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Sample records for ammonium uranyl carbonates

  1. Alternative process to produce UF{sub 4} using the effluent from ammonium uranyl carbonate route

    Energy Technology Data Exchange (ETDEWEB)

    Silva Neto, Joao B.; Garcia, Rafael Henrique Lazzari; Dal Vechio, Edvaldo, E-mail: jbsneto@ipen.br [Instituto de Pesquisas Energeticas e Nucleares (IPEN/CNEN-SP), SP (Brazil); Riella, Humberto G., E-mail: riella@enq.ufsc.br [Universidade Federal de Santa Catarina (UFSC), Florianopolis, SC (Brazil); Instituto Nacional de Ciencias e Tecnologia de Reatores Nucleares Inovadores (INCT/CNPq) (Brazil); Carvalho, Elita F. Urano de; Durazzo, Michelangelo [Instituto de Pesquisas Energeticas e Nucleares (IPEN/CNEN-SP), SP (Brazil); Instituto Nacional de Ciencias e Tecnologia de Reatores Nucleares Inovadores (INCT/CNPq) (Brazil)

    2011-07-01

    The Nuclear Fuel Centre of IPEN / CNEN - SP develops and manufactures dispersion fuel with high uranium concentration. It meets the demand of the IEA-R1 reactor and future research reactors to be constructed in Brazil. The fuel uses uranium silicide (U{sub 3}Si{sub 2}) dispersed in aluminum. For producing the fuel, the process of uranium hexafluoride (UF{sub 6}) conversion consist in obtaining U{sub 3}Si{sub 2} and / or U{sub 3}O{sub 8} through the preparation of intermediate compounds, among them ammonium uranyl carbonate - AUC, ammonium diuranate - DUA and uranium tetrafluoride - UF{sub 4}. This work describes a procedure for preparing uranium tetrafluoride via a dry route, using as raw material the filtrate generated when ammonium uranyl carbonate is routinely produced. The filtrate consists mainly of a solution containing high concentrations of ammonium (NH{sup 4+}), fluoride (F{sup -}), carbonate (CO{sup 3-}) and low concentrations of uranium. The procedure consists in recovering NH{sup 4F} and uranium, as UF{sub 4}, through the crystallization of ammonium bifluoride (NH{sub 4}HF{sub 2}) and, in a later step, the addition of UO{sub 2}, occurring fluoridation and decomposition. The UF{sub 4} obtained is further diluted in the UF{sub 4} produced routinely at IPEN / CNEN-SP by a wet route process. (author)

  2. Thermal Analysis of the Decomposition of Ammonium Uranyl Carbonate (AUC) in Different Atmospheres

    DEFF Research Database (Denmark)

    Hälldahl, L.; Sørensen, Ole Toft

    1979-01-01

    The intermediate products formed during thermal decomposition of ammonium uranyl carbonate (AUC) in different atmospheres, (air, helium and hydrogen) have been determined by thermal analysis, (TG, and DTA) and X-ray analysis. The endproducts observed are U3O8 and UO2 in air/He and hydrogen, respe......, respectively. The following intermediate products were observed in all atmospheres: http://www.sciencedirect.com.globalproxy.cvt.dk/cache/MiamiImageURL/B6THV-44K80TV-FB-1/0?wchp=dGLzVlz-zSkWW X-ray diffraction analysis showed that these phases were amorphous....

  3. Alkali-metal ion coordination in uranyl(VI) poly-peroxo complexes in solution, inorganic analogues to crown-ethers. Part 2. Complex formation in the tetramethyl ammonium-, Li(+)-, Na(+)- and K(+)-uranyl(VI)-peroxide-carbonate systems.

    Science.gov (United States)

    Zanonato, Pier Luigi; Szabó, Zoltán; Vallet, Valerie; Di Bernardo, Plinio; Grenthe, Ingmar

    2015-10-01

    The constitution and equilibrium constants of ternary uranyl(vi) peroxide carbonate complexes [(UO2)p(O2)q(CO3)r](2(p-q-r)) have been determined at 0 °C in 0.50 M MNO3, M = Li, K, and TMA (tetramethyl ammonium), ionic media using potentiometric and spectrophotometric data; (17)O NMR data were used to determine the number of complexes present. The formation of cyclic oligomers, "[(UO2)(O2)(CO3)]n", n = 4, 5, 6, with different stoichiometries depending on the ionic medium used, suggests that Li(+), Na(+), K(+) and TMA ions act as templates for the formation of uranyl peroxide rings where the uranyl-units are linked by μ-η(2)-η(2) bridged peroxide-ions. The templating effect is due to the coordination of the M(+)-ions to the uranyl oxygen atoms, where the coordination of Li(+) results in the formation of Li[(UO2)(O2)(CO3)]4(7-), Na(+) and K(+) in the formation of Na/K[(UO2)(O2)(CO3)]5(9-) complexes, while the large tetramethyl ammonium ion promotes the formation of two oligomers, TMA[(UO2)(O2)(CO3)]5(9-) and TMA[(UO2)(O2)(CO3)]6(11-). The NMR spectra demonstrate that the coordination of Na(+) in the five- and six-membered oligomers is significantly stronger than that of TMA(+); these observations suggest that the templating effect is similar to the one observed in the synthesis of crown-ethers. The NMR experiments also demonstrate that the exchange between TMA[(UO2)(O2)(CO3)]5(9-) and TMA[(UO2)(O2)(CO3)]6(11-) is slow on the (17)O chemical shift time-scale, while the exchange between TMA[(UO2)(O2)(CO3)]6(11-) and Na[(UO2)(O2)(CO3)]6(11-) is fast. There was no indication of the presence of large clusters of the type identified by Burns and Nyman (M. Nyman and P. C. Burns, Chem. Soc. Rev., 2012, 41, 7314-7367) and possible reasons for this and the implications for the synthesis of large clusters are briefly discussed.

  4. Carbonated water (CW) process waste reuse for ammonium-uranyl-carbonate (AUC) production and its gains on the environmental, economic and social aspects

    Energy Technology Data Exchange (ETDEWEB)

    Carnaval, Joao Paulo R.; Santos, Rafael D. dos; Barbosa, Rodrigo A.; Lauer, Sergio, E-mail: joaocarnaval@inb.gov.br, E-mail: rafaelsantos@inb.gov.br, E-mail: rodrigobarbosa@inb.gov.br, E-mail: lauer@inb.gov.br [Industias Nucleares do Brasil S.A. (INB), Resende, RJ (Brazil)

    2013-07-01

    In the INB nuclear fuel cycle, the pellets production is based on UO{sub 2} powder made by AUC (Ammonium-Uranyl-Carbonate) route. AUC formation occurs by fluidising of UF{sub 6}, NH{sub 3} and CO{sub 2} in a vase containing usually pure water, and this exothermal reaction has AUC as direct product. The mass formed is filtered, washed with CW, washed again with methano solution, dried with air and conducted to the fluidized bed furnace, to be converted to UO{sub 2} powder. At this point, the dried AUC decompounds to UO{sub 3}, NH{sub 3} and C0{sub 2}, these 2 gases are absorbed at the gases washer, formin go the carbonated water (CW), whit is basically a (NH{sub 4}){sub 2}CO{sub 3} solution. The UO{sub 2+x} is reduced and stabilized to UO{sub 2} powder, which is conducted to pellets production. During the process, a considerable amount of this aqueous waste is generated and goes for effluent treatment. After that, the solution is sent for spray-dryer for power formation, and stock. This treatment demands equipment, energy and time, representing considerable costs of the company beyond the human risks involved on the drying step. The purpose of this work is to present a study of the carbonated water use as substitute of pure water in the AUC formation step. At this point, tests were made varying the CW loads for the AUC precipitation, and the control was made by the UO{sub 2} powder properties. The carbonated water used for AUC precipitation has been tested at several levels and the results has demonstrated full viability to become a definitive process step (INB, Resende site). It has been demonstrated the great resources economy caused by the waste reuse and the guarantee product quality. This represents such an environmental gain and also economic and social aspects got improved. (author)

  5. Molecular simulation of the diffusion of uranyl carbonate species in aqueous solution

    Science.gov (United States)

    Kerisit, Sebastien; Liu, Chongxuan

    2010-09-01

    Potential-based molecular dynamics simulations of aqueous uranyl carbonate species (M xUO 2(CO 3) y2+2x-2y with M = Mg, Ca, or Sr) were carried out to gain molecular-level insight into the hydration properties of these species. The simulation results were used to estimate the self-diffusion coefficients of these uranyl carbonate species, which often dominate uranyl speciation in groundwater systems. The diffusion coefficients obtained for the monoatomic alkaline-earth cations and polyatomic ions (uranyl, carbonate, and uranyl tri-carbonate) were compared with those calculated from the Stokes-Einstein (SE) equation and its variant formulation by Impey et al. (1983). Our results show that the equation of Impey et al. (1983), originally formulated for monovalent monoatomic ions, can be extended to divalent monoatomic ions, with some success in reproducing the absolute values and the overall trend determined from the molecular dynamics simulations, but not to polyatomic ions, for which the hydration shell is not spherically symmetrical. Despite the quantitative failure of both SE formulations, a plot of the diffusion coefficients of the uranyl carbonate complexes as a function of the inverse of the equivalent spherical radius showed that a general linear dependence is observed for these complexes as expected from the SE equation. The nature of the alkaline-earth cation in the uranyl carbonate complexes was not found to have a significant effect on the ion's diffusion coefficient, which suggests that the use of a single diffusion coefficient for different alkaline-earth uranyl carbonate complexes in microscopic diffusion models is appropriate. The potential model reproduced well published quantum mechanical and experimental data of UO(CO)32x-4 and of the individual constituent ions, and therefore is expected to offer reliable predictions of the structure of magnesium and strontium uranyl carbonate aqueous species, for which there is no structural data available to date

