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At least 91 records · Page 5
All sourcesNASA NTRSDOE OSTI
DOE OSTI2025

Feasibility of carbon foam-based sorbents for the abatement of gaseous mercury and iodine

The U.S. Department of Energy Hanford Site in Washington State is in the process of commissioning the Waste Treatment and Immobilization Plant to process a portion of the 54 million gallons of radioactive and chemical waste from cold war weapon production. Technologies for the capture of volatile species of concern are still being assessed, and new methods and materials are developed as operational and flowsheet mission risks are identified. One such area still being assessed is the abatement efficacy of the Carbon Adsorber units to retain gaseous mercury and 129 I released during processing. It is challenging to predict the mercury chemistry due to the variability of the feed, and different methods/materials are required for the capture of gaseous Hg 0 and Hg II compounds. In this study, the feasibility of using developmental carbon foam (CF) sorbents for the capture of iodine and mercury was assessed using static and dynamic flow testing and compared against a commercially available sorbent, BATII-37. Both CF and CF functionalized with bismuth particles (CF-Bi) chemisorbed iodine, and CF-Bi had similar mercury capture performance to BATII-37 in dynamic flow tests. While species loading concentrations were measurable, limitations in achieving a mass balance prevented a full evaluation of capture efficacy. Nonetheless, the results serve as an important first step in demonstrating the potential for simultaneous iodine and mercury capture.

Hanford site↗
DOE OSTI2021

Previously unaccounted atmospheric mercury deposition in a midlatitude deciduous forest

Significance Direct measurements of atmospheric deposition of gaseous elemental mercury (GEM) over a temperate forest showed a pronounced annual deposition of 25.1 µg ⋅ m −2 , which dominated as a source of mercury. GEM deposition was five times greater than wet deposition and three times greater than litterfall deposition, which has been used as a proxy for GEM deposition until now. Measured GEM deposition is driven by combined plant GEM uptake and underlying forest floor GEM uptake. Global forests may be a much larger global GEM sink than currently assumed, which may explain high mercury levels in soils across forests. Forest mercury mobilizes via watershed runoff and bioaccumulates in aquatic biota, ultimately leading to mercury exposures in wildlife and humans.

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

Tank 50 Simulant Grout and Toxicity Characteristic Leaching Procedure (TCLP) Results for Methyl Mercury Waste Acceptance Criteria (WAC) Limit

Testing of simulated Tank 50 salt solution grout, spiked with methyl mercury (MeHg) and ionic mercury, used the Toxicity Characteristic Leaching Procedure (TCLP) to evaluate leaching performance with respect to Hg and the Waste Acceptance Criteria (WAC) limits for the Saltstone Production Facility (SPF). This report describes the test parameters for simulant preparation and confirmatory analysis, grout preparation, TCLP leach testing and subsequent leachate analyses. These scoping tests were designed to provide an initial evaluation of the effect of increased MeHg and ionic Hg on the TCLP and were requested by Savannah River Remediation LLC (SRR) through a Technical Assistance Request (TAR). It is expected that this preliminary testing will likely lead to future, more detailed, testing involving the mercury (Hg) WAC and Hg limits with respect to the Tank 50 TCLP for mercury. The TCLP concentrations for total Hg have approached 0.06 mg/L in recent years for Tank 50 radioactive solutions containing up to 105 mg/L of Hg in the form of ionic (Hg(I/II), elemental (Hg(0)) and organo-mercury such as MeHg. In discussions with SRR personnel, it was decided for this non-baseline work to target Hg spike concentrations, using predominately MeHg, in the range of 150 to 350 mg/L total Hg to investigate corresponding Hg TCLP leaching behaviors.

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

Literature Review Investigating Adsorbents for Mercury Removal from Salt Batch Feed Material

The Savannah River Site (SRS) Liquid Waste System (LWS) contains mercury that originated from decades of canyon processing where it was used as a catalyst for dissolving aluminum cladding of reactor fuel. Since the start of radioactive operations, the Salt Waste Processing Facility (SWPF) has experienced processing difficulties due to the presence of mercury-laden solids. In response to these challenges, Savannah River National Laboratory (SRNL) has been requested by Savannah River Mission Completion (SRMC)/Salt Waste Processing Facility (SWPF) personnel to perform a literature review to assess the feasibility of chemical strikes to salt waste-containing tanks at the SRS as an option to reduce mercury introduction into SWPF. The literature review should evaluate known technologies and chemistries for decreasing mercury concentration and the anticipated efficacy of each technology on various mercury species known to exist in SRS waste.

