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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 217 records · Page 12
All sourcesNASA NTRSDOE OSTI
DOE OSTI2023

Influence of residual chlorine on Ru/TiO 2 active sites during CO 2 methanation

Titania-supported ruthenium (Ru/TiO 2 ) is an established catalyst for the hydrogenation of carbon dioxide to methane (Sabatier reaction). Chlorine contamination, owed to the RuCl 3 precursor, is demonstrated to have a detrimental impact on methanation activity. After calcination and reduction the catalyst contains residual chlorine, shown by XPS. An aqueous ammonia wash removes Cl without leaching Ru. The washed catalysts exhibit improvements in CH 4 site-time yields. Low Ru loading catalysts encounter the greatest activity enhancements after washing (~4.5-fold). DFT calculations indicate that chlorine and CO 2 directly compete for adsorption on Ru step sites, with Cl impeding the adsorption of CO 2 at under-coordinated sites and at higher Cl coverages. H 2 -chemisorption/TPR show that Cl removal lowers the onset of low temperature H 2 dissociation on Ru. Finally, DRIFTS provide evidence that the removal of Cl facilitates low temperature dissociative binding of CO 2 , indicated by the formation of surface bound linear CO species.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
DOE OSTI2015

ZnO/perovskite core–shell nanorod array based monolithic catalysts with enhanced propane oxidation and material utilization efficiency at low temperature

Here, a hydrothermal strategy combined with colloidal deposition synthesis was successfully used to grow ZnO/perovskite (LaBO 3 , B=Mn, Co, Ni) core-shell nanorod arrays within three dimensional (3-D) honeycomb cordierite substrates. A facile sonication assisted colloidal wash coating process is able to coat a uniformly dispersed perovskite nanoparticles onto the large scale ZnO nanorod arrays rooted on the channel surfaces of the 3D cordierite substrate achieved by hydrothermal synthesis. Compared to traditional wash-coated perovskite catalysts, an enhanced catalytic performance was observed for propane oxidation with 25°C lower light-off temperature than wash-coated perovskite catalyst of similar LaMnO 3 loading (4.3mg). Temperature programmed reduction and desorption under H 2 and O 2 atmosphere, respectively, were used to study the reducibility and oxygen activity of these core-shell nanorod arrays based monolithic catalysts, revealing a catalytic activity sequence of LaCoO 3 >LaMnO 3 >La 2 NiO 4 at the initial stage of catalytic reaction. The good dispersion and size control in La-based perovskite nanoparticles and their interfaces to ZnO nanorod arrays support may contribute to the enhancement of catalytic performance. Lastly, this work may provide a new type of Pt-group metals (PGM) free catalysts with improved catalytic performance for hydrocarbon oxidations at low temperatures.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Oxidation kinetics of biochar from woody and herbaceous biomass

The goal of this study was to determine oxidation kinetics for biochar produced from fast pyrolysis of various biomass feedstocks. In particular, the role of inherent ash content on the oxidation rate was evaluated. Thermogravimetric analysis (TGA) and fluidized bed combustion experiments were used to explore oxidation kinetics of six fast pyrolysis produced biochars with diverse ash content. Here, the reaction rates varied by a factor of three under chemical kinetic-limited conditions, demonstrating inorganic content impacts oxidation rate. Chemical kinetic rate coefficients were proposed as a function of compositional parameters to determine overall fit and impact. Potassium content was found to have a positive correlation, best describing the differences in the oxidation kinetic rate coefficients. Additionally, feedstocks were subjected to a 1 M HCl acid wash mitigating the catalytic activity of the metals. Acid washed biochars had lower oxidation kinetic rates compared to their unwashed counterparts, indicating the removal of catalytically active metals reduced oxidation rate. Gas composition (CO/CO 2 ) was measured during fluidized bed experiments for both acid-washed and unwashed biochars, which varied between the six biochars. Formation of CO 2 was greatly affected by catalytic metals, finding potassium content to correlate well with a higher percentage of CO 2 formation as compared to CO. Comparison of oxidation rates were made between the two experimental apparatuses to measure the effect of attrition on biochar oxidation.

