Science.gov

Sample records for bromine isotopes

  1. Bromine and carbon isotope effects during photolysis of brominated phenols.

    PubMed

    Zakon, Yevgeni; Halicz, Ludwik; Gelman, Faina

    2013-12-17

    In the present study, carbon and bromine isotope effects during UV-photodegradation of bromophenols in aqueous and ethanolic solutions were determined. An anomalous relatively high inverse bromine isotope fractionation (εreactive position up to +5.1‰) along with normal carbon isotope effect (εreactive position of -12.6‰ to -23.4‰) observed in our study may be attributed to coexistence of both mass-dependent and mass-independent isotope fractionation of C-Br bond cleavage. Isotope effects of a similar scale were observed for all the studied reactions in ethanol, and for 4-bromophenol in aqueous solution. This may point out related radical mechanism for these processes. The lack of any carbon and bromine isotope effects during photodegradation of 2-bromophenol in aqueous solution possibly indicates that C-Br bond cleavage is not a rate-limiting step in the reaction. The bromine isotope fractionation, without any detectable carbon isotope effect, that was observed for 3-bromophenol photolysis in aqueous solution probably originates from mass-independent fractionation.

  2. Kinetic bromine isotope effect: example from the microbial debromination of brominated phenols.

    PubMed

    Bernstein, Anat; Ronen, Zeev; Levin, Elena; Halicz, Ludwik; Gelman, Faina

    2013-03-01

    The increasing use of kinetic isotope effects for environmental studies has motivated the development of new compound-specific isotope analysis techniques for emerging pollutants. Recently, high-precision bromine isotope analysis in individual brominated organic compounds was proposed, by the coupling of gas chromatography to a multi-collector inductively coupled plasma mass spectrometer using strontium as an external spike for instrumental bias correction. The present study, for the first time, demonstrates an application of this technique for determining bromine kinetic isotope effects during biological reaction, focusing on the reductive debromination of brominated phenols under anaerobic conditions. Results show bromine isotope enrichment factors (ε) of -0.76 ± 0.08, -0.46 ± 0.19, and -0.20 ± 0.06 ‰ for the debromination of 4-bromophenol, 2,4-dibromophenol, and 2,4,6-tribromophenol, respectively. These values are rather low, yet still high enough to be obtained with satisfying certainty. This further implies that the analytical method may be also appropriate for future environmental applications.

  3. Bromine isotope analysis - a tool for investigating biogeochemical cycle of bromine-containing organic and inorganic compounds in the environment

    NASA Astrophysics Data System (ADS)

    Gelman, F.; Bernstein, A.; Levin, E.; Ronen, Z.; Halicz, L.

    2012-04-01

    Bromine naturally occurs mainly in the form of bromide and is usually considered as a conservative tracer in the groundwater system. However, nowadays many synthetically produced organobromine compounds are introduced into the environment by humans. Due to a possible toxic effect of these compounds, investigation of their fate in the nature is of the utmost importance. In this sense, examination of isotopic composition of inorganic and organic bromine may serve as a powerful tool for understanding Br geochemical cycle. Due to a relatively small mass difference between the isotopes 81Br and 79Br, bromine isotope fractionation originating from biotic and abiotic processes is expected to be in the range of several permille. Therefore, a highly precise technique for the bromine isotope ratio analysis is required. This work presents a new methodology for the precise determination of bromine isotope ratio in inorganic bromides and individual organic compounds by MC-ICPMS. Attained external precision (2σ) up to 0.1‰ allowed employment of the developed technique for determination of the bromine isotope composition in organic and inorganic bromides and Br KIE in biogeochemical processes.

  4. Bromine

    USGS Publications Warehouse

    Ober, Joyce A.

    2011-01-01

    All U.S. production of bromine in 2010 came from underground brines in Arkansas. It was the leading mineral commodity produced in the state in terms of value. Albemarle Corp. and Chemtura Corp. recovered bromine.

  5. Bromine

    USGS Publications Warehouse

    Ober, J.A.

    2013-01-01

    The element bromine is found principally as a dissolved species in seawater, evaporitic (salt) lakes and underground brines associated with petroleum deposits. Seawater contains about 65 parts per million of bromine or an estimated 907 Gt (100 trillion st). In the Middle East, the highly saline waters of the Dead Sea are estimated to contain 907 Mt (1 billion st) of bromine. Bromine also may be recovered from seawater as a coproduct during evaporation to produce salt.

  6. Bromine

    USGS Publications Warehouse

    Ober, Joyce A.

    2012-01-01

    The element bromine is found principally as a dissolved species in seawater, evaporitic (salt) lakes and underground brines associated with petroleum deposits. Seawater contains about 65 parts per million of bromine or an estimated 100 Tt (110 trillion st). In the Middle East, the highly saline waters of the Dead Sea are estimated to contain 1 Gt (1.1billion st) of bromine. Bromine is also recovered from seawater as a coproduct during evaporation to produce salt.

  7. High precision determination of bromine isotope ratio by GC-MC-ICPMS

    NASA Astrophysics Data System (ADS)

    Gelman, Faina; Halicz, Ludwik

    2010-01-01

    This work presents a new methodology for the precise determination of bromine isotope ratio in individual organic compounds based on the simultaneous introduction of brominated organic compounds and strontium as an external spike into MC-ICPMS. Using the proposed methodology, an external precision (2[sigma]) up to 0.1[per mille sign] has been attained. The new approach for the bromine isotope ratio analysis could be applied for the investigating the fate of the organobromine compounds in the environment.

  8. Bromine

    USGS Publications Warehouse

    Apodaca, Lori E.

    2010-01-01

    The entire U.S. production of bromine in 2009 came from underground brines in Arkansas, where it was the leading mineral commodity produced in terms of value. Two companies, Albermarle Corp. and Chemtura Corp., were responsible for bromine recovery. Worldwide, the United States is still the leading producer. However, U.S. dominance has decreased, as countries like China, Israel, Japan and Jordan have strengthened their positions as world producers of elemental bromine.

  9. Application of dual carbon-bromine isotope analysis for investigating abiotic transformations of tribromoneopentyl alcohol (TBNPA).

    PubMed

    Kozell, Anna; Yecheskel, Yinon; Balaban, Noa; Dror, Ishai; Halicz, Ludwik; Ronen, Zeev; Gelman, Faina

    2015-04-07

    Many of polybrominated organic compounds, used as flame retardant additives, belong to the group of persistent organic pollutants. Compound-specific isotope analysis is one of the potential analytical tools for investigating their fate in the environment. However, the isotope effects associated with transformations of brominated organic compounds are still poorly explored. In the present study, we investigated carbon and bromine isotope fractionation during degradation of tribromoneopentyl alcohol (TBNPA), one of the widely used flame retardant additives, in three different chemical processes: transformation in aqueous alkaline solution (pH 8); reductive dehalogenation by zero-valent iron nanoparticles (nZVI) in anoxic conditions; oxidative degradation by H2O2 in the presence of CuO nanoparticles (nCuO). Two-dimensional carbon-bromine isotope plots (δ(13)C/Δ(81)Br) for each reaction gave different process-dependent isotope slopes (Λ(C/Br)): 25.2 ± 2.5 for alkaline hydrolysis (pH 8); 3.8 ± 0.5 for debromination in the presence of nZVI in anoxic conditions; ∞ in the case of catalytic oxidation by H2O2 with nCuO. The obtained isotope effects for both elements were generally in agreement with the values expected for the suggested reaction mechanisms. The results of the present study support further applications of dual carbon-bromine isotope analysis as a tool for identification of reaction pathway during transformations of brominated organic compounds in the environment.

  10. Dual Carbon-Bromine Stable Isotope Analysis Allows Distinguishing Transformation Pathways of Ethylene Dibromide.

    PubMed

    Kuntze, Kevin; Kozell, Anna; Richnow, Hans H; Halicz, Ludwik; Nijenhuis, Ivonne; Gelman, Faina

    2016-09-20

    The present study investigated dual carbon-bromine isotope fractionation of the common groundwater contaminant ethylene dibromide (EDB) during chemical and biological transformations, including aerobic and anaerobic biodegradation, alkaline hydrolysis, Fenton-like degradation, debromination by Zn(0) and reduced corrinoids. Significantly different correlation of carbon and bromine isotope fractionation (ΛC/Br) was observed not only for the processes following different transformation pathways, but also for abiotic and biotic processes with, the presumed, same formal chemical degradation mechanism. The studied processes resulted in a wide range of ΛC/Br values: ΛC/Br = 30.1 was observed for hydrolysis of EDB in alkaline solution; ΛC/Br between 4.2 and 5.3 were determined for dibromoelimination pathway with reduced corrinoids and Zn(0) particles; EDB biodegradation by Ancylobacter aquaticus and Sulfurospirillum multivorans resulted in ΛC/Br = 10.7 and 2.4, respectively; Fenton-like degradation resulted in carbon isotope fractionation only, leading to ΛC/Br ∞. Calculated carbon apparent kinetic isotope effects ((13)C-AKIE) fell with 1.005 to 1.035 within expected ranges according to the theoretical KIE, however, biotic transformations resulted in weaker carbon isotope effects than respective abiotic transformations. Relatively large bromine isotope effects with (81)Br-AKIE of 1.0012-1.002 and 1.0021-1.004 were observed for nucleophilic substitution and dibromoelimination, respectively, and reveal so far underestimated strong bromine isotope effects.

  11. Stable bromine isotopic composition of methyl bromide released from plant matter

    NASA Astrophysics Data System (ADS)

    Horst, Axel; Holmstrand, Henry; Andersson, Per; Thornton, Brett F.; Wishkerman, Asher; Keppler, Frank; Gustafsson, Örjan

    2014-01-01

    Methyl bromide (CH3Br) emitted from plants constitutes a natural source of bromine to the atmosphere, and is a component in the currently unbalanced global CH3Br budget. In the stratosphere, CH3Br contributes to ozone loss processes. Studies of stable isotope composition may reduce uncertainties in the atmospheric CH3Br budget, but require well-constrained isotope fingerprints of the source end members. Here we report the first measurements of stable bromine isotopes (δ81Br) in CH3Br from abiotic plant emissions. Incubations of both KBr-fortified pectin, a ubiquitous cell-stabilizing macromolecule, and of a natural halophyte (Salicornia fruticosa), yielded an enrichment factor (ε) of -2.00 ± 0.23‰ (1σ, n = 8) for pectin and -1.82 ± 0.02‰ (1σ, n = 4) for Salicornia (the relative amount of the heavier 81Br was decreased in CH3Br compared to the substrate salt). For short incubations, and up to 10% consumption of the salt substrate, this isotope effect was similar for temperatures from 30 up to 300 °C. For longer incubations of up to 90 h at 180 °C the δ81Br values increased from -2‰ to 0‰ for pectin and to -1‰ for Salicornia. These δ81Br source signatures of CH3Br formation from plant matter combine with similar data for carbon isotopes to facilitate multidimensional isotope diagnostics of the CH3Br budget.

  12. Bromine isotopic signature facilitates de novo sequencing of peptides in free-radical-initiated peptide sequencing (FRIPS) mass spectrometry.

    PubMed

    Nam, Jungjoo; Kwon, Hyuksu; Jang, Inae; Jeon, Aeran; Moon, Jingyu; Lee, Sun Young; Kang, Dukjin; Han, Sang Yun; Moon, Bongjin; Oh, Han Bin

    2015-02-01

    We recently showed that free-radical-initiated peptide sequencing mass spectrometry (FRIPS MS) assisted by the remarkable thermochemical stability of (2,2,6,6-tetramethyl-piperidin-1-yl)oxyl (TEMPO) is another attractive radical-driven peptide fragmentation MS tool. Facile homolytic cleavage of the bond between the benzylic carbon and the oxygen of the TEMPO moiety in o-TEMPO-Bz-C(O)-peptide and the high reactivity of the benzylic radical species generated in •Bz-C(O)-peptide are key elements leading to extensive radical-driven peptide backbone fragmentation. In the present study, we demonstrate that the incorporation of bromine into the benzene ring, i.e. o-TEMPO-Bz(Br)-C(O)-peptide, allows unambiguous distinction of the N-terminal peptide fragments from the C-terminal fragments through the unique bromine doublet isotopic signature. Furthermore, bromine substitution does not alter the overall radical-driven peptide backbone dissociation pathways of o-TEMPO-Bz-C(O)-peptide. From a practical perspective, the presence of the bromine isotopic signature in the N-terminal peptide fragments in TEMPO-assisted FRIPS MS represents a useful and cost-effective opportunity for de novo peptide sequencing.

  13. Compound Specific Isotope Analysis (CSIA) for chlorine and bromine: a review of techniques and applications to elucidate environmental sources and processes.

    PubMed

    Cincinelli, Alessandra; Pieri, Francesca; Zhang, Yuan; Seed, Mike; Jones, Kevin C

    2012-10-01

    Chlorinated and brominated compounds belong to the class of organohalogen compounds that have received attention because of their widespread occurrence, use and applications. Understanding the sources and transformation processes of these contaminants in the environment enables assessment of their possible impact on humans and ecosystems. Recently new and innovative methods of Compound Specific Isotope Analysis have started to be applied to characterize the origin and fate of compounds, their breakdown products and degradation rates in different environmental compartments. Almost all studies have focussed on determination of isotopes of C and H, only recently new methodologies have been developed to measure isotopes of Cl and Br. This review firstly gives a brief description of chemistry properties and geochemical cycle of chlorine and bromine followed by a summary of their uses and applications. In the second section, an overview of CSIA techniques and new challenges and successful applications are also presented.

  14. Brominated dibenzofurans

    Integrated Risk Information System (IRIS)

    Brominated dibenzofurans ; no CASRN Human health assessment information on a chemical substance is included in the IRIS database only after a comprehensive review of toxicity data , as outlined in the IRIS assessment development process . Sections I ( Health Hazard Assessments for Noncarcinogenic Ef

  15. Rubberized, Brominated Epoxies

    NASA Technical Reports Server (NTRS)

    Gilwee, W.; Kourtides, D.; Parker, J.; Nir, Z.

    1985-01-01

    Graphite/epoxy composite materials made with resins containing bromine and rubber additives. New composites tougher and more resistant to fire. Flame resistance increased by introducing bromine via commercial brominated flame-retartant polymeric additives.

  16. Bromine Safety

    SciTech Connect

    Meyers, B

    2001-04-09

    The production and handling in 1999 of about 200 million kilograms of bromine plus substantial derivatives thereof by Great Lakes Chemical Corp. and Albemarle Corporation in their southern Arkansas refineries gave OSHA Occupational Injury/Illness Rates (OIIR) in the range of 0.74 to 1.60 reportable OIIRs per 200,000 man hours. OIIRs for similar industries and a wide selection of other U.S. industries range from 1.6 to 23.9 in the most recent OSHA report. Occupational fatalities for the two companies in 1999 were zero compared to a range in the U.S.of zero for all computer manufacturing to 0.0445 percent for all of agriculture, forestry and fishing in the most recent OSHA report. These results show that bromine and its compounds can be considered as safe chemicals as a result of the bromine safety standards and practices at the two companies. The use of hydrobromic acid as an electrical energy storage medium in reversible PEM fuel cells is discussed. A study in 1979 of 20 megawatt halogen working fluid power plants by Oronzio de Nora Group found such energy to cost 2 to 2.5 times the prevailing base rate at that time. New conditions may reduce this relative cost. The energy storage aspect allows energy delivery at maximum demand times where the energy commands premium rates. The study also found marginal cost and performance advantages for hydrobromic acid over hydrochloric acid working fluid. Separate studies in the late 70s by General Electric also showed marginal performance advantages for hydrobromic acid.

  17. Bromination of Phenol

    ERIC Educational Resources Information Center

    Talbot, Christopher

    2013-01-01

    This "Science note" examines the bromination of phenol, a reaction that is commonly taught at A-level and IB (International Baccalaureate) as an example of electrophilic substitution. Phenol undergoes bromination with bromine or bromine water at room temperature. A white precipitate of 2,4,6-tribromophenol is rapidly formed. This…

  18. Isotope analysis of sulfur, bromine, and chlorine in individual anionic species by ion chromatography/multicollector-ICPMS.

    PubMed

    Zakon, Yevgeni; Halicz, Ludwik; Gelman, Faina

    2014-07-01

    We developed an analytical method for precise and accurate analysis of δ(34)S, δ(81)Br, and δ(37)Cl in individual anionic species by coupled ion chromatography (IC) and multicollector inductively coupled plasma mass spectrometry (MC-ICPMS). The method is based on the online separation and purification of ions by IC prior to their isotope analysis by MC-ICPMS. The developed technique significantly simplifies δ(34)S, δ(81)Br, and δ(37)Cl analysis in environmental samples. In cases when several anionic species of the same element are present in the sample, they might be analyzed in a single analytical run. Major isobaric interferences for the analyzed elements were reduced by using "dry" plasma conditions and applying sufficient mass resolution power. The sample-standard bracketing technique was used for instrumental drift correction. In the case of δ(34)S analysis, precisions up to 0.15‰ (1sd) have been achieved for analytes containing down to 5 nmol of S; for δ(81)Br, the attained precision was 0.1‰ (1sd) for analytes containing down to 0.6 nmol of Br. Precisions of 0.2‰ have been obtained for δ(37)Cl with analytes containing 0.7 μmol of Cl. Robustness of the developed analytical method, as well as high precisions and accuracies, has been demonstrated for the laboratory standard solutions and for environmental samples.

  19. 49 CFR 173.228 - Bromine pentafluoride or bromine trifluoride.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 49 Transportation 2 2014-10-01 2014-10-01 false Bromine pentafluoride or bromine trifluoride. 173... Class 1 and Class 7 § 173.228 Bromine pentafluoride or bromine trifluoride. (a) Bromine pentafluoride and bromine trifluoride are authorized in packagings as follows: (1) Specification 3A150,...

  20. 49 CFR 173.228 - Bromine pentafluoride or bromine trifluoride.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 49 Transportation 2 2010-10-01 2010-10-01 false Bromine pentafluoride or bromine trifluoride. 173... Class 1 and Class 7 § 173.228 Bromine pentafluoride or bromine trifluoride. (a) Bromine pentafluoride and bromine trifluoride are authorized in packagings as follows: (1) Specification 3A150,...

  1. 49 CFR 173.228 - Bromine pentafluoride or bromine trifluoride.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 49 Transportation 2 2011-10-01 2011-10-01 false Bromine pentafluoride or bromine trifluoride. 173... Class 1 and Class 7 § 173.228 Bromine pentafluoride or bromine trifluoride. (a) Bromine pentafluoride and bromine trifluoride are authorized in packagings as follows: (1) Specification 3A150,...

  2. 49 CFR 173.228 - Bromine pentafluoride or bromine trifluoride.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 49 Transportation 2 2013-10-01 2013-10-01 false Bromine pentafluoride or bromine trifluoride. 173... Class 1 and Class 7 § 173.228 Bromine pentafluoride or bromine trifluoride. (a) Bromine pentafluoride and bromine trifluoride are authorized in packagings as follows: (1) Specification 3A150,...

  3. 49 CFR 173.228 - Bromine pentafluoride or bromine trifluoride.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 49 Transportation 2 2012-10-01 2012-10-01 false Bromine pentafluoride or bromine trifluoride. 173... Class 1 and Class 7 § 173.228 Bromine pentafluoride or bromine trifluoride. (a) Bromine pentafluoride and bromine trifluoride are authorized in packagings as follows: (1) Specification 3A150,...

  4. Speciation analysis of bromine-containing drug metabolites in feces samples from a human in vivo study by means of HPLC/ICP-MS combined with on-line isotope dilution.

    PubMed

    Meermann, Björn; Bockx, Marc; Laenen, Aline; Van Looveren, Cis; Cuyckens, Filip; Vanhaecke, Frank

    2012-01-01

    The aim of this work was speciation analysis of metabolites in feces samples collected within a clinical study during which a bromine-containing anti-tuberculosis drug (TMC207) was administered to patients with multi-drug resistant tuberculosis infection. Owing to slow elimination of the drug, no (14)C label was used within this study. Quantification of the bromine species was accomplished using high performance liquid chromatography coupled to inductively coupled plasma-mass spectrometry (HPLC/ICP-MS) in combination with on-line isotope dilution (on-line ID), while structural elucidation of the species was performed using HPLC coupled to electrospray ionization-mass spectrometry. The ICP-MS-based method developed shows a good intra- and inter-day reproducibility (relative standard deviation = 3.5%, N = 9); the limit of detection (1.5 mg TMC207 L(-1)) is of the same order of magnitude as that for HPLC/radiodetection; the dynamic range of the method covers more than two orders of magnitude. Furthermore, the column recovery was demonstrated to be quantitative (recoveries between 90.6% and 99.5%). Based on the excellent figures of merit, the "cold" HPLC/ICP-MS approach could be deployed for the actual human in vivo metabolism study, such that exposure of the human volunteers to the (14)C radiolabel was avoided.

  5. Determination of Bromine Stable Isotope Ratios from Saline Solutions by "Wet Plasma" MC-ICPMS Including a Comparison between High- and Low-Resolution Modes, and Three Introduction Systems.

    PubMed

    Louvat, Pascale; Bonifacie, Magali; Giunta, Thomas; Michel, Agnès; Coleman, Max

    2016-04-05

    We describe a novel method for measuring stable bromine isotope compositions in saline solutions such as seawater, brines, and formation waters. Bromine is extracted from the samples by ion exchange chromatography on anion exchange resin AG 1-X4 with NH4NO3 and measured by MC-ICP-MS in wet plasma conditions. Sample introduction through a small spray chamber provided good sensitivity and stability of the Br signal compared to direct injection (d-DIHEN) and desolvation (APEX). NH4NO3 media allowed fast (<3 min) washing of the system. Despite Ar2H(+) spectral interference on (81)Br(+), for the first time low-resolution mode (with appropriate tuning of Ar2H(+)/(81)Br(+) sensitivity) gave higher precision (81)Br/(79)Br measurements than high-resolution (HR), due to the narrowness of the (81)Br(+) plateau in HR mode and to slight mass drifting with time. Additionally, 1 μg Br is the lower amount needed for a triplicate determination of δ(81)Br by MC-ICP-MS, with reproducibility often < ± 0.1‰ (2 SD). Four HBr solutions were prepared by evaporation/condensation in order to obtain in-house reference solutions with 3‰ variations in δ(81)Br and to assess the reproducibility and accuracy of the method. Long-term (>3 years) reproducibility between ± 0.11 and ± 0.27‰ (2 SD) was obtained for the four HBr solutions, the international standard reference material NIST SRM 977 (δ(81)BrSMOB = -0.65 ± 1.1‰, 1 SD), and seawaters (synthetic and natural). The accuracy of the MC-ICP-MS method was validated by comparing the δ(81)Br obtained for these solutions with dual-inlet IRMS measurements on CH3Br gas. Finally, the method was successfully applied to 22 natural samples.

  6. Recover bromine on site

    SciTech Connect

    Schubert, P.; Mahajan, S.; Beatty, R.D.; Rostrup-Nielsen, T.; Schubert, D.W.; Lu, Phat Tan

    1993-04-01

    Chemists have long recognized the importance of recovering bromine from waste streams, and attempts to do so catalytically date back more than 50 years. Although the early interest in bromine recovery was driven primarily by economics, increased environmental pressures are providing additional incentives to recycle this element. As the acceptability of discharging wastes into the environment decreases, the cost of doing so increases, creating a need for alternative handling. The authors interest in waste bromine recovery was driven by both economic and environmental factors. In their evaluation of a research program that included a bromination step as part of a synthesis process, Catalytica researchers found that the process would be feasible commercially only if the waste HBr produced were recycled on site to bromine. A nonbromine route was eventually adopted for this particular research program, but the need for an economical and environmentally sound process for recycling HBr to bromine was recognized. The development of this process became a project in its own right. This process eliminates the need to form and ship aqueous sodium bromide offsite. It converts the waste HBr directly to bromine by catalytic oxidation.

  7. Measurements of stratospheric bromine

    NASA Technical Reports Server (NTRS)

    Sedlacek, W. A.; Lazrus, A. L.; Gandrud, B. W.

    1984-01-01

    From 1974 to 1977, molecules containing acidic bromine were sampled in the stratosphere by using tetrabutyl ammonium hydroxide impregnated filters. Sampling was accomplished by WB-57F aircraft and high-altitude balloons, spanning latitudes from the equator to 75 deg N and altitudes up to 36.6 km. Analytical results are reported for 4 years of measurements and for laboratory simulations that determined the filter collection efficiencies for a number of brominated species. Mass mixing ratios for the collected bromine species in air average about 27 pptm in the stratosphere. Seasonal variability seems to be small.

  8. Solid bromine complexers

    DOEpatents

    Grimes, Patrick G.

    1987-01-20

    The cell of the invention comprises a housing, a zinc or cadmium anode, a chemically non-reactive counterelectrode and cathodic halogen. The cathodic halogen is selected from chlorine and bromine, and preferably is bromine. The cell also is provided with an aqueous metal halide containing electrolyte in which the metal ions are of the same metal as the metal of the anode and halide anions are of the same halogen as the cathodic halogen material. Importantly, in the present invention, anion exchange resins provide a convenient means for storing the halogen generated during charging of the cell and providing a source of halogen to be used in the discharge of the cell.

  9. Lithium/bromine cell systems

    SciTech Connect

    Howard, W.G.; Skarstad, P.M.; Hayes, T.G.; Owens, B.B.

    1980-01-01

    Bromine is attractive as a cathode material because cells with a high energy density and high cell voltage are theoretically possible. The addition of small amounts of certain salts or organic compounds results in bromine solutions of sufficient conductivity for cathode applications. However, given these highly conductive bromine cathodes, lithium/bromine cells are limited in rate and practical available capacity by the high resistivity of the discharge product. The rate of resistance increase for the best bromine cells in this study is more than one order of magnitude greater than that observed for corresponding lithium/iodine cells. Lithium/bromine cells can function at pacemaker rates and they may be superior to cells used in early pacemakers. However, the authors have not found the lithium/bromine cells described to be superior to existing lithium/iodine cells available for cardiac pacemakers. 17 refs.

  10. Brominated Flame Retardants

    EPA Science Inventory

    Brominated flame retardants (BFRs) belong to a large class of compounds known as organohalogens. BFRs are currently the largest marketed flame retardant group due to their high performance efficiency and low cost. In the commercial market, more than 75 different BFRs are recogniz...

  11. Microbial degradation of the brominated flame retardant TBNPA by groundwater bacteria: laboratory and field study.

    PubMed

    Balaban, Noa; Bernstein, Anat; Gelman, Faina; Ronen, Zeev

    2016-08-01

    In the present study, the biodegradation of the brominated flame retardant tribromoneopentylalcohol (TBNPA) by a groundwater enrichment culture was investigated using a dual carbon ((13)C/(12)C)- bromine ((81)Br/(79)Br) stable isotope analysis. An indigenous aerobic bacterial consortium was enriched from the polluted groundwater underlying an industrial site in the northern Negev Desert, Israel, where TBNPA is an abundant pollutant. Aerobic biodegradation was shown to be rapid, with complete debromination within a few days, whereas anaerobic biodegradation was not observed. Biodegradation under aerobic conditions was accompanied by a significant carbon isotope effect with an isotopic enrichment factor of ɛCbulk = -8.8‰ ± 1.5‰, without any detectable bromine isotope fractionation. It was found that molecular oxygen is necessary for biodegradation to occur, suggesting an initial oxidative step. Based on these results, it was proposed that H abstraction from the C-H bond is the first step of TBNPA biodegradation under aerobic conditions, and that the C-H bond cleavage results in the formation of unstable intermediates, which are rapidly debrominated. A preliminary isotopic analysis of TBNPA in the groundwater underlying the industrial area revealed that there are no changes in the carbon and bromine isotope ratio values downstream of the contamination source. Considering that anoxic conditions prevail in the groundwater of the contaminated site, the lack of isotope shifts in TBNPA indicates the lack of TBNPA biodegradation in the groundwater, in accordance with our findings.

  12. INTRODUCTION TO BROMINATED FLAME RETARDANTS

    EPA Science Inventory

    Brominated flame retardants (BFRs) are a large and diverse class of major industrial products used to provide fire safety. Tetrabromobisphenol A (TBBPA), Hexabromocylocodecane (HBCD), and Polybrominated Diphenyl Ethers (PBDEs) are the major commercial compounds. TBBPA is a react...

  13. Zinc-bromine battery development

    NASA Astrophysics Data System (ADS)

    Richards, Lew; Vanschalwijk, Walter; Albert, George; Tarjanyi, Mike; Leo, Anthony; Lott, Stephen

    1990-05-01

    This report describes development activities on the zinc-bromine battery system conducted by Energy Research Corporation (ERC). The project was a cost-shared program supported by the U.S. Department of Energy and managed through Sandia. The project began in September 1985 and ran through January 1990. The zinc-bromine battery has been identified as a promising alternative to conventional energy storage options for many applications. The low cost of the battery reactants and the potential for long life make the system an attractive candidate for bulk energy storage applications, such as utility load leveling. The battery stores energy by the electrolysis of an aqueous zinc bromide salt to zinc metal and dissolved bromine. Zinc is plated as a layer on the electrode surface while bromine is dissolved in the electrolyte and carried out of the stack. The bromine is then extracted from the electrolyte with an organic complexing agent in the positive electrolyte storage tank. On discharge the zinc and bromine are consumed, regenerating the zinc bromide salt.

  14. 49 CFR 173.249 - Bromine.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 49 Transportation 2 2013-10-01 2013-10-01 false Bromine. 173.249 Section 173.249 Transportation... PACKAGINGS Bulk Packaging for Hazardous Materials Other Than Class 1 and Class 7 § 173.249 Bromine. When... bromine service built prior to August 31, 1991, may continue in service under the requirements...

  15. 49 CFR 173.249 - Bromine.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 49 Transportation 2 2014-10-01 2014-10-01 false Bromine. 173.249 Section 173.249 Transportation... PACKAGINGS Bulk Packaging for Hazardous Materials Other Than Class 1 and Class 7 § 173.249 Bromine. When... bromine service built prior to August 31, 1991, may continue in service under the requirements...

  16. 49 CFR 173.249 - Bromine.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 49 Transportation 2 2011-10-01 2011-10-01 false Bromine. 173.249 Section 173.249 Transportation... PACKAGINGS Bulk Packaging for Hazardous Materials Other Than Class 1 and Class 7 § 173.249 Bromine. When... bromine service built prior to August 31, 1991, may continue in service under the requirements...

  17. 49 CFR 173.249 - Bromine.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 49 Transportation 2 2012-10-01 2012-10-01 false Bromine. 173.249 Section 173.249 Transportation... PACKAGINGS Bulk Packaging for Hazardous Materials Other Than Class 1 and Class 7 § 173.249 Bromine. When... bromine service built prior to August 31, 1991, may continue in service under the requirements...

  18. Mineral Resource of the Month: Bromine

    USGS Publications Warehouse

    Schnebele, Emily

    2015-01-01

    Bromine, along with mercury, is one of only two elements that are liquid at room temperature. Bromine is a highly volatile and corrosive reddish-brown liquid that evaporates easily and converts to a metal at extreme pressures — above about 540,000 times atmospheric pressure. Bromine occurs in seawater, evaporitic (salt) lakes and underground brines associated with petroleum deposits. 

  19. Electronic properties of bromine-doped carbon nanotubes

    SciTech Connect

    Jhi, Seung-Hoon; Louie, Steven G.; Cohen, Marvin L.

    2002-07-15

    Intercalation of bromine molecules (Br2) into single-wall carbon nanotube (SWNT) ropes is studied using the ab initio pseudopotential density functional method. Electronic and vibrational properties of the SWNT and Br2 are studied for various bromine concentrations. A drastic change in the charge transfer, bromine stretching-mode, and bromine bond-length is observed when the bromine-bromine distance decreases. Calculated electronic structures show that, at high bromine concentrations, the bromine ppsigma level broadens due to the interbromine interaction. These states overlap with the electronic bands of the SWNT near the Fermi level which results in a substantial charge transfer from carbon to bromine.

  20. Stability of Bromine Intercalated Graphite Fibers

    NASA Technical Reports Server (NTRS)

    Gaier, J. R.

    1984-01-01

    Previous evidence suggested that bromine intercalation compounds of crystalline graphite spontaneously deintercalate when the bromine atmosphere is removed. However, results show that bromine intercalated P-100 graphite fibers are stable for long periods of time. They are stable under vacuum conditions, high humidity, and current densities up to 24,000 A/sq cm. They are thermally stable to 200 C, and at temperatures as high as 400 C still retain 80 percent of the conductivity gained by intercalation. At temperatures greater than 300 C, there is significant oxidative degradation of the fibers. The environmental stability shown by the bromine compound makes it a promising candidate for practical applications in aerospace technology.

  1. Bromination of olefins with HBr and DMSO.

    PubMed

    Karki, Megha; Magolan, Jakob

    2015-04-03

    A simple and inexpensive methodology is reported for the conversion of alkenes to 1,2-dibromo alkanes via oxidative bromination using HBr paired with dimethyl sulfoxide, which serves as the oxidant as well as cosolvent. The substrate scope includes 21 olefins brominated in good to excellent yields. Three of six styrene derivatives yielded bromohydrins under the reaction conditions.

  2. Mineral resource of the month: bromine

    USGS Publications Warehouse

    ,

    2009-01-01

    The article offers information on bromine, a natural element considered as a dissolved species in seawater, saltwater lakes and underground brines linked with petroleum deposits. Bromine belongs to the halogen group of elements and is characterized with brownish-red color and beach-like odor. It is commonly used in flame retardants, agriculture and drilling.

  3. Brominated carbon black: An EDXD study

    SciTech Connect

    Carbone, Marilena; Gontrani, Lorenzo

    2014-06-19

    An energy dispersive X-Ray study of pure and brominated carbon black was carried out. The analysis of the diffraction patterns reveals that the low bromine load (ca.1% mol) is trapped into the structure, without significantly modifying it. This allows the application of the difference methods, widely tested for electrolyte solutions, inorganic matrices containing metals and isomorphic substitutions.

  4. Penetration of polar brominated DBPs through the activated carbon columns during total organic bromine analysis.

    PubMed

    Li, Yao; Zhang, Xiangru; Krasner, Stuart W; Shang, Chii; Zhai, Hongyan; Liu, Jiaqi; Yang, Mengting

    2011-10-01

    Total organic bromine (TOBr) is a collective parameter representing all the brominated organic disinfection byproducts (DBPs) in water samples. TOBr can be measured using the adsorption-pyrolysis method according to Standard Method 5320B. This method involves that brominated organic DBPs are separated from inorganic halides and concentrated from aqueous solution by adsorption onto the activated carbon (AC). Previous studies have reported that some commonly known brominated DBPs can partially penetrate through the AC during this adsorption step. In this work, the penetration of polar brominated DBPs through AC and ozone-modified AC was explored with two simulated drinking water samples and one chlorinated wastewater effluent sample. Polar brominated DBPs were selectively detected with a novel precursor ion scan method using electrospray ionization-triple quadrupole mass spectrometry. The results show that 3.4% and 10.4% of polar brominated DBPs (in terms of total ion intensity) in the chlorinated Suwannee River fulvic acid and humic acid samples, respectively, penetrated through the AC, and 19.6% of polar brominated DBPs in the chlorinated secondary wastewater effluent sample penetrated through the AC. The ozone-modification of AC minimized the penetration of polar brominated DBPs during the TOBr analysis.

  5. Brominated Flame Retardants and Perfluorinated Chemicals

    EPA Science Inventory

    Brominated flame retardants (BFRs) and perfluorinated chemicals (PFCs) belong to a large class of chemicals known as organohalogens. It is believed that both BFRs and PFCs saved lives by reducing flammability of materials commonly used and bactericidal (biocidal) properties. Thes...

  6. Systematic vibration thermodynamic properties of bromine

    NASA Astrophysics Data System (ADS)

    Liu, G. Y.; Sun, W. G.; Liao, B. T.

    2015-11-01

    Based on the analysis of the maturity and finiteness of vibrational levels of bromine molecule in ground state and evaluating the effect on statistical computation, according to the elementary principles of quantum statistical theorem, using the full set of bromine molecular vibrational levels determined with algebra method, the statistical contribution for bromine systematical macroscopic thermodynamic properties is discussed. Thermodynamic state functions Helmholtz free energy, entropy and observable vibration heat capacity are calculated. The results show that the determination of full set of vibrational levels and maximum vibrational quantum number is the key in the correct statistical analysis of bromine systematical thermodynamic property. Algebra method results are clearly different from data of simple harmonic oscillator and the related algebra method results are no longer analytical but numerical and are superior to simple harmonic oscillator results. Compared with simple harmonic oscillator's heat capacities, the algebra method's heat capacities are more consistent with the experimental data in the given temperature range of 600-2100 K.

  7. PCBs, PBBs and Brominated Flame Retardants

    EPA Science Inventory

    This chapter introduces selected organohalogen chemicals such as polychlorinated biphenyls (PCB5), polychiorinated biphenyls (PBBs), and brominated flame retardants (BFRs) with emphasis on the background, physicochemical properties, environmental levels, health effects and possib...

  8. 75 FR 16104 - Bromine Registration Review Final Decision; Notice of Availability

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-03-31

    ... AGENCY Bromine Registration Review Final Decision; Notice of Availability AGENCY: Environmental... registration review decision for the pesticide Bromine, case 4015. Registration review is EPA's periodic review... registration review decision for bromine, case 4015. Bromine is a bromide releasing antimicrobial...

  9. Bromine accumulation in acidic black colluvial soils

    NASA Astrophysics Data System (ADS)

    Cortizas, Antonio Martínez; Vázquez, Cruz Ferro; Kaal, Joeri; Biester, Harald; Casais, Manuela Costa; Rodríguez, Teresa Taboada; Lado, Luis Rodríguez

    2016-02-01

    Recent investigations showed that bromine is incorporated to soil organic matter (SOM), its content increasing with humification. But few research was done on its long-term accumulation and the role played by pedogenetic processes, as those involved in organic matter stabilization. We investigated bromine content and distribution in four deep, acidic, organic-rich, Holocene soils from an oceanic area of Western Europe. Bromine concentrations (93-778 μg g-1) in the silt + clay (<50 μm) fraction were on average 3-times higher than those (17-250 μg g-1) in the fine earth (<2 mm), the former containing almost all bromine (90 ± 5%). Inventories were between 148 and 314 g m-2, indicating a rather large variability in a small area, and total estimated retention was low (6-16%). The degree of SOM bromination, expressed as the Br/C molar ratio, varied between 0.03 and 1.20 mmol Br/mol C. The ratio was highly correlated (n = 23, r2 0.88, p < 0.01) with the age of the SOM for the last ∼12 ka. Partial least squares modeling indicates that bromine concentration depends on the amount of organic matter stabilized as aluminium-OM associations, and to a lesser extent on soil acidity (pH) and iron-OM associations. Thus, at scales of thousands of years, bromine accumulation in acidic soils is linked to the pool of metal-clay-stabilized organic matter.

  10. Abiotic Bromination of Soil Organic Matter.

    PubMed

    Leri, Alessandra C; Ravel, Bruce

    2015-11-17

    Biogeochemical transformations of plant-derived soil organic matter (SOM) involve complex abiotic and microbially mediated reactions. One such reaction is halogenation, which occurs naturally in the soil environment and has been associated with enzymatic activity of decomposer organisms. Building on a recent finding that naturally produced organobromine is ubiquitous in SOM, we hypothesized that inorganic bromide could be subject to abiotic oxidations resulting in bromination of SOM. Through lab-based degradation treatments of plant material and soil humus, we have shown that abiotic bromination of particulate organic matter occurs in the presence of a range of inorganic oxidants, including hydrogen peroxide and assorted forms of ferric iron, producing both aliphatic and aromatic forms of organobromine. Bromination of oak and pine litter is limited primarily by bromide concentration. Fresh plant material is more susceptible to bromination than decayed litter and soil humus, due to a labile pool of mainly aliphatic compounds that break down during early stages of SOM formation. As the first evidence of abiotic bromination of particulate SOM, this study identifies a mechanistic source of the natural organobromine in humic substances and the soil organic horizon. Formation of organobromine through oxidative treatments of plant material also provides insights into the relative stability of aromatic and aliphatic components of SOM.

  11. The milling of pristine and brominated P-100 graphite fibers

    NASA Technical Reports Server (NTRS)

    Dillehay, M. E.; Gaier, J. R.

    1986-01-01

    Techniques were developed for the ball milling of pristine and brominated P-100 graphite fibers. Because of the lubrication properties of graphite, large ball loads (50 percent by volume) were required. Use of 2-propanol as a milling medium enhanced the efficiency of the process. Milled brominated P-100 fibers had resistivities which were indistinguishable from milled pristine P-100 fibers. Apparent loss of bromine from the brominated fibers suggests that bromine would not be the intercalate of choice in applications where milled fibers of this type are required. Other intercalates which do not degas may be more appropriate for a milled fiber application. These same results, however, do provide evidence that bromine molecules leave the fiber surface when removed from overpressure of bromine. While exploring possible solvent media for milling purposes, it was found that brominated fibers are stable in a wide variety of organic solvents.

  12. 40 CFR 721.2925 - Brominated aromatic ester.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 40 Protection of Environment 30 2010-07-01 2010-07-01 false Brominated aromatic ester. 721.2925... Substances § 721.2925 Brominated aromatic ester. (a) Chemical substance and significant new uses subject to reporting. (1) The chemical substance identified generically as a brominated aromatic ester (PMN...

  13. 40 CFR 721.3085 - Brominated phthalate ester.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 40 Protection of Environment 30 2010-07-01 2010-07-01 false Brominated phthalate ester. 721.3085... Substances § 721.3085 Brominated phthalate ester. (a) Chemical substance and significant new uses subject to reporting. (1) The chemical substance identified generically as brominated phthalate ester (PMN P-90-581)...

  14. 40 CFR 721.3085 - Brominated phthalate ester.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 40 Protection of Environment 31 2011-07-01 2011-07-01 false Brominated phthalate ester. 721.3085... Substances § 721.3085 Brominated phthalate ester. (a) Chemical substance and significant new uses subject to reporting. (1) The chemical substance identified generically as brominated phthalate ester (PMN P-90-581)...

  15. 40 CFR 721.2925 - Brominated aromatic ester.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 40 Protection of Environment 31 2011-07-01 2011-07-01 false Brominated aromatic ester. 721.2925... Substances § 721.2925 Brominated aromatic ester. (a) Chemical substance and significant new uses subject to reporting. (1) The chemical substance identified generically as a brominated aromatic ester (PMN...

  16. 40 CFR 721.3085 - Brominated phthalate ester.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 40 Protection of Environment 32 2013-07-01 2013-07-01 false Brominated phthalate ester. 721.3085... Substances § 721.3085 Brominated phthalate ester. (a) Chemical substance and significant new uses subject to reporting. (1) The chemical substance identified generically as brominated phthalate ester (PMN P-90-581)...

  17. 40 CFR 721.3085 - Brominated phthalate ester.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 40 Protection of Environment 32 2012-07-01 2012-07-01 false Brominated phthalate ester. 721.3085... Substances § 721.3085 Brominated phthalate ester. (a) Chemical substance and significant new uses subject to reporting. (1) The chemical substance identified generically as brominated phthalate ester (PMN P-90-581)...

  18. 40 CFR 721.2925 - Brominated aromatic ester.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 40 Protection of Environment 31 2014-07-01 2014-07-01 false Brominated aromatic ester. 721.2925... Substances § 721.2925 Brominated aromatic ester. (a) Chemical substance and significant new uses subject to reporting. (1) The chemical substance identified generically as a brominated aromatic ester (PMN...

  19. 40 CFR 721.2925 - Brominated aromatic ester.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 40 Protection of Environment 32 2013-07-01 2013-07-01 false Brominated aromatic ester. 721.2925... Substances § 721.2925 Brominated aromatic ester. (a) Chemical substance and significant new uses subject to reporting. (1) The chemical substance identified generically as a brominated aromatic ester (PMN...

  20. 40 CFR 721.3085 - Brominated phthalate ester.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 40 Protection of Environment 31 2014-07-01 2014-07-01 false Brominated phthalate ester. 721.3085... Substances § 721.3085 Brominated phthalate ester. (a) Chemical substance and significant new uses subject to reporting. (1) The chemical substance identified generically as brominated phthalate ester (PMN P-90-581)...

  1. 40 CFR 721.2925 - Brominated aromatic ester.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 40 Protection of Environment 32 2012-07-01 2012-07-01 false Brominated aromatic ester. 721.2925... Substances § 721.2925 Brominated aromatic ester. (a) Chemical substance and significant new uses subject to reporting. (1) The chemical substance identified generically as a brominated aromatic ester (PMN...

  2. Numerical simulation of bromine crossover behavior in flow battery

    NASA Astrophysics Data System (ADS)

    Jia, Yaobin; Cheng, Shijian; Chu, Dandan; Li, Xin

    2017-03-01

    Br2 and HBr has its own series of advantages as the positive electrolyte solution, so some batteries select the Br2/Br- as the positive electrolyte solution, such as sodium polysulfide/bromine flow battery, zinc/bromine flow battery, vanadium/ bromine flow batteries and hydrogen/bromine flow batteries. But the crossover benavior of bromine occurs in these batteries too, resulting in cross-contamination, capacity loss and affecting battery's performance. In this work, we build numerical models to study the influence of bromine crossover phenomenon on the three forms of bromine crossover, the concentration of electrolyte on the cathode side and the flow rate of the negative side in the quinone bromine flow battery, to find the main models affecting the bromine crossover and the impact of bromine crossover on battery performance. It was found that the three ways of crossover through the membranes was mainly by diffusion. By reducing the concentration of positive electrolyte solution, the bromine crossover can be reduced and Coulomb Efficiency can be improved. Rising the flow rate of the electrolyte solution on the negative side and reducing the differential between positive side's pressure and negative side's pressure can also reduce the amount of bromine crossover to improve Coulomb efficiency in the battery.

  3. 21 CFR 180.30 - Brominated vegetable oil.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 3 2012-04-01 2012-04-01 false Brominated vegetable oil. 180.30 Section 180.30... Brominated vegetable oil. The food additive brominated vegetable oil may be safely used in accordance with... used on an interim basis as a stabilizer for flavoring oils used in fruit-flavored beverages, for...

  4. 21 CFR 180.30 - Brominated vegetable oil.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 3 2013-04-01 2013-04-01 false Brominated vegetable oil. 180.30 Section 180.30... Brominated vegetable oil. The food additive brominated vegetable oil may be safely used in accordance with... used on an interim basis as a stabilizer for flavoring oils used in fruit-flavored beverages, for...

  5. 21 CFR 180.30 - Brominated vegetable oil.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 3 2014-04-01 2014-04-01 false Brominated vegetable oil. 180.30 Section 180.30... Requirements for Certain Food Additives § 180.30 Brominated vegetable oil. The food additive brominated vegetable oil may be safely used in accordance with the following prescribed conditions: (a) The...

  6. 21 CFR 180.30 - Brominated vegetable oil.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 3 2010-04-01 2009-04-01 true Brominated vegetable oil. 180.30 Section 180.30... Brominated vegetable oil. The food additive brominated vegetable oil may be safely used in accordance with... used on an interim basis as a stabilizer for flavoring oils used in fruit-flavored beverages, for...

  7. 21 CFR 180.30 - Brominated vegetable oil.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 3 2011-04-01 2011-04-01 false Brominated vegetable oil. 180.30 Section 180.30... Brominated vegetable oil. The food additive brominated vegetable oil may be safely used in accordance with... used on an interim basis as a stabilizer for flavoring oils used in fruit-flavored beverages, for...

  8. 40 CFR 721.10124 - Brominated polyaromatic compound (generic).

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 40 Protection of Environment 31 2011-07-01 2011-07-01 false Brominated polyaromatic compound... Specific Chemical Substances § 721.10124 Brominated polyaromatic compound (generic). (a) Chemical substance... brominated polyaromatic compound (PMN P-06-617) is subject to reporting under this section for...

  9. 40 CFR 721.10124 - Brominated polyaromatic compound (generic).

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 40 Protection of Environment 31 2014-07-01 2014-07-01 false Brominated polyaromatic compound... Specific Chemical Substances § 721.10124 Brominated polyaromatic compound (generic). (a) Chemical substance... brominated polyaromatic compound (PMN P-06-617) is subject to reporting under this section for...

  10. 40 CFR 721.10124 - Brominated polyaromatic compound (generic).

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 40 Protection of Environment 32 2012-07-01 2012-07-01 false Brominated polyaromatic compound... Specific Chemical Substances § 721.10124 Brominated polyaromatic compound (generic). (a) Chemical substance... brominated polyaromatic compound (PMN P-06-617) is subject to reporting under this section for...

  11. 40 CFR 721.10124 - Brominated polyaromatic compound (generic).

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 40 Protection of Environment 32 2013-07-01 2013-07-01 false Brominated polyaromatic compound... Specific Chemical Substances § 721.10124 Brominated polyaromatic compound (generic). (a) Chemical substance... brominated polyaromatic compound (PMN P-06-617) is subject to reporting under this section for...

  12. Ninth Spectrum of Bromine: Br IX

    NASA Astrophysics Data System (ADS)

    Joshi, Y. N.; van Kleef, Th A. M.

    1981-03-01

    The spectrum of bromine was photographed on a 6.60 m and a 10.7 m grazing incidence spectrograph in the region 300-90 Å. The source used was a triggered spark. The ninth spectrum of bromine was analysed on the basis of 3d9-3d84p transitions between 125-104 Å. Parametric level fitting calculations support the analysis. 44 lines are classified in this spectrum. Some Br VIII lines appearing in this region have been accurately measured.

  13. Bromine and Chlorine Go Separate Ways

    NASA Technical Reports Server (NTRS)

    2004-01-01

    This graph shows the relative concentrations of bromine and chlorine at various locations on Earth and Mars. Typically, bromine and chlorine stick together in a fixed ratio, as in martian meteorites and Earth seawater. But sometimes the elements split apart and their relative quantities diverge. This separation is usually caused by evaporation processes, as in the Dead Sea on Earth. On Mars, at Meridiani Planum and Gusev Crater, this split has been observed to an even greater degree than seen on Earth. This puzzling result is currently being further explored by Mars Exploration Rover scientists. Data for the Mars locations were taken by the rover's alpha particle X-ray spectrometer.

  14. Optically pumped molecular bromine laser. Master's thesis

    SciTech Connect

    Morrison, J.W.

    1990-12-01

    An optically pumped molecular bromine laser was studied to investigate the quenching kinetics state of Br2. This included characterization of the pressure dependence of the laser output power. The approach was to excite molecular bromine in a sealed cell with a Nd:YAG pumped dye laser. Unresolved side fluorescence and amplified stimulated emission (ASE) spectra were recorded. ASE offered the advantage of a simpler optical system with no externally induced wavelength dependencies. Stimulated emission as a signal monitor offered greater resolution than side fluorescence spectra and facilitated spectroscopic assignment. (JS)

  15. Measurements of bromine containing organic compounds at the tropical tropopause

    NASA Astrophysics Data System (ADS)

    Schauffler, S. M.; Atlas, E. L.; Flocke, F.; Lueb, R. A.; Stroud, V.; Travnicek, W.

    The amount of bromine entering the stratosphere from organic source gases is a primary factor involved in determining the magnitude of bromine catalyzed loss of ozone. Thirty two whole air samples were collected at the tropical tropopause during the NASA STRAT Campaign in Feb., Aug., and Dec., 1996 and were analyzed for brominated organic compounds. Total organic bromine was 17.4±0.9 ppt with 55% from methyl bromide, 38% from the Halons, 6% from dibromomethane, and 0.8% from bromochloromethane and dichlorobromomethane. One flight showed the presence of 0.42 ppt of additional organic bromine from bromoform and dibromochloromethane.

  16. Preparation of ionic membranes for zinc/bromine storage batteries

    NASA Astrophysics Data System (ADS)

    Assink, R. A.; Arnold, C., Jr.

    Zinc/bromine flow batteries are being developed for vehicular and utility load leveling applications. During charge, an aqueous zinc bromide salt is electrolyzed to zinc metal and molecular bromine. During discharge, the zinc and bromine react to again form the zinc bromide salt. One serious disadvantage of the microporous separators presently used in the zinc/bromine battery is that modest amounts of bromine and negatively charged bromine moieties permeate through these materials and react with the zinc anode. This results in partial self-discharge of the battery and low coulombic efficiencies. Our approach to this problem is to impregnate the microporous separators with a soluble cationic polyelectrolyte. In laboratory screening tests a sulfonated polysulfone resin and fully fluorinated sulfonic acid polymer substantially reduced bromine permeation with only modest increases in the area resistance.

  17. Graphite fiber intercalation: Dynamics of the bromine intercalation process

    NASA Technical Reports Server (NTRS)

    Jaworske, D. A.; Zinolabedini, R.

    1985-01-01

    The resistance of pitch-based graphite fibers was monitored, in situ, during a series of bromine intercalation experiments. The threshold pressure for the bromine intercalation of pitch-based fibers was estimated to be 102 torr. When the bromine atmosphere was removed from the reaction chamber, the resistivity of the intercalated graphite fibers increased consistently. This increase was attributed to loss of bromine from the perimeter of the fiber. The loss was confirmed by mapping the bromine concentration across the diameter of single intercalated fibers with either energy dispersive spectroscopy or scanning Auger microscopy. A statistical study comparing fibers intercalated in bromine vapor with fibers intercalated in bromine liquid showed that similar products were obtained with both methods of intercalation.

  18. Bromination of selected pharmaceuticals in water matrices.

    PubMed

    Benitez, F Javier; Acero, Juan L; Real, Francisco J; Roldan, Gloria; Casas, Francisco

    2011-11-01

    The bromination of five selected pharmaceuticals (metoprolol, naproxen, amoxicillin, phenacetin, and hydrochlorothiazide) was studied with these compounds individually dissolved in ultra-pure water. The apparent rate constants for the bromination reaction were determined as a function of the pH, obtaining the sequence amoxicillin>naproxen>hydrochlorothiazide≈phenacetin≈metoprolol. A kinetic mechanism specifying the dissociation reactions and the species formed for each compound according to its pK(a) value and the pH allowed the intrinsic rate constants to be determined for each elementary reaction. There was fairly good agreement between the experimental and calculated values of the apparent rate constants, confirming the goodness of the proposed reaction mechanism. In a second stage, the bromination of the selected pharmaceuticals simultaneously dissolved in three water matrices (a groundwater, a surface water from a public reservoir, and a secondary effluent from a WWTP) was investigated. The pharmaceutical elimination trend agreed with the previously determined rate constants. The influence of the main operating conditions (pH, initial bromine dose, and characteristics of the water matrix) on the degradation of the pharmaceuticals was established. An elimination concentration profile for each pharmaceutical in the water matrices was proposed based on the use of the previously evaluated apparent rate constants, and the theoretical results agreed satisfactorily with experiment. Finally, chlorination experiments performed in the presence of bromide showed that low bromide concentrations slightly accelerate the oxidation of the selected pharmaceuticals during chlorine disinfection.

  19. HEALTH EFFECTS OF BROMINATED FLAME RETARDANTS (BFRS)

    EPA Science Inventory

    Abstract Brominated flame retardant use has increased dramatically in order to provide fire safety to consumers. However, there is growing concern about widespread environmental contamination and potential health risks from some of these products. The most used products...

  20. BROMINATED FLAME RETARDANTS: CAUSE FOR CONCERN?

    EPA Science Inventory

    Brominated flame retardants (BFRs) have routinely been added to consumer products for several decades in a successful effort to reduce fire-related injury and property damage. Recently, concern for this emerging class of chemicals has risen due to the occurrence of several class...

  1. BROMINATED FLAME RETARDANTS: WHY DO WE CARE?

    EPA Science Inventory

    Brominated flame retardants (BFRs) save lives and property by preventing the spread of fires or delaying the time of flashover, enhancing the time people have to escape. The worldwide production of BFRs exceeded 200,000 metric tons in 2003 placing them in the high production vol...

  2. A Substitute Foe "Bromine in Carbon Tetrachloride"

    ERIC Educational Resources Information Center

    Daley, Joshua M.; Landolt, Robert G.

    2005-01-01

    The addition of a dilute solution of bromine in carbon tetrachloride to a compound to test for carbon-carbon multiple bonds, which is one of the widely cited qualitative tests employed in organic chemistry is presented. Major advantages of this approach include the ease and rapidness of the procedure, the stability of the test solution over time,…

  3. HEALTH ASPECTS OF BROMINATED FLAME RETARDANTS (BFRS)

    EPA Science Inventory

    In order to reduce the societal costs of fires, flammability standards have been set for consumer products and equipment. Flame retardants containing bromine have constituted the largest share of this market due both to their efficiency and cost. While there are at least 75 dif...

  4. Structure and functionality of bromine doped graphite.

    PubMed

    Hamdan, Rashid; Kemper, A F; Cao, Chao; Cheng, H P

    2013-04-28

    First-principles calculations are used to study the enhanced in-plane conductivity observed experimentally in Br-doped graphite, and to study the effect of external stress on the structure and functionality of such systems. The model used in the numerical calculations is that of stage two doped graphite. The band structure near the Fermi surface of the doped systems with different bromine concentrations is compared to that of pure graphite, and the charge transfer between carbon and bromine atoms is analyzed to understand the conductivity change along different high symmetry directions. Our calculations show that, for large interlayer separation between doped graphite layers, bromine is stable in the molecular form (Br2). However, with increased compression (decreased layer-layer separation) Br2 molecules tend to dissociate. While in both forms, bromine is an electron acceptor. The charge exchange between the graphite layers and Br atoms is higher than that with Br2 molecules. Electron transfer to the Br atoms increases the number of hole carriers in the graphite sheets, resulting in an increase of conductivity.

  5. Structure and functionality of bromine doped graphite

    SciTech Connect

    Hamdan, Rashid; Kemper, A. F.; Cao Chao; Cheng, H. P.

    2013-04-28

    First-principles calculations are used to study the enhanced in-plane conductivity observed experimentally in Br-doped graphite, and to study the effect of external stress on the structure and functionality of such systems. The model used in the numerical calculations is that of stage two doped graphite. The band structure near the Fermi surface of the doped systems with different bromine concentrations is compared to that of pure graphite, and the charge transfer between carbon and bromine atoms is analyzed to understand the conductivity change along different high symmetry directions. Our calculations show that, for large interlayer separation between doped graphite layers, bromine is stable in the molecular form (Br{sub 2}). However, with increased compression (decreased layer-layer separation) Br{sub 2} molecules tend to dissociate. While in both forms, bromine is an electron acceptor. The charge exchange between the graphite layers and Br atoms is higher than that with Br{sub 2} molecules. Electron transfer to the Br atoms increases the number of hole carriers in the graphite sheets, resulting in an increase of conductivity.

  6. Brominated flame retardants as food contaminants

    Technology Transfer Automated Retrieval System (TEKTRAN)

    This book chapter reviews analytical methods for the three major brominated flame retardant (BFR) classes in use today, tetrabromobisphenol-A (TBBP-A), hexabromocyclododecanes (HBCDs), and polybrominated diphenyl ethers (PBDEs), a "legacy" BFR no longer in use, polybrominated biphenyls (PBBs), and a...

  7. Global Distribution of Organo-Bromine Gases.

    NASA Astrophysics Data System (ADS)

    Gunawardena, Rohith

    Both man-made and natural trace organo-bromine gases are present in the atmosphere in minute quantities --in the order of a few parts per trillion by volume. The man-made species CBrF_3 and CBrClF _2 are believed to be an important source of bromine to the stratosphere where they act as catalysts in the chlorofluorocarbon-ozone-depletion hypothesis. A high resolution capillary column EC-GC method with and O_2 doped detector was developed, System V, to measure these and related organo -bromine gases in the atmosphere. It was developed from a packed column EC-GC method, System I, that was used to measure CH_3I at sub pptv levels but could measure only one organo-bromine gas, CBrClF _2. The development work to improve upon System I involved testing and matching different types of columns, carrier gases, make-up gases to the detector and detector temperatures to obtain operating conditions with optimum resolution, very high sensitivity and sufficiently stable baseline to measure atmospheric organo-bromine gases. During this development work, nine organo-bromine gases were identified in clean background air. The precision of analysis of each system used was sufficient to determine the distributions and time course behavior of the species studied. During the course of this study, samples collected weekly at 11 remote stations around the world spanning latitudes from 82^circN down to 42^circS were analyzed for these organo-bromine gases. In addition, samples collected for 10 years at Cape Meares - Oregon, Cape Matatula - American Samoa, Cape Grim - Tasmania and at the South Pole during the austral summer months were analyzed for long term trends of CBrF_3 and CBrClF_2 . Significant altitudinal differences, interhemispheric gradients and seasonal cycles were observed for certain gases. Long-term trends were observed for CBrF _3 and CBrClF_2. CBrF _3 showed an exponential increase. From 1979 to 1987, its northern and southern hemispheric concentrations have increased at

  8. Search for Possible Stratospheric Bromine Reservoir Species: Theoretical Study of the Photostability of Mono-, Tri-, and Pentacoordinated Bromine Compounds

    NASA Technical Reports Server (NTRS)

    Lee, TImothy J.; Mejia, Cesar N.; Beran, J. O.; Head-Gordon, Martin

    2004-01-01

    Previous work has shown that pentacoordinated bromine compounds have their lowest excited electronic states shifted to the blue relative to monocoordinated bromine molecules, and that this shift may be large enough to render them photostable in the lower stratosphere. Our earlier work has also shown that certain pentacoordinated bromine compounds are thermodynamically stable relative to their mono- or tricoordinated isomers, suggesting that if a bromine stratospheric reservoir species exists, then it is most likely a pentacoordinated compound. In this study we have examined the singlet excited electronic states of several bromine compounds in order to assess their photostability excited states in mono-, tri-, and pentacoordinated bromine molecules. Due to the strong spin-orbit mixing in bromine, we have also examined the lowest triplet excited state.

  9. Brominated flame retardants: cause for concern?

    PubMed Central

    Birnbaum, Linda S; Staskal, Daniele F

    2004-01-01

    Brominated flame retardants (BFRs) have routinely been added to consumer products for several decades in a successful effort to reduce fire-related injury and property damage. Recently, concern for this emerging class of chemicals has risen because of the occurrence of several classes of BFRs in the environment and in human biota. The widespread production and use of BFRs; strong evidence of increasing contamination of the environment, wildlife, and people; and limited knowledge of potential effects heighten the importance of identifying emerging issues associated with the use of BFRs. In this article, we briefly review scientific issues associated with the use of tetrabromobisphenol A, hexabromocyclododecane, and three commercial mixtures of polybrominated diphenyl ethers and discuss data gaps. Overall, the toxicology database is very limited; the current literature is incomplete and often conflicting. Available data, however, raise concern over the use of certain classes of brominated flame retardants. PMID:14698924

  10. Membrane-less hydrogen bromine flow battery.

    PubMed

    Braff, William A; Bazant, Martin Z; Buie, Cullen R

    2013-01-01

    In order for the widely discussed benefits of flow batteries for electrochemical energy storage to be applied at large scale, the cost of the electrochemical stack must come down substantially. One promising avenue for reducing stack cost is to increase the system power density while maintaining efficiency, enabling smaller stacks. Here we report on a membrane-less hydrogen bromine laminar flow battery as a potential high-power density solution. The membrane-less design enables power densities of 0.795 W cm(-2) at room temperature and atmospheric pressure, with a round-trip voltage efficiency of 92% at 25% of peak power. Theoretical solutions are also presented to guide the design of future laminar flow batteries. The high-power density achieved by the hydrogen bromine laminar flow battery, along with the potential for rechargeable operation, will translate into smaller, inexpensive systems that could revolutionize the fields of large-scale energy storage and portable power systems.

  11. Marine bacterial degradation of brominated methanes

    USGS Publications Warehouse

    Goodwin, K.D.; Lidstrom, M.E.; Oremland, R.S.

    1997-01-01

    Brominated methanes are ozone-depleting compounds whose natural sources include marine algae such as kelp. Brominated methane degradation by bacteria was investigated to address whether bacterial processes might effect net emission of these compounds to the atmosphere. Bacteria in seawater collected from California kelp beds degraded CH2Br2 but not CHBr3. Specific inhibitors showed that methanotrophs and nitrifiers did not significantly contribute to CH2Br2 removal. A seawater enrichment culture oxidized 14CH2Br2 to 14CO2 as well as 14CH3Br to 14CO2. The rates of CH2Br2 degradation in laboratory experiments suggest that bacterial degradation of CH2Br2 in a kelp bed accounts for <1% of the CH2Br2 produced by the kelp. However, the half-life of CH2Br2 due to bacterial removal appears faster than hydrolysis and within an order of magnitude of volatilization to the atmosphere.Brominated methanes are ozone-depleting compounds whose natural sources include marine algae such as kelp. Brominated methane degradation by bacteria was investigated to address whether bacterial processes might effect net emission of these compounds to the atmosphere. Bacteria in seawater collected from California kelp beds degraded CH2Br2 but not CHBr3. Specific inhibitors showed that methanotrophs and nitrifiers did not significantly contribute to CH2Br2 removal. A seawater enrichment culture oxidized 14CH2Br2 to 14CO2 as well as 14CH3Br to 14CO2. The rates of CH2Br2 degradation in laboratory experiments suggest that bacterial degradation of CH2Br2 in a kelp bed accounts for <1% of the CH2Br2 produced by the kelp. However, the half-life of CH2Br2 due to bacterial removal appears faster than hydrolysis and within an order of magnitude of volatilization to the atmosphere.

  12. Catalytic bromine recovery from HBr waste

    SciTech Connect

    Schubert, P.F.; Beatty, R.D.; Mahajan, S.

    1993-12-31

    Waste HBr is formed during the bromination of many organic molecules, such as flame retardants, pharmaceuticals, and agricultural chemicals. For over 50 years attempts to recover the bromine from waste HBr by catalytic oxidation have been unsuccessful due to low catalyst activity and stability. The discovery of a new high-activity catalysts with excellent long-term stability and life capable of high HBr conversion below 300{degrees}C has made catalytic oxidation of waste HBr commercially feasible. The oxidation of anhydrous HBr using oxygen is highly exothermic, giving an adiabatic temperature rise of 2000{degrees}C. Use of 48 wt% HBr in the oxidation reduces the adiabatic temperature rise to only 300{degrees}C. A multitubular heat exchanger type of reactor can then be used to manage the heat. A 5,000 kg/yr pilot plant was built to verify the performance of the catalyst, the suitability of the reactor materials of construction, and the multibular reactor concept. The pilot unit has a single full-scale reactor tube 4 m long and 2.54 cm in diameter with a hot oil jacket for heat management. Excellent catalyst stability was observed during a 600 h catalyst-life test. HBr conversion of 99% was maintained throughout the run, and over 360 kg of bromine was produced. The temperature at a localized hot spot near the reactor inlet was only 15-20{degrees}C above the reactor inlet temperature, indicating efficient heat management.

  13. Silver-Catalyzed Decarboxylative Bromination of Aliphatic Carboxylic Acids.

    PubMed

    Tan, Xinqiang; Song, Tao; Wang, Zhentao; Chen, He; Cui, Lei; Li, Chaozhong

    2017-03-13

    The silver-catalyzed Hunsdiecker bromination of aliphatic carboxylic acids is described. With Ag(Phen)2OTf as the catalyst and dibromoisocyanuric acid as the brominating agent, various aliphatic carboxylic acids underwent decarboxylative bromination to provide the corresponding alkyl bromides under mild conditions. This method not only is efficient and general but also enjoys wide functional group compatibility. An oxidative radical mechanism involving Ag(II) intermediates is proposed.

  14. Oxidation of flame retardant tetrabromobisphenol a by aqueous permanganate: reaction kinetics, brominated products, and pathways.