  6. Atomistic simulations of calcium uranyl(VI) carbonate adsorption on calcite and stepped-calcite surfaces.

    Science.gov (United States)

    Doudou, Slimane; Vaughan, David J; Livens, Francis R; Burton, Neil A

    2012-07-17

    Adsorption of actinyl ions onto mineral surfaces is one of the main mechanisms that control the migration of these ions in environmental systems. Here, we present computational classical molecular dynamics (MD) simulations to investigate the behavior of U(VI) in contact with different calcite surfaces. The calcium-uranyl-carbonate [Ca(2)UO(2)(CO(3))(3)] species is shown to display both inner- and outer-sphere adsorption to the flat {101̅4} and the stepped {314̅8} and {31̅2̅16} planes of calcite. Free energy calculations, using the umbrella sampling method, are employed to simulate adsorption paths of the same uranyl species on the different calcite surfaces under aqueous condition. Outer-sphere adsorption is found to dominate over inner-sphere adsorption because of the high free energy barrier of removing a uranyl-carbonate interaction and replacing it with a new uranyl-surface interaction. An important binding mode is proposed involving a single vicinal water monolayer between the surface and the sorbed complex. From the free energy profiles of the different calcite surfaces, the uranyl complex was also found to adsorb preferentially on the acute-stepped {314̅8} face of calcite, in agreement with experiment.

  7. Carbonization of solid uranyl-ascorbate gel as an indirect step of uranium carbide synthesis

    Directory of Open Access Journals (Sweden)

    Brykala Marcin

    2015-12-01

    Full Text Available The studies of the synthesis of uranium carbide from uranyl-ascorbate gels using the complex sol-gel process (CSGP have been carried out. The synthesis of uranyl-ascorbate mixture as liquid sol from uranium trioxide and ascorbic acid and solid gel by extraction of water from sol were carefully examined. Ascorbic acid was used as a complexing agent in complex sol-gel process and as a carbon source. The crucial step to obtain final uranium carbides from the aforementioned substrates is the carbonization process. The thermal behavior of ascorbic acid and uranyl-ascorbate gels in a nitrogen atmosphere in the temperature range of 25-900°C were investigated using TG-DTG. Furthermore, the products of the carbonization of uranyl-ascorbate gels in nitrogen, argon and vacuum atmosphere were identified by X-ray diffraction. TG-DTG was used also as a method for determining of carbon residues in the samples.

  8. A cryogenic fluorescence spectroscopic study of uranyl carbonate, phosphate and oxyhydroxide minerals

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Z.; Zachara, J.M.; Liu, C.; Gassman, P.L.; Felmy, A.R. [Pacific Northwest National Lab., Richland, WA (United States); Clark, S.B. [Washington State Univ., Pullman, WA (United States)

    2008-07-01

    In this work we applied time-resolved laser-induced fluorescence spectroscopy (TRLIF) at both room temperature (RT) and near liquid-helium temperature (6 K) to characterize a series of natural and synthetic minerals of uranium carbonate, phosphate and oxyhydroxides including rutherfordine, zellerite, liebigite, phosphuranylite, meta-autunite, meta-torbernite, uranyl phosphate, sodium-uranyl-phosphate, becquerelite, schoepite, meta-schoepite, dehydrated schoepite and compreignacite, and have compared the spectral characteristics among these minerals as well as our previously published data on uranyl silicates. For the carbonate minerals, the fluorescence spectra of rutherfordine showed significant difference from those of zellerite and liebigite. The fluorescence spectra of the phosphate minerals closely resemble each other despite the differences in their composition and structure. For all uranium oxyhydroxides, the fluorescence spectra are largely red-shifted as compared to those of the uranium carbonates and phosphates and their vibronic bands are broad and less resolved at RT. The enhanced spectra resolution at 6 K allows more accurate determination of the fluorescence band origin and offers a complemental method to measure the O=U=O symmetrical stretch frequency, {nu}{sub 1}, from the spacings of the vibronic bands of the fluorescence spectra. The average {nu}{sub 1} values appear to be inversely correlated with the average pK{sub a} values of the anions. (orig.)

  9. A cryogenic fluorescence spectroscopic study of uranyl carbonate, phosphate, and oxyhydroxide minerals

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Zheming; Zachara, John M.; Liu, Chongxuan; Gassman, Paul L.; Felmy, Andrew R.; Clark, Sue B.

    2008-11-03

    In this work we have applied liquid-helium temperature (LHeT) time-resolved laser-induced fluorescence spectroscopy (TRLIF) to characterize a series of natural and synthetic minerals of uranium carbonate, phosphate and oxyhydroxides including rutherfordine, zellerite, liebigite, phosphuranylite, meta-autunite, meta-torbernite, uranyl phosphate, sodium-uranyl-phosphate, bequerelite, clarkeite, curite, schoepite and compregnacite, and compared their spectral characteristics among these minerals as well as our previously published data on uranyl silicates. For the carbonate minerals, the fluorescence spectra depend on the stoichiometry of the mineral. For the phosphate minerals the fluorescence spectra closely resemble each other despite the differences in their composition and structure. For all uranium oxyhydroxides, the fluorescence spectra are largely red-shifted as compared with those of the uranium carbonates and phosphates and their vibronic bands are broadened and less resolved. The much enhanced spectra resolution at LHeT allows more accurate calculation of the O=U=O symmetrical stretch frequency, ν1, corresponding to the average spacing of the vibronic peaks of the fluorescence spectra and the spectral origin as reflected by the position of the first vibronic band. It was found that both the average ν1 and λ1 values correlate well with the average basicity of the inorganic anion.

  10. DFT studies of uranyl acetate, carbonate, and malonate, complexes in solution.

    Science.gov (United States)

    Vázquez, Jordi; Bo, Carles; Poblet, Josep Maria; de Pablo, Joan; Bruno, Jordi

    2003-09-22

    The aim of this work is to demonstrate that theoretical chemistry can be used as a complementary tool in determining geometric parameters of a number of uranyl complexes in solution, which are not observable by experimental methods. In addition, we propose plausible structures with partial geometric data from experimental results. A gradient corrected DFT methodology with relativistic effects is used employing a COSMO solvation model. The theoretical calculations show good agreement with experimental X-ray and EXAFS data for the triacetato-dioxo-uranium(VI) and tricarbonato-dioxo-uranium(VI) complexes and are used to assign possible geometries for dicalcium-tricarbonato-dioxo-uranium(VI) and malonato-dioxo-uranium(VI) complexes. The results of this exercise indicate that carbonate bonding in these complexes is mainly bidentate and that hydroxo bridging plays a critical role in the stabilization of the polynuclear uranyl complexes.

  11. Lactulose production from cheese whey using recyclable catalyst ammonium carbonate.

    Science.gov (United States)

    Seo, Yeong Hwan; Sung, Mina; Han, Jong-In

    2016-04-15

    Ammonium carbonate ((NH4)2CO3) was used as an alkaline catalyst of lactulose production from cheese whey. Maximum yield of 29.6% was obtained at reaction time of 28.44 min, (NH4)2CO3 of 0.76% at 97°C. During reaction, (NH4)2CO3 was fully decomposed to NH3 and CO2, and these gases were recovered. To boost up NH3 recovery, various methods such as heating, aeration, and pH adjustment were applied. The optimal condition for the purpose of NH3 retrieval was temperature of up to 60°C alongside aeration. Easy separation and recovery make (NH4)2CO3 a catalyst alternative to common alkaline chemicals especially for the weak alkaline reaction.

  12. Uranyl ion coordination

    Science.gov (United States)

    Evans, H.T.

    1963-01-01

    A review of the known crystal structures containing the uranyl ion shows that plane-pentagon coordination is equally as prevalent as plane-square or plane-hexagon. It is suggested that puckered-hexagon configurations of OH - or H2O about the uranyl group will tend to revert to plane-pentagon coordination. The concept of pentagonal coordination is invoked for possible explanations of the complex crystallography of the natural uranyl hydroxides and the unusual behavior of polynuclear ions in hydrolyzed uranyl solutions.

  13. Dissolution of Irradiated Commercial UO2 Fuels in Ammonium Carbonate and Hydrogen Peroxide

    Energy Technology Data Exchange (ETDEWEB)

    Soderquist, Chuck Z.; Johnsen, Amanda M.; McNamara, Bruce K.; Hanson, Brady D.; Chenault, Jeffrey W.; Carson, Katharine J.; Peper, Shane M.

    2011-01-18

    We propose and test a disposition path for irradiated nuclear fuel using ammonium carbonate and hydrogen peroxide media. We demonstrate on a 13 g scale that >98% of the irradiated fuel dissolves. Subsequent expulsion of carbonate from the dissolver solution precipitates >95% of the plutonium, americium, curium, and substantial amounts of fission products, effectively partitioning the fuel at the dissolution step. Uranium can be easily recovered from solution by any of several means, such as ion exchange, solvent extraction, or direct precipitation. Ammonium carbonate can be evaporated from solution and recovered for re-use, leaving an extremely compact volume of fission products, transactinides, and uranium. Stack emissions are predicted to be less toxic, less radioactive, chemically simpler, and simpler to treat than those from the conventional PUREX process.