09 BIOMASS FUELS↗
DOE OSTI2019

Piperazine aerosol mitigation for post-combustion carbon capture

Amine loss as aerosol is still a challenge for reliable long-term operations in amine scrubbing units. While attempts have been made to understand, predict, and mitigate amine aerosol growth in the absorber, demonstration of the mitigation of piperazine (PZ) aerosol has not been published. This paper presents results from a comprehensive emission study using 5 m PZ. The focus of this work is not to validate growth mechanisms, but to provide data from which existing hypotheses can be analyzed. PZ aerosol at the water wash outlet was characterized by Fourier Transform Infrared Spectroscopy (FTIR) and an Electrical Low-Pressure Impactor (ELPI + ). Two mitigation strategies were successfully implemented during episodes of PZ aerosol emission. These episodes resulted from the presence of SO 3 in the flue gas due to periods of sub-optimal SO 3 removal upstream of the CO 2 capture facility. Four weeks of aerosol tests were also run with 0–6 ppm of SO 3 generated and injected into the flue gas to evaluate the resilience of the mitigation strategies. The first approach to aerosol emission mitigation was to remove aerosol nuclei present in the flue gas. The second approach was to run the absorber with flue gas containing varying SO 3 at conditions that accelerate aerosol nuclei growth and collection within the packing. SO 3 control via hydrated lime addition upstream of the absorber eliminated aerosol while higher lean solvent temperature in the absorber and a two-stage water wash configuration were tested to accelerate aerosol nuclei growth and collection. Increasing the lean solvent temperature by 11 °C and using a two-stage water wash resulted in 98% reduction of PZ emissions. Absorber performance at the elevated lean solvent temperature was sustained in the existing packing with solvent intercooling. PZ emissions were managed to less than 1 ppm for extended periods during the pilot plant campaign.

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

High pressure decontamination of building materials during radiological incident recovery

The release of radiological material from a nuclear incident has the potential to cause extensive radiological contamination requiring rapid decontamination. A promising method for rapid remediation is the use of pressure washers to decontaminate building and street surfaces. Pressure washers utilize both physical removal through surface ablation and chemical removal through desorption of bonded radionuclides. To understand the extent that each removal mechanism is present, overall removals, depth profiles, and wash water were analyzed from the pressure washing of various surfaces contaminated with cesium, strontium, and europium. Removals were dependent on surface type with over 80% of the radionuclides removed from concrete, 50-80% from asphalt, and only 20-25% from brick. Generally, the closer the radionuclide was to the surface of the material, the higher the removal, with europium being removed most readily followed by cesium then strontium, though some exceptions were evident. Comparing these removals and depth profiles of radionuclides in non-decontaminated coupons revealed that cesium and europium are mostly removed through surface ablation. Strontium, on the other hand, is desorbed from the surface, especially from brick and asphalt surfaces. Correspondingly, cesium and europium were attached to the particulates that were likely removed with the pressurized water. Strontium was primarily dissolved in the wash water, supporting the observation that the radionuclide is desorbed from each surface. Finally, the faster the surfaces were brought through the high pressure spray, the lower the removals, arising from decreases in both the physical and desorption mechanisms. Overall, pressure washers were concluded to be a promising decontamination method during radiological incident relief. However, the surface and radionuclide identity must be considered when developing proper procedures.

36 MATERIALS SCIENCE↗
DOE OSTI2021

Effect of alloying with Sc, Nb and Zr on reduction-diffusion synthesis of magnetically hard Sm(Fe,Co,Ti) 12 -based monocrystalline powders

