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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 271 records · Page 15
All sourcesNASA NTRSDOE OSTI
DOE OSTI2024

Assessment of Amine-Based CO2BOLs for Direct Air Capture

Direct air capture (DAC) technologies extract CO 2 from the atmosphere for CO 2 storage, or utilization. Capturing CO 2 from the air is the most expensive application of carbon capture because CO 2 in the atmosphere is very dilute. There are limited number of CO 2 capture technologies for DAC application. This project aims at developing an energy efficient technology for DAC, leveraging two PNNL’s chemistries (solid and liquid CO 2 capture). Three CO 2 capture sorbents consisting of amine based CO 2 BOLs immobilized in mesoporous silica were designed, synthesized, and tested. These sorbents had ~ 19-23 wt.% amine loadings which is lower than typical amine-based silica sorbents. The surface area and pore volumes of these solid supported CO 2 BOLs are lower compared to those of the pristine silica support. The CO 2 capture performance of these materials was significantly lower than the typical silica supported amines due to low amine loading and higher molecular weight with low amine density. These results show that immobilize CO 2 BOLs in silica are not viable materials for removing CO 2 from ambient air. This project also designed, synthesized at tested liquid solvents for DAC application. Solvent properties that is vapor pressure, CO 2 uptake capacity, kinetics, and viscosity for three novel solvents were evaluated. The CO 2 uptake capacity for one of the most promising amine-based solvent BEPBEGDA was the highest at 13.2 wt% corresponding to 97 mol%. The vapor pressure of the BEPBEGDA solvents were very low at 80 °C compared to other solvents making them suitable for DAC application. The effect of humidity on the CO 2 capture performance of these solvents was evaluated which shows that presence of moisture doesn’t have a negative effect on the CO 2 uptake performance but makes it slightly better. The performances of these solvents were slightly below that of the 0.1M NaOH solution tested under similar conditions. Despite of the slightly lower CO 2 uptake, it is expected that these liquid solvents will have lower regeneration temperature and minimum evaporative losses due their low vapor pressure. Future work will focus on optimization of the liquid solvents for DAC application to improve both CO 2 capture efficiency and capacity without viscosity and vapor pressure increase. Testing of these solvents under DAC conditions using a gas liquid contactor that mimic industrial applications is needed. Solvent cost projection, techno-economic analysis and life cycle analysis are required to evaluate economic viability of this technology.

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

Photoreactive Capture and Conversion of Dilute Carbon Dioxide into Synthetic Natural Gas

This study introduces a photoreactive system that integrates the capture of dilute CO 2 streams with their catalytic conversion to synthetic natural gas (CH 4 ), utilizing a Ru nanoparticle (NP)-doped TiO 2 composite loaded with linear polyethylenimine (L-PEI) and enhanced with plasmonic titanium nitride (TiN). This light-driven approach mitigates challenges that have plagued traditional thermal reactive carbon capture (RCC) methods, such as CO 2 slip and amine degradation. We demonstrate that L-PEI enables stable CO 2 capture and conversion, achieving ~70% conversion of captured CO 2 to CH 4 across multiple reaction cycles using nonflammable forming gas (~5% H 2 ) as the reductant. In contrast, branched PEI (B-PEI)-loaded composites exhibited significant catalyst deactivation after several RCC cycles. Scanning transmission electron microscopy (STEM) imaging confirms that significant sintering of the Ru NPs occur in the B-PEI sample under RCC conditions, whereas their size remains stable in more rigid L-PEI composites. Technoeconomic analysis (TEA) estimates that CH 4 production using this system could cost less than $\$$5/kg based on current electrocatalytic H 2 prices. These results represent one of the most promising demonstrations of amine-based RCC employing dilute CO 2 sources to date.