  14. Modeling conversion of ammonium diuranate (ADU) into uranium dioxide (UO2) powder

    Science.gov (United States)

    Hung, Nguyen Trong; Thuan, Le Ba; Khoai, Do Van; Lee, Jin-Young; Jyothi, Rajesh Kumar

    2016-10-01

    In the paper, Brandon mathematical model that describes the relationship between the essential fabrication parameters [reduction temperature (TR), calcination temperature (TC), calcination time (tC) and reduction time (tR)] and specific surface area of ammonium diuranate (ADU)-derived UO2 powder products was established. The proposed models can be used to predict and control the specific surface area of UO2 powders prepared through ADU route. Suitable temperatures for conversion of ADU and ammonium uranyl carbonate (AUC) was examined with the proposed model through assessment of the sinterability of UO2 powders.

  15. Reactivity of Mg-Al hydrotalcites in solid and delaminated forms in ammonium carbonate solutions

    Science.gov (United States)

    Stoica, Georgiana; Santiago, Marta; Abelló, Sònia; Pérez-Ramírez, Javier

    2010-10-01

    Treatment of Mg-Al hydrotalcites (LDHs, layered double hydroxides) in aqueous (NH 4) 2CO 3 at 298 K leads to composites of dawsonite, hydrotalcite, and magnesium ammonium carbonate. The mechanism and kinetics of this transformation, ultimately determining the relative amounts of these components in the composite, depend on the treatment time (from 1 h to 9 days), the Mg/Al ratio in the hydrotalcite (2-4), and on the starting layered double hydroxide (solid or delaminated form). The materials at various stages of the treatment were characterized by inductive coupled plasma-optical emission spectroscopy, X-ray diffraction, transmission electron microscopy, infrared spectroscopy, thermogravimetry, and nitrogen adsorption at 77 K. The progressive transformation of hydrotalcite towards crystalline dawsonite and magnesium ammonium carbonate phases follows a dissolution-precipitation mechanism. A gradual decrease of the Mg/Al ratio in the resulting solids was observed in time due to magnesium leaching in the reacting medium. Dawsonite-hydrotalcite composite formation is favored at high aluminum contents in the starting hydrotalcite, while the formation of magnesium ammonium carbonate is favored at high Mg/Al ratios. The synthetic strategy comprising hydrotalcite delamination in formamide prior to aqueous (NH 4) 2CO 3 treatment is more reactive towards composite formation than starting from the bulk solid hydrotalcite.

  16. Uranyl salophenes as ionophores for phosphate-selective electrodes

    NARCIS (Netherlands)

    Wroblewski, Wojciech; Wojciechowski, Kamil; Dybko, Artur; Brzozka, Zbigniew; Egberink, Richard J.M.; Snellink-Ruel, Bianca H.M.; Reinhoudt, David N.

    2000-01-01

    Anion selectivities of poly(vinylchloride) (PVC) plasticized membranes containing uranyl salophene derivatives were presented. The influence of the membrane components (i.e. ionophore structure, dielectric constant and structure of plasticizer, the amount of incorporated ammonium salt) on its phosph

  17. Dimethyl carbonate synthesis via transesterification catalyzed by quaternary ammonium salt functionalized chitosan

    Institute of Scientific and Technical Information of China (English)

    Yuan Zhao; Liang Nian He; Yuan Yi Zhuang; Jin Quan Wang

    2008-01-01

    A quaternary ammonium salt covalently linked to chitosan was first used as a catalyst for dimethyl carbonate (DMC) synthesis by the transesterification of propylene carbonate (PC) with methanol. The effects of various reaction variables like reaction time, temperature and pressure on the catalytic performance were also investigated. 54% DMC yield and 71% PC conversion were obtained under the optimal reaction conditions. Notably, the catalyst was able to be reused with retention of high catalytic activity and selectivity. Consequently, the process presented here has great potential for industrial application due to its advantages such as stability, easy preparation from renewable biopolymer, and simple separation from products.

  18. Effect of inorganic carbon on anaerobic ammonium oxidation enriched in sequencing batch reactor

    Institute of Scientific and Technical Information of China (English)

    Liao Dexiang; Li Xiaoming; Yang Qi; Zeng Guangming; Guo Liang; Yue Xiu

    2008-01-01

    The present lab-scale research reveals the enrichment of anaerobic ammonium oxidation microorganism from methanogenic anaerobic granular sludge and the effect of inorganic carbon (sodium bicarbonate) on anaerobic ammonium oxidation. The enrichment of anammox bacteria was carried out in a 7.0-L SBR and the effect of bicarbonate on anammox was conducted in a 3.0-L SBR. Research results , especially the biomass, showed first signs of anammox activity after 54 d cultivation with synthetic wastewater, when the pH was controlled between 7.5 and 8.3, the temperature was 35℃. The anammox activity increased as the influent bicarbonate concentration increased from 1.0 to 1.5 g/L and then, was inhibited as the bicarbonate concentration approached 2.0 g/L. However, the activity could be restored by the reduction of bicarbonate concentration to 1.0 g/L, as shown by rapid conversion of ammonium, and nitrite and nitrate production with normal stoichiometry. The optimization of the bicarbonate concentration in the reactor could increase the anammox rate up to 66.4 mgN/(L·d).

  19. Enhancement of Glucose Utilization in Provision of Carbon Skeletons for Ammonium Assimilation in Wheat Roots

    OpenAIRE

    Koga, Nobuhisa; Ikeda, Motoki

    2000-01-01

    In providing carbon skeletons to be expended for amide synthesis during ammonium assimilation, glucose utilization in roots was studied. The roots of young wheat plants grown without nitrogen for 3d and grown with 4 mM NO_3^- or NH_4^+ for 1d were fed with ^C-glucose for 3h in the presence of NO_3^- or NH_4^+, and the distribution of ^C-metabolites within the plants was examined. The NH_4^+ supply changed the distribution of ^C to a greater extent than the NO_3^- supply. In roots grown with N...

  20. Porous polymers bearing functional quaternary ammonium salts as efficient solid catalysts for the fixation of CO2 into cyclic carbonates

    Science.gov (United States)

    Cai, Sheng; Zhu, Dongliang; Zou, Yan; Zhao, Jing

    2016-07-01

    A series of porous polymers bearing functional quaternary ammonium salts were solvothermally synthesized through the free radical copolymerization of divinylbenzene (DVB) and functionalized quaternary ammonium salts. The obtained polymers feature highly cross-linked matrices, large surface areas, and abundant halogen anions. These polymers were evaluated as heterogeneous catalysts for the synthesis of cyclic carbonates from epoxides and CO2 in the absence of co-catalysts and solvents. The results revealed that the synergistic effect between the functional hydroxyl groups and the halide anion Br- afforded excellent catalytic activity to cyclic carbonates. In addition, the catalyst can be easily recovered and reused for at least five cycles without significant loss in activity.

  1. Dipole Alignment at the Carbon Nanotube and Methyl Ammonium Lead Iodide Perovskite Interface

    Energy Technology Data Exchange (ETDEWEB)

    Przepioski, Joshua [SLAC National Accelerator Lab., Menlo Park, CA (United States)

    2015-08-28

    This work correlates resonant peaks from first principles calculation on ammonia (NH3) Nitrogen 1s x-ray absorption spectroscopy (XAS) within the methyl ammonium lead iodide perovskite (CH3NH3PbI3), and proposes a curve to determine the alignment of the methyl ammonium dipole if there exists angular dependence. The Nitrogen 1s XAS was performed at varying incident angles on the perovskite with and without a carbon nanotube (CNT) interface produced from an ultrasonic spray deposition. We investigated the peak contribution from PbI2 and the poly(9,9-dioctylfluorene- 2,7-diyl) with bipyridine (PFO-BPy) wrapped around the CNT, and used normalization techniques to better identify the dipole alignment. There was angular dependence on samples containing the CNT interface suggesting an existing dipole alignment, but there was no angular dependence on the perovskite samples alone; however, more normalization techniques and experimental work must be performed in order to ensure its validity and to better describe its alignment, and possible controlling factors.

  2. Dipole Alignment at the Carbon Nanotube and Methyl Ammonium Lead Trihalide Perovskite Interface - Oral Presentation

    Energy Technology Data Exchange (ETDEWEB)

    Przepioski, Joshua [SLAC National Accelerator Lab., Menlo Park, CA (United States)

    2015-08-25

    This work correlates resonant peaks from first principles calculation on ammonia (NH3) Nitrogen 1s x-ray absorption spectroscopy (XAS) within the methyl ammonium lead iodide perovskite (CH3NH3PbI3), and proposes a curve to determine the alignment of the methyl ammonium dipole if there exists angular dependence. The Nitrogen 1s XAS was performed at varying incident angles on the perovskite with and without a carbon nanotube (CNT) interface produced from an ultrasonic spray deposition. We investigated the peak contribution from PbI2 and the poly(9,9-dioctylfluorene-2,7-diyl) with bipyridine (PFO-BPy) wrapped around the CNT, and used normalization techniques to better identify the dipole alignment. There was angular dependence on samples containing the CNT interface suggesting an existing dipole alignment, but there was no angular dependence on the perovskite samples alone; however, more normalization techniques and experimental work must be performed in order to ensure its validity and to better describe its alignment, and possible controlling factors.