Powders of Sm(Fe,Co) 11.2 Ti 0.8 alloys modified with Sc, Nb and Zr, as well as with additional Ti were prepared by reducing mechanically activated raw oxides with Ca metal in the furnace preheated to 990–1250 °C. Expansion of the crystal lattice upon introduction of Nb or additional Ti implies that atoms of these elements replace the smaller Fe atoms in the tetragonal ThMn 12 -type structure. On the other hand, contraction of the lattice upon introduction of Sc or Zr was smaller than what was expected for replacement of the Sm atoms, which suggests that the Sc and Zr atoms replace both the Sm and Fe atoms. Washing away the reduction byproducts expands the crystal lattice of the 1:12 particles and increases their coercivity. The lattice expansion associated with the washing is believed to be caused by interstitial H atoms; more research, however, is needed to establish the mechanism(s) of the washing effect on the coercivity. The earlier reported development of a high coercivity in zirconium-modified monocrystalline particles achieved by increasing the reduction annealing temperature to ≈1200 °C was similarly characteristic of the particles modified with Sc (the coercivity reaches 11.5 kOe) and Nb (8.1 kOe), but not for the particles prepared with additional Ti where the maximum coercivity of 8.3 kOe develops for a lower annealing temperature. Furthermore, it is concluded that Sc, Nb and Zr modify the high-temperature phase equilibria of the Sm(Fe,Co) 11.2 Ti 0.8 alloys allowing for an effective high-temperature processing, whereas the alloy coercivity increases with the synthesis temperature through a different, still unknown mechanism which may involve suppression of the defects specific to the 1:12 crystals.

36 MATERIALS SCIENCE↗
DOE OSTI2019

Understanding the role of Zn 2+ in surfactant-free layered silicate delamination: Exfoliation of magadiite

Here we investigated the effect of Zn 2+ treatment on the exfoliation of layered silicate magadiite, as a model system, to better understand the role of zinc in surfactant-free zeolite exfoliation. Samples of magadiite and ball-milled magadiite were exfoliated via treatment with aqueous Zn(NO 3 ) 2 solution, and the resulting materials were characterized via powder X-ray diffraction, nitrogen physisorption, high-angle annular dark-field scanning transmission electron microscopy, and infrared spectroscopy. Zn 2+ treatment of magadiite increases its external surface area by 40%, while Zn 2+ treatment of ball-milled magadiite increases its external surface area by 109%. Acid-washing removes Zn(O) x (OH) y colloids and further increases external surface area, leading to a total surface area increase of 150% for magadiite after Zn 2+ treatment and acid-washing, and 182% for ball-milled magadiite after Zn 2+ treatment and acid-washing, by exposing surface area that was not accessible after Zn 2+ treatment due to pore blocking. We propose a mechanism of exfoliation to account for these surface-area increases, which involves the Zn(O) x (OH) y colloids growing and forcing layers apart selectively at the grain boundaries. Ball milling not only makes existing grain boundaries more accessible, but it also creates new grain boundaries, resulting in more efficient exfoliation.

36 MATERIALS SCIENCE↗
DOE OSTI2016

Human dermal absorption of chlorinated organophosphate flame retardants; implications for human exposure

Tris-2-chloroethyl phosphate (TCEP), tris (1-chloro-2-propyl) phosphate (TCIPP) and tris-1,3-dichloropropyl phosphate (TDCIPP) are organophosphate flame retardants (PFRs) widely applied in a plethora of consumer products despite their carcinogenic potential. Human dermal absorption of these PFRs is investigated for the first time using human ex vivo skin and EPISKIN™ models. Results of human ex vivo skin experiments revealed 28%, 25% and 13% absorption of the applied dose (500 ng/cm{sup 2}, finite dose) of TCEP, TCIPP and TDCIPP, respectively after 24 h exposure. The EPISKIN™ model showed enhanced permeability values (i.e. weaker barrier), that were respectively 16%, 11% and 9% for TCEP, TCIPP and TDCIPP compared to human ex vivo skin. However, this difference was not significant (P > 0.05). Estimated permeability constants (K{sub p}, cm/h) showed a significant negative correlation with log K{sub ow} for the studied contaminants. The effect of hand-washing on dermal absorption of PFRs was investigated. Washing reduced overall dermal absorption, albeit to varying degrees depending on the physicochemical properties of the target PFRs. Moreover, slight variations of the absorbed dose were observed upon changing the dosing solution from acetone to 20% Tween 80 in water, indicating the potential influence of the dose vehicle on the dermal absorption of PFRs. Finally, estimated dermal uptake of the studied PFRs via contact with indoor dust was higher in UK toddlers (median ΣPFRs = 36 ng/kg bw day) than adults (median ΣPFRs = 4 ng/kg bw day). More research is required to fully elucidate the toxicological implications of such exposure. - Highlights: • Human dermal absorption of PFRs was studied using human ex vivo skin and EPISKIN™. • Absorbed fractions of TCEP, TCIPP and TDCIPP were 28%, 25% and 13% of applied dose. • Permeability constants showed significant negative correlation to log K{sub ow} of PFRs. • Skin washing reduced the overall dermal absorption of target PFRs to varying degrees. • Toddlers are more exposed to PFRs via dermal contact with indoor dust than adults.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
DOE OSTI2016

