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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 91 records · Page 5
All sourcesNASA NTRSDOE OSTI
DOE OSTI2020

Devices and methods for removing dissolved ions from water using composite resin electrodes

The present invention provides for a device useful or removing dissolved ions from water comprising or configured to comprise composite resin electrodes. The present invention provides for a device useful for removing dissolved ions from water comprising or configured to comprise composite resin electrodes. The present invention also provides for a method for removing dissolved ions from water comprising providing said device, and using it thereof.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
DOE OSTI2026

Electrocoagulation in Water Treatment: Targeted Contaminant Removal and Laboratory Best Practices

Electrocoagulation for water treatment offers many advantages over traditional treatment technologies, including improved energy efficiency and modularity. One challenge with electrocoagulation is the lack of standardization in the methodology and reporting. This review provides a novel contribution by examining the past literature using a uniform metric (charge loading) as a basis for comparison, highlighting the importance of uniform reporting practices in this field. Furthermore, this review provides practical guidance for experimentalists in standardizing the electrocoagulation design and operating procedures. First, we present a comprehensive overview of contaminant-specific electrocoagulation as an electrochemical treatment technology for processing industrial, municipal, and agricultural water, with a focus on aluminum and iron electrocoagulation. We detail the fundamental mechanisms that allow for constituent removal during pretreatment. Specifically, we highlight electrocoagulation’s potential for organics, metalloids, microbes, and hardness remediation, examining the optimal removal conditions in terms of charge loading and current density. We conclude this work with some experimental best practices for lab-scale electrocoagulation experiments.

aluminum↗
DOE OSTI2022

Mass removal efficiencies in water and consequences after a river diversion into coastal wetlands: second thoughts

Abstract Salinity control, nutrient additions, and sediment supply were directly or indirectly the rationale for a $220 million coastal wetland restoration project (Davis Pond River Diversion) that began in 2002. We sampled Mississippi River water going in and out of the receiving basin from 1999 to 2018 to understand why wetland loss increased after it began. There was a reduction in inorganic sediments, nitrogen (N), and phosphorus (P) concentrations within the ponding area of 77%, 39% and 34%, respectively, which is similar to that in other wetlands. But the average sediment accumulation of 0.6 mm year −1 inadequately balances the present-day 5.6 mm year −1 sea level rise or the 7.9 ± 0.13 mm year −1 accretion rates in these organic soils. Nutrients added likely reduced live belowground biomass and soil strength, and increased decomposition of the organic matter necessary to sustain elevations. The eutrophication of the downstream aquatic system from the diversion, principally by P additions, increased Chl a concentrations to a category of ‘poor’ water quality. We conclude that this diversion, if continued, will be a negative influence on wetland area and will eutrophy the estuary. It is a case history example for understanding the potential effects arising from proposed river diversions.

Turner, R. Eugene (ORCID:0000000307767506)↗
DOE OSTI2022

Harmonizing solar induced fluorescence across spatial scales, instruments, and extraction methods using proximal and airborne remote sensing: A multi-scale study in a soybean field

Solar-induced chlorophyll fluorescence (SIF) has been widely used to track vegetation photosynthesis at different scales ranging from in-situ measurements to satellite products. Airborne platforms sample SIF data at a spatial scale intermediate between in-situ and satellite, matching that of ground measurement (e.g. flux tower footprints and other field sampling), enabling us to explore causes of SIF variation and validate satellite-based SIF products. However, harmonizing SIF across sensors and platforms (correcting for systematic errors to yield a consistent, comparable SIF product) is challenging because SIF can be retrieved in different absorption windows, with different instruments and methods complicating the comparison between different observational levels (i.e., ground, airborne, satellites) and between sites equipped with different instruments with varying optical properties (spectral resolution and sampling intervals, spatial resolution). Additionally, the spatial and temporal variability of atmospheric properties can influence the retrieval of the weak SIF signal. Because of these complications, direct comparisons of airborne and ground SIF across scales are rarely attempted. Here, in this study, we combined airborne SIF data with simultaneous ‘ground truth’ data collected by stationary and mobile platforms in a soybean field in Nebraska, USA. In this effort, we tested several SIF extraction methods, including Fraunhofer Line Discrimination (FLD), improved Fraunhofer Line Discrimination (iFLD), Spectral Fitting Method (SFM), SpecFit, and a Singular Vector Decomposition (SVD) method. The SpecFit method was sensitive to the 715–740 nm water bands and removing the water bands in the fitting process yielded better agreement between the airborne and ground SIF spectra. Accurate estimation of the ground level downwelling irradiance obtained by ground measurements over a calibration target improved agreement between airborne and ground SIF retrievals at the O 2 A band, and allowed us to derive a SIF dataset with improved agreement across platforms and sampling scales. This experimental approach provided a method for generating comparable SIF signals across instruments, methods and platforms, which is critical to understanding the SIF-GPP relationship at different scales and to cross-validate the diversity of platforms used for satellite products calibration and validation.

