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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 235 records · Page 13
All sourcesNASA NTRSDOE OSTI
NASA NTRS2014

Advanced Water Purification System for In Situ Resource Utilization Project

A main goal in the field of In Situ Resource Utilization is to develop technologies that produce oxygen from regolith to provide consumables to an extratrrestrial outpost. The processes developed reduce metal oxides in the regolith to produce water, which is then electrolyzed to produce oxygen. Hydrochloric and hydrofluoric acids are byproducts of the reduction processes, which must be removed to meet electrolysis purity standards. We previously characterized Nation, a highly water selective polymeric proton-exchange membrane, as a filtrtion material to recover pure water from the contaminated solution. While the membranes successfully removed both acid contaminants, the removal efficiency of and water flow rate through the membranes were not sufficient to produce large volumes of electrolysis-grade water. In the present study, we investigated electrodialysis as a potential acid removable technique. Our studies have show a rapid and significant reduction in chloride and fluoride concentrations in the feed solution, while generating a relatively small volume of concentrated waste water. Electrodialysis has shown significant promise as the primary separation technique in ISRU water purification processes.

Technology Portfolio System↗
NASA NTRS2015

Method of Making Lightweight, Single Crystal Mirror

A method of making a mirror from a single crystal blank may include fine grinding top and bottom surfaces of the blank to be parallel. The blank may then be heat treated to near its melting temperature. An optical surface may be created on an optical side of the blank. A protector may be bonded to the optical surface. With the protector in place, the blank may be light weighted by grinding a non-optical surface of the blank using computer controlled grinding. The light weighting may include creating a structure having a substantially minimum mass necessary to maintain distortion of the mirror within a preset limit. A damaged layer of the non-optical surface caused by light weighting may be removed with an isotropic etch and/or repaired by heat treatment. If an oxide layer is present, the entire blank may then be etched using, for example, hydrofluoric acid. A reflecting coating may be deposited on the optical surface.

Bly, Vincent T.↗
NASA NTRS2023

An Improved Hf Vapor Etching Apparatus for Stardust Particle Extraction

Introduction: The NASA Stardust mission captured thousands of particles from the Jupiter-family comet 81P/Wild 2 in a collector composed of aluminum foil and blocks of silica aerogel [1]. To date, most Wild 2 particles available for study are relatively large and coherent particles extracted individually from the ends of hollow, carrot-shaped impact tracks produced during impact into aerogel. However, >65% of the impacting mass can be found in the ‘bulb’ of the track, including nearly all of the <1 μm size fraction [2]. This fraction contains organic-rich material and is likely to include presolar grains, representing a critical opportunity to constrain the organic and presolar inventory of primitive outer solar system materials. However, the small size and susceptibility of this fraction to melting or alteration during capture poses significant analytical challenges. Previous attempts to extract and concentrate fine-grained material from the bulb of Stardust tracks have attempted to develop techniques that efficiently destroy aerogel and leave impactor particles relatively unharmed. The low density and high porosity of silica aerogel makes it more susceptible to attack by etching with hydrofluoric acid (HF) [3] or CF4 plasma ashing [4] than collected cometary silicates. Previous studies of HF vapor etching used HF solutions varying between 5 to 49% and noted that at high concentrations and etch rates, a liquid droplet was produced according to the etching reaction 4HF + SiO2 → SiF4 (g) + 2H2O [3]. SiF4 readily decomposes into HF and silicic acid in water, which has the potential to alter the freed cometary silicates. The plasma ashing technique avoids production of a liquid droplet and minimizes damage to embedded silicates but requires specialized equipment [4]. In this abstract, we present recent improvements to the HF etching procedure with the aim of constructing an etching chamber capable of slowly etching silica aerogel using small quantities of dilute HF. The etching chamber can be assembled using readily available materials.