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

Estimating Interplanetary Magnetic Field Conditions at Mercury's Orbit From MESSENGER Magnetosheath Observations Using a Feedforward Neural Network

Abstract Mercury's small magnetosphere is embedded in the dynamic and intense solar wind environment characteristic of the inner heliosphere. Both the magnitude and orientation of the interplanetary magnetic field (IMF) significantly influence the solar wind‐magnetospheric interaction at Mercury, driving phenomena such as magnetic reconnection. The MErcury Surface, Space Environment, Geochemistry and Ranging (MESSENGER) spacecraft provided in‐situ magnetic field measurements of the solar wind, the magnetosheath, and the magnetosphere along each orbit. However, it is a challenge to directly assess the IMF's impact on Mercury's plasma environment due to the temporal separation between observations within the solar wind and the magnetosphere, especially in the absence of an upstream monitor. Here, we present a feedforward neural network (FNN) trained on a subset of magnetosheath observations to estimate the strength and orientation of the IMF upstream of the bow shock. Utilizing magnetosheath magnetic field, cylindrical spatial coordinates, and heliocentric distance measurements, the FNN predicts upstream IMF conditions with an score of 0.70 and mean averaged error of 5.3 nT, thereby greatly decreasing the temporal separation between IMF estimates and magnetospheric measurements throughout the MESSENGER mission. This approach yields IMF estimates for all magnetosheath data measured by MESSENGER, providing a useful tool for future investigations of the IMF impact on Mercury's magnetosphere. This method will be integrable with the dual‐spacecraft BepiColombo magnetosheath measurements, providing useful estimates of upstream IMF conditions particularly during the extended periods in which neither spacecraft sample the solar wind. Our results demonstrate the utility of machine learning techniques on advancing space science research.

Bowers, Charles F.↗
DOE OSTI2021

A Compact Gas Liquid Separator for the Spallation Neutron Source Mercury Process Loop

Upgrades at the spallation neutron source (SNS) accelerator at Oak Ridge National Laboratory are underway to double its proton beam power from 1.4 to 2.8 MW. About 2 MW will go to the current first station while the rest will go to the future Second Target Station. The increase of beam power to the first target station is especially challenging for its mercury target. When the short proton beam hits the target, strong pressure waves are generated, causing cavitation erosion and challenging stresses for the target's weld regions. SNS has successfully operated reliably at 1.4 MW by mitigating the pressure wave with the injection of small Helium bubbles into the mercury. To operate reliably at 2 MW, more gas will be injected into mercury to mitigate the pressure wave further. However, the mercury process loop was not originally designed for gas injection, and the accumulation of gas in the pipes is a concern. Due to space constraints, a custom gas liquid separator (GLS) was designed to fit a 90-deg horizontal elbow space in the SNS mercury loop. Simulations and experiments were performed, and a successful design was developed that has the desired efficiency while keeping the pressure losses acceptable.

42 ENGINEERING↗
DOE OSTI2020

Synergistic Effects of a Chalkophore, Methanobactin, on Microbial Methylation of Mercury

Microbial production of the neurotoxin methylmercury (MeHg) is a significant health and environmental concern, as it can bioaccumulate and biomagnify in the food web. A chalkophore or a copper-binding compound, termed methanobactin (MB), has been shown to form strong complexes with mercury [as Hg(II)] and also enables some methanotrophs to degrade MeHg. It is unknown, however, if Hg(II) binding with MB can also impede Hg(II) methylation by other microbes. Contrary to expectations, MB produced by the methanotroph Methylosinus trichosporium OB3b (OB3b-MB) enhanced the rate and efficiency of Hg(II) methylation more than that observed with thiol compounds (such as cysteine) by the mercury-methylating bacteria Desulfovibrio desulfuricans ND132 and Geobacter sulfurreducens PCA. Compared to no-MB controls, OB3b-MB decreased the rates of Hg(II) sorption and internalization, but increased methylation by 5- to 7-fold, suggesting that Hg(II) complexation with OB3b-MB facilitated exchange and internal transfer of Hg(II) to the HgcAB proteins required for methylation. Conversely, addition of excess amounts of OB3b-MB or a different form of MB from Methylocystis strain SB2 (SB2-MB) inhibited Hg(II) methylation, likely due to greater binding of Hg(II). Collectively, our results underscore the complex roles of microbial exogenous metal-scavenging compounds in controlling net production and bioaccumulation of MeHg in the environment. Some anaerobic microorganisms convert inorganic mercury (Hg) into the neurotoxin methylmercury, which can bioaccumulate and biomagnify in the food web. While the genetic basis of microbial mercury methylation is known, factors that control net methylmercury production in the environment are still poorly understood. Here, it is shown that mercury methylation can be substantially enhanced by one form of an exogenous copper-binding compound (methanobactin) produced by some methanotrophs, but not by another. This novel finding illustrates that complex interactions exist between microbes and that these interactions can potentially affect the net production of methylmercury in situ .