36 MATERIALS SCIENCE↗
DOE OSTI2024

High Selectivity Reactive Carbon Dioxide Capture over Zeolite Dual-Functional Materials

Reactive carbon dioxide capture (RCC) is a process where carbon dioxide (CO 2 ) is captured from a mixed gas stream (such as air) and converted to products without first performing a separation step to concentrate the CO 2 . Here, in this work, zeolite dual-functional materials (ZFMs) are introduced and evaluated for simulated RCC. The studied ZFMs feature high surface area, crystalline, microporous zeolite faujasite (FAU) as the support. Sodium oxide (“Na 2 O”) is impregnated as an effective capture agent capable of scavenging low concentration CO 2 (1,000 ppm). Exchanged and impregnated sodium on FAU chemisorbs CO 2 as carbonates and bicarbonates but does not promote the conversion of sorbed CO 2 to products when heated in hydrogen. The addition of Ru promotes the formation of formates, while the addition of Pt generates carbonyl surface species when heated in hydrogen. The active metal then promotes extremely high selectivity for CO 2 hydrogenation to either methane on Ru catalyst (~150 °C) or carbon monoxide on Pt catalyst (~200 °C) when heated in reducing atmospheres.

36 MATERIALS SCIENCE↗
DOE OSTI2022

A Review: PFAS Adsorption, Sensing, and Remediation with Engineered Nanoporous Materials

Per- and polyfluoroalkyl substances (PFAS) are among the most abundant environmental contaminant species. They are widespread due to uncontrolled industrial and commercial use and have been linked to health risks such as cancer. With rising global concerns about the public health effects of PFAS, there is an incentive to develop strategies for reliable monitoring and effective PFAS removal, particularly in drinking water. Traditional PFAS sensing techniques are inefficient due to long measurement times, high labor input, high costs, and limitations to ex situ analysis. Current commercially available sorbents for PFAS removal generally lack the ability to capture PFAS components rapidly and quantitatively. Furthermore, existing sorbents are notably inefficient in removing the more toxic, smaller PFAS chemical chains. Large-scale applications of these methods tend to be costly and resource-intensive. Pacific Northwest National Laboratory has developed unique strategies for PFAS sensing and removal with capture probe technology that has an affinity for fluorocarbons, including PFAS. For both sensing and removal, the customizable capture probes can target specific PFAS compounds since they used a metal-organic framework (MOF)-based technology that can be fine-tuned and molecularly tailored. This tailoring of the materials enables high PFAS sensitivity, selectivity, and faster uptake. PNNL’s capture probe materials have been developed into a sensing technique based on the interactions of the capture probes with PFAS at the molecular level and further transduced that to a quantifiable electrochemical response. The materials have been integrated into a sensor platform developed by New Jersey Institute of Technology (NJIT). Tunable capture probes with a range of detection sensitivities allow for faster and more sensitive PFAS detection limits as low as what appears to be 0.5 ng/L (compared to the U.S. Environmental Protection Agency health advisory level of 70 ng/L). Customization of the capture probe results in improved sorption capacities (fast kinetics and high capacities) compared to commercial granular activated carbons. This research applied various experimental and modeling tools to improve understanding the molecular level interactions between the sorbents towards PFAS adsorption properties.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
DOE OSTI2023

Assessment of Materials-Based Options for On-Board Hydrogen Storage for Rail Applications

The objective of this project was to evaluate material- and chemical-based solutions for hydrogen storage in rail applications as an alternative to high-pressure hydrogen gas and liquid hydrogen. Three use cases were assessed: yard switchers, long-haul locomotives, and tenders. Four storage options were considered: metal hydrides, nanoporous sorbents, liquid organic hydrogen carriers, and ammonia, using 700 bar compressed hydrogen as a benchmark. The results suggest that metal hydrides, currently the most mature of these options, have the highest potential. Storage in tenders is the most likely use case to be successful, with long-haul locomotives the least likely due to the required storage capacities and weight and volume constraints. Overall, the results are relevant for high-impact regions, such as the South Coast Air Quality Management District, for which an economical vehicular hydrogen storage system with minimal impact on cargo capacity could accelerate adoption of fuel cell electric locomotives. The results obtained here will contribute to the development of technical storage targets for rail applications that can guide future research. Moreover, the knowledge generated by this project will assist in development of material-based storage for stationary applications such as microgrids and backup power for data centers.

