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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 685 records · Page 38
All sourcesNASA NTRSDOE OSTI
DOE OSTI2016

Study of Reactor BN-350 Wastewater Impact on the Environment

The fast neutron reactor BN-350 had a dual purpose: steam production and plutonium accumulation. The steam produced in the reactor was used to generate electricity (up to 150 MW) and desalination of seawater (up to 120,000 tons/day). The BN-350 reactor became operational in July 1973; its design operation lifetime was 20 years. After expiration of the reactor design lifetime in July 1993, its subsequent operation was continued according to the annual decisions on extension of the reactor operation, by one year. The reactor has been idle since December 1998. On April 22, 1999 Resolution No. 456 'About decommissioning of the BN-350 reactor in Aktau, Mangistau region' was adopted by the RK Government. Thus, the total operation period of the reactor was more than 25 years. One of the important issues related to the long-term operation of a radiation-hazardous facility, such as the BN-350 reactor, is to assess its impact on the environment. The necessity and urgency of detailed studies of the radiation situation is explained by the location of the Caspian Sea and Aktau city in the area of the BN-350 reactor's potential impact. This paper describes the preliminary results of the evaluation of the BN-350 reactor's effect on the level of radionuclide contamination of surface water, including the Caspian Sea via the mechanism of radionuclide discharge in wastewater. (authors)

12 MANAGEMENT OF RADIOACTIVE AND NON-RADIOACTIVE W↗
DOE OSTI2015

Electrical properties of methane hydrate + sediment mixtures: The σ of CH 4 Hydrate + Sediment

Knowledge of the electrical properties of multicomponent systems with gas hydrate, sediments, and pore water is needed to help relate electromagnetic (EM) measurements to specific gas hydrate concentration and distribution patterns in nature. We built a pressure cell capable of measuring in situ electrical properties of multicomponent systems such that the effects of individual components and mixing relations can be assessed. We first established the temperature-dependent electrical conductivity (σ) of pure, single-phase methane hydrate to be ~5 orders of magnitude lower than seawater, a substantial contrast that can help differentiate hydrate deposits from significantly more conductive water-saturated sediments in EM field surveys. We report σ measurements of two-component systems in which methane hydrate is mixed with variable amounts of quartz sand or glass beads. Sand by itself has low σ but is found to increase the overall σ of mixtures with well-connected methane hydrate. Alternatively, the overall σ decreases when sand concentrations are high enough to cause gas hydrate to be poorly connected, indicating that hydrate grains provide the primary conduction path. Our measurements suggest that impurities from sand induce chemical interactions and/or doping effects that result in higher electrical conductivity with lower temperature dependence. Finally, these results can be used in the modeling of massive or two-phase gas-hydrate-bearing systems devoid of conductive pore water. Further experiments that include a free water phase are the necessary next steps toward developing complex models relevant to most natural systems.

03 NATURAL GAS↗
DOE OSTI2016

Determining the flux of methane into Hudson Canyon at the edge of methane clathrate hydrate stability: METHANE FLUX INTO HUDSON CANYON

Methane seeps were investigated in Hudson Canyon, the largest shelf-break canyon on the northern U.S. Atlantic Margin. The seeps investigated are located at or updip of the nominal limit of methane clathrate hydrate stability. The acoustic identification of bubble streams was used to guide water column sampling in a 32 km 2 region within the canyon's thalweg. By incorporating measurements of dissolved methane concentration with methane oxidation rates and current velocity into a steady state box model, the total emission of methane to the water column in this region was estimated to be 12 kmol methane per day (range: 6–24 kmol methane per day). These analyses suggest that the emitted methane is largely retained inside the canyon walls below 300 m water depth, and that it is aerobically oxidized to near completion within the larger extent of Hudson Canyon. Based on estimated methane emissions and measured oxidation rates, the oxidation of this methane to dissolved CO 2 is expected to have minimal influences on seawater pH.

58 GEOSCIENCES↗
DOE OSTI2023

Membranes in Solar-Driven Evaporation: Design Principles and Applications

In this study, solar-driven evaporation process brings exciting opportunities to recover clean water and resources in a sustainable way from diverse sources like seawater and wastewater. Separation membranes, as a vital material in many environmental and energy applications, can contribute significantly to this process owing to their structural features. However, the unique roles of membranes in solar evaporator construction and process design are seldom recognized and not summarized yet from scientific principles and application demands, which forms the motivation of this review. Herein, the roles of membranes in different processes based on solar-driven evaporation are focused and the design principles of membrane materials and devices to meet the requirements of these applications are discussed. Fabrication strategies for photothermal membranes are introduced primarily, followed by a discussion on how to design membrane materials, devices, and processes to pursue optimal performance and realize advanced functions accompanied by evaporation. Furthermore, the future of this field is forecast with both challenges and opportunities.