54 ENVIRONMENTAL SCIENCES↗
DOE OSTI2021

Dynamical Avenues for Mercury’s Origin. I. The Lone Survivor of a Primordial Generation of Short-period Protoplanets

The absence of planets interior to Mercury continues to puzzle terrestrial-planet formation models, particularly when contrasted with the relatively high derived occurrence rates of short-period planets around Sun-like stars. Recent work proposed that the majority of systems hosting hot super-Earths attain their orbital architectures through an epoch of dynamical instability after forming in quasi-stable, tightly packed configurations. Isotopic evidence seems to suggest that the formation of objects in the super-Earth-mass regime is unlikely to have occurred in the solar system as the terrestrial-forming disk is thought to have been significantly mass deprived starting around 2 Myr after the formation of calcium-aluminum-rich inclusions—a consequence of either Jupiter’s growth or an intrinsic disk feature. Nevertheless, terrestrial-planet formation models and high-resolution investigations of planetesimal dynamics in the gas-disk phase occasionally find that quasi-stable protoplanets with mass comparable to that of Mars emerge in the vicinity of Mercury’s modern orbit. In this paper, we investigate whether it is possible for a primordial configuration of such objects to be cataclysmically destroyed in a manner that leaves Mercury behind as the sole survivor without disturbing the other terrestrial worlds. We use numerical simulations to show that this scenario is plausible. In many cases, the surviving Mercury analog experiences a series of erosive impacts, thereby boosting its Fe/Si ratio. A caveat of our proposed genesis scenario for Mercury is that Venus typically experiences at least one late giant impact.

79 ASTRONOMY AND ASTROPHYSICS↗
DOE OSTI2020

Sorbents for the oxidation and removal of mercury

A promoted activated carbon sorbent is described that is highly effective for the removal of mercury from flue gas streams. The sorbent comprises a new modified carbon form containing reactive forms of halogen and halides. Optional components may be added to increase reactivity and mercury capacity. These may be added directly with the sorbent, or to the flue gas to enhance sorbent performance and/or mercury capture. Mercury removal efficiencies obtained exceed conventional methods. The sorbent can be regenerated and reused. Sorbent treatment and preparation methods are also described. New methods for in-flight preparation, introduction, and control of the active sorbent into the mercury contaminated gas stream are described.

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

Sorbents for the oxidation and removal of mercury

A promoted activated carbon sorbent is described that is highly effective for the removal of mercury from flue gas streams. The sorbent comprises a new modified carbon form containing reactive forms of halogen and halides. Optional components may be added to increase reactivity and mercury capacity. These may be added directly with the sorbent, or to the flue gas to enhance sorbent performance and/or mercury capture. Mercury removal efficiencies obtained exceed conventional methods. The sorbent can be regenerated and reused. Sorbent treatment and preparation methods are also described. New methods for in-flight preparation, introduction, and control of the active sorbent into the mercury contaminated gas stream are described.

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

Sorbents for the oxidation and removal of mercury

A promoted activated carbon sorbent is described that is highly effective for the removal of mercury from flue gas streams. The sorbent comprises a new modified carbon form containing reactive forms of halogen and halides. Optional components may be added to increase reactivity and mercury capacity. These may be added directly with the sorbent, or to the flue gas to enhance sorbent performance and/or mercury capture. Mercury removal efficiencies obtained exceed conventional methods. The sorbent can be regenerated and reused. Sorbent treatment and preparation methods are also described. New methods for in-flight preparation, introduction, and control of the active sorbent into the mercury contaminated gas stream are described.

