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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 1,531 records · Page 85
All sourcesNASA NTRSDOE OSTI
DOE OSTI2014

ARPA-E / Achieving at 10,000 GPU Permeance for Post-Combustion Carbon Capture with Gelled Ionic Liquid-Based Membranes

Carbon dioxide (CO 2 ) makes up 78% of anthropogenic greenhouse gas production and has been linked to global climate change and ocean acidification. Therefore, as climate change becomes an increasingly unavoidable environmental, industrial, and political issue, it is desirable to develop technology capable of economically separating and sequestering large amounts of CO 2 . This separation and sequestration technology is also likely to play a role in maintaining the economic value of fossil fuels in the event of a concerted global CO 2 mitigation effort. The initial step toward this technology is to identify and develop an economically viable method of separating CO 2 from flue gas at large point sources such as coal-fired power plants. As an alternate CO 2 capture technology, polymer-based membrane separations offer relatively low operating costs with low-maintenance requirements. Therefore, the development of highly selective and permeable membranes for the separation and ultimate sequestration of CO 2 is of vital importance.

36 MATERIALS SCIENCE↗
NASA NTRS1979

The solubility of olivine in basaltic liquids - An ionic model

A model is presented which enables the temperature at which olivine is in equilibrium with any alkali-depleted basaltic compound to be calculated to within + or - 30 C. It is noted that the error increases substantially when applied to terrestrial basalts which contain several weight percent alkalis. In addition the model predicts and quantifies the reduced activity of SiO4(4-) monomers due to increasing SiO2 concentrations in the melt. It is shown that the coordination of alumina in melts which precipitate olivine only appears to be dominantly octahedral, while titanium acts as a polmerizing agent by interconnecting previously isolated SiO4(4-) monomers. It is concluded that the model is sufficiently sensitive to show that there are small repulsive forces between Mg(2+) and calcium ions which are in association with normative diopside in the melt.

Herzberg, C. T.↗
DOE OSTI2019

Water in Solutions of Chaotropic and Kosmotropic Salts: A Differential Scanning Calorimetry Investigation

We report the use of aqueous phase separations via aqueous biphasic systems (ABS) has been widely explored in the recent decades. For wider and more “intelligent” applications, it is important to look below the surface and study these systems thoroughly at a fundamental level. Two important questions still unsolved are how do polymers and ions of different types organize water (if they in fact they do so) and how does it affect the separation of phases? In the present work, differential scanning calorimetry (DSC) was used to relate ABS phase diagrams and the behavior of water in aqueous solutions containing kosmotropic salts (K 3 PO 4 or (NH 4 ) 2 SO 4 ), a chaotropic ionic liquid ([C 4 mim]Cl), or a polymer (PEG-2000), all of which are reported components of ABS, and their mixtures. Additional DSC transitions were observed for the two classes of salts which could be assigned based on the fundamental differences between their interactions with water, suggesting that it is the differences in the abilities of kosmotropic and chaotropic salts to interact with water which result in the phase separation phenomena observed. The DSC measurements of solutions of PEG-2000 and (NH 4 ) 2 SO 4 indicate that aqueous solutions of PEG-2000 supercool and potentially enter a glassy state that exhibits devitrification upon heating. The devitrified state exhibits a clear eutectic with water. Mixtures of the polymer and salt continue to exhibit all the features observed for the pure components. These results suggest that the mixtures are phase separated and consist of largely separate concentrated solutions of PEG-2000 and (NH 4 ) 2 SO 4 , indicating an entropy-driven phase separation. The DSC analysis of these systems further refines the understanding of kosmotropic and chaotropic solutes into more specific phenomena for each compound. Lastly, this work suggests that DSC can be used to understand the role of each salt/component in ABS.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
DOE OSTI2019

Pushing data quality for laboratory pair distribution function experiments

Over the past decade, some studies with laboratory pair distribution function (PDF) data emerged. Yet, limited Q max or instrumental resolution impeded in-depth structural refinements. With more advanced detector technologies, the question arose how to design novel PDF equipment for laboratories that will allow decent PDF refinements over r = 1–70 Å. It is crucial to reflect the essential requirements, namely, monochromatic X-rays, suppression of air scattering, instrumental resolution, and overall measurement times. The result is a novel PDF setup based on a STOE STADI P powder diffractometer in transmission-/Debye-Scherrer geometry with monochromatic Ag Kα 1 radiation, featuring a MYTHEN2 4K detector covering a Q range of 0.3–20.5 Å –1 . PDF data are collected in a moving PDF mode within 6 h. Structural signatures of liquids can be satisfactorily resolved in the PDF as shown for the ionic liquid hmimPF 6 . The high instrumental resolution is mirrored in low q damp values determined from LaB 6 measurements. PDF data from a powder sample of ca. 7 nm TiO 2 nanoparticles were successfully refined over up to 70 Å with goodness-of-fit values R w < 0.22 (respectively R w = 0.18 over 30 Å), thanks to the low background and high instrumental resolution, hereby enlarging the accessible r range by several tens of Angstroms compared to previous laboratory PDF studies.