54 ENVIRONMENTAL SCIENCES↗
DOE OSTI2024

Water separator for hydrogen steam injected turbine engine

A propulsion system for an aircraft includes a core engine that includes a core flow path where air is compressed in a compressor section, communicated to a combustor section, mixed with a hydrogen based fuel and ignited to generate a core gas flow that is expanded through a turbine section. The propulsion system includes a hydrogen fuel system that is configured to supply hydrogen fuel to the combustor through a fuel flow path, a condenser that is arranged along the core flow path and configured to condense water within the core gas flow, and a separator that includes an inlet, a primary water outlet and an exit that includes a plurality of exit guide vanes for straightening the core gas flow that proceeds through the exit. The exit guide vanes include a secondary water outlet for removing condensed water in the core gas flow that proceeds through the exit.

Terwilliger, Neil J.↗
DOE OSTI2019

Importance of self-interaction-error removal in density functional calculations on water cluster anions

Accurate description of the excess charge in water cluster anions is challenging for standard semi-local and (global) hybrid density functional approximations (DFAs). Using the recent unitary invariant implementation of the Perdew–Zunger self-interaction correction (SIC) method using Fermi-Löwdin orbitals, we assess the effect of self-interaction error on the vertical detachment energies of water cluster anions with the local spin density approximation (LSDA), Perdew–Burke–Ernzerhof (PBE) generalized gradient approximation, and the strongly constrained and appropriately normed (SCAN) meta-GGA functionals. Our results show that for the relative energies of isomers with respect to reference CCSD(T) values, the uncorrected SCAN functional has the smallest deviation of 21 meV, better than that for the MP2 method. The performance of SIC-SCAN is comparable to that of MP2 and is better than SIC-LSDA and SIC-PBE, but it reverses the ordering of the two lowest isomers for water hexamer anions. Removing self interaction error (SIE) corrects the tendency of LSDA, PBE, and SCAN to over-bind the extra electron. The vertical detachment energies (VDEs) of water cluster anions, obtained from the total energy differences of corresponding anion and neutral clusters, are significantly improved by removing self-interaction and are better than the hybrid B3LYP functional, but fall short of MP2 accuracy. Removing SIE results in substantial improvement in the position of the eigenvalue of the extra electron. The negative of the highest occupied eigenvalue after SIC provides an excellent approximation to the VDE, especially for SIC-PBE where the mean absolute error with respect to CCSD(T) is only 17 meV, the best among all approximations compared in this work.

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

Engineering Scale Drying of Aluminum-Clad Spent Nuclear Fuel: Experiment Report

Engineering-scale tests were performed to evaluate the relative effectiveness of forced gas and vacuum-drying processes on aluminum-clad spent nuclear fuel (ASNF) in preparation for extended dry storage. Drying models were developed to improve confidence in the likely range of conditions at the start of dry storage and to understand the factors most significant to each process. Testing was performed at the Holtec International Forced Helium Dehydration training facility in Camden, New Jersey, by students from the University of South Carolina in collaboration with Idaho National Laboratory. A full-size Type 1a basket, with a full-diameter vessel configuration (based on the Department of Energy standardized canister design), was used in combination with a 10 assembly surrogate ASNF arrangement to provide a proxy for geometry. A resistance heater incorporated in one assembly simulated the influence of 100 W decay heat. This instrumented chamber allowed testing of the removal of bulk water, physisorbed water, and chemisorbed water over a range of operating parameters with either drying process. Thick oxide films were grown on aluminum test plates to mimic the ASNF surface chemistry. These one-use test plates were housed within select assemblies during drying. Post-test analysis of these plates gave a measure of the moisture removed during each test, which was compared to a control. Instrumentation provided detailed thermal, humidity, and gas or pressure data relevant to each test. Model simulations generally compared favorably to instrument data for the tests. While both processes were able to remove bulk water, removal of chemisorbed water was shown to depend heavily on local temperature. To the disadvantage of vacuum drying, operations approaching or exceeding 220°C achieved consistently more dehydroxylation.

