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All sources NASA NTRS DOE OSTI

DOE OSTI2021

Proton Nuclear Magnetic Resonance (H NMR) of Glycolate in Real Waste: Developing and Testing Analytical Methods for the Savannah River Site Liquid Waste System

In preparation for implementing the NG acid flowsheet for the SRS LWS, analytical methods for determining glycolate at low concentration are desired to support system management and safety. Previous work documented that the IC method performed well for samples with low to moderate ionic strength. That work also included a scoping effort to determine if an alternate analytical strategy using H NMR would complement and extend the capabilities of the IC method. The H NMR scoping results indicated that the method had the potential to expand glycolate analysis in LWS samples to higher ionic strength tanks/solutions. The scope of this work is to develop innovative proton NMR techniques, including demonstrating ion exchange decontamination protocols needed for application of the technique to real waste samples. Part of radioactive waste processing at SRS uses formic acid to reduce oxidized (Hg 2+ ) to more volatile elemental Hg for steam striping, collecting, and disposal. Under acidic conditions found in the Chemical Processing Cell (CPC) at the Defense Waste Processing Facility (DWPF), formic acid has a much higher hydrogen generation rate than an alternative reductant, glycolic acid. Thus, an NG acid flowsheet has been developed utilizing glycolic acid with the benefit of easing the need for headspace monitoring requirements for hydrogen and ammonia at DWPF. Low concentrations of glycolate are conservatively assumed to be in the recycle stream, which will collect in the Recycle Collection Tank (RCT). The DWPF recycle stream collected in the RCT has a distinct pathway to the LWS waste tanks that feed the 2H and 3H Evaporator. This route involves transfer of the DWPF recycle to Tank 22 in the Concentration, Storage, and Transfer Facilities (CSTF) followed by transfer to the LWS tank farm/evaporators.

12 MANAGEMENT OF RADIOACTIVE AND NON-RADIOACTIVE W↗

DOE OSTI2024

The Case for Reducing Emissions from Heavy-Duty Off-Road Applications via Ducted Fuel Injection

Designers of heavy-duty diesel engines use a variety of techniques to improve efficiency and reduce pollutant emissions. Ducted fuel injection (DFI), high fuel injection pressures, optimized injection orifices, multiple injection sites, and oxygenated fuels are a few techniques used by designers to improve fuel/charge-gas mixtures within the combustion chamber to improve efficiency and emissions results. Ducted fuel injection (DFI) has been proven to substantially reduce soot for low- and mid-load conditions in heavy duty engines, without significantly increasing nitrogen oxides (NO x ). This study investigates the performance of DFI utilizing conventional diesel fuel and the potential the technique has for future research utilizing varieties of test fuels and operating parameter values. Optimization for high engine efficiency and low emissions will help facilitate DFI deployment for substantial environmental benefits in heavy-duty sectors where electrification and/or carbon-free fuels aren’t feasible.

33 ADVANCED PROPULSION SYSTEMS↗

DOE OSTI2026

Development of Industrial Scale Rare Earth Master Alloys from Their Native Oxides for Magnet Production

The objective of the project is to develop an energy-efficient, reduced cost, and single-step critical metal oxide reduction and alloying methodology for the production of NdFeB and SmCo magnets to facilitate the establishment of a sustainable domestic critical materials supply chain. The method consists of an immiscible molten salt flux layer and a higher density molten metal alloy pool (FeB or Co). The rare earth (RE) oxide and a reductant are added to the molten salt layer, where the reductant first strips the oxygen from the rare earth oxide. Subsequently, the separated RE metal diffuses into the molten metal pool below, creating a RE-saturated master alloy. Towards this end, thermodynamic calculations of the reactions between RE oxides, metallic reducing agent, and molten salt bath chemistry have been performed, and the ideal feeds and conditions for extraction and diffusion to produce master alloys were established. Small-scale and scaled experimentation was performed to validate and optimize the feasibility of viable reactions, temperatures, and process conditions with regards to yield, composition, and process efficiency. Finally, full-scale experiments for the production of NdFeB and SmCo magnets were performed, and their performance characteristics were established.