47 OTHER INSTRUMENTATION↗
DOE OSTI2019

Assessing Pair Interaction Potentials of Nanoparticles on Liquid Interfaces

The pair interaction potentials of polymer-grafted silica nanoparticles (NPs) at liquid surfaces were confirmed by scanning electron microscopy, exploiting the nonvolatility of ionic liquids to stabilize the specimens against microscope vacuum. Even at near contact, individual, two-dimensionally well-dispersed NPs were resolved. The potential of mean force, reduced to the pair interaction potential for dilute NPs, was extracted with good accuracy from the radial distribution function, as both NP diameter and grafted polymer chain length were varied. Although NP polydispersity somewhat broadened the core repulsion, the pair potential well-approximated a hard sphere interaction, making these systems suitable for model studies of interfacially bound NPs. For short (5 kDa) poly(ethylene glycol) ligands, a weak (< k B T ) long-range attraction was discerned, and for ligands of identical length, pair potentials overlapped for NPs of different diameter; the attraction is predicted to arise from ligand-induced menisci. To understand better the interactions underlying the pair potential, NP surface-binding energies were measured by interfacial tensiometry, and NP contact angles were analyzed by atomic force microscopy and transmission electron microscopy.

77 NANOSCIENCE AND NANOTECHNOLOGY↗
DOE OSTI2023

Quantification of zwitterion betaine in betaine bis(trifluoromethylsulfonyl)imide and its influence on liquid–liquid equilibrium with water

In this study, ionic liquids (ILs) have been proposed as extractants for separation of metals, including rare earth elements. In particular, protonated betaine bis(trifluoromethylsulfonyl)imide ([HBet][TFSI]) exhibits liquid–liquid phase behavior with water that can be tuned by complexation with various metals. Here we show that previously undetected neutral zwitterionic betaine formed during the IL synthesis can affect the phase behaviour. Traditional synthesis of protonated betaine bis(trifluoromethylsulfonyl)imide results in significant amounts of neutral zwitterionic betaine impurity, which dramatically affects phase behavior.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
DOE OSTI2021

Deep Eutectic Solvent Formed by Imidazolium Cyanopyrrolide and Ethylene Glycol for Reactive CO 2 Separations

Solvents made from a reactive ionic liquid, with an imidazolium cation and pyrrolide anion, and ethylene glycol at a wide compositional range were studied for separations of CO 2 at low partial pressures (<<0.1 bar up to 1 bar). Thermal analysis and measurements of viscosity and density show compacting of the liquid upon mixing with enhanced stability achieved by hydrogen bonding. A detailed mechanistic study was performed by IR, quantitative NMR, and ab initio calculations that show significant CO 2 absorption capacity below 5000 ppm of CO 2 in N 2 . Three reversible routes are found that yield carbonate (major product), carboxylate (moderate), and carbamate (minor) species. With CO 2 at 100% RH, bicarbonate along with carbonate species form. The CO 2 -ethlyene glycol reaction complex, the carbonate anion, is stabilized by the hydrogen bonding and Coulombic interactions, thus preventing evaporation of the solvent during regeneration. This study demonstrates a promising approach to designer green solvents for CO 2 separations in open systems such as direct air capture.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
DOE OSTI2017

Interfacial Engineering of Supported Liquid Membranes by Vapor Cross-Linking for Enhanced Separation of Carbon Dioxide

Supported liquid membranes (SLMs) based on ionic liquids (ILs) with not only high gas permeability and selectivity, but also high stability under high pressure, are highly desired for gas separation applications. In this paper, permeable and selective polyamide network (PN) layers are deposited on the surface of SLMs by utilizing the cross-linking reaction of trimesoyl chloride, which was pre-dispersed in the SLMs, and vapor of amine linkers. The vapor cross-linking method makes it easy to control the growth and aggregation of PN layers, owing to the significantly reduced reaction rate, and thereby ensuring the good distribution of PN layers on the surface of SLMs. With rational choice of amine linkers and optimization of vapor cross-linking conditions, the prepared sandwich-like PN@SLMs with ILs embedded homogeneously within polymeric matrices displayed much-improved CO 2 permeability and CO 2 /N 2 selectivity in relation to the pristine SLMs. Moreover, those SLMs with ILs impregnated into porous supports physically displayed improved stability under high pressure after vapor cross-linking, because the PN layers formed on the surface of SLMs help prevent the ILs from being squeezed out. Finally, this interfacial engineering strategy represents a significant advance in the surface modification of SLMs to endow them with promising applications in CO 2 capture.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