Submicron R{sub 2}Fe{sub 14}B particles

Mechanochemical synthesis of submicron R{sub 2}Fe{sub 14}B particles with R = Dy, Nd, Pr has been performed successfully via high energy ball milling of rare-earth oxides, iron oxide and boron oxide in the presence of a reducing agent (Ca) and a dispersant material (CaO), followed by annealing at 800 - 900 °C. In the R = Nd system, we were able to fabricate particles embedded in a CaO matrix with coercivity (H{sub c}) of 10.3 kOe after annealing at 900 °C for 5 min. After washing off the dispersant, the H{sub c} was decreased to below 1 kOe because of hydrogen absorption that leads to the formation of the hydrated R{sub 2}Fe{sub 14}BH{sub x} phase that has a lower anisotropy. Upon removal of the hydrogen the coercivity was increased to 3.3 kOe. The average size of the Nd{sub 2}Fe{sub 14}B particles increases from 100 nm in a sample synthesized at 800 °C to 158 nm at 900 °C. The isotropic Dy{sub 2}Fe{sub 14}B particles showed a higher coercivity of 21 kOe in washed samples after annealing at 900 °C for 5 min. An average size of 71 nm is measured in samples synthesized at 800 °C and 107 nm at 900 °C. Fitting the high field M(H) measurements in Nd{sub 2}Fe{sub 14}B to the law of approach to saturation gave values for the magnetocrystalline anisotropy for the washed sample 2.23 × 10{sup 7} erg/cm{sup 3} and for the vacuum annealed sample 4.15 × 10{sup 7} erg/cm{sup 3}, both of which are lower than the bulk values. This would explain the lower values of H{sub c} observed in the particles.

75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND↗
DOE OSTI2013

Leptogenesis with heavy neutrino flavours: from density matrix to Boltzmann equations

Leptogenesis with heavy neutrino flavours is discussed within a density matrix formalism. We write the density matrix equation, describing the generation of the matter-antimatter asymmetry, for an arbitrary choice of the right-handed (RH) neutrino masses. For hierarchical RH neutrino masses lying in the fully flavoured regimes, this reduces to multiple-stage Boltzmann equations. In this case we recover and extend results previously derived within a quantum state collapse description. We confirm the generic existence of phantom terms. However, taking into account the effect of gauge interactions, we show that they are washed out at the production with a wash-out rate that is halved compared to that one acting on the total asymmetry. In the N{sub 1}-dominated scenario they cancel without contributing to the final baryon asymmetry. In other scenarios they do not in general and they have to be taken into account. We also confirm that there is a (orthogonal) component in the asymmetry produced by the heavier RH neutrinos which completely escapes the washout from the lighter RH neutrinos and show that phantom terms additionally contribute to it. The other (parallel) component is washed out with the usual exponential factor, even for weak washout. Finally, as an illustration, we study the two RH neutrino model in the light of the above findings, showing that phantom terms can contribute to the final asymmetry also in this case.

79 ASTRONOMY AND ASTROPHYSICS↗
DOE OSTI2024

Chlamydomonas cells transition through distinct Fe nutrition stages within 48 h of transfer to Fe-free medium