11 NUCLEAR FUEL CYCLE AND FUEL MATERIALS↗
DOE OSTI2020

Superselective Removal of Lead from Water by Two-Dimensional MoS 2 Nanosheets and Layer-Stacked Membranes

Point-of-use (POU) devices with satisfactory lead (Pb 2+ ) removal performance are urgently needed in response to recent outbreaks of lead contamination in drinking water. This study experimentally demonstrated the excellent lead removal capability of two-dimensional (2D) MoS 2 nanosheets in aqueous form and as part of a layer-stacked membrane. Among all materials ever reported in the literature, MoS 2 nanosheets exhibit the highest adsorption capacity (740 mg/g), and the strongest selectivity/affinity toward Pb 2+ with a distribution coefficient K d that is orders of magnitude higher than that of other lead adsorption materials (5.2 × 10 7 mL/g). Density functional theory (DFT) simulation was performed to complement experimental measurements and to help understand the adsorption mechanisms. The results confirmed that the cation selectivity of MoS 2 follows the order Pb 2+ > Cu 2+ >> Cd 2+ > Zn 2+ , Ni 2+ > Mg 2+ , K + , Ca 2+ . The membrane formed with layer-stacked MoS 2 nanosheets exhibited a high water flux (145 L/m 2 /h/bar), while effectively decreasing Pb 2+ concentration in drinking water from a few mg/L to less than 10 μg/L. The removal capacity of the MoS 2 membrane is a few orders of magnitude higher than that of other literature-reported membrane filters. Therefore, the layer-stacked MoS 2 membrane has great potential for POU removal of lead from drinking water.

54 ENVIRONMENTAL SCIENCES↗
DOE OSTI2026

Surface Hydroxyls of Imogolite Nanotubes Drive Distinct Structures and Mobility Differentiation of Nanoconfined Water

Abstract Nanoconfined fluids, particularly water, govern subsurface geochemistry, yet the molecular-level mechanisms by which mineral surfaces dictate confined water structure and mobility remain poorly resolved. Here, we combine solution- and solid-state proton (1H) NMR spectroscopy, NMR relaxometry, modulated-gradient spin–echo (MGSE) NMR diffusometry, infrared spectroscopy, and molecular dynamics simulations to demonstrate that surface hydroxyls drive the structural and dynamic differentiation of water in imogolite nanotubes. In saturated suspensions, we observe the coexistence of distinct water 1H environments, each exhibiting significantly reduced mobility, which we attribute to strong interactions with the imogolite surfaces. As more mobile water is removed, long-range water diffusivity in the fibrous solid samples slows to 1.6 × 10–10 m2·s–1 while local fluctuations increase to 3.4 × 10–8 m2·s–1, indicating a significant increase in molecular restriction through surface interactions. Together, our experiments reveal three coexisting populations with varied structures and mobilities, all distinct from liquid bulk water. We resolve a persistent solid-like interfacial layer strongly bound to surface hydroxyls, characterized by an unusually short T2 (<1 ms), and a very close effective 1H–1H distance of ∼1.55 Å between water and the inner-surface silanol group. An inner-core population occupying the inner cavity exhibits an intermediate dynamic regime with restricted axial diffusion, while outer-surface water associated with aluminum hydroxyls retains relatively higher mobility. These results experimentally substantiate a hierarchy of water populations in imogolite and show how surface chemistry dictates the structures and dynamics of confined water.

Fleming, Xander B. [Earth and Environmental Scienc↗
DOE OSTI2024

Systems, methods, and compositions for purifying water

Systems for removing one or more contaminants from water are provided that can include a hydrate formation chamber assembly; a contaminated water diffusion assembly within the hydrate formation chamber assembly; a space between a wall of the hydrate formation chamber assembly and the diffusion assembly; and a guest compound conduit configured to provide a guest compound within the space and form a hydrate comprising water and the guest compound. Methods for removing one or more contaminants from water are provided that can include providing a contaminated water mixture and one or more guest compounds; forming a hydrate complex comprising water and the one or more guest compounds; and separating the water from the guest compounds to provide water with less contaminant. Mixtures are also provided that can include a liquid component comprising water and at least one contaminant, and a solid component comprising a hydrate complex. One embodiment of the system provides methods for production of excess electric power as a byproduct of the desalination process.

McGrail, Bernard P.↗
DOE OSTI2024

Trace Adsorptive Removal of PFAS from Water by Optimizing the UiO‐66 MOF Interface

Abstract The confluence of pervasiveness, bioaccumulation, and toxicity in freshwater contaminants presents an environmental threat second to none. Exemplifying this trifecta, per‐ and polyfluoroalkyl substances (PFAS) present an alarming hazard among the emerging contaminants. State‐of‐the‐art PFAS adsorbents used in drinking water treatment, namely, activated carbons and ion‐exchange resins, are handicapped by low adsorption capacity, competitive adsorption, and/or slow kinetics. To overcome these shortcomings, metal–organic frameworks (MOFs) with tailored pore size, surface, and pore chemistry are promising alternatives. Thanks to the compositional modularity of MOFs and polymer–MOF composites, herein we report on a series of water‐stable zirconium carboxylate MOFs and their low‐cost polymer‐grafted composites as C 8 –PFAS adsorbents with benchmark kinetics and “parts per billion” removal efficiencies. Bespoke insights into the structure–function relationships of PFAS adsorbents are obtained by leveraging interfacial design principles on solid sorbents, creating a synergy between the extrinsic particle surfaces and intrinsic molecular building blocks.