08 HYDROGEN↗
DOE OSTI2023

Modification of CO 2 /H 2 O selectivity of polymer for carbon capture materials

Today, the atmospheric carbon dioxide (CO 2 ) concentration is 421ppm, over one hundred ppm higher than it was at any point in the last 800,000 years (NASA, 2023). Multiple strategies are necessary to reduce the presence of carbon dioxide in the atmosphere. Besides limiting CO 2 output, carbon capture technology is essential to reduce the overall amount of CO 2 . The Microencapsulated CO 2 Sorbents (MECS) team at Lawrence Livermore National laboratory has developed technologies that can capture CO 2 inside microcapsules, where it can be temporarily stored and later released. In 2017, the commercial potential of these microcapsules was recognized. The brewing industry only requires about one third of the CO 2 it releases for carbonization and packaging, which Congwang Ye and Lionel Keene learned when they met with leaders of small breweries in Colorado to discuss employing carbon capture microcapsules in their processes to reduce their carbon footprint and production costs (Thomas, 2017). The breweries were interested in the technology, but the existing microcapsules require hydration, which is an expensive process for small brewers. In order to develop the microcapsules so they can be commercialized, it is essential to reduce their water loss to improve efficiency and reduce costs for the customers. One method to resolve this issue is to alter the membrane formulation by adding a material that is known to be hydrophobic to decrease the water permeability of the entire membrane. The goal of this project was to study the effect of dispersing a nanomaterial in the polymer membrane shells of microcapsules on the water vapor and carbon dioxide permeability of the membranes.

36 MATERIALS SCIENCE↗
DOE OSTI2023

Densification and Immobilization of AgI-Containing Iodine Waste Forms Using Spark Plasma Sintering

Here in this study, porous Ag-xerogel (Ag-Xero), Ag-faujasite (Ag-FAU) zeolite, and Ag-mordenite (Ag-MOR) zeolite sorbents were loaded with iodine gas [I 2 (g)] under saturated conditions at 150 °C for 24 h, followed by densification and consolidation into monolithic waste forms using spark plasma sintering (SPS). For Ag-Xero materials, SPS pellets were made with as-loaded samples, while others were made with preheated (PH; 500 °C for 2 h) samples to help with densification. SPS processing was conducted at 50 MPa under different temperatures (T = 200–800 °C) for different times (t = 0.5–30 min), where eleven AgI-Xero samples, five AgI-FAU, and two AgI-MOR separate samples were produced. The primary goal was to look for the optimum processing parameters for each material to yield pellets with high iodine retentions, high densities, and low porosities while preventing AgI decomposition. The Ag-Xero showed the highest iodine loadings (qe = 470 mg g –1 ) compared to Ag-FAU (qe = 368 mg g –1 ) and Ag-MOR (qe = 108 mg g –1 ). Measured iodine concentrations were the highest in AgI-Xero pellets without PH, followed by AgI-Xero with PH, AgI-FAU, and then AgI-MOR. Silver utilization (I/Ag on a mol % basis) values were in the order of AgI-MOR ≈ AgI-Xero (no PH) > AgI-Xero (PH) > AgI-FAU. Chemical durabilities of SPS-densified AgI-Xero (PH) pellets were very favorable, with lower releases than SPS pellets made from AgI-Xero samples without PH. These results show promise for iodine waste form production.

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

Hybrid Absorption–Crystallization Strategies for the Direct Air Capture of CO2 Using Phase-Changing Guanidium Bases: Insights from in Operando X-ray Scattering and Infrared Spectroscopy Measurements