Low iron (Fe) bioavailability can limit the biosynthesis of Fe-containing proteins, which are especially abundant in photosynthetic organisms, thus negatively affecting global primary productivity. Understanding cellular coping mechanisms under Fe limitation is therefore of great interest. We surveyed the temporal responses of Chlamydomonas (Chlamydomonas reinhardtii) cells transitioning from an Fe-rich to an Fe-free medium to document their short- and long-term adjustments. While slower growth, chlorosis and lower photosynthetic parameters are evident only after one or more days in Fe-free medium, the abundance of some transcripts, such as those for genes encoding transporters and enzymes involved in Fe assimilation, change within minutes, before changes in intracellular Fe content are noticeable, suggestive of a sensitive mechanism for sensing Fe. Promoter reporter constructs indicate a transcriptional component to this immediate primary response. With acetate provided as a source of reduced carbon, transcripts encoding respiratory components are maintained relative to transcripts encoding components of photosynthesis and tetrapyrrole biosynthesis, indicating metabolic prioritization of respiration over photosynthesis. In contrast to the loss of chlorophyll, carotenoid content is maintained under Fe limitation despite a decrease in the transcripts for carotenoid biosynthesis genes, indicating carotenoid stability. These changes occur more slowly, only after the intracellular Fe quota responds, indicating a phased response in Chlamydomonas, involving both primary and secondary responses during acclimation to poor Fe nutrition. Overall design: Sampling of Chlamydomonas CC-4532 cells cultivated photoheterotrophically (TAP) under Fe-starvation condition (0 uM Fe-EDTA). Samples were collected at multiple timepoints from biological duplicate cultures after washing in TAP medium lacking Fe. Two time courses were collected. A short time course with t=0 (pre-wash), 0 (post-wash), 5, 10, 15, 30, 60, 120, and 240 min. A long time course with t= 0, 0.5, 1, 2, 4, 8, 12, 24 and 48 hours. Please note that, for long time course, the GSE44611/PRJNA190650 samples were re-used/re-analyzed together with the short time course data: GSM1087792 C.reinhardtii_Fe_Long_0_hours SRX245324 SAMN01924672 GSM1087793 C.reinhardtii_Fe_Long_0.5_hours SRX245325 SAMN01924673 GSM1087794 C.reinhardtii_Fe_Long_1_hours SRX245326 SAMN01924674 GSM1087795 C.reinhardtii_Fe_Long_2_hours SRX245327 SAMN01924675 GSM1087796 C.reinhardtii_Fe_Long_4_hours SRX245328 SAMN01924676 GSM1087797 C.reinhardtii_Fe_Long_8_hours SRX245329 SAMN01924677 GSM1087798 C.reinhardtii_Fe_Long_12_hours SRX245330 SAMN01924678 GSM1087799 C.reinhardtii_Fe_Long_24_hours SRX245331 SAMN01924679 GSM1087800 C.reinhardtii_Fe_Long_48_hours SRX245332 SAMN01924680

Source record↗
DOE OSTI2014

ACTINIDE REMOVAL PROCESS SAMPLE ANALYSIS, CHEMICAL MODELING, AND FILTRATION EVALUATION

Filtration within the Actinide Removal Process (ARP) currently limits the throughput in interim salt processing at the Savannah River Site. In this process, batches of salt solution with Monosodium Titanate (MST) sorbent are concentrated by crossflow filtration. The filtrate is subsequently processed to remove cesium in the Modular Caustic Side Solvent Extraction Unit (MCU) followed by disposal in saltstone grout. The concentrated MST slurry is washed and sent to the Defense Waste Processing Facility (DWPF) for vitrification. During recent ARP processing, there has been a degradation of filter performance manifested as the inability to maintain high filtrate flux throughout a multi-batch cycle. The objectives of this effort were to characterize the feed streams, to determine if solids (in addition to MST) are precipitating and causing the degraded performance of the filters, and to assess the particle size and rheological data to address potential filtration impacts. Equilibrium modelling with OLI Analyzer{sup TM} and OLI ESP{sup TM} was performed to determine chemical components at risk of precipitation and to simulate the ARP process. The performance of ARP filtration was evaluated to review potential causes of the observed filter behavior. Task activities for this study included extensive physical and chemical analysis of samples from the Late Wash Pump Tank (LWPT) and the Late Wash Hold Tank (LWHT) within ARP as well as samples of the tank farm feed from Tank 49H. The samples from the LWPT and LWHT were obtained from several stages of processing of Salt Batch 6D, Cycle 6, Batch 16.