Ilić, Nebojša↗
DOE OSTI2022

Advance modification of polyacrylonitrile nanofibers for enhanced removal of hexavalent chromium from water

Hexavalent chromium [Cr(VI)] is a known carcinogenic and mutagenic heavy metal. Its level in drinking water is regulated worldwide to protect public health. This work presents a novel chemical method to modify the polyacrylonitrile (PAN) nanofibers for efficient Cr(VI) removal from water. The PAN nanofibers with an average diameter of 165 nm are produced using the electrospinning technique. Through a 2-step chemical modification process, the amidine polyacrylonitrile (APAN) nanofibers are synthesized by the conversion of nitrile groups [—C≡N] in PAN nanofibers into amidines [—C(N=NH)(NH 2 )]. The attenuated total reflectance Fourier transform (ATR-FTIR) spectroscopy revealed the successful conversion of nitrile groups into amidoximes, resulting in amidoximated polyacrylonitrile nanofibers, and subsequent conversion into amidine functional groups, forming the APAN nanofibers. Greater concentration of hydroxylamine hydrochloride, increased reaction time and temperature yielded higher conversion of nitrile groups into amidoximes to a maximum of 37%. The Cr(VI) uptake by APAN nanofibers was found as a multilayer adsorption process modeled by Freundlich isotherm. The maximum Langmuir Cr(VI) adsorption capacity for APAN nanofibers was found as 225 mg g -1 at pH = 3.0 after 4.0 h exposure duration. The regeneration study revealed the excellent reusability of APAN nanofibers after five adsorption/desorption cycles.

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

Bioleaching to produce clean loblolly pine for thermochemical conversion

Lignocellulosic biomass contains inorganic elements that could induce slagging, ash fouling, and emission of both corrosive and harmful gases during thermochemical conversion. Water leaching pretreatment can remove most of the water-soluble elements, while it has limited industrial applicability due to its ineffectiveness in removing water-insoluble elements. Bioleaching is an alternative pretreatment method which has not been fully studied. In this work, bioleaching by Aspergillus niger strains NRRL 2001, NRRL 3122, and NRRL 567 was conducted to pretreat loblolly pine biomass with added water. Further, the removal of inorganic elements (K, Ca, Mg, and S) by bioleaching with A. niger NRRL 2001 was compared with chemical leaching with citric acid, HCl, and NaOH. It was shown that the pH reduction during bioleaching greatly improved K and Mg leaching to the point comparable to acid leaching, whereas Ca was precipitated by oxalic acid produced by the fungus. Bioleaching was also conducted in manually separated needles and chips components of loblolly pine. Glucose was added at different levels to assist bioleaching. At higher glucose levels, gluconic acid and citric acid were produced during bioleaching, leading to the increase of K, Ca, and Mg removal rates by more than 35%, 180%, and 390%, respectively, from the feedstock as compared with water leaching. Overall, bioleaching greatly improved removal of K, Ca, Mg, but not S from loblolly pine feedstocks as compared with water leaching.

09 BIOMASS FUELS↗
DOE OSTI2026

An Acid-Free, Temperature-Based Cation Contamination Removal Strategy for PEM Water Electrolysis

It is widely understood that the durability and reliability of polymer electrolyte membrane (PEM) water electrolyzers are heavily dependent on feedwater purity, with cation contaminants that originate from incomplete water purification and balance of plant materials significantly harming electrolyzer performance. However, contamination remains a challenge and a common cause of failure at the stack level, indicating the need for strategies to recover the performance of contaminated cells. In this study, we investigate the effects of temperature on the uptake, electrochemical impacts, and removal of contaminant calcium and iron cations. Lower operating temperatures increase the sensitivity of the cell performance to contaminant cations, while also decreasing cation uptake and promoting contaminant removal. Computational charge transfer modelling shows that lower temperature increases the concentration of contaminant at the cathode and facilitates their removal from the cell. By testing single cells under scenarios designed to mimic stack temperature dynamics, we investigate low-temperature operation as an approach to stack-relevant contaminant recovery. Together, these results demonstrate that the low-temperature recovery approach is a promising approach for acid-free contamination recovery for PEM water electrolysis to promote stack reliability and durability.

08 HYDROGEN↗