  3. Reuse of ammonium fluoride generated in the uranium hexafluoride conversion; Reutilizacao do fluoreto de amonio gerado na reconversao do hexafluoreto de uranio

    Energy Technology Data Exchange (ETDEWEB)

    Silva Neto, J.B.; Carvalho, E.F. Urano de; Durazzo, M., E-mail: jbsneto@ipen.b [Instituto de Pesquisas Energeticas e Nucleares (IPEN/CNEN-SP), Sao Paulo, SP (Brazil); Riella, H.G [Universidade Federal de Santa Catarina (UFSC), Florianopolis, SC (Brazil)

    2010-07-01

    The Nuclear Fuel Centre of IPEN / CNEN - SP develops and manufactures dispersion fuel with high uranium concentration to meet the demand of the IEA-R1 reactor and future research reactors planned to be constructed in Brazil. The fuel uses uranium silicide (U{sub 3}Si{sub 2}) dispersed in aluminum. For producing the fuel, the processes for uranium hexafluoride (UF{sub 6}) conversion consist in obtaining U{sub 3}Si{sub 2} and / or U{sub 3}O{sub 8} through the preparation of intermediate compounds, among them ammonium uranyl carbonate - AUC, ammonium diuranate - DUA and uranium tetrafluoride - UF{sub 4}. This work describes a procedure for preparing uranium tetrafluoride by a dry route using as raw material the filtrate generated when producing routinely ammonium uranyl carbonate. The filtrate consists primarily of a solution containing high concentrations of ammonium (NH{sub 4}{sup +}), fluoride (F{sup -}), carbonate (CO{sub 3}{sup --}) and low concentrations of uranium. The procedure is basically the recovery of NH{sub 4}F and uranium, as UF{sub 4}, through the crystallization of ammonium bifluoride (NH{sub 4}HF{sub 2}) and, in a later step, the addition of UO{sub 2}, occurring fluoridation and decomposition. The UF{sub 4} obtained is further diluted in the UF{sub 4} produced routinely at IPEN / CNEN-SP by a wet route process. (author)

  4. Continuing assessment of the 5 day sodium carbonate-ammonium nitrate extraction assay as an indicator test for silicon fertilizers

    Science.gov (United States)

    The five day sodium carbonate-ammonium nitrate extraction assay has been proposed by the AAFPCO as a standard test to identify fertilizers that provide plant-available Si. A single-lab validation test was previously performed; however, the analysis lacked any correlation to a grow-out study. To do...

  5. Effect of carbon dioxide and ammonium removal on pH changes in polishing ponds.

    Science.gov (United States)

    Cavalcanti, P F F; van Haandel, A; Lettinga, G

    2002-01-01

    If nutrient removal is to be obtained in ponds treating sewage, the pH must be raised so that ammonia can desorb and phosphates can precipitate. In this paper it is shown that the pH increase in ponds can be predicted quantitatively from simple stoichiometry, taking into consideration physical and biological carbon dioxide removal, ammonia stripping and calcium carbonate precipitation. Biological CO2 removal by photosynthesis is identified as the main process to effect pH increase in ponds. The rate of pH increase and consequently the required retention time depend on the net rate of CO2 consumption, the extent of ammonium stripping, the characteristics of the influent (alkalinity and pH) as well as factors concerning the environment (temperature) and dimensions (depth) of the pond. A high pH (range 9 to 10) can be obtained in about 5 days if digested sewage is used (low organic material concentration), climate conditions are favourable and the pond is shallow (< 0.5 m deep).

  6. Surface complexation model of uranyl sorption on Georgia kaolinite

    Science.gov (United States)

    Payne, T.E.; Davis, J.A.; Lumpkin, G.R.; Chisari, R.; Waite, T.D.

    2004-01-01

    The adsorption of uranyl on standard Georgia kaolinites (KGa-1 and KGa-1B) was studied as a function of pH (3-10), total U (1 and 10 ??mol/l), and mass loading of clay (4 and 40 g/l). The uptake of uranyl in air-equilibrated systems increased with pH and reached a maximum in the near-neutral pH range. At higher pH values, the sorption decreased due to the presence of aqueous uranyl carbonate complexes. One kaolinite sample was examined after the uranyl uptake experiments by transmission electron microscopy (TEM), using energy dispersive X-ray spectroscopy (EDS) to determine the U content. It was found that uranium was preferentially adsorbed by Ti-rich impurity phases (predominantly anatase), which are present in the kaolinite samples. Uranyl sorption on the Georgia kaolinites was simulated with U sorption reactions on both titanol and aluminol sites, using a simple non-electrostatic surface complexation model (SCM). The relative amounts of U-binding >TiOH and >AlOH sites were estimated from the TEM/EDS results. A ternary uranyl carbonate complex on the titanol site improved the fit to the experimental data in the higher pH range. The final model contained only three optimised log K values, and was able to simulate adsorption data across a wide range of experimental conditions. The >TiOH (anatase) sites appear to play an important role in retaining U at low uranyl concentrations. As kaolinite often contains trace TiO2, its presence may need to be taken into account when modelling the results of sorption experiments with radionuclides or trace metals on kaolinite. ?? 2004 Elsevier B.V. All rights reserved.

  7. Uranyl Oxalate Solubility

    Energy Technology Data Exchange (ETDEWEB)

    Leturcq, G.; Costenoble, S.; Grandjean, S. [CEA Marcoule DEN/DRCP/SCPS/LCA - BP17171 - 30207 Bagnols sur Ceze cedex (France)

    2008-07-01

    The solubility of uranyl oxalate was determined at ambient temperature by precipitation in oxalic-nitric solutions, using an initial uranyl concentration of 0.1 mol/L. Oxalic concentration varied from 0.075 to 0.3 mol/L while nitric concentration ranged between 0.75 and 3 mol/L. Dissolution tests, using complementary oxalic-nitric media, were carried out for 550 hours in order to study the kinetic to reach thermodynamic equilibrium. Similar solubility values were reached by dissolution and precipitation. Using the results, it was possible to draw the solubility surface versus oxalic and nitric concentrations and to determine both the apparent solubility constant of UO{sub 2}C{sub 2}O{sub 4}, 3H{sub 2}O (Ks) and the apparent formation constant of the first uranyl-oxalate complex UO{sub 2}C{sub 2}O{sub 4} (log {beta}1), for ionic strengths varying between 1 and 3 mol/L. Ks and log {beta}1 values were found to vary from 1.9 10{sup -8} to 9.2 10{sup -9} and from 5.95 to 6.06, respectively, when ionic strength varied from 1 to 3 mol/L. A second model may fit our data obtained at an ionic strength of 3 mol/L suggesting as reported by Moskvin et al. (1959) that no complexes are formed for [H{sup +}] at 3 M. The Ks value would then be 1.3 10{sup -8}. (authors)

  8. Revealing Brown Carbon Chromophores Produced in Reactions of Methylglyoxal with Ammonium Sulfate

    Energy Technology Data Exchange (ETDEWEB)

    Lin, Peng; Laskin, Julia; Nizkorodov, Sergey A.; Laskin, Alexander

    2015-12-15

    Atmospheric brown carbon (BrC) is an important contributor to light absorption and climate forcing by aerosols. Reactions between small water-soluble carbonyls and ammonia or amines have been identified as one of the potential pathways of BrC formation. However, detailed chemical characterization of BrC chromophores has been challenging and their formation mechanisms are still poorly understood. Understanding BrC formation is impeded by the lack of suitable methods which can unravel the variability and complexity of BrC mixtures. This study applies high performance liquid chromatography (HPLC) coupled to photodiode array (PDA) detector and high resolution mass spectrometry (HRMS) to investigate optical properties and chemical composition of individual BrC components produced through reactions of methylglyoxal (MG) and ammonium sulfate (AS), both of which are abundant in the atmospheric environment. A direct relationship between optical properties and chemical composition of 30 major BrC chromophores was established. Nearly all of these chromophores are nitrogen-containing compounds that account for >70% of the overall light absorption by the MG+AS system in the 300-500 nm range. These results suggest that reduced-nitrogen organic compounds formed in reactions between atmospheric carbonyls and ammonia/amines are important BrC chromophores. It is also demonstrated that improved separation of BrC chromophores by HPLC will significantly advance understanding of BrC chemistry.

  9. Dissolution of Uranium(IV) Oxide in Solutions of Ammonium Carbonate and Hydrogen Peroxide

    Energy Technology Data Exchange (ETDEWEB)

    Smith, Steven C.; Peper, Shane M.; Douglas, Matthew; Ziegelgruber, Kate L.; Finn, Erin C.

    2009-09-12

    Understanding the dissolution characteristics of uranium oxides is of fundamental scientific interest. Bench scale experiments were conducted to determine the optimal dissolution parameters of uranium(IV) oxide (UO2) powder in solutions of ammonium carbonate [(NH4)2CO3] and hydrogen peroxide (H2O2). Experimental parameters included variable peroxide and carbonate concentrations, and temperature. Results indicate the dissolution rate of UO2 in 1 M (NH4)2CO3 increases linearly with peroxide concentration ranging from 0.05 – 2 M (1:1 to 40:1 mol ratio H2O2:U), with no apparent maximum rate reached under the limited conditions used in our study. Temperature ranging studies show the dissolution rate of UO2 in 1 M (NH4)2CO3 and 0.1 M H2O2 (2:1 mol ratio H2O2:U) increases linearly from 15 °C to 60 °C, again with no apparent maximum rate reached. Dissolution of UO2 in solutions with constant [H2O2] and [(NH4)2CO3] ranging from 0.5 to 2 M showed no difference in rate; however dissolution was significantly reduced in 0.05 M (NH4)2CO3 solution. The results of this study demonstrate the influence of [H2O2], [(NH4)2CO3], and temperature on the dissolution of UO2 in peroxide-containing (NH4)2CO3 solutions. Future studies are planned to elucidate the solution and solid state complexes in these systems.

