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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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All sourcesNASA NTRSDOE OSTI
DOE OSTI2022

Control of Structural Hydrophobicity and Cation Solvation on Interlayer Water Transport during Clay Dehydration

Swelling clay hydration/dehydration is important to many environmental and industrial processes. Experimental studies usually probe equilibrium hydration states in an averaged manner and thus cannot capture the fast water transport and structural change in interlayers during hydration/dehydration. Using molecular simulations and thermogravimetric analyses, we observe a two-stage dehydration process. The first stage is controlled by evaporation at the edges: water molecules near hydrophobic sites and the first few water molecules of the hydration shell of cations move fast to particle edges for evaporation. The second stage is controlled by slow desorption of the last 1–2 water molecules from the cations and slow transport through the interlayers. The two-stage dehydration is strongly coupled with interlayer collapse and the coordination number changes of cations, all of which depend on layer charge distribution. Furthermore, this mechanistic interpretation of clay dehydration can be key to the coupled chemomechanical behavior in natural/engineered barriers.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
DOE OSTI2020

Evolution of Elastic and Mechanical Properties During Fault Shear: The Roles of Clay Content, Fabric Development, and Porosity

Phyllosilicates weaken faults due to the formation of shear fabrics. Although the impacts of clay abundance and fabric on frictional strength, sliding stability, and porosity of faults are well studied, their influence on elastic properties is less known, though they are key factors for fault stiffness. We document the role that fabric and consolidation play in elastic properties and show that smectite content is the most important factor determining whether fabric or porosity controls the elastic response of faults. We conducted a suite of shear experiments on synthetic smectite-quartz fault gouges (10–100 wt% smectite) and sediment incoming to the Sumatra subduction zone. We monitored Vp, Vs, friction, porosity, shear and bulk moduli. We find that mechanical and elastic properties for gouges with abundant smectite are almost entirely controlled by fabric formation (decreasing mechanical and elastic properties with shear). Though fabrics control the elastic response of smectite-poor gouges over intermediate shear strains, porosity is the primary control throughout the majority of shearing. Elastic properties vary systematically with smectite content: High smectite gouges have values of Vp ~ 1,300–1,800 m/s, Vs ~ 900–1,100 m/s, K ~ 1–4 GPa, and G ~ 1–2 GPa, and low smectite gouges have values of Vp ~ 2,300–2,500 m/s, Vs ~ 1,200–1,300 m/s, K ~ 5–8 GPa, and G ~ 2.5–3 GPa. We find that, even in smectite-poor gouges, shear fabric also affects stiffness and elastic moduli, implying that while smectite abundance plays a clear role in controlling gouge properties, other fine-grained and platy clay minerals may produce similar behavior through their control on the development of fabrics and thin shear surfaces.

58 GEOSCIENCES↗
DOE OSTI2023

Low hydrogen solubility in clay interlayers limits gas loss in hydrogen geological storage

Gas intercalation into clay interlayers may result in hydrogen loss in the geological storage of hydrogen; a phenomenon that has not been fully understood and quantified. Here we use metadynamics molecular simulations to calculate the free energy landscape of H 2 intercalation into montmorillonite interlayers and the H 2 solubility in the confined water; in comparison with results obtained for CO 2 . Furthermore, the results indicate that H 2 intercalation into hydrated interlayers is thermodynamically unfavorable while CO 2 intercalation can be favorable. H 2 solubility in hydrated clay interlayers is in the same order of magnitude as that in bulk water and therefore no over-solubility effect due to nanoconfinement is observed – in striking contrast with CO 2 . These results indicate that H 2 loss and leakage through hydrated interlayers due to intercalation in a subsurface storage system, if any, is limited.

58 GEOSCIENCES↗
DOE OSTI2023

Surface Complexation/Ion Exchange Hybrid Model for Radionuclide Sorption to Clay Minerals (M4SF-23LL010301062)