Efforts to limit rising concentrations of CO 2 have motivated the development of negative emission technologies. Direct air capture (DAC) of CO 2 is one of the negative emissions technologies that has been proposed for the direct removal of CO 2 from the atmosphere. Phase-changing bis(iminonoguanidine) (BIG) sorbents have been developed for the direct air capture of CO 2 . These phase changing sorbents, specifically glyoxal-bis(iminoguanidine) (GBIG), involve (1) CO 2 absorption with aqueous amino acid salts, such as K- or Na-glycinate to yield bicarbonate-rich solutions, (2) crystallization of the bicarbonate anions with a BIG solid, which regenerates the amino acid, and (3) solid-state CO 2 release from the carbonate crystals and BIG regeneration. Despite the promising potential of these materials, their structural evolution during the thermal regeneration of the BIG solids, chemical regeneration of the sodium or potassium glycinate solvents, and the crystallization behavior of CO 2 -loaded BIG bicarbonate remain to be evaluated and understood in detail. The aim of this study is to probe these knowledge gaps. In situ wide-angle X-ray Scattering (WAXS) results show that CO 2 and water molecules in GBIG bicarbonate are simultaneously released in a single step during the thermal regeneration of the sorbent at 97 – 134 °C. In situ ATR-FTIR measurements showed that sodium glycinate and GBIG bicarbonate are simultaneously generated when GBIG, glycine, and sodium bicarbonate are reacted. The crystallization of GBIG bicarbonate from GBIG and CO 2 -loaded monoethanolamine (MEA) occurs rapidly in the first 10 min of the reaction, as determined using in situ GI-SAXS measurements. Overall, the insights from these studies are essential for the scalable implementation of CO 2 capture technologies using these phase-changing sorbents.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
DOE OSTI2023

Advanced Structured Adsorbent Architectures for Transformative Carbon Dioxide Capture Performance (Final Report)

Svante is a world leader at using solid sorbents for low-cost Carbon Dioxide (CO 2 ) capture, a technology which is recognized as critical in meeting the dual mandates of energy security/reliability and the mitigation of man-made CO 2 emissions. Svante has been developing proprietary adsorbent material compositions, forming them into structured laminates, developing and optimizing process cycles, and system design for efficient capture of CO 2 from post-combustion flue gases of thermal power plants and industrial facilities. The deployment of first-generation CO 2 capture technology has been significantly hampered by high costs and energy penalties, among other barriers. Second generation CO 2 capture technologies (including the Mark I variant of Svante’s Veloxotherm™ adsorption-based technology), utilizing single adsorbent architecture, show promise for reducing the barriers to deploying CO 2 capture plants in commercially meaningful numbers. The objective of this project was to evaluate the Recipient’s transformational (Mark-II) VeloxoTherm™ Technology via the development and bench-scale testing of an advanced structured adsorbent, including novel Bi-layer, laminated adsorbent structures and segmented beds. Svante selected, synthesized, and characterized tailored solid adsorbents for computational modeling, advanced structured adsorbent development, process simulations, and dynamic bench scale (~1-10 kg/day CO 2 captured) testing using an existing single-bed VeloxoTherm™ Station (VTS) coupled with a natural gas-fired boiler. Segmented beds used the in-house, multi-bed Process Demonstration Unit (PDU) to demonstrate key performance indicators (KPIs), such as recovery, product purity, regeneration energy, and the integrated system's productivity in lifetime analysis. Segmented beds were used at a 1 tonne per day (TPD) unit at an industrial site to provide bench-scale validation of performance in an industrial setting. Svante was developing and optimizing the post-combustion CO 2 adsorption technology architectures, including the Bi-layer and segmented laminated adsorbent structure design, integrated rapid cycle temperature swing adsorption (RC-TSA) cycle, flow path architecture, and adsorbent bed construction and packaging (including gas porting) to progress towards achievement of DOE’s Transformational CO 2 Capture goals of 95% CO 2 purity and a cost of electricity at least 30% lower than a supercritical Pulverized Coal (PC) power plant with CO 2 capture, or approximately $30 per tonne of CO 2 captured ready for demonstration by 2030. The main requirements to reach the DOE target cost of carbon capture below $30/MT using Rapid-Cycling Temperature Swing Adsorption (RC-TSA) are as follows: (1) Increased capacity at different CO 2 concentrations, (2) Increased sorbents cycle life, (3) Increased O 2 resistance, and (4) Decreased steam requirement to extract 1 kg of CO 2 .