  10. Effect of Electrochemical Treatment in Aqueous Ammonium Bicarbonate on Surface Properties of PAN-based Carbon Fibers

    Institute of Scientific and Technical Information of China (English)

    曹海琳; 黄玉东; 张志谦; 孙举涛

    2004-01-01

    The surface properties of PAN-based carbon fibers electrochemically treated in aqueous ammonium bicarbonate before and after treatment were characterized by X-ray photoelectron spectroscopy (XPS), atomic force microscopy (AFM) and Dynamic Contact Angle Analysis (DCAA). The results of characterization indicated that the oxygen and nitrogen contents in carbon fiber surface were significantly increased by electrochemical treatment, and amide groups was introduced onto it, which was related with the electrolyte. The AFM photographs illustrated that the roughness of the fiber surface was also increased. The wettibality of the fibers was improved after treatment because the surface energy especially the polar part of it was increased.

  11. Isotherm And Kinetic Studies On The Electrosorption Of Uranyl Tricarbonate Complex [UO{sub 2}(CO{sub 3}){sub 3}]{sup 4-} From Aqueous Solutions By Activated Carbon Electrodes

    Energy Technology Data Exchange (ETDEWEB)

    Ismail, Aznan Fazli; Yim, Man Sung [Korea Advanced Institute of Science and Technology, Daejeon (Korea, Republic of)

    2015-05-15

    Many types of adsorbent materials have been developed over the past 50 years, and the most recognizable is amidoxime based materials which is known to have high affinity in in chelating uranyl ions from seawater. However, the fabrication cost of amidoxime based materials was high which lead to high uranium extraction cost. In recent studies, use of porous carbon materials combined with the electrosorption technique was shown to have high selectivity for uranium separation from seawater. It is clear that the electrosorption capacity increase with the increasing of electrolyte concentration. The investigated activated carbon electrode still not reach the maximum adsorption capacity in the test condition. The morphology analysis confirmed that the fabricated activated carbon electrode has a porous structure, where BET analysis has revealed that the size of the pores can be categorized in mesopores region which is the optimum condition for electrosorption purposes. Other than that, the FT-IR analysis has enough evident that the molecular interaction of the activated carbon electrode involves the intermolecular interaction (physical crosslink/bonding) and stable for electrosorption application.

  12. Separation of Tetramethyl Ammonium Hydroxide in Waste Water with Ion Exchange Using Activated Carbon Prepared by Bamboo

    Science.gov (United States)

    Yamaguchi, Ayako; Nishihama, Syouhei; Yoshizuka, Kazuharu

    Activated carbon is prepared by bamboo for the selective recovery of tetramethyl ammonium hydroxide (TMAH), contained in waste water from semiconductive industry, at the end of pipe of the plant. The adsorption ability of the activated carbon from bamboo (BAC) is comparable to the commercial activated carbons. The adsorption of TMAH with BAC in batchwise system increases with increase in pH value of the aqueous solution, and the effective adsorption and elution yield is also obtained in column system. Quantitative adsorption-elution processing can be achieved with the present BAC, and thus indicating the BAC is effective material as the adsorbent of TMAH at the end of pipe of the plant.

  13. Concentration and temperature controlled oxidation and cutting of single-walled carbon nanotubes by ammonium persulfate

    Institute of Scientific and Technical Information of China (English)

    AHMAD; Mirza; Nadeem

    2010-01-01

    SWNTs were oxidized by a simple wet chemical method involving treatment in aqueous ammonium persulfate(APS) solution at a certain temperature.Fourier transform infrared spectroscopy(FTIR) and X-ray photoelectron spectroscopy(XPS) demonstrated that a large amount of oxygen containing groups such as hydroxyl groups and carbonyl groups was attached to the sidewall of SWNTs.The oxidized SWNTs showed good solubility in polar solvents including water and DMF.Atomic force microscopic images showed that SWNTs could be cut into short pipes by the highly concentrated APS solution at 80℃.With the decrease of reaction temperature or APS concentration,the oxidized SWNTs remained uncut.

  14. Effect of ammonium-salt solutions on the surface properties of carbon fibers in electrochemical anodic oxidation

    Energy Technology Data Exchange (ETDEWEB)

    Qian Xin, E-mail: qx3023@nimte.ac.cn [National Engineering Laboratory of Carbon Fiber Preparation Technology, Ningbo Institute of Material Technology and Engineering, Chinese Academy of Sciences, Ningbo 315201 (China); Wang Xuefei; Ouyang Qin; Chen Yousi; Yan Qing [National Engineering Laboratory of Carbon Fiber Preparation Technology, Ningbo Institute of Material Technology and Engineering, Chinese Academy of Sciences, Ningbo 315201 (China)

    2012-10-15

    Highlights: Black-Right-Pointing-Pointer Longitudinal grooves on the fiber surface became more well-defined and much deeper after surface treatment. Black-Right-Pointing-Pointer The concentration of oxygen and nitrogen on the fiber surface increased after surface treatment. Black-Right-Pointing-Pointer The intensity of oxidative reaction varied with the change of ammonium-salt solutions. Black-Right-Pointing-Pointer The higher the concentration of OH{sup -} ions in the electrolytes, the violent the oxidative reaction happened. - Abstract: The surfaces of polyacrylonitrile-based carbon fibers were treated by an electrochemical anodic method. Three different kinds of ammonium-salt solutions namely NH{sub 4}HCO{sub 3}, (NH{sub 4}){sub 2}CO{sub 3} and (NH{sub 4}){sub 3}PO{sub 4} were respectively chosen as the electrolytes. The effect of these electrolytes on the surface structure was studied by scanning electron microscopy (SEM), atomic force microscopy (AFM), and X-ray photoelectron spectroscopy (XPS). The results showed that longitudinal grooves on the fiber surface became more well-defined and much deeper after surface treatment, and the root mean square roughness (RMS) of carbon fiber surface increased from 4.6 nm for untreated fibers to 13.5 nm for treated fibers in (NH{sub 4}){sub 3}PO{sub 4} electrolytes. The concentration of oxygen and nitrogen atomic on the fiber surface increased after surface treatment. The tensile strength of oxidized fibers had an obvious decrease, whereas the interlaminar shear strength (ILSS) value of corresponding carbon fiber reinforced polymers (CFRPs) increased in a large extent. The intensity of oxidative reaction varied with the change of ammonium-salt solutions and electrochemical oxidation in (NH{sub 4}){sub 3}PO{sub 4} electrolyte was of the most violence. The corresponding mechanism was also discussed and the result showed that the higher the concentration of OH{sup -} ions in the electrolytes, the violent the oxidative

  15. Octa-ammonium POSS-conjugated single-walled carbon nanotubes as vehicles for targeted delivery of paclitaxel

    Directory of Open Access Journals (Sweden)

    Naghmeh Naderi

    2015-09-01

    Full Text Available Background: Carbon nanotubes (CNTs have unique physical and chemical properties. Furthermore, novel properties can be developed by attachment or encapsulation of functional groups. These unique properties facilitate the use of CNTs in drug delivery. We developed a new nanomedicine consisting of a nanocarrier, cell-targeting molecule, and chemotherapeutic drug and assessed its efficacy in vitro. Methods: The efficacy of a single-walled carbon nanotubes (SWCNTs-based nanoconjugate system is assessed in the targeted delivery of paclitaxel (PTX to cancer cells. SWCNTs were oxidized and reacted with octa-ammonium polyhedral oligomeric silsesquioxanes (octa-ammonium POSS to render them biocompatible and water dispersable. The functionalized SWCNTs were loaded with PTX, a chemotherapeutic agent toxic to cancer cells, and Tn218 antibodies for cancer cell targeting. The nanohybrid composites were characterized with transmission electron microscopy (TEM, Fourier transform infrared (FTIR, and ultraviolet–visible–near-infrared (UV–Vis–NIR. Additionally, their cytotoxic effects on Colon cancer cell (HT-29 and Breast cancer cell (MCF-7 lines were assessed in vitro. Results: TEM, FTIR, and UV–Vis–NIR studies confirmed side-wall functionalization of SWCNT with COOH-groups, PTX, POSS, and antibodies. Increased cell death was observed with PTX–POSS–SWCNT, PTX–POSS–Ab–SWCNT, and free PTX compared to functionalized-SWCNT (f-SWCNT, POSS–SWCNT, and cell-only controls at 48 and 72 h time intervals in both cell lines. At all time intervals, there was no significant cell death in the POSS–SWCNT samples compared to cell-only controls. Conclusion: The PTX-based nanocomposites were shown to be as cytotoxic as free PTX. This important finding indicates successful release of PTX from the nanocomposites and further reiterates the potential of SWCNTs to deliver drugs directly to targeted cells and tissues.

