactivity alterations of minerals following irradiation. The case of calcite and quartz

Concrete, used in the construction of nuclear power plants (NPPs), may be exposed to radiation emanating from the reactor core. Until recently, concrete has been assumed immune to radiation exposure. Direct evidence acquired on Ar+ -ion irradiated calcite and quartz indicates, on the contrary, that, such minerals, which constitute aggregates in concrete, may be significantly altered by irradiation. More specifically, while quartz undergoes disordering of its atomic structure resulting in a near complete lack of periodicity, calcite only experiences random rotations, and distortions of its carbonate groups. As a result, irradiated quartz shows a reduction in density of around 15%, and an increase in chemical reactivity, described by its dissolution rate, similar to a glassy silica. However, calcite shows little change in dissolution rate - although its density noted to reduce by 9%. These differences are correlated with the nature of bonds in these minerals, i.e., being dominantly ionic or covalent, and the rigidity of the mineral's atomic network that is characterized by the number of topological constraints (nc) that are imposed on the atoms in the network. Our outcomes have major implications on the durability of concrete structural elements formed with calcitic or quartzitic aggregates in nuclear power plants.

22 GENERAL STUDIES OF NUCLEAR REACTORS↗
DOE OSTI2017

Prebiotic RNA Polymerisation: Energetics of Nucleotide Adsorption and Polymerisation on Clay Mineral Surfaces

We measured the binding energy and bonding parameters between model nucleotide functional groups and model clay mineral surfaces in solutions of acidic pH. We demonstrate that basal surfaces of clay minerals interact most strongly with nucleobases and show that the adsorption of the phosphate group to clay edges could facilitate polymerisation. Our results suggest that Al- and Fe-rich edge sites behave similarly in nucleotide polymerisation through change of the phosphodiester bond strength. We present an internally consistent set of thermodynamic parameters that represent the nucleotide–clay mineral system.

Jelavic, Stanislov↗
DOE OSTI2020

Hydration structure and water exchange kinetics at xenotime–water interfaces: implications for rare earth minerals separation

Hydration of surface ions gives rise to structural heterogeneity and variable exchange kinetics of water at complex mineral–water interfaces. In this work, we employ ab initio molecular dynamics (AIMD) simulations and water adsorption calorimetry to examine the aqueous interfaces of xenotime, a phosphate mineral that contains predominantly Y 3+ and heavy rare earth elements. Consistent with natural crystal morphology, xenotime is predicted to have a tetragonal prismatic shape, dominated by the {100} surface. Hydration of this surface induces multilayer interfacial water structures with distinct OH orientations, which agrees with recent crystal truncation rod measurements. The exchange kinetics between two adjacent water layers exhibits a wide range of underlying timescales (5–180 picoseconds), dictated by ion–water electrostatics. Adsorption of a bidentate hydroxamate ligand reveals that {100} xenotime surface can only accommodate monodentate coordination with water exchange kinetics strongly depending on specific ligand orientation, prompting us to reconsider traditional strategies for selective separation of rare-earth minerals.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
DOE OSTI2022

Facile synthesis and phase stability of Cu-based Na 2 Cu(SO 4 ) 2 · x H 2 O ( x = 0–2) sulfate minerals as conversion type battery electrodes

Mineral exploration forms a key approach for unveiling functional battery electrode materials. The synthetic preparation of naturally found minerals and their derivatives can aid in designing of new electrodes. Herein, saranchinaite Na 2 Cu(SO 4 ) 2 and its hydrated derivative kröhnkite Na 2 Cu(SO 4 ) 2 ·2H 2 O bisulfate minerals have been prepared using a facile spray drying route for the first time. The phase stability relation during the (de)hydration process was examined synergising in situ X-ray diffraction and thermochemical studies. Kröhnkite forms the thermodynamically stable phase as the hydration of saranchinaite to kröhnkite is highly exothermic (-51.51 ± 0.63 kJ mol -1 ). Structurally, kröhnkite offers a facile 2D pathway for Na+ ion migration resulting in 20 times higher total conductivity than saranchinaite at 60 °C. Both compounds exhibited a conversion redox mechanism for Li-ion storage with the first discharge capacity exceeding 650 mA h g -1 (at 2 mA g -1 vs. Li + /Li) upon discharge up to 0.05 V. Post-mortem analysis revealed that the presence of metallic Cu in the discharged state is responsible for high irreversibility during galvanostatic cycling. This study reaffirms the exploration of Cu-based polyanionic sulfates, which while having limited (de)insertion properties, can be harnessed for conversion-based electrode materials for batteries.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
DOE OSTI2013

Mn(II,III) oxidation and MnO 2 mineralization by an expressed bacterial multicopper oxidase

Reactive Mn(IV) oxide minerals are ubiquitous in the environment and control the bioavailability and distribution of many toxic and essential elements and organic compounds. Their formation is thought to be dependent on microbial enzymes, because spontaneous Mn(II) to Mn(IV) oxidation is slow. Several species of marine Bacillus spores oxidize Mn(II) on their exosporium, the outermost layer of the spore, encrusting them with Mn(IV) oxides. Molecular studies have identified the mnx (Mn oxidation) genes, including mnxG , encoding a putative multicopper oxidase (MCO), as responsible for this two-electron oxidation, a surprising finding because MCOs only catalyze single-electron transfer reactions. Characterization of the enzymatic mechanism has been hindered by the lack of purified protein. By purifying active protein from the mnxDEFG expression construct, we found that the resulting enzyme is a blue (absorption maximum 590 nm) complex containing MnxE, MnxF, and MnxG proteins. Further, by analyzing the Mn(II)- and (III)-oxidizing activity in the presence of a Mn(III) chelator, pyrophosphate, we found that the complex facilitates both electron transfers from Mn(II) to Mn(III) and from Mn(III) to Mn(IV). X-ray absorption spectroscopy of the Mn mineral product confirmed its similarity to Mn(IV) oxides generated by whole spores. Our results demonstrate that Mn oxidation from soluble Mn(II) to Mn(IV) oxides is a two-step reaction catalyzed by an MCO-containing complex. Lastly, with the purification of active Mn oxidase, we will be able to uncover its mechanism, broadening our understanding of Mn mineral formation and the bioinorganic capabilities of MCOs.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
DOE OSTI2022