14 SOLAR ENERGY↗
DOE OSTI2018

Covalent Organic Frameworks as a Decorating Platform for Utilization and Affinity Enhancement of Chelating Sites for Radionuclide Sequestration

The potential consequences of nuclear events and the complexity of nuclear waste management motivate the development of selective solid-phase sorbents to provide enhanced protection. Herein, we show that two dimensional covalent organic frameworks (COFs) with unique structures possess all the traits to be well-suited as a platform for the deployment of highly efficient sorbents such that they exhibit remarkable performance, as demonstrated by uranium capture. The chelating groups laced on the open one dimensional channels exhibit exceptional accessibility, allowing significantly higher utilization efficiency. In addition, the two dimensional extended polygons packed closely in an eclipsed fashion bring chelating groups in adjacent layers parallel to each other, which may facilitate their cooperation, thereby leading to high affinity towards specific ions. As a result, the amidoxime functionalized COFs far outperform their corresponding amorphous analogues in terms of adsorption capacities, kinetics, and affinities

Sun, Qi↗
DOE OSTI2018

A Highly Stretchy, Transparent Elastomer with the Capability to Automatically Self-Heal Underwater

Polymer materials that are able to self-heal in humid conditions or even in water are highly desirable for their industrial applications. However, the development of underwater self-healing polymer materials is very challenging since water molecules can readily disturb traditional noncovalent bonds, such as saturate the hydrogen bonds, coordinate with the metal cation, as well as solvate the ions. Here, a new type of dipole–dipole interactions is employed as the driving force, combining with highly polar and hydrophobic fluorinated polymers, to successfully demonstrate an underwater self-healing elastomer. Additionally, the polymer materials are transparent and stretchable. They can remain stable underwater for months without significant decay of mechanical properties. Upon mechanical damage, the material is able to self-heal automatically in air, underwater, and under very harsh aqueous conditions (including seawater, highly acidic media, and highly basic media, etc.).

36 MATERIALS SCIENCE↗
DOE OSTI2021

Uranium In Situ Electrolytic Deposition with a Reusable Functional Graphene-Foam Electrode

Nuclear fission produces 400 GWe which represents 11% of the global electricity output. Uranium is the essential element as both fission fuel and radioactive waste. Therefore, the recovery of uranium is of great importance. In this study, an in situ electrolytic deposition method to extract uranium from aqueous solution is reported. A functionalized reduced graphene oxide foam (3D-FrGOF) is used as the working electrode, which acts as both a hydrogen evolution reaction catalyst and a uranium deposition substrate. The specific electrolytic deposition capacity for U(VI) ions with the 3D-FrGOF is 4560 mg g –1 without reaching saturation, and the Coulombic efficiency can reach 54%. Moreover, reduction of the uranium concentration in spiked seawater from 3 ppm to 19.9 ppb is achieved, which is lower than the US Environmental Protection Agency uranium limits for drinking water (30 ppb). Furthermore, the collection electrode can be efficiently regenerated and recycled at least nine times without much efficiency fading, by ejecting into 2000 ppm concentrated uranium solution in a second bath with reverse voltage bias. All these findings open new opportunities in using free-standing 3D-FrGOF electrode as an advanced separation technique for water treatment.

36 MATERIALS SCIENCE↗
DOE OSTI2018

Chinese Ink: A Powerful Photothermal Material for Solar Steam Generation

Solar steam generation offers signifcant promise in alleviating fresh water crises, particularly in regions with accessible seawater and abundant insolation. Affordable, efficient, and environmentally friendly photothermal materials are needed to fabricate sunlight-driven evaporation devices. In this work, Chinese ink, a carbon-based paint used in traditional painting and calligraphy, is readily coated on diverse substrates and stabilized by atomic layer deposition (ALD) for solar steam generation. The ALD/Chinese ink coating exhibits strong and broad light absorption from the NIR to UV regions. Both ALD/Chinese-ink-coated membranes and wood display excellent photothermal properties and superior evaporation performance under simulated sunlight. This study demonstrates the potential of ALD/Chinese ink coating to achieve higher evaporation rate and efficiency by utilizing substrates with rough, structured surfaces and low thermal conductivity.