  16. Coordinated regulation of ammonium assimilation and carbon catabolism by glyoxylate in Saccharomyces cerevisiae.

    Science.gov (United States)

    González, A; Rodríguez, L; Folch, J; Soberón, M; Olivera, H

    1987-09-01

    The activities of citrate synthase (EC 4.1.3.7) and NADP+-dependent glutamate dehydrogenase (GDH) (EC 1.4.1.4) of Saccharomyces cerevisiae were inhibited in vitro by glyoxylate. In the presence of glyoxylate, pyruvate and glyoxylate pools increased, suggesting that glyoxylate was efficiently transported and catabolized. Pyruvate accumulation also indicates that citrate synthase was inhibited. A decrease in the glutamate pool was also observed under these conditions. This can be attributed to an increased transamination rate and to the inhibitory effect of glyoxylate on NADP+-dependent GDH. Furthermore, the increase in the ammonium pool in the presence of glyoxylate suggests that NADP+-dependent GDH was being inhibited in vivo, since the activity of glutamine synthetase did not decrease under these conditions. We propose that the inhibition of both citrate synthase and NADP+-dependent GDH could form part of a mechanism that regulates the internal 2-oxoglutarate concentration.

  17. 磷石膏-碳铵-氨水球磨制备硫酸铵和碳酸钙%Ammonium Sulfate and Calcium Carbonate Prepared by Ball-milling from Phosphogypsum-Ammonium Bicarbonate-Ammonia Water

    Institute of Scientific and Technical Information of China (English)

    李娜; 邓跃全; 董发勤; 罗绍东; 李珊珊; 彭宝瑶

    2013-01-01

    Ammonium sulfate and calcium carbonate were prepared using phosphogypsum, ammonium bicarbonate and ammonia water as raw materials by ball-milling technique. The optimum conditions were explored through orthogonal test, the major elements and phase composition of two kinds of products were analyzed by XRF and XRD, and the grain size distribution and poisonous elements of calcium carbonate were determined using laser particle size analyzer and ICP. The analysis results showed that the optimum technological conditions were as follows: the liquid-solid ratio was 0.5, the response time was 45 min, the ball-material ratio was 3:1, rotational speed was 600 r/min, and the average conversion reaction was up to 97.95%; the product quality of ammonium sulfate reached the standard of byproduct ammonium sulfate, poisonous and harmful elements contents of calcium carbonate were far lower than quality criteria of soil environment allows. Preparation of ammonium sulfate and calcium carbonate from phosphogypsum by ball-milling achieved the purpose of effectively using phosphogypsum.%  以磷石膏、碳酸氢铵和氨水为原料,采用球磨工艺制备硫酸铵和碳酸钙.通过正交试验设计,探索磷石膏球磨制备硫酸铵和碳酸钙的最佳工艺条件,采用 XRF 和 XRD 分析了2种产物的化学组成及物相组成,采用激光粒度仪和 ICP 分别测定了碳酸钙的粒度分布及有毒有害元素含量.结果表明,球磨制备硫酸铵和碳酸钙适宜的工艺条件为:液固比0.5,反应时间45 min,球料比3∶1,转速600 r/min,反应的平均转化率达97.95%;硫酸铵产品质量达到了副产硫酸铵标准,碳酸钙中有毒有害元素的含量远低于土壤环境质量标准要求.磷石膏球磨制备硫酸铵和碳酸钙,实现了磷石膏的高效利用.

  18. Electronic Structures of Uranyl(VI) Carbonate Complexes in the Aqueous Phase%水溶液中碳酸铀酰化合物的电子结构

    Institute of Scientific and Technical Information of China (English)

    辜家芳; 陆春海; 陈文凯; 陈勇; 许可; 黄昕; 章永凡

    2012-01-01

    A systematic study of series of non-hydrated and hydrated Cnlm uranyl carbonate complexes (n is number of carbonate ligands, and m is number of water molecules) in the aqueous phase was carried out using relativistic density functional theory. The conductor-like screening model was used to calculate solvent effects. The zeroth-order regular approximation was used to account for scalar relativistic effects and spin-orbit coupling relativistic effects. Time-dependent density functional theory with the inclusion of spin-orbit coupling relativistic effects was used to calculate electronic transitions using the statistically averaged orbital potentials. The results indicate that carbonate ligands play an important role in the geometric and electronic transition properties of the complex. The stability of the C3/0 carbonate complex in the aqueous phase may be attributed to the involvement of 5f components in the highest occupied bonding orbital. The addition of carbonate ligands caused a blue shift in the maximum wavelength and high intensity absorptions in the near visible region.%应用相对论密度泛函理论系统研究了水溶液中非水合化和水合化碳酸铀酰化合物Cnlm(其中仃和m分别为结构中碳酸配体和水配体的个数)的结构.溶剂效应采用类导体屏蔽模型(COSMO),并采用零级规整近似(ZORA)方法考虑标量相对论效应和旋-轨耦合相对论效应,电子跃迁采用包含旋-轨耦合相对论效应的含时密度泛函理论并在相关交换势中采用轨道势能统计平均(SAOP)做近似计算,结果表明碳酸配体对配合物结构和电子跃迁有很大的影响.C3/0配合物的稳定性可归于5f轨道参与了高占据轨道的成键作用.增加碳酸盐配体导致最大波长的蓝移,并在近町见光区域出现高强度的吸收.

  19. Ammonium hydroxide modulated synthesis of high-quality fluorescent carbon dots for white LEDs with excellent color rendering properties

    Science.gov (United States)

    Wang, Shengda; Zhu, Zhifeng; Chang, Yajing; Wang, Hui; Yuan, Nan; Li, Guopeng; Yu, Dabin; Jiang, Yang

    2016-07-01

    A novel type of aqueous fluorescent carbon dot (CD) was synthesized using citric acid as the only carbon source via an ammonium hydroxide modulated method, providing a blue color gamut. The amino group is considered to be the key factor in the high fluorescence of CDs and a model is established to investigate the mechanism of fluorescence. In addition, white light-emitting diodes (WLEDs) are fabricated by utilizing the prepared CDs and rare earth luminescent materials (SrSi2O2N2:Eu and Sr2Si5N8:Eu) as color conversion layers and UV-LED chips as the excitation light source. The WLEDs produce bright white light with attractive color rendering properties including a color rendering index of up to 95.1, a CIE coordinate of (0.33, 0.37), and a T c of 5447 K under a 100 mA driven current, indicating that the CDs are promising in the field of optoelectronic devices.

  20. Optical apparatus and method for sensing uranyl

    Science.gov (United States)

    Baylor, L.C.; Buchanan, B.R.

    1994-01-01

    An optical sensing device for uranyl and other substances, a method for making an optical sensing device and a method for chemically binding uranyl and other indicators to glass, quartz, cellulose and similar substrates. The indicator, such as arsenazo III, is immobilized on the substrate using a chemical binding process. The immobilized arsenazo III causes uranyl from a fluid sample to bind irreversibly to the substrate at its active sites, thus causing absorption of a portion of light transmitted through the substrate. Determination of the amount of light absorbed, using conventional means, yields the concentration of uranyl present in the sample fluid. The binding of uranyl on the substrate can be reversed by subsequent exposure of the substrate to a solution of 2,6-pyridinedicarboxylic acid. The chemical binding process is suitable for similarly binding other indicators, such as bromocresol green.

  1. Effect of cetyl trimethyl ammonium bromide concentration on structure, morphology and carbon dioxide adsorption capacity of calcium hydroxide based sorbents

    Energy Technology Data Exchange (ETDEWEB)

    Hlaing, Nwe Ni, E-mail: nwenihlaing76@gmail.com [School of Materials and Mineral Resources Engineering, Engineering Campus, Universiti Sains Malaysia, 14300 Nibong Tebal, Penang (Malaysia); Department of International Development Engineering, Tokyo Institute of Technology, 2-12-1 Ookayama, Meguro-ku, Tokyo (Japan); Department of Physics, University of Yangon, 11041 Kamayut, Yangon (Myanmar); Vignesh, K., E-mail: vignesh134@gmail.com [School of Materials and Mineral Resources Engineering, Engineering Campus, Universiti Sains Malaysia, 14300 Nibong Tebal, Penang (Malaysia); Anano Sphere Sdn Bhd, Lorong Industri 11, Kawasan Industri Bukit Panchor, 14300 Nibong Tebal, Penang (Malaysia); Sreekantan, Srimala, E-mail: srimala@usm.my [School of Materials and Mineral Resources Engineering, Engineering Campus, Universiti Sains Malaysia, 14300 Nibong Tebal, Penang (Malaysia); Pung, Swee-Yong [School of Materials and Mineral Resources Engineering, Engineering Campus, Universiti Sains Malaysia, 14300 Nibong Tebal, Penang (Malaysia); Hinode, Hirofumi; Kurniawan, Winarto [Department of International Development Engineering, Tokyo Institute of Technology, 2-12-1 Ookayama, Meguro-ku, Tokyo (Japan); Othman, Radzali [Faculty of Manufacturing Engineering, Universiti Teknikal Malaysia Melaka, Hang Tuah Jaya, 76100 Durian Tunggal, Malacca (Malaysia); Thant, Aye Aye [Department of Physics, University of Yangon, 11041 Kamayut, Yangon (Myanmar); Mohamed, Abdul Rahman [Low Carbon Economy (LCE) Research Group, School of Chemical Engineering, Engineering Campus, Universiti Sains Malaysia, 14300 Nibong Tebal, Penang (Malaysia); Salim, Chris [Department of Environmental Engineering, Surya University, Tangerang 15810, Banten (Indonesia)

    2016-02-15

    Graphical abstract: Carbonation conversions of (a) CC, (b) CH-2, (c) CH-4, (d) CH-6, (e) CH-8 precursor adsorbents for 10 cycles. - Highlights: • Ca(OH){sub 2} precursor was synthesized using precipitation method. • The effect of CTAB concentration on the synthesis of Ca(OH){sub 2} was studied. • The sorbent synthesized using 0.8 M of CTAB showed good CO{sub 2} adsorption capacity. • The cyclic stability of Ca(OH){sub 2} was increased with increase of CTAB concentration. - Abstract: Calcium hydroxide (Ca(OH){sub 2}) has been proposed as an important material for industrial, architectural, and environmental applications. In this study, calcium acetate was used as a precursor and cetyl trimethyl ammonium bromide (CTAB) was used as a surfactant to synthesize Ca(OH){sub 2} based adsorbents for carbon dioxide (CO{sub 2}) capture. The effect of CTAB concentration (0.2–0.8 M) on the structure, morphology and CO{sub 2} adsorption performance of Ca(OH){sub 2} was studied in detail. The synthesized samples were characterized by X-ray diffraction (XRD), Fourier transform infrared (FTIR) spectroscopy, field emission scanning electron microscopy (FESEM), BET surfaced area and thermogravimetry-differential thermal analysis (TG–DTA) techniques. The phase purity, crystallite size, Brunauer–Emmett–Teller (BET) surface area and CO{sub 2} adsorption performance of Ca(OH){sub 2} precursor adsorbents were significantly increased when the concentration of CTAB was increased. XRD results showed that pure Ca(OH){sub 2} phase was obtained at the CTAB concentration of 0.8 M. TGA results exhibited that 0.8 M of CTAB-assisted Ca(OH){sub 2} precursor adsorbent possessed a residual carbonation conversion of ∼56% after 10 cycles.