Amyloid-like amelogenin nanoribbons template mineralization via a low-energy interface of ion binding sites

Protein scaffolds direct the organization of amorphous precursors that transform into mineralized tissues, but the templating mechanism remains elusive. Motivated by models for the biomineralization of tooth enamel, wherein amyloid-like amelogenin nanoribbons guide the mineralization of apatite filaments, we investigated the impact of nanoribbon structure, sequence, and chemistry on amorphous calcium phosphate (ACP) nucleation. Using full-length human amelogenin and peptide analogs with an amyloid-like domain, films of β-sheet nanoribbons were self-assembled on graphite and characterized by in situ atomic force microscopy and molecular dynamics simulations. All sequences substantially reduce nucleation barriers for ACP by creating low-energy interfaces, while phosphoserines along the length of the nanoribbons dramatically enhance kinetic factors associated with ion binding. Furthermore, the distribution of negatively charged residues along the nanoribbons presents a potential match to the Ca–Ca distances of the multi-ion complexes that constitute ACP. These findings show that amyloid-like amelogenin nanoribbons provide potent scaffolds for ACP mineralization by presenting energetically and stereochemically favorable templates of calcium phosphate ion binding and suggest enhanced surface wetting toward calcium phosphates in general.

59 BASIC BIOLOGICAL SCIENCES↗
DOE OSTI2013

MINERAL PROCESSING BY SHORT CIRCUITS IN PROTOPLANETARY DISKS

Meteoritic chondrules were formed in the early solar system by brief heating of silicate dust to melting temperatures. Some highly refractory grains (Type B calcium-aluminum-rich inclusions, CAIs) also show signs of transient heating. A similar process may occur in other protoplanetary disks, as evidenced by observations of spectra characteristic of crystalline silicates. One possible environment for this process is the turbulent magnetohydrodynamic flow thought to drive accretion in these disks. Such flows generally form thin current sheets, which are sites of magnetic reconnection, and dissipate the magnetic fields amplified by a disk dynamo. We suggest that it is possible to heat precursor grains for chondrules and other high-temperature minerals in current sheets that have been concentrated by our recently described short-circuit instability. We extend our work on this process by including the effects of radiative cooling, taking into account the temperature dependence of the opacity; and by examining current sheet geometry in three-dimensional, global models of magnetorotational instability. We find that temperatures above 1600 K can be reached for favorable parameters that match the ideal global models. This mechanism could provide an efficient means of tapping the gravitational potential energy of the protoplanetary disk to heat grains strongly enough to form high-temperature minerals. The volume-filling nature of turbulent magnetic reconnection is compatible with constraints from chondrule-matrix complementarity, chondrule-chondrule complementarity, the occurrence of igneous rims, and compound chondrules. The same short-circuit mechanism may perform other high-temperature mineral processing in protoplanetary disks such as the production of crystalline silicates and CAIs.

36 MATERIALS SCIENCE↗
DOE OSTI2019

Zinc K -edge XANES spectroscopy of mineral and organic standards

Zinc K -edge X-ray absorption near-edge (XANES) spectroscopy was conducted on 40 zinc mineral samples and organic compounds. The K -edge position varied from 9660.5 to 9666.0 eV and a variety of distinctive peaks at higher post-edge energies were exhibited by the materials. Zinc is in the +2 oxidation state in all analyzed materials, thus the variations in edge position and post-edge features reflect changes in zinc coordination. For some minerals, multiple specimens from different localities as well as pure forms from chemical supply companies were examined. These specimens had nearly identical K -edge and post-edge peak positions with only minor variation in the intensity of the post-edge peaks. This suggests that typical compositional variations in natural materials do not strongly affect spectral characteristics. Organic zinc compounds also exhibited a range of edge positions and post-edge features; however, organic compounds with similar zinc coordination structures had nearly identical spectra. Zinc XANES spectral patterns will allow identification of unknown zinc-containing minerals and organic phases in future studies.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Direct observation of anisotropic growth of water films on minerals driven by defects and surface tension

Knowledge of the occurrences of water films on minerals is critical for global biogeochemical and atmospheric processes, including element cycling and ice nucleation. The underlying mechanisms controlling water film growth are, however, misunderstood. Using infrared nanospectroscopy, amplitude-modulated atomic force microscopy, and molecular simulations, we show how water films grow from water vapor on hydrophilic mineral nanoparticles. We imaged films with up to four water layers that grow anisotropically over a single face. Growth usually begins from the near edges of a face where defects preferentially capture water vapor. Thicker films produced by condensation cooling completely engulf nanoparticles and form thicker menisci over defects. The high surface tension of water smooths film surfaces and produces films of inhomogeneous thickness. Nanoscale topography and film surface energy thereby control anisotropic distributions and thicknesses of water films on hydrophilic mineral nanoparticles.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