Stardust↗
DOE OSTI2011

Nanoparticle-based etching of silicon surfaces

A method (300) of texturing silicon surfaces (116) such to reduce reflectivity of a silicon wafer (110) for use in solar cells. The method (300) includes filling (330, 340) a vessel (122) with a volume of an etching solution (124) so as to cover the silicon surface 116) of a wafer or substrate (112). The etching solution (124) is made up of a catalytic nanomaterial (140) and an oxidant-etchant solution (146). The catalytic nanomaterial (140) may include gold or silver nanoparticles or noble metal nanoparticles, each of which may be a colloidal solution. The oxidant-etchant solution (146) includes an etching agent (142), such as hydrofluoric acid, and an oxidizing agent (144), such as hydrogen peroxide. Etching (350) is performed for a period of time including agitating or stirring the etching solution (124). The etch time may be selected such that the etched silicon surface (116) has a reflectivity of less than about 15 percent such as 1 to 10 percent in a 350 to 1000 nanometer wavelength range.

36 MATERIALS SCIENCE↗
DOE OSTI2012

Color stable manganese-doped phosphors

A process for preparing color stable Mn.sup.+4 doped phosphors includes providing a phosphor of formula I; A.sub.x[MF.sub.y]:Mn.sup.+4 I and contacting the phosphor in particulate form with a saturated solution of a composition of formula II in aqueous hydrofluoric acid; A.sub.x[MF.sub.y]; II wherein A is Li, Na, K, Rb, Cs, NR.sub.4 or a combination thereof; M is Si, Ge, Sn, Ti, Zr, Al, Ga, In, Sc, Y, La, Nb, Ta, Bi, Gd, or a combination thereof; R is H, lower alkyl, or a combination thereof; x is the absolute value of the charge of the [MF.sub.y] ion; and y is 5, 6 or 7. In particular embodiments, M is Si, Ge, Sn, Ti, Zr, or a combination thereof. A lighting apparatus capable of emitting white light includes a semiconductor light source; and a phosphor composition radiationally coupled to the light source, and which includes a color stable Mn.sup.+4 doped phosphor.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
DOE OSTI2014

Color stable manganese-doped phosphors

A lighting apparatus capable of emitting white light includes a semiconductor light source; and a phosphor material radiationally coupled to the light source. The phosphor material includes a color-stable Mn.sup.+4 doped phosphor prepared by a process including providing a phosphor of formula I; A.sub.x[MF.sub.y]:Mn.sup.+4 I and contacting the phosphor in particulate form with a saturated solution of a composition of formula II in aqueous hydrofluoric acid; A.sub.x[MF.sub.y]; II wherein A is Li, Na, K, Rb, Cs, NR.sub.4 or a combination thereof; M is Si, Ge, Sn, Ti, Zr, Al, Ga, In, Sc, Y, La, Nb, Ta, Bi, Gd, or a combination thereof; R is H, lower alkyl, or a combination thereof; x is the absolute value of the charge of the [MF.sub.y] ion; and y is 5, 6 or 7. In particular embodiments, M is Si, Ge, Sn, Ti, Zr, or a combination thereof.

36 MATERIALS SCIENCE↗
DOE OSTI2014

Copper-assisted, anti-reflection etching of silicon surfaces

A method (300) for etching a silicon surface (116) to reduce reflectivity. The method (300) includes electroless deposition of copper nanoparticles about 20 nanometers in size on the silicon surface (116), with a particle-to-particle spacing of 3 to 8 nanometers. The method (300) includes positioning (310) the substrate (112) with a silicon surface (116) into a vessel (122). The vessel (122) is filled (340) with a volume of an etching solution (124) so as to cover the silicon surface (116). The etching solution (124) includes an oxidant-etchant solution (146), e.g., an aqueous solution of hydrofluoric acid and hydrogen peroxide. The silicon surface (116) is etched (350) by agitating the etching solution (124) with, for example, ultrasonic agitation, and the etching may include heating (360) the etching solution (124) and directing light (365) onto the silicon surface (116). During the etching, copper nanoparticles enhance or drive the etching process.

36 MATERIALS SCIENCE↗
DOE OSTI2015

Electrochemical system and method for electropolishing superconductive radio frequency cavities

An electrochemical finishing system for super conducting radio frequency (SCRF) cavities including a low viscosity electrolyte solution that is free of hydrofluoric acid, an electrode in contact with the electrolyte solution, the SCRF cavity being spaced apart from the electrode and in contact with the electrolyte solution and a power source including a first electrical lead electrically coupled to the electrode and a second electrical lead electrically coupled to the cavity, the power source being configured to pass an electric current between the electrode and the workpiece, wherein the electric current includes anodic pulses and cathodic pulses, and wherein the cathodic pulses are interposed between at least some of the anodic pulses. The SCRF cavity may be vertically oriented during the finishing process.