36 MATERIALS SCIENCE↗

NASA NTRS1972

Equilibrium studies with a bearing on lunar rocks.

Review of the results of equilibrium studies of lunar rocks and of synthesized oxide and silicate phases performed in the temperature range from 1000 to 1400 C under strongly reducing conditions of a total pressure of 1 atm. Determined liquidus and solidus temperatures and sequence of appearance of crystalline phases are presented. The studies of synthesized mixtures are concentrated in two main areas, one dealing with subsolidus relations in titanate and spinel phases, the other with liquidus phase relations in simplified iron silicate systems.

Muan, A.↗

NASA NTRS1995

Performance Of Perfluoropolyalkylether Lubricant System

Perfluoro-polyalkylethers (PFPAE) constitute class of fluids having characteristics of high thermal oxidative stability, good vicosity-temperature characteristics, good elastohydrodynamic film-forming capabilities, low volatility, and non-flammability. One unfortunate drawback PFPAE causes severe metal corrosion and fluid degradation when used in oxidizing atmosphere. Reports of interest deal with synthesis of PFPAE-type liquids and development of additive to reduce oxidizing atmosphere degradation. Properties and molecular structures reported in detail. Also lubricant performance over range of conditions.

Paciorek, K.↗

DOE OSTI2020

Microbial sensor system for the assessment of subsurface environments

A microbial sensor, system, and method that can be used to determine a chemical environment and/or substrate concentrations in anaerobic or aerobic environments, such as soils, sediments and ground waters, are disclosed. An exemplary system uses one or more (e.g., inert) measurement electrodes and a reference electrode. The reference electrode can include an electrode exposed to atmospheric oxygen (e.g., a cathode) or an electrode exposed to stable anaerobic or aerobic conditions. The exemplary microbial sensor system measures open-circuit voltage to characterize the chemical (oxidizing or reducing) environment and/or recovery voltage to measure substrate concentrations in the subsurface.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗

DOE OSTI2023

Microbial sensor system for the assessment of subsurface environments

Burge, Scott R.↗

DOE OSTI2025

U redox state tracked in mineralized hydrothermal carbonate with implications for U-Pb geochronology

U-Pb carbonate geochronology can directly constrain the timing and rates of important geological processes. However, the mechanisms and controls on U incorporation, distribution, and retention in carbonate minerals remain unclear, limiting geological interpretations. Here X-ray absorption spectroscopy (µXAS) and in-situ U-Pb carbonate geochronology are combined to temporally track U distribution and redox state in a porphyry-epithermal system. In this setting, multiple generations of carbonate minerals record fluid conditions and processes which control the solubility and deposition of metals, including U. This novel approach provides the first evidence of both oxidized UO 2 2+ and reduced U 4+ species in temporally distinct generations of carbonate within a single sample. Preservation of two different U oxidation states during discrete precipitation events requires U retentivity within older domains, demonstrating that the U-Pb carbonate geochronometer is robust under hydrothermal conditions. Furthermore, crystal zones with abundant fluid/vapour inclusions linked to boiling processes coincide with relatively high levels of U and favourable U/Pb. Targeting carbonate domains with these textures may therefore increase success in U-Pb geochronology. U-Pb carbonate dating combined with µXAS can track the temporal evolution of processes critical for metal deposition in long-lived and multistage hydrothermal-magmatic ore deposit settings.