20 FOSSIL-FUELED POWER PLANTS↗
DOE OSTI2024

Enhanced CO 2 Adsorption Capacity in Highly Porous Carbon Materials Derived from Melamine-Formaldehyde Resin

Here, the present study explores the synthesis of N-doped carbon materials with large surface porosity using commercial melamine-formaldehyde resin as the precursor and KOH as the activator. The resin was carbonized first and then activated by KOH with varying KOH amount and activation temperature. Notably, the as-obtained sorbents display advanced porosity with the highest surface area and pore volume of 1591 m 2 /g and 0.74 cm 3 /g, respectively, along with high N content ranging from 6.43 to 18.34 wt %. Remarkably, maximum CO 2 capture amounts of 5.42 and 3.52 mmol/g were accomplished at 0 and 25 degrees C, 1 bar for as-synthesized carbons. Systematic studies point out that narrow microporosity is the major factor determining the CO 2 uptake of these carbons under ambient pressure. Furthermore, these sorbents display notable CO 2 selectivity, rapid adsorption kinetics, moderate heat of adsorption, substantial dynamic CO 2 capture capacity, and stable recyclability. These results underscore the potential of melamine-formaldehyde resin-derived N-doped porous carbon as an efficient and versatile adsorbent for CO 2 capture.

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

Plastic Waste Product Captures Carbon Dioxide in Nanometer Pores

We discuss, plastic waste (PW) and increasing atmospheric carbon dioxide (CO 2 ) levels are among the top environmental concerns presently facing humankind. With an ambitious 2050 zero-CO 2 emissions goal, there is a demand for economical CO 2 capture routes. Here we show that the thermal treatment of PW in the presence of potassium acetate yields an effective carbon sorbent with pores width of 0.7–1.4 nm for CO 2 capture. The PW to carbon sorbent process works with single or mixed streams of polyolefin plastics. The CO 2 capacity of the sorbent at 25 °C is 17.0 ± 1.1 wt % (3.80 ± 0.25 mmol g –1 ) at 1 bar and 5.0 ± 0.6 wt % (1.13 ± 0.13 mmol g –1 ) at 0.15 bar, and it regenerates upon reaching 75 ± 5 °C. The CO 2 capture cost from flue gas via this technology is estimated to be <$21 ton –1 CO 2 , much lower than competing CO 2 capture technologies. Hence, this PW-derived carbon material should find utility in the capture of CO 2 from point sources of high CO 2 emissions while providing a use for otherwise deleterious PW.

01 COAL, LIGNITE, AND PEAT↗
DOE OSTI2024

Bench-Scale Development of a Novel Direct Air Capture Technology Using High-Capacity Structured Sorbents

The work performed under this project has resulted into development of a DAC technology utilizing a structured sorbent to capture CO 2 from ambient air with a key innovation of direct Joule heating of the sorbent for CO 2 desorption. A working SMA, fully integrated with an electrically resistive heating layer, high surface area support, and high CO 2 capacity sorbent coated onto a commercial ceramic monolithic substrate, was successfully developed and demonstrated over >200 adsorption-desorption cycles in a high-fidelity bench test unit directly using ambient air. A cordierite-based monolith was selected as a substrate owing to its high surface area, low bulk density, low heat capacity, and commercial availability. Reaction kinetics study conducted during this project led to development of a promoter for the base Na 2 CO 3 sorbent that could be incorporated into the sorbent to enhance to achieve higher CO 2 adsorption/desorption rates, greater working capacity, and reduced regeneration temperature. An accelerated aging study was conducted in a TGA to determine sorbent stability and no degradation in the sorbent performance was observed even after 250 adsorption-desorption cycles. An electrically resistive heating layer was developed with tunable electrical properties. The heating layer was coated onto the selected cordierite substrate. Aging studies performed showed the electrical properties and heating performance was stable after 500 heating and cooling cycles. The collective findings on the selected cordierite substrate, robust heating layer, promoter and sorbent selection were used to synthesize a full, 6”x6” SMA for bench-scale testing. The bench-scale DAC system was constructed to test full size SMAs using real ambient air for adsorption and joule heating for regeneration. After completing shakedown and commissioning of the 1 kg/day of CO 2 capacity DAC bench unit, an extended operation was performed to complete over 230 cycles with the full size SMA. This testing showed no observable degradation in sorbent performance. A detailed process model, TEA and LCA were developed for a conceptual 100,000 TPY CO 2 removal DAC facility. The LCA results show the net CO 2 e emissions from the DAC system are highly dependent on the electricity source. All other factors, including SMA manufacturing, materials for facility enclosure, etc., are minor cost contributors compared to the energy consumption required for CO 2 removal. With the successful development and validation of the SMA for the sustained performance for CO 2 removal from ambient air with joule heated regeneration in this project, a fully integrated 1 TPY bench-scale DAC system is currently in development with the support of DOE/FECM (DE-FE0032243). The project objective is to demonstrate the engineering design of the DAC system to produce a continuous, high purity CO 2 stream from ambient air. This project will address and validate key engineering features of the DAC system including the gas sealing mechanism and panels, enclosure and air contactor design, and automation sequence to achieve continuous CO 2 production.