36 MATERIALS SCIENCE↗
DOE OSTI2019

Expression of Interest for off-gas system design build

Idaho National Laboratory (INL) and Pacific Northwest National Laboratory (PNNL) are studying a used nuclear fuel reprocessing system that could be used to recycle used nuclear fuel by separating waste fission products from re-useable, valuable uranium that can be used in making new nuclear fuel. This process includes dissolving the mixture of uranium and fission products in a nitric and hydrofluoric acids, then using an organic extraction process to remove and recover the uranium. The waste fission products remain in the acidic aqueous “raffinate” stream.” The fission products in this raffinate waste stream are expected to require stabilization in a vitrified glass waste form for safe disposal. INL and PNNL plan to construct and operate a facility in which to test the performance of the electric melter process that would receive a non-radioactive but chemically similar simulant of this raffinate. This test system will be located at INL in or near Idaho Falls, ID. In the melter, which operates at a temperature of about 1,050 to 1,150oC, the water, nitric acid, and other volatile and semi-volatile materials evolve into an off-gas stream, while the fission products (in this case, non-radioactive simulants of fission products) are melted with glass forming chemicals into a molten glass. Upon cooling, the molten glass provides a durable waste form for long-term disposal. Expressions of interest are requested from companies who would like to receive a request for proposal to design and build this off-gas system. We expect to request proposals and desire to award a contract prior to the end of September 2019.

22 GENERAL STUDIES OF NUCLEAR REACTORS↗
DOE OSTI2019

Protective cathode coatings for lithium-ion batteries

Cathode coatings for lithium ion batteries, cathodes coated with the coatings, and lithium ion batteries incorporating the coated cathodes are provided. The coatings, which are composed of binary, ternary, and higher order metal oxides and/or metalloid oxides, can reduce the hydrofluoric acid (HF)-induced degradation of the electrolyte and/or cathodes, thereby improving the performance of lithium ion batteries, relative to lithium ion batteries that employ bare cathodes.

Aykol, Muratahan↗
DOE OSTI2021

Methods for electropolishing and coating aluminum on air and/or moisture sensitive substrates

Methods for electropolishing and coating aluminum on a surface of an air and/or moisture sensitive substrate, including: in a vessel, submerging the substrate in a first molten salt bath and applying an anodizing current to the substrate at a first temperature to electropolish the surface of the substrate; wherein the first molten salt bath includes one of a first organic salt bath and first inorganic salt bath; wherein, when used, the first organic salt bath includes one of (a) aluminum halide and ionic liquid, (b) a combination of an aluminum halide and halogenatedmethylphenylsulfone (C 6 (H 5−y ,X y )SO 2 CX 3 , where y is a number from 0-5), (c) a combination of an aluminum halide, an ionic liquid, and halogenatedmethylphenylsulfone (C 6 (H 5−y ,X y )SO 2 CX 3 ), and (d) AlF 3 -organofluoride-hydrofluoric acid adduct; wherein, when used, the first inorganic salt bath includes aluminum halide and alkali metal halide; and wherein the anodizing current is 10-30 mA/cm 2 .

Freiderich, John W.↗
DOE OSTI2022

Methods for electropolishing and coating aluminum on air and/or moisture sensitive substrates

Methods for electropolishing and coating aluminum on a surface of an air and/or moisture sensitive substrate, including: in a vessel, submerging the substrate in a first molten salt bath and applying an anodizing current to the substrate at a first temperature to electropolish the surface of the substrate; wherein the first molten salt bath includes one of a first organic salt bath and first inorganic salt bath; wherein, when used, the first organic salt bath includes one of (a) aluminum halide and ionic liquid, (b) a combination of an aluminum halide and halogenatedmethylphenylsulfone (C 6 (H 5-y ,X y )SO 2 CX 3 , where y is a number from 0-5), (c) a combination of an aluminum halide, an ionic liquid, and halogenatedmethylphenylsulfone (C 6 (H 5-y ,X y )SO 2 CX 3 ), and (d) AlF 3 -organofluoride-hydrofluoric acid adduct; wherein, when used, the first inorganic salt bath includes aluminum halide and alkali metal halide; and wherein the anodizing current is 10-30 mA/cm 2 .