36 MATERIALS SCIENCE↗
DOE OSTI2022

Bioinspired Macrocyclic Molecule Supported Two‐Dimensional Lamellar Membrane with Robust Interlayer Structure for High‐Efficiency Nanofiltration

Abstract 2D lamellar membranes (2DLMs) are used for efficient desalination and nanofiltration. However, weak interactions between adjacent stacked nanosheets result in susceptibility to swelling that limits practical applicability. Inspired by the super adhesion of multi‐point suction cups on octopus tentacles, a 2DLM is constructed from Ti 3 C 2 T x MXene supported by the macrocyclic “multi‐point” molecule cucurbit[5]uril (CB5) and demonstrated for nanofiltration of methyl blue (MB) and enrichment of uranyl carbonate. Experimental results and density functional theory calculations indicate that CB5 rivets to the surface of the nanoflakes through strong stable interactions between its multiple binding sites and surface hydroxyl functional groups on MXene nanosheets. This novel 2DLM exhibits excellent nanofiltration performance (69 L m −2 h −1 bar −1 permeance with 93.6% rejection for MB) and can be recycled at least 30 times without significant degradation. The 2DLM exhibits excellent swelling resistance at high salinity, with a demonstration of selective enrichment of uranyl carbonate from artificial water and natural seawater. The results provide a new strategy for constructing highly stable 2DLMs with interlayer spacing controllable from sub‐nano to nanometer scales, for size‐selective sieving of molecules and ions, high‐efficiency nanofiltration, and other applications.

38 RADIATION CHEMISTRY, RADIOCHEMISTRY, AND NUCLEA↗
DOE OSTI2025

Rapid Synthesis of Carbon‐Supported Ru‐RuO₂ Heterostructures for Efficient Electrochemical Water Splitting

Abstract Development of high‐performance electrocatalysts for water splitting is crucial for a sustainable hydrogen economy. In this study, rapid heating of ruthenium(III) acetylacetonate by magnetic induction heating (MIH) leads to the one‐step production of Ru‐RuO₂/C nanocomposites composed of closely integrated Ru and RuO₂ nanoparticles. The formation of Mott‐Schottky heterojunctions significantly enhances charge transfer across the Ru‐RuO 2 interface leading to remarkable electrocatalytic activities toward both hydrogen evolution reaction (HER) and oxygen evolution reaction (OER) in 1 m KOH. Among the series, the sample prepares at 300 A for 10 s exhibits the best performance, with an overpotential of only −31 mV for HER and +240 mV for OER to reach the current density of 10 mA cm⁻ 2 . Additionally, the catalyst demonstrates excellent durability, with minimal impacts of electrolyte salinity. With the sample as the bifunctional catalysts for overall water splitting, an ultralow cell voltage of 1.43 V is needed to reach 10 mA cm⁻ 2 , 160 mV lower than that with a commercial 20% Pt/C and RuO₂/C mixture. These results highlight the significant potential of MIH in the ultrafast synthesis of high‐performance catalysts for electrochemical water splitting and sustainable hydrogen production from seawater.

Pan, Dingjie [Department of Chemistry and Biochemi↗
DOE OSTI2026

A PRACTICAL ELECTRODIALYSIS MODEL FOR ACCELERATING SYSTEM DEVELOPMENT

Empirical optimization of electrodialysis (ED) is dependent on repetitive experiments with incremental adjustments, which is cost prohibitive at scale. While models can reduce the costs associated with optimization and scale-up, existing ED models are limited in application to specific use cases and tend to be developed for the exploration of specific transport phenomena. The field requires a practical system-level model, generalized for the broad range of ED systems. This work presents a modeling framework that enables rapid evaluation of membrane stack design, flow configuration, scale, and operational inputs. Across applications spanning 1 L to 5400 L; use of conventional and bipolar membranes; operation in continuous, batch and fed-batch modes; and feedstocks including seawater, brine, wastewater, and manure hydrolysate, the model achieves a mean R2 of 0.978 for concentration-time profiles and links design choices to techno-economic trade-offs, enabling cost-aware prioritization of system configurations.

Bipolar Membrane↗
DOE OSTI2018

Harnessing a methane‐fueled, sediment‐free mixed microbial community for utilization of distributed sources of natural gas