  2. Ammonium carbonate is more attractive than apple and hawthorn fruit volatile lures to Rhagoletis pomonella (Diptera: Tephritidae) in Washington State.

    Science.gov (United States)

    Yee, Wee L; Nash, Meralee J; Goughnour, Robert B; Cha, Dong H; Linn, Charles E; Feder, Jeffrey L

    2014-08-01

    The apple maggot fly, Rhagoletis pomonella (Walsh), is an introduced, quarantine pest of apple (Malus domestica Borkhausen) in the Pacific Northwest of the United States. In the eastern United States where the fly is native, fruit volatiles have been reported to be more attractive than ammonia compounds to R. pomonella. However, the opposite may be true in the western United States. Here, we determined whether newly identified western apple and western hawthorn fruit volatiles are more attractive than ammonium carbonate (AC) to R. pomonella in apple, black hawthorn, and ornamental hawthorn trees in western Washington State. In all three host trees, sticky red sphere or yellow panel traps baited with AC generally caught more flies than traps baited with lures containing the four newly developed fruit blends (modified eastern apple, western apple, western ornamental hawthorn, and western black hawthorn) or two older blends (eastern apple and eastern downy hawthorn). Fruit volatiles also displayed more variation among trapping studies conducted at different sites, in different host trees, and across years than AC. The results imply that traps baited with AC represent the best approach to monitoring R. pomonella in Washington State.

  3. Continuing Assessment of the 5-Day Sodium Carbonate-Ammonium Nitrate Extraction Assay as an Indicator Test for Silicon Fertilizers.

    Science.gov (United States)

    Zellner, Wendy; Friedrich, Russell L; Kim, Sujin; Sturtz, Douglas; Frantz, Jonathan; Altland, James; Krause, Charles

    2015-01-01

    The 5-day sodium carbonate-ammonium nitrate extraction assay (5-day method) has been recognized by the American Association of Plant Food Control Officials as a validated test method to identify fertilizers or beneficial substances that provide plant-available silicon (Si). The test method used the molybdenum blue colorimetric assay to quantify percentage Si; however, laboratories may use inductively coupled plasma optical emission spectroscopy (ICP-OES) for elemental analysis. To examine the use of either colorimetric or ICP-OES methods for Si determination, the 5-day method was performed on the following Si-containing compounds; wollastonite, sand, biochar, and a basic oven furnace (BOF) slag. Grow-out studies using Zinnia elegans were also performed using varying rates of the wollastonite, biochar, and BOF slag. Our results show using the 5-day method, wollastonite had the highest extracted amounts of silicic acid (H4SiO4) at 4% followed by biochar (2%), BOF slag (1%), and sand (0%). Extraction values calculated using either the molybdenum blue colorimetric assay or ICP-OES for detection of the H4SiO4 had a significant correlation, supporting the application of either detection method for this type of analysis. However, when extracted values were compared to amounts of Si taken up by the plants, the 5-day method overestimated both wollastonite and biochar. While this method is a valid indicator test for determining a soluble Si source, other plant species and methods should be perused to potentially provide more quantitative analyses for plant-available Si content of all materials.

  4. Uranyl Sequestration: Synthesis and Structural Characterization of Uranyl Complexes with a Tetradentate Methylterephthalamide Ligand

    Energy Technology Data Exchange (ETDEWEB)

    Ni, Chengbao; Shuh, David; Raymond, Kenneth

    2011-03-07

    Uranyl complexes of a bis(methylterephthalamide) ligand (LH{sub 4}) have been synthesized and characterized by X-ray crystallography. The structure is an unexpected [Me{sub 4}N]{sub 8}[L(UO{sub 2})]{sub 4} tetramer, formed via coordination of the two MeTAM units of L to two uranyl moieties. Addition of KOH to the tetramer gave the corresponding monomeric uranyl methoxide species [Me{sub 4}N]K{sub 2}[LUO{sub 2}(OMe)].

  5. Study on the Synthesis of Nano Ammonium Aluminum Carbonate Hydroxide (AACH)%纳米碳酸铝铵前驱体制备的研究

    Institute of Scientific and Technical Information of China (English)

    王伟礼; 毕见强; 邢政

    2008-01-01

    以硫酸铝铵(NH4Al(SO4)2)和碳酸氢铵(NH4HCO3)为主要原料,采用沉淀法制备纳米碳酸铝铵(AACH)前驱体,并利用X射线衍射(XRD),透射电镜(TEM)对前驱体的物相和形貌进行表征.研究表明,滴定速度和陈化时间对前驱体的形貌略有影响,而滴定方式和pH值对其影响较大.将硫酸铝铵溶液滴入碳酸氢铵溶液中,调节体系的pH值9-10,并将其陈化12小时,可以得到较好的前驱体.%Ammonium aluminum carbonate hydroxide (AACH) nanopowder was prepared via a precipitation reaction between ammonium aluminum sulphate (NH4 Al(SO4)2) and ammonium hydrogen carbonate (NH4 HCO3) in different conditions.The precursors were characterized by X-ray diffraction (XRD),transmission electron microscopy (TEM).The results show that titration rate and aging time affected the morphology of precursors a bit,and titration mode and pH value affected the composition of precursors greatly.The optimum process was that NH4 Al(SO4)2 solution was added into NH4 HCO3 solution at pH 9-10 with aging time of 12h.

  6. Secondary Organic Aerosol and Brown Carbon Formation in the Sunlit Aqueous Phase: Aldehyde Photooxidation in the Presence of Ammonium Salts and Amines

    Science.gov (United States)

    De Haan, D. O.; Galloway, M. M.; Sharp, K. D.; Jiménez, N. G.

    2014-12-01

    The chemistry of water-soluble carbonyl compounds in clouds is now acknowledged as an important source of secondary organic aerosol. These reactive carbonyl compounds are oxidized to carboxylic acids and form oligomers by radical-radical reactions and by "dark reactions" with ammonium salts (AS) and/or amines. The latter class of reactions also produces light-absorbing brown carbon compounds, especially reactions involving methylglyoxal or glyoxal and amines. However, recent work has found that UV light fades the color of glyoxal + AS and methylgyloxal + AS reaction mixtures. We recently studied aldehyde-AS-amine reactions in sunlight and in control vessels at the same temperature to determine the effects of solar radiation on the aqueous-phase production of brown carbon. In sunlight, methylglyoxal reaction mixtures lost their initial color and failed to brown, indicating the photolytic loss of reactants and/or pre-brown intermediates. In many other reactions, brown products are lost to photolysis, reducing the overall browning of solutions exposed to sunlight. In other experiments, hydrogen peroxide was added to generate OH radicals by photolysis. In the presence of OH radicals, some carbonyl compound mixtures (e.g. those containing hydroxyacetone or glycolaldehyde) browned more rapidly when exposed to sunlight. This indicates the existence of uncharacterized photooxidative browning pathways involving aqueous-phase OH radicals, carbonyls, ammonium salts, and/or amine compounds.

  7. Identification of Uranyl Minerals Using Oxygen K-Edge X Ray Absorption Spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Ward, Jesse D.; Bowden, Mark E.; Resch, Charles T.; Smith, Steven C.; McNamara, Bruce K.; Buck, Edgar C.; Eiden, Gregory C.; Duffin, Andrew M.

    2016-03-01

    Uranium analysis is consistently needed throughout the fuel cycle, from mining to fuel fabrication to environmental monitoring. Although most of the world’s uranium is immobilized as pitchblende or uraninite, there exists a plethora of secondary uranium minerals, nearly all of which contain the uranyl cation. Analysis of uranyl compounds can provide clues as to a sample’s facility of origin and chemical history. X-ray absorption spectroscopy is one technique that could enhance our ability to identify uranium minerals. Although there is limited chemical information to be gained from the uranium X-ray absorption edges, recent studies have successfully used ligand NEXAFS to study the physical chemistry of various uranium compounds. This study extends the use of ligand NEXAFS to analyze a suite of uranium minerals. We find that major classes of uranyl compounds (carbonate, oxyhydroxide, silicate, and phosphate) exhibit characteristic lineshapes in the oxygen K-edge absorption spectra. As a result, this work establishes a library of reference spectra that can be used to classify unknown uranyl minerals.