Freiderich, John W.↗
DOE OSTI2013

Study on the Volatility of Cesium in Dry Ashing Pretreatment and Dissolution of Ash by Microwave Digestion System - 13331

Based on the regulation of the activity concentration of Cs-137, Co-58, Co-60, Fe-55, Ni-59, Ni-63, Sr-90, Nb-94, and Tc-99, and the total alpha from the radioactive waste acceptance criteria, the measurement of the activity concentration of these nuclides in low and intermediate levels of radioactive waste such as in paper, cotton, vinyl and plastic samples was investigated. A dry ashing method was applied to obtain a concentration effect of the samples. Owing to the temperature dependence of the volatility for cesium, the temperature of 300 to 650 deg. C was examined. It was found that 450 deg. C is the optimum dry ashing temperature. After dry ashing, the produced ash was dissolved with HNO{sub 3}, HCl, and HF by a high-performance microwave digestion system. The ash sample, for the most part, was completely dissolved with 10 mL of HNO{sub 3}, 4 mL of HCl, and 0.25 mL of HF by a high-performance microwave digestion system using a nova high temperature rotor at 250 deg. C for 90 min until reaching 0.2 g. To confirm the reliability of cesium loss after the performance of the dry ashing procedure, a cesium standard solution for AAS and a Cs-137 standard solution for gamma spectrometry were added to a paper towel or a planchet of stainless steel, respectively. Cesium was measured by AAS, ICP-MS, and gamma spectrometry. The volatility of cesium did not occur until 450 deg. C ashing. (authors)

12 MANAGEMENT OF RADIOACTIVE AND NON-RADIOACTIVE W↗
DOE OSTI2017

Facile Separation of Sr-90, Fe-55, Nb-94, Ni-59,63 with Large Amount of Ca by Controlled pH Precipitation - 17190

it is important to manage low-and intermediate-level radioactive wastes from nuclear power plants due to a permanent disposal. According to the Nuclear Safety and Security Commission (NSSC), among all the regulatory radionuclides, a few radionuclides from the fission products and corrosion products such as Sr-90, Fe-55, Nb-94, Ni-59,63 which emit low-energy x-ray and beta radiation. Thus, it is necessary to separate beta-emitting nuclides individually. For that reason, KAERI has established analytical procedures which can separate Sr-90, Fe-55, Nb-94, Ni-59,63 from radioactive waste samples. However, when radioactive wastes contain large amount of Ca (above 300 mg), it is not easy to recover the target radionuclides because high concentration of Ca has a strong influence on the effective analyses. In order to combat this problem, there was an attempt to make the precipitate as CaF{sub 2} by using hydrofluoric acid. However, this way had a limitation; Fe-55, Nb-94 were precipitated as fluoride compounds as well as Ca. In this study, we have focused on developing a separation procedure stage by stage in the radioactive wastes with Sr-90, Fe-55, Nb-94, Ni-59,63 and large amount of Ca (1500 mg). The detailed steps are described below; (1) Separation of Fe-55, Nb-94, Ni-59,63 as metal hydroxide precipitates: low solubility product constant (Ksp) between pH 6 and pH 10. (2) Selective elimination of Ca-oxalate complex under strong acidic conditions. Consequently, all the metal sources were sequentially separated and quantitatively recovered by inductively coupled plasma atomic emission spectrometric (ICP-AES) analysis, the recovery is as follows; Sr-90 (3 mg): 89.47±5.48%, Fe-55 (20 mg): 99.80±3.19%, Nb-94 (20 mg): 97.45±2.42%, Ni-59,63 (2 mg): 83.59±15.31%, Ca (1500 mg): 85.32±6.38%, respectively. This methodology will help us separation of radioactive wastes efficiently if apply properly. (authors)