58 GEOSCIENCES↗

DOE OSTI2024

Reduction of Hg II by Mn II

The reduction of Hg II to Hg I or Hg 0 can lead to significant changes in Hg toxicity and mobility in the environment. Photochemical reduction is the primary process for the reduction of Hg II to Hg 0 in sunlit environments; however, dark reduction of HgII can occur via microbial metabolic processes and/or reduction by reduced natural organic matter, Fe II mineral phases, Fe II sorbed to minerals, or aqueous Fe II . Here, in this study, we demonstrate a novel Hg II reduction pathway involving another environmentally relevant reductant, Mn II . Abiotic reduction of Hg II O by Mn II was studied as a function of pH and anion environment (perchlorate, sulfate, chloride) using X-ray absorption spectroscopy to characterize the solid-phase Hg and Mn species. At circumneutral pH of 7.5, about 70% of Hg II was reduced to elemental Hg 0 within 2 h. In contrast, 12 h were needed to achieve the same extent of reduction at pH 6.9. In the presence of sulfate and chloride, Hg I species were formed. Hg II reduction was initially rapid and coupled with the oxidation of soluble Mn II -oxides to insoluble Mn IV -oxides, followed by a significantly slower reduction of Hg II during the Mn II -catalyzed transformation of the Mn IV -oxides to hydroxide and oxyhydroxide minerals. The observed reduction of Hg II by Mn II at circumneutral pH could be an important transformation pathway for environmental Hg, affecting its bioavailability and mobility under mildly reducing conditions.

59 BASIC BIOLOGICAL SCIENCES↗

NASA NTRS1990

Analysis of Pt/SnO(sub x) during catalysis of CO oxidation

Temperature-programmed reduction using 6kPaH2 suggests that a sample consisting of 3 percent Pt supported directly on SnO2 is, under conditions of catalysis of CO oxidation used here, best represented as 3 percent Pt/SnO sub x, since the support is likely to partially reduced, probably in the vicinity of the metal/oxide interface. Catalytic measurements at 421 to 424 K show that this 3 percent Pt/SnO sub x is significantly more active per unit area of Pt than 6 percent Pt/SiO2 in catalyzing the oxidation of CO. In situ micro-FTIR reveals that while the latter has predominantly linearly bound CO on the surface under reaction conditions, the Pt/SnO sub x also has a species absorbing at 2168 cm(exp -1) which may be CO upon Pt in a positive oxidation state or weakly chemisorbed CO on zero-valent Pt. This may be directly involved in the low temperature oxidation of CO on the Pt/SnO sub x, since being weakly held the activation energy for its surface diffusion to the metal/oxide interface will be low; such mobile species could allow the high rates of surface transport and an increase in the fraction of the surface over which the CO oxidation occurs. FTIR also reveals carbonate-type species on the P/SnO sub c surface.

Sermon, Paul A.↗

DOE OSTI2020

Controls on Iron Reduction and Biomineralization over Broad Environmental Conditions as Suggested by the Firmicutes Orenia metallireducens Strain Z6

Microbial iron reduction is a ubiquitous biogeochemical process driven by diverse microorganisms in a variety of environments. However, it is often difficult to separate the biological from the geochemical controls on bioreduction of Fe(III) oxides. In this study, we investigated the primary driving factor(s) that mediate secondary iron mineral formation over a broad range of environmental conditions using a single dissimilatory iron reducer, Orenia metallireducens strain Z6. A total of 17 distinct geochemical conditions were tested with differing pH (6.5–8.5), temperature (22–50 °C), salinity (2–20% NaCl), anions (phosphate and sulfate), electron shuttle (anthraquinone-2,6-disulfonate), and Fe(III) oxide mineralogy (ferrihydrite, lepidocrocite, goethite, hematite, and magnetite). The observed rates and extent of iron reduction differed significantly with k int between 0.186 and 1.702 mmol L –1 day –1 and Fe(II) production ranging from 6.3% to 83.7% of the initial Fe(III). Using X-ray absorption and scattering techniques (EXAFS and XRD), we identified and assessed the relationship between secondary minerals and the specific environmental conditions. It was inferred that the observed bifurcation of the mineralization pathways may be mediated by differing extents of Fe(II) sorption on the remaining Fe(III) minerals. These results expand our understanding of the controls on biomineralization during microbial iron reduction and aid the development of practical applications.