Abstract Harnessing the metabolic potential of uncultured microbial communities is a compelling opportunity for the biotechnology industry, an approach that would vastly expand the portfolio of usable feedstocks. Methane is particularly promising because it is abundant and energy‐rich, yet the most efficient methane‐activating metabolic pathways involve mixed communities of anaerobic methanotrophic archaea and sulfate reducing bacteria. These communities oxidize methane at high catabolic efficiency and produce chemically reduced by‐products at a comparable rate and in near‐stoichiometric proportion to methane consumption. These reduced compounds can be used for feedstock and downstream chemical production, and at the production rates observed in situ they are an appealing, cost‐effective prospect. Notably, the microbial constituents responsible for this bioconversion are most prominent in select deep‐sea sediments, and while they can be kept active at surface pressures, they have not yet been cultured in the lab. In an industrial capacity, deep‐sea sediments could be periodically recovered and replenished, but the associated technical challenges and substantial costs make this an untenable approach for full‐scale operations. In this study, we present a novel method for incorporating methanotrophic communities into bioindustrial processes through abstraction onto low mass, easily transportable carbon cloth artificial substrates. Using Gulf of Mexico methane seep sediment as inoculum, optimal physicochemical parameters were established for methane‐oxidizing, sulfide‐generating mesocosm incubations. Metabolic activity required >∼40% seawater salinity, peaking at 100% salinity and 35 °C. Microbial communities were successfully transferred to a carbon cloth substrate, and rates of methane‐dependent sulfide production increased more than threefold per unit volume. Phylogenetic analyses indicated that carbon cloth‐based communities were substantially streamlined and were dominated by Desulfotomaculum geothermicum . Fluorescence in situ hybridization microscopy with carbon cloth fibers revealed a novel spatial arrangement of anaerobic methanotrophs and sulfate reducing bacteria suggestive of an electronic coupling enabled by the artificial substrate. This system: 1) enables a more targeted manipulation of methane‐activating microbial communities using a low‐mass and sediment‐free substrate; 2) holds promise for the simultaneous consumption of a strong greenhouse gas and the generation of usable downstream products; and 3) furthers the broader adoption of uncultured, mixed microbial communities for biotechnological use.

03 NATURAL GAS↗
DOE OSTI2015

Aqueous Sulfate Separation by Sequestration of [(SO 4 ) 2 (H 2 O) 4 ] 4− Clusters within Highly Insoluble Imine‐Linked Bis‐Guanidinium Crystals

Abstract Selective crystallization of sulfate with a simple bis‐guanidinium ligand, self‐assembled in situ from terephthalaldehyde and aminoguanidinium chloride, was employed as an effective way to separate the highly hydrophilic sulfate anion from aqueous solutions. The resulting bis‐iminoguanidinium sulfate salt has exceptionally low aqueous solubility ( K sp =2.4×10 −10 ), comparable to that of BaSO 4 . Single‐crystal X‐ray diffraction analysis showed the sulfate anions are sequestered as [(SO 4 ) 2 (H 2 O) 4 ] 4− clusters within the crystals. Variable‐temperature solubility measurements indicated the sulfate crystallization is slightly endothermic ( ΔH cryst =3.7 kJ mol −1 ), thus entropy driven. The real‐world utility of this crystallization‐based approach for sulfate separation was demonstrated by removing up to 99 % of sulfate from seawater in a single step.

Custelcean, Radu↗
DOE OSTI2015

Aqueous Sulfate Separation by Sequestration of [(SO 4 ) 2 (H 2 O) 4 ] 4 Clusters within Highly Insoluble Imine-Linked Bis-Guanidinium Crystals

Quantitative removal of sulfate from seawater was achieved by selective crystallization of the anion with a bis(guanidinium) ligand self-assembled in situ through imine condensation of simple components. The resulting crystalline salt has an exceptionally low aqueous solubility, on a par with BaSO 4 . Single-crystal X-ray diffraction analysis revealed pairs of sulfate anions clustered together with four water molecules within the crystals.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
DOE OSTI2018

V IV O and V IV Species Formed in Aqueous Solution by the Tridentate Glutaroimide–Dioxime Ligand – An Instrumental and Computational Characterization

Complexation of V IV in aqueous solution with glutaroimide–dioxime (H 3 L), a ligand proposed for the possible sequestration of uranium from seawater, was studied by the combined application of spectroscopic (EPR and UV/Vis), spectrometric (ESI‐MS), electrochemical (CV), and computational (DFT) techniques. The results indicate that a rare non‐oxido V IV species, with formula [V IV L 2 ] 2– , is formed in the pH range 3–5. It transforms into a usual V IV O complex, [V IV OL(OH)] 2– , at pH > 6. The non‐oxido species is characterized by a “ type 3 ” EPR spectrum with A z ≈ 126 × 10 –4 cm –1 and a UV/Vis signal with ε > 2000 m –1 cm –1 in the visible region. The detection of V V species by ESI‐MS spectrometry was related to two possible oxidation processes, the first one in solution and the second one in‐source during the recording of the spectra. The cyclic voltammogram of [V IV L 2 ] 2– shows two quasi‐reversible processes, at E 1/2 = –0.75 V and E 1/2 = 0.03 V, assigned to the V IV /V III reduction and V IV /V V oxidation, respectively. All the experimental results were verified by DFT calculations, which indicated that the geometry of the non‐oxido V IV complex is intermediate between an octahedron and a trigonal prism and allowed us to predict its 51 V hyperfine coupling (HFC) tensor A , the electron absorption spectrum, the two redox processes in the cyclic voltammogram, and the electronic structure that, in turn, determines its EPR and UV/Vis behavior.