    PubMed

    Pang, Su-Yan; Jiang, Jin; Gao, Yuan; Zhou, Yang; Huangfu, Xiaoliu; Liu, Yongze; Ma, Jun

    2014-01-01

    In this work, the most widely used brominated flame retardant tetrabromobisphenol A (TBrBPA) was shown to exhibit appreciable reactivity toward potassium permanganate [Mn(VII)] in water over a wide pH range of 5-10 with the maxima of second-order rate constants (kMn(VII) = 15-700 M(-1) s(-1)) at pH near its pKa values (7.5/8.5). A novel precursor ion scan (PIS) approach using negative electrospray ionization-triple quadrupole mass spectrometry (ESI-QqQMS) was adopted and further optimized for fast selective detection of brominated oxidation products of TBrBPA by Mn(VII). By setting PIS of m/z 79 and 81, two major products (i.e., 4-(2-hydroxyisopropyl)-2,6-dibromophenol and 4-isopropylene-2,6-dibromophenol) and five minor ones (including 2,6-dibromophenol, 2,6-dibromo-1,4-benzoquinone, and three dimers) were detected and suggested with chemical structures from their product ion spectra and bromine isotope patterns. Reaction pathways mainly involving the initial one-electron oxidation of TBrBPA and subsequent release and further reactions of 2,6-dibromo-4-isopropylphenol carbocation intermediate were proposed. The effectiveness of Mn(VII) for treatment of TBrBPA in real waters was confirmed. It is important to better understand the reactivity and toxicity of primary brominated products before Mn(VII) can be applied for treatment of TBrBPA-contaminated wastewater and source water.

  15. Hydrogen-bromine fuel cell advance component development

    NASA Technical Reports Server (NTRS)

    Charleston, Joann; Reed, James

    1988-01-01

    Advanced cell component development is performed by NASA Lewis to achieve improved performance and longer life for the hydrogen-bromine fuel cells system. The state-of-the-art hydrogen-bromine system utilizes the solid polymer electrolyte (SPE) technology, similar to the SPE technology developed for the hydrogen-oxygen fuel cell system. These studies are directed at exploring the potential for this system by assessing and evaluating various types of materials for cell parts and electrode materials for Bromine-hydrogen bromine environment and fabricating experimental membrane/electrode-catalysts by chemical deposition.

  16. NMR investigation of non-brominated and brominated epoxy ester prepolymers

    NASA Astrophysics Data System (ADS)

    Žigon, M.; Osredkar, U.; Šebenik, A.

    1992-03-01

    1H, 13C and two-dimensional NMR spectroscopy has been used to investigate the structure of epoxy ester prepolymers, based on non-brominated DGEBA-type or brominated DGETBBA-type epoxy resins, and on an oligomeric carboxylic acid. In the presence of a quaternary phosphonium salt, besides diglycidylether of bisphenol A (DGEBA) or diglycidylether of tetrabromobisphenol A (DGETBBA) and their higher oligomers, monoesters with characteristic R-CH 2-CH(OH)-CH 2-OCOR' groups were detected in prevailing quantities. In dependence of the epoxy-carboxy ratio, isomeric monoesters with hydroxymethyl groups, diesters and diols might also be present.

  17. Potential hazards of brominated carbon sorbents for mercury emission control.

    PubMed

    Bisson, Teresa M; Xu, Zhenghe

    2015-02-17

    Mercury is a toxic air pollutant, emitted from the combustion of coal. Activated Carbon (AC) or other carbon sorbent (CS) injection into coal combustion flue gases can remove elemental mercury through an adsorption process. Recently, a brominated CS with biomass ash as the carbon source (Br-Ash) was developed as an alternative for costly AC-based sorbent for mercury capture. After mercury capture, these sorbents are disposed in landfill, and the stability of bromine and captured mercury is of paramount importance. The objective of this study is to determine the fate of mercury and bromine from Br-Ash and brominated AC after their service. Mercury and bromine leaching tests were conducted using the standard toxicity characteristic leaching procedure (TCLP). The mercury was found to be stable on both the Br-Ash and commercial brominated AC sorbents, while the bromine leached into the aqueous phase considerably. Mercury pulse injection tests on the sorbent material after leaching indicate that both sorbents retain significant mercury capture capability even after the majority of bromine was removed. Testing of the Br-Ash sorbent over a wider range of pH and liquid:solid ratios resulted in leaching of <5% of mercury adsorbed on the Br-Ash. XPS analysis indicated more organically bound Br and less metal-Br bonds after leaching.

  18. The Addition of Bromine to 1,2-Diphenylethene

    ERIC Educational Resources Information Center

    Amburgey-Peters, Judith C.; Haynes, Leroy W.

    2005-01-01

    The bromination of 1,2-diphenylethene, using a variety of solvents and brominating agents, can be used in both introductory and advanced organic chemistry courses. The reactions can be used to illustrate the effects of changing solvents and reagents, as well as to reveal interesting aspects of organic reaction mechanisms.

  19. 40 CFR 721.10534 - Brominated aliphatic alcohol (generic).

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 40 Protection of Environment 32 2013-07-01 2013-07-01 false Brominated aliphatic alcohol (generic... Specific Chemical Substances § 721.10534 Brominated aliphatic alcohol (generic). (a) Chemical substance and... aliphatic alcohol (PMN P-12-260) is subject to reporting under this section for the significant new...

  20. 40 CFR 721.10534 - Brominated aliphatic alcohol (generic).

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 40 Protection of Environment 31 2014-07-01 2014-07-01 false Brominated aliphatic alcohol (generic... Specific Chemical Substances § 721.10534 Brominated aliphatic alcohol (generic). (a) Chemical substance and... aliphatic alcohol (PMN P-12-260) is subject to reporting under this section for the significant new...

  1. Fire-retardant coatings based on organic bromine/phenoxy or brominated epoxy systems

    SciTech Connect

    Hoffman, D.M.; Chiu, Ing L.

    1989-06-01

    Thin phenoxy and brominated epoxy/curing agent films were prepared by solvent casting on Mylar and Kapton. Thicknesses were approximated assuming volume additivity. Important parameters were uniformity of thickness, distribution of the bromine-containing fire retardant, adhesion to carrier substrate (either Mylar or Kapton), and uniformity of the coating, i.e., absence of pinholes, blush, blistering, etc. Wetting behavior was modified using fluoro, silicone or polyurea surfactants. Several solvent systems were examined and a ternary solvent system was ultimately used. Distribution of fire-retardant bromine was analyzed using electron microprobe, x-ray fluorescence and wet chemical methods. Significant discrepancies in the /mu/m-scale analyses of the microprobe measurements have not been resolved. Some of the brominated fire retardants were insoluble in the resin systems and the phase separation was immediately obvious. Similarly, some of the crystallizable epoxies could not be cast easily into homogeneous, amorphous films. Castings were made on a standard 8'' /times/ 10'' aluminum vacuum plate polished with jeweler's rouge prior to every casting. Solvent was removed in a forced air or vacuum oven. Removal and/or curing was accelerated with temperature. The fire-retardant bromine was required to be stable in alcohol/salt solutions. Final formulation used after a significant amount of testing was phenoxy resin PKHC in a ternary solvent system composed of methylethyl ketone, cellosolve acetate and toluene. Tetrabromobisphenol A was used as the flame retardant with FC-430 as surfactant. The dying schedule was 30 minutes at 150/degree/C. 4 refs., 6 figs., 3 tabs.

  2. Effects of milling brominated P-100 graphite fibers

    NASA Technical Reports Server (NTRS)

    Gaier, James R.; Dillehay, Michael E.; Hambourger, Paul D.

    1987-01-01

    Preliminary procedures have been developed for the ball milling of pristine and brominated P-100 graphite fibers. Because of the lubricative properties of graphite, large ball loads (50 percent by volume) are required. Use of 2-propanol as a milling medium enhances the efficiency of the process. The fibers, when allowed to settle from the milling medium, tend to be preferentially aligned with rather few fibers standing up. Milled, brominated P-100 fibers have resistivities that are indistinguishable from their pristine counterparts, apparently because of loss of bromine. This suggests that bromine would not be the intercalate of choice in applications where milled fibers of this type are required. It was found that brominated graphite fibers are stable in a wide variety of organic solvents.

  3. New infrared spectroscopic database for bromine nitrate

    NASA Astrophysics Data System (ADS)

    Wagner, Georg; Birk, Manfred

    2016-08-01

    Fourier transform infrared measurements of bromine nitrate have been performed in the spectral region 675-1400 cm-1 at 0.014 cm-1 spectral resolution. Absorption cross sections were derived from 38 spectra covering the temperature range from 203 to 296 K and air pressure range from 0 to 190 mbar. For line-by-line analysis, further spectra were recorded at 0.00094 cm-1 spectral resolution at 223 and 293 K. The sample was synthesized from ClONO2 and Br2. Band strengths of the bands ν3 around 803 cm-1 and ν2 around 1286 cm-1 were determined from three pure BrONO2 measurements at different temperatures and pressures. Number densities in the absorption cell were derived from pressure measurements of the purified sample taking into account small amounts of impurities determined spectroscopically. Resulting band strengths are Sν3 = 2.872(52) × 10-17 cm2 molec-1 cm-1 and Sν2 = 3.63(15) × 10-17 cm2 molec-1 cm-1. Absorption cross sections of all measurements were scaled to these band strengths. Further data reduction was achieved with an interpolation scheme based on two-dimensional polynomials in ln(pressure) and temperature. The database is well-suited for remote-sensing application and should reduce the atmospheric bromine nitrate error budget substantially.

  4. Are brominated flame retardants endocrine disruptors?

    PubMed

    Legler, Juliette; Brouwer, Abraham

    2003-09-01

    Brominated flame retardants (BFRs) are a group of compounds that have received much attention recently due to their similarity with "old" classes of organohalogenated compounds such as polychlorinated biphenyls (PCBs), in terms of their fate, stability in the environment and accumulation in humans and wildlife. Toxic effects, including teratogenicity, carcinogenicity and neurotoxicity, have been observed for some BFR congeners, in particular the brominated diphenyl ethers (BDEs). This concise review focuses on the potency of BFRs and to disrupt endocrine systems, and attempts to answer the question whether or not BFRs are endocrine disruptors. Evidence is provided on the disruption of the thyroid hormone system by BFRs, with particular emphasis on the BDEs, as most recent data is available on this class of flame retardants. Similar to the hydroxylated PCBs, in vitro mechanistic studies as well as animal experiments have demonstrated the effects of BDEs on thyroid hormone transport and metabolism. An overview of possible effects of BFRs on the estrogen system is also provided. Research gaps are outlined, as well as ongoing and future studies in the European community aimed at contributing to comprehensive risk assessments based on the endocrine-disrupting effects of BFRs.

  5. 40 CFR 415.290 - Applicability; description of the bromine production subcategory.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... bromine production subcategory. 415.290 Section 415.290 Protection of Environment ENVIRONMENTAL PROTECTION... CATEGORY Bromine Production Subcategory § 415.290 Applicability; description of the bromine production... bromine by the brine-mining process and by the Trona process....

  6. 40 CFR 415.290 - Applicability; description of the bromine production subcategory.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... bromine production subcategory. 415.290 Section 415.290 Protection of Environment ENVIRONMENTAL PROTECTION... CATEGORY Bromine Production Subcategory § 415.290 Applicability; description of the bromine production... bromine by the brine-mining process and by the Trona process....

  7. 40 CFR 415.290 - Applicability; description of the bromine production subcategory.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... bromine production subcategory. 415.290 Section 415.290 Protection of Environment ENVIRONMENTAL PROTECTION... CATEGORY Bromine Production Subcategory § 415.290 Applicability; description of the bromine production... bromine by the brine-mining process and by the Trona process....

  8. 40 CFR 415.290 - Applicability; description of the bromine production subcategory.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... bromine production subcategory. 415.290 Section 415.290 Protection of Environment ENVIRONMENTAL PROTECTION... CATEGORY Bromine Production Subcategory § 415.290 Applicability; description of the bromine production... bromine by the brine-mining process and by the Trona process....

  9. 40 CFR 415.290 - Applicability; description of the bromine production subcategory.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... bromine production subcategory. 415.290 Section 415.290 Protection of Environment ENVIRONMENTAL PROTECTION... CATEGORY Bromine Production Subcategory § 415.290 Applicability; description of the bromine production... bromine by the brine-mining process and by the Trona process....

  10. Use of Bromine and Bromo-Organic Compounds in Organic Synthesis.

    PubMed

    Saikia, Indranirekha; Borah, Arun Jyoti; Phukan, Prodeep

    2016-06-22

    Bromination is one of the most important transformations in organic synthesis and can be carried out using bromine and many other bromo compounds. Use of molecular bromine in organic synthesis is well-known. However, due to the hazardous nature of bromine, enormous growth has been witnessed in the past several decades for the development of solid bromine carriers. This review outlines the use of bromine and different bromo-organic compounds in organic synthesis. The applications of bromine, a total of 107 bromo-organic compounds, 11 other brominating agents, and a few natural bromine sources were incorporated. The scope of these reagents for various organic transformations such as bromination, cohalogenation, oxidation, cyclization, ring-opening reactions, substitution, rearrangement, hydrolysis, catalysis, etc. has been described briefly to highlight important aspects of the bromo-organic compounds in organic synthesis.

  11. Hydrogen-Bromine Flow Battery: Hydrogen Bromine Flow Batteries for Grid Scale Energy Storage

    SciTech Connect

    2010-10-01

    GRIDS Project: LBNL is designing a flow battery for grid storage that relies on a hydrogen-bromine chemistry which could be more efficient, last longer and cost less than today’s lead-acid batteries. Flow batteries are fundamentally different from traditional lead-acid batteries because the chemical reactants that provide their energy are stored in external tanks instead of inside the battery. A flow battery can provide more energy because all that is required to increase its storage capacity is to increase the size of the external tanks. The hydrogen-bromine reactants used by LBNL in its flow battery are inexpensive, long lasting, and provide power quickly. The cost of the design could be well below $100 per kilowatt hour, which would rival conventional grid-scale battery technologies.

  12. Bromine-Chlorine Coupling in the Antarctic Ozone Hole

    NASA Technical Reports Server (NTRS)

    Danilin, Michael Y.; Sze, Nien-Dak; Ko, Malcolm K. W.; Rodriquez, Jose M.; Prather, Michael J.

    1996-01-01

    The contribution from the chlorine and bromine species in the formation of the Antarctic ozone hole is evaluated. Since chlorine and bromine compounds are of different industrial origin, it is desirable, from a policy point of view, to be able to attribute chlorine-catalyzed loss of ozone with those reactions directly involving chlorine species, and likewise for bromine-catalyzed loss. In the stratosphere, however, most of the chemical families are highly coupled, and, for example, changes in the chlorine abundance will alter the partitioninig in other families and thus the rate of ozone loss. This modeling study examines formation of the Antarctic ozone hole for a wide range of bromine concentrations (5 - 25 pptv) and for chlorine concentrations typical of the last two decades (1.5, 2.5 and 3.5 ppbv). We follow the photochemical evolution of a single parcel of air, typical of the inner Antarctic vortex (50 mbar, 70 deg. S, NO(sub y) = 2 ppbv, with Polar Stratospheric Clouds(PSC)) from August 1 to November 1. For all of these ranges of chlorine and bromine loading, we would predict a substantial ozone hole (local depletion greater than 90%) within the de-nitrified, PSC- perturbed vortex. The contributions of the different catalytic cycles responsible for ozone loss are tabulated. The deep minimum in ozone is driven primarily by the chlorine abundance. As bromine levels decrease, the magnitude of the chlorine-catalyzed ozone loss increases to take up the slack. This is because bromine suppresses ClO by accelerating the conversion of ClO an Cl2O2 back to HCI. For this range of conditions, the local relative efficiency of ozone destruction per bromine atom to that per chlorine atom (alpha-factor) ranges from 33 to 55, decreasing with increase of bromine.

  13. Bromine content and brominated flame retardants in food and animal feed from the UK.

    PubMed

    Fernandes, A R; Mortimer, D; Rose, M; Smith, F; Panton, S; Garcia-Lopez, M

    2016-05-01

    Current occurrence data for polybrominated diphenyl ethers (PBDE) and hexa-bromocyclododecane (HBCD) measured in most commonly consumed foods (n = 156) and animal feeds (n = 51) sampled in the UK, demonstrates an ongoing ubiquity of these contaminants in human and animal diets. PBDE concentrations for the sum of 17 measured congeners ranged from 0.02 ng/g to 8.91 ng/g whole weight for food, and 0.11 ng/g to 9.63 ng/g whole weight for animal feeds. The highest concentration ranges, and mean values were detected in fish, processed foods and fish feeds. HBCD diastereomers (alpha-HBCD was the most commonly detected) generally occurred at lower concentrations (from <0.01 ng/g to 10.1 ng/g for food and <0.01 ng/g to 0.66 ng/g for animal feed) and less frequently than PBDEs, but tetrabromobisphenol A which was also measured, was rarely detected. The total bromine content of the samples was also determined in an attempt to use a mass balance approach to investigate some of these samples for the occurrence of novel and emerging BFRs. Although the approach was further refined by measuring organic bromine content, the concentrations of bromine were too high (in most cases by orders of magnitude) to allow use of the approach. A selected sub-set of samples was screened by GC-MS, for the presence of novel/emerging brominated flame retardants (PBT, TBX, PBEB, DBHCTD, HCTBPH and OBTMPI) but these were not detected at the higher limits of detection that result from full scan (GC-MS) screening. This data will contribute to the EU wide risk assessment on these contaminants.

  14. (Development of Bromine-77 from the LAMPF facility)

    SciTech Connect

    Not Available

    1989-01-01

    The objective of the work was to conduct the necessary studies required to evaluate the efficacy, potential benefit and role of bromine-77 labeled steroids in the detection and evaluation of treatment for hormone-dependent tumors. This report presents progress on the following tasks: An initial investigation concentrating on the radiobromination at carbon-6 or carbon-7 in selected simple steroids utilizing the nuclides, bromine-82 and bromine-77, analytical spectroscopy of radiolabeled compounds, and investigating the biodistribution, toxicology and tumor affinity of labeled agents.

  15. Ruthenium-Catalyzed meta-Selective C—H Bromination

    PubMed Central

    Teskey, Christopher J; Lui, Andrew Y W; Greaney, Michael F

    2015-01-01

    The first example of a transition-metal-catalyzed, meta-selective C–H bromination procedure is reported. In the presence of catalytic [{Ru(p-cymene)Cl2}2], tetrabutylammonium tribromide can be used to functionalize the meta C–H bond of 2-phenylpyridine derivatives, thus affording difficult to access products which are highly predisposed to further derivatization. We demonstrate this utility with one-pot bromination/arylation and bromination/alkenylation procedures to deliver meta-arylated and meta-alkenylated products, respectively, in a single step. PMID:26288217

  16. Alkaline reforming of brominated fire-retardant plastics: fate of bromine and antimony.

    PubMed

    Onwudili, Jude A; Williams, Paul T

    2009-02-01

    High-impact polystyrene (HIPS) flame retarded with decabromodiphenyl ether (DDE), has been reacted in supercritical water from 380 to 450 degrees C and 21.5 to 31.0 MPa pressure in a batch reactor. Different concentrations of sodium hydroxide additive were used in situ to neutralize the corrosive inorganic bromine species released during the reactions. It appeared that supercritical water conditions lowered the decomposition temperature of both the fire-retardant DDE and HIPS. The reaction products included oils (up to 76 wt%), char (up to 18 wt%) and gas (up to 2.4 wt%) which was mainly methane. The presence of the alkaline water led to up to 97 wt% debromination of the product oil, producing virtually bromine-free oil feedstock. The removal of antimony from the oil product during processing was of the order of 98 wt%. The oil consisted of many single- and multiple-ringed aromatic compounds, many of which had alkyl substituents and/or aliphatic C(n)-bridges (n=1-4). The major single-ringed compounds included toluene, xylenes, ethylbenzene, propylbenzene and alpha-methylstyrene. Bibenzyl (diphenylethane), stilbene, diphenylmethane, diphenylpropane, diphenylcyclopropane, diphenylpropene, diphenylbutane, diphenylbutene and diphenylbuta-1,3-diene were the major C(n)-bridged compounds. Diphenyl ether and acetophenone were the major oxygenated compounds found. The process thus has the potential to produce bromine-free and antimony-free oils from fire-retardant plastics.

  17. Existence state of bromine as an indicator of the source of brominated flame retardants in indoor dust.

    PubMed

    Suzuki, Go; Kida, Akiko; Sakai, Shin-ichi; Takigami, Hidetaka

    2009-03-01

    Indoor dust is an important medium for human exposure to brominated flame retardants (BFRs) such as polybrominated diphenyl ethers (PBDEs). In this study, we used micro X-ray fluorescence spectrometry (XRFS), digital optical microscopy, and gas chromatography-high resolution mass spectrometry to investigate the existence state of bromine as an indicator of the source of BFRs in indoor dusts and in dusts from the interior of televisions collected in Japan. By means of micro XRFS bromine mapping conducted at a 0.5-s dwell time, we were able to detect bromine levels as low as about 0.1% at each point of about a beam diameter of 50 microm across. The presence of fragments containing 1.0% or more bromine was confirmed in 27 of the 48 dust samples tested. Using magnified images of the fragments, we classified them roughly into particulates and fibrous substances. We analyzed PBDEs in the fragments containing high concentrations of bromine (> or = 0.1%) and confirmed that the fragments contained PBDEs, mainly BDE 209. Furthermore, to detect bromine concentrations < or = 0.1% in the dust samples, we analyzed the samples at a dwell time of 100 s to enhance the detection sensitivity of mapping; atthis dwell time, we confirmed the presence of bromine in the dust coating. Our results suggest that bromine is transferred from products to dust matrixes not only through miniaturization and subsequent direct migration into dust as plastic and textile fragments but also through other pathways such as vaporization and airborne transfer of microparticulates.

  18. Magnetic trapping of cold bromine atoms.

    PubMed

    Rennick, C J; Lam, J; Doherty, W G; Softley, T P

    2014-01-17

    Magnetic trapping of bromine atoms at temperatures in the millikelvin regime is demonstrated for the first time. The atoms are produced by photodissociation of Br2 molecules in a molecular beam. The lab-frame velocity of Br atoms is controlled by the wavelength and polarization of the photodissociation laser. Careful selection of the wavelength results in one of the pair of atoms having sufficient velocity to exactly cancel that of the parent molecule, and it remains stationary in the lab frame. A trap is formed at the null point between two opposing neodymium permanent magnets. Dissociation of molecules at the field minimum results in the slowest fraction of photofragments remaining trapped. After the ballistic escape of the fastest atoms, the trapped slow atoms are lost only by elastic collisions with the chamber background gas. The measured loss rate is consistent with estimates of the total cross section for only those collisions transferring sufficient kinetic energy to overcome the trapping potential.

  19. In search of stratospheric bromine oxide

    NASA Technical Reports Server (NTRS)

    Lestrade, John Patrick

    1986-01-01

    The Imaging Spectrometric Observatory (ISO) is capable of recording spectra in the wavelength range of 200 to 12000 Angstroms. Data from a recent Spacelab 1 ATLAS mission has imaged the terrestrial airglow at tangent ray heights of 90 and 150 km. These data contain information about trace atmospheric constituents such as bromine oxide (BrO), hydroxyl (OH), and chlorine dioxide (OClO). The abundances of these species are critical to stratospheric models of catalytic ozone destruction. Heretofore, very few observations were made especially for BrO. Software was developed to purge unwanted solar features from the airglow spectra. The next step is a measure of the strength of the emission features for BrO. The final analysis will yield the scale height of this important compound.

  20. Development of Bromine-77 from the LAMPF facility

    SciTech Connect

    Mettler, F.A. Jr.

    1982-01-01

    The objective of the work is to conduct the necessary studies required to evaluate the efficacy, potential benefit and role of bromine-77 labelled steroids in the detection and evaluation of treatment for hormone-dependent tumors. The synthetic goals of the project are to prepose estradiol derivatives which are labelled with bromine-77 at specific positions in the steroid nucleus. In addition, animal studies imaging studies, and cooperative studies are being conducted. (KJD)

  1. Gas transport in polybutadiene treated with aqueous bromine

    NASA Astrophysics Data System (ADS)

    Rein, D. H.; Baddour, R. F.; Cohen, R. E.

    1991-10-01

    Diffusion, solubility and permeability coefficients were measured for He, CO2, Ar and CH4 in polybutadiene (PB) and in polybutadiene reacted in the solid state to various extents with aqueous bromine. Analysis of the sorption curves and x ray emission spectra showed that the bromination created a heterogeneous membrane with an outer brominated skin and an unreacted core. At relatively low extent of bromination, the diffusion and permeability coefficients for CO2, Ar and CH4 became immeasurably small after about 3 percent bromination. The ideal separation factor for gas pairs with different molecular size increased with bromination, suggesting applications in gas separation processes. Tailoring the structure of existing commodity polymers through chemical modification is an attractive approach to improving the properties of membranes for gas separation and barrier applications. Systematic alterations of the polymer structure also provide a convenient route for studying the effects of molecular architecture on the permeability. Substitutions to the backbone or side chains affect the intrasegmental mobility and intersegmental chain packing, resulting in changes in gas diffusivity, solubility and permeability coefficients.

  2. Atmospheric bromine and ozone perturbations in the lower stratosphere

    NASA Technical Reports Server (NTRS)

    Yung, Y. L.; Pinto, J. P.; Watson, R. T.; Sander, S. P.

    1980-01-01

    The role of bromine compounds in the photochemistry of the natural and perturbed stratosphere has been reexamined using an expanded reaction scheme and the results of recent laboratory studies of several key reactions. The most important finding is that through the reaction BrO + ClO yielding Br + Cl + O2 there is a synergistic effect between bromine and chlorine which results in an efficient catalytic destruction of ozone in the lower stratosphere. One-dimensional photochemical model results indicate that BrO is the major bromine species throughout the stratosphere, followed by BrONO2, HBr, HOBr and Br. It is shown from the foregoing that bromine is more efficient than chlorine as a catalyst for destroying ozone, and the implications for stratospheric ozone of possible future growth in the industrial and agricultural use of bromine are discussed. Bromine concentrations of 20 pptv (2 x 10 to the -11th power), as suggested by recent observations, can decrease the present-day integrated ozone column density by 2.4%, and can enhance ozone depletion from steady-state chlorofluoromethane release at 1973 rates by a factor of 1.1-1.2.

  3. Brominated flame retardant exposure of aircraft personnel.

    PubMed

    Strid, Anna; Smedje, Greta; Athanassiadis, Ioannis; Lindgren, Torsten; Lundgren, Håkan; Jakobsson, Kristina; Bergman, Åke

    2014-12-01

    The use of brominated flame retardants (BFRs) such as polybrominated diphenyl ethers (PBDEs) in aircraft is the result of high fire safety demands. Personnel working in or with aircraft might therefore be exposed to several BFRs. Previous studies have reported PBDE exposure in flight attendants and in passengers. One other group that may be subjected to significant BFR exposure via inhalation, are the aircraft maintenance workers. Personnel exposure both during flights and maintenance of aircraft, are investigated in the present study. Several BFRs were present in air and dust sampled during both the exposure scenarios; PBDEs, hexabromocyclododecane (HBCDD), decabromodiphenyl ethane (DBDPE) and 1,2-bis (2,4,6-tribromophenoxy) ethane. PBDEs were also analyzed in serum from pilots/cabin crew, maintenance workers and from a control group of individuals without any occupational aircraft exposure. Significantly higher concentrations of PBDEs were found in maintenance workers compared to pilots/cabin crew and control subjects with median total PBDE concentrations of 19, 6.8 and 6.6 pmol g(-1) lipids, respectively. Pilots and cabin crew had similar concentrations of most PBDEs as the control group, except for BDE-153 and BDE-154 which were significantly higher. Results indicate higher concentrations among some of the pilots compared to the cabin crew. It is however, evident that the cabin personnel have lower BFR exposures compared to maintenance workers that are exposed to such a degree that their blood levels are significantly different from the control group.

  4. TSCA Work Plan Chemical Technical Supplement – Physicochemical Properties and Environmental Fate of the Brominated Phthalates Cluster (BPC) Chemicals

    EPA Pesticide Factsheets

    TSCA Work Plan Chemical Technical Supplement – Physicochemical Properties and Environmental Fate of the Brominated Phthalates Cluster (BPC) Chemicals -- Brominated Phthalates Cluster Flame Retardants.

  5. Probing the tropical tropopause layer for organic and inorganic bromine

    NASA Astrophysics Data System (ADS)

    Werner, Bodo; Pfeilsticker, Klaus; Atlas, Elliot; Cheung, Ross; Chipperfield, Martyn; Colosimo, Fedele; Deutschmann, Tim; Elkins, Jim; Fahey, David; Feng, Wu; Festa, James; Gao, Ru-Shan; Hossaini, Ryan; Navarro, Maria; Raecke, Rasmus; Scalone, Lisa; Spolaor, Max; Thornberry, Troy; Tsai, Catalina; Stutz, Jochen

    2016-04-01

    Bromine chemistry impacts the levels of ozone in the upper troposphere and the stratosphere. An accurate quantitative understanding of the sources, sinks, and chemical transformation of bromine species is thus important to understand the photochemistry and budget of bromine in the tropical upper troposphere, tropopause layer and lowermost stratosphere (UT/TTL/LS). These regions are also known to serve as a gateway for delivery of ozone depleting gases to the stratosphere. CH3Br, halons, short-lived organic bromine precursors (VSLS), such as CHBr3, CH2Br2, and possibly inorganic product gases have been identified as the main bromine gases delivered to the stratosphere. However, many important details of the transport and delivery of VSLS and inorganic bromine compounds through the TTL are still uncertain. Moreover, a number of chemical processes, including the transformation of the source gases and cycling of inorganic bromine species at low ambient temperature and on ice particles are also poorly understood. The presentation reports measurements of CH4, O3, NO2, and BrO performed by different instruments and techniques during the 2013 NASA-ATTREX flights in the TTL and LS. The interpretation of our measurements is supported by chemical transport model (SLIMCAT) simulations. SLIMCAT results, in conjunction with extensive radiative transfer calculations using the Monte Carlo model McArtim, also are used to improve retrieval of O3, NO2, and BrO concentrations from limb scattered sunlight measurements made with the Differential Optical Absorption Spectroscopy (DOAS) technique during ATTREX. The chemical transport model also allows us to attribute observed concentration variations to transport and to photochemical processes. When properly accounting for the transport-related concentration variations in methane and ozone, we find that measured BrO mostly agrees with model simulations. An exception are regions where the contribution of the short-lived CH2Br2 or the

  6. Dietary iodine and bromine intakes in Ukrainian subjects.

    PubMed

    Shiraishi, Kunio; Ko, Susumu; Muramatsu, Yasuyuki; Zamostyan, Pavlo V; Tsigankov, Nikolay Y

    2009-01-01

    Dietary iodine and bromine intakes in Ukrainian subjects were estimated in relation to the health effects on inhabitants after the Chernobyl accident. Two hundred and eighty-six total diets were collected from twenty-five regions for Ukrainians by a duplicate portion study. Iodine and bromine were rapidly determined by inductively coupled plasma mass spectrometry after chemical separation. The range, median, and geometric mean of iodine intakes were 2.86-698, 44.7, and 48.1 microg per person per day, respectively. Those of bromine were 0.627-16.9, 2.97, and 2.92 mg per person per day, respectively. Daily intakes of both elements in Ukrainians were lower than previously reported values. The iodine intake in areas contaminated by the Chernobyl accident was lower than that in non-contaminated areas. The low iodine intake in both areas would be related to the high prevalence of goiters throughout the whole country. The low bromine intakes indicated Ukrainians were not exposed to bromine-containing foods.

  7. Fate of higher brominated PBDEs in lactating cows.

    PubMed

    Kierkegaard, Amelie; Asplund, Lillemor; de Wit, Cynthia A; McLachlan, Michael S; Thomas, Gareth O; Sweetman, Andrew J; Jones, Kevin C

    2007-01-15

    Dietary intake studies of lower brominated diphenyl ethers (BDEs) have shown that fish and animal products are important vectors of human exposure, but almost no data exist for higher brominated BDEs. Therefore, the fate of hepta- to decaBDEs was studied in lactating cows exposed to a naturally contaminated diet by analyzing feed, feces, and milk samples from a previous mass balance study of PCB. Tissue distribution was studied in one cow slaughtered after the experiment. BDE-209 was the dominant congener in feed, organs, adipose tissues, and feces, but not in milk. In contrast to PCBs and lower brominated BDEs, concentrations of hepta- to decaBDEs in adipose tissue were 9-80 times higher than in milk fat and the difference increased with degree of bromination/log K(OW). The congener profiles in adipose tissue and feed differed; BDE-207, BDE-196, BDE-197, and BDE-182 accumulated to a surprisingly greater extent in the fat compared to their isomers, suggesting metabolic debromination of BDE-209 to these BDEs. The results indicate that meat rather than dairy product consumption may be an important human exposure route to higher brominated BDEs.

  8. What can bromine in ice cores tell us about Arctic sea ice in the past?

    NASA Astrophysics Data System (ADS)

    Vallelonga, Paul; Spolaor, Andrea; Maffazzoli, Niccolo; Kjær, Helle; Barbante, Carlo; Saiz-Lopez, Alfonso

    2016-04-01

    Bromine is of interest as a potential sea ice proxy due to its role in polar atmospheric chemistry, particularly the photochemical "bromine explosion" events which occur over the seasonal sea ice surface. A growing body of literature has demonstrated that bromine is reliably deposited and preserved in polar ice caps and can be used to investigate variability over timescales varying from seasonal to multimillenial. For sea ice reconstructions, bromine and sodium are usually evaluated with respect to their relative abundances in seawater. Competing processes of bromine enrichment due to the bromine explosion, and bromine depletion due to scavenging and deposition, must be taken into account when comparing results from coastal and inland sampling sites. We will review existing bromine-based sea ice reconstructions and present new data for locations from Svalbard, Severnaya Zemlya, Northwest Greenland (NEEM ice core) and central East Greenland (Renland ice core).

  9. Environmental monitoring of brominated flame retardants

    NASA Astrophysics Data System (ADS)

    Vagula, Mary C.; Kubeldis, Nathan; Nelatury, Charles F.

    2011-06-01

    Brominated flame retardants (BFRs) are synthetic organobromide compounds which inhibit ignition and combustion processes. Because of their immense ability to retard fire and save life and property, they have been extensively used in many products such as TVs, computers, foam, plastics etc. The five major classes of BFRs are tetrabromobisphenol-A (TBBPA), hexabromocyclododecane (HBCD), pentabromodiphenyl ether, octabromodiphenyl ether, and decabromodiphenyl ether. The last three are also commonly called PBDEs. BDE-85 and BDE-209 are the two prominent congeners of PBDEs and this study reports the adverse effects of these congeners in rodents. Exposure of rat sciatic nerves to 5 μg/mL and 20 μg/mL of BDE-85 and BDE-209 respectively lead to significant, concentration dependent reduction in nerve conduction function. Glucose absorption in the rat intestinal segments exposed to 5 μg/mL of BDE-85 and BDE-209 was significantly reduced for both the compounds tested. Lastly, mice when exposed to 0.25 mg/kg body weight for four days showed a disruption in oxidant and antioxidant equilibrium. The tissues namely liver and brain have shown increase in the levels of lipid hydroperoxides indicating oxidative stress. Moreover, all the protective enzymes namely superoxide dismutase (SOD), glutathione peroxidase (GPx), catalase, and glutathione S transferase (GST) have shown tissue specific alterations indicating the induction of damaging oxidative stress and setting in of lipid peroxidation in exposed animals. The results indicate monitoring of PBDEs in the environment is essential because levels as low as 5 μg/mL and 0.25 mg/kg body weight were able to cause damage to the functions of rodents.

  10. Interference by metabolites and the corresponding troubleshooting during the LC-MS/MS bioanalysis of G004, a bromine-containing hypoglycemic agent.

    PubMed

    Hu, Linlin; Ding, Li; Li, Xiaobing; Zhou, Na; Zhong, Shuisheng; Wu, Guanzhong; Zhang, Huibin

    2012-06-15

    The quantitative determination of drugs in bio-samples may be interfered by the drug-related metabolites during the high-throughput LC-MS/MS analysis. When quantifying bromine or chlorine containing compounds, the ⁸¹Br/³⁷Cl isotopic forms of their mono-hydroxylated metabolites after in-source dehydration could produce ions which are isobaric with the precursor ions of the parent compounds at the ⁷⁹Br/³⁵Cl isotopic form. In this report, we described the identification of an interfering hydroxylated metabolite of G004, a novel bromine-containing hypoglycemic agent, during LC-MS/MS analysis of plasma samples. Several different MRM transitions were tested and evaluated to minimize the metabolite influence on the quantification of G004. Furthermore, the standard addition method using incurred samples was used to evaluate the matrix effect caused by the interfering metabolite. The lower limit of quantitation of the established method was 0.2 ng/ml, which was 10 times lower than the existing one. The method was successfully applied to investigate the single-dosing pharmacokinetic profile of G004 in beagle dogs. The above results indicated that when quantifying chlorine or bromine containing compounds, evaluation of the interference from mono-hydroxylation or dehydrogenation metabolites should be undertaken, and if such metabolites existed, their impact on quantification of the parent compounds could be eliminated by the proper selection of the MRM transitions.

  11. Development of Bromine-77 from the LAMPF facility

    SciTech Connect

    Mettler, F.A.; Hylarides, M.

    1982-12-03

    The objective of the work is to conduct the necessary studies required to evaluate the efficacy, potential benefit and role of bromine-77 labelled steroids in the detection and evaluation of treatment for hormone-dependent tumors. The synthetic goals of 1982-3 included the synthesis estradiol derivatives which were radiohalogenated in the A- or C-ring with bromine-77 or bromine-82. Estradiol derivatives in which the radiohalogen was incorporated into the C-ring were prepared and purified with high specific activity. Biodistribution studies of the resultant compounds will be performed on rats in the near future. Various synthetic approaches toward estradiol which is radiohalogenated in the 1-position are discussed.

  12. The bromine content of micrometeorites - Arguments for stratospheric contamination

    NASA Astrophysics Data System (ADS)

    Rietmeijer, F. J. M.

    1993-04-01

    Bromine-salt nanocrystals are associated with a porous chondritic micrometeorite (W7029E5) that was collected in the lower stratosphere. These salt nanocrystals occur together with volcanic Na and K salt nanocrystals embedded in sulfuric acid droplets that were originally adhered to the particle. These materials were concentrated during hexane rinsing as part of routine curation procedures at the NASA Johnson Space Center Cosmic Dust Curatorial Facility. This observation is fortuitous to the extent that the concentration of nanocrystals and sulfuric acid is an experimental artifact of curation. If bromine is a stratospheric contaminant due to surface adsorption, there should be a positive linear relationship between the mass-normalized residence time and bromine content of individual micrometeorites. I show that the predicted correlation exists using a new model to calculate the stratospheric residence time of individual nonspherical micrometeorites in the slow-settling Wilson-Huang regime of the stratosphere.

  13. The bromine content of micrometeorites - Arguments for stratospheric contamination

    NASA Technical Reports Server (NTRS)

    Rietmeijer, Frans J. M.

    1993-01-01

    Bromine-salt nanocrystals are associated with a porous chondritic micrometeorite (W7029E5) that was collected in the lower stratosphere. These salt nanocrystals occur together with volcanic Na and K salt nanocrystals embedded in sulfuric acid droplets that were originally adhered to the particle. These materials were concentrated during hexane rinsing as part of routine curation procedures at the NASA Johnson Space Center Cosmic Dust Curatorial Facility. This observation is fortuitous to the extent that the concentration of nanocrystals and sulfuric acid is an experimental artifact of curation. If bromine is a stratospheric contaminant due to surface adsorption, there should be a positive linear relationship between the mass-normalized residence time and bromine content of individual micrometeorites. I show that the predicted correlation exists using a new model to calculate the stratospheric residence time of individual nonspherical micrometeorites in the slow-settling Wilson-Huang regime of the stratosphere.

  14. 40 CFR 180.519 - Bromide ion and residual bromine; tolerances for residues.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 40 Protection of Environment 23 2010-07-01 2010-07-01 false Bromide ion and residual bromine... Tolerances § 180.519 Bromide ion and residual bromine; tolerances for residues. (a) General. The food additives, bromide ion and residual bromine, may be present in water, potable in accordance with...

  15. 40 CFR 180.519 - Bromide ion and residual bromine; tolerances for residues.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 40 Protection of Environment 25 2013-07-01 2013-07-01 false Bromide ion and residual bromine... Tolerances § 180.519 Bromide ion and residual bromine; tolerances for residues. (a) General. The food additives, bromide ion and residual bromine, may be present in water, potable in accordance with...

  16. 40 CFR 180.519 - Bromide ion and residual bromine; tolerances for residues.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 40 Protection of Environment 25 2012-07-01 2012-07-01 false Bromide ion and residual bromine... Tolerances § 180.519 Bromide ion and residual bromine; tolerances for residues. (a) General. The food additives, bromide ion and residual bromine, may be present in water, potable in accordance with...

  17. 40 CFR 180.519 - Bromide ion and residual bromine; tolerances for residues.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 40 Protection of Environment 24 2011-07-01 2011-07-01 false Bromide ion and residual bromine... Tolerances § 180.519 Bromide ion and residual bromine; tolerances for residues. (a) General. The food additives, bromide ion and residual bromine, may be present in water, potable in accordance with...

  18. 40 CFR 180.519 - Bromide ion and residual bromine; tolerances for residues.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 40 Protection of Environment 24 2014-07-01 2014-07-01 false Bromide ion and residual bromine... Tolerances § 180.519 Bromide ion and residual bromine; tolerances for residues. (a) General. The food additives, bromide ion and residual bromine, may be present in water, potable in accordance with...

  19. Method and apparatus for maintaining the pH in zinc-bromine battery systems

    DOEpatents

    Grimes, Patrick G.

    1985-09-10

    A method and apparatus for maintaining the pH level in a zinc-bromine battery features reacting decomposition hydrogen with bromine in the presence of a catalyst. The catalyst encourages the formation of hydrogen and bromine ions. The decomposition hydrogen is therefore consumed, alloying the pH of the system to remain substantially at a given value.

  20. Temporal effects in porcine skin following bromine vapor exposure.

    PubMed

    Price, Jennifer A; Rogers, James V; Wendling, Morgan Q S; Plahovinsak, Jennifer L; Perry, Mark R; Reid, Frances M; Kiser, Robyn C; Graham, John S

    2011-09-01

    Bromine is an industrial chemical that causes severe cutaneous burns. When selecting or developing effective treatments for bromine burns, it is important to understand the molecular mechanisms of tissue damage and wound healing. This study investigated the effect of cutaneous bromine vapor exposure on gene expression using a weanling swine burn model by microarray analysis. Ventral abdominal sites were exposed to a mean calculated bromine vapor concentration of 0.51 g/L for 7 or 17 min. At 6 h, 48 h, and 7 days post-exposure, total RNA from skin samples was isolated, processed, and analyzed with Affymetrix GeneChip® Porcine Genome Arrays (N = 3 per experimental group). Differences in gene expression were observed with respect to exposure duration and sampling time. Ingenuity Pathways Analysis (IPA) revealed four common biological functions (cancer, cellular movement, cell-to-cell signaling and interaction, and tissue development) among the top ten functions of each experimental group, while canonical pathway analysis revealed 9 genes (ARG2, CCR1, HMOX1, ATF2, IL-8, TIMP1, ESR1, HSPAIL, and SELE) that were commonly shared among four significantly altered signaling pathways. Among these, the transcripts encoding HMOX1 and ESR1 were identified using IPA as common potential therapeutic targets for Phase II/III clinical trial or FDA-approved drugs. The present study describes the transcriptional responses to cutaneous bromine vapor exposure identifying molecular networks and genes that could serve as targets for developing therapeutics for bromine-induced skin injury.

  1. Spring measurements of tropospheric bromine at Barrow, Alaska

    NASA Astrophysics Data System (ADS)

    Sturges, William T.; Schnell, Russell C.; Dutton, Geoffrey S.; Garcia, Samuel R.; Lind, John A.

    1993-02-01

    The partitioning of bromine in the lower troposphere between particulate, inorganic gaseous, and organic gaseous phases was measured during the arctic spring. Rapid photochemical production of particulate Br from organic gaseous Br was indicated by (1) an inverse correlation between particulate bromide and organic gaseous bromine, (2) a diurnal cycle in the ratio of these two phases, and (3) a diurnal cycle in the ratio of organic gaseous Br to Cl. Organic gaseous Br and Cl were correlated indicating a common, possibly marine, source.

  2. Recent developments in the analysis of brominated flame retardants and brominated natural compounds.

    PubMed

    Covaci, Adrian; Voorspoels, Stefan; Ramos, Lourdes; Neels, Hugo; Blust, Ronny

    2007-06-15

    This article reviews recent literature on the analysis of brominated flame retardants (BFRs) and brominated natural compounds (BNCs). The main literature sources are reviews from the last five years and research articles reporting new analytical developments published between 2003 and 2006. Sample pretreatment, extraction, clean-up and fractionation, injection techniques, chromatographic separation, detection methods, quality control and method validation are discussed. Only few new techniques, such as solid-phase microextraction (SPME) or pressurized liquid extraction (PLE), have been investigated for their ability of combining the extraction and clean-up steps. With respect to the separation of BFRs, the most important developments were the use of comprehensive two-dimensional gas chromatography for polybrominated diphenyl ethers (PBDEs) and the growing tendency for liquid-chromatographic techniques for hexabromocyclododecane (HBCD) stereoisomers and of tetrabromobisphenol-A (TBBP-A). At the detection stage, mass spectrometry (MS) has been developed as well-established and reliable technology in the identification and quantification of BFRs. A growing attention has been paid to quality assurance. Interlaboratory exercises directed towards BFRs have grown in popularity and have enabled laboratories to validate analytical methods and to guarantee the quality of their results. The analytical procedures used for the identification and characterization of several classes of BNCs, such as methoxylated polybrominated diphenyl ethers (MeO-PBDEs) (also metabolites of PBDEs), halogenated methyl or dimethyl bipyrroles (DBPs), are reviewed here for the first time. These compounds were generally identified during the routine analysis of BFRs and have received little attention until recently. For each topic, an overview is presented of its current status.

  3. Sensing and inactivation of Bacillus anthracis Sterne by polymer-bromine complexes.

    PubMed

    D'Angelo, Paola A; Bromberg, Lev; Hatton, T Alan; Wilusz, Eugene

    2016-08-01

    We report on the performance of brominated poly(N-vinylpyrrolidone) (PVP-Br), brominated poly(ethylene glycol) (PEG-Br), and brominated poly(allylamine-co-4-aminopyridine) (PAAm-APy-Br) for their ability to decontaminate Bacillus anthracis Sterne spores in solution while also allowing for the sensing of the spores. The polymers were brominated by bromine using carbon tetrachloride or potassium tribromide as solvents, with bromine loadings ranging from 1.6 to 4.2 mEq/g of polymer. B. anthracis Sterne spores were exposed to increasing concentrations of brominated polymers for 5 min, while the kinetics of the sporicidal activity was assessed. All brominated polymers demonstrated spore log-kills of 8 within 5 min of exposure at 12 mg/mL aqueous polymer concentration. Sensing of spores was accomplished by measuring the release of dipicolinic acid (DPA) from the spore using time-resolved fluorescence. Parent, non-brominated polymers did not cause any release of DPA and the spores remained viable. In contrast, spores exposed to the brominated polymers were inactivated and the release of DPA was observed within minutes of exposure. Also, this release of DPA continued for a long time after spore inactivation as in a controlled release process. The DPA release was more pronounced for spores exposed to brominated PVP and brominated PEG-8000 compared to brominated PAAm-APy and brominated PEG-400. Using time-resolved fluorescence, we detected as low as 2500 B. anthracis spores, with PEG-8000 being more sensitive to low spore numbers. Our results suggest that the brominated polymers may be used effectively as decontamination agents against bacterial spores while also providing the sensing capability.

  4. Bromine in Interplanetary Dust Particles (IDPs): Evidence for Stratospheric Contamination

    NASA Astrophysics Data System (ADS)

    Rietmeijer, F. J. M.

    1992-07-01

    Chondritic IDPs that are collected in the lower stratosphere are enriched in bromine: up to 40 x CI in an individual IDP [1]. The average enrichment is 19 x CI [2]. Volatile element enrichments in chondritic IDPs show a general increase with increased element volatility [1,2] which is consistent with solar nebula condensation models. However, the bromine enrichment is markedly up from the general volatile element enrichment trend. Stratospheric bromine derives from anthropogenic and volcanic activities and micrometeoroid ablation and evaporation [3]. It is possible that a portion or all bromine in IDPs is stratospheric surface contamination. In this case there should be an inverse correlation between bromine content and IDP size [1,4]. This correlation is not obvious because it may be complicated by the different ability of exposed IDP surfaces to adsorb volatile elements [1]. To evaluate this model it is important to know whether bromine occurs in a distinct mineral phase [5] or in a surface layer that might not survive the curatorial rinsing procedure. Another factor is the IDP stratospheric residence time. In my continued AEM analyses of ultrathin CP IDP sections, I recently observed round Br-containing grains associated with CP IDP W7029E5. These grains (11.6-744 nm in diameter) have a volatile matrix with abundant nanocrystals. Their bulk composition shows the presence of Na, K, Br, Cl, and S. Polycrystalline rings in their diffraction patterns are consistent with KBrO(sub)3, KCl, Na(sub)2SO(sub)3 and Na(sub)2S(sub)2 [Gail Fraundorf, written comm., 1991]. These round grains resemble sulfuric acid droplets associated with silica grains in other CP IDPs [6]. The sulfuric acid was washed off the silica grain surface during curatorial hexane rinsing of IDPs. The AEM data confirm a Br-bearing layer on W7029E5. This study is the first, and so far only, observation of Br-bearing material associated with chondritic IDPs in support of a stratospheric bromine surface

  5. Airborne measurements of organic bromine compounds in the Pacific tropical tropopause layer

    PubMed Central

    Navarro, Maria A.; Atlas, Elliot L.; Saiz-Lopez, Alfonso; Rodriguez-Lloveras, Xavier; Kinnison, Douglas E.; Lamarque, Jean-Francois; Tilmes, Simone; Filus, Michal; Harris, Neil R. P.; Meneguz, Elena; Ashfold, Matthew J.; Manning, Alistair J.; Cuevas, Carlos A.; Schauffler, Sue M.; Donets, Valeria

    2015-01-01

    Very short-lived brominated substances (VSLBr) are an important source of stratospheric bromine, an effective ozone destruction catalyst. However, the accurate estimation of the organic and inorganic partitioning of bromine and the input to the stratosphere remains uncertain. Here, we report near-tropopause measurements of organic brominated substances found over the tropical Pacific during the NASA Airborne Tropical Tropopause Experiment campaigns. We combine aircraft observations and a chemistry−climate model to quantify the total bromine loading injected to the stratosphere. Surprisingly, despite differences in vertical transport between the Eastern and Western Pacific, VSLBr (organic + inorganic) contribute approximately similar amounts of bromine [∼6 (4−9) parts per thousand] to the stratospheric input at the tropical tropopause. These levels of bromine cause substantial ozone depletion in the lower stratosphere, and any increases in future abundances (e.g., as a result of aquaculture) will lead to larger depletions. PMID:26504212

  6. Airborne measurements of organic bromine compounds in the Pacific tropical tropopause layer.

    PubMed

    Navarro, Maria A; Atlas, Elliot L; Saiz-Lopez, Alfonso; Rodriguez-Lloveras, Xavier; Kinnison, Douglas E; Lamarque, Jean-Francois; Tilmes, Simone; Filus, Michal; Harris, Neil R P; Meneguz, Elena; Ashfold, Matthew J; Manning, Alistair J; Cuevas, Carlos A; Schauffler, Sue M; Donets, Valeria

    2015-11-10

    Very short-lived brominated substances (VSLBr) are an important source of stratospheric bromine, an effective ozone destruction catalyst. However, the accurate estimation of the organic and inorganic partitioning of bromine and the input to the stratosphere remains uncertain. Here, we report near-tropopause measurements of organic brominated substances found over the tropical Pacific during the NASA Airborne Tropical Tropopause Experiment campaigns. We combine aircraft observations and a chemistry-climate model to quantify the total bromine loading injected to the stratosphere. Surprisingly, despite differences in vertical transport between the Eastern and Western Pacific, VSLBr (organic + inorganic) contribute approximately similar amounts of bromine [∼6 (4-9) parts per trillion] [corrected] to the stratospheric input at the tropical tropopause. These levels of bromine cause substantial ozone depletion in the lower stratosphere, and any increases in future abundances (e.g., as a result of aquaculture) will lead to larger depletions.

  7. Estimation of the residual bromine concentration after disinfection of cooling water by statistical evaluation.

    PubMed

    Megalopoulos, Fivos A; Ochsenkuehn-Petropoulou, Maria T

    2015-01-01

    A statistical model based on multiple linear regression is developed, to estimate the bromine residual that can be expected after the bromination of cooling water. Make-up water sampled from a power plant in the Greek territory was used for the creation of the various cooling water matrices under investigation. The amount of bromine fed to the circuit, as well as other important operational parameters such as concentration at the cooling tower, temperature, organic load and contact time are taken as the independent variables. It is found that the highest contribution to the model's predictive ability comes from cooling water's organic load concentration, followed by the amount of bromine fed to the circuit, the water's mean temperature, the duration of the bromination period and finally its conductivity. Comparison of the model results with the experimental data confirms its ability to predict residual bromine given specific bromination conditions.

  8. Development of a circulating zinc-bromine battery, phase 2

    NASA Astrophysics Data System (ADS)

    Bellows, R.; Einstein, H.; Grimes, P.; Kantner, E.; Malachesky, P. A.; Newby, K.; Tsien, H.; Young, A.

    1983-10-01

    This report summarizes Phase 2 of a multi-phase program aimed at developing Exxon's circulating zinc-bromine battery into an advanced energy storage system. Previous work at Exxon had developed a basic zinc-bromine battery system approach. This approach utilizes carbon-plastic electrodes in a bipolar stack design, a circulating electrolyte with separable bromine complexes, and shunt current protection. Phase 2 was highlighted by the successful scale-up and demonstration of a 20 kWh zinc-bromine battery module. Important technology improvements were demonstrated in the areas of extended life cycling, low cost stack technology, high power/high efficiency supported electrolytes, and system auxiliaries. The basic technology was augmented via increases in parametric testing, materials testing, and electrolyte studies. Production cost estimates from Phase 1 ($28/kWh in 1980) were projected to an OEM price of $37/kWh using the A.D. Little costing method. A design has been developed for a prototype 20 kWh energy storage system which will be delivered to Sandia National laboratories in 1983 near the completion of Phase 3.

  9. [Detection of bromine uptake in cadavers from seawater].

    PubMed

    Powitz, G

    1992-01-01

    Pieces of animal and human lungs were placed in seawater. The fluids pressed of it produced in X-ray fluorescence analysis bromine concentrations, which exceeded the physiological level. These experiments created the supposition to interpret correctly relevant findings in the victims of flight accidents.

  10. 40 CFR 721.3420 - Brominated arylalkyl ether.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... CONTROL ACT SIGNIFICANT NEW USES OF CHEMICAL SUBSTANCES Significant New Uses for Specific Chemical Substances § 721.3420 Brominated arylalkyl ether. Link to an amendment published at 79 FR 34637, June 18, 2014. (a) Chemical substances and significant new uses subject to reporting. (1) The chemical...

  11. ENHANCED FORMATION OF CHLORINATED PICS BY THE ADDITION OF BROMINE

    EPA Science Inventory

    A systematic series of experiments were performed on a pilot-scale rotary kiln incinerator simulator in which liquid surrogate wastes containing varied levels of chlorine and bromine were burned. The surrogate wastes used were a series of mixtures of methylene chloride and methyl...

  12. Regiodefined synthesis of brominated hydroxyanthraquinones related to proisocrinins

    PubMed Central

    Roy, Joyeeta; Mal, Tanushree; Jana, Supriti

    2016-01-01

    Summary Dibromobenzoisofuranone 12, synthesized in six steps, was regiospecifically annulated with 5-substituted cyclohexenones 13/36 in the presence of LiOt-Bu to give brominated anthraquinones 14/38 in good yields. Darzens condensation of 30 was shown to give chain-elongated anthraquinone 32. Alkaline hydrolysis of 38 furnished 39 representing desulfoproisocrinin F. PMID:27340445

  13. Isotopic Biogeochemistry

    NASA Technical Reports Server (NTRS)

    Hayes, J. M.

    1985-01-01

    An overview is provided of the biogeochemical research. The funding, productivity, personnel and facilities are reviewed. Some of the technical areas covered are: carbon isotopic records; isotopic studies of banded iron formations; isotope effects in microbial systems; studies of organic compounds in ancient sediments; and development in isotopic geochemistry and analysis.

  14. Non-standard isotope production and applications at Washington University

    NASA Astrophysics Data System (ADS)

    McCarthy, Timothy J.; McCarthy, Deborah W.; Laforest, Richard; Bigott, Heather M.; Wüst, Frank; Reichert, David E.; Lewis, Michael R.; Welch, Michael J.

    2001-07-01

    The positron emitting radionuclides, oxygen-15, nitrogen-13, carbon-11, and fluorine-18 have been produced at Washington University for many years utilizing two biomedical cyclotrons; a Cyclotron Corporation CS15 and a Japan Steel Works 16/8 cyclotron. In recent years we have become interested in the production of non-standard PET isotopes. We were initially interested in copper-64 production using the 64Ni(p,n)64Cu nuclear reaction, but now apply this technique to other positron emitting copper isotopes, copper-60 and copper-61. Copper-64 is being produced routinely and made available to other institutions. In 1999 over ten Curies of copper-64 were produced, making copper available to thirteen institutions, as well as research groups at Washington University. We are currently developing methods for the routine productions of other PET radioisotopes of interest, these include; bromine-76, bromine-77, iodine-124, gallium-66, and technetium-94m.

  15. A Simulation of Bromoform's Contribution to Stratospheric Bromine

    NASA Technical Reports Server (NTRS)

    Nielsen, J. Eric; Douglass, Anne R.; Einaudi, Franco (Technical Monitor)

    2000-01-01

    Many chlorinated and brominated compounds that are inert in the troposphere are destroyed in the stratosphere and act as an in-situ source of stratospheric reactive chlorine and bromine. Other halogenated compounds that are reactive in the troposphere might contribute to the stratosphere's halogen budget in two ways. First, like their unreactive companions, rapid convective transport might carry them to the upper troposphere and make them available for subsequent advection by the mean circulation into the stratosphere before they are oxidized or photolyzed. Second, it is more likely that they are destroyed in the troposphere, and the chlorine and bromine that is released might then be transported to the stratosphere. We evaluate the relative influence of these processes on stratospheric bromine in a three-dimensional chemistry and transport model which simulates the distribution of bromoform (CHBr3). CHBr3 is parameterized as a short-lived, ocean-surface source gas whose destruction by photolysis and reaction with hydroxyl (OH) in the troposphere and stratosphere yields inorganic bromine (Br(sub y)). Many of the observed features of CHBr3 are simulated well, and comparisons with observations are used to show that the model represents aspects of transport in the upper troposphere and lower stratosphere that are critical to the evaluation. In particular, the model maintains the observed troposphere-stratosphere distinctness in transport pathways and reproduces the observed seasonal dependence of the mixture of air in the middle- and high-latitude lowermost stratosphere. We estimate that adding CHBr3 to models which already include the long-lived organic brominated compounds (halons and methyl bromide) will increase the simulated stratospheric mass of Br(sub y) by about 15 percent. In-situ stratospheric destruction of CHBr3 produces Br(sub y) in amounts which are comparable to that transported into the stratosphere after photolysis and oxidation of CHBr3 in the

  16. High Resolution Coherent 3d Spectroscopy of Bromine

    NASA Astrophysics Data System (ADS)

    Strangfeld, Benjamin R.; Wells, Thresa A.; House, Zuri R.; Chen, Peter C.

    2013-06-01

    The high resolution gas phase electronic spectrum of bromine is rather congested due to many overlapping vibrational and rotational transitions with similar transition frequencies, and also due to isotopomeric effects. Expansion into the second dimension will remove some of this congestion; however through the implementation of High Resolution Coherent 3D Spectroscopy, the density of peaks is further reduced by at least two orders of magnitude. This allows for the selective examination of a small number of spatially resolved multidimensional bands, separated by vibrational quantum number and by isotopomer, which facilitates the fitting of many rovibrational peaks in bromine. The ability to derive information about the molecular constants for the electronic states involved will be discussed.

  17. The crystal structure and superconducting properties of monatomic bromine.

    PubMed

    Duan, Defang; Meng, Xing; Tian, Fubo; Chen, Changbo; Wang, Liancheng; Ma, Yanming; Cui, Tian; Liu, Bingbing; He, Zhi; Zou, Guangtian

    2010-01-13

    The crystal structure and superconducting properties of monatomic bromine under high pressure have been studied by first-principles calculations. We have found the following phase transition sequence with increasing pressure: from body-centered orthorhombic (bco, phase II) to body-centered tetragonal structure (bct, phase III) at 126 GPa, then to face-centered cubic structure (fcc, phase IV) at 157 GPa, which is stable at least up to 300 GPa. The calculated superconducting critical temperature T(c) = 1.46 K at 100 GPa is consistent with the experimental value of 1.5 K. In addition, our results of T(c) decrease with increasing pressure in all the monatomic phases of bromine, similar to monatomic iodine. Further calculations show that the decrease of λ with pressure in phase IV is mainly attributed to the weakening of the 'soft' vibrational mode caused by pressure.

  18. Novel brominated metabolites from Bryozoa: a functional analysis.

    PubMed

    Maltseva, Arina L; Kotenko, Olga N; Kutyumov, Vladimir A; Matvienko, Darya A; Shavarda, Alexey L; Winson, Michael K; Ostrovsky, Andrew N

    2016-11-29

    Marine invertebrates are a promising source of novel natural products with biological activities. The phylum Bryozoa is relatively under-investigated in this context, although a number of compounds with medical potential has been discovered in recent years. Here, we report on the novel group of brominated metabolites from the bryozoan Terminoflustra membranaceatruncata, including analysis of biological activities of the tribrominated terminoflustrindole A (Cm-1) and the structures of the related dibrominated variants terminoflustrindoles B and C. Terminoflustrindole A was previously shown to have fungicidal properties. Although they vary by just one bromine group in each case from terminoflustrindole A, in this study, we report that terminoflustrindoles B and C exhibit no antimicrobial activity in the same assays. In addition to displaying antifungal activity, Terminoflustrindole A was also found to exhibit potent cytotoxic activity when tested against tumour cell lines. The gradient distribution of this compound within the bryozoan colony was demonstrated using LC-MS-analysis.

  19. Zinc-bromine battery design for electric vehicles

    SciTech Connect

    Bellows, R.; Grimes, P.; Einstein, H.; Kantner, E.; Malachesky, P.; Newby, K.

    1982-01-01

    Design projections for zinc-bromine batteries are attractive for electric vehicle applications in terms of low manufacturing costs ($28/kWh) and good performance characteristics. Zinc-bromine batery projections (60 to 80 Wh/kg, 130 to 200 W/kg) compare favorably to both current lead acid batteries and proposed advanced battery candidates. The performance of recently developed battery components with 1200 cm/sup 2/ electrodes in a 120V, 10 kWh module is described. Similarly constructed smaller scale (600 cm/sup 2/) components have shown lifetimes exceeding 400 cycles and the ability to follow both regenerative braking (J227aD) and random cycling regimes. Initial dynamometer evaluations of full scale 20 kWh batteries is expected in early 1984.

  20. New Methods for Labeling RGD Peptides with Bromine-76

    PubMed Central

    Lang, Lixin; Li, Weihua; Jia, Hong-Mei; Fang, De-Cai; Zhang, Shushu; Sun, Xilin; Zhu, Lei; Ma, Ying; Shen, Baozhong; Kiesewetter, Dale O.; Niu, Gang; Chen, Xiaoyuan

    2011-01-01

    Direct bromination of the tyrosine residues of peptides and antibodies with bromine-76, to create probes for PET imaging, has been reported. For peptides that do not contain tyrosine residues, however, a prosthetic group is required to achieve labeling via conjugation to other functional groups such as terminal α-amines or lysine ε-amines. The goal of this study was to develop new strategies for labeling small peptides with Br-76 using either a direct labeling method or a prosthetic group, depending on the available functional group on the peptides. A new labeling agent, N-succinimidyl-3-[76Br]bromo-2,6-dimethoxybenzoate ([76Br]SBDMB) was prepared for cyclic RGD peptide labeling. N-succinimidyl-2, 6-dimethoxybenzoate was also used to pre-attach a 2, 6-dimethoxybenzoyl (DMB) moiety to the peptide, which could then be labeled with Br-76. A competitive cell binding assay was performed to determine the binding affinity of the brominated peptides. PET imaging of U87MG human glioblastoma xenografted mice was performed using [76Br]-BrE[c(RGDyK)]2 and [76Br]-BrDMB-E[c(RGDyK)]2. An ex vivo biodistribution assay was performed to confirm PET quantification. The mechanisms of bromination reaction between DMB-c(RGDyK) and the brominating agent CH3COOBr were investigated with the SCRF-B3LYP/6-31G* method with the Gaussian 09 program package. The yield for direct labeling of c(RGDyK) and E[c(RGDyK)]2 using chloramine-T and peracetic acid at ambient temperature was greater than 50%. The yield for [76Br]SBDMB was over 60% using peracetic acid. The conjugation yields for labeling c(RGDfK) and c(RGDyK) were over 70% using the prosthetic group at room temperature. Labeling yield for pre-conjugated peptides was over 60%. SDMB conjugation and bromination did not affect the binding affinity of the peptides with integrin receptors. Both [76Br]Br-E[c(RGDyK)]2 and [76Br]BrDMB-E[c(RGDyK)]2 showed high tumor uptake in U87MG tumor bearing mice. The specificity of the imaging tracers was

  1. Single-run determination of polybrominated diphenyl ethers (PBDEs) di- to deca-brominated in fish meal, fish oil and fish feed by isotope dilution: application of automated sample purification and gas chromatography/ion trap tandem mass spectrometry (GC/ITMS).

    PubMed

    Blanco, Sonia Lucía; Vieites, Juan M

    2010-07-05

    The present paper describes the application of automated cleanup and fractionation procedures of the Power Prep system (Fluid Management Systems) for the determination of polybrominated diphenyl ethers (PBDEs) in feeding stuffs and fish meal and oil. Gas chromatography (GC) separation followed by ion trap tandem mass spectrometry detection in EI mode (ITMS) allowed the analysis of di- to deca-BDEs in the samples matrices used in fish aquaculture. The method developed enabled the determination of 26 native PBDE congeners and 11 (13)C(12)-labelled congeners, including deca-BDE 209, in a single-run analysis, using isotope dilution. The automated cleanup, consisting of a succession of multilayer silica and basic alumina columns previously applied by Wyrzykowska et al. (2009) [28] in combustion flue gas, was successfully applied in our complex matrices. The method allowed an increase in productivity, i.e. lower time was required to process samples, and simultaneous purification of several samples was achieved at a time, reducing analyst dedication and human error input. Average recoveries of 43-96% were obtained. GC/ITMS can overcome the complexity originating from the sample matrix, eliminating matrix effects by tandem MS, to enable the detection of congeners penta- to nona-BDEs where interferent masses were present. The provisional detection limits, estimated in the samples, were 5-30 pg for di-, tri-, tetra-, and penta-BDEs, 20-65 pg for hexa-, hepta-, octa- and nona-BDEs, and 105 pg for deca-BDE. Reduction of deca-BDE 209 blank values is of concern to ongoing research. Good accuracy was obtained by application of the whole procedure, representing an efficient, low-cost and fast alternative for routine analyses.