07 ISOTOPE AND RADIATION SOURCES↗
DOE OSTI2016

High-resolution Groundwater Investigation at a FUSRAP Site with an Aging Water-supply Infrastructure: Former Harshaw Chemical Company, Ohio - 16146

The Former Harshaw Chemical Company (HCC) Site is located in Cleveland, Ohio, approximately 5 kilometers (km) (3 miles) south of downtown Cleveland, in an industrialized area adjacent to the Cuyahoga River and Big Creek. Developed site parcels include former production areas with legacy buildings, former production area foundations, parking areas associated with previously demolished buildings, and re-developed privately-owned commercial properties. The HCC Site was initially developed 1905 and commercially manufactured chemical solvents, metal salts, fluorides, hydrofluoric acids, and other chemical products. HCC began production activities for the Manhattan Engineer District (MED) in late 1942 in support of the United States' early atomic weapons program. The primary process conducted by the HCC consisted of the refining of uranium oxide to produce several uranium-bearing materials, including uranium hexafluoride (UF{sub 6}), uranium tetrafluoride (UF{sub 4}), and uranium tetrachloride (UCl{sub 4}). The HCC also conducted numerous chemical and radiological research and production activities for the MED and later for the Atomic Energy Commission (AEC). Groundwater and soil contamination resulting from these activities is characterized in the site Remedial Investigation Report (USACE 2009) and primarily found near the G-1 process building. A Feasibility Study (USACE 2012) evaluated soil remediation alternatives and their potential impacts to future groundwater conditions. Since there is no groundwater pathway in the assumed industrial future land use, groundwater evaluations are intended to demonstrate that further degradation of groundwater will not occur after potential soil remediation. Total uranium is the primary MED-based groundwater contaminant and was numerically simulated using a site-specific groundwater flow and transport model. Remedial results are judged in terms of no significant impact, significant positive impact (i.e., significantly decreased extent of contamination), or significant negative impact (i.e., significantly increased extent of contamination). A complicating factor in the groundwater simulation and decision-making process for this site is the existence of municipal water-line leakage on and around the site. This aging infrastructure, in conjunction with the generations of modifications, promoted leakage and fresh-water contact with contaminated soils. To optimize the groundwater conceptual site model for numerical model updates, a high-density groundwater well network was installed in conjunction with the demolition of the G-1 building. The results of the detailed groundwater investigation, coincident soil sampling, utility-line termination, municipal water-line repairs, water-level collection, and uranium sampling indicates the groundwater is re-equilibrating and will lead to optimal decisions and site remediation. (authors)

12 MANAGEMENT OF RADIOACTIVE AND NON-RADIOACTIVE W↗
DOE OSTI2019

Speciation of Mercury and Heavy Metals in Hg-contaminated Soils from Oak Ridge TN - 19426