42 ENGINEERING↗
DOE OSTI2020

Mercury speciation using microcolumns with a direct mercury analyzer (DMA). Development of analytical method for the Savannah River Site liquid system

Mercury in the Savannah River Site (SRS) Liquid Waste System (LWS) exists in various forms, including: a) ionic inorganic mercury, organomercury (e.g., methyl Hg), and other less abundant species dissolved in LWS fluids, b) mercury solids such as oxides, hydroxides, amalgams, sulfides, and sorbed mercury, c) accumulations of dense liquid elemental mercury, and d) vapor phase elemental and organomercury mercury in tank headspace gas and in evaporators. Strategic and proactive management of the estimated 60,000 Kg mercury in the LWS requires deployment of efficient and effective paradigms for sampling and analysis of the total quantity of mercury in the various physical-chemical forms. Scoping tests of selective gas-phase sorbents for mercury speciation were performed to support LWS objectives. This research specifically focused on developing and testing streamlined methods to obtain high-quality analytical results for gaseous mercury species. The proposed methods are straightforward, using small columns (microcolumns) filled with materials that selectively sorb one or more target forms of mercury. Simple differentiation of mercury species and quantification is then achieved using an efficient thermal-desorption-based total mercury analyzer as the final step. Benefits associated with transitioning from multistep procedures such as EPA Methods 245.1, 1630 and 1631to streamlined microcolumn approaches include reduced analysis time, labor, and waste generation. Such transitioning would maximize the value of the current deployment of direct mercury analysis (EPA Method 7473) at SRS. This work has two target end uses: 1) simplifying the analysis steps and reducing costs for liquid samples (e.g., developing a total organic mercury (TOM) method), and 2) providing options for high-quality onsite analysis and rapid turnaround for gas samples in support of SRS LWS industrial hygiene (IH) objectives.

12 MANAGEMENT OF RADIOACTIVE AND NON-RADIOACTIVE W↗
DOE OSTI2024

Porous liquids: an integrated platform for gas storage and catalysis

Porous liquids (PLs) represent a new frontier in materials design, combining the unique features of fluidity in liquids and permanent porosity in solids. By engineering well-defined pores into liquids via designed structure modification techniques, the greatly improved free volume significantly enhances the gas transport and storage capability of PL sorbents. Triggered by the promising applications of PLs in gas separation, PLs are further explored in catalysis particularly to integrate the gas storage and catalytic transformation procedure. This emerging field has demonstrated promising progress to advance catalytic procedures using PLs as catalysts, with performance surpassing that of the pure liquid and porous host counterparts. In this perspective article, the recent discoveries and progress in the field of integrated gas storage and catalysis by leveraging the PL platforms will be summarized, particularly compared with the traditional homogeneous or heterogeneous catalytic procedures. The unique features of PLs endow them with combined merits from liquid and solid catalysts and beyond which will be illustrated first. This will be followed by the unique techniques being utilized to probe the porosity and active sites in PLs and the structural evolution during the catalytic procedures. The catalytic application of PLs will be divided by the reaction categories, including CO 2 -involving transformation, O 2 -involving reaction, H 2 S conversion, hydrogenation reaction, and non-gas involving cascade reactions. In each reaction type, the synthesis approaches and structure engineering techniques of PLs, structure characterization, catalytic performance evaluation, and reaction mechanism exploration will be discussed, highlighting the structure–performance relationship and the advancement benefiting from the unique features of PLs.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