  2. Analysis of Ah receptor pathway activation by brominated flame retardants.

    PubMed

    Brown, David J; Van Overmeire, Ilse; Goeyens, Leo; Denison, Michael S; De Vito, Michael J; Clark, George C

    2004-06-01

    Brominated flame-retardants (BFRs) are used as additives in plastics to decrease the rate of combustion of these materials, leading to greater consumer safety. As the use of plastics has increased, the production and use of flame-retardants has also grown. Many BFRs are persistent and have been detected in environmental samples, raising concerns about the biological/toxicological risk associated with their use. Most BFRs appear to be non-toxic, however there is still some concern that these compounds, or possible contaminants in BFRs mixtures could interact with cellular receptors. In this study we have examined the interaction of decabromodiphenyl ether, Firemaster BP4A (tetrabromobisphenol A), Firemaster PHT4 (tetrabromophthalic anhydride), hexabromobenzene, pentabromotoluene, decabromobiphenyl, Firemaster BP-6 (2,2',4,4',5,5'-hexabromobiphenyl) and possible contaminants of BFR mixtures with the Ah receptor. Receptor binding and activation was examined using the Gel Retardation Assay and increased expression of dioxin responsive genes was detected using the reporter gene based CALUX assay. The results demonstrate the ability of BFRs to activate the AhR signal transduction pathway at moderate to high concentrations as assessed using both assays. AhR-dependent activation by BFRs may be due in part to contaminants present in commercial/technical mixtures. This was suggested by our comparative analysis of Firemaster BP-6 versus its primary component 2,2',4,4',5,5'-hexabromobiphenyl. Some technical mixtures of brominated flame-retardants contain brominated biphenyls, dioxins or dibenzofurans as contaminants. When tested in the CALUX assay these compounds were found to be equivalent to, or more active than their chlorinated analogues. Relative effective potency values were determined from dose response curves for these brominated HAHs.

  3. Eosinophils generate brominating oxidants in allergen-induced asthma

    PubMed Central

    Wu, Weijia; Samoszuk, Michael K.; Comhair, Suzy A.A.; Thomassen, Mary Jane; Farver, Carol F.; Dweik, Raed A.; Kavuru, Mani S.; Erzurum, Serpil C.; Hazen, Stanley L.

    2000-01-01

    Eosinophils promote tissue injury and contribute to the pathogenesis of allergen-triggered diseases like asthma, but the chemical basis of damage to eosinophil targets is unknown. We now demonstrate that eosinophil activation in vivo results in oxidative damage of proteins through bromination of tyrosine residues, a heretofore unrecognized pathway for covalent modification of biologic targets in human tissues. Mass spectrometric studies demonstrated that 3-bromotyrosine serves as a specific “molecular fingerprint” for proteins modified through the eosinophil peroxidase-H2O2 system in the presence of plasma levels of halides. We applied a localized allergen challenge to model the effects of eosinophils and brominating oxidants in human lung injury. Endobronchial biopsy specimens from allergen-challenged lung segments of asthmatic, but not healthy control, subjects demonstrated significant enrichments in eosinophils and eosinophil peroxidase. Baseline levels of 3-bromotyrosine in bronchoalveolar lavage (BAL) proteins from mildly allergic asthmatic individuals were modestly but not statistically significantly elevated over those in control subjects. After exposure to segmental allergen challenge, lung segments of asthmatics, but not healthy control subjects, exhibited a >10-fold increase in BAL 3-bromotyrosine content, but only two- to threefold increases in 3-chlorotyrosine, a specific oxidation product formed by neutrophil- and monocyte-derived myeloperoxidase. These results identify reactive brominating species produced by eosinophils as a distinct class of oxidants formed in vivo. They also reveal eosinophil peroxidase as a potential therapeutic target for allergen-triggered inflammatory tissue injury in humans. PMID:10811853

  4. Sensitivity of Ozone to Bromine in the Lower Stratosphere

    NASA Technical Reports Server (NTRS)

    Salawitch, R. J.; Weisenstein, D. K.; Kovalenko, L. J.; Sioris, C. E.; Wennberg, P. O.; Chance, K.; Ko, M. K. W.; McLinden, C. A.

    2005-01-01

    Measurements of BrO suggest that inorganic bromine (Br(sub y)) at and above the tropopause is 4 to 8 ppt greater than assumed in models used in past ozone trend assessment studies. This additional bromine is likely carried to the stratosphere by short-lived biogenic compounds and their decomposition products, including tropospheric BrO. Including this additional bromine in an ozone trend simulation increases the computed ozone depletion over the past approx.25 years, leading to better agreement between measured and modeled ozone trends. This additional Br(sub y) (assumed constant over time) causes more ozone depletion because associated BrO provides a reaction partner for ClO, which increases due to anthropogenic sources. Enhanced Br(sub y) causes photochemical loss of ozone below approx.14 km to change from being controlled by HO(sub x) catalytic cycles (primarily HO2+O3) to a situation where loss by the BrO+HO2 cycle is also important.

  5. Budget of Methyl Bromide in the Atmosphere: Isotopic Constraints

    NASA Astrophysics Data System (ADS)

    Bill, M.; Miller, L. G.; Rhew, R. C.; Goldstein, A. H.

    2001-12-01

    Bromine radicals contribute significantly to stratospheric ozone loss through coupled reactions with ClO, HO2, and NO2 radicals. Bromine is approximately 40-100 times more effective, atom for atom, at destroying ozone than chlorine. For instance, Br coupled reactions are responsible for 30 to 50% of the total ozone loss in the polar vortex. The largest source of bromine to the stratosphere is methyl bromide (CH3Br). CH3Br has a concentration in the troposphere of about 10 pptv, a total estimated lifetime of 0.6 to 0.9 years, and has the highest concentration of any long lived organobromine. Unlike chlorofluorocarbons, which are produced entirely by humans, methyl bromide is produced by both anthropogenic and natural processes. We are developing the use of stable isotopes to constrain the budget of CH3Br through quantification of the source signatures and the isotopic fractionations associated with sinks. The largest natural sources appear to be biological production in oceans ( ~35%), biomass burning ( ~13%), and salt marshes ( ~10%). Thus far, the only natural emissions to be isotopically characterized is from salt marsh plants. Carbon isotopic ratios of CH3Br emitted from the salt marsh have a strong diurnal variation from -65\\permil during daytime when emission rates are highest to -12\\permil at night when emissions are ~13% of the daytime rates. The \\delta13C weighted mean of salt marsh emission is -43\\permil CH3Br. Anthropogenically produced CH3Br is used for fumigation of soils, harvested crops and structures, and represents approximately 30% of the total source flux. The fumigation of harvested crops and structures constitutes approximately one third of the anthropogenic source to the atmosphere and, because the release rate of applied CH3Br approaches 100%, it should have a mean isotopic composition equal to industrially manufactured CH3Br, -54.4\\permil. However during soil fumigation, some of the CH3Br is consumed insitu causing isotopic fractionation

  6. Elemental Bromine Production by TiO2 Photocatalysis and/or Ozonation.

    PubMed

    Parrino, Francesco; Camera Roda, Giovanni; Loddo, Vittorio; Palmisano, Leonardo

    2016-08-22

    Significant production of elemental bromine (Br2 ) was observed for the first time when treating bromide containing solutions at acidic pH, with TiO2 photocatalyst, ozone, or a combination thereof. Br2 selectivities up to approximately 85 % were obtained and the corresponding bromine mass balance values satisfied. The process is general and may be applied at a laboratory scale for green bromination reactions, or industrially as a cheap, safe, and environmentally sustainable alternative to the currently applied bromine production methods.

  7. Bromination of hydrocarbons with CBr4, initiated by light-emitting diode irradiation

    PubMed Central

    Ohtani, Bunsho; Kikushima, Kotaro

    2013-01-01

    Summary The bromination of hydrocarbons with CBr4 as a bromine source, induced by light-emitting diode (LED) irradiation, has been developed. Monobromides were synthesized with high efficiency without the need for any additives, catalysts, heating, or inert conditions. Action and absorption spectra suggest that CBr4 absorbs light to give active species for the bromination. The generation of CHBr3 was confirmed by NMR spectroscopy and GC–MS spectrometry analysis, indicating that the present bromination involves the homolytic cleavage of a C–Br bond in CBr4 followed by radical abstraction of a hydrogen atom from a hydrocarbon. PMID:24062826

  8. Specific heat of pristine and brominated graphite fibers, composites and HOPG. [Highly Oriented Pyrolytic Graphite

    NASA Technical Reports Server (NTRS)

    Hung, Ching-Chen; Maciag, Carolyn

    1987-01-01

    Differential scanning calorimetry was used to obtain specific heat values of pristine and brominated P-100 graphite fibers and brominated P-100/epoxy composite as well as pristine and brominated highly oriented pyrolytic graphite (HOPG) for comparison. Based on the experimental results obtained, specific heat values are calculated for several different temperatures, with a standard deviation estimated at 1.4 percent of the average values. The data presented here are useful in designing heat transfer devices (such as airplane de-icing heaters) from bromine fibers.

  9. Inorganic bromine in the marine boundary layer: a critical review

    NASA Astrophysics Data System (ADS)

    Sander, R.; Keene, W. C.; Pszenny, A. A. P.; Arimoto, R.; Ayers, G. P.; Baboukas, E.; Cainey, J. M.; Crutzen, P. J.; Duce, R. A.; Hönninger, G.; Huebert, B. J.; Maenhaut, W.; Mihalopoulos, N.; Turekian, V. C.; van Dingenen, R.

    2003-06-01

    The cycling of inorganic bromine in the marine boundary layer (mbl) has received increased attention in recent years. Bromide, a constituent of sea water, is injected into the atmosphere in association with sea-salt aerosol by breaking waves on the ocean surface. Measurements reveal that supermicrometer sea-salt aerosol is depleted in bromine by about 50% relative to conservative tracers, whereas marine submicrometer aerosol is often enriched in bromine. Model calculations, laboratory studies, and field observations strongly suggest that these depletions reflect the chemical transformation of particulate bromide to reactive inorganic gases that influence the processing of ozone and other important constituents of marine air. However, currently available techniques cannot reliably quantify many \\chem{Br}-containing compounds at ambient concentrations and, consequently, our understanding of inorganic Br cycling over the oceans and its global significance are uncertain. To provide a more coherent framework for future research, we have reviewed measurements in marine aerosol, the gas phase, and in rain. We also summarize sources and sinks, as well as model and laboratory studies of chemical transformations. The focus is on inorganic bromine over the open oceans, excluding the polar regions. The generation of sea-salt aerosol at the ocean surface is the major tropospheric source producing about 6.2 Tg/a of bromide. The transport of Br from continents (as mineral aerosol, and as products from biomass-burning and fossil-fuel combustion) can be of local importance. Transport of degradation products of long-lived Br-containing compounds from the stratosphere and other sources contribute lesser amounts. Available evidence suggests that, following aerosol acidification, sea-salt bromide reacts to form Br2 and BrCl that volatilize to the gas phase and photolyze in daylight to produce atomic Br and Cl. Subsequent transformations can destroy tropospheric ozone, oxidize

  10. Inorganic bromine in the marine boundary layer: a critical review

    NASA Astrophysics Data System (ADS)

    Sander, R.; Keene, W. C.; Pszenny, A. A. P.; Arimoto, R.; Ayers, G. P.; Baboukas, E.; Cainey, J. M.; Crutzen, P. J.; Duce, R. A.; Hönninger, G.; Huebert, B. J.; Maenhaut, W.; Mihalopoulos, N.; Turekian, V. C.; van Dingenen, R.

    2003-09-01

    The cycling of inorganic bromine in the marine boundary layer (mbl) has received increased attention in recent years. Bromide, a constituent of sea water, is injected into the atmosphere in association with sea-salt aerosol by breaking waves on the ocean surface. Measurements reveal that supermicrometer sea-salt aerosol is substantially depleted in bromine (often exceeding 50%) relative to conservative tracers, whereas marine submicrometer aerosol is often enriched in bromine. Model calculations, laboratory studies, and field observations strongly suggest that the supermicrometer depletions reflect the chemical transformation of particulate bromide to reactive inorganic gases that influence the processing of ozone and other important constituents of marine air. Mechanisms for the submicrometer enrichments are not well understood. Currently available techniques cannot reliably quantify many Br containing compounds at ambient concentrations and, consequently, our understanding of inorganic Br cycling over the oceans and its global significance are uncertain. To provide a more coherent framework for future research, we have reviewed measurements in marine aerosol, the gas phase, and in rain. We also summarize sources and sinks, as well as model and laboratory studies of chemical transformations. The focus is on inorganic bromine over the open oceans outside the polar regions. The generation of sea-salt aerosol at the ocean surface is the major tropospheric source producing about 6.2 Tg/a of bromide. The transport of Br from continents (as mineral aerosol, and as products from biomass-burning and fossil-fuel combustion) can be of local importance. Transport of degradation products of long-lived Br containing compounds from the stratosphere and other sources contribute lesser amounts. Available evidence suggests that, following aerosol acidification, sea-salt bromide reacts to form Br2 and BrCl that volatilize to the gas phase and photolyze in daylight to produce atomic

  11. Detection of bromine by ICP-oa-ToF-MS following photochemical vapor generation.

    PubMed

    Sturgeon, Ralph E

    2015-03-03

    A unique flow-through photochemical reactor is utilized for the generation of volatile methyl bromide from aqueous solutions of bromide and bromate ions in a medium of 2% acetic acid containing 3000 μg/mL NH4Cl. The volatile product is transported to a thin-film gas-liquid phase separator and directed to an inductively coupled plasma (ICP) tine-of-flight mass spectrometer for detection and quantitation using either of the (79)Br or (81)Br isotopes. Utilizing a sample flow rate of 3.3 mL/min and a 13 s irradiation time, a detection limit of 0.14 ng/mL is achieved, yielding a 17-fold enhancement over conventional solution nebulization. The estimated generation efficiency of 95% provides for a significant increase in analyte transport efficiency to the ICP. Precision of replicate measurement is 2.5% (RSD) at 20 ng/mL. The methodology was validated by successful determination of bromine in reference materials, including IRMM (BCR-611) low level bromide in groundwater, NIST SRM 1568b Rice Flour, and SRM 1632 bituminous coal.

  12. 40 CFR 721.10416 - Brominated polyphenyl ether (generic) (P-11-264).

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ...) (P-11-264). 721.10416 Section 721.10416 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY... Specific Chemical Substances § 721.10416 Brominated polyphenyl ether (generic) (P-11-264). (a) Chemical... as brominated polyphenyl ether (PMN P-11-264) is subject to reporting under this section for...

  13. 40 CFR 721.10416 - Brominated polyphenyl ether (generic) (P-11-264).

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ...) (P-11-264). 721.10416 Section 721.10416 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY... Specific Chemical Substances § 721.10416 Brominated polyphenyl ether (generic) (P-11-264). (a) Chemical... as brominated polyphenyl ether (PMN P-11-264) is subject to reporting under this section for...

  14. The Evolution of a Green Chemistry Laboratory Experiment: Greener Brominations of Stilbene

    ERIC Educational Resources Information Center

    McKenzie, Lallie C.; Huffman, Lauren M.; Hutchison, James E.

    2005-01-01

    The use of green metrics to compare three bromination laboratory procedures demonstrates the effectiveness of an incremental greening process for chemistry curricula. Due to this process, the bromination of alkenes can be introduced to students through the use of a safe, effective, modern practice.

  15. Fundamental mechanisms of DNA radiosensitization: damage induced by low-energy electrons in brominated oligonucleotide trimers.

    PubMed

    Park, Yeunsoo; Polska, Katarzyna; Rak, Janusz; Wagner, J Richard; Sanche, Léon

    2012-08-16

    The replacement of nucleobases with brominated analogs enhances DNA radiosensitivity. We examine the chemistry of low-energy electrons (LEEs) in this sensitization process by experiments with thin films of the oligonucleotide trimers TBrXT, where BrX = 5-BrU (5-bromouracil), 5-BrC (5-bromocytosine), 8-BrA (8-bromoadenine), or 8-BrG (8-bromoguanine). The products induced from irradiation of thin (∼ 2.5 nm) oligonucleotide films, with 10 eV electrons, under ultrahigh vacuum (UHV) are analyzed by HPLC-UV. The number of damaged brominated trimers ranges from about 12 to 15 × 10(-3) molecules per incident electron, whereas under the identical conditions, these numbers drop to 4-7 × 10(-3) for the same, but nonbrominated oligonucleotides. The results of HPLC analysis show that the main degradation pathway of trinucleotides containing brominated bases involve debromination (i.e., loss of the bromine atom and its replacement with a hydrogen atom). The electron-induced sum of products upon bromination increases by factors of 2.1 for the pyrimidines and 3.2 for the purines. Thus, substitution of any native nucleobase with a brominated one in simple models of DNA increases LEE-induced damage to DNA and hence its radiosensitivity. Furthermore, besides the brominated pyrimidines that have already been tested in clinical trials, brominated purines not only appear to be promising sensitizers for radiotherapy, but could provide a higher degree of radiosensitization.

  16. Obtaining the Iodine Value of Various Oils via Bromination with Pyridinium Tribromide

    ERIC Educational Resources Information Center

    Simurdiak, Michael; Olukoga, Olushola; Hedberg, Kirk

    2016-01-01

    A laboratory exercise was devised that allows students to rapidly and fairly accurately determine the iodine value of oleic acid. This method utilizes the addition of elemental bromine to the unsaturated bonds in oleic acid, due to bromine's relatively fast reaction rate compared to that of the traditional Wijs solution method. This method also…

  17. Bayesian statistical modeling of disinfection byproduct (DBP) bromine incorporation in the ICR database.

    PubMed

    Francis, Royce A; Vanbriesen, Jeanne M; Small, Mitchell J

    2010-02-15

    Statistical models are developed for bromine incorporation in the trihalomethane (THM), trihaloacetic acids (THAA), dihaloacetic acid (DHAA), and dihaloacetonitrile (DHAN) subclasses of disinfection byproducts (DBPs) using distribution system samples from plants applying only free chlorine as a primary or residual disinfectant in the Information Collection Rule (ICR) database. The objective of this study is to characterize the effect of water quality conditions before, during, and post-treatment on distribution system bromine incorporation into DBP mixtures. Bayesian Markov Chain Monte Carlo (MCMC) methods are used to model individual DBP concentrations and estimate the coefficients of the linear models used to predict the bromine incorporation fraction for distribution system DBP mixtures in each of the four priority DBP classes. The bromine incorporation models achieve good agreement with the data. The most important predictors of bromine incorporation fraction across DBP classes are alkalinity, specific UV absorption (SUVA), and the bromide to total organic carbon ratio (Br:TOC) at the first point of chlorine addition. Free chlorine residual in the distribution system, distribution system residence time, distribution system pH, turbidity, and temperature only slightly influence bromine incorporation. The bromide to applied chlorine (Br:Cl) ratio is not a significant predictor of the bromine incorporation fraction (BIF) in any of the four classes studied. These results indicate that removal of natural organic matter and the location of chlorine addition are important treatment decisions that have substantial implications for bromine incorporation into disinfection byproduct in drinking waters.

  18. [Study on modes of occurrence of bromine in coals using sequential chemical extraction procedure].

    PubMed

    Peng, Bing-Xian; Wu, Dai-She; Li, Ping

    2011-07-01

    Modes of occurrence of bromine in eight coals from Sichuan and Chongqing were studied using inductively coupled plasma spectrometry and sequential chemical extraction. The results showed that the bromine mainly occur the water-soluble, ion exchangeable, carbonate, Fe-Mn oxides and organic fraction in these coals, which average total extraction rate was 88.2%. In bituminous coal and anthracite, the mean relative amount was 22.3% and 20.0% for organic bromine, 14.0% and 19.2% for the bromine of carbonate bound and almost equal for the bromine from water soluble and Fe-Mn oxidizes. The ion exchangeable bromine may be mainly adsorbed to organic matter in these coals. The relative amount of bromine in various modes of occurrence may not be very closely related to its sedimentary environment during the formation of coal. Bromine in coals from Sichuan and Chongqing should be paid more attention because its potential leachable rate was 36.62% - 86.80% and potential leachable content was 7.092- 20.10 microg/g.

  19. A Multistep Synthesis Incorporating a Green Bromination of an Aromatic Ring

    ERIC Educational Resources Information Center

    Cardinal, Pascal; Greer, Brandon; Luong, Horace; Tyagunova, Yevgeniya

    2012-01-01

    Electrophilic aromatic substitution is a fundamental topic taught in the undergraduate organic chemistry curriculum. A multistep synthesis that includes a safer and greener method for the bromination of an aromatic ring than traditional bromination methods is described. This experiment is multifaceted and can be used to teach students about…

  20. Determination of iodine and bromine in coal and atmospheric particles by inductively coupled plasma mass spectrometry.

    PubMed

    Sun, Mingxing; Gao, Yunchuan; Wei, Biwen; Wu, Xiaowei

    2010-04-15

    Bromine and iodine in atmospheric particles or coal can cause environmental problems such as destruction of ozone in the atmosphere; therefore, the presence of these compounds has recently received increased attention. Here, a rapid and reliable method for the simultaneous determination of total bromine and iodine using ICP-MS analysis is described. Samples were dissolved in mixtures of 5 mL of HNO(3) and 2 mL of H(2)O(2) in a high pressure microwave digester. The solution was then oxidized by per-sulfate (Na(2)S(2)O(8)) in addition to a small amount of silver nitrate, after which the total bromine and iodine were measured simultaneously by ICP-MS. The signal memory effects of bromine and iodine during analysis were effectively decreased by washing with a new mixture agent (2% alcohol acidic solution, pH 1-2 adjusted with HCl). The detection limits for bromine and iodine using this method were about 3.2 microg L(-1) and 1.1 microg L(-1), respectively. Additionally, the spike recoveries were between 78.7% and 121% for bromine and iodine analysis, while the relative standard deviations ranged from 4.3% to 9.7%, and from 1.5% to 3.4% for bromine and iodine, respectively. The results of this study indicate that the method described here is suitable for the analysis of micro-amounts of bromine and iodine in atmospheric particles and coal samples.

  1. 40 CFR 721.10280 - Benzene ethenyl-, polymer with 1,3-butadiene, brominated.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 40 Protection of Environment 32 2013-07-01 2013-07-01 false Benzene ethenyl-, polymer with 1,3... Specific Chemical Substances § 721.10280 Benzene ethenyl-, polymer with 1,3-butadiene, brominated. (a... benzene ethenyl-, polymer with 1,3-butadiene, brominated (PMN P-10-476; CAS No. 1195978-93-8)) is...

  2. 40 CFR 721.10280 - Benzene ethenyl-, polymer with 1,3-butadiene, brominated.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 40 Protection of Environment 31 2014-07-01 2014-07-01 false Benzene ethenyl-, polymer with 1,3... Specific Chemical Substances § 721.10280 Benzene ethenyl-, polymer with 1,3-butadiene, brominated. (a... benzene ethenyl-, polymer with 1,3-butadiene, brominated (PMN P-10-476; CAS No. 1195978-93-8)) is...

  3. Isotope separation

    DOEpatents

    Bartlett, Rodney J.; Morrey, John R.

    1978-01-01

    A method and apparatus is described for separating gas molecules containing one isotope of an element from gas molecules containing other isotopes of the same element in which all of the molecules of the gas are at the same electronic state in their ground state. Gas molecules in a gas stream containing one of the isotopes are selectively excited to a different electronic state while leaving the other gas molecules in their original ground state. Gas molecules containing one of the isotopes are then deflected from the other gas molecules in the stream and thus physically separated.

  4. 40 CFR 721.10625 - Distillation bottoms, alkylated benzene by-product, brominated and bromo diphenyl alkane (generic).

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... benzene by-product, brominated and bromo diphenyl alkane (generic). 721.10625 Section 721.10625 Protection... Distillation bottoms, alkylated benzene by-product, brominated and bromo diphenyl alkane (generic). (a... generically as distillation bottoms, alkylated benzene by-product, brominated and bromo diphenyl alkane...

  5. 40 CFR 721.10625 - Distillation bottoms, alkylated benzene by-product, brominated and bromo diphenyl alkane (generic).

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... benzene by-product, brominated and bromo diphenyl alkane (generic). 721.10625 Section 721.10625 Protection... Distillation bottoms, alkylated benzene by-product, brominated and bromo diphenyl alkane (generic). (a... generically as distillation bottoms, alkylated benzene by-product, brominated and bromo diphenyl alkane...

  6. Levels of brominated diphenylether, dibenzo-P-dioxin, and dibenzofuran in flue gases of a municipal waste combustor

    EPA Science Inventory

    Due to the extensive use of brominated flame retardants (BFRs), including brominated diphenylether (BDE) formulations, for various domestic and industrial applications, the presence of brominated chemicals in the waste stream is to be expected for decades. As much as 40% to 50% o...

  7. Theoretical performance of hydrogen-bromine rechargeable SPE fuel cell

    NASA Technical Reports Server (NTRS)

    Savinell, Robert F.; Fritts, S. D.

    1987-01-01

    A mathematical model was formulated to describe the performance of a hydrogen-bromine fuel cell. Porous electrode theory was applied to the carbon felt flow-by electrode and was coupled to theory describing the solid polymer electrolyte (SPE) system. Parametric studies using the numerical solution to this model were performed to determine the effect of kinetic, mass transfer, and design parameters on the performance of the fuel cell. The results indicate that the cell performance is most sensitive to the transport properties of the SPE membrane. The model was also shown to be a useful tool for scale-up studies.

  8. Dissociation rate of bromine diatomics in an argon heat bath

    NASA Technical Reports Server (NTRS)

    Razner, R.; Hopkins, D.

    1973-01-01

    The evolution of a collection of 300 K bromine diatomics embedded in a heat bath of argon atoms at 1800 K was studied by computer, and a dissociation-rate constant for the reaction Br2 + BR + Ar yields Br + Ar was determined. Previously published probability distributions for energy and angular momentum transfers in classical three-dimensional Br2-Ar collisions were used in conjunction with a newly developed Monte Carlo scheme for this purpose. Results are compared with experimental shock-tube data and the predictions of several other theoretical models. A departure from equilibrium is obtained which is significantly greater than that predicted by any of these other theories.

  9. Future chlorine-bromine loading and ozone depletion

    NASA Technical Reports Server (NTRS)

    Prather, Michael J.; Ibrahim, Abdel Moneim; Sasaki, Toru; Stordal, Frode; Visconti, Guido

    1991-01-01

    The prediction of future ozone requires three elements: (1) a scenario for the net emissions of chemically and radiatively active trace gases from the land and oceans; (2) a global atmospheric model that projects the accumulation of these gases; and (3) a chemical transport model that describes the distribution of ozone for a prescribed atmospheric composition and climate. This chapter, of necessity, presents models for all three elements and focuses on the following: (1) atmospheric abundance of chlorine and bromine in the form of halocarbons; and (2) the associated perturbations to stratospheric ozone.

  10. Environmental analysis of higher brominated diphenyl ethers and decabromodiphenyl ethane.

    PubMed

    Kierkegaard, Amelie; Sellström, Ulla; McLachlan, Michael S

    2009-01-16

    Methods for environmental analysis of higher brominated diphenyl ethers (PBDEs), in particular decabromodiphenyl ether (BDE209), and the recently discovered environmental contaminant decabromodiphenyl ethane (deBDethane) are reviewed. The extensive literature on analysis of BDE209 has identified several critical issues, including contamination of the sample, degradation of the analyte during sample preparation and GC analysis, and the selection of appropriate detection methods and surrogate standards. The limited experience with the analysis of deBDethane suggests that there are many commonalities with BDE209. The experience garnered from the analysis of BDE209 over the last 15 years will greatly facilitate progress in the analysis of deBDethane.

  11. Theoretical performance of hydrogen-bromine rechargeable SPE fuel cell

    NASA Astrophysics Data System (ADS)

    Savinell, R. F.; Fritts, S. D.

    1988-04-01

    A mathematical model was formulated to describe the performance of a hydrogen-bromine fuel cell. Porous electrode theory was applied to the carbon felt flow-by electrode and was coupled to theory describing the solid polymer electrolyte (SPE) system. Parametric studies using the numerical solution to this model were performed to determine the effect of kinetic, mass transfer, and design parameters on the performance of the fuel cell. The results indicate that the cell performance is most sensitive to the transport properties of the SPE membrane. The model was also shown to be a useful tool for scale-up studies.

  12. Theoretical performance of hydrogen-bromine rechargeable SPE fuel cell

    NASA Astrophysics Data System (ADS)

    Savinell, Robert F.; Fritts, S. D.

    1987-09-01

    A mathematical model was formulated to describe the performance of a hydrogen-bromine fuel cell. Porous electrode theory was applied to the carbon felt flow-by electrode and was coupled to theory describing the solid polymer electrolyte (SPE) system. Parametric studies using the numerical solution to this model were performed to determine the effect of kinetic, mass transfer, and design parameters on the performance of the fuel cell. The results indicate that the cell performance is most sensitive to the transport properties of the SPE membrane. The model was also shown to be a useful tool for scale-up studies.

  13. The effect of length and diameter on the resistivity of bromine intercalated graphite fibers

    NASA Technical Reports Server (NTRS)

    Gaier, James R.

    1989-01-01

    The resistivity of bromine intercalated graphite fibers has been shown to vary with both the diameter and the length of the fibers. This is due to bromine depletion from the fiber surface. Model calculations assuming a 1.0 micron bromine depletion zone for P-100, and 3.0 microns for vapor-grown graphite fibers fit the respective diameter dependence of their resistivities quite well. Length dependence data imply a bromine depletion zone along the length of P-100 fibers which is also a few microns, but that of vapor grown fibers appears to be as large as 300 microns. Despite these values, microfilaments, which are much smaller than the expected depletion zones, do form residual bromine intercalation compounds with resistivities about one-half of their pristine value.

  14. New radiopaque acrylic bone cement. II. Acrylic bone cement with bromine-containing monomer.

    PubMed

    Rusu, M C; Ichim, I C; Popa, M; Rusu, M

    2008-07-01

    Bromine-containing methacrylate, 2-(2-bromopropionyloxy) ethyl methacrylate (BPEM), had been used in the formulation of acrylic radiopaque cements. The effect of this monomer incorporated into the liquid phase of acrylic bone cement, on the curing parameters, thermal properties, water absorption, density, compression tests and radiopacity was studied. A decrease of maximum temperature and an increase of the setting time were observed with the addition of the bromine-containing monomer in the radiolucent cement composition. Adding BPEM in radiolucent acrylic bone cements composition results in the decrease of glass transition temperature and increase of its thermal stability. Acrylic bone cements modified with bromine-containing comonomer are characterized by polymerization shrinkage lower than the radiolucent cement. Addition of bromine-containing comonomer in radiolucent acrylic bone cement composition determines the increase of compressive strength. Acrylic bone cements modified with bromine-containing comonomer proved to be radiopaque.

  15. Alkane bromination revisited: "reproportionation" in gas-phase methane bromination leads to higher selectivity for CH3Br at moderate temperatures.

    PubMed

    Lorkovic, Ivan M; Sun, Shouli; Gadewar, Sagar; Breed, Ashley; Macala, Gerald S; Sardar, Amin; Cross, Sarah E; Sherman, Jeffrey H; Stucky, Galen D; Ford, Peter C

    2006-07-20

    The reaction of methane and bromine is a mildly exothermic and exergonic example of free radical alkane activation. We show here that the reaction of methane and bromine (CH4:Br2 > or = 1) may yield either a kinetically or a thermodynamically determined bromomethane product distribution and proceeds in two main phases between 450 and 550 degrees C under ambient pressure on the laboratory time scale. This is in contrast to the highly exothermic methane fluorination or chlorination reactions, which give kinetic product distributions, and to the endergonic iodination of methane, which yields an equilibrium distribution of iodomethanes. The first phase of reaction between methane and bromine is a relatively rapid consumption of bromine to yield a kinetic methane bromination product distribution characterized by low methane conversion, low methyl bromide selectivity, and higher polybromomethane selectivity. In the second slower phase CHxBr(4-x) reproportionation leads to significantly higher methane conversion and higher methyl bromide selectivity. For methane bromination at 525 degrees C, CH4 conversion and CH3Br selectivity reach 73.5% and 69.5%, respectively, after ample (60 s) time for reproportionation. The high selectivity and simple configuration make this pathway an attractive candidate for scale-up in halogen-mediated methane partial oxidation processes.

  16. Catalytic degradation of brominated flame retardants by copper oxide nanoparticles

    NASA Astrophysics Data System (ADS)

    Dror, I.; Yecheskel, Y.; Berkowitz, B.

    2013-12-01

    Brominated flame retardants (BFRs) have been added to various products like plastic, textile, electronics and synthetic polymers at growing rates. In spite of the clear advantages of reducing fire damages, many of these BFRs may be released to the environment after their beneficial use which may lead to contamination of water resources. In this work we present the catalytic degradation of two brominated flame retardants (BFRs), tribromoneopentyl alcohol (TBNPA) and 2,4 dibromophenol (2,4-DBP) by copper oxide nanoparticles (nCuO) in aqueous solution. The degradation kinetics, the debromination, and the formation of intermediates by nCuO catalysis are compared to Fenton oxidation and to reduction by nano zero-valent iron (nZVI). The two studied BFRs are shown to degrade fully by the nCuO system within hours to days. Shorter reaction times showed differences in reaction pathways and kinetics for the two compounds. The 2,4-DBP showed faster degradation than TBNPA, by nCuO catalysis. Relatively high resistance to degradation was recorded for 2,4-DBP with nZVI, yielding 20% degradation after 24 h, while the TBNPA was degraded by 85% within 12 hours. A catalytic mechanism for radical generation and BFR degradation by nCuO is proposed. It is further suggested that H2O2 plays an essential role in the activation of the catalyst.

  17. Comparative environmental analysis of waste brominated plastic thermal treatments

    SciTech Connect

    Bientinesi, M. Petarca, L.

    2009-03-15

    The aim of this research activity is to investigate the environmental impact of different thermal treatments of waste electric and electronic equipment (WEEE), applying a life cycle assessment methodology. Two scenarios were assessed, which both allow the recovery of bromine: (A) the co-combustion of WEEE and green waste in a municipal solid waste combustion plant, and (B) the staged-gasification of WEEE and combustion of produced syngas in gas turbines. Mass and energy balances on the two scenarios were set and the analysis of the life cycle inventory and the life cycle impact assessment were conducted. Two impact assessment methods (Ecoindicator 99 and Impact 2002+) were slightly modified and then used with both scenarios. The results showed that scenario B (staged-gasification) had a potentially smaller environmental impact than scenario A (co-combustion). In particular, the thermal treatment of staged-gasification was more energy efficient than co-combustion, and therefore scenario B performed better than scenario A, mainly in the impact categories of 'fossil fuels' and 'climate change'. Moreover, the results showed that scenario B allows a higher recovery of bromine than scenario A; however, Br recovery leads to environmental benefits for both the scenarios. Finally the study demonstrates that WEEE thermal treatment for energy and matter recovery is an eco-efficient way to dispose of this kind of waste.

  18. Durability of polymeric materials used in zinc/bromine flow batteries

    NASA Astrophysics Data System (ADS)

    Arnold, C., Jr.

    The lifetimes of zinc/bromine flow batteries may be limited by the durability of components which are fabricated from thermoplastic materials and exposed to the bromine-containing electrolyte. Examples of such components are flowframes and carbon-filled plastic electrodes. In early versions of the zinc/bromine battery, flowframes and electrodes were made from polypropylene and copolymers of propylene and ethylene. In later versions of the zinc/bromine battery, polyvinyl chloride (PVC) was used as the material to fabricate flowframes and polyethylene was used as the material used to fabricate both flowframes and electrodes. We found that carbon-plastic electrodes made from polypropylene or polypropylene rich copolymers were swelled and chemically attacked by the bromine-containing electrolytes. As a result, warpage occurred and the battery failed. On the basis of accelerated aging studies we estimated the lifetimes of the electrode and its polypropylene based component to be 96 and 10 months, respectively. The enhanced stability of the electrode was attributed to the presence of carbon which is known to be an antioxidant for thermoxidation. In accelerated exposure tests, bromine-containing electrolytes were also found to attack and leach out the additives used in PVC flowframes. PVC itself was only slightly degraded by the electrolyte. A commercial fluorocarbon, Tefzel, which contains no additives, was determined to be stable in bromine-containing electrolytes and is recommended as a replacement for PVC. Currently, aging studies on carbon-filled polyethylene electrodes are in progress.

  19. A method to remove intercalates from bromine and iodine intercalated carbon fibers

    NASA Technical Reports Server (NTRS)

    Hung, Ching-Cheh

    1993-01-01

    Upon exposure to room-temperature fluorine, intercalated carbon fibers (containing either bromine alone or iodine and bromine together) become heavier and less stable. For Amoco P-100 graphitized carbon fibers which were intercalated with 18 percent bromine by weight, 1 hr of fluorine exposure results in a large weight increase, but causes only a small decrease in thermal stability. More than l hr of fluorine exposure time results in small additional increases in fiber weight, but significant further decreases in fiber thermal stability. Such phenomena do not occur if the fluorine exposure is at 250 C. These observations suggest the mechanism that at room temperature, fluorine is absorbed quickly by the intercalated fibers and intercalated slowly into the fibers. Most of the original intercalates are replaced by fluorine in the process of fluorine intercalation. Under an inert environment, the bromine intercalated fibers are much more thermally stable. After 800 C vacuum heating for two weeks, the brominated fibers lost about 45 percent of their bromine, and their resistivity increased from 64 omega-cm to a range of 95 to 170 micro omega-cm. This is still much lower than the 300 micro omega-cm value for pristine P-100. For practical purposes, in order to preserve their thermal stability, brominated fibers need to be protected from exposure to fluorine at room temperature, or to any intercalate at a temperature where, upon direct contact to graphite, an intercalation compound can easily be formed.

  20. Characterization of poly(vinyl chloride) aged in a bromine containing electrolyte

    SciTech Connect

    Arnold, C. Jr.; Leo, A.; Tarjani, M.

    1988-01-01

    Poly(vinyl chloride) (PVC) is being considered for use as a flow frame material in a developmental zinc/bromine battery. The choice of PVC was based on its low cost and the ease with which it can be molded into complex parts. The electrolyte used in this battery is a highly corrosive mixture of bromine, zinc bromide, zinc chloride, potassium bromide, potassium chloride and a quaternary amine salt. The quaternary salt serves to reduce the concentration of free bromine in the electrolyte by virtue of its complexing capability. It is well known that aqueous bromine is capable of oxidizing organic compounds. The purpose of the current study was to investigate the effect of a bromine electrolyte on two PVC formulations, PVC-1 and PVC-4. PVC-1 is the designation given to one of B.F. Goodrich's commercial formulations and is the present baseline material for the flow frame. PVC-4 is an experimental B.F. Goodrich formulation that was developed especially for battery applications. We sought answers to such questions as (1) does oxidation and/or bromination take place. (2) does bromine penetrate into the sample and, if so, how far. (3) how are the mechanical and morphological properties affected. and (4) are there differences in stability between PVC-1 and PVC-4. To accelerate the aging processes we aged the PVC samples at an elevated temperature in an electrolyte which did not contain any complexing agent. 5 refs., 6 figs.

  1. Conversion of bromine during thermal decomposition of printed circuit boards at high temperature.

    PubMed

    Jin, Yu-qi; Tao, Lin; Chi, Yong; Yan, Jian-hua

    2011-02-15

    The conversion of bromine during the thermal decomposition of printed circuit boards (PCBs) was investigated at isothermal temperatures ranging from 800°C to 1100°C by using a quartz tube furnace. The influence of temperature, oxygen concentrations (0%, 10% and 21% in the nitrogen-oxygen atmosphere) and content of steam on conversion of bromine was studied. With the increment of temperature, the conversion from organic bromine in the PCBs to inorganic bromine in the gaseous fraction increased from 69.0% to 96.4%. The bromine was mainly evolved as HBr and Br(2) in oxidizing condition and the Br(2)/HBr mass ratio increased at stronger oxidizing atmosphere. The experimental results also indicated that the existence of steam can reduce the formation of Br(2). Furthermore, co-combustion of PCBs with S and CaO, both as addition agents, was investigated, respectively. In the presence of SO(2), Br(2)/HBr mass ratio obviously decreased. Moreover, the utilization of calcium oxide can efficiently promote the conversion of organic bromine to inorganic bromine. According to the experimental results, incinerating PCBs at high temperature can efficiently destroy the organobrominated compounds that are considered to be possible precursors of polybrominated dibenzeo-p-dioxins and dibenzofurans (PBDD/Fs), but the Br(2) and HBr in flue gas should be efficiently controlled.

  2. Bromine Chemistry in the Tropical UTLS during the 2011, 2013 and 2014 ATTREX Experiments

    NASA Astrophysics Data System (ADS)

    Werner, Bodo; Stutz, Jochen; Spolaor, Max; Festa, James; Tsai, Catalina; Colosimo, Fedele; Cheung, Ross; Deutschmann, Tim; Raecke, Rasmus; Scalone, Lisa; Tricoli, Ugo; Pfeilsticker, Klaus; Navarro, Maria; Atlas, Elliot; Chipperfield, Martyn; Hossaini, Ryan

    2015-04-01

    Bromine plays an important role for the chemistry of ozone in the stratosphere and upper troposphere. An accurate quantitative understanding of the sources, sinks, and chemical transformation of bromine species is thus important to understand the bromine budget in the upper troposphere and lower stratosphere (UTLS), which also serves as a gate to the stratosphere. Vertical transport of very short-lived organic bromine precursors and inorganic product gases has been identified as the main source of bromine in the UTLS. However, the contribution of inorganic vs. organic compounds is not well quantified, particularly in the tropical UTLS. A limb scanning Differential Optical Absorption Spectroscopy instrument was deployed onboard NASA's UAV Global Hawk during the NASA Airborne Tropical TRopopause EXperiment (ATTREX) during a series of flights into the eastern and western Pacific tropopause layer (flight altitudes up to 18 km), which is a gateway to the stratosphere. The measurement methodology to retrieve vertical trace gas concentration profiles will be briefly presented. Observations of BrO, NO2 and O3 and of other trace species, in particular of brominated hydrocarbons are compared with simulations of the SLIMCAT CTM and interpreted with respect to photochemistry and the budget of bromine within the tropical tropopause layer (TTL).

  3. A cross-fostering analysis of bromine ion concentration in rats that inhaled 1-bromopropane vapor

    PubMed Central

    Ishidao, Toru; Fueta, Yukiko; Ueno, Susumu; Yoshida, Yasuhiro; Hori, Hajime

    2016-01-01

    Objective: Inhaled 1-bromopropane decomposes easily and releases bromine ion. However, the kinetics and transfer of bromine ion into the next generation have not been clarified. In this work, the kinetics of bromine ion transfer to the next generation was investigated by using cross-fostering analysis and a one-compartment model. Methods: Pregnant Wistar rats were exposed to 700 ppm of 1-bromopropane vapor for 6 h per day during gestation days (GDs) 1-20. After birth, cross-fostering was performed between mother exposure groups and mother control groups, and the pups were subdivided into the following four groups: exposure group, postnatal exposure group, gestation exposure group, and control group. Bromine ion concentrations in the brain were measured temporally. Results: Bromine ion concentrations in mother rats were lower than those in virgin rats, and the concentrations in fetuses were higher than those in mothers on GD20. In the postnatal period, the concentrations in the gestation exposure group decreased with time, and the biological half-life was 3.1 days. Conversely, bromine ion concentration in the postnatal exposure group increased until postnatal day 4 and then decreased. This tendency was also observed in the exposure group. A one-compartment model was applied to analyze the behavior of bromine ion concentration in the brain. By taking into account the increase of body weight and change in the bromine ion uptake rate in pups, the bromine ion concentrations in the brains of the rats could be estimated with acceptable precision. PMID:27108641

  4. Bromine Chemistry in the Tropical UTLS during the 2011, 2013 and 2014 ATTREX Experiments

    NASA Astrophysics Data System (ADS)

    Stutz, J.; Spolaor, M.; Festa, J.; Tsai, J. Y.; Colosimo, S. F.; Cheung, R.; Werner, B.; Deutschmann, T.; Scalone, L.; Raecke, R.; Tricoli, U.; Pfeilsticker, K.; Navarro, M. A.; Atlas, E. L.

    2014-12-01

    Bromine chemistry impacts the levels of ozone in the upper troposphere and the stratosphere. An accurate quantitative understanding of the sources, sinks, and chemical transformation of bromine species is thus important to understand the bromine budget in the upper troposphere and lower stratosphere (UTLS), which also serves as a gate to the stratosphere. Vertical transport of very short-lived organic bromine precursors, such as CHBr3, CH2Br2 and inorganic product gases has been identified as the main source of bromine in the UTLS. However, the contribution of inorganic vs. organic compounds is not well quantified, particularly in the tropical UTLS. A number of chemical processes, including the role of ice particles for the transformation and cycling of inorganic bromine species are also poorly understood. A limb scanning Differential Optical Absorption Spectroscopy Instrument was deployed on-board NASA's unmanned high-altitude Global Hawk aircraft during the 2011, 2013, and 2014 NASA Airborne Tropical TRopopause EXperiment (ATTREX). Flights in the eastern and western Pacific were performed to study, among other topics, the chemistry of bromine and ozone in the subtropical and tropical UTLS. Here we will present observations of BrO, NO2 and other trace species made by this instrument at altitudes between 15 - 20 km. The measurement methodology as well as the procedure to retrieve vertical trace gas concentration profiles will be briefly presented. The combination of those observations with the measurements of organic bromine species from the University of Miami's Whole Air Sampler (GWAS) will be used to determine and interpret the bromine budget in the UTLS.

  5. A comparison of the bromination dynamics of various carbon and graphite fibers

    NASA Technical Reports Server (NTRS)

    Gaier, James R.

    1987-01-01

    The electrical resistance of four grades of pitch-based graphite fibers and three experimental organic vapor-derived fibers was determined in situ during bromination and subsequent exposure to ambient laboratory air. The results show that the least graphitic pitch-based fiber does not brominate significantly, and that bromination and debrominaton reactions proceed much slower for vapor-derived fibers than for pitch-based ones. It is suggested that this decreased reacton rate is primarily due to the differences in graphene plane orientation between the fiber types. The results also imply that the vapor-derived and pitch-based fibers produce true intercalation compounds.

  6. Transuranium isotopes

    SciTech Connect

    Hoffman, D.C.

    1985-12-01

    The needs of the research community for the production of transuranium isotopes, the quantities required, the continuity of production desired, and what a new steady state neutron source would have to provide to satisfy these needs are discussed. Examples of past frontier research which need these isotopes as well as an outline of the proposed Large Einsteinium Activation Program, LEAP, which requires roughly ten times the current production of /sup 254/Es are given. 15 refs., 5 figs., 4 tabs.

  7. Isotopic chirality

    SciTech Connect

    Floss, H.G.

    1994-12-01

    This paper deals with compounds that are chiral-at least in part, due to isotope substitution-and their use in tracing the steric course of enzyme reaction in vitro and in vivo. There are other applications of isotopically chiral compounds (for example, in analyzing the steric course of nonenzymatic reactions and in probing the conformation of biomolecules) that are important but they will not be discussed in this context.

  8. Isotope fractionation in aqua-gas systems: Cl(2)-HCl-Cl(-), Br(2)-HBr-Br(-) and H(2)S-S(2-).

    PubMed

    Czarnacki, Maciej; Hałas, Stanisław

    2012-01-01

    We report calculated values of isotope fractionation factors between chlorine, bromine and sulphide hydrated anions and respective gaseous compounds: hydrogen chloride, hydrogen bromide, molecular chlorine and bromine and hydrogen sulphide. For the calculation of the reduced partition function ratios (β-factors) of hydrated Cl(-), Br(-) and S(2-) anions, we used a model of a cluster composed of the considered ion surrounded by two shells of H(2)O molecules. Only the electrostatic interaction between ion and water molecules treated as electric dipoles was taken into account. The β-factors for the gaseous compounds (HCl, Cl(2), HBr, Br(2) and H(2)S) were calculated from vibrational frequencies reported by Urey and Greiff [Isotopic Exchange Equilibria, J. Am. Chem. Soc. 57, 321 (1935)] and Schauble et al. [Theoretical Estimates Equilibrium Chlorine-Isotope Fractionation, Geochim. Cosmochim. Acta 67, 3267 (2003)]. Low-temperature isotope fractionation between chlorine-hydrated anion and hydrogen chloride attains 1.55-1.68‰ (this work), which is in good agreement with experimental data (1.4-1.8‰) [Z.D. Sharp, J.D. Barnes, T.P. Fischer and M. Halick, An Experimental Determination of Chlorine Isotope Fractionation in Acid Systems and Applications to Volcanic Fumaroles, Geochim. Cosmochim. Acta 74, 264 (2010)]. The predicted isotope fractionations for hydrated bromine and HBr, Br(2) gases are very small, 1000 ln α, do not exceed 0.8‰; thus, the expected variations of bromine isotope composition in aqua-gas systems will require enhanced precision for their detection. In contrast, the sulphur isotope fractionation between H(2)S( gas ) and S(2-) attains 6.0‰ at room temperature and drops nearly linearly to 3.1‰ at 350°C.

  9. Diamagnetic Raman Optical Activity of Chlorine, Bromine, and Iodine Gases.

    PubMed

    Šebestík, Jaroslav; Kapitán, Josef; Pačes, Ondřej; Bouř, Petr

    2016-03-01

    Magnetic Raman optical activity of gases provides unique information about their electric and magnetic properties. Magnetic Raman optical activity has recently been observed in a paramagnetic gas (Angew. Chem. Int. Ed. 2012, 51, 11058; Angew. Chem. 2012, 124, 11220). In diamagnetic molecules, it has been considered too weak to be measurable. However, in chlorine, bromine and iodine vapors, we could detect a significant signal as well. Zeeman splitting of electronic ground-state energy levels cannot rationalize the observed circular intensity difference (CID) values of about 10(-4). These are explicable by participation of paramagnetic excited electronic states. Then a simple model including one electronic excited state provides reasonable spectral intensities. The results suggest that this kind of scattering by diamagnetic molecules is a general event observable under resonance conditions. The phenomenon sheds new light on the role of excited states in the Raman scattering, and may be used to probe molecular geometry and electronic structure.

  10. Enhancement of the carbon electrode capacitance by brominated hydroquinones

    NASA Astrophysics Data System (ADS)

    Gastol, Dominika; Walkowiak, Jedrzej; Fic, Krzysztof; Frackowiak, Elzbieta

    2016-09-01

    This paper presents supercapacitors utilizing new redox-active electrolytes with bromine species. Two sources of Br specimen were investigated, i.e. dibromodihydroxybenzene dissolved in KOH and potassium bromide dissolved in KOH with hydroxybenzene additive. KOH-activated carbon, exhibiting a well-developed porosity, was incorporated as an electrode material. The tested systems revealed a capacitance enhancement explained by Br- and partial BrO3- redox activity. The optimisation of the electrolyte concentration resulted in a capacitance value of 314 F g-1 achieved at 1.1 V voltage range. Good cyclability performance (11% capacitance loss) combined with a high capacitance value (244 F g-1) were obtained for the system operating in 0.2 mol L- 1 C6H4Br2O2 in 2 mol L-1 KOH electrolytic solution.

  11. New Phase Transition of Solid Bromine under High Pressure

    SciTech Connect

    San-Miguel, A.; Libotte, H.; Gaspard, J.-P.; Gauthier, M.; Aquilanti, G.; Pascarelli, S.

    2007-07-06

    Solid bromine has been studied by x-ray absorption spectroscopy experiments up to a maximum pressure of 75 GPa. The data analysis of the extended fine structure reveals that the intramolecular distance first increases, reaching its maximum value at 25{+-}5 GPa. From this value the intramolecular distance abruptly begins to decrease evidencing a nonpreviously observed phase transformation taking place at 25{+-}5 GPa. A maximum variation of 0.08 A ring is observed at 65{+-}5 GPa where again a phase transition occurs. This last transformation could correspond with the recently observed change to an incommensurate modulated phase. We discuss the possible generalization of the observed new phase transition at 25{+-}5 GPa to the case of the other halogens.

  12. Homogeneity of pristine and bromine intercalated graphite fibers

    NASA Technical Reports Server (NTRS)

    Gaier, J. R.; Marino, D.

    1985-01-01

    Wide variations in the resistivity of intercalated graphite fibers and to use these materials for electrical applications, their bulk properties must be established. The homogeneity of the diameter, the resistivity, and the mass density of 50 graphite fibers, before and after bromine intercalation was measured. Upon intercalation the diameter was found to expand by about 5%, the resistivity to decrease by a factor of five, and the density to increase by about 6%. Each individual fiber was found to have uniform diameter and resistivity over macroscopic regions for lengths as long as 7 cm. The ratio of pristine to intercalated resistivity increases as the pristine fiber diameter increases at a rate of 0.16 micron, but decreases with the increasing ratio of intercalated diameter to pristine diameter at a rate of 0.08.

  13. Maternal exposure to brominated flame retardants and infant Apgar scores.

    PubMed

    Terrell, Metrecia L; Hartnett, Kathleen P; Lim, Hyeyeun; Wirth, Julie; Marcus, Michele

    2015-01-01

    Brominated flame retardants (BFRs) and other persistent organic pollutants have been associated with adverse health outcomes in humans and may be particularly toxic to the developing fetus. We investigated the association between in utero polybrominated biphenyl (PBB) and polychlorinated biphenyl (PCB) exposures and infant Apgar scores in a cohort of Michigan residents exposed to PBB through contaminated food after an industrial accident. PBB and PCB concentrations were measured in serum at the time the women were enrolled in the cohort. PBB concentrations were also estimated at the time of conception for each pregnancy using a validated elimination model. Apgar scores, a universal measure of infant health at birth, measured at 1 and 5min, were taken from birth certificates for 613 offspring born to 330 women. Maternal PCB concentrations at enrollment were not associated with below-median Apgar scores in this cohort. However, maternal PBB exposure was associated with a dose-related increase in the odds of a below-median Apgar score at 1min and 5min. Among infants whose mothers had an estimated PBB at conception above the limit of detection of 1 part per billion (ppb) to <2.5ppb, the odds ratio=2.32 (95% CI: 1.22-4.40); for those with PBB⩾2.5ppb the OR=2.62 (95% CI: 1.38-4.96; test for trend p<0.01). Likewise, the odds of a below-median 5min Apgar score increased with higher maternal PBB at conception. It remains critical that future studies examine possible relationships between in utero exposures to brominated compounds and adverse health outcomes.

  14. Maternal exposure to brominated flame retardants and infant Apgar Scores

    PubMed Central

    Terrell, Metrecia L.; Hartnett, Kathleen P.; Lim, Hyeyeun; Wirth, Julie; Marcus, Michele

    2014-01-01

    Brominated flame retardants (BFRs) and other persistent organic pollutants have been associated with adverse health outcomes in humans and may be particularly toxic to the developing fetus. We investigated the association between in utero polybrominated biphenyl (PBB) and polychlorinated biphenyl (PCB) exposures and infant Apgar scores in a cohort of Michigan residents exposed to PBB through contaminated food after an industrial accident. PBB and PCB concentrations were measured in serum at the time the women were enrolled in the cohort. PBB concentrations were also estimated at the time of conception for each pregnancy using a validated elimination model. Apgar scores, a universal measure of infant health at birth, measured at 1 and 5 minutes, were taken from birth certificates for 613 offspring born to 330 women. Maternal PCB concentrations at enrollment were not associated with below–median Apgar scores in this cohort. However, maternal PBB exposure was associated with a dose–related increase in the odds of a below–median Apgar score at 1 minute and 5 minutes. Among infants whose mothers had an estimated PBB at conception above the limit of detection of 1 part per billion, the odds ratio was 2.32 (95 % CI: 1.22– 4.40); for those with PBB ≥ 2.5 ppb the OR=2.62 (95% CI: 1.38-4.96; test for trend p< 0.01). Likewise, the odds of a below–median 5–minute Apgar increased with higher maternal PBB at conception. It remains critical that future studies examine possible relationships between in utero exposures to brominated compounds and adverse health outcomes. PMID:25203650

  15. Interactions between anionic and neutral bromine and rare gas atoms

    SciTech Connect

    Buchachenko, Alexei A.; Grinev, Timur A.; Wright, Timothy G.; Viehland, Larry A.

    2008-02-14

    High-quality, ab initio potential energy functions are obtained for the interaction of bromine atoms and anions with atoms of the six rare gases (Rg) from He to Rn. The potentials of the nonrelativistic {sup 2}{sigma}{sup +} and {sup 2}{pi} electronic states arising from the ground-state Br({sup 2}P)-Rg interactions are computed over a wide range of internuclear separations using a spin-restricted version of the coupled cluster method with single and double excitations and noniterative correction to triple excitations [RCCSD(T)] with an extrapolation to the complete basis set limit, from basis sets of d-aug-cc-pVQZ and d-aug-cc-pV5Z quality. These are compared with potentials derived previously from experimental measurements and ab initio calculations. The same approach is used also to refine the potentials of the Br{sup -}-Rg anions obtained previously [Buchachenko et al., J. Chem. Phys. 125, 064305 (2006)]. Spin-orbit coupling in the neutral species is included both ab initio and via an atomic approximation; deviations between two approaches that are large enough to affect the results significantly are observed only in the Br-Xe and Br-Rn systems. The resulting relativistic potentials are used to compute anion zero electron kinetic energy photoelectron spectra, differential scattering cross sections, and the transport coefficients of trace amounts of both anionic and neutral bromine in the rare gases. Comparison with available experimental data for all systems considered proves a very high precision of the present potentials.

  16. OMI observations of bromine monoxide emissions from salt lakes

    NASA Astrophysics Data System (ADS)

    Suleiman, R. M.; Chance, K.; Liu, X.; Gonzalez Abad, G.; Kurosu, T. P.

    2015-12-01

    In this study, we analyze bromine monoxide (BrO) data from the Ozone Monitoring Instrument (OMI) over various salt lakes. We used OMI data from 2005 to 2014 to investigate BrO signatures from salt lakes. The salt lakes regions we cover include Dead Sea; Salt Lake City, US; Salar de Uyuni, Bolivia; and Namtso, Tibet. Elevated signatures of BrO was found in July and August BrO monthly averages over the Dead Sea. Similar results were found in the BrO monthly averages for August 2006 for the Bolivian Salt Flats. We present a detailed description of the retrieval algorithm for the OMI operational bromine monoxide (BrO) product. The algorithm is based on direct fitting of radiances from 319.0-347.5 nm, within the UV-2 channel of OMI. Radiances are modeled from the solar irradiance, attenuated by contributions from the target gas and interfering gases, rotational Raman scattering, additive and multiplicative closure polynomials and a common mode spectrum. The common mode spectra (one per cross-track position, computed on-line) are the average of several hundred fitting residuals. They include any instrument effects that are unrelated to molecular scattering and absorption cross sections. The BrO retrieval uses albedo- and wavelength-dependent air mass factors (AMFs), which have been pre-computed using climatological BrO profiles. The wavelength-dependent AMF is applied pre-fit to the BrO cross-sections so that vertical column densities are retrieved directly. We validate OMI BrO with ground-based measurements from three stations (Harestua, Lauder, and Barrow) and with chemical transport model simulations. We analyze the global distribution and seasonal variation of BrO and investigate BrO emissions from volcanoes and salt lakes.

  17. Bromine-doped DWNTs: A Molecular Faraday Cage

    NASA Astrophysics Data System (ADS)

    Chen, Gugang; Margine, Roxana; Gupta, Rajeev; Crespi, Vincent; Eklund, Peter; Sumanasekera, Gamini; Bandow, Shunji; Iijima, S.

    2003-03-01

    Raman scattering is used to probe the charge transfer distribution in Bromine-doped double-walled carbon nanotubes (DWNT). Using 1064 nm and 514.5 nm laser excitation we are able to study the charge-transfer sensitive phonons in the inner ( (5,5)) and outer ( (10,10)) tubes of the double-walled pair. The experimental results are compared to our tight binding band structure calculations that include a self-consistent electrostatic term sensitive to the average net charge density on each tube. Upon doping, the nanotube tangential and radial Raman bands from the outer (primary) tubes were observed to shift dramatically to higher frequencies, consistent with a C-C bond contraction driven by the acceptor-doping. The peak intensities of these bands significantly decreased with increasing doping exposure, and they eventually vanished, consistent with a deep depression in the Fermi energy that extinguishes the resonant Raman effect. Interestingly, at the same time, we observed little or no change for the tangential and radial Raman features identified with the inner (secondary) tubes during the bromine doping. Our electronic structure calculations show that the charge distribution between the outer and inner tubes depends on doping level and also, to some extent, on specific tube chirality combinations. In general, in agreement with experiment, the calculations find a very small net charge on the inner tube, consistent with a "Molecular Faraday Effect", e.g., a DWNT of (10, 10)/ (5, 5) configuration that exhibits 0.5 holes/Å total charge transfer, has only 0.04 holes/Å on the inner (secondary) tube.

  18. Preparation and evaluation of composite membranes for zinc/bromine storage batteries

    SciTech Connect

    Arnold, C. Jr.; Assink, R.A.

    1989-01-01

    Low coulombic efficiencies of zinc/bromine redox batteries have been attributed to migration of bromine and negatively charged bromine moieties through the microporous separator used to separate the catholyte from the anolyte. While it has been demonstrated that improvements in coulombic efficiency can be achieved by replacing the microporous separator with a cationic ion exchange membrane, these membranes are expensive and/or not sufficiently conductive to be practicable. We have found that the rate of bromine permeation can be reduced by two orders of magnitude with minimal decreases in conductivity by impregnating commercial microporous polyethylene type separators with sulfonated polysulfone, a cationic polyelectrolyte that was developed in earlier work for other redox storage batteries. 5 refs., 1 fig., 1 tab.

  19. BROMINATED FLAME RETARDANTS: WHAT WE KNOW, AND WHAT WE DON’T

    EPA Science Inventory

    Brominated flame retardants (BFRs) represent a large and diverse class of high volume industrial chemicals which have been developed to provide fire safety. There are many other BFRs which have been used and are under development. Historically, polybrominated biphenyls (PBBs) ...

  20. Oxidation of mercury by bromine in the subtropical Pacific free troposphere

    NASA Astrophysics Data System (ADS)

    Gratz, L. E.; Ambrose, J. L.; Jaffe, D. A.; Shah, V.; Jaeglé, L.; Stutz, J.; Festa, J.; Spolaor, M.; Tsai, C.; Selin, N. E.; Song, S.; Zhou, X.; Weinheimer, A. J.; Knapp, D. J.; Montzka, D. D.; Flocke, F. M.; Campos, T. L.; Apel, E.; Hornbrook, R.; Blake, N. J.; Hall, S.; Tyndall, G. S.; Reeves, M.; Stechman, D.; Stell, M.

    2015-12-01

    Mercury is a global toxin that can be introduced to ecosystems through atmospheric deposition. Mercury oxidation is thought to occur in the free troposphere by bromine radicals, but direct observational evidence for this process is currently unavailable. During the 2013 Nitrogen, Oxidants, Mercury and Aerosol Distributions, Sources and Sinks campaign, we measured enhanced oxidized mercury and bromine monoxide in a free tropospheric air mass over Texas. We use trace gas measurements, air mass back trajectories, and a chemical box model to confirm the origin and chemical history of the sampled air mass. We find the presence of elevated oxidized mercury to be consistent with oxidation of elemental mercury by bromine atoms in this subsiding upper tropospheric air mass within the subtropical Pacific High, where dry atmospheric conditions are conducive to oxidized mercury accumulation. Our results support the role of bromine as the dominant oxidant of mercury in the upper troposphere.

  1. Preparation and evaluation of composite membranes for zinc/bromine storage batteries

    NASA Astrophysics Data System (ADS)

    Arnold, Charles, Jr.; Assink, Roger A.

    Low coulombic efficiencies of zinc/bromine redox batteries were attributed to migration of bromine and negatively charged bromine moieties through the microporous separator used to separate the catholyte from the anolyte. While it was demonstrated that improvements in coulombic efficiency can be achieved by replacing the microporous separator with a cationic ion exchange membrane, these membranes are expensive and/or not sufficiently conductive to be practicable. It was found that the rate of bromine permeation can be reduced by two orders of magnitude with minimal decreases in conductivity by impregnating commercial microporous polyethylene type separators with sulfonated polysulfone, a cationic polyelectrolyte that was developed in earlier work for other redox storage batteries.

  2. ENHANCED FORMATION OF DIOXINS AND FURANS FROM COMBUSTION DEVICES BY ADDITION OF TRACE QUANTITIES OF BROMINE

    EPA Science Inventory

    Past pilot-scale experimental studies have shown a dramatic increase in the formation of certain chlorinated products of incomplete combustion (PICs) caused by the addition of trace amounts of bromine (Br). Emissions of trichloroethylene and tetrachloorethylene, generated as PICs...

  3. Potent anti-inflammatory activity of novel microtubule-modulating brominated noscapine analogs.

    PubMed

    Zughaier, Susu; Karna, Prasanthi; Stephens, David; Aneja, Ritu

    2010-02-11

    Noscapine, a plant-derived, non-toxic, over-the-counter antitussive alkaloid has tubulin-binding properties. Based upon the structural resemblance of noscapine to colchicine, a tubulin-binding anti-inflammatory drug, noscapine and its semi-synthetic brominated analogs were examined for in vitro anti-inflammatory activity. Brominated noscapine analogs were found to inhibit cytokine and chemokine release from macrophage cell lines but did not affect cell viability. Brominated noscapine analogs demonstrated anti-inflammatory properties in both TLR- and non-TLR induced in vitro innate immune pathway inflammation models, mimicking septic and sterile infection respectively. In addition, electron microscopy and immunoblotting data indicated that these analogs induced robust autophagy in human macrophages. This study is the first report to identify brominated noscapines as innate immune pathway anti-inflammatory molecules.

  4. Chemically active components of a bromine-ethanol etchant for semidconductor materials

    SciTech Connect

    Pinyacheva, T.M.; Komisarchik, M.Sh.; Orlov, Yu.F.

    1986-05-10

    The purpose of the present work was to determine the degree of chemical interaction between bromine and ethanol in the etchant, and to investigate the influence of this interaction on etching of cadmium selenide single crystals.

  5. Acute toxicity of chlorine and bromine to fathead minnows and bluegills

    SciTech Connect

    Wilde, E.W.; Soracco, R.J.; Mayack, L.A.; Shealy, R.L.; Broadwell, T.L.

    1983-01-01

    The objective of this study was to compare the relative toxicity of chlorine and BCDMH to three types of fish in a freshwater system used for cooling a nuclear reactor. There are no previous studies comparing BCDMH toxicity with chlorine toxicity. Bromine chloride has been shown to be similar or slightly less toxic than chlorine. The results of this study indicate that chlorine and bromine produce similar residual halogen toxicity to fish. 19 references, 2 tables.

  6. Release of Oxidized Bromine Species From Diatoms: Implication for the Polar Troposphere and Oceanic Polyhalomethane Production

    NASA Astrophysics Data System (ADS)

    Manley, S. L.; Hill, V. L.