12 MANAGEMENT OF RADIOACTIVE AND NON-RADIOACTIVE W↗
DOE OSTI2014

Waste Isolation Pilot Plant Salt Decontamination Testing

On February 14, 2014, americium and plutonium contamination was released in the Waste Isolation Pilot Plant (WIPP) salt caverns. At the request of WIPP’s operations contractor, Idaho National Laboratory (INL) personnel developed several methods of decontaminating WIPP salt, using surrogate contaminants and also americium ( 241 Am). The effectiveness of the methods is evaluated qualitatively, and to the extent possible, quantitatively. One of the requirements of this effort was delivering initial results and recommendations within a few weeks. That requirement, in combination with the limited scope of the project, made in-depth analysis impractical in some instances. Of the methods tested (dry brushing, vacuum cleaning, water washing, strippable coatings, and mechanical grinding), the most practical seems to be water washing. Effectiveness is very high, and it is very easy and rapid to deploy. The amount of wastewater produced (2 L/m 2 ) would be substantial and may not be easy to manage, but the method is the clear winner from a usability perspective. Removable surface contamination levels (smear results) from the strippable coating and water washing coupons found no residual removable contamination. Thus, whatever is left is likely adhered to (or trapped within) the salt. The other option that shows promise is the use of a fixative barrier. Bartlett Nuclear, Inc.’s Polymeric Barrier System (PBS) proved the most durable of the coatings tested. The coatings were not tested for contaminant entrapment, only for coating integrity and durability.

12 MANAGEMENT OF RADIOACTIVE AND NON-RADIOACTIVE W↗
DOE OSTI2016

Annual Performance Report April 2015 Through March 2016 for the Shiprock, New Mexico, Disposal Site

This annual report evaluates the performance of the groundwater remediation system at the Shiprock, New Mexico, Disposal Site (Shiprock site) for the period April 2015 through March 2016. The Shiprock site, a former uranium-ore processing facility remediated under the Uranium Mill Tailings Radiation Control Act, is managed by the U.S. Department of Energy (DOE) Office of Legacy Management. This annual report is based on an analysis of groundwater quality and groundwater level data obtained from site monitoring wells and the groundwater flow rates associated with the extraction wells, drains, and seeps. Background The Shiprock mill operated from 1954 to 1968 on property leased from the Navajo Nation. Remediation of surface contamination, including stabilization of mill tailings in an engineered disposal cell, was completed in 1986. During mill operation, nitrate, sulfate, uranium, and other milling-related constituents leached into underlying sediments and contaminated groundwater in the area of the mill site. In March 2003, DOE initiated active remediation of groundwater at the site using extraction wells and interceptor drains. At that time, DOE developed a baseline performance report that established specific performance standards for the Shiprock site groundwater remediation system. The Shiprock site is divided into two distinct areas: the floodplain and the terrace. The floodplain remediation system consists of two groundwater extraction wells, a seep collection drain, and two collection trenches (Trench 1 and Trench 2). The terrace remediation system consists of nine groundwater extraction wells, two collection drains (Bob Lee Wash and Many Devils Wash), and a terrace drainage channel diversion structure. All extracted groundwater is pumped into a lined evaporation pond on the terrace. Compliance Strategy and Remediation Goals As documented in the Groundwater Compliance Action Plan, the U.S. Nuclear Regulatory Commission–approved compliance strategy for the floodplain is natural flushing supplemented by active remediation. The contaminants of concern (COCs) at the site are ammonia (total as nitrogen), manganese, nitrate (nitrate + nitrite as nitrogen), selenium, strontium, sulfate, and uranium. The compliance standards for nitrate, selenium, and uranium are listed in Title 40 Code of Federal Regulations Part 192. Regulatory standards are not available for ammonia, manganese, and sulfate; remediation goals for these constituents are either risk-based alternate cleanup standards or background levels. These standards and background levels apply only to the compliance strategy for the floodplain. The compliance strategy for the terrace is to eliminate exposure pathways at the washes and seeps and to apply supplemental standards in the western section.