54 ENVIRONMENTAL SCIENCES↗

DOE OSTI2022

Insight of BaCe 0.5 Fe 0.5 O 3– δ twin perovskite oxide composite for solid oxide electrochemical cells

One-pot synthesized twin perovskite oxide composite of BaCe 0.5 Fe 0.5 O 3–δ (BCF), comprising cubic and orthorhombic perovskite phases, shows triple-conducting properties for promising solid oxide electrochemical cells. Phase composition evolution of BCF under various conditions was systematically investigated, revealing that the cubic perovskite phase could be fully/partially reduced into the orthorhombic phase under certain conditions. The reduction happened between the two phases at the interface, leading to the microstructure change. As a result, the corresponding apparent conducting properties also changed due to the difference between predominant conduction properties for each phase. Based on the revealed phase composition, microstructure, and electrochemical properties changes, a deep understanding of BCF's application in different conditions (oxidizing atmospheres, reducing/oxidizing gradients, cathodic conditions, and anodic conditions) was achieved. Triple-conducting property (H + /O 2– /e – ), fast open-circuit voltage response (~16–~470 mV) for gradients change, and improved single-cell performance (~31% lower polarization resistance at 600°C) were comprehensively demonstrated. Besides, the performance was analyzed under anodic conditions, which showed that the microstructure and phase change significantly affected the anodic behavior.

08 HYDROGEN↗

DOE OSTI2024

Metal-facilitated, sustainable nitroarene hydrogenation under ambient conditions

Hydrogenation is a critical reaction in the chemical industry, yielding a range of important compounds such as fine chemicals, pharmachemicals and agrochemicals. However, conventional hydrogenation typically requires pressurized hydrogen, high temperatures and involves noble metal catalysts. Here, we proposed a two-step hydrogenation process, utilizing water as the hydrogen source for the industrially important reduction of nitroarenes to anilines. A metal or reduced metal oxide, which can be obtained from solar thermal or electrochemical reduction, acts as the active site for nitrobenzene adsorption, H 2 O dissociation and in-situ hydrogen generation. Among the 15 metal and reduced metal oxides investigated, Zn and Sn emerged as highly efficient catalysts for the reduction of a broad range of organic nitro compounds under mild conditions, with H 2 utilization efficiency 1-2 orders of magnitude above the state-of-the-art. The presented protocol provides extra dimensions for designing and optimizing conventional hydrogenation process with an alternative pathway. The reactive hydrogen atoms generated in-situ effectively overcome the barriers associated with hydrogen gas dissolution and its subsequent dissociation on the catalyst surface, thereby greatly enhancing the overall effectiveness for the hydrogenation reaction. This research potentially establishes a sustainable, generally applicable alternative to conventional hydrogenation methods, simultaneously presenting a viable solution for renewable energy storage.

25 ENERGY STORAGE↗

DOE OSTI2024

Production of Carbon Nanomaterials and Sorbents from Domestic U.S. Coal (Final Report)