    2006-12-01

    Marine and ice diatoms are known producers of polybromomethanes. These trace gases produced from ice algae have been implicated as a source of photochemically active bromine involved in polar surface ozone depletion events. A more dominant source of reactive bromine, however, has been attributed to the reaction on ice particles and in sea spray aerosols of atmospherically derived HOBr with bromide and chloride to produce the dihalogens Br2 and BrCl. We have measured the release of oxidized bromine species (Brox = HOBr, Br2, Br3-1) from polar and temperate diatoms. The highest rates were measured from Porosira glaciales (CCMP 651). Release rates are range from 0.84 to 180 fmoles bromine/hour/cell depending on the species or an approximate maximum of 950 nmoles bromine/mg chl a/hr (P. glaciales). The flux from the diatoms is 0.1 to 7.5 nmoles bromine/cm2 diatom surface/hr. This release occurs from an extracellular bromoperoxidase when a suitable organic substrate is absent. At 0.84 mM bromide (average seawater concentration), the optimal pH for Brox release is 6.5, which is the putative pH of the apoplastic space, and the optimal H2O2 concentration is 250 nM. Based on these results, it is estimated that the amount of bromine released from ice algae as Brox is 10 to 200 times greater than the release of bromine as bromoform from ice algae. The Brox so produced could participate in the abiotic formation of dihalogens in sea ice. Also, Brox released from diatoms may react with specific components of DOC, if present, to indirectly produce polybromomethanes both in sea ice and seawater. The amount of polyhalomethanes produced is not only dependent on the algal species present but also on the composition of DOC.

  7. METHOD OF SEPARATING URANIUM, PLUTONIUM AND FISSION PRODUCTS BY BROMINATION AND DISTILLATION

    DOEpatents

    Jaffey, A.H.; Seaborg, G.T.

    1958-12-23

    The method for separation of plutonium from uranium and radioactive fission products obtained by neutron irradiation of uranlum consists of reacting the lrradiated material with either bromine, hydrogen bromide, alumlnum bromide, or sulfur and bromine at an elevated temperature to form the bromides of all the elements, then recovering substantlally pure plutonium bromide by dlstillatlon in combinatlon with selective condensatlon at prescribed temperature and pressure.

  8. Distribution of bromine in bedded halite in the Green River Formation, southwestern Wyoming

    USGS Publications Warehouse

    Higley, D.K.

    1983-01-01

    The Wilkins Peak Member of the Eocene Green River Formation of southwestern Wyoming contains a series of halite-trona beds deposited in ancestral Lake Gosiute. X-ray fluorescence analysis of 311) salt samples from 10 core holes revealed bromine contents ranging from 11 to 174 ppm. The average concentration, corrected to 100 percent sodium chloride, is approximately 80 ppm. The bromine content of most halite beds increases from the base upward. Variations or 'spikes' in the bromine profile and reversals of the upward increase in bromine are evidenced within several salt beds. Bromine of bed 10 salt zones exhibits a high degree of correlation laterally. No increase in bromine concentration for correlated salt zones was noted from the basin margins to the depositional center in the northeastern part of the study area. A great disparity in salt thickness from the depositional center to the margins suggests stratified lake conditions in which denser, sodium-chloride-saturated bottom brines did not extend to the margins during part of the depositional history of bed 10. Paleosalinity trends of Lake Gosiute determined from the bromine distribution include the following: (1) chemically stratified lake conditions with dense, highly saline bottom waters and a fresher water zone above during much of the depositional history of the halites, (2) gradual evaporation of lake waters in a closed basin with resultant upward increase in salinity for most intervals studied, and (3) absence of lateral lake-bottom salinity gradients or postdepositional salt alteration as determined by the lateral constancy of bromine concentrations for correlated bed 10 halite.

  9. Electrophilic bromination of alkenes: environmental, health and safety aspects of new alternative methods.

    PubMed

    Eissen, Marco; Lenoir, Dieter

    2008-01-01

    More than twenty new alternative methods for bromination of alkenes have been evaluated taking into consideration their resource demands, waste production as well as environmental, health and safety aspects. The cost of bromine and the substances designated to circumvent the application of molecular bromine have also been taken into account. As bromine is only one of several problematic substances being used, its avoidance-by applying bromine supported on solid material or by performing the in situ generation of bromine-does not significantly reduce the technological requirements. On the contrary, the resource demands and amount of waste produced by most new methods are significantly higher compared to the standard methods, especially if the recycling of a carrying agent is not efficient. The method using hydrobromic acid and hydrogen peroxide can be regarded as a competitive alternative to the standard method. The application of certain carrying agents could be interesting, because solvents such as carbon tetrachloride or chloroform used during synthesis could be replaced with less problematic ones during work-up. However, problems associated with these alternatives are not resolved as yet.

  10. Surface Response of Brominated Carbon Media on Laser and Thermal Excitation: Optical and Thermal Analysis Study

    NASA Astrophysics Data System (ADS)

    Multian, Volodymyr V.; Kinzerskyi, Fillip E.; Vakaliuk, Anna V.; Grishchenko, Liudmyla M.; Diyuk, Vitaliy E.; Boldyrieva, Olga Yu.; Kozhanov, Vadim O.; Mischanchuk, Oleksandr V.; Lisnyak, Vladyslav V.; Gayvoronsky, Volodymyr Ya.

    2017-02-01

    The present study is objected to develop an analytical remote optical diagnostics of the functionalized carbons surface. Carbon composites with up to 1 mmol g-1 of irreversibly adsorbed bromine were produced by the room temperature plasma treatment of an activated carbon fabric (ACF) derived from polyacrylonitrile textile. The brominated ACF (BrACF) was studied by elastic optical scattering indicatrix analysis at wavelength 532 nm. The obtained data were interpreted within results of the thermogravimetric analysis, X-ray photoelectron spectroscopy and temperature programmed desorption mass spectrometry. The bromination dramatically reduces the microporosity producing practically non-porous material, while the incorporated into the micropores bromine induces the dielectric and structural impact on surface polarizability and conductivity due to the charging effect. We have found that the elastic optical scattering in proper solid angles in the forward and the backward hemispheres is sensitive to the kind of the bromine bonding, e.g., physical adsorption or chemisorption, and the bromination level, respectively, that can be utilized for the express remote fabrication control of the nanoscale carbons with given interfaces.

  11. Evaluation of bromine substitution factors of DBPs during chlorination and chloramination.

    PubMed

    Hua, Guanghui; Reckhow, David A

    2012-09-01

    Bromine substitution factor (BSF) was used to quantify the effects of disinfectant dose, reaction time, pH, and temperature on the bromine substitution of disinfection byproducts (DBPs) during chlorination and chloramination. The BSF is defined as the ratio of the bromine incorporated into a given class of DBPs to the total concentration of chlorine and bromine in that class. Four classes of DBPs were evaluated: trihalomethanes (THMs), dihaloacetonitriles (DHANs), dihaloacetic acids (DHAAs) and trihaloacetic acids (THAAs). The results showed that the BSFs of the four classes of DBPs generally decreased with increasing reaction time and temperature during chlorination at neutral pH. The BSFs peaked at a low chlorine dose (1 mg/L) and decreased when the chlorine dose further increased. The BSFs of chlorination DBPs at neutral pH are in the order of DHAN > THM & DHAA > THAA. DHAAs formed by chloramines exhibited distinctly different bromine substitution patterns compared to chlorination DHAAs. Brominated DBP formation was generally less affected by the pH change compared to chlorinated DBP formation.

  12. Springtime surface ozone fluctuations at high Arctic latitudes and their possible relationship to atmospheric bromine

    NASA Technical Reports Server (NTRS)

    Oltmans, Samuel J.; Sheridan, Patrick J.; Schnell, Russell C.; Winchester, John W.

    1988-01-01

    At high Arctic stations such as Barrow, Alaska, springtime near-surface ozone amounts fluctuate between the highest and lowest values seen during the course of the year. Episodes when the surface ozone concentration is essentially zero last up to several days during this time of year. In the Arctic Gas and Aerosol Sampling Program (AGASP-I and AGASP-II) in 1983 and 1986, it was found that ozone concentrations often showed a very steep gradient in altitude with very low values near the surface. The cold temperatures, and snow-covered ground make it unlikely that the surface itself would rapidly destroy significant amounts of ozone. The AGASP aircraft measurements that found low ozone concentrations in the lowest layers of the troposphere also found that filterable excess bromine (the amount of bromine in excess of the sea salt component) in samples collected wholly or partially beneath the temperature inversion had higher bromine concentrations than other tropospheric samples. Of the four lowest ozone minimum concentrations, three of them were associated with the highest bromine enrichments. Surface measurements of excess filterable bromine at Barrow show a strong seasonal dependence with values rising dramatically early in March, then declining in May. The concentration of organic bromine gases such as bromoform rise sharply during the winter and then begin to decline after March with winter and early spring values at least three times greater than the summer minimum.

  13. An assessment of transcriptional changes in porcine skin exposed to bromine vapor.

    PubMed

    Rogers, James V; Price, Jennifer A; Wendling, Morgan Q S; Perry, Mark R; Reid, Frances M; Kiser, Robyn C; Graham, John S

    2011-01-01

    Bromine is an industrial chemical that can cause severe cutaneous burns. This study was a preliminary investigation into the effect of cutaneous exposure to bromine vapor using a weanling swine burn model and microarray analysis. Ventral abdominal sites were exposed to a mean calculated bromine vapor concentration of 0.69 g L(-1) for 10 or 20 min. At 48 h postexposure, total RNA from skin samples was isolated, processed, and hybridized to Affymetrix GeneChip Porcine Genome Arrays. Expression analysis revealed that bromine vapor exposure for 10 or 20 min promoted similar transcriptional changes in the number of significantly modulated probe sets. A minimum of 83% of the probe sets was similar for both exposure times. Ingenuity pathways analysis revealed eight common biological functions among the top 10 functions of each experimental group, in which 30 genes were commonly shared among 19 significantly altered signaling pathways. Transcripts encoding heme oxygenase 1, interleukin-1β, interleukin 2 receptor gamma chain, and plasminogen activator inhibitor-1 were identified as common potential therapeutic targets for Phase II/III clinical trial or FDA-approved drugs. The present study is an initial assessment of the transcriptional responses to cutaneous bromine vapor exposure identifying molecular networks and genes that could serve as targets for developing therapeutics for bromine-induced skin injury.

  14. ISOTOPE SEPARATORS

    DOEpatents

    Bacon, C.G.

    1958-08-26

    An improvement is presented in the structure of an isotope separation apparatus and, in particular, is concerned with a magnetically operated shutter associated with a window which is provided for the purpose of enabling the operator to view the processes going on within the interior of the apparatus. The shutier is mounted to close under the force of gravity in the absence of any other force. By closing an electrical circuit to a coil mouated on the shutter the magnetic field of the isotope separating apparatus coacts with the magnetic field of the coil to force the shutter to the open position.

  15. Concentrations and trophic interactions of novel brominated flame retardants, HBCD, and PBDEs in zooplankton and fish from Lake Maggiore (Northern Italy).

    PubMed

    Poma, Giulia; Volta, Pietro; Roscioli, Claudio; Bettinetti, Roberta; Guzzella, Licia

    2014-05-15

    Following the release of the international regulations on PBDEs and HBCD, the aim of this study is to evaluate the concentrations of novel brominated flame retardants (NBFRs), including 1,2-bis(2,4,6-tribromophenoxy) ethane (BTBPE), decabromodiphenyl ethane (DBDPE), hexabromobenzene (HBB), and pentabromoethylbenzene (PBEB), in an Italian subalpine lake located in a populated and industrial area. The study investigated specifically the potential BFR biomagnification in a particular lake's pelagic food web, whose structure and dynamics were evaluated using the Stable Isotope Analysis. The potential BFR biomagnification was investigated by using the trophic-level adjusted BMFs and Trophic Magnification Factors (TMFs), confirming that HBCD and some PBDE congeners are able to biomagnify within food webs. Comparing the calculated values of BMFTL and TMF, a significant positive correlation was observed between the two factors, suggesting that the use of BMFTL to investigate the biomagnification potential of organic chemical compounds might be an appropriate approach when a simple food web is considered.

  16. Bromine partitioning between olivine and melt at OIB source conditions: Indication for volatile recycling

    NASA Astrophysics Data System (ADS)

    Joachim, Bastian; Ruzié, Lorraine; Burgess, Ray; Pawley, Alison; Clay, Patricia L.; Ballentine, Christopher J.

    2016-04-01

    Halogens play a key role in our understanding of volatile transport processes in the Earth's mantle. Their moderate (fluorine) to highly (iodine) incompatible and volatile behavior implies that their distribution is influenced by partial melting, fractionation and degassing processes as well as fluid mobilities. The heavy halogens, particularly bromine and iodine, are far more depleted in the Earth's mantle than expected from their condensation temperature (Palme and O'Neill 2014), so that their very low abundances in basalts and peridotites (ppb-range) make it analytically challenging to investigate their concentrations in Earth's mantle reservoirs and their behavior during transport processes (Pyle and Mather, 2009). We used a new experimental technique, which combines the irradiation technique (Johnson et al. 2000), laser ablation and conventional mass spectrometry. This enables us to present the first experimentally derived bromine partition coefficient between olivine and melt. Partitioning experiments were performed at 1500° C and 2.3 GPa, a P-T condition that is representative for partial melting processes in the OIB source region (Davis et al. 2011). The bromine partition coefficient between olivine and silicate melt at this condition has been determined to DBrol/melt = 4.37•10-4± 1.96•10-4. Results show that bromine is significantly more incompatible than chlorine (˜1.5 orders of magnitude) and fluorine (˜2 orders of magnitude) due to its larger ionic radius. We have used our bromine partitioning data to estimate minimum bromine abundances in EM1 and EM2 source regions. We used minimum bromine bulk rock concentrations determined in an EM1 (Pitcairn: 1066 ppb) and EM2 (Society: 2063 ppb) basalt (Kendrick et al. 2012), together with an estimated minimum melt fraction of 0.01 in OIB source regions (Dasgupta et al. 2007). The almost perfect bromine incompatibility results in minimum bromine abundances in EM1 and EM2 OIB source regions of 11 ppb and 20

  17. An exemplary case of a bromine explosion event linked to cyclone development in the Arctic

    NASA Astrophysics Data System (ADS)

    Blechschmidt, A.-M.; Richter, A.; Burrows, J. P.; Kaleschke, L.; Strong, K.; Theys, N.; Weber, M.; Zhao, X.; Zien, A.

    2016-02-01

    Intense, cyclone-like shaped plumes of tropospheric bromine monoxide (BrO) are regularly observed by GOME-2 on board the MetOp-A satellite over Arctic sea ice in polar spring. These plumes are often transported by high-latitude cyclones, sometimes over several days despite the short atmospheric lifetime of BrO. However, only few studies have focused on the role of polar weather systems in the development, duration and transport of tropospheric BrO plumes during bromine explosion events. The latter are caused by an autocatalytic chemical chain reaction associated with tropospheric ozone depletion and initiated by the release of bromine from cold brine-covered ice or snow to the atmosphere. In this manuscript, a case study investigating a comma-shaped BrO plume which developed over the Beaufort Sea and was observed by GOME-2 for several days is presented. By making combined use of satellite data and numerical models, it is shown that the occurrence of the plume was closely linked to frontal lifting in a polar cyclone and that it most likely resided in the lowest 3 km of the troposphere. In contrast to previous case studies, we demonstrate that the dry conveyor belt, a potentially bromine-rich stratospheric air stream which can complicate interpretation of satellite retrieved tropospheric BrO, is spatially separated from the observed BrO plume. It is concluded that weather conditions associated with the polar cyclone favoured the bromine activation cycle and blowing snow production, which may have acted as a bromine source during the bromine explosion event.

  18. An exemplary case of a bromine explosion event linked to cyclone development in the Arctic

    NASA Astrophysics Data System (ADS)

    Blechschmidt, A.-M.; Richter, A.; Burrows, J. P.; Kaleschke, L.; Strong, K.; Theys, N.; Weber, M.; Zhao, X.; Zien, A.

    2015-09-01

    Intense, cyclone-like shaped plumes of tropospheric bromine monoxide (BrO) are regularly observed by GOME-2 on board the MetOp-A satellite over Arctic sea ice in polar spring. These plumes are often transported by high latitude cyclones, sometimes over several days despite the short atmospheric lifetime of BrO. However, only few studies have focused on the role of polar weather systems in the development, duration and transport of tropospheric BrO plumes during bromine explosion events. The latter are caused by an autocatalytic chemical chain reaction associated with tropospheric ozone depletion and initiated by the release of bromine from cold brine covered ice or snow to the atmosphere. In this manuscript, a case study investigating a comma-shaped BrO plume which developed over the Beaufort Sea and was observed by GOME-2 for several days is presented. By making combined use of satellite data and numerical models, it is shown that the occurrence of the plume was closely linked to frontal lifting in a polar cyclone and that it most likely resided in the lowest 3 km of the troposphere. In contrast to previous case studies, we demonstrate that the dry conveyor belt, a potentially bromine-rich stratospheric air stream which can complicate interpretation of satellite retrieved tropospheric BrO, is spatially separated from the observed BrO plume. It is concluded that weather conditions associated with the polar cyclone favored the bromine activation cycle and blowing snow production, which may have acted as a bromine source during the bromine explosion event.

  19. On the bromination of the dihydroazulene/vinylheptafulvene photo-/thermoswitch

    PubMed Central

    Mazzanti, Virginia; Cacciarini, Martina; Broman, Søren L; Parker, Christian R; Schau-Magnussen, Magnus; Bond, Andrew D

    2012-01-01

    Summary Background: The dihydroazulene (DHA)/vinylheptafulvene (VHF) system (with two cyano groups at C1) functions as a photo-/thermoswitch. Direct ionic bromination of DHA has previously furnished a regioselective route to a 7,8-dibromide, which by elimination was converted to a 7-bromo-substituted DHA. This compound has served as a central building block for functionalization of the DHA by palladium-catalyzed cross-coupling reactions. The current work explores another bromination protocol for achieving the isomeric 3-bromo-DHA and also explores the outcome of additional bromination of this compound as well as of the known 7-bromo-DHA. Results: Radical bromination on two different VHFs by using N-bromosuccinimide/benzoyl peroxide and light, followed by a ring-closure reaction generated the corresponding 3-bromo-DHAs, as confirmed in one case by X-ray crystallography. According to a 1H NMR spectroscopic study, the ring closure of the brominated VHF seemed to occur readily under the reaction conditions. A subsequent bromination–elimination protocol provided a 3,7-dibromo-DHA. In contrast, treating the known 7-bromo-DHA with bromine generated a very labile species that was converted to a new 3,7-dibromoazulene, i.e., the fully unsaturated species. Azulenes were also found to form from brominated compounds when left standing for a long time in the solid state. Kinetics measurements reveal that the 3-bromo substituent enhances the rate of the thermal conversion of the VHF to DHA, which is opposite to the effect exerted by a bromo substituent in the seven-membered ring. Conclusion: Two general procedures for functionalizing the DHA core with a bromo substituent (at positions 3 and 7, respectively) are now available with the DHA as starting material. PMID:23015846

  20. Bromine and bromide content in soils: Analytical approach from total reflection X-ray fluorescence spectrometry.

    PubMed

    Gallardo, Helena; Queralt, Ignasi; Tapias, Josefina; Candela, Lucila; Margui, Eva

    2016-08-01

    Monitoring total bromine and bromide concentrations in soils is significant in many environmental studies. Thus fast analytical methodologies that entail simple sample preparation and low-cost analyses are desired. In the present work, the possibilities and drawbacks of low-power total reflection X-ray fluorescence spectrometry (TXRF) for the determination of total bromine and bromide contents in soils were evaluated. The direct analysis of a solid suspension using 20 mg of fine ground soil (<63 μm) gave a 3.7 mg kg(-1) limit of detection for bromine which, in most cases, was suitable for monitoring total bromine content in soils (Br content range in soils = 5-40 mg kg(-1)). Information about bromide determination in soils is also possible by analyzing the Br content in water soil extracts. In this case, the TXRF analysis can be directly performed by depositing 10 μL of the internal standardized soil extract sample on a quartz glass reflector in a measuring time of 1500 s. The bromide limit of detection by this approach was 10 μg L(-1). Good agreement was obtained between the TXRF results for the total bromine and bromide determinations in soils and those obtained by other popular analytical techniques, e.g. energy dispersive X-ray fluorescence spectrometry (total bromine) and ionic chromatography (bromide). As a study case, the TXRF method was applied to study bromine accumulation in two agricultural soils fumigated with a methyl bromide pesticide and irrigated with regenerated waste water.

  1. Bromine atom production and chain propagation during springtime Arctic ozone depletion events in Barrow, Alaska

    NASA Astrophysics Data System (ADS)

    Thompson, Chelsea R.; Shepson, Paul B.; Liao, Jin; Huey, L. Greg; Cantrell, Chris; Flocke, Frank; Orlando, John

    2017-03-01

    Ozone depletion events (ODEs) in the Arctic are primarily controlled by a bromine radical-catalyzed destruction mechanism that depends on the efficient production and recycling of Br atoms. Numerous laboratory and modeling studies have suggested the importance of heterogeneous recycling of Br through HOBr reaction with bromide on saline surfaces. On the other hand, the gas-phase regeneration of bromine atoms through BrO-BrO radical reactions has been assumed to be an efficient, if not dominant, pathway for Br reformation and thus ozone destruction. Indeed, it has been estimated that the rate of ozone depletion is approximately equal to twice the rate of the BrO self-reaction. Here, we use a zero-dimensional, photochemical model, largely constrained to observations of stable atmospheric species from the 2009 Ocean-Atmosphere-Sea Ice-Snowpack (OASIS) campaign in Barrow, Alaska, to investigate gas-phase bromine radical propagation and recycling mechanisms of bromine atoms for a 7-day period during late March. This work is a continuation of that presented in Thompson et al. (2015) and utilizes the same model construct. Here, we use the gas-phase radical chain length as a metric for objectively quantifying the efficiency of gas-phase recycling of bromine atoms. The gas-phase bromine chain length is determined to be quite small, at < 1.5, and highly dependent on ambient O3 concentrations. Furthermore, we find that Br atom production from photolysis of Br2 and BrCl, which is predominately emitted from snow and/or aerosol surfaces, can account for between 30 and 90 % of total Br atom production. This analysis suggests that condensed-phase production of bromine is at least as important as, and at times greater than, gas-phase recycling for the occurrence of Arctic ODEs. Therefore, the rate of the BrO self-reaction is not a sufficient estimate for the rate of O3 depletion.

  2. Naturally-Occurring Marine Brominated Indoles are Aryl Hydrocarbon Receptor Ligands/Agonists

    PubMed Central

    DeGroot, Danica E.; Franks, Diana G.; Higa, Tatsuo; Tanaka, Junichi; Hahn, Mark E.; Denison, Michael S.

    2015-01-01

    The aryl hydrocarbon receptor (AhR) is a ligand-dependent transcription factor that mediates the toxic and biological effects of structurally diverse chemicals, including the environmental contaminant 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD). As part of a larger effort to identify the full spectrum of chemicals that can bind to and activate the AhR, we have examined the ability of several naturally-occurring marine-derived brominated indoles and brominated (methylthio)indoles (collectively referred to as “brominated indoles”) to bind to the AhR and stimulate AhR-dependent gene expression. Incubation of mouse, rat and guinea pig recombinant cell lines containing a stably transfected AhR-responsive luciferase reporter gene with eight brominated indoles revealed that all compounds stimulated luciferase reporter gene activity, although some species-specific differences were observed. All compounds induced significantly more luciferase activity when incubated with cells for 4 h as compared to 24 h, demonstrating that these compounds are transient activators of the AhR signaling pathway. Three of the brominated indoles induced CYP1A1 mRNA in human HepG2 cells in vitro and Cyp1a mRNA in zebrafish embryos in vivo. The identification of the brominated indoles as direct ligands and activators/agonists of the AhR was confirmed by their ability to compete with [3H]TCDD for binding to the AhR and to stimulate AhR transformation and DNA binding in vitro. Taken together, these marine-derived brominated indoles are members of a new class of naturally-occurring AhR agonists. PMID:26001051

  3. Compensation mechanism of bromine dopants in cadmium telluride single crystals

    DOE PAGES

    Bolotnikov, A. E.; Fochuk, P. M.; Verzhak, Ye. V.; ...

    2015-01-02

    We grew single crystals of cadmium telluride, doped with bromine by the Bridgman method, annealed them under a cadmium overpressure (PCd = 10² - 10⁵ Pa) at 800-1100 K, and investigated their electrical properties at high- and low-temperature. The influence of impurities on the crystals' electrical properties were analyzed using the defect subsystem model; the model includes the possibility of the formation of point intrinsic defects (V²⁻Cd, Cd²⁺i, V²⁺Te, Te²⁻i), and substitutional ones (Br⁰Te, Br⁺Te), as well as complexes of point defects, i.e., (Br⁺Te V²⁻Cd)⁻ and (2Br⁺Te V²⁻Cd)⁰. We established the concentration dependence between free charge carriers and themore » parameters of the annealing process. Here, n(T) and n(PCd) are determined by two dominant defects – Br⁺Te and (2Br⁺Te V²⁻Cd)⁰. Their content varies with the annealing temperature and the vapor pressure of the component; the concentration of other defects is much smaller and almost does not affect the electron density.« less

  4. Catalytic degradation of brominated flame retardants by copper oxide nanoparticles.

    PubMed

    Yecheskel, Yinon; Dror, Ishai; Berkowitz, Brian

    2013-09-01

    The catalytic degradation of two brominated flame retardants (BFRs), tribromoneopentyl alcohol (TBNPA) and 2,4 dibromophenol (2,4-DBP) by copper oxide nanoparticles (nCuO) was investigated. The degradation kinetics, the debromination, and the formation of intermediates by nCuO catalysis were also compared to Fenton oxidation and nano zero-valent iron (nZVI) reduction methods. BFRs have been added to various products like plastic, textile, electronics and synthetic polymers at growing rates. In spite of the clear advantages of reducing fire damages, many of these BFRs may be released to the environment after their beneficial use and become contaminants. The two studied BFRs were fully degraded with sufficient time (hours to days) and oxidation agent (H2O2). Shorter reaction times showed differences in reaction pathway and kinetics. The 2,4-DBP showed faster degradation than TBNPA, by nCuO catalysis. Relatively high resistance to degradation was recorded for 2,4-DBP with nZVI, yielding 20% degradation after 24h, while the TBNPA was degraded by 85% within 12h. Electron Spin Resonance (ESR) measurements show generation of both hydroxyl and superoxide radicals. In addition, inhibition of 2,4-DBP degradation in the presence of spin traps implies a radical degradation mechanism. A catalytic mechanism for radical generation and BFR degradation by nCuO is proposed. It is further suggested that H2O2 plays an essential role in the activation of the catalyst.

  5. Antimicrobial N-brominated hydantoin and uracil grafted polystyrene beads.

    PubMed

    Farah, Shady; Aviv, Oren; Laout, Natalia; Ratner, Stanislav; Domb, Abraham J

    2015-10-28

    Hydantoin-N-halamine derivatives conjugated on polystyrene beads are promising disinfectants with broad antimicrobial activity affected by the gradual release of oxidizing halogen in water. The objective of this work was to identify and test of hydantoin-like molecules possessing urea moiety, which may provide N-haloamines releasing oxidizing halogens when exposed to water at different rates and release profiles for tailored antimicrobial agents. In this work, several hydantoin (five member ring) and for the first time reported, uracil (six member ring) derivatives have been conjugated to polystyrene beads and tested for their lasting antimicrobial activity. Four molecules of each series were conjugated onto polystyrene beads from the reaction of the N-potassium hydantoin or uracil derivatives onto chloromethylated polystyrene beads. A distinct difference in bromine loading capacity and release profiles was found for the different conjugated derivatives. All tested materials exhibit strong antimicrobial activity against Escherichia coli and bacteriophages MS2 of 7 and ~4 log reduction, respectively. These results highlight the antimicrobial potential of halogenated cyclic molecules containing urea groups as water disinfection agents.

  6. Extended analysis of fifth spectrum of bromine: Br V

    NASA Astrophysics Data System (ADS)

    Riyaz, A.; Tauheed, A.; Rahimullah, K.

    2014-11-01

    The fifth spectrum of bromine (Br V) has been studied in the 200-2400 Å wavelength region. The spectrum was photographed on a 3-m normal incidence vacuum spectrograph at the St. Francis Xavier University, Antigonish (Canada) and 6.65-m grazing incidence spectrograph at the Zeeman laboratory (Amsterdam). The light sources used were a triggered spark and sliding spark. The ground configuration of Br V is 4s24p. The excited configurations 4s4p2+4s2(4d+5d+5s+6s+7s+5g+6g)+4s4p(5p+4f)+4p24d in the even parity system and the 4p3+4s2(5p+6p+7p+4f)+4s4p4d+4s4p5s configurations in the odd parity system have been studied. Relativistic Hartree-Fock (HFR) and least squares fitted (LSF) parametric calculations have been used to interpret the observed spectrum. 99 levels of Br V have now been established, 43 being new. Among 394 classified spectral lines, 181 are newly classified. The level 4s27s 2S1/2 is revised. We estimate the accuracy of our measured wavelengths for sharp and unblended lines to be±0.005 Å. The ionization limit is determined as 479,657±200 cm-1 (59.470±0.025 eV).

  7. Compensation mechanism of bromine dopants in cadmium telluride single crystals

    SciTech Connect

    Bolotnikov, A. E.; Fochuk, P. M.; Verzhak, Ye. V.; Parashchuk, T. O.; Freik, D. M.; Panchuk, O. E.; James, R. B.; Gorichok, I. V.

    2015-01-02

    We grew single crystals of cadmium telluride, doped with bromine by the Bridgman method, annealed them under a cadmium overpressure (PCd = 10² - 10⁵ Pa) at 800-1100 K, and investigated their electrical properties at high- and low-temperature. The influence of impurities on the crystals' electrical properties were analyzed using the defect subsystem model; the model includes the possibility of the formation of point intrinsic defects (V²⁻Cd, Cd²⁺i, V²⁺Te, Te²⁻i), and substitutional ones (Br⁰Te, Br⁺Te), as well as complexes of point defects, i.e., (Br⁺Te V²⁻Cd)⁻ and (2Br⁺Te V²⁻Cd)⁰. We established the concentration dependence between free charge carriers and the parameters of the annealing process. Here, n(T) and n(PCd) are determined by two dominant defects – Br⁺Te and (2Br⁺Te V²⁻Cd)⁰. Their content varies with the annealing temperature and the vapor pressure of the component; the concentration of other defects is much smaller and almost does not affect the electron density.

  8. Brominated flame retardants and seafood safety: a review.

    PubMed

    Cruz, Rebeca; Cunha, Sara C; Casal, Susana

    2015-04-01

    Brominated flame retardants (BFRs), frequently applied to industrial and household products to make them less flammable, are highly persistent in the environment and cause multi-organ toxicity in human and wildlife. Based on the review of BFRs presence in seafood published from 2004 to 2014, it is clear that such pollutants are not ideally controlled as the surveys are too restricted, legislation inexistent for some classes, the analytical methodologies diversified, and several factors as food processing and eating habits are generally overlooked. Indeed, while a seafood rich diet presents plenty of nutritional benefits, it can also represent a potential source of these environmental contaminants. Since recent studies have shown that dietary intake constitutes a main route of human exposure to BFRs, it is of major importance to review and enhance these features, since seafood constitutes a chief pathway for human exposure and biomagnification of priority environmental contaminants. In particular, more objective studies focused on the variability factors behind contamination levels, and subsequent human exposure, are necessary to support the necessity for more restricted legislation worldwide.

  9. High-pressure behavior of bromine confined in the one-dimensional channels of zeolite AlPO4-5 single crystals

    NASA Astrophysics Data System (ADS)

    Liu, Zhaodong; Yao, Zhen; Yao, Mingguang; Lv, Jiayin; Chen, Shuanglong; Li, Quanjun; Lv, Hang; Wang, Tianyi; Lu, Shuangchen; Liu, Ran; Liu, Bo; Liu, Jing; Chen, Zhiqiang; Zou, Bo; Cui, Tian; Liu, Bingbing

    2016-09-01

    We present a joint experimental and theoretical study on the high-pressure behavior of bromine confined in the one-dimensional (1D) nanochannels of zeolite AlPO4-5 (AFI) single crystals. Raman scattering experiments indicate that loading bromine into AFI single crystals can lead to the formation of bromine molecular chains inside the nanochannels of the crystals. High-pressure Raman and X-ray diffraction studies demonstrate that high pressure can increase the length of the confined bromine molecular chains and modify the inter- and intramolecular interactions of the molecules. The confined bromine shows a considerably different high-pressure behavior to that of bulk bromine. The pressure-elongated bromine molecular chains can be preserved when the pressure is reduced to ambient pressure. Theoretical simulations explain the experimental results obtained from the Raman spectroscopy and X-ray diffraction studies. Furthermore, we find that the intermolecular distance between confined bromine molecules gradually becomes comparable to the intramolecular bond length in bromine molecules upon compression. This may result in the dissociation of the bromine molecules and the formation of 1D bromine atomic chains at pressures above 24 GPa. Our study suggests that the unique nanoconfinement has a considerable effect on the high-pressure behavior of bromine, and the confined bromine species concomitantly enhance the structural stability of the host AFI single crystals.

  10. Three decades (1983-2010) of contaminant trends in East Greenland polar bears (Ursus maritimus). Part 2: brominated flame retardants.

    PubMed

    Dietz, Rune; Rigét, Frank F; Sonne, Christian; Born, Erik W; Bechshøft, Thea; McKinney, Melissa A; Drimmie, Robert J; Muir, Derek C G; Letcher, Robert J

    2013-09-01

    Brominated flame retardants were determined in adipose tissues from 294 polar bears (Ursus maritimus) sampled in East Greenland in 23 of the 28years between 1983 and 2010. Significant linear increases were found for sum polybrominated diphenyl ether (ΣPBDE), BDE100, BDE153, and hexabromocyclododecane (HBCD). Average increases of 5.0% per year (range: 2.9-7.6%/year) were found for the subadult polar bears. BDE47 and BDE99 concentrations did not show a significant linear trend over time, but rather a significant non-linear trend peaking between 2000 and 2004. The average ΣPBDE concentrations increased 2.3 fold from 25.0ng/g lw (95% C.I.: 15.3-34.7ng/g lw) in 1983-1986 to 58.5ng/g lw (95% C.I.: 43.6-73.4ng/g lw) in 2006-2010. Similar but fewer statistically significant trends were found for adult females and adult males likely due to smaller sample size and years. Analyses of δ(15)N and δ(13)C stable isotopes in hair revealed no clear linear temporal trends in trophic level or carbon source, respectively, and non-linear trends differed among sex and age groups. These increasing concentrations of organobromine contaminants contribute to complex organohalogen mixture, already causing health effects to the East Greenland polar bears.

  11. Regional contamination versus regional dietary differences: understanding geographic variation in brominated and chlorinated contaminant levels in polar bears.

    PubMed

    McKinney, Melissa A; Letcher, Robert J; Aars, Jon; Born, Erik W; Branigan, Marsha; Dietz, Rune; Evans, Thomas J; Gabrielsen, Geir W; Muir, Derek C G; Peacock, Elizabeth; Sonne, Christian

    2011-02-01

    The relative contribution of regional contamination versus dietary differences to geographic variation in polar bear (Ursus maritimus) contaminant levels is unknown. Dietary variation between Alaska, Canada, East Greenland, and Svalbard subpopulations was assessed by muscle nitrogen and carbon stable isotope (δ(15)N, δ(13)C) and adipose fatty acid (FA) signatures relative to their main prey (ringed seals). Western and southern Hudson Bay signatures were characterized by depleted δ(15)N and δ(13)C, lower proportions of C(20) and C(22) monounsaturated FAs and higher proportions of C(18) and longer chain polyunsaturated FAs. East Greenland and Svalbard signatures were reversed relative to Hudson Bay. Alaskan and Canadian Arctic signatures were intermediate. Between-subpopulation dietary differences predominated over interannual, seasonal, sex, or age variation. Among various brominated and chlorinated contaminants, diet signatures significantly explained variation in adipose levels of polybrominated diphenyl ether (PBDE) flame retardants (14-15%) and legacy PCBs (18-21%). However, dietary influence was contaminant class-specific, since only low or nonsignificant proportions of variation in organochlorine pesticide (e.g., chlordane) levels were explained by diet. Hudson Bay diet signatures were associated with lower PCB and PBDE levels, whereas East Greenland and Svalbard signatures were associated with higher levels. Understanding diet/food web factors is important to accurately interpret contaminant trends, particularly in a changing Arctic.

  12. The brominated flame retardants, PBDEs and HBCD, in Canadian human milk samples collected from 1992 to 2005; concentrations and trends.

    PubMed

    Ryan, John Jake; Rawn, Dorothea F K

    2014-09-01

    Human milk samples were collected from individuals residing in various regions across Canada mostly in the years 1992 to 2005. These included five large cities in southern Canada as well as samples from Nunavik in northern Quebec. Comparative samples were also collected from residents of Austin, Texas, USA in 2002 and 2004. More than 300 milk samples were analysed for the brominated flame retardants (BFRs), PBDEs and HBCD, by extraction, purification and quantification using either isotope dilution gas chromatography-mass spectrometry (GC-MS) or liquid chromatography-MS. The Canadian total PBDE values in the years 2002-2005 show median levels of about 20μg/kg on a lipid basis; a value significantly higher than in the 1980s and 1990s. Milk samples from Inuit donors in the northern region of Nunavik were slightly lower in PBDE concentrations than those from populated regions in the south of Quebec. Milk samples from Ontario contained slightly lower amounts of PBDEs in two time periods than those from Texas. HBCD levels in most milk samples were usually less than 1ppb milk lipid and dominated by the α-isomer. This large data set of BFRs in Canadian human milk demonstrates an increase in the last few decades in human exposure to BFRs which now appears to have stabilized.

  13. Isotope-abundance variations and atomic weights of selected elements: 2016 (IUPAC Technical Report)

    USGS Publications Warehouse

    Coplen, Tyler B.; Shrestha, Yesha

    2016-01-01

    There are 63 chemical elements that have two or more isotopes that are used to determine their standard atomic weights. The isotopic abundances and atomic weights of these elements can vary in normal materials due to physical and chemical fractionation processes (not due to radioactive decay). These variations are well known for 12 elements (hydrogen, lithium, boron, carbon, nitrogen, oxygen, magnesium, silicon, sulfur, chlorine, bromine, and thallium), and the standard atomic weight of each of these elements is given by IUPAC as an interval with lower and upper bounds. Graphical plots of selected materials and compounds of each of these elements have been published previously. Herein and at the URL http://dx.doi.org/10.5066/F7GF0RN2, we provide isotopic abundances, isotope-delta values, and atomic weights for each of the upper and lower bounds of these materials and compounds.

  14. Utilization of oxidation reactions for the spectrophotometric determination of captopril using brominating agents

    NASA Astrophysics Data System (ADS)

    El-Didamony, Akram M.; Erfan, Eman A. H.

    2010-03-01

    Three simple, accurate and sensitive methods (A-C) for the spectrophotometric assay of captopril (CPL) in bulk drug, in dosage forms and in the presence of its oxidative degradates have been described. The methods are based on the bromination of captopril with a solution of excess brominating mixture in hydrochloric acid medium. After bromination, the excess brominating mixture is followed by the estimation of surplus bromine by three different reaction schemes. In the first method (A), the determination of the residual bromine is based on its ability to bleach the indigo carmine dye and measuring the absorbance at 610 nm. Method B, involves treating the unreacted bromine with a measured excess of iron(II) and the remaining iron(II) is complexed with 1,10-phenanthroline and the increase in absorbance is measured at 510 nm. In method (C), the surplus bromine is treated with excess of iron(II) and the resulting iron(III) is complexed with thiocyanate and the absorbance is measured at 478 nm. In all the methods, the amount of bromine reacted corresponds to the drug content. The different experimental parameters affecting the development and stability of the color are carefully studied and optimized. Beer's law is valid within a concentration range of 0.4-6.0, 0.4-2.8 and 1.2-4.8 μg mL -1 for methods A, B and C, respectively. The calculated apparent molar absorptivity was found to be 5.16 × 10 4, 9.95 × 10 4 and 1.74 × 10 5 L mol -1 cm -1, for methods A, B and C, respectively. Sandell's sensitivity, correlation coefficients, detection and quantification limits are also reported. No interference was observed from common additives found in pharmaceutical preparations. The proposed methods are successfully applied to the determination of CPL in the tablet formulations with mean recoveries of 99.94-100.11% and the results were statistically compared with those of a reference method by applying Student's t- and F-test.

  15. Sea ice and pollution-modulated changes in Greenland ice core methanesulfonate and bromine

    NASA Astrophysics Data System (ADS)

    Maselli, Olivia J.; Chellman, Nathan J.; Grieman, Mackenzie; Layman, Lawrence; McConnell, Joseph R.; Pasteris, Daniel; Rhodes, Rachael H.; Saltzman, Eric; Sigl, Michael

    2017-01-01

    Reconstruction of past changes in Arctic sea ice extent may be critical for understanding its future evolution. Methanesulfonate (MSA) and bromine concentrations preserved in ice cores have both been proposed as indicators of past sea ice conditions. In this study, two ice cores from central and north-eastern Greenland were analysed at sub-annual resolution for MSA (CH3SO3H) and bromine, covering the time period 1750-2010. We examine correlations between ice core MSA and the HadISST1 ICE sea ice dataset and consult back trajectories to infer the likely source regions. A strong correlation between the low-frequency MSA and bromine records during pre-industrial times indicates that both chemical species are likely linked to processes occurring on or near sea ice in the same source regions. The positive correlation between ice core MSA and bromine persists until the mid-20th century, when the acidity of Greenland ice begins to increase markedly due to increased fossil fuel emissions. After that time, MSA levels decrease as a result of declining sea ice extent but bromine levels increase. We consider several possible explanations and ultimately suggest that increased acidity, specifically nitric acid, of snow on sea ice stimulates the release of reactive Br from sea ice, resulting in increased transport and deposition on the Greenland ice sheet.

  16. The toxicity of brominated and mixed-halogenated dibenzo-p-dioxins and dibenzofurans: An overview

    SciTech Connect

    Weber, L.W.D. |; Greim, H.

    1997-02-21

    Brominated dibenzo-p-dioxins and dibenzofurans can be formed under laboratory conditions by pyrolysis of flame retardants based on polybrominated biphenyls and biphenyl ethers. Their occurrence in the environment, however, is due to combustion processes such as municipal waste incineration and internal combustion engines. As these processes generally take place in the presence of an excess of chlorine, predominantly mixed brominated and chlorinated compounds have been identified so far in environmental samples. Brominated dibenzo-p-dioxins or dibenzofurans bind to the cytosolic Ah receptor about as avidly as their chlorinated congeners and induce hepatic microsomal enzymes with comparable potency. The same holds true for mixed brominated-chlorinated compounds. Gross pathologic symptoms-hypothyroidism, thymic atrophy, wasting of body mass, lethality-also occur at doses that, on a molar concentration basis, are virtually identical to those seen with the chlorinated compounds. Their potency to induce malformations in mice following prenatal exposure is equivalent to that of chlorinated dibenzo-p-dioxins and dibenzofurans. Possible activities as (co)carcinogens and endocrine disrupters have not been evaluated, but are likely to exist. Considering the overall similarity in action of chlorinated and brominated dibenzo-p-dioxins and dibenzofurans, environmental and health assessment should be based on molar body burdens without discrimination for the nature of the halogen. 107 refs., 1 fig., 7 tabs.

  17. A serial dual-electrode detector based on electrogenerated bromine for capillary electrophoresis.

    PubMed

    Du, Fuying; Cao, Shunan; Fung, Ying-Sing

    2014-12-01

    A new serial dual-electrode detector for CE has been designed and fabricated for postcolumn reaction detection based on electrogenerated bromine. A coaxial postcolumn reactor was employed to introduce bromide reagent and facilitate the fabrication of upstream generation electrode by simply sputtering Pt film onto the outer surface of the separation capillary. Bromide introduced could be efficiently converted to bromine at this Pt film electrode and subsequently detected by the downstream Pt microdisk detection electrode. Analytes that react with bromine could be determined by the decrease of bromine reduction current at the downstream electrode resulting from the reaction between analytes and bromine. The effects of serial dual-electrode detector working conditions including electrode potentials, bromide flow rate, and bromide concentration on analytical performance were investigated using glutathione (GSH) and glutathione disulfide (GSSG) as test analytes. Under the optimal conditions, detection limits down to 0.16 μM for GSH and 0.14 μM for GSSG (S/N = 3) as well as linear working ranges of two orders of magnitude for GSH and GSSG were achieved. Furthermore, the separation efficiency obtained by our dual-electrode detector design was greatly improved compared with previous reported design. The developed method has been successfully applied to determine the GSH and GSSG impurity in commercial GSH supplement.

  18. Electrochemical performance and transport properties of a Nafion membrane in a hydrogen-bromine cell environment

    NASA Technical Reports Server (NTRS)

    Baldwin, Richard S.

    1987-01-01

    The overall energy conversion efficiency of a hydrogen-bromine energy storage system is highly dependent upon the characteristics and performance of the ion-exchange membrane utilized as a half-cell separator. The electrochemical performance and transport properties of a duPont Nafion membrane in an aqueous HBr-Br2 environment were investigated. Membrane conductivity data are presented as a function of HBr concentration and temperature for the determination of ohmic voltage losses across the membrane in an operational cell. Diffusion-controlled bromine permeation rates and permeabilities are presented as functions of solution composition and temperature. Relationships between the degree of membrane hydration and the membrane transport characteristics are discussed. The solution chemistry of an operational hydrogen-bromine cell undergoing charge from 45% HBr to 5% HBr is discussed, and, based upon the experimentally observed bromine permeation behavior, predicted cell coulombic losses due to bromine diffusion through the membrane are presented as a function of the cell state-of-charge.

  19. Isotope fractionation

    NASA Astrophysics Data System (ADS)

    Bell, Peter M.

    A rash of new controversy has emerged around the subject of mass-independent isotope fractionation effects, particularly in the case of the oxygen isotopes. To be sure, the controversy has been around for awhile, but it has been given new impetus by the results of a recent study by Mark H. Thiemens and John E. Heidenreich III of the University of California, San Diego (Science, March 4, 1983).Gustav Arrhenius has been trying to convince the planetary science community that chemical effects in isotope fractionation processes could explain observations in meteorites that appear to be outside of the traditionally understood mass-dependent fractionations (G. Arrhenius, J . L. McCrumb, and N. F. Friedman, Astrophys. Space Sci, 65, 297, 1974). Robert Clayton had made the basic observations of oxygen in carbonaceous chondrites that the slope of the δ17 versus δ18 line was 1 instead of the slope of ½ characteristic of terrestrial rocks and lunar samples (Ann. Rev. Nucl. Part. Sci., 28, 501, 1978). The mass-independent effects were ascribed to the apparent contribution of an ancient presolar system component of O16.

  20. Neurotoxicity and risk assessment of brominated and alternative flame retardants.

    PubMed

    Hendriks, Hester S; Westerink, Remco H S

    2015-01-01

    Brominated flame retardants (BFRs) are widely used chemicals that prevent or slow the onset and spreading of fire. Unfortunately, many of these compounds pose serious threats for human health and the environment, indicating an urgent need for safe(r) and less persistent alternative flame retardants (AFRs). As previous research identified the nervous system as a sensitive target organ, the neurotoxicity of past and present flame retardants is reviewed. First, an overview of the neurotoxicity of BFRs in humans and experimental animals is provided, and some common in vitro neurotoxic mechanisms of action are discussed. The combined epidemiological and toxicological studies clearly underline the need for replacing BFRs. Many potentially suitable AFRs are already in use, despite the absence of a full profile of their environmental behavior and toxicological properties. To prioritize the suitability of some selected halogenated and non-halogenated organophosphorous flame retardants and inorganic halogen-free flame retardants, the available neurotoxic data of these AFRs are discussed. The suitability of the AFRs is rank-ordered and combined with human exposure data (serum concentrations, breast milk concentrations and house dust concentrations) and physicochemical properties (useful to predict e.g. bioavailability and persistence in the environment) for a first semi-quantitative risk assessment of the AFRs. As can be concluded from the reviewed data, several BFRs and AFRs share some neurotoxic effects and modes of action. Moreover, the available neurotoxicity data indicate that some AFRs may be suitable substitutes for BFRs. However, proper risk assessment is hampered by an overall scarcity of data, particularly regarding environmental persistence, human exposure levels, and the formation of breakdown products and possible metabolites as well as their toxicity. Until these data gaps in environmental behavioral and toxicological profiles are filled, large scale use of

  1. Bromine-sensitized solar photolysis of CO2.

    PubMed

    Braiman, Mark S; Sailer-Kronlachner, Wilfried; Varjas, Christopher J

    2012-09-06

    Direct photochemical reduction of CO(2) has generally been accomplished by using transition-metal compounds as electron transfer reagents. Here, we show that elemental bromine can function as an alternative photosensitizer. When sunlight is tightly focused on mixtures of CO(2) and Br(2), in the presence of a polar adsorbent such as silica gel, glass wool, alumina, or titania, a metastable red adduct is formed within seconds and concentrates at the point of illumination. Further illumination causes deposition of a stable black film on the polar adsorbent. Mass spectrometry of the cold-trapped red intermediate shows clusters of peaks corresponding to the expected distribution of isotopomers of C(2)O(4)Br(4)(+), as well as of C(2)O(4)Br(3)(+). DFT computations indicate that the lowest-energy species with the formula C(2)O(4)Br(4) is trans-2,4-dibromo-2,4-dihypobromo-1,3-dioxetane. Formation of this molecule from (2CO(2) + 2Br(2)) would require a minimum of 3 visible photons, two of which would hypothetically be used in formation of as-yet undetected CO(2)Br(2) and the third, in a subsequent photodimerization. By elemental analysis, the final amorphous solid product contains a C/Br atomic ratio >12, suggesting that Br(2) is acting photocatalytically. Even with a poorly optimized optical system, the reaction rate has reached as high as 1.6 mg reduced C with 40 s of solar collection using a 30 cm diameter paraboloid reflector. This rate is consistent with the storage of approximately 1% of incident solar energy.

  2. Toxicity of brominated volatile organics to freshwater biota.

    PubMed

    Binet, Monique T; Stauber, Jenny L; Adams, Merrin S; Rhodes, Stuart; Wech, Janine

    2010-09-01

    As part of a larger study investigating the fate and effects of brominated volatile organic compounds (VOCs) in contaminated groundwaters discharging to surface waters, the toxicity of 1,2 dibromoethene (DBE) and 1,1,2-tribromoethene (TriBE) to freshwater aquatic biota was investigated. Their toxicity to bacteria (Microtox(R)), microalgae (Chlorella sp.), cladocerans (Ceriodaphnia dubia), duckweed (Lemna sp.) and midges (Chironomus tepperi) was determined after careful optimization of the test conditions to minimize chemical losses throughout the tests. In addition, concentrations of DBE and TriBE were carefully monitored throughout the bioassays to ensure accurate calculation of toxicity values. 1,2-Dibromoethene showed low toxicity to most species, with concentrations to cause 50% lethality or effect (LC/EC50 values) ranging from 28 to 420 mg/L, 10% lethality or effect (LC/EC10 values) ranging from 18 to 94 mg/L and no-observed-effect concentrations (NOECs) ranging from 22 to 82 mg/L. 1,1,2-Tribromoethene was more toxic than DBE, with LC/EC50 values of 2.4 to 18 mg/L, LC/EC10 values of 0.94 to 11 mg/L and NOECs of 0.29 to 13 mg/L. Using these limited data, together with data from the only other published study on TriBE, moderate-reliability water quality guidelines (WQGs) were estimated from species sensitivity distributions. The proposed guideline trigger values for 95% species protection with 50% confidence were 2 mg/L for DBE and 0.03 mg/L for TriBE. The maximum concentrations of DBE and TriBE in nearby surface waters (3 and 1 microg /L, respectively) were well below these WQGs, so the risk to the freshwater environment receiving contaminated groundwater inflows was considered to be low, with hazard quotients <1 for both VOCs. Environ.

  3. PILOT-SCALE STUDIES ON THE EFFECT OF BROMINE ADDITION ON THE EMISSIONS OF CHLORINATED ORGANIC COMBUSTION BY-PRODUCTS

    EPA Science Inventory

    The paper reports on a study to evaluate organic combustion by-product emissions while feeding varying amounts of bromine (Br) and chlorine (Cl) into a pilot-scale incinerator burning surrogate waste materials. (NOTE: Adding brominated organic compounds to a pilot-scale incinerat...

  4. The NBS Reaction: A Simple Explanation for the Predominance of Allylic Substitution over Olefin Addition by Bromine at Low Concentrations.

    ERIC Educational Resources Information Center

    Wamser, Carl C.; Scott, Lawrence T.

    1985-01-01

    Examines mechanisms related to use of N-bromosuccinimide (NBS) for bromination at an allylic position. Also presents derived rate laws for three possible reactions of molecular bromine with an alkene: (1) free radical substitution; (2) free radical addition; and (3) electrophilic addition. (JN)

  5. Crystallographic fragment-based drug discovery: use of a brominated fragment library targeting HIV protease.

    PubMed

    Tiefenbrunn, Theresa; Forli, Stefano; Happer, Meaghan; Gonzalez, Ana; Tsai, Yingssu; Soltis, Michael; Elder, John H; Olson, Arthur J; Stout, Charles D

    2014-02-01

    A library of 68 brominated fragments was screened against a new crystal form of inhibited HIV-1 protease in order to probe surface sites in soaking experiments. Often, fragments are weak binders with partial occupancy, resulting in weak, difficult-to-fit electron density. The use of a brominated fragment library addresses this challenge, as bromine can be located unequivocally via anomalous scattering. Data collection was carried out in an automated fashion using AutoDrug at SSRL. Novel hits were identified in the known surface sites: 3-bromo-2,6-dimethoxybenzoic acid (Br6) in the flap site and 1-bromo-2-naphthoic acid (Br27) in the exosite, expanding the chemistry of known fragments for development of higher affinity potential allosteric inhibitors. At the same time, mapping the binding sites of a number of weaker binding Br-fragments provides further insight into the nature of these surface pockets.

  6. Crystallographic Fragment Based Drug Discovery: Use of a Brominated Fragment Library Targeting HIV Protease

    PubMed Central

    Tiefenbrunn, Theresa; Forli, Stefano; Happer, Meaghan; Gonzalez, Ana; Tsai, Yingssu; Soltis, Michael; Elder, John H.; Olson, Arthur J.; Stout, C. David

    2013-01-01

    A library of 68 brominated fragments was screened against a new crystal form of inhibited HIV-1 protease in order to probe surface sites in soaking experiments. Often fragments are weak binders with partial occupancy, resulting in weak, difficult-to-fit electron density. The use of a brominated fragment library addresses this challenge, as bromine can be located unequivocally via anomalous scattering. Data collection was carried out in an automated fashion using AutoDrug at SSRL. Novel hits were identified in the known surface sites: 3-bromo-2,6-dimethoxybenzoic acid (Br6) in the flap site, and 1-bromo-2-naphthoic acid (Br27) in the exosite, expanding the chemistry of known fragments for development of higher affinity potential allosteric inhibitors. At the same time, mapping the binding sites of a number of weaker binding Br-fragments provides further insight into the nature of these surface pockets. PMID:23998903

  7. Improved charge carrier lifetime in planar perovskite solar cells by bromine doping

    NASA Astrophysics Data System (ADS)

    Kiermasch, David; Rieder, Philipp; Tvingstedt, Kristofer; Baumann, Andreas; Dyakonov, Vladimir

    2016-12-01

    The charge carrier lifetime is an important parameter in solar cells as it defines, together with the mobility, the diffusion length of the charge carriers, thus directly determining the optimal active layer thickness of a device. Herein, we report on charge carrier lifetime values in bromine doped planar methylammonium lead iodide (MAPbI3) solar cells determined by transient photovoltage. The corresponding charge carrier density has been derived from charge carrier extraction. We found increased lifetime values in solar cells incorporating bromine compared to pure MAPbI3 by a factor of ~2.75 at an illumination intensity corresponding to 1 sun. In the bromine containing solar cells we additionally observe an anomalously high value of extracted charge, which we deduce to originate from mobile ions.

  8. Polyfunctional epoxies - Different molecular weights of brominated polymeric additives as flame retardants in graphite composites

    NASA Technical Reports Server (NTRS)

    Nir, Z.; Gilwee, W. J.; Kourtides, D. A.; Parker, J. A.

    1983-01-01

    The imparting of flame retardancy to graphite-reinforced composites without incurring mechanical property deterioration is investigated for the case of an experimental, trifunctional epoxy resin incorporating brominated polymeric additives (BPAs) of the diglycidyl type. Such mechanical properties as flexural strength and modulus, and short beam shear strength, were measured in dry and in hot/wet conditions, and the glass transition temperature, flammability, and water absorption were measured and compared with nonbromilated systems. Another comparison was made with a tetrafunctional epoxy system. The results obtained are explained in terms of differences in the polymeric backbone length of the bromine carrier polymer. BPAs are found to be a reliable bromine source for fire inhibition in carbon-reinforced composites without compromise of mechanical properties.

  9. The separation of waste printed circuit board by dissolving bromine epoxy resin using organic solvent.

    PubMed

    Zhu, P; Chen, Y; Wang, L Y; Zhou, M; Zhou, J

    2013-02-01

    Separation of waste printed circuit boards (WPCBs) has been a bottleneck in WPCBs resource processing. In this study, the separation of WPCBs was performed using dimethyl sulfoxide (DMSO) as a solvent. Various parameters, which included solid to liquid ratio, temperature, WPCB sizes, and time, were studied to understand the separation of WPCBs by dissolving bromine epoxy resin using DMSO. Experimental results showed that the concentration of dissolving the bromine epoxy resin increased with increasing various parameters. The optimum condition of complete separation of WPCBs was solid to liquid ratio of 1:7 and WPCB sizes of 16 mm(2) at 145°C for 60 min. The used DMSO was vapored under the decompression, which obtained the regenerated DMSO and dissolved bromine epoxy resin. This clean and non-polluting technology offers a new way to separate valuable materials from WPCBs and prevent the environmental pollution of waste printed circuit boards effectively.

  10. Improved charge carrier lifetime in planar perovskite solar cells by bromine doping

    PubMed Central

    Kiermasch, David; Rieder, Philipp; Tvingstedt, Kristofer; Baumann, Andreas; Dyakonov, Vladimir

    2016-01-01

    The charge carrier lifetime is an important parameter in solar cells as it defines, together with the mobility, the diffusion length of the charge carriers, thus directly determining the optimal active layer thickness of a device. Herein, we report on charge carrier lifetime values in bromine doped planar methylammonium lead iodide (MAPbI3) solar cells determined by transient photovoltage. The corresponding charge carrier density has been derived from charge carrier extraction. We found increased lifetime values in solar cells incorporating bromine compared to pure MAPbI3 by a factor of ~2.75 at an illumination intensity corresponding to 1 sun. In the bromine containing solar cells we additionally observe an anomalously high value of extracted charge, which we deduce to originate from mobile ions. PMID:27982095

  11. A comparison of the bromination dynamics of pitch-based and vapor-grown graphite fibers

    NASA Technical Reports Server (NTRS)

    Gaier, J. R.

    1986-01-01

    The electrical resistance of pitch based P-100 fibers and experimental organic vapor grown fibers was recorded in-situ during bromination and subsequent exposure to ambient laboratory air. The results indicate that the bromination and debromination reactions proceed much slower for vapor grown fibers than for pitch based. While this may be due in part to the larger diameter of the vapor grown fibers, the majority of the effect can probably be attributed to the differences in graphene plane orientation between the fiber types. Although the reactions are slower in the vapor grown than in the pitch based fibers, the extent of reaction as measured by the change in electrical resistance is essentially the same, with comparable (or larger) decreases in resistivity. The bromination reaction proceeds with one or more plateaus in the resistance versus time curves, which suggests staging and strengthens the argument that these fibers produce true intercalation compounds.

  12. Improved charge carrier lifetime in planar perovskite solar cells by bromine doping.

    PubMed

    Kiermasch, David; Rieder, Philipp; Tvingstedt, Kristofer; Baumann, Andreas; Dyakonov, Vladimir

    2016-12-16

    The charge carrier lifetime is an important parameter in solar cells as it defines, together with the mobility, the diffusion length of the charge carriers, thus directly determining the optimal active layer thickness of a device. Herein, we report on charge carrier lifetime values in bromine doped planar methylammonium lead iodide (MAPbI3) solar cells determined by transient photovoltage. The corresponding charge carrier density has been derived from charge carrier extraction. We found increased lifetime values in solar cells incorporating bromine compared to pure MAPbI3 by a factor of ~2.75 at an illumination intensity corresponding to 1 sun. In the bromine containing solar cells we additionally observe an anomalously high value of extracted charge, which we deduce to originate from mobile ions.

  13. Complete Reductive Dehalogenation of Brominated Biphenyls by Anaerobic Microorganisms in Sediment

    PubMed Central

    Bedard, Donna L.; Van Dort, Heidi M.

    1998-01-01

    We sought to determine whether microorganisms from the polychlorinated biphenyl (PCB)-contaminated sediment in Woods Pond (Lenox, Mass.) could dehalogenate brominated biphenyls. The PCB dechlorination specificities for the microorganisms in this sediment have been well characterized. This allowed us to compare the dehalogenation specificities for brominated biphenyls and chlorinated biphenyls within a single sediment. Anaerobic sediment microcosms were incubated separately at 25°C with 16 different mono- to tetrabrominated biphenyls (350 μM) and disodium malate (10 mM). Samples were extracted and analyzed by gas chromatography with an electron capture detector and a mass spectrometer detector at various times for up to 54 weeks. All of the tested brominated biphenyls were dehalogenated. For most congeners, including 2,6-dibromobiphenyl (26-BB) and 24-25-BB, the dehalogenation began within 1 to 2 weeks. However, for 246-BB and 2-2-BB, debromination was first observed at 7 and 14 weeks, respectively. Most intermediate products did not persist, but when 2-2-BB was produced as a dehalogenation product, it persisted for at least 15 weeks before it was dehalogenated to 2-BB and then to biphenyl. The dehalogenation specificities for brominated and chlorinated biphenyls were similar: meta and para substituents were generally removed first, and ortho substituents were more recalcitrant. However, the brominated biphenyls were better dehalogenation substrates than the chlorinated biphenyls. All of the tested bromobiphenyls, including those with ortho and unflanked meta and para substituents, were ultimately dehalogenated to biphenyl, whereas their chlorinated counterparts either were not dehalogenation substrates or were only partially dehalogenated. Our data suggest that PCB-dechlorinating microorganisms may be able to dehalogenate brominated biphenyls and may exhibit a relaxed specificity for these substrates. PMID:16349530

  14. Bromide oxidation by ferrate(VI): The formation of active bromine and bromate.

    PubMed

    Jiang, Yanjun; Goodwill, Joseph E; Tobiason, John E; Reckhow, David A

    2016-06-01

    Ferrate (VI) (abbreviated as Fe(VI)) has long been considered as a green oxidant that does not produce any known hazardous byproducts. However, this work shows that Fe(VI) can slowly oxidize bromide forming active bromine (HOBr/OBr(-)) and bromate, and in natural waters total organic bromine (TOBr) can also be detected. Results showed that the highest levels of active bromine and bromate were formed at lower pHs and in the absence of phosphate. Hydrogen peroxide, which forms from the reaction of Fe(VI) and water, plays an essential role in suppressing bromate formation by reducing active bromine back to bromide. Fe(VI) decomposition products (assumed to be particulate phase Fe(III)) can catalyze the decomposition of hydrogen peroxide by Fe(VI). Phosphate had a substantial inhibiting effect on the formation of active bromine, but less so on bromate formation. The presence of the raw water matrix in natural water suppressed bromate formation. For a natural water spiked with 0.1 mg/L of bromide, the bromate and TOBr concentrations after Fe(VI) oxidation were below 3.0 and 15 μg/L, respectively. No consistent trend regarding the effect of pH or buffer ions on TOBr formation was observed due to the competition between Fe(VI), hydrogen peroxide, and natural organic matter (NOM) for reaction with active bromine. Under environmentally relevant conditions, the formation of bromate and TOBr would not be a problem for Fe(VI) application as their concentration levels are quite low.

  15. Chemistry of OClO in the Antarctic stratosphere - Implications for bromine

    NASA Technical Reports Server (NTRS)

    Salawitch, Ross J.; Wofsy, Steven C.; Mcelroy, Michael B.

    1988-01-01

    Previous observations of OClO over the Antarctic obtained in 1986 are used to constrain the stratospheric abundance of bromine. The observed diurnal variation is consistent with the production of OClO via the reaction of ClO with BrO if the branching ratio to the BrCl channel is between 3.5 and 14 percent. Otherwise, an additional source in twilight is indicated. The present results suggest a stratospheric bromine concentration of 16 + or - 4 pptv, a value which is consistent with independent measurements.

  16. Simultaneous electrical resistivity and mass uptake measurements in bromine intercalated fibers

    NASA Technical Reports Server (NTRS)

    Jaworske, D. A.

    1986-01-01

    Changes in mass and electrical resistivity of several types of pitch-based and vapor-grown graphite fibers were monitored during reaction with bromine. The observed threshold pressure dependent reaction suggested that the fibers were intercalated. In the fully brominated compound, the mass was increased by 44 percent and the resistivity was improved by a factor of 17. In the residue compound, the mass was increased by 22 percent and the resistivity was improved by a factor of 5. Fibers possessing different degrees of graphitization had surprisingly similar changes in both mass and resistivity.

  17. X-Ray Spectroscopy of Bromine Compounds and Biomedical Applications

    NASA Astrophysics Data System (ADS)

    Nahar, Sultana N.; Luo, Yi; Le, Linh; Pradhan, A. K.; Chowdhury, E.; Pitzer, R.; Montenegro, M.

    2010-06-01

    In conventional biomedical applications intense and broadband high energy X-rays are used in therapy and diagnostics (theranostics) to ensure sufficient tissue penetration for imaging or treatment. To avoid damages incurred by these, our proposed method, Resonant Theranosticsb,c, aims to find narrow energy regions that corresponds to resonant absorption or emission. We show that such energy bands lie below the K-shell ionization energy, contrary to the research focus on the K-shell ionization energy itself. Targeting these energy bands, Auger processes can be initiated to produce a number of photons and electrons from each atomic/molecular species via photon fluorescence and electron ejections. We will report our study on the bromine compound bromodeoxyuridyne (BUdR), widely used as radiological contrast agent in radiation imaging. The active system is Br^o-Br^+ combination, which can emit or absorb X-rays in the relative narrow energy range of 12 to 13.6 keV, through 1s-np transitions. We will present the oscillator strengths and transition probabilities for various Auger or K-shell 1s-np transitions. We will show that the corresponding cross sections and attenuation coefficients per unit mass, are orders of magnitude higher than the background and that at K-shell ionization energy. Employing these attenuation coefficients in the Monte Carlo simulation program Geant4, we study the intensities of photon and electron emission spectra. Acknowledgment: Partially support: Large Interdisciplinary Grant award of the Ohio State University and NASA (SNN). The computational work was carried out at the Ohio Supercomputer Center, Columbus Ohio. "Resonant X-Ray Enhancement of the Auger Effect in High-Z atoms, molecules, and Nanoparticles: Biomedical Applications", A. K. Pradhan, S. N. Nahar, M. Montenegro, Yan Yu, H. L. Zhang, C. Sur, M. Mrozik, R. M. Pitzer, J. of Phys. Chem. A, 113 (2009), 12356. "Monte Carlo Simulations and Atomic Calculations for Auger Processes in

  18. Fate of PBDEs during food processing: Assessment of formation of mixed chlorinated/brominated diphenyl ethers and brominated dioxins/furans.