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

Tank Closure Cesium Removal Project CST Simulant Cesium Batch Contact Kinetics Test Results and Column Performance Predictions

To evaluate the cesium removal capabilities of the caustic-washed R9120-B version of crystalline silicotitanate (CST) ion exchange media from Savannah River Site (SRS) waste during Tank Closure Cesium Removal (TCCR) column processing, batch contact kinetics tests were performed at 23 °C in SRS Average simulant. Cesium loading kinetics data was also collected (in current and previous testing; King, et al., 2018a) using the same simulant for an older CST sample (IE- 911) which was caustic-washed by the vendor many years ago and was recently retrieved from drums stored at SRS. (Note that R9120-B and IE-911 are believed to be identical materials, after the R9120-B was caustic washed by SRNL, and differ only by particle size and manufacturing date, and thus can be considered different batches). Although cesium loading kinetics testing can be conducted more rigorously using dynamic column tests, the batch contact method requires less simulant and considerably less experimental effort. Average percent removal data for batch contact samples for the two CST batches are provided in Table ES-1. Faster cesium uptake was observed with IE-911, although the loading rates for the two media batches were similar. After 5.5 hours of CST contact, 81% cesium removal was observed with R9120-B versus 86% removal with IE-911. Although these differences are small, the trend is consistent across the timed results, with the larger bead material always loading slower. These seemingly small differences in percent removal are believed to have a large impact on the column performance. Cesium loading curves for the two CST batches are provided in Figure ES-1 below. Faster cesium loading with IE-911 CST is presumed to be associated with the smaller average particle diameter (408 μm mean volume diameter) versus R9120-B (572 μm diameter). Cesium loading kinetic data was needed to conduct column performance comparisons (i.e., model predictions) for the two CST batches.

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

Characterization of Hanford LAW Phase 3 Glasses

This report provides analyses of glass compositions, wash solution compositions, and Product Consistency Test (PCT) leachate compositions for a series of simulated low-activity waste (LAW) glasses fabricated at the Pacific Northwest National Laboratory (PNNL). These data will be used in the development of improved property/composition models for LAW glass at Hanford. Chemical analyses were performed on a representative sample of each of the quenched and sulfur saturated glasses to allow for comparisons with the targeted compositions. For some of the quenched glasses, measured concentrations of Cr 2 O 3 , K 2 O, Na 2 O, P 2 O 5 , and ZrO 2 were below the targeted values. For some of the sulfur saturated glasses, the measured concentrations of Al 2 O 3 , Cl - , Cr 2 O 3 , F - , K 2 O, Na 2 O, P 2 O 5 , V 2 O 5 , and ZrO 2 were generally low relative to the targeted values. A comparison of the measured compositions of the quenched and sulfur saturated versions of the study glasses showed that the measured concentrations of Al 2 O 3 , Cl - , and F - were lower for most of the sulfur saturated glasses. The measured Cr 2 O 3 and K 2 O concentrations were markedly lower for the sulfur saturated versions of the glasses as compared to the quenched versions, which may indicate that these elements partitioned to the soluble sulfur salts. A set of modified glasses was received from PNNL later in this study. Chemical analysis showed that these glasses generally met their targeted compositions. The measured SO 3 concentrations were higher for most of the sulfur saturated glasses relative to those of the quenched versions, as expected. Chemical analysis of the wash solutions that resulted from preparation of the sulfur saturated melts identified Cr, K, Na, P, S, and V as the major elements in solution. With the exception of sulfur, this may explain why the measured concentrations of these components in the study glasses were generally below the targeted values. PNNL performed PCTs on quenched and canister centerline cooled (CCC) versions of the study glasses, as well as the modified glasses. The leachates were sent to SRNL for chemical analysis. Minor scatter in the measured values among the triplicate samples for each glass was noted, with significant differences among the triplicate values noted for four of the CCC glasses. Normalized concentration values for some of the study glasses were greater than the 100 g/L maximum (total dissolution), which may indicate an error in the test. It is recommended that PNNL review the performance of the PCTs to determine the cause of these potential outliers and errors. Revision 1 of this report: Corrects an issue with high chromium measurements for the Mod glass compositions and the second set of PCT leachates, Adds data for the Mod glass wash solutions that were unintentionally omitted, Corrects an issue with rounding of the targeted Al 2 O 3 concentrations in the study glasses