Mercury is present in various forms in the environments. Mercuric compounds, Hg(II) are found predominant species in soil and water, while elemental mercury, Hg0 is the major species in the atmosphere, and organo-mercury is present mostly in food-chain. The speciation of Hg is important to understand its mobility, bioavailability in soils, sediments and biota and potential toxicity on human and environmental health. A catastrophic Hg spill occurred at the Y-12 National Security Complex (Y-12 Plant) at the Oak Ridge Reservation of the Department of Energy (DOE) in 1960's that contaminated facilities, soil, sediment, surface water, and groundwater within the boundaries of the Y-12 Plant and the downstream environment along the East Fork Poplar Creek (EFPC) at the city of Oak Ridge. It is estimated that 350,000 kg of Hg was released to the environment. The EFPC floodplain soils were reported to contain predominantly cinnabar (HgS) form, but other inorganic and organic Hg species, including Hg0 , HgCl{sub 2}, Hg{sub 2}Cl{sub 2}, HgO and CH{sub 3}Hg{sup +} have been found within the Y-12 Facility boundaries and the 23-km long contaminated EFPC. Over the last 25 years, Hg fluxes from the Y-12 Plant have been reduced by various remediation efforts, nonetheless Hg concentration in water and fish have not declined due to the persistent leaching of Hg from contaminated floodplain soils and sediments. In this work, we performed total elemental analyses and Hg speciation in the floodplain soils and sediments collected along EFPC in Oak Ridge, TN. The objective of the study was to elucidate the distribution of Hg in floodplain soil fractions and the relation with metals including arsenic, copper, zinc and lead. Total elemental; characterization was performed by ICP-MS analysis after with HNO{sub 3} and HF dissolution. Sequential extractions were carried out to extract water-soluble (F1), cation-exchangeable (F2) fractions and those bound to carbonates (F3), reducible oxides (F4) (Mn-oxides), organic matter (F5), amorphous (F6) and crystalline iron oxides (F7) and the residual fraction (F8) containing elemental Hg, non-cinnabar Hg and humic acid-bound Hg. Preliminary studies were conducted with artificially spiked and incubated soils as well as soils contaminated with enriched {sup 200}Hg isotope. The results indicated that Hg is predominantly associated with organic matter, amorphous iron and crystalline oxides and the residual fraction. The total Hg in the first four fractions (F1, F2, F3, and F4) were about 1% of the total Hg, while Hg was found equally bound to organic matter (F5) and crystalline Fe-oxides (F7) that accounted about 20% of total Hg. The Hg associated with amorphous iron oxides (F6) accounted as much as 26% of the total Hg and non-cinnabar Hg accounted about 24% of total Hg (non-cinnabar Hg). The results also indicated positive correlation for As, Cu, Pb and Zn levels with those of Hg. Most As was associated with amorphous Fe-oxides. Cu and Pb were dominant both in organic matter and amorphous oxide fractions. Zn was mostly bound to amorphous Fe-oxide but significant amount of Zn was also found to be associated with organic matter and crystalline Fe-oxides. (authors)

12 MANAGEMENT OF RADIOACTIVE AND NON-RADIOACTIVE W↗
DOE OSTI2020

Trace Chemical Detection Using Intercalated MXenes as a Signal Enhancing Substrate in Optical Probes

MXenes are 2D materials composed of layered transition metal nitrides or carbides. These materials are synthesized by HF exfoliation from MAX phases (Ti{sub 3}AlC{sub 2}). The 2D nanomaterial was synthesized by the removal of the 'A' element, resulting in a Mxene product (Ti{sub 3}C{sub 2}). MXenes have the general formula M{sub n+1}X{sub n}T{sub x}, where M is an early transition metal, X is Carbon and/or Nitrogen, and T accounts for surface terminated functional groups such as Fluoride, hydroxyl, and oxygen. These materials have very unique properties, similar to graphene, that allows them to be applied in a variety of trace detection techniques including surface-enhanced Raman spectroscopy (SERS). MXenes have also been demonstrated to selectively uptake uranyl ion, UO{sub 2}{sup 2+}. If this property can be combined with SERS or fluorescence detection, it may be possible to use MXenes as the basis for an alternative method to kinetic phosphorescence analysis (KPA) for trace uranyl measurements. Objectives: To confirm that MXene Nano materials are suitable substrates for SERS and sensor development by enhancing Raman signaling. To determine if certain MXene preparation methods yield materials that are more suitable for trace sensing methods. To determine uranyl uptake properties of these MXene materials and test them for analytical signals. Sample Preparation: Preparation of Ti{sub 3}C{sub 2}MXene (at FSU). MXenes were prepared by etching Al from Ti{sub 3}AlC{sub 2} (MAX phase)material. Two etching techniques yield different MXene products: LiF/HCl: Milder reaction, larger MXene flakes. HF: Harsher reaction, smaller flakes, larger layer separation. Products washed to remove etchant, vacuum filtered, and dried. Dried MXene flakes are air-stable. Film preparation for sensor testing (at SRNL): Suspend powder in diH{sub 2}O, purge with Ar, sonicate for 30 min. Centrifuge and collect supernate with suspended particles. Observed LiF-etched Mxene yielded a higher density of particles and darker collected solution. Drop-cast (4 ml) supernate onto slides and dried with Ar. For Rhodamine B (RhB) testing, drop-cast 4 ml drops onto Mxene spots and dried with Ar. Scanning Electron Microscopy conditions: 10 kV Beam energy, high vacuum; Working distance of 8 mm; beam penetration depth appx. 4 microns, beam spot size appx. 2 nanometers. Results: Detection of aluminum correlates with bright spots on image. Presence of aluminum shows that LiF/HCl etching was less thorough than HF etching. Trace Cl detection in LiF images suggests incomplete rinsing. HF has smaller feature size, more layer structure, and increased homogeneity, consistent with expectations. Macroscopic Raman spectroscopy measurements: 532 nm excitation, ∼50 mW with a ∼100 micron spot size (InPhotonics RPB probe). Kaiser Optical Holospec f/1.8 spectrometer with cooled (-60 deg.C) Andor iDus OE420 CCD. LiF 1x supernate showed good signal for trace measurements of Rhodamine B. HF and 1/4x LiF supernates showed little Mxene or Rhodamine B signal. Low deposition densities led to excess background signal from glass slides. For LiF film, response is linear with Rhodamine B concentration over range tested. Will retest with Raman microscope (∼1 micron spot size) to characterize SERS of more dilute LiF and HF etched Mxenes. Conclusions: The LiF etched material was more suitable for macroscopic SERS measurements because it was more concentrated, resulting in a thicker film than the HF etched Mxene and diluted LiF sample. However, the other materials may give greater SERS enhancements, which we hope to determine from measurements with the Raman microscope. From characterization with SEM we concluded that the HF etched Mxene is more uniform/homogenous and has smaller particle size than the LiF etched Mxene. There is still aluminum present in both samples indicating that etching wasn't complete, but the removal of the aluminum was more efficient in the HF method. Path Forward: Observe SERS with Raman microscopy, to obtain better signals for the more diluted samples and be able to compare enhancement effects for the different MXenes. Characterize uranyl sorption into MXene films and test Raman and fluorescence signals. Revisit the etching conditions to improve removal of aluminum. FSU and SRNL will continue to collaborate to create and characterize different Mxene materials and test their usefulness for sensor applications.