The main goal of this project was to produce high-value carbon nanomaterials and carbon sorbents from domestic coal resources in a cost-effective manner. Four types of domestic coal samples were processed through a combination of deashing, devolatilization, oxidation, reduction, and activation treatments to produce graphene oxide (GO), reduced graphene oxide (RGO), and activated carbon (AC). The precursors and developed materials were extensively characterized by various methods to investigate the impact of the coal feedstock type on the yield and quality of each product. A commercial graphite-based GO sample was included in the experimental work as the baseline material for comparison with the coal-based materials developed in this work. The performed work also included a technoeconomic analysis and cost estimation for a plant processing 20 tons/day coal, a market evaluation for the graphene materials, and a technology gap analysis. A simple process by concentrated nitric acid oxidation is used to oxidize coal precursors for the production of GO. Fine oxidized coal particles that were separated from larger oxidized coal particles had significantly higher oxygen contents and were identified as coal-based GO samples. Coarse oxidized coal particles were used as precursors for production of AC. Based on the Raman spectroscopy results, coal-based GO samples exhibited G and D bands similar to those of graphite-based GO samples. X-ray photoelectron spectroscopy revealed that coal-based GO samples had surface oxygen contents of ~26-35% that were higher than the oxygen contents of graphite-based GO samples. Larger particles of oxidized coal samples were activated under different conditions to produce high surface area functionalized AC. Prepared materials had surface areas exceeding 1,500 m 2 /g and pore volumes more than 1 cm 3 /g with different pore size distributions. Reduced graphene oxide samples were prepared by thermal reduction of both coal-based and graphite-based GO samples at 170-2800 ºC. Coal-based and graphite-based RGO samples exhibited similar carbon contents, Raman spectra, and XRD profiles. Heat treatment above 1500 ºC shifted RGO to synthetic graphite. Among anthracite, bituminous, subbituminous, and lignite coals tested, anthracite was the best precursor to produce carbon nanomaterials exhibiting properties similar to those of graphite-based materials. Anthracite-based carbon nanomaterials also had the highest production yields. Technoeconomic analysis estimated the production cost of GO and RGO for anthracite-based samples at about 2,600 and 4,200 $/ton, respectively, which is about two orders of magnitude lower than the current estimated price of graphite-based materials. Several gaps to further develop the proposed technology were identified and discussed that include process and equipment optimization, process integration, need for additional bench- and pilot-scale experiments, and other items to reduce the scale up risk. Market analysis reports suggested a compound annual growth rate of 40% for graphene and related materials. Short-term applications include composites, inks, and coatings. However, energy storage applications appear to be the dominant potential long-term applications. Different applications of coal-based GO and RGO need to be explored and clear metrics and standards for each application need to be developed.

01 COAL, LIGNITE, AND PEAT↗

DOE OSTI2025

Comparative Mechanical Properties Analysis of Triple Ion-Beam Irradiated and Neutron Irradiated Potential Plasma Facing Components

Abstract Several classes of materials are being proposed for use in fusion reactors including oxide dispersion strengthened (ODS) and reduced activation ferritic-martensitic (RAF/M) steels to withstand the severe and harsh conditions. In this work, the mechanical properties of a Fe-16Cr-4Al-2W-0.3Ti-0.3Y 2 O 3 (K3) (ODS) ferritic steel and a Fe-8.9Cr-1.1W-0.47Mn-0.2V-0.14Ta-0.11C (Eurofer 97) (RAF/M) steel) after triple ion beam irradiation were locally evaluated utilizing in-situ micro-pillar compression tests, and continuous stiffness/quasi-static nanoindentation. No change in mechanical properties was observed in the K3 ODS steel. However, the Eurofer 97 RAF/M steel exhibited radiation-induced effects via increases in yield strength. Micro-pillar techniques were expanded to neutron-irradiated materials via an in-situ testing technique employing lift-out methods on Fe-14Cr-0.9Ti-0.3Mo-0.25Y 2 O 3 (MA957) ODS ferritic steel. Both the non-irradiated and irradiated compressive yield stresses of the MA 957 micro-pillars were in good agreement with bulk yield stress values reported in the literature, suggesting that the lift-out micro-pillar compression testing technique is a promising method. The demonstration of these techniques on ion beam and neutron irradiated ODS steels and ion beam RAF/M steels gives information to inform models of the material degradation during use in a fusion device.

alloys↗

DOE OSTI2024

Thermodynamics and kinetics of interconversion between platinum nanoparticles and cations in zeolites