This progress report (Level 4 Milestone Number M4SF-23LL010301062) summarizes research conducted at Lawrence Livermore National Laboratory (LLNL) within the Argillite International Collaborations Activity Number SF-23LL01030106. The activity is focused on our long-term commitment to engaging our partners in international nuclear waste repository research. The focus of this milestone is the establishment of international collaborations for surface complexation modeling and the associated impacts of unlocking larger, community-based datasets. More specifically, we are developing a database framework for Spent Fuel and Waste and Science Technology (SFWST) that is aligned with the Helmholtz Zentrum Dresden Rossendorf (HZDR) sorption database development group in support of the database needs of the SFWST program. In our FY22 effort, we described a detailed analysis of U(VI) sorption to quartz through both traditional surface complexation modeling and through a hybrid ML framework. In FY23, effort was placed on publication of these results and expansion of the LLNL surface complexation and ion exchange database (L-SCIE) in order to assess mineral-based radionuclide retardation under a wider variety of geochemical conditions (e.g., ionic strength, varying electrolyte compositions). Efforts were initiated to expand L-SCIE to include radionuclide surface complexation and ion exchange to clays that are relevant to subsurface geochemical processes occurring at nuclear waste repositories. In particular, a large source of sorption data for clays resides at the Paul Scherrer Institute (PSI) (work primarily by Bradbury and Baeyens) and we initiated discussions on how to retrieve those data and apply FAIR principles to those datasets. In addition to L-SCIE development, two hybrid models that incorporate AI/ML were investigated and compared to discern the most promising approaches for accurate and precise estimations of radionuclide retardation. Key considerations for future model development include (1) the ability to reduce computational burden on determining retardation coefficients for PA and (2) the ability to quantify and predict radionuclide-mineral partitioning at a more efficient, rapid pace due to automated workflows. Upon the careful consideration of the most effective modeling approaches, we are identifying ways to implement these approaches into PA. Ultimately, the data science-based workflows will provide a major incentive for other institutions to adopt a FAIR-formatted, interoperable database. LLNL will play a key role in disseminating sorption data and acting as good data stewards by updating the database in a consistent format and assessing the quality of the newly assimilated data in an organized fashion. To this end, all data and workflows are open access and made available on the LLNL Seaborg research website (https://seaborg.llnl.gov/resources/geochemical-databases-modeling-codes).

38 RADIATION CHEMISTRY, RADIOCHEMISTRY, AND NUCLEA↗
DOE OSTI2021

Mechanical and physical properties of inorganic polymer cement made of iron-rich laterite and lateritic clay: A comparative study

In this work, two different laterites (iron contents of 13.07 and 49.34 wt%, respectively, for lateritic clay, LAC, and iron-rich laterite, LAI) were selected and calcined at 600 °C. The obtained calcined laterites, namely LAI600 and LAC600, were separately mixed with an alkaline solution (silicate modulus of 1.35) or an acidic solution (phosphoric acid solution at pH ≤ 2) for the synthesis of inorganic polymer products. The fabricated products were cured at 20 °C (ambient) and 40 °C (oven). The obtained results showed that the compressive strength of each series of alkaline-based inorganic polymer binder increased with ageing time (7 and 28 days) for room temperature curing, while the reverse trend was noted for oven-cured specimens. The best mechanical performance was obtained when using a phosphoric acid solution, 38 and 52 ± 1 MPa; 62 and 65 ± 1 MPa at 28 days for LAC and LAI respectively. It appeared that a higher iron content within the laterite contributed to an increase in the compressive strength under acidic conditions (LAI (59 MPa) > LAC (48 MPa)) compared to the behavior obtained under alkaline conditions (LAI (6 MPa) < LAC (29 MPa)). Accordingly, the acidic products exhibited a dense structure (with lower porosity) and contained amorphous iron/aluminium phosphate phases such as berlinite (FePO{sub 4}), iron hydrogen phosphate hydrate (Fe{sub 3}H{sub 15}(PO{sub 4}){sub 8·}4H{sub 2}O), ferrowyllieite (AlFe{sub 2}Na{sub 2}(PO{sub 4}){sub 3}) and sodium iron phosphate (Na{sub 3}Fe{sub 2}(PO{sub 4}){sub 3}) arising from the alteration of iron minerals in an acidic medium, confirmed by Mössbauer spectroscopy and electron paramagnetic resonance spectroscopy.

36 MATERIALS SCIENCE↗
DOE OSTI2021

On the use of limestone calcined clay cement (LC3) in high-strength strain-hardening cement-based composites (HS-SHCC)

Highlights: • Use of LC{sup 3} slightly reduces flowability and shortens the setting time of fresh matrices. • Highly polymerized C-A-S-H gel and abundant ettringite benefit flexural strength of LC{sup 3}-matrices. • Use of LC{sup 3} enhances the bond strength between fiber and high-strength matrix. • LC{sup 3}-based HS-SHCC yields similar flexural performance as the composite with Portland cement. High-strength strain-hardening cement-based composites (HS-SHCC) demonstrate excellent mechanical and durability properties. However, high cement content typical to HS-SHCC results not only in high carbon footprint, but also in excessive hydration heat and severe autogenous shrinkage. In this investigation, Limestone Calcined Clay Cement (LC{sup 3}) was used to produce sustainable HS-SHCC. The LC{sup 3} substitution resulted in higher energy consumption during mixing and in shorter setting times of the fresh, plain matrices. Although the LC{sup 3} substitution slightly reduced the compressive strength, the formation of highly polymerized C-A-S-H gel and abundant ettringite benefited the flexural strength of the plain matrices. Additionally, single-fiber pullout experiments showed that the use of LC{sup 3} led to increased fiber-matrix bond strength and pullout energy. Finally, the replacement of Portland cement by LC{sup 3} resulted in HS-SHCC with similar mechanical performance to the reference composite, indicating a high potential for using LC{sup 3} in high-performance cement-based composites.