    PubMed

    Roszko, Marek; Szymczyk, Krystyna; Jędrzejczak, Renata

    2015-01-01

    The aim of this study was to evaluate effects of food processing on PBDE levels, in particular influence of heat treatment on degradation of PBDEs, including possible formation of chlorinated diphenyl ethers or brominated dioxins/furans as degradation products. It was shown that PBDEs heated in the presence of chlorine (from either organic or inorganic sources) formed mixed chlorinated/brominated diphenyl ethers. However, no PCDEs were formed in the presence of lipids. Lipid medium increased stability of PBDEs exposed to UV irradiation. Profile of congeners formed in result of the debromination reaction was significantly different than profiles observed by some other authors in aliphatic organic solvents. Grilling processes increased concentrations (calculated on the fresh product basis) of the studied compounds by 4-8/22-34% for electric/coal grill, respectively. Depending on the congener and on the applied heat treatment, PBDE mass in pork meat after grilling dropped by 26-53%. No detectable quantities of either brominated dioxins or furans were formed during thermal processing of food containing typical levels of PBDEs.

  19. Canadian Arctic sea ice reconstructed from bromine in the Greenland NEEM ice core.

    PubMed

    Spolaor, Andrea; Vallelonga, Paul; Turetta, Clara; Maffezzoli, Niccolò; Cozzi, Giulio; Gabrieli, Jacopo; Barbante, Carlo; Goto-Azuma, Kumiko; Saiz-Lopez, Alfonso; Cuevas, Carlos A; Dahl-Jensen, Dorthe

    2016-09-21

    Reconstructing the past variability of Arctic sea ice provides an essential context for recent multi-year sea ice decline, although few quantitative reconstructions cover the Holocene period prior to the earliest historical records 1,200 years ago. Photochemical recycling of bromine is observed over first-year, or seasonal, sea ice in so-called "bromine explosions" and we employ a 1-D chemistry transport model to quantify processes of bromine enrichment over first-year sea ice and depositional transport over multi-year sea ice and land ice. We report bromine enrichment in the Northwest Greenland Eemian NEEM ice core since the end of the Eemian interglacial 120,000 years ago, finding the maximum extension of first-year sea ice occurred approximately 9,000 years ago during the Holocene climate optimum, when Greenland temperatures were 2 to 3 °C above present values. First-year sea ice extent was lowest during the glacial stadials suggesting complete coverage of the Arctic Ocean by multi-year sea ice. These findings demonstrate a clear relationship between temperature and first-year sea ice extent in the Arctic and suggest multi-year sea ice will continue to decline as polar amplification drives Arctic temperatures beyond the 2 °C global average warming target of the recent COP21 Paris climate agreement.

  20. Detection and speciation of brominated flame retardants in high-impact polystyrene (HIPS) polymers.

    PubMed

    Holbrook, R D; Davis, J M; Scott, K C K; Szakal, C

    2012-05-01

    Polymeric materials have been suggested as possible environmental sources of persistent organic pollutants such as flame retardants. In situ, micrometre-scale characterization techniques for polymer matrix containing flame retardants may provide some insight into the dominant environmental transfer mechanism(s) of these brominated compounds. In this work, we demonstrate that micro X-ray fluorescence spectroscopy (μXRF), focused ion beam scanning electron microscopy (FIB-SEM) combined with energy dispersive X-ray spectroscopy (EDS), and time-of-flight secondary ion mass spectrometry (ToF-SIMS) are promising techniques for the elemental and chemical identification of brominated fire retardant compounds (such as the deca-congener of polybrominated diphenyl ether, BDE-209) within polymeric materials (e.g. high-impact polystyrene or HIPS). Data from μXRF demonstrated that bromine (Br) inclusions were evenly distributed throughout the HIPS samples, whereas FIB SEM-EDS analysis revealed that small antimony (Sb) and Br inclusions are present, and regionally higher concentrations of Br surround the Sb inclusions (compared to the bulk material). Four prominent mass-to-charge ratio peaks (m/z 485, 487, 489 and 491) that correspond to BDE-209 were identified by ToF-SIMS and can be used to chemically distinguish this molecule on the surface of polymeric materials with respect to other brominated organic molecules. These techniques can be important in any study that investigates the route of entry to the environmental surroundings of BDE-containing materials.

  1. Canadian Arctic sea ice reconstructed from bromine in the Greenland NEEM ice core

    NASA Astrophysics Data System (ADS)

    Spolaor, Andrea; Vallelonga, Paul; Turetta, Clara; Maffezzoli, Niccolò; Cozzi, Giulio; Gabrieli, Jacopo; Barbante, Carlo; Goto-Azuma, Kumiko; Saiz-Lopez, Alfonso; Cuevas, Carlos A.; Dahl-Jensen, Dorthe

    2016-09-01

    Reconstructing the past variability of Arctic sea ice provides an essential context for recent multi-year sea ice decline, although few quantitative reconstructions cover the Holocene period prior to the earliest historical records 1,200 years ago. Photochemical recycling of bromine is observed over first-year, or seasonal, sea ice in so-called “bromine explosions” and we employ a 1-D chemistry transport model to quantify processes of bromine enrichment over first-year sea ice and depositional transport over multi-year sea ice and land ice. We report bromine enrichment in the Northwest Greenland Eemian NEEM ice core since the end of the Eemian interglacial 120,000 years ago, finding the maximum extension of first-year sea ice occurred approximately 9,000 years ago during the Holocene climate optimum, when Greenland temperatures were 2 to 3 °C above present values. First-year sea ice extent was lowest during the glacial stadials suggesting complete coverage of the Arctic Ocean by multi-year sea ice. These findings demonstrate a clear relationship between temperature and first-year sea ice extent in the Arctic and suggest multi-year sea ice will continue to decline as polar amplification drives Arctic temperatures beyond the 2 °C global average warming target of the recent COP21 Paris climate agreement.

  2. BROMINATED FLAME RETARDANTS: WHAT WE KNOW, AND WHAT WE DON�T

    EPA Science Inventory

    Brominated flame retardants (BFRs) represent a large and diverse class of high volume industrial chemicals which have been developed to provide fire safety. There are many other BFRs which have been used and are under development. Historically, polybrominated biphenyls (PBBs) w...

  3. Exposure levels to brominated compounds in seawater swimming pools treated with chlorine.

    PubMed

    Parinet, Julien; Tabaries, Sophie; Coulomb, Bruno; Vassalo, Laurent; Boudenne, Jean-Luc

    2012-03-01

    Despite evidence of formation of brominated compounds in seawater swimming pools treated with chlorine, no data about exposure levels to these compounds have been reported. To address this issue, a survey has been carried out in four establishments (representing 8 pools) fed with seawater and devoted to relaxing and cure treatments (thalassotherapy centres located in Southeast of France). Carcinogenic and mutagenic brominated disinfection byproducts (trihalomethanes -THM- and halogenated acetic acids -HAA-) were quantified at varying levels, statistically related to organic loadings brought by bathers, and not from marine organic matter, and also linked to activities carried out in the pools (watergym vs swimming). Bromoform and dibromoacetic acid, the most abundant THM and HAA detected, were measured at levels up to 18-fold greater than the maximum contaminant levels of 60 and 80 μg/L fixed by US.EPA in drinking waters. The correlations between these disinfection byproducts and other environmental factors such as nitrogen, pH, temperature, free residual chlorine, UV(254), chloride and bromide concentrations, and daily frequentation were examined. Because thalassotherapy and seawater swimming pools (hotels, cruise ships,…) are increasing in use around the world and because carcinogenic and mutagenic brominated byproducts may be produced in chlorinated seawater swimming pools, specific care should be taken to assure cleanliness of users (swimmers and patients taking the waters) and to increase water circulation through media filters to reduce levels of brominated byproducts.

  4. A scalable procedure for light-induced benzylic brominations in continuous flow.

    PubMed

    Cantillo, David; de Frutos, Oscar; Rincon, Juan A; Mateos, Carlos; Kappe, C Oliver

    2014-01-03

    A continuous-flow protocol for the bromination of benzylic compounds with N-bromosuccinimide (NBS) is presented. The radical reactions were activated with a readily available household compact fluorescent lamp (CFL) using a simple flow reactor design based on transparent fluorinated ethylene polymer (FEP) tubing. All of the reactions were carried out using acetonitrile as the solvent, thus avoiding hazardous chlorinated solvents such as CCl4. For each substrate, only 1.05 equiv of NBS was necessary to fully transform the benzylic starting material into the corresponding bromide. The general character of the procedure was demonstrated by brominating a diverse set of 19 substrates containing different functional groups. Good to excellent isolated yields were obtained in all cases. The novel flow protocol can be readily scaled to multigram quantities by operating the reactor for longer time periods (throughput 30 mmol h(-1)), which is not easily possible in batch photochemical reactors. The bromination protocol can also be performed with equal efficiency in a larger flow reactor utilizing a more powerful lamp. For the bromination of phenylacetone as a model, a productivity of 180 mmol h(-1) for the desired bromide was achieved.

  5. Electron stimulated desorption of anions from native and brominated single stranded oligonucleotide trimers.

    PubMed

    Polska, Katarzyna; Rak, Janusz; Bass, Andrew D; Cloutier, Pierre; Sanche, Léon

    2012-02-21

    We measured the low energy electron stimulated desorption (ESD) of anions from thin films of native (TXT) and bromine monosubstituted (TBrXT) oligonucleotide trimers deposited on a gold surface (T = thymidine, X = T, deoxycytidine (C), deoxyadenosine (A) or deoxyguanosine (G), Br = bromine). The desorption of H(-), CH(3)(-)/NH(-), O(-)/NH(2)(-), OH(-), CN(-), and Br(-) was induced by 0 to 20 eV electrons. Dissociative electron attachment, below 12 eV, and dipolar dissociation, above 12 eV, are responsible for the formation of these anions. The comparison of the results obtained for the native and brominated trimers suggests that the main pathways of TBrXT degradation correspond to the release of the hydride and bromide anions. Significantly, the presence of bromine in oligonucleotide trimers blocks the electron-induced degradation of nuclobases as evidenced by a dramatic decrease in CN(-) desorption. An increase in the yields of OH(-) is also observed. The debromination yield of particular oligonucleotides diminishes in the following order: BrdU > BrdA > BrdG > BrdC. Based on these results, 5-bromo-2(')-deoxyuridine appears to be the best radiosensitizer among the studied bromonucleosides.

  6. Reactive airways dysfunction and systemic complaints after mass exposure to bromine.

    PubMed Central

    Woolf, A; Shannon, M

    1999-01-01

    Occasionally children are the victims of mass poisoning from an environmental contaminant that occurs due to an unexpected common point source of exposure. In many cases the contaminant is a widely used chemical generally considered to be safe. In the following case, members of a sports team visiting a community for an athletic event were exposed to chemicals while staying at a local motel. Bromine-based sanitizing agents and other chemicals such as hydrochloric acid, which were used in excess in the motel's swimming pool, may have accounted for symptoms experienced by the boy reported here and at least 16 other adolescents. Samples of pool water contained excess bromine (8.2 microg/mL; ideal pool bromine concentration is 2-4 microg/mL). Symptoms and signs attributable to bromine toxicity included irritative skin rashes; eye, nose, and throat irritation; bronchospasm; reduced exercise tolerance; fatigue; headache; gastrointestinal disturbances; and myalgias. While most of the victims recovered within a few days, the index case and several other adolescents had persistent or recurrent symptoms lasting weeks to months after the exposure. PMID:10339453

  7. Formation of brominated pollutants during the pyrolysis and combustion of tetrabromobisphenol A at different temperatures.

    PubMed

    Ortuño, Nuria; Moltó, Julia; Conesa, Juan A; Font, Rafael

    2014-08-01

    Tetrabromobisphenol A (TBBPA) is the most widely used brominated flame retardant worldwide. A detailed examination of the degradation products emitted during thermal decomposition of TBBPA is presented in the study. Runs were performed in a laboratory furnace at different temperatures (650 and 800 °C) and in different atmospheres (nitrogen and air). More than one hundred semivolatile compounds have been identified by GC/MS, with special interest in brominated ones. Presence of HBr and brominated light hydrocarbons increased with temperature and in the presence of oxygen. Maximum formation of PAHs is observed at pyrolytic condition at the higher temperature. High levels of 2,4-, 2,6- and 2,4,6- bromophenols were found. The levels of polybrominated dibenzo-p-dioxins and furans have been detected in the ppm range. The most abundant isomers are 2,4,6,8-TeBDF in pyrolysis and 1,2,3,7,8-PeBDF in combustion. These results should be considered in the assessment of thermal treatment of materials containing brominated flame retardants.

  8. 40 CFR 721.10670 - Bromine, manufacture of, by-products from, distillation residues.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... from, distillation residues. 721.10670 Section 721.10670 Protection of Environment ENVIRONMENTAL..., distillation residues. (a) Chemical substance and significant new uses subject to reporting. (1) The chemical substance identified generically as bromine, manufacture of, by-products from, distillation residues (PMN...

  9. 40 CFR 721.10670 - Bromine, manufacture of, by-products from, distillation residues.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... from, distillation residues. 721.10670 Section 721.10670 Protection of Environment ENVIRONMENTAL..., distillation residues. (a) Chemical substance and significant new uses subject to reporting. (1) The chemical substance identified generically as bromine, manufacture of, by-products from, distillation residues (PMN...

  10. Asymmetric bromine-lithium exchange: application toward the synthesis of natural product.

    PubMed

    Graff, Julien; Debande, Thibaut; Praz, Jézabel; Guénée, Laure; Alexakis, Alexandre

    2013-08-16

    Asymmetric bromine-lithium exchange has been successfully employed to synthesize bicoumarin chiral building blocks of (+)-isokotanin A and (-)-kotanin in good yields and with an excellent level of enantioselectivity. This is the first reported example of formal syntheses, using this direct methodology, leading to the single (M)-atropoisomer of (+)-isokotanin A and (-)-kotanin building blocks, without any resolution step.

  11. Bromine radical-mediated sequential radical rearrangement and addition reaction of alkylidenecyclopropanes.

    PubMed

    Kippo, Takashi; Hamaoka, Kanako; Ryu, Ilhyong

    2013-01-16

    Bromine radical-mediated cyclopropylcarbinyl-homoallyl rearrangement of alkylidenecyclopropanes was effectively accomplished by C-C bond formation with allylic bromides, which led to the syntheses of 2-bromo-1,6-dienes. A three-component coupling reaction comprising alkylidenecyclopropanes, allylic bromides, and carbon monoxide also proceeded well to give 2-bromo-1,7-dien-5-ones in good yield.

  12. Thermoelectric properties of bromine filled CoSb3 skutterudite

    SciTech Connect

    Ortiz, Brenden R.; Crawford, Caitlin M.; McKinney, Robert W.; Parilla, Philip A.; Toberer, Eric S.

    2016-01-01

    Historically, the improved thermoelectric performance of skutterudite compounds has largely been driven by the incorporation of electropositive donors on interstitial sites. These 'rattlers' serve to optimize both electronic and thermal properties by tuning the carrier concentration and scattering phonons. In this work, we show that interstitial bromine can be incorporated into CoSb3 and assess the impact on electronic and thermal transport. In contrast to prior high pressure syntheses with iodine, interstitial bromine incorporation is achieved at ambient pressure. Transport properties are stable up to at least 375 degrees C. Bromine serves as an electronegative acceptor and can induce degenerate (>5 x 1019 cm-3) hole densities. In contrast to other p-type skutterudite compositions, bromine preserves the intrinsically high hole mobility of CoSb3 while significantly reducing the lattice thermal conductivity. The development of a stable p-type dopant for the interstitial filler site enables the development of skutterudites with both donor and acceptor interstitials to maximize phonon scattering while maintaining the high mobility of CoSb3.

  13. Electron stimulated desorption of anions from native and brominated single stranded oligonucleotide trimers

    SciTech Connect

    Polska, Katarzyna; Rak, Janusz; Bass, Andrew D.; Cloutier, Pierre; Sanche, Leon

    2012-02-21

    We measured the low energy electron stimulated desorption (ESD) of anions from thin films of native (TXT) and bromine monosubstituted (TBrXT) oligonucleotide trimers deposited on a gold surface (T = thymidine, X = T, deoxycytidine (C), deoxyadenosine (A) or deoxyguanosine (G), Br = bromine). The desorption of H{sup -}, CH{sub 3}{sup -}/NH{sup -}, O{sup -}/NH{sub 2}{sup -}, OH{sup -}, CN{sup -}, and Br{sup -} was induced by 0 to 20 eV electrons. Dissociative electron attachment, below 12 eV, and dipolar dissociation, above 12 eV, are responsible for the formation of these anions. The comparison of the results obtained for the native and brominated trimers suggests that the main pathways of TBrXT degradation correspond to the release of the hydride and bromide anions. Significantly, the presence of bromine in oligonucleotide trimers blocks the electron-induced degradation of nuclobases as evidenced by a dramatic decrease in CN{sup -} desorption. An increase in the yields of OH{sup -} is also observed. The debromination yield of particular oligonucleotides diminishes in the following order: BrdU > BrdA > BrdG > BrdC. Based on these results, 5-bromo-2{sup '}-deoxyuridine appears to be the best radiosensitizer among the studied bromonucleosides.

  14. Final Report, "Laboratory Studies of the Role of Sea Salt Bromine in Determining Tropospheric Ozone"

    SciTech Connect

    B. J. Finlayson-Pitts

    2005-06-20

    This document is a final report for the project DE-FG03-98ER62578, "Laboratory Studies of the Role of Sea Salt Bromine in Determining Tropospheric Ozone". It includes a technical summary, collaborations, educational contributions and the peer-reviewed scientific publications that have resulted from this research.

  15. Bromine incorporation factors for trihalomethane formation for the Mississippi, Missouri, and Ohio Rivers

    USGS Publications Warehouse

    Rathbun, R.E.

    1996-01-01

    The bromine incorporation factor describes the distribution of the four trihalomethane compounds in the mixture formed when a natural water is chlorinated. This factor was determined for the Mississippi, Missouri, and Ohio Rivers by chlorinating water samples at three levels each of pH and free chlorine concentration. Samples were collected during the summer, fall, and spring seasons of the year at 12 sites on the Mississippi River from Minneapolis, MN, to New Orleans, LA, and on the Missouri and Ohio Rivers 1.6 kilometers upstream from their confluences with the Mississippi. The bromine incorporation factor increased as the bromide concentration increased, and decreased as the pH, initial free-chlorine and dissolved organic-carbon concentrations increased. Variation of the bromine incorporation factor with distance along the Mississippi River approximately paralleled the variation of the bromide concentration with distance along the river, with the Missouri River samples having the highest bromine incorporation factors for all combinations of pH and free-chlorine concentration.

  16. Canadian Arctic sea ice reconstructed from bromine in the Greenland NEEM ice core

    PubMed Central

    Spolaor, Andrea; Vallelonga, Paul; Turetta, Clara; Maffezzoli, Niccolò; Cozzi, Giulio; Gabrieli, Jacopo; Barbante, Carlo; Goto-Azuma, Kumiko; Saiz-Lopez, Alfonso; Cuevas, Carlos A.; Dahl-Jensen, Dorthe

    2016-01-01

    Reconstructing the past variability of Arctic sea ice provides an essential context for recent multi-year sea ice decline, although few quantitative reconstructions cover the Holocene period prior to the earliest historical records 1,200 years ago. Photochemical recycling of bromine is observed over first-year, or seasonal, sea ice in so-called “bromine explosions” and we employ a 1-D chemistry transport model to quantify processes of bromine enrichment over first-year sea ice and depositional transport over multi-year sea ice and land ice. We report bromine enrichment in the Northwest Greenland Eemian NEEM ice core since the end of the Eemian interglacial 120,000 years ago, finding the maximum extension of first-year sea ice occurred approximately 9,000 years ago during the Holocene climate optimum, when Greenland temperatures were 2 to 3 °C above present values. First-year sea ice extent was lowest during the glacial stadials suggesting complete coverage of the Arctic Ocean by multi-year sea ice. These findings demonstrate a clear relationship between temperature and first-year sea ice extent in the Arctic and suggest multi-year sea ice will continue to decline as polar amplification drives Arctic temperatures beyond the 2 °C global average warming target of the recent COP21 Paris climate agreement. PMID:27650478

  17. Using the parallelogram approach to estimate human percutaneous bioavailability for novel & legacy brominated flame retardants

    EPA Science Inventory

    (This is an extended abstract. The following text was taken from the Discussion and Conclusion section.) Humans are frequently exposed to brominated flame retardants (BFRs), especially via dermal contact with contaminated dust. Human and rat skin data were integrated using a pa...

  18. Construction and performance of a high voltage zinc bromine battery in an electric vehicle

    SciTech Connect

    Swan, D.H.; Dickinson, B.; Arikara, M.; Prabhu, M.

    1995-07-01

    This paper describes the design, construction, testing and installation of a 391 volt, 35 kWh zinc bromine battery in an electric vehicle. This research project, was referred to as the Endura Project and it resulted in the construction of the highest voltage zinc bromine battery ever to be used in an electric vehicle. The zinc bromine battery is a high energy density battery that utilizes low cost materials (predominantly polyethylene plastic). It has a relatively high energy density (60 to 70 Wh/kg of battery weight) and is modular in its construction. It utilizes a water cooling loop and normally operates between 32 and 45 C. The Endura project constructed a state of the art zinc bromine battery, used an advanced charging system, and an advanced AC propulsion system. These components were integrated in a Geo Prizm and used to compete in the APS Electric 500 in Phoenix, AZ (3rd place, 3/94), the World Clean Air Rally in LA (1st Place, 4/94) and the 1994 American Tour de Sol (2nd Place 5/94).

  19. Kinetics of aerobic cometabolic biodegradation of chlorinated and brominated aliphatic hydrocarbons: A review.

    PubMed

    Jesus, João; Frascari, Dario; Pozdniakova, Tatiana; Danko, Anthony S

    2016-05-15

    This review analyses kinetic studies of aerobic cometabolism (AC) of halogenated aliphatic hydrocarbons (HAHs) from 2001-2015 in order to (i) compare the different kinetic models proposed, (ii) analyse the estimated model parameters with a focus on novel HAHs and the identification of general trends, and (iii) identify further research needs. The results of this analysis show that aerobic cometabolism can degrade a wide range of HAHs, including HAHs that were not previously tested such as chlorinated propanes, highly chlorinated ethanes and brominated methanes and ethanes. The degree of chlorine mineralization was very high for the chlorinated HAHs. Bromine mineralization was not determined for studies with brominated aliphatics. The examined research period led to the identification of novel growth substrates of potentially high interest. Decreasing performance of aerobic cometabolism were found with increasing chlorination, indicating the high potential of aerobic cometabolism in the presence of medium- and low-halogenated HAHs. Further research is needed for the AC of brominated aliphatic hydrocarbons, the potential for biofilm aerobic cometabolism processes, HAH-HAH mutual inhibition and the identification of the enzymes responsible for each aerobic cometabolism process. Lastly, some indications for a possible standardization of future kinetic studies of HAH aerobic cometabolism are provided.

  20. ACUTE POSTNATAL EXPOSURE TO BROMINATED DIPHENYLETHER 47 DELAYS NEUROMOTOR ONTOGENY AND ALTERS MOTOR ACTIVITY IN MICE

    EPA Science Inventory

    Polybrominated diphenyl ethers (PBDEs) are widely used commercial flame retardants that are accumulating in the environment. 2,2’,4,4’-Brominated diphenyl ether (BDE 47) is a very stable congener of this group and has been shown to accumulate in humans. PBDEs may interfere with...

  1. 40 CFR 721.10416 - Brominated polyphenyl ether (generic) (P-11-264).

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... (CONTINUED) TOXIC SUBSTANCES CONTROL ACT SIGNIFICANT NEW USES OF CHEMICAL SUBSTANCES Significant New Uses for Specific Chemical Substances § 721.10416 Brominated polyphenyl ether (generic) (P-11-264). (a) Chemical substance and significant new uses subject to reporting. (1) The chemical substance identified...

  2. Unintentional production of persistent chlorinated and brominated organic pollutants during iron ore sintering processes.

    PubMed

    Li, Sumei; Liu, Guorui; Zheng, Minghui; Liu, Wenbin; Li, Jinhui; Wang, Mei; Li, Changliang; Chen, Yuan

    2017-06-05

    Iron ore sintering (SNT) processes are major sources of unintentionally produced chlorinated persistent organic pollutants (POPs), including polychlorinated dibenzo-p-dioxins/dibenzofurans (PCDD/Fs), polychlorinated biphenyls (PCBs), and polychlorinated naphthalenes (PCNs). However, few studies of emissions of brominated POPs, such as polybrominated dibenzo-p-dioxins/dibenzofurans (PBDD/Fs) and polybrominated diphenyl ethers (PBDEs), during SNT have been performed. Stack gas and fly ash samples from six typical SNT plants in China were collected and analyzed to determine the concentrations and profiles of PCDD/Fs, PCBs, PCNs, PBDD/Fs, and PBDEs, as well as any correlations among these compounds. The PCDD/F, PCB, PCN, PBDD/F, and PBDE emission factors were 2.47, 0.61, 552, 0.32, and 107μgt(-1), respectively (109, 4.07, 10.4, 4.41 and 0.02ng toxic equivalents t(-1), respectively). PCBs were the most abundant compounds by mass, while PCNs were the next most abundant, contributing 51% and 42% to the total POP concentration, respectively. However, PCDD/Fs were the dominant contributors to the chlorinated and brominated POP toxic equivalent concentrations, contributing 89% to the total toxic equivalent concentration. The PCDD/F and other chlorinated and brominated POP concentrations were positively correlated, indicating that chlorinated and brominated POP emissions could be synergistically decreased using the best available technologies/best environmental practices already developed for PCDD/Fs.

  3. Room-Temperature Fluorine-Induced Decrease in the Stability of Bromine and Iodine Intercalated Carbon Fibers

    NASA Technical Reports Server (NTRS)

    Hung, Ching-Cheh

    1995-01-01

    Upon exposure to room-temperature fluorine, intercalated carbon fibers (containing either bromine alone or iodine and bromine together) become heavier and less stable. For Amoco P-100 graphitized carbon fibers, which were intercalated with 18 wt percent bromine, 1 hour of fluorine exposure resulted in a large weight increase but caused only a small decrease in thermal stability. An additional 89 hours of fluorine exposure time resulted in small additional increases in fiber weight, but significant further decreases in fiber thermal stability. Such phenomena of weight increase and stability decrease do not occur if the intercalated fibers are exposed to 250 C fluorine. These observations suggest that, at room temperature, fluorine is absorbed quickly by the intercalated fibers and is intercalated slowly into the fibers. Most of the original intercalates are replaced by fluorine in the process of fluorine intercalation. In an inert environment, the bromine intercalated fibers are much more thermally stable. After 800 C vacuum heating for 2 weeks, the brominated fibers lost about 45% of their bromine, and their resistivity increased from 64 mu(Omega)-cm to a range of 95-170 mu(Omega)-cm. This is still much lower than the value of 300 mu(Omega)-cm for pristine P-100. For practical purposes, to preserve their thermal stability, brominated fibers need to be protected from exposure to fluorine at room temperature or to any intercalate at a temperature where, upon direct contact with graphite, an intercalation compound can easily be formed.

  4. Bromine release from blowing snow and its impact on tropospheric chemistry

    NASA Astrophysics Data System (ADS)

    Griffiths, Paul; Yang, Xin; Abraham, N. Luke; Archibald, Alexander; Pyle, John

    2016-04-01

    In the last two decades, significant depletion of boundary layer ozone (ozone depletion events, ODEs) has been observed in both Arctic and Antarctic spring. ODEs are attributed to catalytic destruction by bromine radicals (Br plus BrO), especially during bromine explosion events (BEs), when high concentrations of BrO periodically occur. The source of bromine and the mechanism that sustains the high BrO levels are still the subject of study. Recent work by Pratt et al. (2013) posits Br2 production within saline snow and sea ice which leads to sudden ODEs. Previously, Yang et al. (2008) suggested snow could provide a source of (depleted) sea-salt aerosol if wicked from the surface of ice. They suggest that rapid depletion of bromide from the aerosol will constitute a source of photochemical Bry. Given the large sea ice extent in polar regions, this may constitute a significant source of sea salt and bromine in the polar lower atmosphere. While bromine release from blowing snow is perhaps less likely to trigger sudden ODEs, it may make a contribution to regional scale processes affecting ozone levels. Currently, the model parameterisations of Yang et al. assumes that rapid release of bromine occurs from fresh snow on sea ice during periods of strong wind. The parameterisation depends on an assumed sea-salt aerosol distribution generated via sublimation of the snow above the boundary layer, as well as taking into account the salinity of the snow. In this work, we draw on recent measurements by scientists from the British Antarctic Survey during a cruise aboard the Polarstern in the southern oceans. This has provided an extensive set of measurements of the chemical and physical characteristics of blowing snow over sea ice, and of the aerosol associated with it. Based on the observations, we have developed an improved parameterisation of the release of bromine from blowing snow. The paper presents results from the simulation performed using the United Kingdom Chemistry

  5. Method for separating isotopes

    DOEpatents

    Jepson, B.E.

    1975-10-21

    Isotopes are separated by contacting a feed solution containing the isotopes with a cyclic polyether wherein a complex of one isotope is formed with the cyclic polyether, the cyclic polyether complex is extracted from the feed solution, and the isotope is thereafter separated from the cyclic polyether.

  6. Separation of selected stable isotopes by liquid-phase thermal diffusion and by chemical exchange

    NASA Astrophysics Data System (ADS)

    Rutherford, W. M.; Jepson, B. E.; Michaels, E. D.

    Useful applications of enriched stable nuclides are unduly restricted by high cost and limited availability. Recent research on liquid phase thermal diffusion (LTD) has resulted in practical processes for separating S34, CL35, and CL37 in significant quantities (100 to 500 g/yr) at costs much lower than those associated with the electromagnetic (Calutron) process. The separation of the isotopes of bromine by LTD is now in progress and BR79 is being produced in relatively simple equivalent at a rate on the order of 0.5 g/day. The results of recent measurements show that the isotopes of Zn can be separated by LTD of zinc alkyls. The isotopes of calcium can be separated by LTD and by chemical exchange. The LTD process is based on the use of aqueous Ca(NO3)2 as a working fluid.

  7. A case study of a transported bromine explosion event in the Canadian high arctic

    NASA Astrophysics Data System (ADS)

    Zhao, X.; Strong, K.; Adams, C.; Schofield, R.; Yang, X.; Richter, A.; Friess, U.; Blechschmidt, A.-M.; Koo, J.-H.

    2016-01-01

    Ozone depletion events in the polar troposphere have been linked to extremely high concentrations of bromine, known as bromine explosion events (BEE). However, the optimum meteorological conditions for the occurrence of these events remain uncertain. On 4-5 April 2011, a combination of both blowing snow and a stable shallow boundary layer was observed during a BEE at Eureka, Canada (86.4°W, 80.1°N). Measurements made by a Multi-Axis Differential Optical Absorption Spectroscopy spectrometer were used to retrieve BrO profiles and partial columns. During this event, the near-surface BrO volume mixing ratio increased to ~20 parts per trillion by volume, while ozone was depleted to ~1 ppbv from the surface to 700 m. Back trajectories and Global Ozone Monitoring Experiment-2 satellite tropospheric BrO columns confirmed that this event originated from a bromine explosion over the Beaufort Sea. From 30 to 31 March, meteorological data showed high wind speeds (24 m/s) and elevated boundary layer heights (~800 m) over the Beaufort Sea. Long-distance transportation (~1800 km over 5 days) to Eureka indicated strong recycling of BrO within the bromine plume. This event was generally captured by a global chemistry-climate model when a sea-salt bromine source from blowing snow was included. A model sensitivity study indicated that the surface BrO at Eureka was controlled by both local photochemistry and boundary layer dynamics. Comparison of the model results with both ground-based and satellite measurements confirmed that the BEE observed at Eureka was triggered by transport of enhanced BrO from the Beaufort Sea followed by local production/recycling under stable atmospheric shallow boundary layer conditions.

  8. Determination of iodine and bromine compounds in foodstuffs by CE-inductively coupled plasma MS.

    PubMed

    Chen, Jing-Huan; Wang, Kai-en; Jiang, Shiuh-Jen

    2007-11-01

    A CE-inductively coupled plasma mass spectrometric (CE-ICP-MS) method for iodine and bromine speciation analysis is described. Samples containing ionic iodine (I(-) and IO(3)(-)) and bromine (Br(-) and BrO(3)(-)) species are subjected to electrophoretic separation before injection into the microconcentric nebulizer (CEI-100). The separation has been achieved in a 50 cm length x 75 microm id fused-silica capillary. The electrophoretic buffer used is 10 mmol/L Tris (pH 8.0), while the applied voltage is set at -8 kV. Detection limits are 1 and 20-50 ng/mL for various I and Br compounds, respectively, based on peak height. The RSD of the peak areas for seven injections of 0.1 microg/mL I(-), IO(3)(-) and 1 microg/mL Br(-), BrO(3)(-) mixture is in the range of 3-5%. This method has been applied to determine various iodine and bromine species in NIST SRM 1573a Tomato Leaves reference material and a salt and seaweed samples obtained locally. A microwave-assisted extraction method is used for the extraction of these compounds. Over 87% of the total iodine and 83% of the total bromine are extracted using a 10% m/v tetramethylammonium hydroxide (TMAH) solution in a focused microwave field within a period of 10 min. The spike recoveries are in the range of 94-105% for all the determinations. The major species of iodine and bromine in tomato leaves, salt, and seaweed are Br(-), IO(3)(-), I(-), and Br(-), respectively.

  9. Distribution of copper, silver and gold during thermal treatment with brominated flame retardants

    SciTech Connect

    Oleszek, Sylwia; Grabda, Mariusz; Shibata, Etsuro; Nakamura, Takashi

    2013-09-15

    Highlights: • Copper, silver and gold during thermal treatment with brominated flame retardants. • Distribution of copper, silver and gold during thermal processing. • Thermodynamic considerations of the bromination reactions. - Abstract: The growing consumption of electric and electronic equipment results in creating an increasing amount of electronic waste. The most economically and environmentally advantageous methods for the treatment and recycling of waste electric and electronic equipment (WEEE) are the thermal techniques such as direct combustion, co-combustion with plastic wastes, pyrolysis and gasification. Nowadays, this kind of waste is mainly thermally treated in incinerators (e.g. rotary kilns) to decompose the plastics present, and to concentrate metals in bottom ash. The concentrated metals (e.g. copper, precious metals) can be supplied as a secondary raw material to metal smelters, while the pyrolysis of plastics allows the recovery of fuel gases, volatilising agents and, eventually, energy. Indeed, WEEE, such as a printed circuit boards (PCBs) usually contains brominated flame retardants (BFRs). From these materials, hydrobromic acid (HBr) is formed as a product of their thermal decomposition. In the present work, the bromination was studied of copper, silver and gold by HBr, originating from BFRs, such as Tetrabromobisphenol A (TBBPA) and Tetrabromobisphenol A-Tetrabromobisophenol A diglycidyl ether (TTDE) polymer; possible volatilization of the bromides formed was monitored using a thermo-gravimetric analyzer (TGA) and a laboratory-scale furnace for treating samples of metals and BFRs under an inert atmosphere and at a wide range of temperatures. The results obtained indicate that up to about 50% of copper and silver can evolve from sample residues in the form of volatile CuBr and AgBr above 600 and 1000 °C, respectively. The reactions occur in the molten resin phase simultaneously with the decomposition of the brominated resin. Gold is

  10. Brominated Biphenyls Prime Extensive Microbial Reductive Dehalogenation of Aroclor 1260 in Housatonic River Sediment

    PubMed Central

    Bedard, Donna L.; Van Dort, Heidi; Deweerd, Kim A.

    1998-01-01

    The upper Housatonic River and Woods Pond (Lenox, Mass.), a shallow impoundment on the river, are contaminated with polychlorinated biphenyls (PCBs), the residue of partially dechlorinated Aroclor 1260. Certain PCB congeners have the ability to activate or “prime” anaerobic microorganisms in Woods Pond sediment to reductively dehalogenate the Aroclor 1260 residue. We proposed that brominated biphenyls might have the same effect and tested the priming activities of 14 mono-, di-, and tribrominated biphenyls (350 μM) in anaerobic microcosms of sediment from Woods Pond. All of the brominated biphenyls were completely dehalogenated to biphenyl, and 13 of them primed PCB dechlorination. Measured in terms of chlorine removal and decrease in the proportion of hexa- through nonachlorobiphenyls, the microbial PCB dechlorination primed by several brominated biphenyls was nearly twice as effective as that primed by chlorinated biphenyls. Congeners containing a meta bromine primed Dechlorination Process N (flanked meta dechlorination), and congeners containing an unflanked para bromine primed Dechlorination Process P (flanked para dechlorination). Two ortho-substituted congeners, 2-bromobiphenyl and 2,6-dibromobiphenyl (2-BB and 26-BB), also primed Process N dechlorination. The most effective primers were 26-BB, 245-BB, 25-3-BB, and 25-4-BB. The microbial dechlorination primed by 26-BB converted ∼75% of the hexa- through nonachlorobiphenyls to tri- and tetrachlorobiphenyls in 100 days and removed ∼75% of the PCBs that are most persistent in humans. These results represent a major step toward identifying an effective method for accelerating PCB dechlorination in situ. The challenge now is to identify naturally occurring compounds that are safe and effective primers. PMID:9572952

  11. Monitoring of WEEE plastics in regards to brominated flame retardants using handheld XRF

    SciTech Connect

    Aldrian, Alexia; Ledersteger, Alfred; Pomberger, Roland

    2015-02-15

    Highlights: • Specification of an empirical factor for conversion from bromine to PBB and PBDE. • The handheld XRF device was validated for this particular application. • A very large number of over 4600 pieces of monitor housings was analysed. • The recyclable fraction mounts up to 85% for TV but only 53% of PC waste plastics. • A high percentage of pieces with bromine contents of over 50,000 ppm was obtained. - Abstract: This contribution is focused on the on-site determination of the bromine content in waste electrical and electronic equipment (WEEE), in particular waste plastics from television sets (TV) and personal computer monitors (PC) using a handheld X-ray fluorescence (XRF) device. The described approach allows the examination of samples in regards to the compliance with legal specifications for polybrominated biphenyls (PBBs) and polybrominated diphenyl ethers (PBDEs) directly after disassembling and facilitates the sorting out of plastics with high contents of brominated flame retardants (BFRs). In all, over 3000 pieces of black (TV) and 1600 pieces of grey (PC) plastic waste were analysed with handheld XRF technique for this study. Especially noticeable was the high percentage of pieces with a bromine content of over 50,000 ppm for TV (7%) and PC (39%) waste plastics. The applied method was validated by comparing the data of handheld XRF with results obtained by GC–MS. The results showed the expected and sufficiently accurate correlation between these two methods. It is shown that handheld XRF technique is an effective tool for fast monitoring of large volumes of WEEE plastics in regards to BFRs for on-site measurements.

  12. Enhanced ozone loss by active inorganic bromine chemistry in the tropical troposphere

    NASA Astrophysics Data System (ADS)

    Le Breton, Michael; Bannan, Thomas J.; Shallcross, Dudley E.; Khan, M. Anwar; Evans, Mathew J.; Lee, James; Lidster, Richard; Andrews, Stephen; Carpenter, Lucy J.; Schmidt, Johan; Jacob, Daniel; Harris, Neil R. P.; Bauguitte, Stephane; Gallagher, Martin; Bacak, Asan; Leather, Kimberley E.; Percival, Carl J.

    2017-04-01

    Bromine chemistry, particularly in the tropics, has been suggested to play an important role in tropospheric ozone loss although a lack of measurements of active bromine species impedes a quantitative understanding of its impacts. Recent modelling and measurements of bromine monoxide (BrO) by Wang et al. (2015) have shown current models under predict BrO concentrations over the Pacific Ocean and allude to a missing source of BrO. Here, we present the first simultaneous aircraft measurements of atmospheric bromine monoxide, BrO (a radical that along with atomic Br catalytically destroys ozone) and the inorganic Br precursor compounds HOBr, BrCl and Br2 over the Western Pacific Ocean from 0.5 to 7 km. The presence of 0.17-1.64 pptv BrO and 3.6-8 pptv total inorganic Br from these four species throughout the troposphere causes 10-20% of total ozone loss, and confirms the importance of bromine chemistry in the tropical troposphere; contributing to a 6 ppb decrease in ozone levels due to halogen chemistry. Observations are compared with a global chemical transport model and find that the observed high levels of BrO, BrCl and HOBr can be reconciled by active multiphase oxidation of halide (Br- and Cl-) by HOBr and ozone in cloud droplets and aerosols. Measurements indicate that 99% of the instantaneous free Br in the troposphere up to 8 km originates from inorganic halogen photolysis rather than from photolysis of organobromine species.

  13. Boiling of simulated tap water: effect on polar brominated disinfection byproducts, halogen speciation, and cytotoxicity.

    PubMed

    Pan, Yang; Zhang, Xiangru; Wagner, Elizabeth D; Osiol, Jennifer; Plewa, Michael J

    2014-01-01

    Tap water typically contains numerous halogenated disinfection byproducts (DBPs) as a result of disinfection, especially of chlorination. Among halogenated DBPs, brominated ones are generally significantly more toxic than their chlorinated analogues. In this study, with the aid of ultra performance liquid chromatography/electrospray ionization-triple quadrupole mass spectrometry by setting precursor ion scans of m/z 79/81, whole spectra of polar brominated DBPs in simulated tap water samples without and with boiling were revealed. Most polar brominated DBPs were thermally unstable and their levels were substantially reduced after boiling via decarboxylation or hydrolysis; the levels of a few aromatic brominated DBPs increased after boiling through decarboxylation of their precursors. A novel adsorption unit for volatile total organic halogen was designed, which enabled the evaluation of halogen speciation and mass balances in the simulated tap water samples during boiling. After boiling for 5 min, the overall level of brominated DBPs was reduced by 62.8%, of which 39.8% was volatilized and 23.0% was converted to bromide; the overall level of chlorinated DBPs was reduced by 61.1%, of which 44.4% was volatilized and 16.7% was converted to chloride; the overall level of halogenated DBPs was reduced by 62.3%. The simulated tap water sample without boiling was cytotoxic in a chronic (72 h) exposure to mammalian cells; this cytotoxicity was reduced by 76.9% after boiling for 5 min. The reduction in cytotoxicity corresponded with the reduction in overall halogenated DBPs. Thus, boiling of tap water can be regarded as a "detoxification" process and may reduce human exposure to halogenated DBPs through tap water ingestion.

  14. The effect of bromination of carbon fibers on the coefficient of thermal expansion of graphite fiber-epoxy composites

    NASA Technical Reports Server (NTRS)

    Jaworske, D. A.; Maciag, C.

    1987-01-01

    To examine the effect of bromination of carbon fibers on the coefficient of thermal expansion (CTE) of carbon fiber epoxy composites, several pristine and brominated carbon fiber-epoxy composite samples were subjected to thermomechanical analysis. The CTE's of these samples were measured in the uniaxial and transverse directions. The CTE was dominated by the fibers in the uniaxial direction, while it was dominated by the matrix in the transverse directions. Bromination had no effect on the CTE of any of the composites. In addition, the CTE of fiber tow was measured in the absence of a polymer matrix, using an extension probe. The results from this technique were inconclusive.

  15. Isotope separation by photochromatography

    DOEpatents

    Suslick, K.S.

    1975-10-03

    A photochromatographic method for isotope separation is described. An isotopically mixed molecular species is adsorbed on an adsorptive surface, and the adsorbed molecules are irradiated with radiation of a predetermined wavelength which will selectively excite desired isotopic species. Sufficient energy is transferred to the excited molecules to desorb them from the surface and thus separate them from the undesired isotopic species. The method is particularly applicable to the separation of hydrogen isotopes. (BLM)

  16. Isotope separation by photochromatography

    DOEpatents

    Suslick, Kenneth S.

    1977-01-01

    An isotope separation method which comprises physically adsorbing an isotopically mixed molecular species on an adsorptive surface and irradiating the adsorbed molecules with radiation of a predetermined wavelength which will selectively excite a desired isotopic species. Sufficient energy is transferred to the excited molecules to desorb them from the surface and thereby separate them from the unexcited undesired isotopic species. The method is particularly applicable to the separation of hydrogen isotopes.

  17. Combustion and inorganic bromine emission of waste printed circuit boards in a high temperature furnace

    SciTech Connect

    Ni Mingjiang; Xiao Hanxi; Chi Yong; Yan Jianhua; Buekens, Alfons; Jin Yuqi; Lu Shengyong

    2012-03-15

    Highlights: Black-Right-Pointing-Pointer The combustion efficiency of waste printed circuit boards (PCBs) depends on temperature, excess air factor, and high temperature zone residence time. Temperature has the most significant impact. Under the proposed condition, combustion of waste PCBs alone is quite complete within the furnace. Black-Right-Pointing-Pointer High temperature prompts a more complete bromine release and conversion. When temperature is high enough, 99.9% organobrominated compounds, the potential precursors for brominated dixoins formation, are destroyed efficiently and convert to inorganic bromine in flue gas, as HBr and Br{sub 2}. Black-Right-Pointing-Pointer Temperature has crucial influence over the inhibition of HBr conversion to Br{sub 2}, while the oxygen partial pressure plays a reverse role in the conversion to a very small extent. Increasing temperature will decrease the volume percentage ratio of Br{sub 2}/HBr in flue gas greatly. Black-Right-Pointing-Pointer The thermodynamic equilibrium approach of bromine conversion was investigated. The two forms of inorganic bromine in flue gas substantially reach thermodynamic equilibrium within 0.25 s. Under the proposed operating condition, the reaction of Br transfer and conversion finish. - Abstract: High temperature combustion experiments of waste printed circuit boards (PCBs) were conducted using a lab-scale system featuring a continuously-fed drop tube furnace. Combustion efficiency and the occurrence of inorganic bromine (HBr and Br{sub 2}) were systematically studied by monitoring the main combustion products continuously. The influence of furnace temperature (T) was studied from 800 to 1400 Degree-Sign C, the excess air factor (EAF) was varied from 1.2 to 1.9 and the residence time in the high temperature zone (RT{sub HT}) was set at 0.25, 0.5, or 0.75 s. Combustion efficiency depends on temperature, EAF and RT{sub HT}; temperature has the most significant effect. Conversion of organic

  18. Bromine Incorporation in Regulated and Emerging DBPs and the Relative Predominance of Mono, Di and Trihalogenated DBPs - SLIDES

    EPA Science Inventory

    Examination of bromine incorporation in emerging DBPs vs that of regulated DBPs Study of predominance of di- vs trihalogenated species in different DBP classes Better understand and characterize exposure to DBPs of health concern

  19. Bromine Incorporation in Regulated and Emerging DBPs and the Relative Predominance of Mono-, Di-, and Trihalogenated DBPs (Proceedings Paper)

    EPA Science Inventory

    Previous research has shown that bromine incorporation into trihalogenated acetic acids (TXAAs) was similar to that of the trihalomethanes (THMs). Likewise, occurrence data for other trihalogenated DBPs (e.g., halonitromethanes [HNMs], haloacetaldehydes [HAs]) showed similar or ...

  20. Hydroxylated polybrominated diphenyl ethers exhibit different activities on thyroid hormone receptors depending on their degree of bromination

    SciTech Connect

    Ren, Xiao-Min Guo, Liang-Hong Gao, Yu Zhang, Bin-Tian Wan, Bin

    2013-05-01

    Polybrominated diphenyl ethers (PBDEs) have been shown to disrupt thyroid hormone (TH) functions in experimental animals, and one of the proposed disruption mechanisms is direct binding of hydroxylated PBDE (OH-PBDE) to TH receptors (TRs). However, previous data on TH receptor binding and TH activity of OH-PBDEs were very limited and sometimes inconsistent. In the present paper, we examined the binding potency of ten OH-PBDEs with different degrees of bromination to TR using a fluorescence competitive binding assay. The results showed that the ten OH-PBDEs bound to TR with potency that correlated to their bromination level. We further examined their effect on TR using a coactivator binding assay and GH3 cell proliferation assay. Different TR activities of OH-PBDEs were observed depending on their degree of bromination. Four low-brominated OH-PBDEs (2′-OH-BDE-28, 3′-OH-BDE-28, 5-OH-BDE-47, 6-OH-BDE-47) were found to be TR agonists, which recruited the coactivator peptide and enhanced GH3 cell proliferation. However, three high-brominated OH-PBDEs (3-OH-BDE-100, 3′-OH-BDE-154, 4-OH-BDE-188) were tested to be antagonists. Molecular docking was employed to simulate the interactions of OH-PBDEs with TR and identify the structural determinants for TR binding and activity. According to the docking results, low-brominated OH-PBDEs, which are weak binders but TR agonists, bind with TR at the inner side of its binding pocket, whereas high-brominated compounds, which are potent binders but TR antagonists, reside at the outer region. These results indicate that OH-PBDEs have different activities on TR (agonistic or antagonistic), possibly due to their different binding geometries with the receptor. - Highlights: ► Thyroid hormone (TH) activity of OH-PBDEs with different Br number was evaluated. ► Four different experimental approaches were employed to investigate the mechanism. ► Low-brominated OH-PBDEs were agonists, but high-brominated ones were antagonists.

  1. A GC/ECNI-MS method for the identification of lipophilic anthropogenic and natural brominated compounds in marine samples.

    PubMed

    Vetter, W

    2001-10-15

    GC/ECNI-MS in both the full scan and selected ion monitoring modes was applied to study the patterns of brominated compounds in the blubber of marine mammals from a variety of locations. The adipose tissue of one polar bear was also studied. Occurrence of three major residues originating from the use of brominated flame-retardants (PBDE 47, 99, and 100) and several potential naturally occurring brominated compounds was studied in the samples. A series of three major natural brominated compounds (BC-1, BC-2, BC-3) recently identified in dolphins from Australia was included in this study. Two further brominated compounds, BC-10 and BC-11, were studied for the first time. ECNI-MS full scan spectra were obtained for BC-3 and BC-10. A natural mixed halogenated compound (MHC-1) and an unknown brominated compound (UBC-1) were investigated as well. Evidence for the natural production of these secondary metabolites and their bioaccumulation in higher organisms as well as analytical protocols for their detection in the environment are presented. Some of these naturally occurring compounds may be misinterpreted as anthropogenic brominated compounds. In ECNI-MS, brominated compounds are usually identified by the detection of the fragment ions m/z 79 ([79Br]-) and m/z 81 ([81Br]-). In this work, it is shown that monitoring of additional ion traces corresponding to [Br2]- (160 type), [HBr2]- (161 type), [BrCl]- (116 type), and [HBrCl]- (117 type) fragment ions allows distinguishing between different classes of brominated compounds. This technique was used to demonstrate that UBC-1 is neither a PBDE nor a PBB congener, whereas a second mixed halogenated compound (MHC-2) was identified as a result of the ECNI-MS response at m/z 114/116. Studies on blubber extracts of marine mammals from four continents resulted in the detection of significant differences in the global distribution of brominated compounds. Our results suggest that naturally occurring organobromines are more

  2. Distribution of Halon-1211 in the Upper Troposphere and Lower Stratosphere and the 1994 Total Bromine Budget. Appendix E

    NASA Technical Reports Server (NTRS)

    Wamsley, P. R.; Elkins, J. W.; Fahey, D. W.; Dutton, G. S.; Volk, C. M.; Myers, R. C.; Montzka, S. A.; Butler, J. H.; Clarke, A. D.; Fraser, P. J.

    1998-01-01

    We report here on the details of the first, in situ, real-time measurements of H-1211 (CBrClF2) and sulfur hexafluoride (SF6) mixing ratios in the stratosphere up to 20 km. Stratospheric air was analyzed for these gases and others with a new gas chromatograph, flown aboard a National Aeronautics and Space Administration ER-2 aircraft as part of the Airborne Southern Hemisphere Ozone Experiment/Measurements for Assessing the Effects of Stratospheric Aircraft mission conducted in 1994. The mixing ratio of SF6, with its nearly linear increase in the troposphere, was used to estimate the mean age of stratospheric air parcels along the ER-2 flight path. Measurements of H-1211 and mean age estimates were then combined with simultaneous measurements of CFC-11 (CCl3F), measurements of brominated compounds in stratospheric whole air samples, and records of tropospheric organic bromine mixing ratios to calculate the dry mixing ratio of total bromine in the lower stratosphere and its partitioning between organic and inorganic forms. We estimate that the organic bromine-containing species were almost completely photolyzed to inorganic species in the oldest air parcels sampled. Our results for inorganic bromine are consistent with those obtained from a photochemical, steady state model for stratospheric air parcels with CFC- I I mixing ratios greater than 150 ppt. For stratospheric air parcels with CFC-11 mixing ratios less than 50 ppt (mean age greater than or equal to 5 years) we calculate inorganic bromine mixing ratios that are approximately 20% less than the photo-chemical, steady state model. There is a 20% reduction in calculated ozone loss resulting from bromine chemistry in old air relative to some previous estimates as a result of the lower bromine levels.

  3. Modification of Polystyrene/Polybutadiene Block Copolymer Films by Chemical Reaction with Bromine and Effect on Gas Permeability

    DTIC Science & Technology

    1990-06-15

    polystyrene/polybutadiene ( PS /PB) block copolymer films before and after reaction with aqueous bromine. Films reacted to low and very high extents...enhancement relative to the starting PS /PB system. These effects on permeability are the combined result of physical and chemical changes in the block...heterogeneous polystyrene/polybutadiene ( PS /PB) block copolymer films before and after reaction with aqueous bromine. Films reacted to low and very

  4. In vivo speciation studies and antioxidant properties of bromine in Laminaria digitata reinforce the significance of iodine accumulation for kelps.

    PubMed

    Küpper, Frithjof C; Carpenter, Lucy J; Leblanc, Catherine; Toyama, Chiaki; Uchida, Yuka; Maskrey, Benjamin H; Robinson, Joanne; Verhaeghe, Elodie F; Malin, Gill; Luther, George W; Kroneck, Peter M H; Kloareg, Bernard; Meyer-Klaucke, Wolfram; Muramatsu, Yasuyuki; Megson, Ian L; Potin, Philippe; Feiters, Martin C

    2013-07-01

    The metabolism of bromine in marine brown algae remains poorly understood. This contrasts with the recent finding that the accumulation of iodide in the brown alga Laminaria serves the provision of an inorganic antioxidant - the first case documented from a living system. The aim of this study was to use an interdisciplinary array of techniques to study the chemical speciation, transformation, and function of bromine in Laminaria and to investigate the link between bromine and iodine metabolism, in particular in the antioxidant context. First, bromine and iodine levels in different Laminaria tissues were compared by inductively coupled plasma MS. Using in vivo X-ray absorption spectroscopy, it was found that, similarly to iodine, bromine is predominantly present in this alga in the form of bromide, albeit at lower concentrations, and that it shows similar behaviour upon oxidative stress. However, from a thermodynamic and kinetic standpoint, supported by in vitro and reconstituted in vivo assays, bromide is less suitable than iodide as an antioxidant against most reactive oxygen species except superoxide, possibly explaining why kelps prefer to accumulate iodide. This constitutes the first-ever study exploring the potential antioxidant function of bromide in a living system and other potential physiological roles. Given the tissue-specific differences observed in the content and speciation of bromine, it is concluded that the bromide uptake mechanism is different from the vanadium iodoperoxidase-mediated uptake of iodide in L. digitata and that its function is likely to be complementary to the iodide antioxidant system for detoxifying superoxide.

  5. Isolation of brominated long-chain fatty acids from the phospholipids of the tropical marine sponge Amphimedon terpenensis.

    PubMed

    Garson, M J; Zimmermann, M P; Hoberg, M; Larsen, R M; Battershill, C N; Murphy, P T

    1993-11-01

    Preliminary investigation of the phospholipid fatty acid composition of the tropical marine sponge Amphimedon terpenensis by gas chromatography/mass spectrometry revealed the presence of some novel brominated fatty acids. Two new brominated fatty acids, (5E, 9Z)-6-bromo-5,9-tetracosadienoic acid (2a) and (5E, 9Z)-6-bromo-5,9-pentacosadienoic acid (3a) were subsequently isolated from a chloroform/methanol (3:1, vol/vol) extract of the sponge and characterized as their methyl esters 2b and 3b. The known brominated fatty acid (5E, 9Z)-6-bromo-5,9-hexacosadienoic acid (4a) was also isolated. The new fatty acid methyl esters were confirmed as brominated delta 5,9 acid derivatives by chemical ionization mass spectrometry. The position of the bromine substituent was determined to be C-6 by nuclear magnetic resonance techniques while the stereochemistry of the two double bonds was deduced by nuclear Overhauser enhancement difference spectroscopy. The biosynthetic implications of the co-occurrence of the three brominated acids are discussed.

  6. Analysis and occurrence of emerging brominated flame retardants in the Llobregat River basin

    NASA Astrophysics Data System (ADS)

    Guerra, Paula; Eljarrat, Ethel; Barceló, Damià

    2010-03-01

    SummaryIn response to increasing international regulations on brominated flame retardants (BFR) formulations, alternative additive flame retardants for achieving commercial product fire safety standards are being developed and used. Some of these non-BDE (brominated diphenyl ethers) BFRs are pentabromoethylbenzene (PBEB), hexabromobenzene (hexaBBz), and decabromodiphenylethane (deBDethane). The present study investigated the occurrence of these emerging BFRs, together with 38 BDE congeners (from di- to deca-BDE) in sediments sampled from different points along Llobregat basin (Spain) in three different sampling campaigns between 2005 and 2006. Emerging BFRs were detected in all sediment samples analyzed, at concentrations ranging from 3.1 to 9.6 ng/g for PBEB, from 0.4 to 2.4 ng/g for hexaBBz and from 4.8 to 23 ng/g for deBDethane. These levels are lower than concentrations obtained for PBDEs (from nd to 82 ng/g).

  7. Advances in Instrumental Analysis of Brominated Flame Retardants: Current Status and Future Perspectives

    PubMed Central

    2014-01-01

    This review aims to highlight the recent advances and methodological improvements in instrumental techniques applied for the analysis of different brominated flame retardants (BFRs). The literature search strategy was based on the recent analytical reviews published on BFRs. The main selection criteria involved the successful development and application of analytical methods for determination of the target compounds in various environmental matrices. Different factors affecting chromatographic separation and mass spectrometric detection of brominated analytes were evaluated and discussed. Techniques using advanced instrumentation to achieve outstanding results in quantification of different BFRs and their metabolites/degradation products were highlighted. Finally, research gaps in the field of BFR analysis were identified and recommendations for future research were proposed. PMID:27433482

  8. A review of mathematical modeling of the zinc/bromine flow cell and battery

    NASA Astrophysics Data System (ADS)

    Evans, T. I.; White, R. E.

    1987-11-01

    Mathematical models which have been developed to study various aspects of the zinc/bromine cell and stack of cells are reviewed. Development of these macroscopic models begins with a material balance, a transport equation which includes a migration term for charged species in an electric field, and an electrode kinetic expression. Various types of models are discussed: partial differential equation models that can be used to predict current and potential distributions, an algebraic model that includes shunt currents and associated energy losses and can be used to determine the optimum resistivity of an electrolyte, and ordinary differential equation models that can be used to predict the energy efficiency of the cell as a function of the state of charge. These models have allowed researchers to better understand the physical phenomena occurring within parallel plate electrochemical flow reactors and have been instrumental in the improvement of the zinc/bromine cell design. Suggestions are made for future modeling work.

  9. Stratospheric ozone depletion and future levels of atmospheric chlorine and bromine

    NASA Technical Reports Server (NTRS)

    Prather, Michael J.; Watson, Robert T.

    1990-01-01

    The rise in atmospheric chlorine levels caused by the emission of chlorofluorocarbons and other halocarbons is thought to be the main cause of the appearance of the Antarctic ozone 'hole' in the late 1970s, and the more modest ozone depletion observed over parts of the Northern Hemisphere. Atmospheric bromine, also associated with halocarbon emissions, is believed to contribute to ozone depletion. Over the next decade, further increases in these compounds are inevitable. Model calculations show that by the end of the next century, atmospheric chlorine and bromine levels may return to those prevalent before the onset of the ozone hole, but only if more stringent regulations are applied to halocarbon production than those currently proposed.

  10. Bromine and Iodine Contents in Raw and Cooked Shrimp and Its Parts.

    PubMed

    Mesko, Marcia F; Toralles, Isis G; Hartwig, Carla A; Coelho, Gilberto S; Muller, Aline L H; Bizzi, Cezar A; Mello, Paola A

    2016-03-02

    The concentration of bromine and iodine was determined in shrimp and its parts (tissue and shells), and changes in the analyte concentration were evaluated after the cooking procedure. Bromine and iodine concentrations were determined by a method recently developed by our research group based on microwave-induced combustion for sample preparation and inductively coupled plasma mass spectrometry for analyte determination. The accuracy was evaluated using a reference material (NIST 8414) that was digested using the proposed method. No statistical difference was observed between certified and determined values (Student's t test, 95% confidence level). Suitable limits of detection (Br, 0.02 μg g(-1) and I, 0.01 μg g(-1)) were obtained for both analytes. Higher concentrations of both analytes were observed in shrimp shells in comparison to shrimp tissue for raw and cooked samples. Moreover, losses of Br and I (between 24 and 43%) were observed after cooking.

  11. Dehalogenation of arenes via SN2 reactions at bromine: competition with nucleophilic aromatic substitution.

    PubMed

    Gronert, Scott; Garver, John M; Nichols, Charles M; Worker, Benjamin B; Bierbaum, Veronica M

    2014-11-21

    The gas-phase reactions of carbon- and nitrogen-centered nucleophiles with polyfluorobromobenzenes were examined in a selected-ion flow tube (SIFT) and modeled computationally at the MP2/6-31+G(d,p)//MP2/6-31+G(d) level. In the gas-phase experiments, rate constants and branching ratios were determined. The carbon nucleophiles produce expected nucleophilic aromatic substitution (SNAr) and proton transfer products along with unexpected products that result from SN2 reactions at the bromine center (polyfluorophenide leaving group). With nitrogen nucleophiles, the SN2 at bromine channel is suppressed. In the SNAr channels, the "element effect" is observed, and fluoride loss competes with bromide loss. The computational modeling indicates that all the substitution barriers are well below the entrance channel and that entropy and dynamics effects control the product distributions.

  12. Molten-Phase Hydrolysis Stage Analysis and Experiments for the Calcium Bromine Thermochemical Cycle

    SciTech Connect

    Doctor, Richard D.; Panchal, C.B.; Lottes, Steven A.; Lyczkowski, Robert W.; Yang, Jianhong

    2007-07-01

    The goal of the United States Department of Energy Nuclear Hydrogen Initiative as linked with the Generation IV Nuclear Energy Systems Initiative for Gas Reactor Deployment is to develop a cost-effective, proliferation-resistant, low-greenhouse-gas emissions, and sustainable, nuclear-based energy supply system. The calcium-bromine cycle under development at Argonne National Laboratory combines both experimental and modeling studies of a novel continuous 'hybrid' cycle for hydrogen production, where 'hybrid' means that both nuclear heat and electricity are employed. Engineering the calcium-bromine cycle for continuous operation should facilitate its practical development since there will be an inherent advantage to using components and materials which will operate in a constant, non-cycling chemical and thermal environment. This paper focuses on the first and important calcium bromide hydrolysis stage to generate hydrogen bromide, which when split by electrolysis, produces hydrogen. (authors)

  13. Anomalous bond length behavior and a new solid phase of bromine under pressure

    PubMed Central

    Wu, Min; Tse, John S.; Pan, Yuanming

    2016-01-01

    The behavior of diatomic molecular solids under pressure have attracted great interest and been extensively studied. Under ambient pressure, the structure of bromine is known to be a molecular phase (phase I). With increasing pressure, it transforms into an incommensurate phase (phase V) before eventually to a monoatomic phase (phase II). However, between phases I and V, the interatomic distance was found to first increase with pressure and then decreased abruptly. This anomalous bond length behavior is accompanied by the splitting of the Raman bands. These phenomena have not been resolved. Here we suggest a new solid phase that explains the Raman spectra. Furthermore, the anomalous bond length behavior is found to be the result of subtle second neighbor intermolecular interactions and is an intrinsic property of bromine in molecular phases. PMID:27156710

  14. Design of bipolar, flowing-electrolyte zinc-bromine electric-vehicle battery systems

    NASA Astrophysics Data System (ADS)

    Malachesky, P. A.; Bellows, R. J.; Einstein, H. E.; Grimes, P. G.; Newby, K.; Young, A.

    1983-01-01

    The integration of bipolar, flowing electrolyte zinc-bromine technology into a viable electric vehicle battery system requires careful analysis of the requirements placed on the battery system by the EV power train. In addition to the basic requirement of an appropriate battery voltage and power density, overall battery system energy efficiency must also be considered and parasitic losses from auxiliaries such as pumps and shunt current protection minimized. An analysis of the influence of these various factors on zinc-bromine EV battery system design has been carried out for two types of EV propulsion systems. The first of these is a nominal 100V dc system, while the second is a high voltage (200V dc) system as might be used with an advanced design ac propulsion system. Battery performance was calculated using an experimentally determined relationship which expresses battery voltage as a function of current density and state-of-charge.

  15. The effect of representing bromine from VSLS on the simulation and evolution of Antarctic ozone

    NASA Astrophysics Data System (ADS)

    Oman, Luke D.; Douglass, Anne R.; Salawitch, Ross J.; Canty, Timothy P.; Ziemke, Jerald R.; Manyin, Michael

    2016-09-01

    We use the Goddard Earth Observing System Chemistry-Climate Model, a contributor to both the 2010 and 2014 World Meteorological Organization Ozone Assessment Reports, to show that inclusion of 5 parts per trillion (ppt) of stratospheric bromine (Bry) from very short lived substances (VSLS) is responsible for about a decade delay in ozone hole recovery. These results partially explain the significantly later recovery of Antarctic ozone noted in the 2014 report, as bromine from VSLS was not included in the 2010 Assessment. We show multiple lines of evidence that simulations that account for VSLS Bry are in better agreement with both total column BrO and the seasonal evolution of Antarctic ozone reported by the Ozone Monitoring Instrument on NASA's Aura satellite. In addition, the near-zero ozone levels observed in the deep Antarctic lower stratospheric polar vortex are only reproduced in a simulation that includes this Bry source from VSLS.

  16. Anomalous bond length behavior and a new solid phase of bromine under pressure

    NASA Astrophysics Data System (ADS)

    Wu, Min; Tse, John S.; Pan, Yuanming

    2016-05-01

    The behavior of diatomic molecular solids under pressure have attracted great interest and been extensively studied. Under ambient pressure, the structure of bromine is known to be a molecular phase (phase I). With increasing pressure, it transforms into an incommensurate phase (phase V) before eventually to a monoatomic phase (phase II). However, between phases I and V, the interatomic distance was found to first increase with pressure and then decreased abruptly. This anomalous bond length behavior is accompanied by the splitting of the Raman bands. These phenomena have not been resolved. Here we suggest a new solid phase that explains the Raman spectra. Furthermore, the anomalous bond length behavior is found to be the result of subtle second neighbor intermolecular interactions and is an intrinsic property of bromine in molecular phases.