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

Depth-resolved sagebrush root metabolomics, rhizosphere microbial communities, and geochemistry at the East River Watershed

This data set consists of results from soil nutrient profile, untargeted metabolomics, mass spec imaging, and amplicon sequencing. Data for soil nutrient profile includes common cations (Ca, Mg, Na, and K etc.) extracted from 3 digesting steps – ammonia acetate (for exchangeable cations), nitric acid (for acid dissolved fraction), and hydrofluoric acid/perchloric acid (HF/HClO4) for whole soil digestion. It also includes concentration of organic carbon, inorganic nitrogen (ammonia and nitrate) and phosphorus (Bray-1 P and nitric acid extract), and total nitrogen and phosphorus. Data for untargeted metabolomics includes metabolomic profile for root exudate/tissues and soil extracts from depths at surface soil to saprolite, that were measured using gas chromatography – mass spectrometry (GC-MS), and liquid chromatography – tandem mass spectrometry (LC-MS/MS). Data for mass spec imaging includes spatial distribution of metabolites that were detected and annotated with Fourier transformation ion cyclotron resonance mass spectrometer (FTICR-MS). Data for amplicon sequencing includes the base paired 16S and ITS ribosomal RNA sequences from Miseq Illumina sequencing. All samples were collected from 2 sampling campaign October 2022 and June 2023. Collectively, these datasets enable a mechanistic evaluation of how nutrient acquisition, especially nitrogen and phosphorus, differs between shallow roots operating in soil and deep roots functioning within the fractured bedrock zone. All files are provided as comma-separated values (CSV) fies (.csv) and (GZIP) file (.gz). The compressed .gz FASTQ files can be read directly in R using the dada2 package as part of the amplicon sequence analysis workflow. This work was supported by the Watershed Function Science Focus Area at Lawrence Berkeley National Laboratory funded by the US Department of Energy, Office of Science, Biological and Environmental Research under Contract No. DE-AC02-05CH11231. This research was performed on a project award 60563 (https://dx.doi.org/10.46936/expl.proj.2022.60563/60008727) from the Environmental Molecular Sciences Laboratory, a DOE Office of Science User Facility sponsored by the Biological and Environmental Research program under Contract No. DE-AC05-76RL01830.

EARTH SCIENCE > AGRICULTURE > SOILS > CARBON↗