In metal-containing zeolites, sintering and redispersion processes exercise control over the identity of metal site structures, but the thermodynamic and kinetic factors that influence these molecular-level processes are not completely understood. Furthermore, we assess the ability of first principles informed free energy models (for supported and unsupported nanoparticles) and kinetic models integrating Ostwald ripening with atom trapping to describe the interconversion between Pt cations and nanoparticles encapsulated in chabazite (CHA) zeolites. Density functional theory-derived thermodynamic phase diagrams show that the interconversion between cations, favored in oxidizing environments, and particles, favored in reducing environments, is fully reversible within a wide range of their respective conditions (temperatures and pressures) for CHA and several other zeolite topologies. Kinetic Monte Carlo simulations of Pt redispersion are consistent with experimentally observed redispersion kinetics of encapsulated Pt nanoparticles in CHA zeolites, and model results suggest the zeolite host imparts additional stability for Pt nanoparticles. We envision our thermodynamic and kinetic models for Pt-CHA are also capable of describing nanoparticle and cation interconversions for other zeolite frameworks under similar conditions.

36 MATERIALS SCIENCE↗

DOE OSTI2022

Carbonate Minerals and Dissimilatory Iron-Reducing Organisms Trigger Synergistic Abiotic and Biotic Chain Reactions under Elevated CO 2 Concentration

Increasing CO 2 emission has resulted in pressing climate and environmental issues. While abiotic and biotic processes mediating the fate of CO 2 have been studied separately, their interactions and combined effects have been poorly understood. To explore this knowledge gap, an iron-reducing organism, Orenia metallireducens, was cultured under 18 conditions that systematically varied in headspace CO 2 concentrations, ferric oxide loading, and dolomite (CaMg(CO 3 ) 2 ) availability. The results showed that abiotic and biotic processes interactively mediate CO 2 acidification and sequestration through "chain reactions", with pH being the dominant variable. Specifically, dolomite alleviated CO 2 stress on microbial activity, possibly via pH control that transforms the inhibitory CO 2 to the more benign bicarbonate species. The microbial iron reduction further impacted pH via the competition between proton (H + ) consumption during iron reduction and H + generation from oxidization of the organic substrate. Under Fe(III)-rich conditions, microbial iron reduction increased pH, driving dissolved CO 2 to form bicarbonate. Spectroscopic and microscopic analyses showed enhanced formation of siderite (FeCO 3 ) under elevated CO 2 , supporting its incorporation into solids. In conclusion, the results of these CO 2 -microbe-mineral experiments provide insights into the synergistic abiotic and biotic processes that alleviate CO 2 acidification and favor its sequestration, which can be instructive for practical applications (e.g., acidification remediation, CO 2 sequestration, and modeling of carbon flux).

54 ENVIRONMENTAL SCIENCES↗

NASA NTRS1973

Characteristics of a gelled liquid hyprogen polyphenylene oxide (PPO) foam open-cell insulation system, phase 1

A large scale gel production and storage facility and a small scale facility, the latter used for detailed visual examination of the gel/PPO foam interface, were developed. A subcontract was given to investigate techniques for the production of gelled liquid hydrogen, develop a process design for scale-up to a 1.89 cu m (500 gallon) gel production and storage facility, determine gel transfer characteristics, determine the solubility rate of gaseous helium in the gel, and investigate the gross gel/PPO foam interfacial phenomena. An inside-tank process for scaled-up production of gelled liquid hydrogen was selected. No detectable gel structure degradation occurred during repeated shearing. The viscosity of gelled liquid hydrogen at shear rates of 300/sec and higher is 2 to 5-fold greater than that of neat liquid hydrogen. No clogging problems were encountered during the transfer of gelled liquid hydrogen through warmed transfer lines. The solubility rate of helium in liquid hydrogen was significantly reduced by the presence of gel structure. The boil-off rates from gelled liquid hydrogen were reduced from 25 to 50 percent compared to those observed for the neat liquid hydrogen under compatible conditions. The polyphenylene oxide (PPO) foam insulation was found to be compatible with liquid ethane.

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