Sanna, Daniele↗
DOE OSTI2019

Effects of Dissolved Organic Carbon on Copper Toxicity to Embryos of Mytilus galloprovincialis as Measured by Diffusive Gradient in Thin Films

Diffusive Gradient in Thin-film (DGT), a passive sampling method, has the potential to better quantify the bioavailable fraction of Cu in seawater, when determining toxicological endpoints, versus grab samples evaluated for total or dissolved Cu. In the present study, laboratory exposure of DGTs and Mediterranean mussel (M. galloprovincialis) embryos at varying concentrations of dissolved organic carbon (DOC) and Cu were performed to resolve the degree to which mimicry of toxicity-buffering occurs in passive sampler quantification. Studies were performed in water collected from Sequim Bay, Washington, USA, spiked with Suwannee River Natural Organic Matter (SRNOM) and Cu(II)SO4. The results provide preliminary EC50s ranging from 4.8 to 11.5 µg/L as CDGT Cu over the span of 0.892 to 8.28 mg/L DOC. M. galloprovincialis was selected as the relevant organism for this correlation based on current consensus for deriving water criteria values, which are based solely from Mytilus spp. toxicological study final acute values, maintaining the intent of protecting environmental and commercial interests to the fauna regarded as most sensitive to Cu input in the marine environment. The present study provides an initial DGT response by which coastal DOC pools with varying functional binding group mixtures can be compared to discern the applicability of broad use for quantifying biological effects at time scales integrated to account for pulsed-input to marine waters.

copper, Bioavailability, Diffusive Gradient in Thi↗
DOE OSTI2019

Efficient Solar‐Thermal Distillation Desalination Device by Light Absorptive Carbon Composite Porous Foam

Abstract Solar‐thermal driven desalination based on porous carbon materials has promise for fresh water production. Exploration of high‐efficiency solar desalination devices has not solved issues for practical application, namely complicated fabrication, cost‐effectiveness, and scalability. Here, direct solar‐thermal carbon distillation (DS‐CD) tubular devices are introduced that have a facile fabrication process, are scalable, and use an inexpensive but efficient microporous graphite foam coated with carbon nanoparticle and superhydrophobic materials. The “black” composite foam serving as a solar light absorber heats up salt water effectively to produce fresh water vapor, and the superhydrophobic surface of the foam traps the liquid feed in the device. Two proof‐of‐principle distillation systems are adopted, i.e., solar still and membrane distillation and the fabricated devices are evaluated for direct solar desalination efficiency. For the solar still, nanoparticle and fluorosilane coatings on the porous surface increase the solar energy absorbance, resulting in a solar‐steam generation efficiency of 64% from simulated seawater at 1 sun. The membrane distillation demonstrates excellent vapor production (≈6.6 kg m ‐2 h ‐1 ) with >99.5% salt rejection under simulated 3 sun solar‐thermal irradiation. Unlike traditional solar desalination, the adaptable DS‐CD can easily be scaled up to larger systems such as high‐temperature tubular modules, presenting a promising solution for solar‐energy‐driven desalination.

42 ENGINEERING↗
DOE OSTI2019

Distribution of mercury-cycling genes in the Arctic and equatorial Pacific Oceans and their relationship to mercury speciation

Humans are exposed to potentially harmful amounts of the neurotoxin monomethylmercury (MMHg) through consumption of marine fish and mammals. However, the pathways of MMHg production and bioaccumulation in the ocean remain elusive. In anaerobic environments, inorganic mercury (Hg) can be methylated to MMHg through an enzymatic pathway involving the hgcAB gene cluster. Recently, hgcA-like genes have been discovered in oxygenated marine water, suggesting the hgcAB methylation pathway, or a close analog, may also be relevant in the ocean. Using polymerase chain reaction amplification and shotgun metagenomics, we searched for but did not find the hgcAB gene cluster in Arctic Ocean seawater. However, we detected Hg-cycling genes from the mer operon (including organomercury lyase, merB), and hgcA-like paralogs (i.e., cdhD) in Arctic Ocean metagenomes. Finally, our analysis of Hg biogeochemistry and marine microbial genomics suggests that various microorganisms and metabolisms, and not just the hgcAB pathway, are important for Hg methylation in the ocean.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