36 MATERIALS SCIENCE↗
DOE OSTI2021

Strength-promoting mechanism of alkanolamines on limestone-calcined clay cement and the role of sulfate

This paper reports the strength-promoting mechanism of alkanolamines on limestone-calcined clay cement (LC{sup 3}). The hydration kinetics, phase formation and microstructure of LC{sup 3} with triethanolamine (TEA) or triisopropanolamine (TIPA) were investigated. TEA enhanced the strength of LC{sup 3}, while TIPA was effective at 28 days, and a correct sulfate addition promoted their effects. Alkanolamines accelerated the aluminate reaction of LC{sup 3} during early hydration, increased sulfate slowed this reaction by producing more ettringite. TIPA favoured the hydration of ferrite in clinker, not only accelerated the silicate reaction of metakaolin, but also resulted in a rapid limestone reaction. Alkanolamines altered the morphology and chemical composition of the aluminate hydrates and C-A-S-H. Alkanolamines enabled the reduction of porosity of hardened pastes and the increased sulfate further refined them. It was the large pores being induced by TIPA at early ages that were considered to have an adverse impact on the early strength of LC{sup 3}.

36 MATERIALS SCIENCE↗
DOE OSTI2021

3D printing of calcined clay-limestone-based cementitious materials

This paper aims to investigate the influences of high Portland cement substitutions (>60 wt%) by low-grade calcined clay (CC) and limestone (LF) on 3D concrete printability, stiffness evolution and early-age hydration. Results show that, with the same dosage of admixtures (superplasticizer and viscosity modifier), increasing LF and CC content reduced the slump, flowability and initial material flow rate, and significantly improved the buildability of fresh mixtures, which can be attributed to the reduced water film thickness (WFT). Furthermore, the stiffness evolution and SSA{sub total} development up to the first 3 h were accelerated by increasing CC content, which can also be linked to the change of WFT, and consumption of superplasticizer for the dispersion induced by hydration products. Additionally, the dilution effect on compressive strength and hydration caused by the high cement replacement was observed.

36 MATERIALS SCIENCE↗
DOE OSTI2021

Limestone calcined clay cement and concrete: A state-of-the-art review

This article reviews the rapidly developing state-of-the-art literature available on the subject of the recently developed limestone calcined clay cement (LC{sup 3}). An introduction to the background leading to the development of LC{sup 3} is first discussed. The chemistry of LC{sup 3} hydration and its production are detailed. The influence of the properties of the raw materials and production conditions are discussed. The mixture design of concrete using LC{sup 3} and the mechanical and durability properties of LC{sup 3} cement and concrete are then compared with other cements. At the end the economic and environmental aspects of the production and use of LC{sup 3} are discussed. The paper ends with suggestions on subjects on which further research is required.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Lattice modeling of excavation damage in argillaceous clay formations: Influence of deformation and strength anisotropy

This paper presents modeling of mechanical anisotropy in argillaceous rocks using an irregular lattice modeling approach, namely the rigid-body-spring network. To represent the mechanical anisotropy, new schemes are implemented in the modeling framework. The directionality of elastic deformation is resolved by modifying the element formulation with anisotropic elastic properties. The anisotropy of strength and failure characteristics is facilitated by adopting orientation-dependent failure criteria into the failure model. The verification of the improved modeling procedures is performed against theoretical model predictions for unconfined compression tests with various bedding orientations. Furthermore, excavation damage and fracturing processes in rock formations are simulated for different geomechanical configurations, such as rock anisotropy and tectonic heterogeneity. The simulated excavation damage characteristics are realistic and comparable with the actual field observation at a tunnel located in an argillaceous clay formation. The simulation results provide insights into the excavation damage zone phenomena with an explicit representation of fracturing processes.