  17. Thermal Recycling of Brominated Flame Retardants with Fe2O3.

    PubMed

    Altarawneh, Mohammednoor; Ahmed, Oday H; Jiang, Zhong-Tao; Dlugogorski, Bogdan Z

    2016-08-04

    Plastics containing brominated flame retardants (BFRs) constitute the major fraction of nonmetallic content in e-waste. Co-pyrolysis of BFRs with hematite (Fe2O3) represents a viable option for the thermal recycling of BFRs. Consensus of experimental findings confirms the excellent bromine fixation ability of Fe2O3 and the subsequent formation of iron bromides. This contribution provides a comprehensive mechanistic account of the primary reactions between a cluster model of Fe2O3 and major bromine-bearing products from the decomposition of tetrabromobisphenol A (TBBA), the most commonly deployed BFR. We estimate the thermo-kinetic parameters for interactions of Fe2O3 with HBr, brominated alkanes and alkenes, bromobenzene, and bromophenol. Dissociative addition of HBr at a Fe-O bond proceeds through a trivial barrier of 8.2 kcal/mol with fitted parameters in the Arrhenius equation of k(T) = 7.96 × 10(11) exp(-6400/RT) s(-1). The facile and irreversible nature for HBr addition to Fe2O3 accords with the experimentally reported 90% reduction in HBr emission when Fe2O3 interacts with TBBA pyrolysates. A detailed kinetic analysis indicates that, transformation of Fe2O3 into iron bromides and oxybromides occurs via successive addition of HBr to Fe(Br)-O(H) entities. Elimination of a water molecule proceeds through an intramolecular H transfer. A direct elimination one-step mechanism operates in the dehydrohalogenation of bromoethane into ethene over Fe2O3. Dissociative decomposition and direct elimination channels assume comparable reaction rates in formation of acetylene from vinyl bromide. Results from this study provide an atomic-based insight into a promising thermal recycling route of e-waste.

  18. Surface ozone depletion in Arctic spring sustained by bromine reactions on aerosols

    NASA Astrophysics Data System (ADS)

    Fan, Song-Miao; Jacob, Daniel J.

    1992-10-01

    NEAR-TOTAL depletion of the ozone in surface air is often observed in the Arctic spring, coincident with high atmospheric concentrations of inorganic bromine. A mechanism based on known aqueous-phase chemistry is proposed which rapidly converts HBr, HOBr, and BrNO3 back to Br and BrO radicals. This mechanism should be particularly efficient in the presence of the high concentrations of sulphuric acid aerosols observed during ozone depletion events.

  19. Combustion and inorganic bromine emission of waste printed circuit boards in a high temperature furnace.

    PubMed

    Ni, Mingjiang; Xiao, Hanxi; Chi, Yong; Yan, Jianhua; Buekens, Alfons; Jin, Yuqi; Lu, Shengyong

    2012-03-01

    High temperature combustion experiments of waste printed circuit boards (PCBs) were conducted using a lab-scale system featuring a continuously-fed drop tube furnace. Combustion efficiency and the occurrence of inorganic bromine (HBr and Br(2)) were systematically studied by monitoring the main combustion products continuously. The influence of furnace temperature (T) was studied from 800 to 1400°C, the excess air factor (EAF) was varied from 1.2 to 1.9 and the residence time in the high temperature zone (RT(HT)) was set at 0.25, 0.5, or 0.75 s. Combustion efficiency depends on temperature, EAF and RT(HT); temperature has the most significant effect. Conversion of organic bromine from flame retardants into HBr and Br(2) depends on temperature and EAF. Temperature has crucial influence over the ratio of HBr to Br(2), whereas oxygen partial pressure plays a minor role. The two forms of inorganic bromine seem substantially to reach thermodynamic equilibrium within 0.25s. High temperature is required to improve the combustion performance: at 1200°C or higher, an EAF of 1.3 or more, and a RT(HT) exceeding 0.75 s, combustion is quite complete, the CO concentration in flue gas and remained carbon in ash are sufficiently low, and organobrominated compounds are successfully decomposed (more than 99.9%). According to these results, incineration of waste PCBs without preliminary separation and without additives would perform very well under certain conditions; the potential precursors for brominated dioxins formation could be destroyed efficiently. Increasing temperature could decrease the volume percentage ratio of Br(2)/HBr in flue gas greatly.

  20. Study of the liquid vapor equilibrium in the bromine-hydrobromic acid-water system

    NASA Technical Reports Server (NTRS)

    Benizri, R.; Lessart, P.; Courvoisier, P.

    1984-01-01

    A glass ebullioscope was built and at atmospheric pressure, liquid-vapor equilibria relative to the Br2-HBr-H2O system, in the concentration range of interest for evaluation of the Mark 13 cycle was studied. Measurements were performed for the brome-azeotrope (HBr-H2O) pseudo-binary system and for the ternary system at temperatures lower than 125 C and in the bromine concentration range up to 13% wt.

  1. Dependence of mass spectrometric fragmentation on the bromine substitution pattern of polybrominated diphenyl ethers.

    PubMed

    Wei, Hua; Zhang, Siyu; Wang, Yawei; Wang, Ying; Li, An; Negrusz, Adam; Yu, Gang

    2014-06-01

    This study investigates the link between the bromine substitution and the mass spectrometric fragmentation of polybrominated diphenyl ethers (PBDEs). The mass spectra of 180 PBDEs were obtained in both electron impact (EI) and electron capture negative ionization (ECNI) modes using a single quadrupole mass spectrometer (MS) as well as EI using a tandem MS (MS/MS). The major ions are M(+), [M-2Br](+), [M-2Br](2+) and [M-nBr-28](+) in EI, and Br(-), [HBr2](-) and [C6BrnO](-) in ECNI. In EI-MS, congeners without ortho bromine or having 2,3 substitution on one ring and no ortho bromines on the other were more robust than the others in each homolog. These congeners generated low [M-2Br](+) but relatively high [M-2Br](2+) in EI-MS and negligible [HBr2](-) in ECNI-MS. In EI-MS/MS, the molecular ions of these congeners required higher collision energy to debrominate, and produced additional ions of [M-nBr](+) and [M-nBr-28](+). Full ortho substitution promotes C-O cleavage forming [C6BrnO](-) in ECNI for congeners with >5 bromines. The relationship between the abundance of M(+) and collision energy of the EI-MS/MS was well characterized with a logistic regression model. Principle component analysis found associations between the inflection point collision energy and a few molecular descriptors. Quantum chemistry simulations revealed different EI-induced fragmentation mechanisms among four dibrominated congeners, supporting the hypothesized formation of a stable dibenzofuran-like intermediate during the fragmentation of some congeners but not of others.

  2. Tropospheric bromine chemistry: implications for present and pre-industrial ozone and mercury

    NASA Astrophysics Data System (ADS)

    Parrella, J. P.; Jacob, D. J.; Liang, Q.; Zhang, Y.; Mickley, L. J.; Miller, B.; Evans, M. J.; Yang, X.; Pyle, J. A.; Theys, N.; Van Roozendael, M.

    2012-04-01

    We present a new model for the global tropospheric chemistry of inorganic bromine (Bry) coupled to oxidant-aerosol chemistry in the GEOS-Chem chemical transport model (CTM). Sources of tropospheric Bry include debromination of sea-salt aerosol, photolysis and oxidation of short-lived bromocarbons, and transport from the stratosphere. Comparison to a GOME-2 satellite climatology of tropospheric BrO columns shows that the model can reproduce the observed increase of BrO with latitude, the northern mid-latitudes maximum in winter, and the Arctic maximum in spring. This successful simulation is contingent on the HOBr + HBr reaction taking place in aqueous aerosols and ice clouds. Bromine chemistry in the model decreases tropospheric ozone concentrations by <1-8 nmol mol-1 (6.5% globally), with the largest effects in the northern extratropics in spring. The global mean tropospheric OH concentration decreases by 4%. Inclusion of bromine chemistry improves the ability of global models (GEOS-Chem and p-TOMCAT) to simulate observed 19th-century ozone and its seasonality. Bromine effects on tropospheric ozone are comparable in the present-day and pre-industrial atmospheres so that estimates of anthropogenic radiative forcing are minimally affected. Br atom concentrations are 40% higher in the pre-industrial atmosphere due to lower ozone, which would decrease by a factor of 2 the atmospheric lifetime of elemental mercury against oxidation by Br. This suggests that historical anthropogenic mercury emissions may have mostly deposited to northern mid-latitudes, enriching the corresponding surface reservoirs. The persistent rise in background surface ozone at northern mid-latitudes during the past decades could possibly contribute to the observations of elevated mercury in subsurface waters of the North Atlantic.

  3. Tropospheric bromine chemistry: implications for present and pre-industrial ozone and mercury

    NASA Astrophysics Data System (ADS)

    Parrella, J. P.; Jacob, D. J.; Liang, Q.; Zhang, Y.; Mickley, L. J.; Miller, B.; Evans, M. J.; Yang, X.; Pyle, J. A.; Theys, N.; Van Roozendael, M.

    2012-08-01

    We present a new model for the global tropospheric chemistry of inorganic bromine (Bry) coupled to oxidant-aerosol chemistry in the GEOS-Chem chemical transport model (CTM). Sources of tropospheric Bry include debromination of sea-salt aerosol, photolysis and oxidation of short-lived bromocarbons, and transport from the stratosphere. Comparison to a GOME-2 satellite climatology of tropospheric BrO columns shows that the model can reproduce the observed increase of BrO with latitude, the northern mid-latitudes maximum in winter, and the Arctic maximum in spring. This successful simulation is contingent on the HOBr + HBr reaction taking place in aqueous aerosols and ice clouds. Bromine chemistry in the model decreases tropospheric ozone mixing ratios by <1-8 nmol mol-1 (6.5% globally), with the largest effects in the northern extratropics in spring. The global mean tropospheric OH concentration decreases by 4%. Inclusion of bromine chemistry improves the ability of global models (GEOS-Chem and p-TOMCAT) to simulate observed 19th-century ozone and its seasonality. Bromine effects on tropospheric ozone are comparable in the present-day and pre-industrial atmospheres so that estimates of anthropogenic radiative forcing are minimally affected. Br atom concentrations are 40% higher in the pre-industrial atmosphere due to lower ozone, which would decrease by a factor of 2 the atmospheric lifetime of elemental mercury against oxidation by Br. This suggests that historical anthropogenic mercury emissions may have mostly deposited to northern mid-latitudes, enriching the corresponding surface reservoirs. The persistent rise in background surface ozone at northern mid-latitudes during the past decades could possibly contribute to the observations of elevated mercury in subsurface waters of the North Atlantic.

  4. Tropospheric Bromine Chemistry: Implications for Present and Pre-industrial Ozone and Mercury

    NASA Technical Reports Server (NTRS)

    Parella, J. P.; Jacob, D. J.; Liang, Q.; Zhang, Y.; Mickley, L. J.; Miller, B.; Evans, M. J.; Yang, X.; Pyle, J. A.; Theys, N.; VanRoozendael, M.

    2012-01-01

    We present a new model for the global tropospheric chemistry of inorganic bromine (Bry) coupled to oxidant-aerosol chemistry in the GEOS-Chem chemical transport model (CTM). Sources of tropospheric Bry include debromination of sea-salt aerosol, photolysis and oxidation of short-lived bromocarbons, and transport from the stratosphere. Comparison to a GOME-2 satellite climatology of tropospheric BrO columns shows that the model can reproduce the observed increase of BrO with latitude, the northern mid-latitudes maximum in winter, and the Arctic maximum in spring. This successful simulation is contingent on the HOBr + HBr reaction taking place in aqueous aerosols and ice clouds. Bromine chemistry in the model decreases tropospheric ozone mixing ratios by <1-8 nmol/mol (6.5% globally), with the largest effects in the northern extratropics in spring. The global mean tropospheric OH concentration decreases by 4 %. Inclusion of bromine chemistry improves the ability of global models (GEOS-Chem and p-TOMCAT) to simulate observed 19th-century ozone and its seasonality. Bromine effects on tropospheric ozone are comparable in the present-day and pre-industrial atmospheres so that estimates of anthropogenic radiative forcing are minimally affected. Br atom concentrations are 40% higher in the pre-industrial atmosphere due to lower ozone, which would decrease by a factor of 2 the atmospheric lifetime of elemental mercury against oxidation by Br. This suggests that historical anthropogenic mercury emissions may have mostly deposited to northern mid-latitudes, enriching the corresponding surface reservoirs. The persistent rise in background surface ozone at northern mid-latitudes during the past decades could possibly contribute to the observations of elevated mercury in subsurface waters of the North Atlantic.

  5. Heterogeneous processing of bromine compounds by atmospheric aerosols: Relation to the ozone budget

    SciTech Connect

    Robinson, J.M.; Henson, B.F.; Dubey, M.K.; Casson, J.L.; Johal, M.S.; Wilson, K.R.

    1998-11-01

    This is the final report of a three-year, Laboratory Directed Research and Development (LDRD) project at Los Alamos National Laboratory (LANL). The depletion of ozone, particularly above Antarctica, has been investigated extensively to formulate public policy on the use of halocarbons. While it has been shown that heterogeneous reactions of chlorine compounds on stratospheric particulates cause the ozone hole, little is known of the analogous bromine mechanisms, even though it has been recognized for two decades that catalytic destruction of ozone by bromine could be more efficient than chlorine. Furthermore, field measurements and modeling calculations suggest that these heterogeneous (gas/surface) reactions are not restricted to the Antarctic regions but occur globally. The authors have performed laboratory measurements of the uptake of bromine compounds and other halogens on simulated stratospheric aerosols to help elucidate their role in catalytic ozone destruction cycles. Their studies contribute to the data base required to make assessments of the effects of human activities on global change, including the Montreal Protocol.

  6. Mechanochemical conversion of brominated POPs into useful oxybromides: a greener approach

    NASA Astrophysics Data System (ADS)

    Cagnetta, Giovanni; Liu, Han; Zhang, Kunlun; Huang, Jun; Wang, Bin; Deng, Shubo; Wang, Yujue; Yu, Gang

    2016-06-01

    Brominated organic pollutants are considered of great concern for their adverse effect on human health and the environment, so an increasing number of such compounds are being classified as persistent organic pollutants (POPs). Mechanochemical destruction is a promising technology for POPs safe disposal because it can achieve their complete carbonization by solvent-free high energy ball milling at room temperature. However, a large amount of co-milling reagent usually is necessary, so a considerable volume of residue is produced. In the present study a different approach to POPs mechanochemical destruction is proposed. Employing stoichiometric quantities of Bi2O3 or La2O3 as co-milling reagent, brominated POPs are selectively and completely converted into their corresponding oxybromides (i.e. BiOBr and LaOBr), which possess very peculiar properties and can be used for some actual and many more potential applications. In this way, bromine is beneficially reused in the final product, while POPs carbon skeleton is safely destroyed to amorphous carbon. Moreover, mechanochemical destruction is employed in a greener and more sustainable manner.

  7. Brominated and organophosphate flame retardants in selected consumer products on the Japanese market in 2008.

    PubMed

    Kajiwara, Natsuko; Noma, Yukio; Takigami, Hidetaka

    2011-09-15

    The concentrations of traditional brominated flame retardants (BFRs) and organophosphate flame retardants (OPFRs) in new consumer products, including electronic equipment, curtains, wallpaper, and building materials, on the Japanese market in 2008 were investigated. Although some components of the electronic equipment contained bromine at concentrations on the order of percent by weight, as indicated by X-ray fluorescence analysis, the bromine content could not be fully accounted for by the BFRs analyzed in this study, which included polybrominated diphenylethers, decabromodiphenyl ethane, tetrabromobisphenol A, polybromophenols, and hexabromocyclododecanes. These results suggest the use of alternative BFRs such as newly developed formulations derived from tribromophenol, tetrabromobisphenol A, or both. Among the 11 OPFRs analyzed, triphenylphosphate was present at the highest concentrations in all the products investigated, which suggests the use of condensed-type OPFRs as alternative flame retardants, because they contain triphenylphosphate as an impurity. Tripropylphosphate was not detected in any samples; and trimethylphosphate, tributyl tris(2-butoxyethyl)phosphate, and tris(1,3-dichloro-2-propyl)phosphate were detected in only some components and at low concentrations. Note that all the consumer products evaluated in this study also contained traditional BFRs in amounts that were inadequate to impart flame retardancy, which implies the incorporation of recycled plastic materials containing BFRs that are of global concern.

  8. A new brominated polymeric additive for flame retardant glass-filled polybutylene terephthalate

    NASA Technical Reports Server (NTRS)

    Nir, Z.; Kourtides, D. A.; Parker, J. A.; Bar-Yaacov, Y.; Minke, R.; Touval, I.

    1982-01-01

    Attention is called to the undesirable effects (poor ultraviolet light stability and blooming) sometimes introduced by brominated flame retarders. A brominated polymeric additive (BPA) with little or none of these undesirable side effects is compared with decabromobiphenyl oxide (DBBPO). The additive bears the product name F-2300. It is found to be more easily dispersed than DBBPO. The F-2300 is as effective as the DBBPO in the oxygen index test. The improved efficiency of the F-2300 may be explained by its better dispersion in polybutylene terephthalate (PBT). Glass-filled PBT containing F-2300 is found to be more resistant to UV degradation than DBBPO-containing formulas. Formulations with F-2300 therefore have a longer useful outdoor life. F-2300 is a diglycidyl-type polymer containing 50 percent aromatically bound bromine. Its melting point is 112 C, and it is stable up to 372 C. It is pointed out that since its melts at a relatively low temperature, it can be introduced into the formulation as a large agglomerate and still be dispersed evenly throughout the polymer.

  9. Mono- and di-bromo platinum(IV) prodrugs via oxidative bromination: synthesis, characterization, and cytotoxicity.

    PubMed

    Xu, Zoufeng; Wang, Zhigang; Yiu, Shek-Man; Zhu, Guangyu

    2015-12-14

    Platinum(IV)-based anticancer prodrugs have attracted much attention due to their relative inertness under physiological conditions, being activated inside cells, and their capacity for functionalization with a variety of small-molecule or macromolecule moieties. Novel asymmetric platinum(IV) compounds synthesized through expedient and unique methods are desired. Here we utilize N-bromosuccinimide (NBS) and carry out oxidative bromination on platinum(II) drugs, namely cisplatin, carboplatin, and oxaliplatin, to obtain asymmetric and mono-bromo platinum(IV) prodrugs. Different solvents are used to obtain various compounds, and the compounds are further functionalized. Di-bromo compounds are also obtained through NBS-directed oxidative bromination in ethanol. The crystal structures of representative compounds are discussed, and the reduction potentials of some compounds are examined. A cytotoxicity test shows that the mono- and di-bromo platinum(IV) compounds are active against human ovarian cancer cells. Our study enriches the family of asymmetric platinum(IV) prodrugs and provides with a convenient strategy to obtain brominated platinum(IV) complexes.

  10. Measurement and human exposure assessment of brominated flame retardants in household products from South China.

    PubMed

    Chen, She-Jun; Ma, Yun-Juan; Wang, Jing; Tian, Mi; Luo, Xiao-Jun; Chen, Da; Mai, Bi-Xian

    2010-04-15

    Brominated flame retardants (BFRs), polybrominated diphenyl ethers (PBDEs), and decabromodiphenyl ethane (DBDPE) were examined in household products in the Pearl River Delta, South China, including electronic appliances, furniture and upholstery, car interiors, and raw materials for electronics. The concentrations of PBDEs derived from penta-BDE mixture were much lower (<111 ng/g) than those for octa- and deca-BDE commercially derived PBDEs, with maximum values of 15,107 and 1,603,343 ng/g, respectively, in all the household products. Our findings suggest the recycling of old electronic products and their reuse might be also a potential important source of discontinued PBDEs to the environment. DBDPE was found in 20.0% of all the samples, ranging from 311 to 268,230 ng/g. PBDE congener profiles in both the household products and raw materials suggest that some less brominated BDEs in the environment may be derived from the decomposition of higher brominated PBDEs in PBDE-containing products in process of the manufacturing, use and/or recycling. Human exposure to PBDEs from household products via inhalation ranged from 175 to 612 pg/kg bw day, accounting for a small proportion of the total daily exposure via indoor inhalation. Despite the low deleterious risk associated with household products with regard to PBDEs, they are of special concern because of the relatively higher exposures observed for young children and further work is required.

  11. Examination of the kinetics of degradation of the antineoplastic drug 5-fluorouracil by chlorine and bromine.

    PubMed

    Li, Wei; Tanumihardja, Jessica; Masuyama, Takaaki; Korshin, Gregory

    2015-01-23

    This study examined the degradation of the widely used antineoplastic drug 5-fluorouracil (5FU) by chlorine and bromine. 5FU was determined to interact readily with free chlorine and bromine but was stable in the presence of chloramine. The removal of 5FU followed a second-order kinetic pattern. Apparent rates (kapp) of 5FU removal by chlorine and bromine were strongly pH dependent and had maximum 14.8M(-1)s(-1) and 1.9×10(3)M(-1)s(-1)kapp values, respectively at pH 7. Modeling of the dependence of the kapp values vs. pH indicated the presence of a relatively acidic (pK 6.4 vs. 8.5 of 5FU per se) 5FU intermediate generated in the presence of halogen species. Spectrophotometric measurements confirmed the increased acidity of 5FU chlorination products and allowed proposing a degradation pathway of 5FU by chlorine. This pathway suggests that 5FU chlorination proceeds via chlorine incorporation at the 6th carbon in the heterocyclic ring of 5FU.

  12. Bromine incorporation into five DBP classes upon chlorination of water with extremely low SUVA values.

    PubMed

    Hong, Huachang; Yan, Xiaoqing; Song, Xuhui; Qin, Yanyan; Sun, Hongjie; Lin, Hongjun; Chen, Jianrong; Liang, Yan

    2017-07-15

    The main objective of this study was to assess the effects of disinfection conditions on bromine incorporation into disinfection by-products (DBPs) during chlorination of water with low specific UV absorbance (SUVA). Five classes of DBPs were included: trihalomethanes (THMs), dihaloacetic acids (di-HAAs), trihaloacetic acids (tri-HAAs), dihaloacetonitriles (DHANs) and trihalonitromethanes (THNMs). Results showed that the bromine utilization in DBPs formation was positive related with reaction time, pH and temperature. On the other hand, the bromine substitution factors (BSFs) of DBPs were generally increased with pH (except tri-HAAs) and bromide concentration, but decreased with the reaction time, temperature and chlorine dose. Moreover, the BSFs values varied with DBP classes with the ranking being as following: THNMs≫DHANs≫tri-HAAs>THM≈di-HAAs. These results were mostly similar with the references, yet the pH effect on BSFs as well as the rank of BSFs for different DBP classes may differ with the specific UV absorbance of organic matter.

  13. Induced production of brominated aromatic compounds in the alga Ceramium tenuicorne.

    PubMed

    Dahlgren, Elin; Enhus, Carolina; Lindqvist, Dennis; Eklund, Britta; Asplund, Lillemor

    2015-11-01

    In the Baltic Sea, high concentrations of toxic brominated aromatic compounds have been detected in all compartments of the marine food web. A growing body of evidence points towards filamentous algae as a natural producer of these chemicals. However, little is known about the effects of environmental factors and life history on algal production of brominated compounds. In this study, several congeners of methoxylated polybrominated diphenyl ethers (MeO-PBDEs), hydroxylated polybrominated diphenyl ethers (OH-PBDEs) and brominated phenols (BPs) were identified in a naturally growing filamentous red algal species (Ceramium tenuicorne) in the Baltic Sea. The identified substances displayed large seasonal variations in the alga with a concentration peak in July. Production of MeO-/OH-PBDEs and BPs by C. tenuicorne was also established in isolated clonal material grown in a controlled laboratory setting. Based on three replicates, herbivory, as well as elevated levels of light and salinity in the culture medium, significantly increased the production of 2,4,6-tribromophenol (2,4,6-TBP). Investigation of differences in production between the isomorphic female, male and diploid clonal life stages of the alga grown in the laboratory revealed a significantly higher production of 2,4,6-TBP in the brackish water female gametophytes, compared to the corresponding marine gametophytes. Even higher concentrations of 2,4,6-TBP were produced by marine male gametophytes and sporophytes.

  14. Discrimination of hexabromocyclododecane from new polymeric brominated flame retardant in polystyrene foam by nuclear magnetic resonance.

    PubMed

    Jeannerat, Damien; Pupier, Marion; Schweizer, Sébastien; Mitrev, Yavor Nikolaev; Favreau, Philippe; Kohler, Marcel

    2016-02-01

    Hexabromocyclododecane (HBCDD) is a brominated flame retardant (BFR) and major additive to polystyrene foam thermal insulation that has recently been listed as a persistent organic pollutant by the Stockholm Convention. During a 2013/2014 field analytical survey, we measured HBCDD content ranging from 0.2 to 2.4% by weight in 98 polystyrene samples. Liquid chromatography coupled to tandem mass spectrometry (LC-MS/MS) analyses indicated that expandable (EPS) and extruded (XPS) polystyrene foams significantly differed in the α/γ HBCDD isomer ratio, with a majority of α and γ isomers in XPS and EPS, respectively. Interestingly, this technique indicated that some recent materials did not contain HBCDD, but demonstrated bromine content when analysed with X-ray fluorescence (XRF). Further investigation by Nuclear Magnetic Resonance (NMR) was able to discriminate between the BFRs present. In addition to confirming the absence or presence of HBCDD in polystyrene samples, high-field NMR spectroscopy provided evidence of the use of brominated butadiene styrene (BBS) as copolymer in the production of polystyrene. Use of this alternative flame retardant is expected to cause fewer health and environmental concerns. Our results highlight a trend towards the use of copolymerized BFRs as an alternative to HBCDD in polystyrene foam boards. In addition to providing a rapid NMR method to identify polymeric BFR, our analytical approach is a simple method to discriminate between flame-retardants in polystyrene foam insulating materials.

  15. Monitoring of WEEE plastics in regards to brominated flame retardants using handheld XRF.

    PubMed

    Aldrian, Alexia; Ledersteger, Alfred; Pomberger, Roland

    2015-02-01

    This contribution is focused on the on-site determination of the bromine content in waste electrical and electronic equipment (WEEE), in particular waste plastics from television sets (TV) and personal computer monitors (PC) using a handheld X-ray fluorescence (XRF) device. The described approach allows the examination of samples in regards to the compliance with legal specifications for polybrominated biphenyls (PBBs) and polybrominated diphenyl ethers (PBDEs) directly after disassembling and facilitates the sorting out of plastics with high contents of brominated flame retardants (BFRs). In all, over 3000 pieces of black (TV) and 1600 pieces of grey (PC) plastic waste were analysed with handheld XRF technique for this study. Especially noticeable was the high percentage of pieces with a bromine content of over 50,000ppm for TV (7%) and PC (39%) waste plastics. The applied method was validated by comparing the data of handheld XRF with results obtained by GC-MS. The results showed the expected and sufficiently accurate correlation between these two methods. It is shown that handheld XRF technique is an effective tool for fast monitoring of large volumes of WEEE plastics in regards to BFRs for on-site measurements.

  16. Removal of brominated flame retardant from electrical and electronic waste plastic by solvothermal technique.

    PubMed

    Zhang, Cong-Cong; Zhang, Fu-Shen

    2012-06-30

    Brominated flame retardants (BFRs) in electrical and electronic (E&E) waste plastic are toxic, bioaccumulative and recalcitrant. In the present study, tetrabromobisphenol A (TBBPA) contained in this type of plastic was tentatively subjected to solvothermal treatment so as to obtain bromine-free plastic. Methanol, ethanol and isopropanol were examined as solvents for solvothermal treatment and it was found that methanol was the optimal solvent for TBBPA removal. The optimum temperature, time and liquid to solid ratio for solvothermal treatment to remove TBBPA were 90°C, 2h and 15:1, respectively. After the treatment with various alcohol solvents, it was found that TBBPA was finally transferred into the solvents and bromine in the extract was debrominated catalyzed by metallic copper. Bisphenol A and cuprous bromide were the main products after debromination. The morphology and FTIR properties of the plastic were generally unchanged after the solvothermal treatment indicating that the structure of the plastic maintained after the process. This work provides a clean and applicable process for BFRs-containing plastic disposal.

  17. Effects of sequential treatment with fluorine and bromine on graphite fibers

    NASA Technical Reports Server (NTRS)

    Hung, Ching-Cheh; Stahl, Mark; Maciag, Carolyn; Slabe, Melissa

    1987-01-01

    Three pitch based graphite fibers with different degrees of graphitization and one polyacryonitrile (PAN) based carbon fiber from Amoco Corporation were treated with 1 atm, room temperature fluorine gas for 90 hrs. Fluorination resulted in higher electrical conductivity for all pitch fibers. Further bromination after ambient condition defluorination resulted in further increases in electrical defluorination conductivity for less graphitized, less structurally ordered pitch fibers (P-55) which contain about 3% fluorine by weight before bromination. This product can be stable in 200 C air, or 100% humidity at 60 C. Due to its low cost, this less graphitized fiber may be useful for industrial application, such as airfoil deicer materials. The same bromination process, however, resulted in conductivity decreases for fluorine rich, more graphitized, structurally oriented pitch fibers (P-100 and P-75). Such decreases in electrical conductivity were partially reversed by heating the fibers at 185 C in air. Differential scanning calorimetric (DSC) data indicated that the more graphitized fibers (P-100) contained BrF3, whereas the less graphitized fibers (P-55) did not.

  18. Effect of Bromine Substitution on Human Dermal Absorption of Polybrominated Diphenyl Ethers.

    PubMed

    Abdallah, Mohamed Abou-Elwafa; Pawar, Gopal; Harrad, Stuart

    2015-09-15

    Human dermal absorption of eight mono- to deca-brominated diphenyl ethers (PBDEs) was investigated for the first time using EPISKIN human skin equivalent tissue. Using a standard in vitro protocol, EPISKIN tissues mounted in specially designed diffusion cells were exposed to the target PBDEs for 24 h. Estimated steady-state flux (Jss) and permeation coefficients (Papp) across the skin increased with decreasing bromine substitution from BDE-153 (Papp = 4.0 × 10(-4) cm/h) to BDE-1 (Papp = 1.1 × 10(-2) cm/h). This was accompanied by an increase in the time required to traverse the skin tissue into the receptor fluid (lag time) from 0.25 h for BDE-1 to 1.26 h for BDE-153. Papp values for the studied PBDEs were correlated significantly (P < 0.05) with physicochemical parameters like water solubility and log KOW. While less brominated congeners achieved faster dermal penetration, higher PBDEs displayed greater accumulation within the skin tissue. The PBDEs thus accumulated represent a contaminant depot from which they may be slowly released to the systemic circulation over a prolonged period. Maximal percutaneous penetration was observed for BDE-1 (∼ 30% of the applied 500 ng/cm(2) dose). Interestingly, BDE-183 and BDE-209 showed very low dermal absorption, exemplified by a failure to reach the steady state within the 24 h exposure period that was studied.

  19. Freeze-induced formation of bromine/chlorine interhalogen species from aqueous halide ion solutions.

    PubMed

    O'Concubhair, Ruairí; Sodeau, John R

    2012-10-02

    Both gaseous bromine and bromine chloride have been monitored in polar environments and implicated in the destruction of tropospheric ozone. The formation mechanisms operating for these halogen compounds have been suggested previously. However, few laboratory studies have been performed using environmentally relevant concentrations of bromide and chloride ions in polar ice mimics. In aqueous solutions held at room temperature, previous studies have shown that the major product is the Cl(2)Br¯ trihalide ion when solutions of bromate, hydrochloric acid, and bromide ions are left to equilibrate. In contrast, the results of the cryochemical experiments presented here suggest that the dibromochloride ion (BrBrCl¯) is the major product when solutions of bromate, sulfuric acid, bromide, and chloride ions are frozen. Such a species would preferentially release bromine to the gas phase. Hence, similar halide starting materials form structurally different trihalide ions when frozen, which are capable of releasing differing active halogens, BrCl and Br(2), to the gas-phase. This is a potentially important finding because Br(2) is photolyzed more readily and to longer wavelengths than BrCl and therefore the efficiency in forming products that can lead to ozone destruction in the atmosphere would be increased. Evidence is provided for the mechanism to occur by means of both the freeze-concentration effect and the incorporation of ions into the growing ice phase.

  20. High Performance Hydrogen/Bromine Redox Flow Battery for Grid-Scale Energy Storage

    SciTech Connect

    Cho, KT; Ridgway, P; Weber, AZ; Haussener, S; Battaglia, V; Srinivasan, V

    2012-01-01

    The electrochemical behavior of a promising hydrogen/bromine redox flow battery is investigated for grid-scale energy-storage application with some of the best redox-flow-battery performance results to date, including a peak power of 1.4 W/cm(2) and a 91% voltaic efficiency at 0.4 W/cm(2) constant-power operation. The kinetics of bromine on various materials is discussed, with both rotating-disk-electrode and cell studies demonstrating that a carbon porous electrode for the bromine reaction can conduct platinum-comparable performance as long as sufficient surface area is realized. The effect of flow-cell designs and operating temperature is examined, and ohmic and mass-transfer losses are decreased by utilizing a flow-through electrode design and increasing cell temperature. Charge/discharge and discharge-rate tests also reveal that this system has highly reversible behavior and good rate capability. (C) 2012 The Electrochemical Society. [DOI: 10.1149/2.018211jes] All rights reserved.

  1. Contribution of synthetic and naturally occurring organobromine compounds to bromine mass in marine organisms.

    PubMed

    Wan, Yi; Jones, Paul D; Wiseman, Steve; Chang, Hong; Chorney, Dave; Kannan, Kurunthachalam; Zhang, Kun; Hu, Jian-Ying; Khim, Jong Seong; Tanabe, Shinsuke; Lam, Michael H W; Giesy, John P

    2010-08-15

    An extraction, separation, and purification method was developed for the identification and quantification of total bromine (TBr), extractable organobromine (EOBr), and five classes of identified EOBrs. Instrumental neutron activation analysis (INAA) was utilized to quantify EOBr and TBr. The method was then applied to liver samples of tuna, albatross, and polar bear collected from remote marine locations. Polybrominated biphenyls (PBBs), polybrominated diphenyl ethers (PBDEs), bromophenols (BRPs), hydroxylated (OH-) and methoxylated (MeO-) PBDEs were analyzed as identified EOBr. The majority of the bromine in these marine organisms was nonextractable or inorganic, with EOBr accounting for 10-28% of the TBr. Of the identified EOBr, in tuna and albatross, naturally occurring compounds, including MeO-PBDEs, OH-PBDEs, and BPRs, were prevalent. However, the identifiable EOBr in polar bears consisted primarily of synthetic compounds, including PBDEs and PBBs. Overall, 0.08-0.11% and 0.008-0.012% of EOBr and TBr, respectively, were identified. The proportion of EOBr that was identified in marine organisms was relatively small compared to the proportions for organofluorine and organochlorine compounds. This could be related to the great diversity of naturally occurring organobromine compounds in the environment. Naturally occurring brominated fatty acids were estimated to be the predominant compounds in the EOBr fraction.

  2. Functionalized Poly(3-hexylthiophene)s via Lithium–Bromine Exchange

    PubMed Central

    2015-01-01

    Poly(3-hexylthiophene) (P3HT) is one of the most extensively investigated conjugated polymers and has been employed as the active material in many devices including field-effect transistors, organic photovoltaics and sensors. As a result, methods to further tune the properties of P3HT are desirable for specific applications. Herein, we report a facile postpolymerization modification strategy to functionalize the 4-position of commercially available P3HT in two simple steps–bromination of the 4-position of P3HT (Br–P3HT) followed by lithium−bromine exchange and quenching with an electrophile. We achieved near quantitative lithium–bromine exchange with Br–P3HT, which requires over 100 thienyl lithiates to be present on a single polymer chain. The lithiated-P3HT is readily combined with functional electrophiles, resulting in P3HT derivatives with ketones, secondary alcohols, trimethylsilyl (TMS) group, fluorine, or an azide at the 4-position. We demonstrated that the azide-modified P3HT could undergo Cu-catalyzed or Cu-free click chemistry, significantly expanding the complexity of the structures that can be appended to P3HT using this method. PMID:25620811

  3. Mechanochemical conversion of brominated POPs into useful oxybromides: a greener approach

    PubMed Central

    Cagnetta, Giovanni; Liu, Han; Zhang, Kunlun; Huang, Jun; Wang, Bin; Deng, Shubo; Wang, Yujue; Yu, Gang

    2016-01-01

    Brominated organic pollutants are considered of great concern for their adverse effect on human health and the environment, so an increasing number of such compounds are being classified as persistent organic pollutants (POPs). Mechanochemical destruction is a promising technology for POPs safe disposal because it can achieve their complete carbonization by solvent-free high energy ball milling at room temperature. However, a large amount of co-milling reagent usually is necessary, so a considerable volume of residue is produced. In the present study a different approach to POPs mechanochemical destruction is proposed. Employing stoichiometric quantities of Bi2O3 or La2O3 as co-milling reagent, brominated POPs are selectively and completely converted into their corresponding oxybromides (i.e. BiOBr and LaOBr), which possess very peculiar properties and can be used for some actual and many more potential applications. In this way, bromine is beneficially reused in the final product, while POPs carbon skeleton is safely destroyed to amorphous carbon. Moreover, mechanochemical destruction is employed in a greener and more sustainable manner. PMID:27325373

  4. Brominating activity of the seaweed Ascophyllum nodosum: Impact on the biosphere

    SciTech Connect

    Wever, R.; Tromp, M.G.M.; Krenn, B.E.; Marjani, A.; Van Tol, M. )

    1991-03-01

    Macroalgae are an important source of volatile halogenated organic compounds, such as bromoform and dibromomethane. The mechanism by which these compounds are formed is still elusive. The authors report that the brown seaweeds Laminaria saccharina, Laminaria digitata, Fucus vesiculosis, Pelvetia canaliculata, and Ascophyllum nodosum and the red seaweeds Chondrus crispus and Plocamium hamatum contain bromoperoxidases. The intact plants are able to brominate exogeneous organic compounds when H{sub 2}O{sub 2} and Br{sup {minus}} are added to seawater. Further, the authors show that the brominating activity of the brown macroalga A. nodosum, which contains a vanadium bromoperoxidase located on the thallus surface, occurs when the plant is exposed to light and not in the dark. The rate of bromination of exogenous organic compounds in seawater by this plant is 68 nmol (g of wet alga){sup {minus}1} h{sup {minus}1}. HOBr is a strong biocidal agent and the authors propose that the formation of HOBr by this seaweed is part of a host defense system.

  5. A satellite based study of tropospheric bromine explosion events and their linkages to polar cyclone development

    NASA Astrophysics Data System (ADS)

    Blechschmidt, Anne-Marlene; Richter, Andreas; Burrows, John P.; Kaleschke, Lars; Strong, Kimberly; Theys, Nicolas; Weber, Mark; Zhao, Xiaoyi; Zien, Achim; Hodges, Kevin I.

    2016-04-01

    Intense, cyclone-like shaped plumes of tropospheric bromine monoxide (BrO) are regularly observed by the UV-vis satellite instruments GOME-2/MetOp-A and SCIAMACHY/Envisat over Arctic and Antarctic sea ice in polar spring. The plumes are associated with an autocatalytic chemical chain reaction involving tropospheric ozone depletion and initiated by the release of bromine from cold brine-covered ice or snow to the atmosphere. This influences atmospheric chemistry as it affects the oxidising capacity of the troposphere through OH production and may also influence the local weather/temperature of the polar atmosphere, as ozone is a major greenhouse gas. Here, we make combined use of satellite retrievals and numerical model simulations to study individual BrO plume cases in the polar atmosphere. In agreement with previous studies, our analysis shows that the plumes are often transported by high latitude cyclones, sometimes over several days despite the short atmospheric lifetime of BrO. Moreover, general characteristics of bromine explosion events linked to transport by polar weather systems, such as frequency, spatial distribution and favourable weather conditions are derived based on a new detection method. Our results show that BrO cyclone transport events are by far more common in the Antarctic than in the Arctic.

  6. Polyfunctional epoxies. I - Rubber-toughened brominated and nonbrominated formulations for graphite composites. II - Nonrubber versus rubber-toughened brominated formulations for graphite composites

    NASA Technical Reports Server (NTRS)

    Nir, Z.; Gilwee, W. J.; Kourtides, D. A.; Parker, J. A.

    1985-01-01

    A new trifunctional epoxy resin, Tris-(hydroxyphenyl) methane triglycidyl ether, is compared to a state-of-the-art tetraglycidyl 4,4'-diaminodiphenyl methane (TGDDM), in graphite composites. Rubber-toughened brominated formulations of the epoxy resin are compared to nonbrominated ones in terms of their mechanical performance, environmental stability, thermochemical behavior, and flame retardancy. It is shown that the new resin performs almost the same way as the TGDDM does, but has improved glass transition temperature and environmental properties. Brominated polymeric additives (BPA) of different molecular weights are tested as a Br source to flame retardant graphite epoxy composites. The optimal molecular weight of the BPA and its polymeric backbone length are derived and compared with a 10 percent rubber-toughened formulation of the epoxy resin. Results indicate that when the Br content in the graphite composite is increased without the use of rubber, the mechanical properties improved. The use of BPAs as tougheners for graphite composites is also considered.

  7. METHOD OF ISOTOPE CONCENTRATION

    DOEpatents

    Spevack, J.S.

    1957-04-01

    An isotope concentration process is described which consists of exchanging, at two or more different temperature stages, two isotopes of an element between substances that are physically separate from each other and each of which is capable of containing either of the isotopes, and withdrawing from a point between at least two of the temperatare stages one of the substances containing an increased concentration of the desired isotope.

  8. Cosmic ray isotopes

    NASA Technical Reports Server (NTRS)

    Stone, E. C.

    1973-01-01

    The isotopic composition of cosmic rays is studied in order to develop the relationship between cosmic rays and stellar processes. Cross section and model calculations are reported on isotopes of H, He, Be, Al and Fe. Satellite instrument measuring techniques separate only the isotopes of the lighter elements.

  9. Isotope reference materials

    USGS Publications Warehouse

    Coplen, Tyler B.

    2010-01-01

    Measurement of the same isotopically homogeneous sample by any laboratory worldwide should yield the same isotopic composition within analytical uncertainty. International distribution of light element isotopic reference materials by the International Atomic Energy Agency and the U.S. National Institute of Standards and Technology enable laboratories to achieve this goal.

  10. Statistical clumped isotope signatures

    PubMed Central

    Röckmann, T.; Popa, M. E.; Krol, M. C.; Hofmann, M. E. G.

    2016-01-01

    High precision measurements of molecules containing more than one heavy isotope may provide novel constraints on element cycles in nature. These so-called clumped isotope signatures are reported relative to the random (stochastic) distribution of heavy isotopes over all available isotopocules of a molecule, which is the conventional reference. When multiple indistinguishable atoms of the same element are present in a molecule, this reference is calculated from the bulk (≈average) isotopic composition of the involved atoms. We show here that this referencing convention leads to apparent negative clumped isotope anomalies (anti-clumping) when the indistinguishable atoms originate from isotopically different populations. Such statistical clumped isotope anomalies must occur in any system where two or more indistinguishable atoms of the same element, but with different isotopic composition, combine in a molecule. The size of the anti-clumping signal is closely related to the difference of the initial isotope ratios of the indistinguishable atoms that have combined. Therefore, a measured statistical clumped isotope anomaly, relative to an expected (e.g. thermodynamical) clumped isotope composition, may allow assessment of the heterogeneity of the isotopic pools of atoms that are the substrate for formation of molecules. PMID:27535168

  11. Bromine monoxide / sulphur dioxide ratios in relation to volcanological observations at Mt. Etna 2006-2009

    NASA Astrophysics Data System (ADS)

    Bobrowski, N.; Giuffrida, G.

    2012-12-01

    Over a 3-yr period, from 2006 to 2009, frequent scattered sunlight DOAS measurements were conducted at Mt. Etna at a distance of around 6 km downwind from the summit craters. During the same period and in addition to these measurements, volcanic observations were made by regularly visiting various parts of Mt. Etna. Here, results from these measurements and observations are presented and their relation is discussed. The focus of the investigation is the bromine monoxide/sulphur dioxide (BrO / SO2) ratio, and its variability in relation to volcanic processes. That the halogen/sulphur ratio can serve as a precursor or indicator for the onset of eruptive activity was already proposed by earlier works (e.g. Noguchi and Kamiya 1963; Menyailov, 1975; Pennisi and Cloarec, 1998; Aiuppa et al., 2002). However, there is still a limited understanding today because of the complexity with which halogens are released, depending on magma composition and degassing conditions. Our understanding of these processes is far from complete, for example of the rate and mechanism of bubble nucleation, growth and ascent in silicate melts (Carroll and Holloway, 1994), the halogen vapour-melt partitioning and the volatile diffusivity in the melt (Aiuppa et al., 2009). With this study we aim to add one more piece to the puzzle of what halogen/sulphur ratios might tell about volcanic activities. Our data set shows an increase of the BrO / SO2 ratio several weeks prior to an eruption, followed by a decline before and during the initial phase of eruptive activities. Towards the end of activity or shortly thereafter, the ratio increases to baseline values again and remains more or less constant during quiet phases. To explain the observed evolution of the BrO / SO2 ratio, a first empirical model is proposed. This model suggests that bromine, unlike chlorine and fluorine, is less soluble in the magmatic melt than sulphur. By using the DOAS method to determine SO2, we actually observe most of the

  12. Bromination of aromatic compounds by residual bromide in sodium chloride matrix modifier salt during heated headspace GC/MS analysis.

    PubMed

    Fine, Dennis D; Ko, Saebom; Huling, Scott

    2013-12-15

    Analytical artifacts attributed to the bromination of toluene, xylenes, and trimethylbenzenes were found during the heated headspace gas chromatography/mass spectrometry (GC/MS) analysis of aqueous samples. The aqueous samples were produced from Fenton-like chemical oxidation reactions and contained aromatic compounds, hydrogen peroxide (H2O2), and ferric sulfate. Prior to GC/MS headspace analysis, the samples were acidified (pH<2), and sodium chloride was amended to the headspace vial as a matrix modifier. The brominated artifacts were generated during heated headspace analysis. Further, when samples were spiked with a mixture of volatile chlorinated and aromatic compounds (50 µg/L), poor spike recoveries of toluene and xylenes occurred, and in some cases complete loss of trimethylbenzenes and naphthalene resulted. Where poor recovery of aromatic spike compounds occurred, brominated aromatic compounds were found. The only significant source of bromine in the reaction scheme is the bromide typically present (<0.01% w/w) in the sodium chloride amended to the samples. Conversely, brominated artifacts were absent when a buffered salt mixture composed of sodium chloride and potassium phosphate dibasic/monobasic was used as a matrix modifier and raised the sample pH (pH~6). This indicated that the brominated artifacts resulted from the reaction of the aromatic compounds with BrCl, which was formed by the reaction of H2O2, chloride, and bromide under acidic conditions. An alternative matrix modifier salt is recommended that prevents the bromination reaction and avoids these deleterious effects on sample integrity during headspace analysis.

  13. Generation of Radixenon Isotopes

    SciTech Connect

    McIntyre, Justin I.; Bowyer, Ted W.; Hayes, James C.; Heimbigner, Tom R.; Morris, Scott J.; Panisko, Mark E.; Pitts, W. K.; Pratt, Sharon L.; Reeder, Paul L.; Thomas, Charles W.

    2003-06-30

    Pacific Northwest National Laboratory has developed an automated system for separating Xe from air and can detect the following radioxenon isotopes, 131mXe, 133mXe, 133Xe, and 135Xe. This report details the techniques used to generate the various radioxenon isotopes that are used for the calibration of the detector as well as other isotopes that have the potential to interfere with the fission produced radioxenon isotopes. Fission production is covered first using highly enriched uranium followed by a description and results from an experiment to produce radioxenon isotopes from neutron activation of ambient xenon.

  14. ISOTOPE CONVERSION DEVICE

    DOEpatents

    Wigner, E.P.; Young, G.J.; Ohlinger, L.A.

    1957-12-01

    This patent relates to nuclear reactors of tbe type utilizing a liquid fuel and designed to convert a non-thermally fissionable isotope to a thermally fissionable isotope by neutron absorption. A tank containing a reactive composition of a thermally fissionable isotope dispersed in a liquid moderator is disposed within an outer tank containing a slurry of a non-thermally fissionable isotope convertible to a thermally fissionable isotope by neutron absorption. A control rod is used to control the chain reaction in the reactive composition and means are provided for circulating and cooling the reactive composition and slurry in separate circuits.

  15. Tryptophan octyl ester in detergent micelles of dodecylmaltoside: fluorescence properties and quenching by brominated detergent analogs.

    PubMed Central

    de Foresta, B; Gallay, J; Sopkova, J; Champeil, P; Vincent, M

    1999-01-01

    The fluorescence properties of tryptophan octyl ester (TOE), a hydrophobic model of Trp in proteins, were investigated in various mixed micelles of dodecylmaltoside (DM) and 7,8-dibromododecyl beta-maltoside (BrDM) or 10,11-dibromoundecanoyl beta-maltoside (BrUM). This study focuses on the mechanism via which these brominated detergents quench the fluorescence of TOE in a micellar system. The experiments were performed at a pH at which TOE is uncharged and almost completely bound to detergent micelles. TOE binding was monitored by its enhanced fluorescence in pure DM micelles or its quenched fluorescence in pure BrUM or BrDM micelles. In DM/BrUM and DM/BrDM mixed micelles, the fluorescence intensity of TOE decreased, as a nonlinear function of the molar fraction of brominated detergent, to almost zero in pure brominated detergent. The indole moiety of TOE is therefore highly accessible to the bromine atoms located on the detergent alkyl chain because quenching by bromines occurs by direct contact with the fluorophore. TOE is simultaneously poorly accessible to iodide (I(-)), a water-soluble collisional quencher. TOE time-resolved fluorescence intensity decay is heterogeneous in pure DM micelles, with four lifetimes (from 0.2 to 4.4 ns) at the maximum emission wavelength. Such heterogeneity may arise from dipolar relaxation processes in a motionally restricted medium, as suggested by the time-dependent (nanoseconds) red shift (11 nm) of the TOE emission spectrum, and from the existence of various TOE conformations. Time-resolved quenching experiments for TOE in mixed micelles showed that the excited-state lifetime values decreased only slightly with increases in the proportion of BrDM or BrUM. In contrast, the relative amplitude of the component with the longest lifetime decreased significantly relative to that of the short-lived species. This is consistent with a mainly static mechanism for the quenching of TOE by brominated detergents. Molecular modeling of TOE

  16. Kinetics of the Reactions of Bromine Monoxide Radicals with Chlorine Monoxide and Bromine Monoxide, and the Chemiluminescent Reactions of Fluorine with Dimethyl Sulfide

    NASA Astrophysics Data System (ADS)

    Turnipseed, Andrew Allen

    1990-01-01

    The chemistry of BrO radicals has been investigated using the technique of discharge flow coupled to mass spectrometry. BrO radicals play an important role in bromine chemistry of the stratosphere where they are predicted to be one of the most predominant forms of bromine. The reactions of BrO + BrO and Bro + ClO are rate determining steps in two catalytic destruction cycles for ozone which do not involve O atoms and should be important in the lower stratosphere and in the recently discovered ozone "hole" in Antarctica. Up to 25% of the ozone depletion is thought to occur through the coupling of bromine and chlorine chemistry in the BrO + ClO reaction. The present study has investigated the reaction of BrO + BrO over the temperature range of 253-400 K and found that the rate coefficient can be fit with the Arrhenius expression k_7(T) = (1.06 +/- 0.20) times 10 ^{-12} exp((251 +/- 56)/T) cm^3 molec ^{-1} s^{-1 }. The reaction exhibits a small negative temperature dependence and is in good agreement with past measurements. Furthermore the branching ratio into the channel forming Br_2 has been measured to be 0.12 +/- 0.04 at room temperature. The rate coefficient for the BrO + ClO reaction has been found to fit the Arrhenius expression k_5(T) = (2.59 +/- 0.36) times 10^{-12} exp((445 +/- 50)/T) cm^3 molec^{-1} s^ {-1} over the temperature range 234-408 K. Three product channels have been identified and quantified: (a) ClOO + Br, (b) OClO + Br, and (c) BrCl + O _2 as a function of temperature. These measurements have shown that the BrO + ClO reaction does proceed at a fast enough rate at low temperatures to be a major factor in ozone destruction in the polar stratosphere. A third study completed was of the reaction of F_2 + dimethyl sulfide which produces intense chemiluminescence. This reaction was undertaken in order to understand the workings of the F_2 -induced chemiluminescence detector for gas chromatography developed in our laboratory. It was found that this

  17. A Benchmark Study of Kinetic Isotope Effects and Barrier Heights for the Finkelstein Reaction.

    PubMed

    Żaczek, Szymon; Gelman, Faina; Dybala-Defratyka, Agnieszka

    2017-03-30

    Herein, we present a combined (experimental and computational) study of the Finkelstein reaction in condensed phase, where bromine is substituted by iodine in 2-bromoethylbenzene, in the presence of either acetone or acetonitrile as a solvent. Performance of various density functional theory and ab initio methods were tested for reaction barrier heights as well as for bromine and carbon kinetic isotope effects (KIEs). Two different implicit solvation models were examined (PCM and SMD). Theoretically predicted KIEs were compared with experimental values, while reaction barrier heights were assessed using the CCSD(T)-level and experimental energies as reference. In general, although the tested parameters (energies and KIEs) do not exhibit any substantial difference upon a change of the solvent, the different behavior of the theoretical methods was observed depending on the solvent. With respect to isotope effects, both PCM and SMD seem to perform very similarly, though results obtained with PCM are slightly closer to the experimental values. For predicting reaction barriers, utilization of either PCM or SMD solvation models yielded different results. Functionals from the ωB97 family: ωB97, ωB97X, and ωB97X-D provide the most accurate results for the studied system.

  18. Photochemistry of tetra- through hexa-brominated dioxins/furans, hydroxylated and native BDEs in different media.

    PubMed

    Roszko, Marek; Szymczyk, Krystyna; Jędrzejczak, Renata

    2015-12-01

    The aim of this study was to investigate (i) the behavior of native PBDEs during UV irradiation in different media, (ii) the possibility of their transformation into hydroxylated PBDEs in aqueous media, and (iii) the photochemistry/levels of brominated dioxins/furans formed from hydroxylated PBDEs. Debromination leading to the formation of a wide range of low-brominated congeners was the main path of photocatalyzed transformations of PBDEs. In organic solvents other than toluene, BDEs degraded in line with the pseudo first order kinetics (10-20 min half-life, depending on congener type and reaction medium). Irradiated BDE 209 congener behaved quite differently than lower-brominated BDEs: detectable amounts of various bromo-benzenes were found. That suggests that UV irradiation of BDE 209 leads to cleavage of the ether bound between the congener's aromatic rings. Formation of bromophenyl bromo-methyl-biphenyl ethers or benzyl-bromophenoxybenzenes was observed in irradiated PBDE toluene-based solutions. The total concentration of OH-BDEs found in the reaction medium did not exceed 0.2% of the initial precursor mass. Moreover, lower-brominated congeners detected in the reaction medium indicate subsequent debromination of OH-BDEs or hydro-debromination of the degraded congeners. Brominated dioxins and low levels of furans were observed in samples containing OH-BDEs. The total mass of dioxins did not exceed 3.5% of the initial precursor mass.

  19. S-oxygenation of thiocarbamides IV: Kinetics of oxidation of tetramethylthiourea by aqueous bromine and acidic bromate.

    PubMed

    Ajibola, Risikat O; Simoyi, Reuben H

    2011-04-07

    The kinetics and mechanism of oxidation of tetramethylthiourea (TTTU) by bromine and acidic bromate has been studied in aqueous media. The kinetics of reaction of bromate with TTTU was characterized by an induction period followed by formation of bromine. The reaction stoichiometry was determined to be 4BrO(3)(-) + 3(R)(2)C═S + 3H(2)O → 4Br(-) + 3(R)(2)C═O + 3SO(4)(2-) + 6H(+). For the reaction of TTTU with bromine, a 4:1 stoichiometric ratio of bromine to TTTU was obtained with 4Br(2) + (R)(2)C═S + 5H(2)O → 8Br(-) + SO(4)(2-) + (R)(2)C═O + 10H(+). The oxidation pathway went through the formation of tetramethythiourea sulfenic acid as evidenced by the electrospray ionization mass spectrum of the dynamic reaction solution. This S-oxide was then oxidized to produce tetramethylurea and sulfate as final products of reaction. There was no evidence for the formation of the sulfinic and sulfonic acids in the oxidation pathway. This implicates the sulfoxylate anion as a precursor to formation of sulfate. In aerobic conditions, this anion can unleash a series of genotoxic reactive oxygen species which can explain TTTU's observed toxicity. A bimolecular rate constant of 5.33 ± 0.32 M(-1) s(-1) for the direct reaction of TTTU with bromine was obtained.

  20. SIMSISH Technique Does Not Alter the Apparent Isotopic Composition of Bacterial Cells

    PubMed Central

    Chapleur, Olivier; Wu, Ting-Di; Guerquin-Kern, Jean-Luc; Mazéas, Laurent; Bouchez, Théodore

    2013-01-01

    In order to identify the function of uncultured microorganisms in their environment, the SIMSISH method, combining in situ hybridization (ISH) and nanoscale secondary ion mass spectrometry (nanoSIMS) imaging, has been proposed to determine the quantitative uptake of specific labelled substrates by uncultured microbes at the single cell level. This technique requires the hybridization of rRNA targeted halogenated DNA probes on fixed and permeabilized microorganisms. Exogenous atoms are introduced into cells and endogenous atoms removed during the experimental procedures. Consequently differences between the original and the apparent isotopic composition of cells may occur. In the present study, the influence of the experimental procedures of SIMSISH on the isotopic composition of carbon in E. coli cells was evaluated with nanoSIMS and compared to elemental analyser-isotopic ratio mass spectrometer (EA-IRMS) measurements. Our results show that fixation and hybridization have a very limited, reproducible and homogeneous influence on the isotopic composition of cells. Thereby, the SIMSISH procedure minimizes the contamination of the sample by exogenous atoms, thus providing a means to detect the phylogenetic identity and to measure precisely the carbon isotopic composition at the single cell level. This technique was successfully applied to a complex sample with double bromine – iodine labelling targeting a large group of bacteria and a specific archaea to evaluate their specific 13C uptake during labelled methanol anaerobic degradation. PMID:24204855

  1. Toxicity comparison of chlorinated and brominated dibenzo-p-dioxins and dibenzofurans in industrial source samples by HRGC/HRMS and enzyme immunoassay

    EPA Science Inventory

    Limited information is available on the applicability of polychlorinated dibenzo-p-dioxin/furan (PCDD/F) toxicity assays to their brominated counterparts: polybrominated dibenzo-p-dixoins/furans (PBDDs/Fs). We estimated the toxicity of mixtures of chlorinated, brominated, and mi...

  2. Assessment of PCDD/F and PBDD/F Emissions from Coal-fired Power Plants during Injection of Brominated Activated Carbon for Mercury Control

    EPA Science Inventory

    The effect of the injection of brominated powdered activated carbon (Br-PAC) on the emission of brominated and chlorinated dioxins and furans in coal combustion flue gas has been evaluated. The tests were performed at two U.S. Department of Energy (DOE) demonstration sites where ...

  3. Production of HBR from bromine and steam for off-peak electrolytic hydrogen generation

    SciTech Connect

    Schlief, R.E.; Hanrahan, R.J.; Stoy, M.A.

    1995-09-01

    Progress is reported on the development of a renewable energy source based solar-electrolytic system for production of hydrogen and oxygen. It employs water, bromine, solar energy and supplemental electrical power. The concept is being developed by Solar Reactor Technologies, Inc., (SRT), with the U.S. Department of Energy (DOE). An overview of the nature and objectives of this program is provided here, and technical progress made during the first (three-month) performance period of the Phase I work effort is reported. The SRT concept entails (1) absorption of concentrated solar radiation by bromine vapor Br{sub 2(g)} in a high-temperature reactor producing Br{sub (g)} atoms, (2) reaction of Br{sub (g)} with water yielding hydrogen bromide (HBr), and (3) electrolysis of stored hydrogen bromide for production of H{sub 2(g)} and recovery of Br{sub 2(I)}. Incorporation of solar radiation in the primary photochemical step (1) reduces by 50 - 70% the electrical power required to split water. The SRT concept is very attractive from an economic viewpoint as well. The reversible fuel cell, employed in the SRT electrolysis concept is capitalized via its use in load leveling by the utility. A 1 kW solar reactor was designed and constructed during the first three-month performance period by SRT personnel at the University of Florida, Gainesville. It was employed in taking survey data of the reaction between bromine and steam at temperatures between 900 and 1300 K. This reaction was run under purely thermal conditions, i.e. in the absence of solar photons. The experimental data are reported and interpreted employing concomitant thermodynamic calculations. The anticipated improvement is discussed briefly as well as the effect of a photochemical boost to the reaction. The amount of this enhancement will be studied in the next three month performance period.

  4. Seasonal variation of tropospheric bromine monoxide over the Rann of Kutch salt marsh seen from space

    NASA Astrophysics Data System (ADS)

    Hörmann, Christoph; Sihler, Holger; Beirle, Steffen; Penning de Vries, Marloes; Platt, Ulrich; Wagner, Thomas

    2016-10-01

    The Rann of Kutch (India and Pakistan) is one of the largest salt deserts in the world. Being a so-called "seasonal salt marsh", it is regularly flooded during the Indian summer monsoon. We present 10 years of bromine monoxide (BrO) satellite observations by the Ozone Monitoring Instrument (OMI) over the Great and Little Rann of Kutch. OMI spectra were analysed using Differential Optical Absorption Spectroscopy (DOAS) and revealed recurring high BrO vertical column densities (VCDs) of up to 1.4 × 1014 molec cm-2 during April/May, but no significantly enhanced column densities during the monsoon season (June-September). In the following winter months, the BrO VCDs are again slightly enhanced while the salty surface dries up. We investigate a possible correlation of enhanced reactive bromine concentrations with different meteorological parameters and find a strong relationship between incident UV radiation and the total BrO abundance. In contrast, the second Global Ozone Monitoring Instrument (GOME-2) shows about 4 times lower BrO VCDs over the Rann of Kutch than found by OMI and no clear seasonal cycle is observed. One reason for this finding might be the earlier local overpass time of GOME-2 compared to OMI (around 09:30 vs. 13:30 LT), as the ambient conditions significantly differ for both satellite instruments at the time of the measurements. Further possible reasons are discussed and mainly attributed to instrumental issues. OMI additionally confirms the presence of enhanced BrO concentrations over the Dead Sea valley (Israel/Jordan), as suggested by former ground-based observations. The measurements indicate that the Rann of Kutch salt marsh is probably one of the strongest natural point sources of reactive bromine compounds outside the polar regions and is therefore supposed to have a significant impact on local and regional ozone chemistry.

  5. Dynamical interrogation of the hydration cage of bromine in single crystal clathrate hydrates versus water.

    PubMed

    Goldschleger, I U; Kerenskaya, G; Senekerimyan, V; Janda, K C; Apkarian, V A

    2008-12-28

    We report transient grating measurements carried out on single crystals of bromine clathrate hydrates and on bromine dissolved in water. In all cases, excitation into the B-state of Br2 leads to prompt predissociation, followed by cage-induced recombination on the A/A' electronic surfaces. In liquid water, the vibrationally incoherent recombinant population peaks at t=1 ps and decays with a time constant of 1.8 ps. In the hydrate crystals, the recombination is sufficiently impulsive to manifest coherent oscillations of the reformed bond. In tetragonal TS-I crystals, with the smaller cages, the recombination is fast, t=360 fs, and the bond oscillation period is 240 fs. In cubic CS-II crystals, the recombination is slower, t=490 fs, and the visibility of the vibrational coherence, which shows a period of 290 fs, is significantly reduced due to the larger cages and the looser fit around bromine. The mechanical cage effect is quantified in terms of the recombination time-distribution, the first three moments of which are associated with size, structural rigidity, and anelasticity of the cage. In the crystalline cages, the distribution is symmetric about the mean: mean time tm=300 fs, 400 fs and standard deviation sigma=70 fs, 100 fs, in TS-I and CS-II, respectively. The finding is consistent with the assignment of occupied cages: principally 5(12)6(2) polyhedra in TS-I and 5(12)6(4) polyhedra in CS-II. In liquid water, with diffuse cages, the distribution characterized by tm=555 fs and sigma=400 fs, is strongly skewed (gamma1=1.88) toward delayed recombination-the effective liquid phase hydration shell is larger than that in a hydrate phase, structurally disordered, and anelastic. Information about dipolar disorder, comparable in all three media, is extracted from electronic predissociation rates of the B-state, which is sensitive to the symmetry in the guest-host interaction.

  6. Distribution of copper, silver and gold during thermal treatment with brominated flame retardants.

    PubMed

    Oleszek, Sylwia; Grabda, Mariusz; Shibata, Etsuro; Nakamura, Takashi

    2013-09-01

    The growing consumption of electric and electronic equipment results in creating an increasing amount of electronic waste. The most economically and environmentally advantageous methods for the treatment and recycling of waste electric and electronic equipment (WEEE) are the thermal techniques such as direct combustion, co-combustion with plastic wastes, pyrolysis and gasification. Nowadays, this kind of waste is mainly thermally treated in incinerators (e.g. rotary kilns) to decompose the plastics present, and to concentrate metals in bottom ash. The concentrated metals (e.g. copper, precious metals) can be supplied as a secondary raw material to metal smelters, while the pyrolysis of plastics allows the recovery of fuel gases, volatilising agents and, eventually, energy. Indeed, WEEE, such as a printed circuit boards (PCBs) usually contains brominated flame retardants (BFRs). From these materials, hydrobromic acid (HBr) is formed as a product of their thermal decomposition. In the present work, the bromination was studied of copper, silver and gold by HBr, originating from BFRs, such as Tetrabromobisphenol A (TBBPA) and Tetrabromobisphenol A-Tetrabromobisophenol A diglycidyl ether (TTDE) polymer; possible volatilization of the bromides formed was monitored using a thermo-gravimetric analyzer (TGA) and a laboratory-scale furnace for treating samples of metals and BFRs under an inert atmosphere and at a wide range of temperatures. The results obtained indicate that up to about 50% of copper and silver can evolve from sample residues in the form of volatile CuBr and AgBr above 600 and 1000°C, respectively. The reactions occur in the molten resin phase simultaneously with the decomposition of the brominated resin. Gold is resistant to HBr and remains unchanged in the residue.

  7. Dynamics of brominated flame retardants removal in contaminated wastewater sewage sludge under anaerobic conditions.

    PubMed

    Stiborova, Hana; Vrkoslavova, Jana; Pulkrabova, Jana; Poustka, Jan; Hajslova, Jana; Demnerova, Katerina

    2015-11-15

    Disposal of solid waste to landfills from waste water sewage treatment plants (WWTPs) serves as a potential source of contamination by polybrominated diphenyl ethers (PBDEs) and hexabromocyclododecane (HBCD). Native microbial communities have been found to degrade a variety of xenobiotics, such as PBDEs and HBCDs. This study investigates the potential of autochthonous microflora to remove 11 PBDE congeners and HBCDs in waste water sludge under anaerobic conditions. Laboratory microcosms were constructed with sewage sludge from the WWTPs of Hradec Kralove and Brno. BDE 209 was detected as the prevailing congener in concentrations 685 and 1403 ng/g dw and the total amounts of 10 lower PBDEs (BDE 28, 47, 49, 66, 85, 99, 100, 153, 154, 183) were 605 and 205 ng/g dw in sludge from Hradec Kralove and Brno, respectively. The levels of HBCD were detected in both sludge lower than 24 ng/g dw. The experiment was carried out for 15 months. After three months of incubation, HBCD was completely degraded to below detection limits. In sewage from both WWTPs, the higher brominated DEs were removed faster than the lower brominated congeners. One exception was tri-BDE, which was degraded completely within 15 months of cultivation. A significant increase in congener tetra-BDE 49 concentrations was observed over the course of the experiment in all tested sewage. The relative distribution of individual congeners among all PBDEs changed after 15 months of the incubation in favour of lower brominated congeners. This indicates that debromination is the major mechanism of anaerobic biodegradation. Despite of the increase of BDE 49, the overall removal of all 11 PBDEs achieved the levels of 47.4 and 68.7% in samples from WWTPs Hradec Kralove and Brno, respectively.