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

Sorbents for the oxidation and removal of mercury

A promoted activated carbon sorbent is described that is highly effective for the removal of mercury from flue gas streams. The sorbent comprises a new modified carbon form containing reactive forms of halogen and halides. Optional components may be added to increase reactivity and mercury capacity. These may be added directly with the sorbent, or to the flue gas to enhance sorbent performance and/or mercury capture. Mercury removal efficiencies obtained exceed conventional methods. The sorbent can be regenerated and reused. Sorbent treatment and preparation methods are also described. New methods for in-flight preparation, introduction, and control of the active sorbent into the mercury contaminated gas stream are described.

Olson, Edwin S.↗
DOE OSTI2021

Sorbents for the oxidation and removal of mercury

A promoted activated carbon sorbent is described that is highly effective for the removal of mercury from flue gas streams. The sorbent comprises a new modified carbon form containing reactive forms of halogen and halides. Optional components may be added to increase reactivity and mercury capacity. These may be added directly with the sorbent, or to the flue gas to enhance sorbent performance and/or mercury capture. Mercury removal efficiencies obtained exceed conventional methods. The sorbent can be regenerated and reused. Sorbent treatment and preparation methods are also described. New methods for in-flight preparation, introduction, and control of the active sorbent into the mercury contaminated gas stream are described.

Olson, Edwin S.↗
DOE OSTI2022

Extraction of gold, mercury, and lead with TEVA resin from HCl and HNO 3

The extraction behavior of 212 Pb, 197m Hg, and 194 Au on TEVA resin in HCl and HNO 3 solutions was studied with batch uptake, kinetics, and column studies. The uptake of mercury and gold was extremely high from HCl solutions, with maximum k’ >80,000 for both elements. The uptake of mercury was lower in HNO3 than HCl with a maximum k’ of ~ 8,000 in 0.02 M HNO 3 and decreasing uptake at higher concentrations of HNO3, which agrees well with previous work. The batch uptake of gold in HNO 3 was not measured, as it had been reported previously. The uptake of lead on TEVA resin in HCl was low with a maximum k’ of only ~ 90 in 1 M HCl. The uptake of lead in HNO 3 was negligible. The uptake kinetics of gold and mercury were characterized in HCl and HNO 3 solutions and high uptake was seen after ~ 60 s for both elements. Column separations of 212 Pb, 197m Hg, and 194 Au on TEVA resin from HCl and HNO 3 solutions are reported with high yields of mercury and lead, but with high losses of gold, which is retained on the resin. A rapid, high yield separation of 197m Hg from irradiated gold foils is presented with yields of ~ 100% for both elements and a total separation time of < 2 h.

38 RADIATION CHEMISTRY, RADIOCHEMISTRY, AND NUCLEA↗
DOE OSTI2021

SERENA: Particle Instrument Suite for Determining the Sun-Mercury Interaction from BepiColombo

The ESA-JAXA BepiColombo mission to Mercury will provide simultaneous measurements from two spacecraft, offering an unprecedented opportunity to investigate magnetospheric and exospheric particle dynamics at Mercury as well as their interactions with solar wind, solar radiation, and interplanetary dust. The particle instrument suite SERENA (Search for Exospheric Refilling and Emitted Natural Abundances) is flying in space on-board the BepiColombo Mercury Planetary Orbiter (MPO) and is the only instrument for ion and neutral particle detection aboard the MPO. It comprises four independent sensors: ELENA for neutral particle flow detection, Strofio for neutral gas detection, PICAM for planetary ions observations, and MIPA, mostly for solar wind ion measurements. SERENA is managed by a System Control Unit located inside the ELENA box. In the present paper the scientific goals of this suite are described, and then the four units are detailed, as well as their major features and calibration results. Finally, the SERENA operational activities are shown during the orbital path around Mercury, with also some reference to the activities planned during the long cruise phase.