12 MANAGEMENT OF RADIOACTIVE AND NON-RADIOACTIVE W↗
DOE OSTI2021

Analysis and Testing of Parsons NGS Solvent Formulation

Three drums containing solvent used during the Next Generation Solvent Test (NGST) conducted by Parsons in 2014-2015 were received at SRNL. After homogenization, samples from each drum were removed, and a composite sample prepared. This composite was analyzed to determine current SRNL characterization method efficacy, and to determine if the 1,3-dicyclohexyl-2- (isotridecyl) guanidine (DCiTG) suppressor could be selectively removed. The results of this work indicate that the titration analytical method currently employed at SRNL is effective at quantitating the DCiTG. The nuclear magnetic resonance (NMR) method at SRNL can detect the DCiTG, as well its amine and urea decomposition products. However, further development work will be required to allow the 1 H NMR method to quantitate these species. A series of three washing tests were performed on composite samples of the solvent. The results show that up to 67% of the DCiTG was removed from the solvent by simple washing, at multiple ratios of solvent: aqueous phase. This may indicate that a simple pathway exists to wash out the DCiTG and reclaim the solvent (~150 gallons) for future use at the Salt Waste Processing Facility (SWPF).

12 MANAGEMENT OF RADIOACTIVE AND NON-RADIOACTIVE W↗
DOE OSTI2023

Study on Electrostatic Separation of Quinoline Insolubles from Coal Tar Pitch

The feasibility of electrical separation in the removal of quinoline insoluble (QI) particles from coal tar pitch (CTP) was experimentally investigated. QI particle involvement prohibits the effective fabrication of high-quality value-added products, such as carbon fibers, from CTP. A substantial and sustainable CTP market exists around the world; therefore, a strong incentive exists to develop a viable technical approach to effectively and economically remove QI particles from CTP. The electrical separation method shows promise to achieve this technical goal (Cao et al., 2012). Even with the given setup (wire- cylinder adapted), critical issues remain to be addressed for this method to be applicable to the CTP: (1) identifying the wash oil used in the original QI separation, (2) understanding the mechanism of QI separation, (3) characterizing the deposit, and (4) identifying the QI. This study integrated a set of experimental and analysis techniques into the electrical separation tests to address the aforementioned issues. Key findings are as follows: 1. Electric current responses: • The electric current level of the CTP–wash oil solution reported by Cao et al. (2012) can be attained by using a mixture of 25% quinoline and 75% toluene for the CTPs examined in this study under the same electrical load condition. • The electric current tends to decrease during the test period because of the decreasing number of charged particles. • The reversed field corresponded to the configuration of electrostatic precipitation for positive corona discharge. The high electric field can result in dielectric breakdown and lead to an abrupt current surge. 2 Deposit response and solvent candidates: • Deposit of particles in CTP mixture can be effectively implemented in a wire-cylinder configuration as proposed and examined in this study. • Deposit depends on the solvents. Among the solvents tested, two- and three-part solvents that included quinoline and ethanol (i.e., 25% quinoline and 75% toluene; 50% quinoline and 50% toluene; and 33% wash oil, 33% BTX, and 34% ethanol) produced the highest deposit weight. • The deposit process examined in this study is derived from the charged particles. An appreciable relation exists between deposit weight and electric charge. 3. QI removal efficiency (RE): • The RE of the electrostatic separation can reach as high as 76.2% for Carbores, and 61.6% for Koppers. • The RE can be further enhanced if the field level increases from 0.16 kV/mm that was used in the current study to 0.23 kV/mm, according to the relation established between the RE and the electric field. 4. Testing of the modeling system: • The motion of particles is originally driven by the charge-based electric force in the cases tested. The solid particle separation mechanism is similar to that of QI deposition in CTP. • The mechanical movement of solid particles can be strongly affected by the gravitational and viscous forces in the electric field. 5. EDS analysis and chemical compositions: • The main chemical composition of deposit QI matches that of as-prepared CTP QI. The deposit QI is derived from the same group of the CTP QI. • In addition to carbon, the QI contains oxygen, sodium, aluminum, silicon, iron, and sulfur. The work for the near future is also discussed.

01 COAL, LIGNITE, AND PEAT↗