  8. Photochemical Bromine Production from Arctic Surface Snowpacks and Resulting Chemistry Aloft (Invited)

    NASA Astrophysics Data System (ADS)

    Pratt, K.; Shepson, P. B.; von Glasow, R.; Peterson, P.; Simpson, W. R.; Pöhler, D.; General, S.; Zielcke, J.; Custard, K. D.; Douglas, T. A.; Platt, U.; Tanner, D.; Nenes, A.; Carlsen, M.; Stirm, B. H.

    2013-12-01

    Following springtime polar sunrise, ozone concentrations in the lower troposphere decline to near-zero levels. These ozone depletion events are initiated by an increase in reactive bromine levels in the atmosphere. Under these conditions, the oxidative capacity of the Arctic troposphere is altered, leading to the removal of numerous transported trace gas pollutants, including mercury. Despite our increasing understanding of the spatial variability of BrO and possible reaction pathways based on laboratory studies, important questions have remained regarding the most efficient sources of and mechanisms for Arctic halogen activation. During the March-April 2012 BRomine, Ozone, and Mercury EXperiment (BROMEX) in Barrow, Alaska, outdoor chamber experiments showed that surface snow, collected above both tundra and sea ice, efficiently produced Br2 when exposed to sunlight. Br2 production via the surface snowpack explains observations of BrO enhancements above sea ice, as well as inland tundra, as measured by aircraft-based nadir MAX-DOAS (Multi Axis-Differential Optical Absorption Spectroscopy) during BROMEX. These findings indicate that atmospherically processed snow is likely a major source of Arctic bromine release, which impacts the distribution and occurrence of ozone depletion events and BrO. To investigate the potential magnitude and significance of this light-dependent surface Br2 flux, the one-dimensional model MISTRA is utilized. Near-surface Br2 concentrations are compared to chemical ionization mass spectrometry measurements, and simulated vertical profiles of ozone and BrO are compared to aircraft observations, as well as surface-based MAX-DOAS measurements.

  9. Transformation of bromine species in TiO2 photocatalytic system.

    PubMed

    Zhang, Xiwang; Zhang, Tong; Ng, Jiawei; Pan, Jia Hong; Sun, Darren Delai

    2010-01-01

    Bromine species have six oxidation states from Br(-) to BrO(3)(-), and their transformation between each oxidation state is complex and has been a common debate topic in photocatalytic systems where oxidants (h(+) and OH.) and reducers (e(-)) coexist. In this study, the lowest oxidation state (Br(-)) and highest oxidation state (BrO(3)(-)) were used as the starting compounds in a photocatalytic reaction to investigate the transformation of bromine species. The experimental results showed that oxidation of Br(-) to BrO(3)(-) by OH. and reduction of BrO(3)(-) to Br(-) by e(-) were concurrent. However, due to a higher reaction rate for reduction of BrO(3)(-) under a pH range of 3-11, oxidation of Br(-) was totally offset and hence, only the reduction of BrO(3)(-) was observed with hydrobromous acid and hydrobromite formed as intermediates. Apart from e(-), H(2)O(2), to a certain extent, was involved in the photocatalytic reduction of BrO(3)(-). A low concentration of organic matter (3 mg/L) reacted with hydroxyl radicals to inhibit combination of holes and electrons, hence promoting photocatalytic reduction of BrO(3)(-). It is important to note that pH had an influence on the transformation of bromine species, because it affects adsorption of reactants on the photocatalyst and controls the amount of aqueous H(+) and OH(-) ions present. Photocatalytic oxidation of Br(-) became dominant under a strong acidic condition (pH 1.5) while both photocatalytic oxidation and reduction were inhibited under a strong basic condition (pH 13.5).

  10. Trophic transfer of naturally produced brominated aromatic compounds in a Baltic Sea food chain.

    PubMed

    Dahlgren, Elin; Lindqvist, Dennis; Dahlgren, Henrik; Asplund, Lillemor; Lehtilä, Kari

    2016-02-01

    Brominated aromatic compounds (BACs) are widely distributed in the marine environment. Some of these compounds are highly toxic, such as certain hydroxylated polybrominated diphenyl ethers (OH-PBDEs). In addition to anthropogenic emissions through use of BACs as e.g. flame retardants, BACs are natural products formed by marine organisms such as algae, sponges, and cyanobacteria. Little is known of the transfer of BACs from natural producers and further up in the trophic food chain. In this study it was observed that total sum of methoxylated polybrominated diphenyl ethers (MeO-PBDEs) and OH-PBDEs increased in concentration from the filamentous red alga Ceramium tenuicorne, via Gammarus sp. and three-spined stickleback (Gasterosteus aculeatus) to perch (Perca fluviatilis). The MeO-PBDEs, which were expected to bioaccumulate, increased in concentration accordingly up to perch, where the levels suddenly dropped dramatically. The opposite pattern was observed for OH-PBDEs, where the concentration exhibited a general trend of decline up the food web, but increased in perch, indicating metabolic demethylation of MeO-PBDEs. Debromination was also indicated to occur when progressing through the food chain resulting in high levels of tetra-brominated MeO-PBDE and OH-PBDE congeners in fish, while some penta- and hexa-brominated congeners were observed to be the dominant products in the alga. As it has been shown that OH-PBDEs are potent disruptors of oxidative phosphorylation and that mixtures of different congener may act synergistically in terms of this toxic mode of action, the high levels of OH-PBDEs detected in perch in this study warrants further investigation into potential effects of these compounds on Baltic wildlife, and monitoring of their levels.

  11. The role of diet on long-term concentration and pattern trends of brominated and chlorinated contaminants in western Hudson Bay polar bears, 1991-2007.

    PubMed

    McKinney, Melissa A; Stirling, Ian; Lunn, Nick J; Peacock, Elizabeth; Letcher, Robert J

    2010-11-15

    Adipose tissue was sampled from the western Hudson Bay (WHB) subpopulation of polar bears at intervals from 1991 to 2007 to examine temporal trends of PCB and OCP levels both on an individual and sum-(∑-)contaminant basis. We also determined levels and temporal trends of emerging polybrominated diphenyl ethers (PBDEs), hexabromocyclododecane (HBCD), polybrominated biphenyls (PBBs) and other current-use brominated flame retardants. Over the 17-year period, ∑DDT (and p,p'-DDE, p,p'-DDD, p,p'-DDT) decreased (-8.4%/year); α-hexachlorocyclohexane (α-HCH) decreased (-11%/year); β-HCH increased (+8.3%/year); and ∑PCB and ∑chlordane (CHL), both contaminants at highest concentrations in all years (>1ppm), showed no distinct trends even when compared to previous data for this subpopulation dating back to 1968. Some of the less persistent PCB congeners decreased significantly (-1.6%/year to -6.3%/year), whereas CB153 levels tended to increase (+3.3%/year). Parent CHLs (c-nonachlor, t-nonachlor) declined, whereas non-monotonic trends were detected for metabolites (heptachlor epoxide, oxychlordane). ∑chlorobenzene, octachlorostyrene, ∑mirex, ∑MeSO(2)-PCB and dieldrin did not significantly change. Increasing ∑PBDE levels (+13%/year) matched increases in the four consistently detected congeners, BDE47, BDE99, BDE100 and BDE153. Although no trend was observed, total-(α)-HBCD was only detected post-2000. Levels of the highest concentration brominated contaminant, BB153, showed no temporal change. As long-term ecosystem changes affecting contaminant levels may also affect contaminant patterns, we examined the influence of year (i.e., aging or "weathering" of the contaminant pattern), dietary tracers (carbon stable isotope ratios, fatty acid patterns) and biological (age/sex) group on congener/metabolite profiles. Patterns of PCBs, CHLs and PBDEs were correlated with dietary tracers and biological group, but only PCB and CHL patterns were correlated with year. DDT

  12. Mechanical and electrical properties of graphite fiber-epoxy composites made from pristine and bromine intercalated fibers

    NASA Technical Reports Server (NTRS)

    Jaworske, Donald A.; Vannucci, Raymond D.; Zinolabedini, Reza

    1987-01-01

    The mechanical and electrical properties of pristine and bromine intercalated graphite fiber-epoxy composites were compared. The two types of composite were similar in terms of tensile modulus, tensile strength, and Poisson's Ratio. However, the interlaminar shear strength of the brominated composite was 18 percent greater than its pristine counterpart. Only slight differences were observed in flexural properties. A five-fold decrease was observed in the electrical resistivity of the brominated composite parallel to the axis of the fibers, resulting in a unidirectional resistivity of about 90 microOmega/cm. Transverse resistivity was unaffected. Both types of composite were subjected to a simulated lightning strike of 10 KJ (at a peak current of 150 kA), and the composite with the intercalated graphite exhibited less damage.

  13. Hybrid isotope separation scheme

    DOEpatents

    Maya, J.

    1991-06-18

    A method is described for yielding selectively a desired enrichment in a specific isotope including the steps of inputting into a spinning chamber a gas from which a scavenger, radiating the gas with a wave length or frequency characteristic of the absorption of a particular isotope of the atomic or molecular gas, thereby inducing a photochemical reaction between the scavenger, and collecting the specific isotope-containing chemical by using a recombination surface or by a scooping apparatus. 2 figures.

  14. Hybrid isotope separation scheme

    DOEpatents

    Maya, Jakob

    1991-01-01

    A method of yielding selectively a desired enrichment in a specific isotope including the steps of inputting into a spinning chamber a gas from which a scavenger, radiating the gas with a wave length or frequency characteristic of the absorption of a particular isotope of the atomic or molecular gas, thereby inducing a photochemical reaction between the scavenger, and collecting the specific isotope-containing chemical by using a recombination surface or by a scooping apparatus.

  15. HYDROGEN ISOTOPE TARGETS

    DOEpatents

    Ashley, R.W.

    1958-08-12

    The design of targets for use in the investigation of nuclear reactions of hydrogen isotopes by bombardment with accelerated particles is described. The target con struction eomprises a backing disc of a metal selected from the group consisting of molybdenunn and tungsten, a eoating of condensed titaniunn on the dise, and a hydrogen isotope selected from the group consisting of deuterium and tritium absorbed in the coatiag. The proeess for preparing these hydrogen isotope targets is described.

  16. Theoretical performance of hydrogen-bromine rechargeable SPE fuel cell. [Solid Polymer Electrolyte

    NASA Technical Reports Server (NTRS)

    Savinell, R. F.; Fritts, S. D.

    1988-01-01

    A mathematical model was formulated to describe the performance of a hydrogen-bromine fuel cell. Porous electrode theory was applied to the carbon felt flow-by electrode and was coupled to theory describing the solid polymer electrolyte (SPE) system. Parametric studies using the numerical solution to this model were performed to determine the effect of kinetic, mass transfer, and design parameters on the performance of the fuel cell. The results indicate that the cell performance is most sensitive to the transport properties of the SPE membrane. The model was also shown to be a useful tool for scale-up studies.

  17. Package of double helical bromine chains inside single-walled carbon nanotubes

    NASA Astrophysics Data System (ADS)

    Yao, Zhen; Liu, Chun Jian; Lv, Hang; Yang, Xi Bao

    2016-10-01

    The helicity of stable double helical bromine chains inside single-walled carbon nanotubes (SWCNTs) was studied through the calculation of systematic interaction energy, using the van der Waals interaction potential. The results presented clear images of stable double helical structures inside SWCNTs. The optimal helical radius and helical angle of chain structure increase and decrease, respectively, with the increase of tube radius. The detailed analysis indicated that some metastable structures in SWCNTs may also co-exist with the optimal structures, but not within the same tubes. In addition, a detailed simulation of X-ray diffraction patterns was performed for the obtained optimal helical structures.

  18. A comparison of the virucidal properties of chlorine, chlorine dioxide, bromine chloride and iodine.

    PubMed Central

    Taylor, G. R.; Butler, M.

    1982-01-01

    Chlorine dioxide, bromine chloride and iodine were compared with chlorine as virucidal agents. Under optimal conditions all disinfectants were effective at low concentrations, but each disinfectant responded differently to acidity and alkalinity. Disinfection by chlorine was impaired by the presence of ammonia, but the other disinfectants retained much of their potency. Disinfection of poliovirus by iodine resulted in structural changes in the virions as seen by electron micrroscopy, but the other disinfectants were able to inactivate poliovirus without causing any apparent structural changes. Images Plate 1 PMID:6290566

  19. A review of mathematical modelling of the zinc/bromine flow cell and stack of cells

    NASA Astrophysics Data System (ADS)

    Evans, T. I.; White, R. E.

    Macroscopic mathematical models for investigating various aspects of the zinc/bromine cell and stack of cells are reviewed. The general material balance equation for each species, in addition to the general expressions describing both transport in a parallel plate electrochemical reactor and the electrode kinetics, are first given. Partial differential equation models predicting current and potential distributions, an algebraic model including shunt currents and associated energy losses, and ordinary differential equation models predicting energy efficiency of the cell as a function of the state-of-charge are discussed. Microscopic models which describe the initiation and subsequent growth of zinc dendrites are also considered.

  20. Alternate and new brominated flame retardants detected in U.S. house dust.

    PubMed

    Stapleton, Heather M; Allen, Joseph G; Kelly, Shannon M; Konstantinov, Alex; Klosterhaus, Susan; Watkins, Deborah; McClean, Michael D; Webster, Thomas F

    2008-09-15

    Due to the voluntary withdrawals and/or bans on the use of two polybrominated diphenyl ether (PBDE) commercial mixtures, an increasing number of alternate flame retardant chemicals are being introduced in commercial applications. To determine if these alternate BFRs are present in indoor environments, we analyzed dust samples collected from 19 homes in the greater Boston, MA area during 2006. Using pure and commercial standards we quantified the following brominated flame retardant chemicals using GC/ECNI-MS methods: hexabromocyclododecane (sigma HBCD), bis(2,4,6,-tribromphenoxy)ethane (BTBPE), decabromodiphenyl ethane (DBDPE), and the brominated components found in Firemaster 550 (FM 550): 2-ethylhexyl 2,3,4,5-tetrabromobenzoate (TBB) and (2-ethylhexyl)tetrabromophthalate (TBPH), the latter compound being a brominated analogue of di(2-ethylhexyl)phthalate (DEHP). The concentrations of all compounds were log-normally distributed and the largest range in concentrations was observed for HBCD (sum of all isomers), with concentrations ranging from <4.5 ng/g to a maximum of 130,200 ng/g with a median value of 230 ng/g. BTBPE ranged from 1.6 to 789 ng/g with a median value of 30 ng/g and DBDPE ranged from <10.0 to 11,070 ng/g with a median value of 201 ng/g. Of the FM 550 components, TBB ranged from <6.6 to 15,030 ng/g with a median value of 133 ng/g; whereas TBPH ranged from 1.5 to 10,630 ng/g with a median value of 142 ng/g. Furthermore, the ratio of TBB/TBPH present in the dust samples ranged from 0.05 to 50 (average 4.4), varying considerably from the ratio observed in the FM 550 commercial mixture (4:1 by mass), suggesting different sources with different chemical compositions, and/or differential fate and transport within the home. Analysis of paired dust samples collected from different rooms in the same home suggests HBCD, TBB, and TBPH are higher in dust from the main living area compared to dust collected in bedrooms; however, BTBPE and DBDPE levels were

  1. Sono-bromination of aromatic compounds based on the ultrasonic advanced oxidation processes.

    PubMed

    Fujita, Mitsue; Lévêque, Jean-Marc; Komatsu, Naoki; Kimura, Takahide

    2015-11-01

    A novel, mild "sono-halogenation" of various aromatic compounds with potassium halide was investigated under ultrasound in a biphasic carbon tetrachloride/water medium. The feasibility study was first undertaken with the potassium bromide and then extended to chloride and iodide analogues. This methodology could be considered as a new expansion of the ultrasonic advanced oxidation processes (UAOPs) into a synthetic aspect as the developed methodology is linked to the sonolytic disappearance of carbon tetrachloride. Advantages of the present method are not only that the manipulation of the bromination is simple and green, but also that the halogenating agents used are readily available, inexpensive, and easy-handling.

  2. Brominated flame retardants in waste electrical and electronic equipment: substance flows in a recycling plant.

    PubMed

    Morf, Leo S; Tremp, Josef; Gloor, Rolf; Huber, Yvonne; Stengele, Markus; Zennegg, Markus

    2005-11-15

    Brominated flame retardants (BFRs) are synthetic additives mainly used in electrical and electronic appliances and in construction materials. The properties of some BFRs are typical for persistent organic pollutants, and certain BFRs, in particular some polybrominated diphenyl ether (PBDE) congeners and hexabromocyclododecane (HBCD), are suspected to cause adverse health effects. Global consumption of the most demanded BFRs, i.e., penta-, octa-, and decaBDE, tetrabromobisphenol A (TBBPA), and HBCD, has doubled in the 1990s. Only limited and rather uncertain data are available regarding the occurrence of BFRs in consumer goods and waste fractions as well as regarding emissions during use and disposal. The knowledge of anthropogenic substance flows and stocks is essential for early recognition of environmental impacts and effective chemicals management. In this paper, actual levels of penta-, octa-, and decaBDE, TBBPA, and HBCD in waste electrical and electronic equipment (WEEE) as a major carrier of BFRs are presented. These BFRs have been determined in products of a modern Swiss recycling plant applying gas chromatography/electron capture detection and gas chromatography/mass spectrometry analysis. A substance flow analysis (SFA) technique has been used to characterize the flows of target substances in the recycling process from the bulk WEEE input into the output products. Average concentrations in small size WEEE, representing the relevant electric and electronic appliances in WEEE, sampled in 2003 amounted to 34 mg/kg for pentaBDE, 530 mg/kg for octaBDE, 510 mg/kg for decaBDE, 1420 mg/kg for TBBPA (as an additive), 17 mg/kg for HBCD, 5500 mg/kg for bromine, and 1700 mg/kg for antimony. In comparison to data that have been calculated by SFA for Switzerland from literature for the 1990s, these measured concentrations in small size WEEE were 7 times higher for pentaBDE, unexpectedly about 50% lower for decaBDE, and agreed fairly well for TBBPA (as an additive) and

  3. In vivo speciation studies and antioxidant properties of bromine in Laminaria digitata reinforce the significance of iodine accumulation for kelps

    PubMed Central

    Küpper, Frithjof C.; Carpenter, Lucy J.; Leblanc, Catherine; Toyama, Chiaki; Uchida, Yuka; Maskrey, Benjamin H.; Robinson, Joanne; Verhaeghe, Elodie F.; Malin, Gill; Luther, George W.; Kroneck, Peter M. H.; Kloareg, Bernard; Meyer-Klaucke, Wolfram; Muramatsu, Yasuyuki; Megson, Ian L.; Potin, Philippe; Feiters, Martin C.

    2013-01-01

    The metabolism of bromine in marine brown algae remains poorly understood. This contrasts with the recent finding that the accumulation of iodide in the brown alga Laminaria serves the provision of an inorganic antioxidant – the first case documented from a living system. The aim of this study was to use an interdisciplinary array of techniques to study the chemical speciation, transformation, and function of bromine in Laminaria and to investigate the link between bromine and iodine metabolism, in particular in the antioxidant context. First, bromine and iodine levels in different Laminaria tissues were compared by inductively coupled plasma MS. Using in vivo X-ray absorption spectroscopy, it was found that, similarly to iodine, bromine is predominantly present in this alga in the form of bromide, albeit at lower concentrations, and that it shows similar behaviour upon oxidative stress. However, from a thermodynamic and kinetic standpoint, supported by in vitro and reconstituted in vivo assays, bromide is less suitable than iodide as an antioxidant against most reactive oxygen species except superoxide, possibly explaining why kelps prefer to accumulate iodide. This constitutes the first-ever study exploring the potential antioxidant function of bromide in a living system and other potential physiological roles. Given the tissue-specific differences observed in the content and speciation of bromine, it is concluded that the bromide uptake mechanism is different from the vanadium iodoperoxidase-mediated uptake of iodide in L. digitata and that its function is likely to be complementary to the iodide antioxidant system for detoxifying superoxide. PMID:23606364

  4. In situ measurements of BrO and the photochemistry of inorganic bromine in the Arctic stratosphere

    NASA Astrophysics Data System (ADS)

    McKinney, Karena April

    Bromine plays a major role in catalytic removal of stratospheric ozone, particularly in the polar regions in winter. The total abundance of bromine species in the stratosphere, and its distribution among ozone-destroying forms, such as Br and BrO, and reservoir forms is, however, poorly understood. A lightweight, balloon-borne instrument employing chemical conversion/resonance fluorescence to measure BrO and ClO in situ was developed to help extend the existing knowledge of stratospheric bromine chemistry. A high-resolution profile of BrO was recorded up to 27 km in the Arctic vortex during a balloon flight from Kiruna, Sweden on February 3, 1995. Because the instrument launch took place before sunrise, while descent occurred near local noon, the resulting measurements provide information on the diurnal cycling of inorganic bromine species and the daytime BrO abundance. On ascent, high levels of BrO (10 ± 2 pptv) were observed at high solar zenith angles (SZA) in a region between 18 and 23 km where ClO abundances were also enhanced. Above 23 km, BrO mixing ratios observed on ascent were as low as 5 ± 1 pptv near SZA = 90o, increasing with altitude and solar zenith angle to 11 ± 1 at the ceiling altitude. On descent, the BrO mixing ratio exhibited more uniform values, 10 ± 2 pptv, with altitude. A photochemical model was used to evaluate inorganic bromine photochemistry under the measurement conditions. These studies indicate that, in the region above 23 km, ClO abundances are consistent with the presence of NO2, implying that the air parcel sampled had not recently experienced heterogeneous processing. Measured BrO diurnal behavior can be reproduced assuming photolysis of BrONO2 at sunrise, however, production of BrO from photolysis of HOBr cannot be ruled out. Between 18 and 23 km, elevated ClO abundances indicate a history of heterogeneous processing and decreased NO2. Morning abundances of BrO in this region are best explained by model calculations

  5. Selective and Efficient Generation of ortho-Brominated para-Substituted Phenols in ACS-Grade Methanol.

    PubMed

    Georgiev, David; Saes, Bartholomeus W H; Johnston, Heather J; Boys, Sarah K; Healy, Alan; Hulme, Alison N

    2016-01-13

    The mono ortho-bromination of phenolic building blocks by NBS has been achieved in short reaction times (15-20 min) using ACS-grade methanol as a solvent. The reactions can be conducted on phenol, naphthol and biphenol substrates, giving yields of >86% on gram scale. Excellent selectivity for the desired mono ortho-brominated products is achieved in the presence of 10 mol % para-TsOH, and the reaction is shown to be tolerant of a range of substituents, including CH3, F, and NHBoc.

  6. Effect of heat-treatment temperature of vapor-grown graphite fibers. I - Properties of their bromine intercalation compounds

    NASA Technical Reports Server (NTRS)

    Gaier, James R.; Hambourger, Paul D.; Slabe, Melissa E.

    1989-01-01

    Vapor-grown graphite fibers were heat treated at 2000, 2200, 2400, 2600, 2800, and 3000 C, brominated at room temperature for two days, and then characterized by X-ray diffraction analysis, differential scanning calorimetry, and resistivity measurements. Fibers greater than 13 microns in diameter had low resistivities (50 microohms or less) irrespective of the heat treatment temperature. An analysis of the results obtained suggests that resistivities below 6 microohms cannot be achieved through a further reduction in defect level unless the amount of bromine is increased.

  7. Distribution and speciation of bromine in mammalian tissue and fluids by X-ray fluorescence imaging and X-ray absorption spectroscopy.

    PubMed

    Ceko, Melanie J; Hummitzsch, Katja; Hatzirodos, Nicholas; Bonner, Wendy; James, Simon A; Kirby, Jason K; Rodgers, Raymond J; Harris, Hugh H

    2015-05-01

    Bromine is one of the most abundant and ubiquitous trace elements in the biosphere and until recently had not been shown to perform any essential biological function in animals. A recent study demonstrated that bromine is required as a cofactor for peroxidasin-catalysed formation of sulfilimine crosslinks in Drosophila. In addition, bromine dietary deficiency is lethal in Drosophila, whereas bromine replenishment restores viability. The aim of this study was to examine the distribution and speciation of bromine in mammalian tissues and fluids to provide further insights into the role and function of this element in biological systems. In this study we used X-ray fluorescence (XRF) imaging and inductively coupled plasma-mass spectrometry (ICP-MS) to examine the distribution of bromine in bovine ovarian tissue samples, follicular fluid and aortic serum, as well as human whole blood and serum and X-ray absorption spectroscopy (XAS) to identify the chemical species of bromine in a range of mammalian tissue (bovine, ovine, porcine and murine), whole blood and serum samples (bovine, ovine, porcine, murine and human), and marine samples (salmon (Salmo salar), kingfish (Seriola lalandi) and Scleractinian coral). Bromine was found to be widely distributed across all tissues and fluids examined. In the bovine ovary in particular it was more concentrated in the sub-endothelial regions of arterioles. Statistical comparison of the near-edge region of the X-ray absorption spectra with a library of bromine standards led to the conclusion that the major form of bromine in all samples analysed was bromide.

  8. Discovery of the krypton isotopes

    SciTech Connect

    Heim, M.; Fritsch, A.; Schuh, A.; Shore, A.; Thoennessen, M.

    2010-07-15

    Thirty-two krypton isotopes have been observed so far and the discovery of these isotopes is discussed here. For each isotope a brief summary of the first refereed publication, including the production and identification method, is presented.

  9. Intracellular Cadmium Isotope Fractionation

    NASA Astrophysics Data System (ADS)

    Horner, T. J.; Lee, R. B.; Henderson, G. M.; Rickaby, R. E.

    2011-12-01

    Recent stable isotope studies into the biological utilization of transition metals (e.g. Cu, Fe, Zn, Cd) suggest several stepwise cellular processes can fractionate isotopes in both culture and nature. However, the determination of fractionation factors is often unsatisfactory, as significant variability can exist - even between different organisms with the same cellular functions. Thus, it has not been possible to adequately understand the source and mechanisms of metal isotopic fractionation. In order to address this problem, we investigated the biological fractionation of Cd isotopes within genetically-modified bacteria (E. coli). There is currently only one known biological use or requirement of Cd, a Cd/Zn carbonic anhydrase (CdCA, from the marine diatom T. weissfloggii), which we introduce into the E. coli genome. We have also developed a cleaning procedure that allows for the treating of bacteria so as to study the isotopic composition of different cellular components. We find that whole cells always exhibit a preference for uptake of the lighter isotopes of Cd. Notably, whole cells appear to have a similar Cd isotopic composition regardless of the expression of CdCA within the E. coli. However, isotopic fractionation can occur within the genetically modified E. coli during Cd use, such that Cd bound in CdCA can display a distinct isotopic composition compared to the cell as a whole. Thus, the externally observed fractionation is independent of the internal uses of Cd, with the largest Cd isotope fractionation occurring during cross-membrane transport. A general implication of these experiments is that trace metal isotopic fractionation most likely reflects metal transport into biological cells (either actively or passively), rather than relating to expression of specific physiological function and genetic expression of different metalloenzymes.

  10. (Carbon isotope fractionation inplants)

    SciTech Connect

    O'Leary, M.H.

    1990-01-01

    The objectives of this research are: To develop a theoretical and experimental framework for understanding isotope fractionations in plants; and to develop methods for using this isotope fractionation for understanding the dynamics of CO{sub 2} fixation in plants. Progress is described.

  11. Small mammal populations in Maryland meadows during four years of herbicide (Brominal? ) applications

    USGS Publications Warehouse

    Clark, D.R.; Moulton, C.A.; Hines, J.E.; Hoffman, D.J.

    1996-01-01

    The herbicide Brominal? was applied at the recommended rate to one plot in each of three paired 0.6-ha plots; the other three plots were used as controls. Plots were sprayed once in the fall of 1988 and 1989 and twice in the spring of 1990 and 1991. Small mammals were trapped three times during each activity season (April?October) to obtain population estimates before and after spraying and in the spring preceding fall spraying or the fall following spring spraying. Population estimates immediately after spraying gave no evidence of direct mortality. By 1991, dicot vegetation on treated plots was suppressed and mean numbers of meadow voles (Microtus pennsylvanicus) were less than on control plots. Because meadow voles favor dicots over monocots in their diet, reduced availability of dicots may have been related to the smaller vole population estimates. Species diversity of small mammals was negatively correlated with size of vole populations, but was not different between treated and control plots. Brominal apparently induced opaque corneas in nine voles. The condition was found in two voles too small to have been conceived at the time of the last previous spray nearly 8 months earlier, suggesting exposure to residue alone.

  12. Ground state bromine atom density measurements by two-photon absorption laser-induced fluorescence

    NASA Astrophysics Data System (ADS)

    Sirse, N.; Foucher, M.; Chabert, P.; Booth, J.-P.

    2014-12-01

    Ground state bromine atom detection by two-photon absorption laser-induced fluorescence (TALIF) is demonstrated. The (4p5) {^2Po3/2} bromine atoms are excited by two-photon absorption at 252.594 nm to the (5p) {^4So3/2} state and detected by 635.25 nm fluorescence to the (5s) 4P5/2 state. The atoms are generated in a radio-frequency inductively-coupled plasma in pure HBr. The excitation laser also causes some photodissociation of HBr molecules, but this can be minimized by not focussing the laser beam, still giving adequate signal levels. We determined the natural lifetime of the emitting (5p) {^4So3/2} state, τf^Br*=30.9 +/- 1.4 ns and the rate constant for quenching of this state by collision with HBr molecules, k_HBrQ = 1.02 +/- 0.07× 10-15 m3 s-1 .

  13. Dissolution of brominated epoxy resins by dimethyl sulfoxide to separate waste printed circuit boards.

    PubMed

    Zhu, Ping; Chen, Yan; Wang, Liangyou; Qian, Guangren; Zhang, Wei Jie; Zhou, Ming; Zhou, Jin

    2013-03-19

    Improved methods are required for the recycling of waste printed circuit boards (WPCBs). In this study, WPCBs (1-1.5 cm(2)) were separated into their components using dimethyl sulfoxide (DMSO) at 60 °C for 45 min and a metallographic microscope was used to verify their delamination. An increased incubation time of 210 min yielded a complete separation of WPCBs into their components, and copper foils and glass fibers were obtained. The separation time decreased with increasing temperature. When the WPCB size was increased to 2-3 cm(2), the temperature required for complete separation increased to 90 °C. When the temperature was increased to 135 °C, liquid photo solder resists could be removed from the copper foil surfaces. The DMSO was regenerated by rotary decompression evaporation, and residues were obtained. Fourier transform infrared spectroscopy (FT-IR), thermal analysis, nuclear magnetic resonance, scanning electron microscopy, and energy-dispersive X-ray spectroscopy were used to verify that these residues were brominated epoxy resins. From FT-IR analysis after the dissolution of brominated epoxy resins in DMSO it was deduced that hydrogen bonding may play an important role in the dissolution mechanism. This novel technology offers a method for separating valuable materials and preventing environmental pollution from WPCBs.

  14. Natural solar photolysis of total organic chlorine, bromine and iodine in water.

    PubMed

    Abusallout, Ibrahim; Hua, Guanghui

    2016-04-01

    Municipal wastewater has been increasingly used to augment drinking water supplies due to the growing water scarcity. Wastewater-derived disinfection byproducts (DBPs) may negatively affect the aquatic ecosystems and human health of downstream communities during water reuse. The objective of this research was to determine the degradation kinetics of total organic chlorine (TOCl), bromine (TOBr) and iodine (TOI) in water by natural sunlight irradiation. Outdoor solar photolysis experiments were performed to investigate photolytic degradation of the total organic halogen (TOX) formed by fulvic acid and real water and wastewater samples. The results showed that TOX degradation by sunlight irradiation followed the first-order kinetics with half-lives in the range of 2.6-10.7 h for different TOX compounds produced by fulvic acid. The TOX degradation rates were generally in the order of TOI > TOBr ≅ TOCl(NH2Cl) > TOCl(Cl2). High molecular weight TOX was more susceptible to solar photolysis than corresponding low molecular weight halogenated compounds. The nitrate and sulfite induced indirect TOX photolysis rates were less than 50% of the direct photolysis rates under the conditions of this study. Fulvic acid and turbidity in water reduced TOX photodegradation. These results contribute to a better understanding of the fate of chlorinated, brominated and iodinated DBPs in surface waters.

  15. Monitoring of naturally produced brominated phenoxyphenols and phenoxyanisoles in aquatic plants from the Philippines.

    PubMed

    Haraguchi, Koichi; Kotaki, Yuichi; Relox, Juan R; Romero, Marc Lawrence J; Terada, Ryuta

    2010-12-08

    Naturally produced brominated phenoxyphenols (OH-PBDEs) and phenoxyanisoles (MeO-PBDEs) were analyzed in aquatic plants (16 genera of green, brown, and red algae and angiosperms) collected from Luzon Island, the Philippines. Two brominated phenoxyphenols, 2'-hydroxy-2,3',4,5'-tetrabromodiphenyl ether (2'-OH-BDE68) and 6-hydroxy-2,2',4,4'-tetrabromodiphenyl ether (6-OH-BDE47), were detected in the phenolic fraction of extracts from most of the specimens; Sargassum oligosystum had the highest concentrations (101 ng/g fresh weight (fw)). The corresponding phenoxyanisole, 2'-methoxy-2,3',4,5'-tetrabromodiphenyl ether (2'-MeO-BDE68), was most abundant in Sargassum aff. bataanense (229 ng/g fw), followed by Padina sp., and 6-methoxy-2,2',4,4'-tetrabromodiphenyl ether (6-MeO-BDE47) was predominant in Jania adhaerens (29 ng/g fw). Hydroxy-pentaBDEs, hydroxy-methoxy-tetraBDEs, dihydroxy-tetraBDEs, dihydroxy-tetrabromobiphenyl, and hydroxy-tetrabromodibenzo-p-dioxins were also detected. The present study demonstrates that these aquatic plant species could be an abundant source of OH-PBDEs and MeO-PBDEs found in higher trophic organisms in the Asia-Pacific region.

  16. Levelized cost of energy and sensitivity analysis for the hydrogen-bromine flow battery

    NASA Astrophysics Data System (ADS)

    Singh, Nirala; McFarland, Eric W.

    2015-08-01

    The technoeconomics of the hydrogen-bromine flow battery are investigated. Using existing performance data the operating conditions were optimized to minimize the levelized cost of electricity using individual component costs for the flow battery stack and other system units. Several different configurations were evaluated including use of a bromine complexing agent to reduce membrane requirements. Sensitivity analysis of cost is used to identify the system elements most strongly influencing the economics. The stack lifetime and round-trip efficiency of the cell are identified as major factors on the levelized cost of electricity, along with capital components related to hydrogen storage, the bipolar plate, and the membrane. Assuming that an electrocatalyst and membrane with a lifetime of 2000 cycles can be identified, the lowest cost market entry system capital is 220 kWh-1 for a 4 h discharge system and for a charging energy cost of 0.04 kWh-1 the levelized cost of the electricity delivered is 0.40 kWh-1. With systems manufactured at large scales these costs are expected to be lower.

  17. Electrospun Nafion®/Polyphenylsulfone composite membranes for regenerative Hydrogen bromine fuel cells

    DOE PAGES

    Park, Jun; Wycisk, Ryszard; Pintauro, Peter N.; ...

    2016-02-29

    Here, the regenerative H2/Br2-HBr fuel cell, utilizing an oxidant solution of Br2 in aqueous HBr, shows a number of benefits for grid-scale electricity storage. The membrane-electrode assembly, a key component of a fuel cell, contains a proton-conducting membrane, typically based on the perfluorosulfonic acid (PFSA) ionomer. Unfortunately, the high cost of PFSA membranes and their relatively high bromine crossover are serious drawbacks. Nanofiber composite membranes can overcome these limitations. In this work, composite membranes were prepared from electrospun dual-fiber mats containing Nafion® PFSA ionomer for facile proton transport and an uncharged polymer, polyphenylsulfone (PPSU), for mechanical reinforcement, and swelling control.more » After electrospinning, Nafion/PPSU mats were converted into composite membranes by softening the PPSU fibers, through exposure to chloroform vapor, thus filling the voids between ionomer nanofibers. It was demonstrated that the relative membrane selectivity, referenced to Nafion® 115, increased with increasing PPSU content, e.g., a selectivity of 11 at 25 vol% of Nafion fibers. H2-Br2 fuel cell power output with a 65 m thick membrane containing 55 vol% Nafion fibers was somewhat better than that of a 150 m Nafion® 115 reference, but its cost advantage due to a four-fold decrease in PFSA content and a lower bromine species crossover make it an attractive candidate for use in H2/Br2-HBr systems.« less

  18. Production of hydrogen bromide by bromine-methane reactions at elevated temperature.

    SciTech Connect

    Bradshaw, Robert W.; Larson, Richard S.

    2003-05-01

    Hydrogen bromide is a potentially useful intermediate for hydrogen production by electrolysis because it has a low cell potential and is extremely soluble in water. Processes have been proposed to exploit these properties, but among the important issues to be resolved is the efficiency of HBr production from hydrocarbon precursors. This investigation evaluated a fundamental facet of such a technology by studying the reaction of methane and bromine at elevated temperature to determine the yield and kinetics of HBr formation. Laboratory experimentation and computational chemistry were combined to provide a description of this reaction for possible application to reactor design at a larger scale. Experimental studies with a tubular flow reactor were used to survey a range of reactant ratios and reactor residence times at temperatures between 500 C and 800 C. At temperatures near 800 C with excess methane, conversions of bromine to HBr exceeded 90% and reaction products included solid carbon (soot) in stoichiometric amounts. At lower temperatures, HBr conversion was significantly reduced, the products included much less soot, and the formation of bromocarbon compounds was indicated qualitatively. Calculations of chemical equilibrium behavior and reaction kinetics for the experimental conditions were performed using the Sandia CHEMKIN package. An elementary multistep mechanism for the gas-phase chemistry was used together with a surface mechanism that assumed facile deposition of radical species at the reactor walls. Simulations with the laminar-flow boundary-layer code of the CHEMKIN package gave reasonable agreement with experimental data.

  19. Formation of brominated dibenzofurans from pyrolysis of the polybrominated biphenyl fire retardant, firemaster FF-1.

    PubMed

    O'Keefe, P W

    1978-04-01

    The polybrominated biphenyl (PBB) fire retardant, FireMaster FF-1, was pyrolyzed for 20 min at 380-400 degrees C in open glass tubes and in tubes sealed after nitrogen flushing. The pyrolyzed residue was extracted with benzene, and extracts were cleaned up on columns of graphite (Carbopack A) and alumina. Analysis was carried out by low resolution direct probe mass spectrometry (MS). Spectra from extracts of the open tube pyrolyzed material had a series of ions characteristic of tetra- and pentabrominated dibenzofurans as evidenced by comparison with spectra from 2,3,7,8-tetrabromodibenzofuran (TBDF). Confirmatory evidence for the brominated dibenzofurans was obtained by high resolution MS dual ion analysis of certain fragment and molecular ions. Recovery values of TBDF through the cleanup procedure averaged 50% and, using this recovery value and TBDF as an external standard, dual ion analyses indicated that 40 ppm tetra- and 4 ppm pentabrominanted dibenzofuran were produced based on the PBB level used in the pyrolysis experiments. Additional analysis of the open tube pyrolyzed material by gas chromatography/mass spectrometry provided evidence that there was one tetrabromodibenzofuran compound with a retention time equal to that of TBDF. Trace levels (less than 1 ppm) of the molecular ion of tetrabrominated dibenzofuran were found after analysis by low resolution MS of the PBB pyrolyzed under nitrogen in sealed tubes. The experimental evidence is consistent with a mechanism for brominated dibenzofuran formation involving attack of oxygen on PBB compounds.

  20. Development of Zinc/Bromine Batteries for Load-Leveling Applications: Phase 2 Final Report

    SciTech Connect

    CLARK,NANCY H.; EIDLER,PHILLIP

    1999-10-01

    This report documents Phase 2 of a project to design, develop, and test a zinc/bromine battery technology for use in utility energy storage applications. The project was co-funded by the U.S. Department of Energy Office of Power Technologies through Sandia National Laboratories. The viability of the zinc/bromine technology was demonstrated in Phase 1. In Phase 2, the technology developed during Phase 1 was scaled up to a size appropriate for the application. Batteries were increased in size from 8-cell, 1170-cm{sup 2} cell stacks (Phase 1) to 8- and then 60-cell, 2500-cm{sup 2} cell stacks in this phase. The 2500-cm{sup 2} series battery stacks were developed as the building block for large utility battery systems. Core technology research on electrolyte and separator materials and on manufacturing techniques, which began in Phase 1, continued to be investigated during Phase 2. Finally, the end product of this project was a 100-kWh prototype battery system to be installed and tested at an electric utility.

  1. Nitrogenous disinfection byproducts in English drinking water supply systems: Occurrence, bromine substitution and correlation analysis.

    PubMed

    Bond, Tom; Templeton, Michael R; Mokhtar Kamal, Nurul Hana; Graham, Nigel; Kanda, Rakesh

    2015-11-15

    Despite the recent focus on nitrogenous disinfection byproducts in drinking water, there is limited occurrence data available for many species. This paper analyses the occurrence of seven haloacetonitriles, three haloacetamides, eight halonitromethanes and cyanogen chloride in 20 English drinking water supply systems. It is the first survey of its type to compare bromine substitution factors (BSFs) between the haloacetamides and haloacetonitriles. Concentrations of the dihalogenated haloacetonitriles and haloacetamides were well correlated. Although median concentrations of these two groups were lower in chloraminated than chlorinated surface waters, median BSFs for both in chloraminated samples were approximately double those in chlorinated samples, which is significant because of the higher reported toxicity of the brominated species. Furthermore, median BSFs were moderately higher for the dihalogenated haloacetamides than for the haloacetonitriles. This indicates that, while the dihalogenated haloacetamides were primarily generated from hydrolysis of the corresponding haloacetonitriles, secondary formation pathways also contributed. Median halonitromethane concentrations were remarkably unchanging for the different types of disinfectants and source waters: 0.1 μg · mgTOC(-1) in all cases. Cyanogen chloride only occurred in a limited number of samples, yet when present its concentrations were higher than the other N-DBPs. Concentrations of cyanogen chloride and the sum of the halonitromethanes were not correlated with any other DBPs.

  2. Trihalomethanes in chlorine and bromine disinfected swimming pools: air-water distributions and human exposure.

    PubMed

    Lourencetti, Carolina; Grimalt, Joan O; Marco, Esther; Fernandez, Pilar; Font-Ribera, Laia; Villanueva, Cristina M; Kogevinas, Manolis

    2012-09-15

    This first study of trihalomethanes (THMs) in swimming pools using bromine agents for water disinfection under real conditions shows that the mixtures of these compounds are largely dominated by bromoform in a similar process as chloroform becomes the dominant THM in pools disinfected with chlorine agents. Bromoform largely predominates in air and water of the pool installations whose concentration changes are linearly correlated. However, the air concentrations of bromoform account for about 6-11% of the expected concentrations according to theoretical partitioning defined by the Henry law. Bromoform in exhaled air of swimmers is correlated with the air concentrations of this disinfectant by-product in the pool building. Comparison of the THM exhaled air concentrations between swimmers and volunteers bathing in the water without swimming or standing in the building outside the water suggest that physical activity enhance exposure to these disinfectant by-products. They also indicate that in swimming pools, besides inhalation, dermal absorption is a relevant route for the incorporation of THMs, particularly those with lower degree of bromination.

  3. Cyclic Performance Analysis of Hydrogen/Bromine Flow Batteries for Grid-Scale Energy Storage

    SciTech Connect

    Cho, KT; Tucker, MC; Ding, M; Ridgway, P; Battaglia, VS; Srinivasan, V; Weber, AZ

    2014-06-03

    This paper explores the critical factors dominating the cycle performance of the hydrogen/bromine redox flow battery (RFB). Carbon electrode oxidation to CO2 was seen as the dominant side reaction, which can be prevented by operating the cell below 1.4 V. Crossover of bromide species from the positive to the negative electrode, especially during charge, dominates the coulombic efficiency, and can result in dissolution of the Pt catalyst if an adequate hydrogen supply is not maintained. This paper also describes the tradeoffs in voltaic, energy, and coulombic efficiencies during cycling, including the determination of the peak energy efficiency with respect to the HBr concentration and current density. Long-term cycling demonstrates negligible cell-component degradation over 600 cycles (approximate to 3 months), with capacity loss caused by the bromine from the system, which can be mitigated by proper system design. The data and methodologies provided in this paper can be used to understand better the operation of this and other RFBs.

  4. Inorganic bromine in organic molecular crystals: Database survey and four case studies

    NASA Astrophysics Data System (ADS)

    Nemec, Vinko; Lisac, Katarina; Stilinović, Vladimir; Cinčić, Dominik

    2017-01-01

    We present a Cambridge Structural Database and experimental study of multicomponent molecular crystals containing bromine. The CSD study covers supramolecular behaviour of bromide and tribromide anions as well as halogen bonded dibromine molecules in crystal structures of organic salts and cocrystals, and a study of the geometries and complexities in polybromide anion systems. In addition, we present four case studies of organic structures with bromide, tribromide and polybromide anions as well as the neutral dibromine molecule. These include the first observed crystal with diprotonated phenazine, a double salt of phenazinium bromide and tribromide, a cocrystal of 4-methoxypyridine with the neutral dibromine molecule as a halogen bond donor, as well as bis(4-methoxypyridine)bromonium polybromide. Structural features of the four case studies are in the most part consistent with the statistically prevalent behaviour indicated by the CSD study for given bromine species, although they do exhibit some unorthodox structural features and in that indicate possible supramolecular causes for aberrations from the statistically most abundant (and presumably most favourable) geometries.

  5. Laser isotope separation

    DOEpatents

    Robinson, C.P.; Reed, J.J.; Cotter, T.P.; Boyer, K.; Greiner, N.R.

    1975-11-26

    A process and apparatus for separating isotopes by selective excitation of isotopic species of a volatile compound by tuned laser light is described. A highly cooled gas of the volatile compound is produced in which the isotopic shift is sharpened and defined. Before substantial condensation occurs, the cooled gas is irradiated with laser light precisely tuned to a desired wavelength to selectively excite a particular isotopic species in the cooled gas. The laser light may impart sufficient energy to the excited species to cause it to undergo photolysis, photochemical reaction or even to photoionize. Alternatively, a two-photon irradiation may be applied to the cooled gas to induce photolysis, photochemical reaction or photoionization. The process is particularly applicable to the separation of isotopes of uranium.

  6. Laser isotope separation

    DOEpatents

    Robinson, C. Paul; Jensen, Reed J.; Cotter, Theodore P.; Boyer, Keith; Greiner, Norman R.

    1988-01-01

    A process and apparatus for separating isotopes by selective excitation of isotopic species of a volatile compound by tuned laser light. A highly cooled gas of the volatile compound is produced in which the isotopic shift is sharpened and defined. Before substantial condensation occurs, the cooled gas is irradiated with laser light precisely tuned to a desired wavelength to selectively excite a particular isotopic species in the cooled gas. The laser light may impart sufficient energy to the excited species to cause it to undergo photolysis, photochemical reaction or even to photoionize. Alternatively, a two-photon irradiation may be applied to the cooled gas to induce photolysis, photochemical reaction or photoionization. The process is particularly applicable to the separation of isotopes of uranium.

  7. Photochemical isotope separation

    DOEpatents

    Robinson, C. Paul; Jensen, Reed J.; Cotter, Theodore P.; Greiner, Norman R.; Boyer, Keith

    1987-01-01

    A process for separating isotopes by selective excitation of isotopic species of a volatile compound by tuned laser light. A highly cooled gas of the volatile compound is produced in which the isotopic shift is sharpened and defined. Before substantial condensation occurs, the cooled gas is irradiated with laser light precisely tuned to a desired wavelength to selectively excite a particular isotopic species in the cooled gas. The laser light may impart sufficient energy to the excited species to cause it to undergo photochemical reaction or even to photoionize. Alternatively, a two-photon irradiation may be applied to the cooled gas to induce photochemical reaction or photoionization. The process is particularly applicable to the separation of isotopes of uranium and plutonium.

  8. Determination of fluorine, chlorine and bromine in household products by means of oxygen bomb combustion and ion chromatography.

    PubMed

    Zhang, Shuai; Zhao, Tianbo; Wang, Jia; Qu, Xiaoling; Chen, Wei; Han, Yin

    2013-01-01

    A method for routine determination of fluorine, chlorine and bromine in household products was developed and validated. In this work, halogen analyses were made based on oxygen bomb combustion followed by ion chromatography (IC). The chromatographic analysis was performed by an IonPac AS19 hydroxide-selective anion-exchange column, a reagent free ion chromatograph eluent generator and an anion self-regenerating suppressor in 10 min. The response was linear (r ≥ 0.9995) in the entire investigated domain. The limit of detection for the halogens was in the range of 2 to 9 × 10(-3) mg/L and the limit of quantification was lower than 8 mg/Kg with 20 µL of injection volume. The certified reference material of ERM-EC 681k was pretreated using an oxygen bomb combustion procedure to demonstrate the precision of the proposed method. The quantitative analysis results obtained by IC for the target elements were 797 ± 9 mg/Kg chlorine and 786 ± 25 mg/Kg bromine, which were in good agreement with the certified values of 800 ± 4 mg/Kg chlorine, 770 ± 5 mg/Kg bromine for ERM-EC 681k, respectively. This validated method was successfully applied for the analysis of fluorine, chlorine and bromine in household product samples, and the variation of halogen contained among the tested samples was remarkable.

  9. Different speciation for bromine in brown and red algae, revealed by in vivo X-ray absorption spectroscopic studies.

    PubMed

    Küpper, Frithjof C; Leblanc, Catherine; Meyer-Klaucke, Wolfram; Potin, Philippe; Feiters, Martin C

    2014-08-01

    Members of various algal lineages are known to be strong producers of atmospherically relevant halogen emissions, that is a consequence of their capability to store and metabolize halogens. This study uses a noninvasive, synchrotron-based technique, X-ray absorption spectroscopy, for addressing in vivo bromine speciation in the brown algae Ectocarpus siliculosus, Ascophyllum nodosum, and Fucus serratus, the red algae Gracilaria dura, G. gracilis, Chondrus crispus, Osmundea pinnatifida, Asparagopsis armata, Polysiphonia elongata, and Corallina officinalis, the diatom Thalassiosira rotula, the dinoflagellate Lingulodinium polyedrum and a natural phytoplankton sample. The results highlight a diversity of fundamentally different bromine storage modes: while most of the stramenopile representatives and the dinoflagellate store mostly bromide, there is evidence for Br incorporated in nonaromatic hydrocarbons in Thalassiosira. Red algae operate various organic bromine stores - including a possible precursor (by the haloform reaction) for bromoform in Asparagopsis and aromatically bound Br in Polysiphonia and Corallina. Large fractions of the bromine in the red algae G. dura and C. crispus and the brown alga F. serratus are present as Br(-) defects in solid KCl, similar to what was reported earlier for Laminaria parts. These results are discussed according to different defensive strategies that are used within algal taxa to cope with biotic or abiotic stresses.

  10. Bromination of Aromatic Compounds by Residual Bromide in Sodium Chloride Matrix Modifier Salt During Heated Headspace GC/MS Analysis

    EPA Science Inventory

    Analytical artifacts attributed to the bromination of toluene, xylenes, and trimethylbenzenes were found during the heated headspace gas chromatography/mass spectrometry (GC/MS) analysis of aqueous samples. The aqueous samples were produced from Fenton-like chemical oxidation rea...

  11. Rapid Formation of Molecular Bromine from Deliquesced NaBr Aerosol in the Presence of Ozone and UV Light

    EPA Science Inventory

    The formation of gas-phase bromine from aqueous sodium bromide aerosols is investigated through a combination of chamber experiments and chemical kinetics modeling. Experiments show that Br2(g) is produced rapidly from deliquesced NaBr aerosols in the presence of OH radicals prod...

  12. Analysis of Bromination of Ethylbenzene Using a 45 MHz NMR Spectrometer: An Undergraduate Organic Chemistry Laboratory Experiment

    ERIC Educational Resources Information Center

    Isaac-Lam, Meden F.

    2014-01-01

    A 45 MHz benchtop NMR spectrometer is used to identify the structures and determine the amount of 1-bromoethylbenzene and 1,1-dibromoethylbenzene produced from free-radical bromination of ethylbenzene. The experiment is designed for nonchemistry majors, specifically B.S. Biology students, in a predominantly undergraduate institution with…

  13. M1 decay of the 2 sup 3 S sub 1 state of helium-like bromine

    SciTech Connect

    Dunford, R.W.; Liu, C.J.; Berry, H.G.; Raphaelian, M.L.A. ); Church, D.A. ); Hass, M. ); Curtis, L.J. )

    1991-08-05

    We have measured the lifetime of the 2 {sup 3}S{sub 1} level in helium-like bromine with the result {tau}{sup exp} 2 {sup 3}S{sub 1}=224.1 (7.1) ps, in agreement with theory. Our error is dominated by uncertainties in the correction for the effects of cascades from highly excited states.

  14. DETERMINATION OF BROMATE IN THE PRESENCE OF BROMINATED HALOACETIC ACIDS BY ION CHROMATOGRAPHY WITH INDUCTIVELY COUPLED PLASMA MASS SPECTROMETRIC DETECTION

    EPA Science Inventory

    Bromate is a disinfection by product (DBP) in drinking water that is formed during the ozonation of a source water containing bromide. Brominated haloacetic acids are DBPs that are anions at near -neutral phs. The anion character of bromoacetic acid (pKa=2.7) is similar to bromat...

  15. COMPUTATIONAL INVESTIGATION OF CHEMICAL REACTIVITY IN RELATION TO BIOACTIVATION AND TOXICITY ACROSS CLASSES OF HALOORGANICS: BROMINATION VS. CHLORINATION

    EPA Science Inventory

    COMPUTATIONAL INVESTIGATION OF CHEMICAL REACTIVITY IN RELATION TO BIOACTIV A TION AND TOXICITY ACROSS CLASSES OF HALOORGANICS: BROMINATION VS. CHLORINATION.

    Halogenation is a common feature of many classes of environmental contaminants, and often plays a crucial role in po...

  16. Bromine Incorporation in Regulated and Emerging DBPs and the Relative Predominance of Mono-, Di-, and Trihalogenated DBPs

    EPA Science Inventory

    Brominated disinfection by-products (DBPs) (in general) appear to be more cytotoxic and genotoxic than the chlorinated species, and some of the dihalogenated species are more toxic than the trihalogenated analogues; however, many of the more toxic species are not routinely measur...

  17. PILOT-SCALE STUDIES ON THE EFFECT OF BROMINE ADDITION ON THE EMISSIONS OF CHLORINATED ORGANIC COMBUSTION BY-PRODUCTS

    EPA Science Inventory

    The addition of brominated organic compounds to the feed of a pilot-scale incinerator burning chlorinated waste has been found previously, under some circumstances, to enhance emissions of volatile and semivolatile organic chlorinated products of incomplete combustion (PiCs) incl...

  18. Suppressing effect of calcium-based waste on control of bromine flux during the pyrolysis of printed circuit boards.

    PubMed

    Jie, Guan; Min, Xu; Wu, Wenjie; Zhang, Chenglong; Wang, Jingwei; Bai, Jianfeng

    2012-11-01

    The effect of calcium-based addition on the brominate flux during printed circuit board (PCB) pyrolysis was investigated. It was found that bromine (Br) can be effectively fixed in solid phase during PCB pyrolysis by adding calcium-based waste materials. Phenol and 4-ethylphenol are the major products of pyrolysis. When the two kinds of red mud were used as additive, their content was 85.25 and 84.81%, respectively, which was higher than others. The 2-bromophenol and 2-bromo-4-methyl-benzene are the main Br-containing pyrolysis volatiles. After adding calcium-based additive, these two volatiles were apparently reduced and only small amounts of 2-bromo-4-methyl-benzene were detected in the products, namely 0.71 and 0.86%, respectively for the two kinds of red mud. Hence, no matter from the perspective of product use or simple Br-fixing, the bromine in the three-phase products can be effectively regulated and controlled by adding calcium-based waste residue during PCB pyrolysis. Finally, the Br-fixing mechanism was analysed. As a result, when calcium-based waste materials were added to the PCB pyrolysis it made bromine fix easily in the resident yielding a byproduct that can be further used.

  19. Production of bromoform and dibromomethane by Giant Kelp: Factors affecting release and comparison to anthropogenic bromine sources

    USGS Publications Warehouse

    Goodwin, K.D.; North, W.J.; Lidstrom, M.E.

    1998-01-01

    Macrocystis pyrifera (Giant Kelp), a dominant macroalgal species in southern California, produced 171 ng per g fresh wt (gfwt) per day of CHBr3 and 48 ng gfwt-1 d-1 of CH2Br2 during laboratory incubations of whole blades. Comparable rates were measured during in situ incubations of intact fronds. Release of CHBr3 and CH2Br2 by M. pyrifera was affected by light and algal photosynthetic activity, suggesting that environmental factors influencing kelp physiology can affect halomethane release to the atmosphere. Data from H2O2 additions suggest that brominated methane production during darkness is limited by bromide oxidant supply. A bromine budget constructed for a region of southern California indicated that bromine emitted from the use of CH3Br as a fumigant (1 x 108 g Br yr-1) dominates macroalgal sources (3 x 106 g Br yr-1). Global projections, however, suggest that combined emissions of marine algae (including microalgae) contribute substantial amounts of bromine to the global cycle, perhaps on the same order of magnitude as anthropogenic sources.

  20. Neutron and Charged-Particle Induced Cross Sections for Radiochemistry in the Region of Bromine and Krypton

    SciTech Connect

    Hoffman, R; Dietrich, F; Bauer, R; Kelley, K; Mustafa, M

    2004-07-23

    We have developed a set of modeled nuclear reaction cross sections for use in radiochemical diagnostics. Systematics for the input parameters required by the Hauser-Feshbach statistical model were developed and used to calculate neutron and proton induced nuclear reaction cross sections in the mass region of bromine and krypton (34 {le} Z {le} 37, 40 {le} N {le} 47).

  1. Influence of bromine substitution pattern on the singlet oxygen generation efficiency of two-photon absorbing chromophores.

    PubMed

    Lanoë, Pierre-Henri; Gallavardin, Thibault; Dupin, Aurore; Maury, Olivier; Baldeck, Patrice L; Lindgren, Mikael; Monnereau, Cyrille; Andraud, Chantal

    2012-08-21

    A molecular engineering strategy based on rational variations of the bromine substitution pattern in two-photon absorbing singlet oxygen sensitizers allows studying the relations that exist between the positioning of an inter-system crossing promoter on the charge-transfer chromophore and its ability to generate singlet oxygen.

  2. Electrophilic Anti Addition of Bromine to 2-Methylbut-2-Ene with the N-Methylpyrrolidin-2-One Hydrotribromide Complex

    ERIC Educational Resources Information Center

    Berrien, Jean-Francois; Provot, Olivier; Joseph, Delphine; Bekaert, Alain

    2004-01-01

    The N-methylpyrrolidin-2-one hydrotribromide complex (MPHT) is a stable solid that can be stored several months at room temperature. The MPHT is not corrosive, not necrosing, less toxic and easier to handle for students as compared to the molecular bromine.

  3. Bromination from the Macroscopic Level to the Tracer Radiochemical Level: 76Br Radiolabeling of Aromatic Compounds via Electrophilic Substitution

    PubMed Central

    Zhou, Dong; Zhou, Haibing; Jenks, Carl C.; Lewis, Jason S.; Katzenellenbogen, John A.; Welch, Michael J.

    2009-01-01

    No-carrier-added (NCA) 76Br labeling of 4-(5-Acetoxy-7-bromobenzoxazol-2-yl)phenyl acetate, a diacetate-protected estrogen-receptor beta (ERβ) selective ligand, was carried out successfully using [76Br]bromide ion. The labeling was achieved via oxidative electrophilic destannylation of an organotin precursor molecule by modification of the leaving group (from Bu3Sn to Me3Sn) and the addition of methanol to the reaction mixture. The differences between the oxidative bromination reaction under small-scale macroscopic vs tracer level radiochemical conditions were explored in terms of effective brominating agents, which depend greatly on the nature of the solvent during the radiochemical bromination, and the potential interference by trace levels of highly reactive impurities in the reaction that compete for the desired bromination at the NCA level. Our observations, and our development of experimental protocols for successful radiobromination at the tracer NCA-scale, should be applicable to the synthesis of other radiobromine-labeled organic compounds of potential interest as PET radiopharmaceuticals and radiotherapy agents. PMID:19260733

  4. Meteoritic Sulfur Isotopic Analysis

    NASA Technical Reports Server (NTRS)

    Thiemens, Mark H.

    1996-01-01

    Funds were requested to continue our program in meteoritic sulfur isotopic analysis. We have recently detected a potential nucleosynthetic sulfur isotopic anomaly. We will search for potential carriers. The documentation of bulk systematics and the possible relation to nebular chemistry and oxygen isotopes will be explored. Analytical techniques for delta(sup 33), delta(sup 34)S, delta(sup 36)S isotopic analysis were improved. Analysis of sub milligram samples is now possible. A possible relation between sulfur isotopes and oxygen was detected, with similar group systematics noted, particularly in the case of aubrites, ureilites and entstatite chondrites. A possible nucleosynthetic excess S-33 has been noted in bulk ureilites and an oldhamite separate from Norton County. High energy proton (approximately 1 GeV) bombardments of iron foils were done to experimentally determine S-33, S-36 spallogenic yields for quantitation of isotopic measurements in iron meteorites. Techniques for measurement of mineral separates were perfected and an analysis program initiated. The systematic behavior of bulk sulfur isotopes will continue to be explored.

  5. Reaction of bromine and chlorine with phenolic compounds and natural organic matter extracts--Electrophilic aromatic substitution and oxidation.

    PubMed

    Criquet, Justine; Rodriguez, Eva M; Allard, Sebastien; Wellauer, Sven; Salhi, Elisabeth; Joll, Cynthia A; von Gunten, Urs

    2015-11-15

    Phenolic compounds are known structural moieties of natural organic matter (NOM), and their reactivity is a key parameter for understanding the reactivity of NOM and the disinfection by-product formation during oxidative water treatment. In this study, species-specific and/or apparent second order rate constants and mechanisms for the reactions of bromine and chlorine have been determined for various phenolic compounds (phenol, resorcinol, catechol, hydroquinone, phloroglucinol, bisphenol A, p-hydroxybenzoic acid, gallic acid, hesperetin and tannic acid) and flavone. The reactivity of bromine with phenolic compounds is very high, with apparent second order rate constants at pH 7 in the range of 10(4) to 10(7) M(-1) s(-1). The highest value was recorded for the reaction between HOBr and the fully deprotonated resorcinol (k = 2.1 × 10(9) M(-1) s(-1)). The reactivity of phenolic compounds is enhanced by the activating character of the phenolic substituents, e.g. further hydroxyl groups. With the data set from this study, the ratio between the species-specific rate constants for the reactions of chlorine versus bromine with phenolic compounds was confirmed to be about 3000. Phenolic compounds react with bromine or chlorine either by oxidation (electron transfer, ET) or electrophilic aromatic substitution (EAS) processes. The dominant process mainly depends on the relative position of the hydroxyl substituents and the possibility of quinone formation. While phenol, p-hydroxybenzoic acid and bisphenol A undergo EAS, hydroquinone, catechol, gallic acid and tannic acid, with hydroxyl substituents in ortho or para positions, react with bromine by ET leading to quantitative formation of the corresponding quinones. Some compounds (e.g. phloroglucinol) show both partial oxidation and partial electrophilic aromatic substitution and the ratio observed for the pathways depends on the pH. For the reaction of six NOM extracts with bromine, electrophilic aromatic substitution

  6. Isotopically controlled semiconductors

    SciTech Connect

    Haller, Eugene E.

    2006-06-19

    The following article is an edited transcript based on the Turnbull Lecture given by Eugene E. Haller at the 2005 Materials Research Society Fall Meeting in Boston on November 29, 2005. The David Turnbull Lectureship is awarded to recognize the career of a scientist who has made outstanding contributions to understanding materials phenomena and properties through research, writing, and lecturing, as exemplified by the life work of David Turnbull. Haller was named the 2005 David Turnbull Lecturer for his 'pioneering achievements and leadership in establishing the field of isotopically engineered semiconductors; for outstanding contributions to materials growth, doping and diffusion; and for excellence in lecturing, writing, and fostering international collaborations'. The scientific interest, increased availability, and technological promise of highly enriched isotopes have led to a sharp rise in the number of experimental and theoretical studies with isotopically controlled semiconductor crystals. This article reviews results obtained with isotopically controlled semiconductor bulk and thin-film heterostructures. Isotopic composition affects several properties such as phonon energies, band structure, and lattice constant in subtle, but, for their physical understanding, significant ways. Large isotope-related effects are observed for thermal conductivity in local vibrational modes of impurities and after neutron transmutation doping. Spectacularly sharp photoluminescence lines have been observed in ultrapure, isotopically enriched silicon crystals. Isotope multilayer structures are especially well suited for simultaneous self- and dopant-diffusion studies. The absence of any chemical, mechanical, or electrical driving forces makes possible the study of an ideal random-walk problem. Isotopically controlled semiconductors may find applications in quantum computing, nanoscience, and spintronics.

  7. Assessing the persistence, bioaccumulation potential and toxicity of brominated flame retardants: data availability and quality for 36 alternative brominated flame retardants.

    PubMed

    Stieger, Greta; Scheringer, Martin; Ng, Carla A; Hungerbühler, Konrad

    2014-12-01

    Polybrominated diphenylethers (PBDEs) and hexabromocyclododecane (HBCDD) are major brominated flame retardants (BFRs) that are now banned or under restrictions in many countries because of their persistence, bioaccumulation potential and toxicity (PBT properties). However, there is a wide range of alternative BFRs, such as decabromodiphenyl ethane and tribromophenol, that are increasingly used as replacements, but which may possess similar hazardous properties. This necessitates hazard and risk assessments of these compounds. For a set of 36 alternative BFRs, we searched 25 databases for chemical property data that are needed as input for a PBT assessment. These properties are degradation half-life, bioconcentration factor (BCF), octanol-water partition coefficient (Kow), and toxic effect concentrations in aquatic organisms. For 17 of the 36 substances, no data at all were found for these properties. Too few persistence data were available to even assess the quality of these data in a systematic way. The available data for Kow and toxicity show surprisingly high variability, which makes it difficult to identify the most reliable values. We propose methods for systematic evaluations of PBT-related chemical property data that should be performed before data are included in publicly available databases. Using these methods, we evaluated the data for Kow and toxicity in more detail and identified several inaccurate values. For most of the 36 alternative BFRs, the amount and the quality of the PBT-related property data need to be improved before reliable hazard and risk assessments of these substances can be performed.

  8. ISOTOPE SEPARATING APPARATUS

    DOEpatents

    Kudravetz, M.K.; Greene, H.B.

    1958-09-16

    This patent relates to control systems for a calutron and, in particular, describes an electro-mechanical system for interrupting the collection of charged particles when the ratio between the two isotopes being receivcd deviates from a predetermined value. One embodiment of the invention includes means responsive to the ratio between two isotopes being received for opening a normally closed shutter over the receiver entrance when the isotope ratio is the desired value. In another form of the invention the collection operation is interrupted by changing the beam accelerating voltage to deflect the ion beam away from the receiver.