79 ASTRONOMY AND ASTROPHYSICS↗
DOE OSTI2024

Horizontal gene transfer of the Mer operon is associated with large effects on the transcriptome and increased tolerance to mercury in nitrogen-fixing bacteria

Abstract Background Mercury (Hg) is highly toxic and has the potential to cause severe health problems for humans and foraging animals when transported into edible plant parts. Soil rhizobia that form symbiosis with legumes may possess mechanisms to prevent heavy metal translocation from roots to shoots in plants by exporting metals from nodules or compartmentalizing metal ions inside nodules. Horizontal gene transfer has potential to confer immediate de novo adaptations to stress. We used comparative genomics of high quality de novo assemblies to identify structural differences in the genomes of nitrogen-fixing rhizobia that were isolated from a mercury (Hg) mine site that show high variation in their tolerance to Hg. Results Our analyses identified multiple structurally conserved merA homologs in the genomes of Sinorhizobium medicae and Rhizobium leguminosarum but only the strains that possessed a Mer operon exhibited 10-fold increased tolerance to Hg. RNAseq analysis revealed nearly all genes in the Mer operon were significantly up-regulated in response to Hg stress in free-living conditions and in nodules. In both free-living and nodule environments, we found the Hg-tolerant strains with a Mer operon exhibited the fewest number of differentially expressed genes (DEGs) in the genome, indicating a rapid and efficient detoxification of Hg from the cells that reduced general stress responses to the Hg-treatment. Expression changes in S. medicae while in bacteroids showed that both rhizobia strain and host-plant tolerance affected the number of DEGs. Aside from Mer operon genes, nif genes which are involved in nitrogenase activity in S. medicae showed significant up-regulation in the most Hg-tolerant strain while inside the most Hg-accumulating host-plant. Transfer of a plasmid containing the Mer operon from the most tolerant strain to low-tolerant strains resulted in an immediate increase in Hg tolerance, indicating that the Mer operon is able to confer hyper tolerance to Hg. Conclusions Mer operons have not been previously reported in nitrogen-fixing rhizobia. This study demonstrates a pivotal role of the Mer operon in effective mercury detoxification and hypertolerance in nitrogen-fixing rhizobia. This finding has major implications not only for soil bioremediation, but also host plants growing in mercury contaminated soils.

59 BASIC BIOLOGICAL SCIENCES↗
DOE OSTI2020

Novel Remediation of Mercury-Contaminated Sediments Using Manganese Oxide and Activated Carbon Amendments - 20394

Mercury contamination in sediments poses a challenging remediation problem because of its ability to biogeochemically cycle and biomagnify in the food chain as methylmercury from low resident sediment and porewater concentrations. One mitigation approach is to lower the overall rate of net methylmercury production by creating conditions unfavorable for sulfate and iron reduction or methanogenesis, the primary pathways for methylation of inorganic mercury. Manganese oxides and other redox-active amendments are a promising and novel in situ amendment technology aimed at reducing net methylation of mercury though control of redox conditions in mercury-contaminated sediment-water systems. This paper reviews the thermodynamic and kinetic framework for this remediation technology, presents experimental and spectroscopic data illustrating the approach using solid manganese oxides, and discusses potential advantages, disadvantages, and applications. (authors)

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

How does Mercury Methylation Respond to Intensive Forest Management and the Creation of Anoxia in Floodplain Soils

This research endeavor, entitled “How does Mercury Methylation Respond to Intensive Forest Management and the Creation of Anoxia in Floodplain Soils?” represents a collaborative effort undertaken by the University of North Carolina at Greensboro, led by Principal Investigator Dr. James S. Coleman, the United States Forest Service Santee Experimental Forest (SEF) Station Director Dr. Carl C. Trettin as Co-Principal Investigator, and The Chinese University of Hong Kong Dr. Martin Tsz-Ki Tsui and Dr. Alex T. Chow serving as Co-Principal Investigators. The overarching objective of this proposed project was to capture and elucidate the immediate and short-term effects of forest disturbances, namely clear-cutting and thinning, on the biogeochemical cycling of mercury (Hg) within the SEF in Huger, South Carolina. To accomplish this objective, a two-year exploratory study was proposed to conduct soil sampling and measurements of Hg and toxic methylmercury (MeHg), and soil physiochemical data within the experimental watershed (WS77) at SEF, following the clear-cutting process initiated for the preparation of the native longleaf pine restoration project by the USFS. Based on our mercury and hydrological data assessment, we concluded that the implementation of forest management practices, particularly mechanical thinning and clear-cutting, appears to enhance the potential for Hg methylation. Furthermore, these forest management practices may disrupt and alter the storage, mobility, and transformations of atmospherically deposited Hg in these lowland forests. We advocate for further research to comprehensively evaluate the impact of forest management on Hg cycling within forest ecosystems.

54 ENVIRONMENTAL SCIENCES↗