58 GEOSCIENCES↗
DOE OSTI2020

Designing clay-polymer nanocomposite sorbents for water treatment: A review and meta-analysis of the past decade

Clay-polymer nanocomposites (CPNs) have been studied for two decades as sorbents for water pollutants, but their applicability remains limited. Our aim in this review is to present the latest progress in CPN research using a meta-analysis approach and identify key steps necessary to bridge the gap between basic research and CPN application. Based on results extracted from 99 research articles on CPNs and 8 review articles on other widely studies sorbents, CPNs had higher adsorption capacities for several inorganic and organic pollutant classes (including heavy metals, oxyanions, and dyes, n = 308 observations). We applied principal component analysis, analysis of variance, and multiple linear regressions to test how CPN and pollutant properties correlated with Langmuir adsorption model coefficients. While adsorption was, surprisingly, not influenced by mineral properties, it was influenced by CPN fabrication method, polymer functional groups, and pollutant properties. For example, among the pollutant classes, heavy metals had the highest adsorption capacity but the lowest adsorption affinity. Conversely, dyes had high adsorption affinities, as reflected by the linear correlation between adsorption affinity and pollutant molecular weight. Scaling from ‘basic research’ to ‘technological application’ requires testing CPN performance in real water, application in columns, comparison to commercial sorbents, regeneration, and cost evaluation. However, our survey indicates that of the 158 observations, only 20 compared the CPN's performance to that of a commercial sorbent. We anticipate that this review will promote the design of smart and functional CPNs, which can then evolve into an effective water treatment technology.

42 ENGINEERING↗
DOE OSTI2024

Model Development for Thermal-Hydrology Simulations of a Full-Scale Heater Experiment in Opalinus Clay

Disposal of commercial spent nuclear fuel in a geologic repository is studied. In situ heater experiments in underground research laboratories provide a realistic representation of subsurface behavior under disposal conditions. Here, this study describes process model development and modeling analysis for a full-scale heater experiment in opalinus clay host rock. The results of thermal-hydrology simulation, solving coupled nonisothermal multiphase flow, and comparison with experimental data are presented. The modeling results closely match the experimental data.

12 MANAGEMENT OF RADIOACTIVE AND NON-RADIOACTIVE W↗
DOE OSTI2025

Clay Reimagined: Phyllosilicates as Future Membrane Technologies

Membrane technologies have made critical advances in resource recovery, water purification, and energy systems. However, it is difficult to systematically tune properties of traditional polymer membranes, and researchers have struggled to deliver challenging, advanced separations using these platforms. In recent years, membranes based on 2D materials have drawn attention for molecular-scale separations due to their unique properties, most notably their tunable nanoscale interlayer properties. Among the diverse family of 2D materials, phyllosilicates, a broad class of naturally abundant clay minerals, offer significant advantages in cost and scalability over synthetic 2D materials, positioning them as promising candidates for advanced membrane technologies. Their inherent structural and chemical properties, strategies for tailoring selective transport pathways, and recent advancements across applications including ion separation, water treatment, and energy conversion are discussed. Finally, key challenges and opportunities are outlined to guide future research in leveraging phyllosilicate membranes for high-performance separation technologies.

energy storage and conversion↗
DOE OSTI2024

Modeling gas migration through clay-based buffer material using coupled multiphase fluid flow and geomechanics with stress-dependent gas permeability

A model for gas migration through clay-based buffer material is developed for modeling gas generation and migration associated with deep geologic nuclear waste disposal. The model is based on a multiphase fluid flow and geomechanics simulator that is adapted to consider enhanced gas flow when gas pressure is high enough to approach the confining stress magnitude. A key feature in the model is a direct coupling between gas permeability and stress, through a non-linear stress-dependent permeability function. The model was first tested and calibrated by modelling two different laboratory gas migration tests on Wyoming (MX-80) bentonite samples. The calibrated model was then applied to model gas migration through a bentonite buffer of a large-scale gas injection test (Lasgit) conducted at the Äspö Hard Rock Laboratory in Sweden. Observed preferential gas migration along interfaces (between compacted blocks and along the canister surface) required explicit representation of such interfaces in the model. The model with the stress-dependent gas permeability accurately captured observed experimental responses in terms of gas breakthrough time, peak gas pressure, and cumulative gas flow rates. The calibrated model was finally applied to simulate migration of hydrogen gas generated within a breached nuclear waste canister over 10,000 years, involving migration of much larger gas volumes. For the considered gas generation rate and host rock properties, the generated gas could migrate through the bentonite buffer and released into the surrounding host rock at a maximum gas pressure somewhat higher than the initial total stress, though a significant amount of hydrogen remained within the buffer. This modelling sets the stage for further detailed analysis of the impact of hydrogen gas generation on the long-term performance of nuclear waste repositories.