  9. Molecular simulations and density functional theory calculations of bromine in clathrate hydrate phases

    SciTech Connect

    Dureckova, Hana Woo, Tom K.; Alavi, Saman

    2016-01-28

    Bromine forms a tetragonal clathrate hydrate structure (TS-I) very rarely observed in clathrate hydrates of other guest substances. The detailed structure, energetics, and dynamics of Br{sub 2} and Cl{sub 2} in TS-I and cubic structure I (CS-I) clathrate hydrates are studied in this work using molecular dynamics and quantum chemical calculations. X-ray diffraction studies show that the halogen-water–oxygen distances in the cages of these structures are shorter than the sum of the van der Waals radii of halogen and oxygen atoms. This suggests that the stabilizing effects of halogen bonding or other non-covalent interactions (NCIs) may contribute to the formation of the unique tetragonal bromine hydrate structure. We performed molecular dynamics simulations of Br{sub 2} and Cl{sub 2} clathrate hydrates using our previously developed five-site charge models for the dihalogen molecules [Dureckova et al. Can. J. Chem. 93, 864 (2015)] which reproduce the computed electrostatic potentials of the dihalogens and account for the electropositive σ-hole of the halogen bond donor (the dihalogen). Analysis of the radial distribution functions, enthalpies of encapsulation, velocity and orientation autocorrelation functions, and polar angle distributions are carried out for Br{sub 2} and Cl{sub 2} guests in various cages to contrast the properties of these guests in the TS-I and CS-I phases. Quantum chemical partial geometry optimizations of Br{sub 2} and Cl{sub 2} guests in the hydrate cages using the M06-2X functional give short halogen-water distances compatible with values observed in X-ray diffraction experiments. NCI plots of guest-cage structures are generated to qualitatively show the relative strength of the non-bonding interactions between dihalogens and water molecules. The differences between behaviors of Br{sub 2} and Cl{sub 2} guests in the hydrate cages may explain why bromine forms the unique TS-I phase.

  10. Photochemical degradation of a brominated flame retardant (tetrabromobisphenol A) in ice under field and laboratory conditions

    NASA Astrophysics Data System (ADS)

    Waligroski, G.; Grannas, A. M.

    2013-12-01

    Studies of brominated flame retardants have raised awareness of their potential environmental impact as toxic compounds. Because these compounds are now globally distributed, including in the Polar Regions, it is important to assess their potential fate in the environment. It has been shown that active photochemistry occurs in sunlit snow and ice, but there is little information regarding potential photochemical degradation of brominated flame retardants in snow and ice. The purpose of this research is to investigate the direct and indirect photochemical transformation pathways of a widely used brominated flame retardant, tetrabromobisphenol A (TBBPA). We have conducted field-based experiments in Barrow, Alaska to investigate the potential photochemical degradation of TBBPA in snow and ice under environmentally-relevant conditions. Field-based results show that TBBPA is efficiently degraded under direct photolysis conditions in frozen aqueous samples under natural Barrow sunlight. In aqueous solution the light absorption properties of TBBPA are pH dependent. Therefore, the photodegradation of TBBPA in snow and ice will be highly pH dependent. Reactions that are pH dependent may be affected by the nature of the liquid-like layers in snow/ice as well as the presence of other solutes that may indirectly affect the local pH experienced by TBBPA in snow and ice samples. In order to establish how the effective pH of liquid-like regions in ice might impact the degradation of TBBPA, various salts (sodium chloride, sodium fluoride, sodium bromide, ammonium chloride, ammonium acetate and ammonium sulfate) were added to aqueous solutions of TBBPA. Upon freezing, these different salts will induce pH differences in the liquid-like regions of the sample due to a phenomenon known as the freezing potential. Observed reactivity differences upon addition of these salts will be evaluated and discussed. Additionally, the presence of natural dissolved organic matter (DOM), an effective

  11. Effect of brominated furanones on the formation of biofilm by Escherichia coli on polyvinyl chloride materials.

    PubMed

    Lianhua, Ye; Yunchao, Huang; Geng, Xu; Youquang, Zhou; Guangqiang, Zhao; Yujie, Lei

    2013-01-01

    To study the influence of brominated furanones on the biofilm (BF) formation by Escherichia coli (E. coli) on polyvinyl chloride (PVC) material, and to provide new ways of surface modification of materials to clinically prevent biomaterial centered infection. Three brominated furanones, dissolved in ethanol, furanone-1(3,4-dibromo-5-hydroxyl-furanone), furanone-2(4-bromo-5-(4-methoxypheny)-3-(methylamino)-furanone), and furanone-3(3,4-dibromo-5,5-dimethoxypheny-2(5H)-furanone) with representative chemical structure, were coated on the surfaces of separate PVC materials (1 × 1 cm), respectively. The surface-modified PVC materials were incubated with E. coli and for controls, 75 % ethanol-treated PVC materials were used. This treatment played as control group. The cultivation incubations were for 6, 12, 18, and 24 h. The thickness of bacterial BF and bacterial community quantity unit area on the PVC materials was determined by confocal laser scanning microscopy (CLSM), and the surface structure of bacterial BF formation was examined by scanning electron microscopy (SEM). The results of CLSM indicated the thickness of bacterial BF and bacterial community quantity unit area on PVC materials treated with furanone-3 were significantly lower than that of control at all time points (P < 0.05), whereas, the differences between furanone-1 and furanone-2 groups and control group were not significantly different (P > 0.05). The results of SEM indicated that after 6 h incubation, the quantity of bacterial attachment to the surface of PVC material treated with furanone-3 was lower than the control group. By 18 h incubation there was completely formed BF structure on the surface of control PVC material. However, there was no significant BF formation on the surface of PVC material treated with furanone-3. The impact of different brominated furanones on SA biofilm formation on the surface of PVC materials are different, furanone-3 can inhibit E. coli biofilm formation on the

  12. Investigating the lifetime of bromine-quenched G.M. Counters with temperature

    NASA Astrophysics Data System (ADS)

    Abilama, Marc; Bates, Mike; Lohstroh, Annika

    2015-09-01

    The amount of halogen quench gas as a percentage of the total fill gas contained within a gas-filled Geiger-Müller detector is directly linked to its operational characteristics. Preserving this halogen gas will help maintain the operating lifetime of the detectors. Such halogen gases are highly corrosive and the small quantities within a gas-filled detector can deplete rapidly via interactions with surrounding materials. The rate of interactions is thought to be proportional to not only temperature, but also to the current initiated by ionisation events associated with the formation of each signal pulse. As all pulses are of similar magnitudes, GM detector operational lifetimes are quantified in accumulated counts rather than a given operating time. We have studied three different types of corrosion-resistant mechanisms to protect the bromine halogen gas from any interactions with 446 stainless steel detector components of ZP1200 Geiger-Müller tubes at temperatures up to 125 °C. Three types of surface treatments for these detectors used were labelled as "raw" using only an oxygen-plasma-bombardment process, "passivated" using a combination of nitric acid passivation followed by an oxygen plasma-bombardment process, and thirdly plating with a few micron thickness of chromium followed by an oxygen plasma-bombardment process. 32 detector samples were irradiated at room temperature with a Caesium-137 source at dose rates of approximately 1.3 mSv/hr up to 5.7×1010 accumulated counts; another 32 detector samples were aged to 3.3×1010 counts at 125 °C. At room temperature, the chromium-plated samples exhibited an initial rise in their starting voltage readings. All other detector performance characteristics, for all detector types, did not change significantly during the ageing process, and the surface morphology of the detector cathodes was unaffected. At 125 °C, the chromium-based plating produced the most stable long-term response. These chromium-plated samples

  13. Air-snowpack exchange of bromine, ozone and mercury in the springtime Arctic simulated by the 1-D model PHANTAS - Part 1: In-snow bromine activation and its impact on ozone

    NASA Astrophysics Data System (ADS)

    Toyota, K.; McConnell, J. C.; Staebler, R. M.; Dastoor, A. P.

    2013-08-01

    To provide a theoretical framework towards better understanding of ozone depletion events (ODEs) and atmospheric mercury depletion events (AMDEs) in the polar boundary layer, we have developed a one-dimensional model that simulates multiphase chemistry and transport of trace constituents from porous snowpack and through the atmospheric boundary layer (ABL) as a unified system. In this paper, we describe a general configuration of the model and the results of simulations related to reactive bromine release from the snowpack and ODEs during the Arctic spring. The model employs a chemical mechanism adapted from the one previously used for the simulation of multiphase halogen chemistry involving deliquesced sea-salt aerosols in the marine boundary layer. A common set of aqueous-phase reactions describe chemistry both in the liquid-like (or brine) layer on the grain surface of the snowpack and in "haze" aerosols mainly composed of sulfate in the atmosphere. The process of highly soluble/reactive trace gases, whether entering the snowpack from the atmosphere or formed via gas-phase chemistry in the snowpack interstitial air (SIA), is simulated by the uptake on brine-covered snow grains and subsequent reactions in the aqueous phase while being traveled vertically within the SIA. A "bromine explosion", by which, in a conventional definition, HOBr formed in the ambient air is deposited and then converted heterogeneously to Br2, is a dominant process of reactive bromine formation in the top 1 mm (or less) layer of the snowpack. Deeper in the snowpack, HOBr formed within the SIA leads to an in-snow bromine explosion, but a significant fraction of Br2 is also produced via aqueous radical chemistry in the brine on the surface of the snow grains. These top- and deeper-layer productions of Br2 both contribute to the Br2 release into the atmosphere, but the deeper-layer production is found to be more important for the net outflux of reactive bromine. Although ozone is removed via

  14. Lithium isotope geochemistry and origin of Canadian shield brines.

    PubMed

    Bottomley, D J; Chan, L H; Katz, A; Starinsky, A; Clark, I D

    2003-01-01

    Hypersaline calcium/chloride shield brines are ubiquitous in Canada and areas of northern Europe. The major questions relating to these fluids are the origin of the solutes and the concentration mechanism that led to their extreme salinity. Many chemical and isotopic tracers are used to solve these questions. For example, lithium isotope systematics have been used recently to support a marine origin for the Yellowknife shield brine (Northwest Territories). While having important chemical similarities to the Yellowknife brine, shield brines from the Sudbury/Elliot Lake (Ontario) and Thompson/Snow Lake (Manitoba) regions, which are the focus of this study, exhibit contrasting lithium behavior. Brine from the Sudbury Victor mine has lithium concentrations that closely follow the sea water lithium-bromine concentration trajectory, as well as delta6Li values of approximately -28/1000. This indicates that the lithium in this brine is predominantly marine in origin with a relatively minor component of crustal lithium leached from the host rocks. In contrast, the Thompson/Snow Lake brine has anomalously low lithium concentrations, indicating that it has largely been removed from solution by alteration minerals. Furthermore, brine and nonbrine mine waters at the Thompson mine have large delta6Li variations of approximately 30/1000, which primarily reflects mixing between deep brine with delta6Li of -35 +/- 2/1000 and near surface mine water that has derived higher delta6Li values through interactions with their host rocks. The contrary behavior of lithium in these two brines shows that, in systems where it has behaved conservatively, lithium isotopes can distinguish brines derived from marine sources.

  15. Perchlorate isotope forensics

    USGS Publications Warehouse

    Böhlke, J.K.; Sturchio, N.C.; Gu, B.; Horita, J.; Brown, G.M.; Jackson, W.A.; Batista, J.; Hatzinger, P.B.

    2005-01-01

    Perchlorate has been detected recently in a variety of soils, waters, plants, and food products at levels that may be detrimental to human health. These discoveries have generated considerable interest in perchlorate source identification. In this study, comprehensive stable isotope analyses ( 37Cl/35Cl and 18O/17O/ 16O) of perchlorate from known synthetic and natural sources reveal systematic differences in isotopic characteristics that are related to the formation mechanisms. In addition, isotopic analyses of perchlorate extracted from groundwater and surface water demonstrate the feasibility of identifying perchlorate sources in contaminated environments on the basis of this technique. Both natural and synthetic sources of perchlorate have been identified in water samples from some perchlorate occurrences in the United States by the isotopic method. ?? 2005 American Chemical Society.

  16. Isotopically controlled semiconductors

    SciTech Connect

    Haller, E.E.

    2004-11-15

    A review of recent research involving isotopically controlled semiconductors is presented. Studies with isotopically enriched semiconductor structures experienced a dramatic expansion at the end of the Cold War when significant quantities of enriched isotopes of elements forming semiconductors became available for worldwide collaborations. Isotopes of an element differ in nuclear mass, may have different nuclear spins and undergo different nuclear reactions. Among the latter, the capture of thermal neutrons which can lead to neutron transmutation doping, can be considered the most important one for semiconductors. Experimental and theoretical research exploiting the differences in all the properties has been conducted and will be illustrated with selected examples. Manuel Cardona, the longtime editor-in-chief of Solid State Communications has been and continues to be one of the major contributors to this field of solid state physics and it is a great pleasure to dedicate this review to him.

  17. Stable isotopes in mineralogy

    USGS Publications Warehouse

    O'Neil, J.R.

    1977-01-01

    Stable isotope fractionations between minerals are functions of the fundamental vibrational frequencies of the minerals and therefore bear on several topics of mineralogical interest. Isotopic compositions of the elements H, C, O, Si, and S can now be determined routinely in almost any mineral. A summary has been made of both published and new results of laboratory investigations, analyses of natural materials, and theoretical considerations which bear on the importance of temperature, pressure, chemical composition and crystal structure to the isotopic properties of minerals. It is shown that stable isotope studies can sometimes provide evidence for elucidating details of crystal structure and can be a powerful tool for use in tracing the reaction paths of mineralogical reactions. ?? 1977 Springer-Verlag.

  18. Recovery of bromine from waste gas-phase hydrogen bromide streams using an electrolytic membrane

    SciTech Connect

    Wauters, C.N; Winnick, J.

    1996-09-01

    An electrochemical cell is used to demonstrate a significant improvement in the recovery of bromine (Br{sub 2}) from waste gas-phase hydrogen bromide (HBr) streams. The continuous process operates at 300 C and utilizes reticulated vitreous carbon gas-diffusion electrodes, a molten (Li{sub 0.575}K{sub 0.133}Cs{sub 0.292})Br electrolyte, and borosilicate glass fiber membrane. HBr is simultaneously electrolytically decomposed and separated into a hydrogen enriched waste stream and pure anhydrous Br{sub 2} product stream. Simulated industrial waste streams containing HBr, nitrogen, water vapor, and organic compounds have been tested. These results include removals of greater than 90% and current densities approaching 1.0 A/cm{sup 2}.

  19. Impairment in the mesohippocampal dopamine circuit following exposure to the brominated flame retardant, HBCDD.

    PubMed

    Pham-Lake, Camille; Aronoff, Elizabeth B; Camp, Chad R; Vester, Aimee; Peters, Sam J; Caudle, W Michael

    2017-03-01

    Many chemicals have been used to increase the safety of consumer products by reducing their flammability and risk for ignition. Recent focus on brominated flame retardants, such as polybrominated diphenyl ethers (PBDEs) has shown them to contribute to neurobehavioral deficits in children, including learning and memory. As the manufacture and use of PBDEs have been reduced, replacement chemicals, such as hexabromocyclododecane (HBCDD) have been substituted. Our current study evaluated the neurotoxicity of HBCDD, concentrating on dopaminergic innervation to the hippocampus. Using an in vivo model, we exposed male mice to HBCDD and then assessed alterations to the dopamine synapse 6 weeks later. These exposures elicited significant reductions in presynaptic dopaminergic proteins, including TH, COMT, MAO-B, DAT, VMAT2, and alpha-synuclein. In contrast, postsynaptic dopamine receptors were not impaired. These findings suggest that the mesohippocampal dopamine circuit is vulnerable to HBCDD and the dopamine terminal may be a selective target for alteration.

  20. Effect of lightning strike on bromine intercalated graphite fiber/epoxy composites

    NASA Technical Reports Server (NTRS)

    Gaier, James R.; Slabe, Melissa E.; Brink, Norman O.

    1991-01-01

    Laminar composites were fabricated from pristine and bromine intercalated pitch based graphite fibers. It was found that laminar composites could be fabricated using either pristine or intercalated graphite fibers using standard fabrication techniques. The intercalated graphite fiber composites had electrical properties which were markedly improved over both the corresponding pitch based and polyacrylonitrile (PAN) based composites. Despite composites resistivities more than an order of magnitude lower for pitch based fiber composites, the lightning strike resistance was poorer than that of the Pan based fiber composites. This leads to the conclusion that the mechanical properties of the pitch fibers are more important than electrical or thermal properties in determining the lightning strike resistance. Based on indicated lightning strike tolerance for high elongation to failure materials, the use of vapor grown, rather than pitch based graphite fibers appears promising.

  1. Bromination and accompanying rearrangement of the polycyclic oxetane 2,4-oxytwistane.

    PubMed

    Rosenberg, Murray G; Billing, Peter; Brecker, Lothar; Brinker, Udo H

    2014-09-19

    Bromination of the polycyclic oxetane 2,4-oxytwistane (rac-(1R,3S,4R,7S,9R,11S)-2-oxatetracyclo[5.3.1.0(3,11).0(4,9)]undecane) was undertaken in order to form 2,4-dibromotwistane. The oxetane was subjected to the mild reagent combination CBr4/Ph3P in a fashion similar to that for the Appel and Corey-Fuchs reactions. NMR spectroscopy revealed that the isomeric dibromo compound 2,8-dibromoisotwistane (2,8-dibromotricyclo[4.3.1.0(3,7)]decane) was inadvertently formed. The conversion was prevented by migration of a C-C bond within the geometrically stressed C10 framework. Computational chemistry was used to model the structure of the polycyclic oxetane and to assess the component of total ring strain energy due to the four-membered heterocycle. Mechanistic aspects behind the skeletal rearrangement are also discussed.

  2. Flame retardant brominated styrene-based polymers. VI. Synthesis and characterization of dibromostyrene graft latices

    SciTech Connect

    Favstritsky, N.A.; Wang, J.L.

    1995-12-01

    Nine dibromostyrene-grafted commercial lattices were prepared in 8 oz bottles by an emulsion polymerization technique. Proper selection of lattices used in conjunction with the dibromostyrene monomer enables production of flame retardant latex products useful in a wide range of coating applications. The prime factor to be considered in the choice of a latex or a latex mixture to be grafted is the glass transition temperature(s) of the polymer(s) in the final latex desired. Lattices chosen for grafting are commercial lattices, such as Rhoplex HA-24 and HA-8, Hystretch V-29, Airflex 465, 4500, 4514 and 4530, Pliolite SBR latex and polybutadiene latex. The graft latex was characterized in terms of glass transition temperature, solids content, bromine content, grafted dibromostyrene and flame retardancy.

  3. Bromination of deoxycytidine by eosinophil peroxidase: A mechanism for mutagenesis by oxidative damage of nucleotide precursors

    PubMed Central

    Henderson, Jeffrey P.; Byun, Jaeman; Williams, Michelle V.; McCormick, Michael L.; Parks, William C.; Ridnour, Lisa A.; Heinecke, Jay W.

    2001-01-01

    Oxidants generated by eosinophils during chronic inflammation may lead to mutagenesis in adjacent epithelial cells. Eosinophil peroxidase, a heme enzyme released by eosinophils, generates hypobromous acid that damages tissue in inflammatory conditions. We show that human eosinophils use eosinophil peroxidase to produce 5-bromodeoxycytidine. Flow cytometric, immunohistochemical, and mass spectrometric analyses all demonstrated that 5-bromodeoxycytidine generated by eosinophil peroxidase was taken up by cultured cells and incorporated into genomic DNA as 5-bromodeoxyuridine. Although previous studies have focused on oxidation of chromosomal DNA, our observations suggest another mechanism for oxidative damage of DNA. In this scenario, peroxidase-catalyzed halogenation of nucleotide precursors yields products that subsequently can be incorporated into DNA. Because the thymine analog 5-BrUra mispairs with guanine in DNA, generation of brominated pyrimidines by eosinophils might constitute a mechanism for cytotoxicity and mutagenesis at sites of inflammation. PMID:11172002

  4. Brominated flame retardants and organochlorine compounds in duplicate diet samples from a Portuguese academic community.

    PubMed

    Coelho, Sónia D; Sousa, Ana C A; Isobe, Tomohiko; Kunisue, Tatsuya; Nogueira, António J A; Tanabe, Shinsuke

    2016-10-01

    Concentrations of persistent organic pollutants (POPs), including polybrominated diphenyl ethers (PBDEs), hexabromocyclododecanes (HBCDDs), polychlorinated biphenyls (PCBs), hexachlorocyclohexane isomers (HCHs), hexachlorobenzene (HCB), chlordane compounds (CHLs) and dichlorodiphenyltrichloroethane and its metabolites (DDTs), were measured in duplicate diet samples from 21 volunteers at a Portuguese academic community (University of Aveiro). Overall, the levels of the target compounds were low, with detection frequencies varying widely depending on the compounds and with brominated flame retardants (BFRs) registering the lowest detection frequencies. Among PCB congeners, nondioxin-like PCBs were predominant and detected in the majority of the samples. Organochlorine pesticides were also detected in the majority of the samples, with 100% detection for DDTs and HCHs. Estimated daily intakes (EDIs) were calculated using lower and upper bound estimations, and in both cases values were far below the currently established tolerable daily intakes for PCBs and OCs and the reference doses for PBDEs and HBCDDs.

  5. Rapid quantitative method for total brominated vegetable oil in soft drinks using ion chromatography.

    PubMed

    Yousef, Ashraf A; Abbas, Alaa B; Badawi, Bassam Sh; Al-Jowhar, Wafaa Y; Zain, Esam A; El-Mufti, Seham A

    2012-08-01

    A simple, quantitative and rapid method for total brominated vegetable oil (BVO) using ion chromatography (IC) with suppressed conductivity detection was developed and successfully applied to soft drinks with results expressed as inorganic bromide anion. The procedure involves extraction of BVO with diethyl ether and treatment with zinc dust in a solution of acetic acid, giving recoveries ranging between 92.5 and 98.5%. The calibration curves obtained were linear with correlation coefficients (r²) of 0.998, a coefficient of variation (CV) of less than 5% and limit of detection (LOD) and limit of quantification (LOQ) of 250 and 750 µg l⁻¹, respectively. The method was successfully applied to the determination of BVO in several commercial soft drinks which were found to contain BVO in the range 1.8-14.510 mg l⁻¹. The method has less sources of error compared to previously published methods.

  6. Rubber-toughened polyfunctional epoxies - Brominated vs nonbrominated formulated for graphite composites

    NASA Technical Reports Server (NTRS)

    Nir, Z.; Gilwee, W. J.; Kourtides, D. A.; Parker, J. A.

    1983-01-01

    A new, commercially available, trifunctional epoxy resin (tris-(hydroxyphenyl)-methane triglycidyl ether) was modified with synthetic rubber to increase the impact resistance of epoxy/graphite composites. These composites were reinforced with commercially available satin-weave carbon cloth using two formulations of epoxies (brominated and nonbrominated) containing various amounts of carboxy-terminated butadience acrylonitrile (CTBN) rubber that had been prereacted with epoxy resin. The impact resistance was determined by measuring the interlaminar shear strength of the composites after impact. The mechanical properties, such as flexural strength and modulus at room temperature and at 93 C, were also determined. Measurements were taken of the flammability and glass transition temperature (Tg); and a thermal-gravimetric analysis was made.

  7. Reproductive Outcomes Among Women Exposed to a Brominated Flame Retardant In Utero

    PubMed Central

    Small, Chanley M.; Murray, Deanna; Terrell, Metrecia L.; Marcus, Michele

    2014-01-01

    The authors studied 194 women exposed to polybrominated biphenyls (PBB) in utero when their mothers consumed products accidentally contaminated in Michigan in 1973. Generalized estimating equations were used to examine the effect of in utero PBB exposure on adult pregnancy-related outcomes. Compared to those with the lowest exposure (≤1 ppb), those with mid-range (>1–3.16 ppb) and high (≥3.17 ppb) PBB exposure had increased odds of spontaneous abortion with wide confidence intervals (odds ratio [OR] = 2.75, 95% confidence interval [CI] = 0.64–11.79, OR = 4.08, 95% CI = 0.94–17.70; respectively; p for trend = .05). Exposure during infancy to PBB-contaminated breast milk further increased this risk. Time to pregnancy and infertility were not associated with in utero exposure to PBB. Future studies should examine the suggested relationship between spontaneous abortion and other brominated flame retardants. PMID:22014192

  8. Seasonal surface ozone and filterable bromine relationship in the high Arctic

    NASA Astrophysics Data System (ADS)

    Oltmans, S. J.; Schnell, R. C.; Sheridan, P. J.; Peterson, R. E.; Li, S.-M.; Winchester, J. W.; Tans, P. P.; Sturges, W. T.; Kahl, J. D.; Barrie, L. A.

    Ozone and filterable bromine measurements in the high Arctic during the spring return of solar radiation suggest a rapid concurrent destruction of O 3 and conversion of gaseous to particulate Br. Multiyear observations show that this pattern is an annual feature of O 3 measured near the surface at Barrow, Alaska, and other Arctic locations. Aircraft measurements show low O 3 amounts and high filterable Br concentrations beneath the surface temperature inversion over ice throughout the Arctic in the spring. A wintertime build-up of the gaseous organic compound bromoform and a rapid depletion of bromoform in the spring may be a link between the episodic O 3 depletion events and the accompanying rise in filterable Br.

  9. Radio- and photosensitization of DNA with compounds containing platinum and bromine atoms

    NASA Astrophysics Data System (ADS)

    Śmiałek, Małgorzata A.; Ptasińska, Sylwia; Gow, Jason; Vrønning Hoffmann, Søren; Mason, Nigel J.

    2015-05-01

    Irradiations of plasmid DNA by both X-rays and UV light in the presence and absence of compounds containing platinum and bromine atoms were performed in order to asses the sensitization potential of these compounds. Plasmid DNA pBR322 was incubated with platinum (II) bromide, hydrogen hexabromoplatinate (IV), hydrogen hexahydroxyplatinate (IV) and sodium hexahydroxyplatinate (IV). Incubation was followed by X-ray or UV irradiations. It was found that amongst the sensitizers tested, during irradiations carried out in the presence of platinum (II) bromide, the highest levels of double strand breaks formation upon X-ray treatment were recorded. In contrast much less damage was induced by UV light. Data presented here suggests that this compound may be a promising radiosensitizer for cancer treatment. Contribution to the Topical Issue "COST Action Nano-IBCT: Nano-scale Processes Behind Ion-Beam Cancer Therapy", edited by Andrey Solov'yov, Nigel Mason, Gustavo García, Eugene Surdutovich.

  10. Quantitative determination of bromine and iodine in food samples using ICP-MS.

    PubMed

    Nguyen, Thi Kim Dzung; Ludwig, Rainer

    2014-01-01

    Trace concentrations of bromine and iodine in food samples and certified reference materials (CRMs) were determined by an inductively coupled plasma-mass spectrometry (ICP-MS) technique after low-power microwave digestion and extraction into an aqueous quaternary ammonium hydroxide solution. The recovery after sample preparation was quantitative. The internal standard for the measurement of the analyte on ICP-MS was optimized in this study. The detection limits were 0.19 and 0.68 ng g(-1) for I and Br, respectively, when a 10 ng g(-1) Te solution as an internal standard was used, applying the signal of (125)Te. The high recovery and reproducibility are sufficient for the quantitative analysis of these elements, and the analytical procedure is recommended for the analysis of Br and I in various kinds of bio-samples.

  11. Absolute rate of the reaction of bromine atoms with ozone from 200 to 360 K

    NASA Technical Reports Server (NTRS)

    Michael, J. V.; Lee, J. H.; Payne, W. A.; Stief, L. J.

    1978-01-01

    The rate constant for the reaction Br + O3 yields BrO + O2 has been measured from 200 to 360 K by the technique of flash photolysis coupled to time resolved detection of bromine atoms by resonance fluorescence (FP-RF). Br atoms were produced by the flash photolysis of CH3Br at a wavelength of 165 nm. O3 concentration was monitored continuously under reaction conditions by absorption at 253.7 nm. At each of five temperatures the results were independent of substantial variations in O3 concentration, total pressure (Ar), and limited variations in flash intensity (i.e., initial Br concentration). The measured rate constants obey the Arrhenius expression, k = (7.74 plus or minus 0.50) x 10 to the -12th exp(-603 plus or minus 16/T) cu cm/molecule/sec, where the error quoted is two standard deviations.

  12. Synthesis and characterization of diphenyl quinoline and bromine-activated diphenyl quinoline organic phosphors.

    PubMed

    Pimpalshende, D M; Dhoble, S J

    2014-08-01

    A diphenyl quinoline (DPQ)-conjugated derivative and bromine-activated DPQ (Br-DPQ) were synthesized in an inert gas atmosphere at 140 °C using Friedlander condensation. The compounds showed blue emission under a UV source. The structures were characterized by X-ray diffraction and Fourier transform infrared spectroscopy. The photoluminescence properties of the compounds were analysed using excitation and emission spectra. The synthesized organic phosphors shows bright emission in the blue region, with peaks at 445 and 453 nm, respectively, for DPQ and Br-DPQ in the powder form. The physical and photoluminescence properties of these organic compounds reveal promising blue emitters for high-efficiency organic light-emitting diodes.

  13. Mercury oxidation from bromine chemistry in the free troposphere over the southeastern US

    NASA Astrophysics Data System (ADS)

    Coburn, S.; Dix, B.; Edgerton, E.; Holmes, C. D.; Kinnison, D.; Liang, Q.; ter Schure, A.; Wang, S.; Volkamer, R.

    2015-10-01

    The elevated deposition of atmospheric mercury over the Southeastern United States is currently not well understood. Here we measure partial columns and vertical profiles of bromine monoxide (BrO) radicals, a key component of mercury oxidation chemistry, to better understand the processes and altitudes at which mercury is being oxidized in the atmosphere. We use the data from a ground-based MAX-DOAS instrument located at a coastal site ~ 1 km from the Gulf of Mexico in Gulf Breeze, FL, where we had previously detected tropospheric BrO (Coburn et al., 2011). Our profile retrieval assimilates information about stratospheric BrO from the WACCM chemical transport model, and uses only measurements at moderately low solar zenith angles (SZA) to estimate the BrO slant column density contained in the reference spectrum (SCDRef). The approach has 2.6 degrees of freedom, and avoids spectroscopic complications that arise at high SZA; knowledge about SCDRef helps to maximize sensitivity in the free troposphere (FT). A cloud-free case study day with low aerosol load (9 April 2010) provided optimal conditions for distinguishing marine boundary layer (MBL: 0-1 km) and free tropospheric (FT: 1-15 km) BrO from the ground. The average daytime tropospheric BrO vertical column density (VCD) of ~ 2.3 × 1013 molec cm-2 (SZA < 70°) is consistent with our earlier reports on other days. The vertical profile locates essentially all tropospheric BrO above 4 km, and shows no evidence for BrO inside the MBL (detection limit < 0.5 pptv). BrO increases in the FT. The average FT-BrO mixing ratio was ~ 0.9 pptv between 1-15 km, consistent with recent aircraft observations. We find that the oxidation of gaseous elemental mercury (GEM) by bromine radicals to form gaseous oxidized mercury (GOM) is the dominant pathway for GEM oxidation throughout the troposphere above Gulf Breeze. The column integral oxidation rates range from 3.0-3.4 × 105 molec cm-2 s-1 for bromine, while contributions from

  14. Mercury oxidation from bromine chemistry in the free troposphere over the southeastern US

    NASA Astrophysics Data System (ADS)

    Coburn, Sean; Dix, Barbara; Edgerton, Eric; Holmes, Christopher D.; Kinnison, Douglas; Liang, Qing; ter Schure, Arnout; Wang, Siyuan; Volkamer, Rainer

    2016-03-01

    The elevated deposition of atmospheric mercury over the southeastern United States is currently not well understood. Here we measure partial columns and vertical profiles of bromine monoxide (BrO) radicals, a key component of mercury oxidation chemistry, to better understand the processes and altitudes at which mercury is being oxidized in the atmosphere. We use data from a ground-based MAX-DOAS instrument located at a coastal site ˜ 1 km from the Gulf of Mexico in Gulf Breeze, FL, where we had previously detected tropospheric BrO (Coburn et al., 2011). Our profile retrieval assimilates information about stratospheric BrO from the WACCM chemical transport model (CTM), and uses only measurements at moderately low solar zenith angles (SZAs) to estimate the BrO slant column density contained in the reference spectrum (SCDRef). The approach has 2.6 degrees of freedom, and avoids spectroscopic complications that arise at high SZA; knowledge about SCDRef further helps to maximize sensitivity in the free troposphere (FT). A cloud-free case study day with low aerosol load (9 April 2010) provided optimal conditions for distinguishing marine boundary layer (MBL: 0-1 km) and free-tropospheric (FT: 1-15 km) BrO from the ground. The average daytime tropospheric BrO vertical column density (VCD) of ˜ 2.3 × 1013 molec cm-2 (SZA < 70°) is consistent with our earlier reports on other days. The vertical profile locates essentially all tropospheric BrO above 4 km, and shows no evidence for BrO inside the MBL (detection limit < 0.5 pptv). BrO increases to ˜ 3.5 pptv at 10-15 km altitude, consistent with recent aircraft observations. Our case study day is consistent with recent aircraft studies, in that the oxidation of gaseous elemental mercury (GEM) by bromine radicals to form gaseous oxidized mercury (GOM) is the dominant pathway for GEM oxidation throughout the troposphere above Gulf Breeze. The column integral oxidation rates are about 3.6 × 105 molec cm-2 s-1 for bromine

  15. Responses of marine unicellular algae to brominated organic compounds in six growth media

    SciTech Connect

    Walsh, G.E.; Yoder, M.J.; McLaughlin, L.L.; Lores, E.M.

    1987-12-01

    Marine unicellular algae, Skeletonema costatum, Thalassiosira pseudonana, and Chlorella sp. were exposed to the industrial brominated compounds tetrabromobisphenol A, decabromobiphenyloxide (DBBO), hexabromocyclododecane (HBCD), pentabromomethylbenzene (PBMB), pentabromoethylbenzene (PBEB), and the herbicide bromoxynil (BROM), in six algal growth media. High concentrations of DBBO (1 mg liter-1), PBMB (1 mg liter-1), and PBEB (0.5 mg liter-1) reduced growth by less than 50%. EC50s of the other compounds varied with growth medium, with high EC50/low EC50 ratios between 1.3 and 9.9. Lowest EC50s, 9.3 to 12.0 micrograms liter-1, were obtained with S. costatum and HBCD. It is concluded that responses to toxicants in different media are the results of interactions among algae, growth medium, toxicant, and solvent carrier.

  16. Fertilizer nitrogen isotope signatures.

    PubMed

    Bateman, Alison S; Kelly, Simon D

    2007-09-01

    There has been considerable recent interest in the potential application of nitrogen isotope analysis in discriminating between organically and conventionally grown crops. A prerequisite of this approach is that there is a difference in the nitrogen isotope compositions of the fertilizers used in organic and conventional agriculture. We report new measurements of delta15N values for synthetic nitrogen fertilizers and present a compilation of the new data with existing literature nitrogen isotope data. Nitrogen isotope values for fertilizers that may be permitted in organic cultivation systems are also reported (manures, composts, bloodmeal, bonemeal, hoof and horn, fishmeal and seaweed based fertilizers). The delta15N values of the synthetic fertilizers in the compiled dataset fall within a narrow range close to 0 per thousand with 80% of samples lying between-2 and 2 per thousand and 98.5% of the data having delta15N values of less than 4 per thousand (mean=0.2 per thousand n=153). The fertilizers that may be permitted in organic systems have a higher mean delta15N value of 8.5 per thousand and exhibit a broader range in delta15N values from 0.6 to 36.7 per thousand (n=83). The possible application of the nitrogen isotope approach in discriminating between organically and conventionally grown crops is discussed in light of the fertilizer data presented here and with regard to other factors that are also important in determining crop nitrogen isotope values.

  17. Deposition of brominated flame retardants to the Devon Ice Cap, Nunavut, Canada.

    PubMed

    Meyer, Torsten; Muir, Derek C G; Teixeira, Camilla; Wang, Xiaowa; Young, Teresa; Wania, Frank

    2012-01-17

    Brominated flame retardants (BFRs) can be transported to Arctic regions via atmospheric long-range transport, however, relatively little is known about their deposition to terrestrial environments. Snow cores from the Devon Ice Cap in Nunavut, Canada served to determine the recent depositional trends of BFRs. Snow pits were dug in 2005, 2006, and 2008. Dating using annual snow accumulation data, ion chemistry, and density measurements established that the pits covered the period from approximately 1993 to spring 2008. Samples were extracted under clean room conditions, and analyzed using GC-negative ion MS for 26 tri- to decabromodiphenyl ethers (BDEs), as well as other BFRs, nonbrominated flame retardants, and industrial chemicals. Decabromodiphenyl ether (BDE-209) was the major congener present in all samples followed by nona-BDEs (BDE-207, BDE-206, and BDE-208), both accounting for 89% and 7% of total BDE, respectively. BDE-209 concentrations were in most cases significantly correlated (P < 0.05) to tri- to nona-BDE homologues, and the strength of the correlations increased with increasing degree of bromination. Prior to or after deposition BDE-209 may be subject to debromination to lighter congeners. Deposition fluxes of BDE-209 show no clear temporal trend and range between 90 and 2000 pg·cm(-2)·year(-1). Back trajectory origin in densely populated areas of northeastern North America is significantly correlated (P < 0.005) with the BDE-209 deposition flux. Several other high production volume and/or alternative BFRs such as hexabromocyclododecane (HBCD), 1,2-bis(2,4,6-dibromophenoxy)ethane (BTBPE), pentabromo ethyl benzene (PBEBz), and pentabromobenzene (PBBz), as well as the industrial chemical 1,3,5-tribromobenzene (135-TBBz) were found consistently in the snow pits.

  18. Co-leaching of brominated compounds and antimony from bottled water.

    PubMed

    Andra, Syam S; Makris, Konstantinos C; Shine, James P; Lu, Chensheng

    2012-01-01

    A fast-growing bottled water market is occasionally challenged by reports calling for contaminant leaching from water-contact materials (plastics). Our focus was on leaching of antimony (Sb) and brominated compounds expressed by total soluble bromine (Br) measurements, including those of polybrominated diphenyl ethers (PBDE). Studies are lacking on concomitant leaching of two or more inorganic plastic constituents from the same bottle. A market-representative basket survey of bottled water was initiated in Boston, USA supermarkets. Bottled water classes sampled were: i) non-carbonated (NCR), ii) carbonated (CR), and iii) non-carbonated and enriched (NCRE). Plastic bottle materials sampled were: polyethylene terephthalate (PET), high-density polyethylene (HDPE), polystyrene (PS), and polycarbonate (PC). Storage conditions for the 31 bottled water samples were: 23°C temperature, no-shaking and 12h/12h light/dark for 60days of equilibration. Average Br and Sb concentrations after 60-days of storage followed the order of NCR

  19. Modeling brominated trihalomethane compounds in drinking water at a treatment plant in Beaumont, Texas.

    PubMed

    Chaib, Embarka; Moschandreas, Demetrios

    2006-01-01

    The premise of this study is that the presence of bromide has a substantial effect on both the speciation and total formation of trihalomethane (THM). Consequently, models of water containing substantial bromide concentrations require refinement because they are only calibrated with raw water with high humic acid content. This study investigates and reports efforts on such refinement. The objectives of work reported in this paper are to formulate and validate a new correlative model that is based on physical principles and incorporates high levels of bromide that affect THM formation using raw water rich in both humic and fulvic acid. Two types of THM precursors are considered in the model discussed in this paper: (1) activated aromatic groups, which are more reactive with chlorine than with bromine, and (2) aliphatic groups, which are more reactive with bromine than with chlorine. Aliphatic and aromatic carbons are incorporated in the model by the inclusion of pertinent variables such as C/N and Br/Cl2 in the algorithm. The model also includes NH4+. This variable affects chlorine consumption that, in turn, potentially affects THM formation. For the first time ever, organic carbon to organic nitrogen and bromide to chlorine ratios is also used as variables potentially affecting THM formation when treating drinking water. The THM model formulated in this paper is an empirical model based on scientific principles and not simply a regression equation. The formulated model is pronounced valid based on a validation effort that employs a portion of an EPA database that was not used for model formulation.

  20. Levels of brominated flame retardants (BFRs) in honey samples from different geographic regions.

    PubMed

    Mohr, Susana; García-Bermejo, Angel; Herrero, Laura; Gómara, Belén; Costabeber, Ijoni Hilda; González, María José

    2014-02-15

    Concentrations of 17 brominated flame retardants (BFRs), including two "novel" BFRs (1,2-bis(2,4,6-tribromophenoxy)ethane, BTBPE and decabromodiphenylethane, DBDPE), have been determined to be in 35 commercial honey samples from Brazil, Spain, Portugal, Slovenia and Morocco. The results revealed the presence of low amounts (betweenbrominated PBDEs, principally BDE-47, found in honey samples from Slovenia, Spain and Portugal. Meanwhile the most abundant BFRs found in Brazilian and Moroccan honeys were the two novel BFRs (BTBPE and DBDPE). The detection of BFRs in honeys from different countries highlights the risk that their presence poses to the health of humans and wildlife since honey is a non-fatty natural product that is highly consumed all over the world.

  1. Brominated organic contaminants in the liver and egg of the common cormorants (Phalacrocorax carbo) from Japan.

    PubMed

    Watanabe, Kiyohiko; Senthilkumar, Kurunthachalam; Masunaga, Shigeki; Takasuga, Takumi; Iseki, Naomasa; Morita, Masatoshi

    2004-08-01

    The contamination profiles of brominated flame retardants (BFRs) such as polybrominated diphenyl ethers (PBDEs), biphenyls (PBBs), dibenzo-p-dioxins (PBDDs), and dibenzofurans (PBDFs) were determined in the liver and egg of common cormorants from Japan. PBDEs and PBBs were detected in all the samples; especially the former were detected at elevated levels. PBDDs/PBDFs were also detected in cormorants, albeit the concentrations were lower than those of the PBBs. The total concentration of PBDEs ranged from 330 to 2600 in the liver and from 600 to 3300 in the egg on a nanogram per gram of lipid basis. The concentration of PBBs was in the range from 3.0 to 33 (in the liver) and from 3.4 to 82 (in the egg) on a nanogram per gram of lipid basis. The 2,2',4,4',5,5'-hexabromobiphenyl (BB-153) was the most predominant PBB congener in either organ, which corresponds to a major constituent of the BFR FireMaster BP-6. Concentrations of PBDDs/ PBDFs in the liver (range from 21 to 470) were slightly higher than in the egg (range from 31 to 160) on a picogram per gram of lipid basis. The results of this study imply that common cormorants accumulate a high level of PBDEs and PBBs. Comparing the concentrations of brominated organic compounds with those of chlorinated analogues, good relevance between PBBs and coplanar PCBs (r2 = 0.746 [liver] and 0.715 [egg]) was elucidated. To our knowledge, the present study demonstrates the first report of PBDEs, PBBs, and PBDDs/PBDFs in the common cormorant from Japan.

  2. Electrospun Nafion®/Polyphenylsulfone composite membranes for regenerative Hydrogen bromine fuel cells

    SciTech Connect

    Park, Jun; Wycisk, Ryszard; Pintauro, Peter N.; Yarlagadda, Venkata; Van Nguyen, Trung

    2016-02-29

    Here, the regenerative H2/Br2-HBr fuel cell, utilizing an oxidant solution of Br2 in aqueous HBr, shows a number of benefits for grid-scale electricity storage. The membrane-electrode assembly, a key component of a fuel cell, contains a proton-conducting membrane, typically based on the perfluorosulfonic acid (PFSA) ionomer. Unfortunately, the high cost of PFSA membranes and their relatively high bromine crossover are serious drawbacks. Nanofiber composite membranes can overcome these limitations. In this work, composite membranes were prepared from electrospun dual-fiber mats containing Nafion® PFSA ionomer for facile proton transport and an uncharged polymer, polyphenylsulfone (PPSU), for mechanical reinforcement, and swelling control. After electrospinning, Nafion/PPSU mats were converted into composite membranes by softening the PPSU fibers, through exposure to chloroform vapor, thus filling the voids between ionomer nanofibers. It was demonstrated that the relative membrane selectivity, referenced to Nafion® 115, increased with increasing PPSU content, e.g., a selectivity of 11 at 25 vol% of Nafion fibers. H2-Br2 fuel cell power output with a 65 m thick membrane containing 55 vol% Nafion fibers was somewhat better than that of a 150 m Nafion® 115 reference, but its cost advantage due to a four-fold decrease in PFSA content and a lower bromine species crossover make it an attractive candidate for use in H2/Br2-HBr systems.

  3. Meteorological controls on the vertical distribution of bromine monoxide in the lower troposphere

    NASA Astrophysics Data System (ADS)

    Peterson, P. K.; Simpson, W. R.; Pratt, K. A.; Shepson, P. B.; Frieß, U.; Zielcke, J.; Platt, U.; Walsh, S. J.; Nghiem, S. V.

    2014-09-01

    Multiple axis differential absorption spectroscopy (MAX-DOAS) measurements of bromine monoxide (BrO) probed the vertical structure of halogen activation events during March-May 2012 at Barrow, Alaska. An analysis of the BrO averaging kernels and degrees of freedom obtained by optimal-estimation-based inversions from raw MAX-DOAS measurements reveals the information is best represented by reducing the retrieved BrO profile to two quantities, the integrated column from the surface through 200 m (VCD200 m), and the lower tropospheric vertical column density (LT-VCD) which represents the integrated column of BrO from the surface through 2 km. The percentage of lower-tropospheric BrO in the lowest 200 m was found to be highly variable ranging from shallow layer events, where BrO is present primarily in the lowest 200 m to distributed column events where BrO is observed at higher altitudes. The highest observed LT-VCD events occurred when BrO was distributed throughout the lower troposphere, rather than concentrated near the surface. Atmospheric stability in the lowest 200 m influenced the percentage of LT-VCD that is in the lowest 200 m, with inverted temperature structures having a first-to-third quartile range (Q1-Q3) of VCD200 m/LT-VCD from 15-39% while near neutral temperature structures had a Q1-Q3 range of 7-13%. Data from this campaign show no clear influence of wind speed on either lower-tropospheric bromine activation (LT-VCD) or the vertical distribution of BrO, while examination of seasonal trends and the temperature dependence of the vertical distribution supported the conclusion that the atmospheric stability affects the vertical distribution of BrO.

  4. Laser Ablation Molecular Isotopic Spectrometry: Strontium and its isotopes

    NASA Astrophysics Data System (ADS)

    Mao, Xianglei; Bol'shakov, Alexander A.; Choi, Inhee; McKay, Christopher P.; Perry, Dale L.; Sorkhabi, Osman; Russo, Richard E.

    2011-11-01

    The experimental details are reported of Laser Ablation Molecular Isotopic Spectrometry (LAMIS) and its application for performing optical isotopic analysis of solid strontium-containing samples in ambient atmospheric air at normal pressure. The LAMIS detection method is described for strontium isotopes from samples of various chemical and isotopic compositions. The results demonstrate spectrally resolved measurements of the three individual 86Sr, 87Sr, and 88Sr isotopes that are quantified using multivariate calibration of spectra. The observed isotopic shifts are consistent with those calculated theoretically. The measured spectra of diatomic oxide and halides of strontium generated in laser ablation plasmas demonstrate the isotopic resolution and capability of LAMIS. In particular, emission spectra of SrO and SrF molecular radicals provided clean and well resolved spectral signatures for the naturally occurring strontium isotopes. A possibility is discussed of using LAMIS of strontium isotopes for radiogenic age determination.

  5. Oxygen Isotopes in Meteorites

    NASA Astrophysics Data System (ADS)

    Clayton, R. N.

    2003-12-01

    Oxygen isotope abundance variations in meteorites are very useful in elucidating chemical and physical processes that occurred during the formation of the solar system (Clayton, 1993). On Earth, the mean abundances of the three stable isotopes are 16O: 99.76%, 17O: 0.039%, and 18O: 0.202%. It is conventional to express variations in abundances of the isotopes in terms of isotopic ratios, relative to an arbitrary standard, called SMOW (for standard mean ocean water), as follows:The isotopic composition of any sample can then be represented by one point on a "three-isotope plot," a graph of δ17O versus δ18O. It will be seen that such plots are invaluable in interpreting meteoritic data. Figure 1 shows schematically the effect of various processes on an initial composition at the center of the diagram. Almost all terrestrial materials lie along a "fractionation" trend; most meteoritic materials lie near a line of "16O addition" (or subtraction). (4K)Figure 1. Schematic representation of various isotopic processes shown on an oxygen three-isotope plot. Almost all terrestrial materials plot along a line of "fractionation"; most primitive meteoritic materials plot near a line of "16O addition." The three isotopes of oxygen are produced by nucleosynthesis in stars, but by different nuclear processes in different stellar environments. The principal isotope, 16O, is a primary isotope (capable of being produced from hydrogen and helium alone), formed in massive stars (>10 solar masses), and ejected by supernova explosions. The two rare isotopes are secondary nuclei (produced in stars from nuclei formed in an earlier generation of stars), with 17O coming primarily from low- and intermediate-mass stars (<8 solar masses), and 18O coming primarily from high-mass stars (Prantzos et al., 1996). These differences in type of stellar source result in large observable variations in stellar isotopic abundances as functions of age, size, metallicity, and galactic location ( Prantzos

  6. Physicochemical isotope anomalies

    SciTech Connect

    Esat, T.M.

    1988-06-01

    Isotopic composition of refractory elements can be modified, by physical processes such as distillation and sputtering, in unexpected patterns. Distillation enriches the heavy isotopes in the residue and the light isotopes in the vapor. However, current models appear to be inadequate to describe the detailed mass dependence, in particular for large fractionations. Coarse- and fine-grained inclusions from the Allende meteorite exhibit correlated isotope effects in Mg both as mass-dependent fractionation and residual anomalies. This isotope pattern can be duplicated by high temperature distillation in the laboratory. A ubiquitous property of meteoritic inclusions for Mg as well as for most of the other elements, where measurements exist, is mass-dependent fractionation. In contrast, terrestrial materials such as microtektites, tektite buttons as well as lunar orange and green glass spheres have normal Mg isotopic composition. A subset of interplanetary dust particles labelled as chondritic aggregates exhibit excesses in {sup 26}Mg and deuterium anomalies. Sputtering is expected to be a dominant mechanism in the destruction of grains within interstellar dust clouds. An active proto-sun as well as the present solar-wind and solar-flare flux are of sufficient intensity to sputter significant amounts of material. Laboratory experiments in Mg show widespread isotope effects including residual {sup 26}Mg excesses and mass dependent fractionation. It is possible that the {sup 26}Mg excesses in interplanetary dust is related to sputtering by energetic solar-wind particles. The implication if the laboratory distillation and sputtering effects are discussed and contrasted with the anomalies in meteoritic inclusions the other extraterrestrial materials the authors have access to.

  7. Cyanocarbon acids: direct evidence that their ionization is not an encounter-controlled process and rationalization of the unusual solvent isotope effects

    SciTech Connect

    Hojatti, M.; Kresge, A.J.; Wang, W.H.

    1987-06-24

    The rate of exchange of the acidic hydrogen of tert-butylmalononitrile was examined by using tritium as a tracer, and the process was found not to be inhibited by hydronium ions in dilute aqueous hydrochloric acid solutions. This rules out the Swain-Grunwald mechanism for this reaction under these conditions. The bromination of malononitrile was investigated under conditions where reprotonation of the dicyanomethyl carbanion and its reaction with bromine occur at comparable rates, and the bromination reaction was found to have a specific rate twice that for reprotonation. Reprotonation therefore cannot be a diffusion-controlled process, and malononitrile is not a normal acid. The unusually large solvent kinetic isotope effects found for these cyanocarbon acid ionization reactions are explained by postulating that the transferring hydrogen and its positive charge are becoming associated with a solvent cluster rather than with a single water molecule. The thermodynamic acidity constant of malononitrile was determined to be 11.41 in aqueous solution at 25 C.

  8. Separation of sulfur isotopes

    DOEpatents

    DeWitt, Robert; Jepson, Bernhart E.; Schwind, Roger A.

    1976-06-22

    Sulfur isotopes are continuously separated and enriched using a closed loop reflux system wherein sulfur dioxide (SO.sub.2) is reacted with sodium hydroxide (NaOH) or the like to form sodium hydrogen sulfite (NaHSO.sub.3). Heavier sulfur isotopes are preferentially attracted to the NaHSO.sub.3, and subsequently reacted with sulfuric acid (H.sub.2 SO.sub.4) forming sodium hydrogen sulfate (NaHSO.sub.4) and SO.sub.2 gas which contains increased concentrations of the heavier sulfur isotopes. This heavy isotope enriched SO.sub.2 gas is subsequently separated and the NaHSO.sub.4 is reacted with NaOH to form sodium sulfate (Na.sub.2 SO.sub.4) which is subsequently decomposed in an electrodialysis unit to form the NaOH and H.sub.2 SO.sub.4 components which are used in the aforesaid reactions thereby effecting sulfur isotope separation and enrichment without objectionable loss of feed materials.

  9. Transportation of medical isotopes

    SciTech Connect

    Nielsen, D.L.

    1997-11-19

    A Draft Technical Information Document (HNF-1855) is being prepared to evaluate proposed interim tritium and medical isotope production at the Fast Flux Test Facility (FFTF). This assessment examines the potential health and safety impacts of transportation operations associated with the production of medical isotopes. Incident-free and accidental impacts are assessed using bounding source terms for the shipment of nonradiological target materials to the Hanford Site, the shipment of irradiated targets from the FFTF to the 325 Building, and the shipment of medical isotope products from the 325 Building to medical distributors. The health and safety consequences to workers and the public from the incident-free transportation of targets and isotope products would be within acceptable levels. For transportation accidents, risks to works and the public also would be within acceptable levels. This assessment is based on best information available at this time. As the medical isotope program matures, this analysis will be revised, if necessary, to support development of a final revision to the Technical Information Document.

  10. Isotope geochemistry. Biological signatures in clumped isotopes of O₂.

    PubMed

    Yeung, Laurence Y; Ash, Jeanine L; Young, Edward D

    2015-04-24

    The abundances of molecules containing more than one rare isotope have been applied broadly to determine formation temperatures of natural materials. These applications of "clumped" isotopes rely on the assumption that isotope-exchange equilibrium is reached, or at least approached, during the formation of those materials. In a closed-system terrarium experiment, we demonstrate that biological oxygen (O2) cycling drives the clumped-isotope composition of O2 away from isotopic equilibrium. Our model of the system suggests that unique biological signatures are present in clumped isotopes of O2—and not formation temperatures. Photosynthetic O2 is depleted in (18)O(18)O and (17)O(18)O relative to a stochastic distribution of isotopes, unlike at equilibrium, where heavy-isotope pairs are enriched. Similar signatures may be widespread in nature, offering new tracers of biological and geochemical cycling.

  11. Flame retardant brominated styrene-based polymers. II. Synthesis, characterization and application of dibromostyrene, styrene and butadiene terpolymers

    SciTech Connect

    Wang, J.L.; Favstritsky, N.A.

    1993-12-31

    Brominated styrene-based polymers having surprisingly good physical properties in combination with flame retardancy are prepared from terpolymers of dibromostyrene, styrene and butadiene. Polymerization compositions were determined by bromine contents (% Br) of the polymers by Schoeninger Combustion Method and {sup 1}H NMR integration. Weight losses (% loss) were measured at 20{degrees}C/min by Thermogravimetric Analysis (TGA). Molecular weights were measured by GPC based on a standard molecular weight (MW) of polystyrene (PS)> Flammability of the latex products when used in textile backcoatings was testing by Motor Vehicle Safety Standard 302 (MVSS-302) flammability test. As latexes were used as non-woven binders, flammability was tested by exposure to a 4 in high, 1950{degrees}F propane flame from a Fisher Burner. When latexes were employed for carpet backing, flammability was tested by DOC. FF-1-70 (pill test) flammability tests.

  12. Bromine is an essential trace element for assembly of collagen IV scaffolds in tissue development and architecture.

    PubMed

    McCall, A Scott; Cummings, Christopher F; Bhave, Gautam; Vanacore, Roberto; Page-McCaw, Andrea; Hudson, Billy G

    2014-06-05

    Bromine is ubiquitously present in animals as ionic bromide (Br(-)) yet has no known essential function. Herein, we demonstrate that Br(-) is a required cofactor for peroxidasin-catalyzed formation of sulfilimine crosslinks, a posttranslational modification essential for tissue development and architecture found within the collagen IV scaffold of basement membranes (BMs). Bromide, converted to hypobromous acid, forms a bromosulfonium-ion intermediate that energetically selects for sulfilimine formation. Dietary Br deficiency is lethal in Drosophila, whereas Br replenishment restores viability, demonstrating its physiologic requirement. Importantly, Br-deficient flies phenocopy the developmental and BM defects observed in peroxidasin mutants and indicate a functional connection between Br(-), collagen IV, and peroxidasin. We establish that Br(-) is required for sulfilimine formation within collagen IV, an event critical for BM assembly and tissue development. Thus, bromine is an essential trace element for all animals, and its deficiency may be relevant to BM alterations observed in nutritional and smoking-related disease. PAPERFLICK:

  13. Isotope separation apparatus

    DOEpatents

    Arnush, Donald; MacKenzie, Kenneth R.; Wuerker, Ralph F.

    1980-01-01

    Isotope separation apparatus consisting of a plurality of cells disposed adjacent to each other in an evacuated container. A common magnetic field is established extending through all of the cells. A source of energetic electrons at one end of the container generates electrons which pass through the cells along the magnetic field lines. Each cell includes an array of collector plates arranged in parallel or in tandem within a common magnetic field. Sets of collector plates are disposed adjacent to each other in each cell. Means are provided for differentially energizing ions of a desired isotope by applying energy at the cyclotron resonant frequency of the desired isotope. As a result, the energized desired ions are preferentially collected by the collector plates.

  14. Deuterium isotope effect on the induction period of the cerium catalyzed Belousov-Zhabotinsky reaction

    NASA Astrophysics Data System (ADS)

    Rossi, Federico; Simoncini, Eugenio; Marchettini, Nadia; Tiezzi, Enzo

    2009-02-01

    In this work we present results about the deuterium isotopic effect on the global kinetics of a cerium catalyzed Belousov-Zhabotinsky reaction. A nonlinear dependence of the induction period upon the percentage of deuterated reactants was found in batch conditions. In order to understand this result, we investigated two reaction pathways responsible for the length of the induction period, namely: (a) the reaction between the enolic form of the malonic acid with molecular bromine and (b) the oxidation of malonic acid by the Ce(IV) ion. In both cases we obtained a linear dependence of the kinetic constants on the percentage of deuterated reactants. Nevertheless, by inserting the experimental values in the MBM (Marburg-Budapest-Missoula) model, we were able to qualitatively simulate the observed trend of the induction period.

  15. Release of gaseous bromine from the photolysis of nitrate and hydrogen peroxide in simulated sea-salt solutions

    NASA Astrophysics Data System (ADS)

    George, Ingrid J.; Anastasio, Cort

    We have carried out a series of laboratory experiments to investigate the oxidation of bromide (Br -) by hydroxyl radical ( rad OH) in solutions used to mimic sea-salt particles. Aqueous halide solutions with nitrate or hydrogen peroxide (HOOH) as a photochemical source of rad OH were illuminated with 313 nm light and the resulting gaseous bromine (Br*(g)) was collected. While illumination of these solutions nearly always formed gaseous bromine (predominantly Br 2 based on modeling results), there was no evidence for the release of gaseous chlorine. The rate of Br*(g) release increased (up to a plateau value) with increasing concentrations of bromide and was enhanced at lower pH values for both nitrate and HOOH solutions. Increased ionic strength in nitrate solutions inhibited Br*(g) release and the extent of inhibition was dependent upon the salt used. In HOOH solutions, however, no ionic strength effects were observed and the presence of Cl - strongly enhanced Br*(g) release. Overall, for conditions typical of aged, deliquesced, sea-salt particles, the efficiencies of gaseous bromine release, expressed as mole of Br*(g) released per mole of rad OH photochemically formed, were typically 20-30%. Using these reaction efficiencies, we calculated the Br 2(g) release rate from aged, ambient sea-salt particles due to rad OH oxidation to be approximately 0.07 pptv h -1 with the main contributions from nitrate photolysis and partitioning of gas-phase rad OH into the particle. While our solution conditions are simplified compared to ambient particles, this estimated rate of Br 2 release is high enough to suggest that rad OH-mediated reactions in sea-salt particles could be a significant source of reactive bromine to the marine boundary layer.

  16. Volcanic degassing of bromine and iodine: experimental fluid/melt partitioning data and applications to stratospheric chemistry

    NASA Astrophysics Data System (ADS)

    Bureau, Hélène; Keppler, Hans; Métrich, Nicole

    2000-11-01

    In order to understand the degassing behavior of heavy halogens in volcanic processes, we experimentally studied the distribution of Cl, Br, and I between albite melt and hydrous fluids containing 0.01-2 wt% of NaCl, NaBr, or NaI, respectively. All experiments were carried out at 2 kbar and 900°C in rapid-quench cold-seal autoclaves with a run duration of 7 days. The major element compositions and Cl contents of the glassy run products were measured by electron microprobe. Bromine and iodine were measured by proton-induced X-ray emission. Fluid compositions were obtained by mass balance. All halogens investigated were found to partition strongly into the fluid phase. Over the range of concentrations studied, the halogen contents in the melt are proportional to the concentrations in the fluid. The fluid/melt partition coefficients, Df/m, are 8.1±0.2 for Cl, 17.5±0.6 for Br, and 104±7 for I. The logarithm of Df/m is linearly correlated with the ionic radius of the halogenide ion. On the basis of our experimental data, we estimate the amount of bromine injected into the stratosphere by major volcanic explosions. For the 1991 Mount Pinatubo eruption, we obtain Br yields of 11-25 kt as minimum estimates. These numbers are comparable to the total annual influx of bromine into the stratosphere from all other natural and anthropogenic sources (about 100 kt/year). Since bromine is much more efficient in destroying stratospheric ozone than chlorine, it could at least be partially responsible for the massive ozone depletion observed after the 1991 Mount Pinatubo eruption.

  17. An investigation into the sensitivity of the atmospheric chlorine and bromine loading using a globally averaged mass balance model

    NASA Astrophysics Data System (ADS)

    Dowdell, David C.; Matthews, G. Peter; Wells, Ian

    Two globally averaged mass balance models have been developed to investigate the sensitivity and future level of atmospheric chlorine and bromine as a result of the emission of 14 chloro- and 3 bromo-carbons. The models use production, growth, lifetime and concentration data for each of the halocarbons and divide the production into one of eight uses, these being aerosol propellants, cleaning agents, blowing agents in open and closed cell foams, non-hermetic and hermetic refrigeration, fire retardants and a residual "other" category. Each use category has an associated emission profile which is built into the models to take into account the proportion of halocarbon retained in equipment for a characteristic period of time before its release. Under the Montreal Protocol 3 requirements, a peak chlorine loading of 3.8 ppb is attained in 1994, which does not reduce to 2.0 ppb (the approximate level of atmospheric chlorine when the ozone hole formed) until 2053. The peak bromine loading is 22 ppt, also in 1994, which decays to 12 ppt by the end of next century. The models have been used to (i) compare the effectiveness of Montreal Protocols 1, 2 and 3 in removing chlorine from the atmosphere, (ii) assess the influence of the delayed emission assumptions used in these models compared to immediate emission assumptions used in previous models, (iii) assess the relative effect on the chlorine loading of a tightening of the Montreal Protocol 3 restrictions, and (iv) calculate the influence of chlorine and bromine chemistry as well as the faster phase out of man-made methyl bromide on the bromine loading.

  18. M1 decay of the 2 sup 3 S sub 1 state of helium-like bromine

    SciTech Connect

    Dunford, R.W.; Liu, C.J.; Berry, H.G.; Raphaelian, M.L.A. ); Church, D.A. ); Hass, M. ); Curtis, L.J. )

    1990-01-01

    We have measured the lifetime of the 2 {sup 3}S{sub 1} level in helium-like bromine with the results {tau}{sup exp}(2 {sup 3}S{sub 1}) = 224.1 (7.1) ps, in agreement with theory. Our error is dominated by uncertainties in the correction for the effects of cascades from highly excited states. 7 refs., 1 fig.

  19. [Formation of disinfection by-products by Microcystis aeruginosa intracellular organic matter: comparison between chlorination and bromination].

    PubMed

    Tian, Chuan; Guo, Ting-Ting; Liu, Rui-Ping; Jefferson, William; Liu, Hui-Juan; Qu, Jiu-Hui

    2013-11-01

    In order to illustrate the effects of released algal organic matter in cyanobacteria blooms on raw water quality and water treatment process, intracellular organic matter (IOM) of Microcystis aeruginosa, which is the dominant species in cyanobacteria blooms, was chosen as a precursor and characterized. In addition, the transformation of IOM and the formation of disinfection byproducts were evaluated at different pH of 6.5, 7.1 and 8.4 after chlorination or bromination, with subsequent correlation analysis. The results indicated that IOM was primarily composed of macromolecular matter, i. e. , the species with relative molecular weight of > 30 x 10(3), constituting 68.8% of dissolved organic carbon (DOC). Fluorescence excitation-emission matrix indicated that IOM was mainly composed of aromatic protein-like matter with an intensity of 92.6 AU x L x mg(-1). After reaction with chlorine or bromine, the intensity of aromatic protein-like peaks decreased sharply by 76.6% - 93.3%, and its reduction correlated well with the formation of trihalomethane (THMs, R2 = 0.81) and haloacetic acid (HAAs, R2 = 0.77). The formation of THMs and HAAs increased with the increase in pH. Compared with chlorine, bromine formed more THMs and HAAs, and tended to form highly halogenated HAAs. However, with increasing pH, the reactivity with IOM between chlorine and bromine was closer, i.e, k(OBr-IOM)/k(OCl-(IOM) < k(HOBr-IOM/k(HOCl-IOM).

  20. The mercury species and their association with carbonaceous compositions, bromine and iodine in PM2.5 in Shanghai.

    PubMed

    Duan, Lian; Xiu, Guangli; Feng, Ling; Cheng, Na; Wang, Chenggang

    2016-03-01

    PM2.5 samples were collected in south Shanghai from November 2013 to October 2014. The species of particulate bounded mercury (PBM), including hydrochloric soluble particle-phase mercury (HPM), element soluble particle-phase mercury (EPM) and residual soluble particle-phase mercury (RPM), were determined in PM2.5. The chemical composition of PM2.5 including organic carbon (OC) and elemental carbon (EC), total bromine and iodine were also analyzed. The results showed that the annual average concentration of PBM was 0.30 ± 0.31 ng m(-3) and 0.34 ± 0.32 ng m(-3) in winter, 0.31 ± 0.19 ng m(-3) in spring, 0.30 ± 0.45 ng m(-3) in fall and 0.28 ± 0.17 ng m(-3) in summer. HPM took the highest fraction 51.2% in PBM, followed by RPM 27.7% and EPM 21.1%. EC positively correlated to particle mercury, especially in winter (r = 0.70), the same for OC in winter (r = 0.72), which indicated that the carbonaceous composition may affect the transformation of Hg in the atmosphere. Mercury species showed different correlations with bromine and iodine in the four seasons. The strongest correlation between bromine, iodine and mercury was found in spring and fall, respectively. Bromine showed the stronger correlation with total mercury and speciated particle mercury than iodine. In addition, the days were classified into haze and non-haze days based on the visibility and relative humidity, while the ratio of HPM in haze days was much higher than that in non-haze days. EC strongly correlated with PBM during haze and non-haze days while OC only positively correlated with PBM in non-haze days, this may indicate that the different carbonaceous part may affect PBM differently.