12 MANAGEMENT OF RADIOACTIVE AND NON-RADIOACTIVE W↗
DOE OSTI2022

Overview of the Morphology and Chemistry of Diagenetic Features in the Clay-Rich Glen Torridon Unit of Gale Crater, Mars

The clay-rich Glen Torridon region of Gale crater, Mars, was explored between sols 2300 and 3007. Here, we analyzed the diagenetic features observed by Curiosity, including veins, cements, nodules, and nodular bedrock, using the ChemCam, Mastcam, and Mars Hand Lens Imager instruments. We discovered many diagenetic features in Glen Torridon, including dark-toned iron- and manganese-rich veins, magnesium- and fluorine-rich linear features, Ca-sulfate cemented bedrock, manganese-rich nodules, and iron-rich strata. We have characterized the chemistry and morphology of these features, which are most widespread in the higher stratigraphic members in Glen Torridon, and exhibit a wide range of chemistries. These discoveries are strong evidence for multiple generations of fluids from multiple chemical endmembers that likely underwent redox reactions to form some of these features. In a few cases, we may be able to use mineralogy and chemistry to constrain formation conditions of the diagenetic features. For example, the dark-toned veins likely formed in warmer, highly alkaline, and highly reducing conditions, while manganese-rich nodules likely formed in oxidizing and circumneutral conditions. We also hypothesize that an initial enrichment of soluble elements, including fluorine, occurred during hydrothermal alteration early in Gale crater history to account for elemental enrichment in nodules and veins. The presence of redox-active elements, including Fe and Mn, and elements required for life, including P and S, in these fluids is strong evidence for habitability of Gale crater groundwater. Hydrothermal alteration also has interesting implications for prebiotic chemistry during the earliest stages of the crater’s evolution and early Mars.

58 GEOSCIENCES↗
DOE OSTI2023

Detection and confirmation of fentanyls in high clay‐content soil by electron ionization gas chromatography‐mass spectrometry

Abstract Detection of illicit drugs in the environment, particularly in soils, often suggests the present or past location of a clandestine production center for these substances. Thus, development of efficient methods for the analysis and detection of these chemicals is of paramount importance in the field of chemical forensics. In this work, a method involving the extraction and retrospective confirmation of fentanyl, acetylfentanyl, thiofentanyl, and acetylthiofentanyl using trichloroethoxycarbonylation chemistry in a high clay‐content soil is presented. The soil was spiked separately with each fentanyl at two concentrations (1 and 10 μg/g) and their extraction accomplished using ethyl acetate and aqueous NH 4 OH (pH ~ 11.4) with extraction recoveries ranging from ~56% to 82% for the high‐concentration (10 μg/g) samples while ranging from ~68% to 83% for the low‐concentration (1 μg/g) samples. After their extraction, residues containing each fentanyl were reacted with 2,2,2‐trichloroethoxycarbonyl chloride (Troc‐Cl) to generate two unique and predictable products from each opioid that can be used to retrospectively confirm their presence and identity using EI‐GC‐MS. The method's limit of detection (MDL/LOD) for Troc‐norfentanyl and Troc‐noracetylfentanyl were estimated to be 29.4 and 31.8 ng/mL in the organic extracts. In addition, the method's limit of quantitation for Troc‐norfentanyl and Troc‐noracetylfentanyl were determined to be 88.2 and 95.5 ng/mL, respectively. Collectively, the results presented herein strengthen the use of chloroformate chemistry as an additional chemical tool to confirm the presence of these highly toxic and lethal substances in the environment.

Valdez, Carlos A.↗
DOE OSTI2022

Index tests for geosynthetic clay liners containing bentonite–polymer composites

The hydraulic conductivity of geosynthetic clay liners (GCLs) containing bentonite–polymer composites (BPCs) is controlled by a pore clogging mechanism related to the swelling of sodium bentonite (NaB) granules and formation of polymer gel in the pore space. Three index testing procedures that are influenced by bentonite swelling and rheology of the polymer gel were evaluated in this study for screening BPC GCLs for hydraulic conductivity: viscosity, liquid limit by fall-cone penetration and active water content. Experiments were conducted using polyacrylamide (PAM) polymer, dry-blended mixtures of PAM and NaB and a BPC from a commercially available GCL. These materials were contacted with inorganic solutions representing leachates from a range of waste containment scenarios. For the BPC that was evaluated, hydraulic conductivities less than 10 -10 m/s were obtained when the viscosity exceeded 220 mPa s and the active water content exceeded 300%. Hydraulic conductivities less than 10 -11 m/s were achieved for viscosity exceeding 350 mPa s, fall-cone liquid limit exceeding 190 and active water content exceeding 300%. Additional testing is needed to assess the generality of these index tests and the identified thresholds when applied to other BPC GCLs and other permeant liquids.

Engineering↗