  8. Solid-state dynamics of uranyl polyoxometalates.

    Science.gov (United States)

    Alam, Todd M; Liao, Zuolei; Zakharov, Lev N; Nyman, May

    2014-07-01

    Understanding fundamental uranyl polyoxometalate (POM) chemistry in solution and the solid state is the first step to defining its future role in the development of new actinide materials and separation processes that are vital to every step of the nuclear fuel cycle. Many solid-state geometries of uranyl POMs have been described, but we are only beginning to understand their chemical behavior, which thus far includes the role of templates in their self-assembly, and the dynamics of encapsulated species in solution. This study provides unprecedented detail into the exchange dynamics of the encapsulated species in the solid state through Magic Angle Spinning Nuclear Magnetic Resonance (MAS NMR) spectroscopy. Although it was previously recognized that capsule-like molybdate and uranyl POMs exchange encapsulated species when dissolved in water, analogous exchange in the solid state has not been documented, or even considered. Here, we observe the extremely high rate of transport of Li(+) and aqua species across the uranyl shell in the solid state, a process that is affected by both temperature and pore blocking by larger species. These results highlight the untapped potential of emergent f-block element materials and vesicle-like POMs.

  9. Stoichiometry of uranyl salophene anion complexes

    NARCIS (Netherlands)

    Antonisse, Martijn M.G.; Snellink-Ruel, Bianca H.M.; Engbersen, Johan F.J.; Reinhoudt, David N.

    1998-01-01

    In PVC/NPOE ion-selective membranes of potentiometric sensors, the guest-host stoichiometry of the anion complex of H2PO4 - and F- selective uranyl salophene derivatives is 2:1. This stoichiometry is different from the stoichiometry observed in DMSO solution (1H NMR) or solid state (X-ray crystal st

  10. Syntheses and structures of uranyl ethylenediphosphonates: from layers to elliptical nanochannels.

    Science.gov (United States)

    Tian, Tao; Yang, Weiting; Wang, Hao; Dang, Song; Pan, Qing-Jiang; Sun, Zhong-Ming

    2013-06-17

    A family of uranium diphosphonates have been hydrothermally synthesized through the reaction of ethylenediphosphonic acid (EDP, H4L) and uranyl nitrate/zinc uranyl acetate in the presence of organic templates, such as tetraethyl ammonium (NEt4(+)), 4,4'-bipyridine (bipy), and 1,10-phenanthroline (phen). The UO2(2+) in UO2(H2O)(H2L)(EDP-U1) is equatorially five-coordinated by four phosphonate groups and one aqua ligand, forming a pentagonal bipyramid. Each EDP ligand is doubly protonated and chelates three UO2(2+), resulting in a layered structure. Compounds (NEt4)2(UO2)3(HL)2(H2L)·4H2O (EDP-U2) and (H2bipy)UO2L (EDP-U3) have the same layered structure in which NEt4(+) and protonated bipy fill in the uranyl-phosphonate interlayers, respectively, and play a role to balance the negative charges. Different from that in EDP-U1, the UO2(2+) exists in the form of a UO6 tetragonal bipyramid and is surrounded by four different EDP ligands in EDP-U2 and EDP-U3. (Hphen)2(UO2)2(H2L)3 (EDP-U4) features a three-dimensional framework structure with large elliptical channels along the c axis (1.3 × 1.1 nm(2)). Monoprotonated phen molecules fill in these channels and hold together through strong π···π interactions. All of the four compounds have been characterized by IR and photoluminescent spectroscopy. Their characteristic emissions have been attributed as transition properties of uranyl cations. The ion-exchange study indicates that [Co(en)3](3+) could partially replace the protonated phen molecules.

  11. Expanding the crystal chemistry of uranyl peroxides: four hybrid uranyl-peroxide structures containing EDTA.

    Science.gov (United States)

    Qiu, Jie; Ling, Jie; Sieradzki, Claire; Nguyen, Kevin; Wylie, Ernest M; Szymanowski, Jennifer E S; Burns, Peter C

    2014-11-17

    The first four uranyl peroxide compounds containing ethylenediaminetetra-acetate (EDTA) were synthesized and characterized from aqueous uranyl peroxide nitrate solutions with a pH range of 5-7. Raman spectra demonstrated that reaction solutions that crystallized [NaK15[(UO2)8(O2)8(C10H12O10N2)2(C2O4)4]·(H2O)14] (1) and [Li4K6[(UO2)8(O2)6(C10H12O10N2)2(NO3)6]·(H2O)26] (2) contained excess peroxide, and their structures contained oxidized ethylenediaminetetraacetate, EDTAO2(4-). The solutions from which [K4[(UO2)4(O2)2(C10H13O8N2)2(IO3)2]·(H2O)16] (3) and LiK3[(UO2)4(O2)2(C10H12O8N2)2(H2O)2]·(H2O)18 (4) crystallized contained no free peroxide, and the structures incorporated intact EDTA(4-). In contrast to the large family of uranyl peroxide cage clusters, coordination of uranyl peroxide units in 1-4 by EDTA(4-) or EDTAO2(4-) results in isolated tetramers or dimers of uranyl ions that are bridged by bidentate peroxide groups. Two tetramers are bridged by EDTAO2(4-) to form octamers in 1 and 2, and dimers of uranyl polyhedra are linked through iodate groups in 3 and EDTA(4-) in 4, forming chains in both cases. In each structure the U-O2-U dihedral angle is strongly bent, at ∼140°, consistent with the configuration of this linkage in cage clusters and other recently reported uranyl peroxides.

  12. Micro-SHINE Uranyl Sulfate Irradiations at the Linac

    Energy Technology Data Exchange (ETDEWEB)

    Youker, Amanda J. [Argonne National Lab. (ANL), Argonne, IL (United States); Kalensky, Michael [Argonne National Lab. (ANL), Argonne, IL (United States); Chemerisov, Sergey [Argonne National Lab. (ANL), Argonne, IL (United States); Schneider, John [Argonne National Lab. (ANL), Argonne, IL (United States); Byrnes, James [Argonne National Lab. (ANL), Argonne, IL (United States); Vandegrift, George F. [Argonne National Lab. (ANL), Argonne, IL (United States)

    2016-08-01

    Peroxide formation due to water radiolysis in a uranyl sulfate solution is a concern for the SHINE Medical Technologies process in which Mo-99 is generated from the fission of dissolved low enriched uranium. To investigate the effects of power density and fission on peroxide formation and uranyl-peroxide precipitation, uranyl sulfate solutions were irradiated using a 50-MeV electron linac as part of the micro-SHINE experimental setup. Results are given for uranyl sulfate solutions with both high and low enriched uranium irradiated at different linac powers.

  13. Prokaryotic responses to ammonium and organic carbon reveal alternative CO2 fixation pathways and importance of alkaline phosphatase in the mesopelagic North Atlantic

    Directory of Open Access Journals (Sweden)

    Federico Baltar

    2016-10-01

    Full Text Available To decipher the response of mesopelagic prokaryotic communities to input of nutrients, we tracked changes in prokaryotic abundance, extracellular enzymatic activities, heterotrophic production, dark dissolved inorganic carbon (DIC fixation, community composition (16S rRNA sequencing and community gene expression (metatranscriptomics in 3 microcosm experiments with water from the mesopelagic North Atlantic. Responses in 3 different treatments amended with thiosulfate, ammonium or organic matter (i.e. pyruvate plus acetate were compared to unamended controls. The strongest stimulation was found in the organic matter enrichments, where all measured rates increased >10-fold. Strikingly, in the organic matter treatment, the dark DIC fixation rates —assumed to be related to autotrophic metabolisms— were equally stimulated as all the other heterotrophic-related parameters. This increase in DIC fixation rates was paralleled by an up-regulation of genes involved in DIC assimilation via anaplerotic pathways. Alkaline phosphatase was the metabolic rate most strongly stimulated and its activity seemed to be related to cross-activation by nonpartner histidine kinases, and/or the activation of genes involved in the regulation of elemental balance during catabolic processes. These findings suggest that episodic events such as strong sedimentation of organic matter into the mesopelagic might trigger rapid increases of originally rare members of the prokaryotic community, enhancing heterotrophic and autotrophic carbon uptake rates, ultimately affecting carbon cycling. Our experiments highlight a number of fairly unstudied microbial processes of potential importance in mesopelagic waters that require future attention.

  14. Structure-configurational entropy and its effect on the thermodynamic stability of uranyl phases: With special application for geological disposal of nuclear waste

    Institute of Scientific and Technical Information of China (English)

    CHEN; Fanrong(陈繁荣); Rodney; C.Ewing

    2003-01-01

    Spent UO2 fuel will rapidly be altered to U6+ phases in nuclear waste repositories. Because most uranyl phases are based on sheet or chain structures and usually contain several molecular water groups, site-mixing, vacancies, as well as disorder in the orientation of hydrogen bonds may occur. A systematic survey of the published crystallographic data for uranates, uranyl oxide hydrates, phosphates, silicates, carbonates, and sulfates demonstrates that site-mixing apparently occurs in the structures of at least 31 uranyl phases. Calculations of the ideal site-mixing entropy indicate that the residual contribution that arises from substitution and vacancies to the third-law entropies of some uranyl phases is large. A brief examination of the crystal chemistry of water molecules in uranyl phases suggests that considerable residual entropy may be caused by the disorder of hydrogen bonds associated with interstitial H2O groups. In the geochemical environment that expected to occur in the near-field of nuclear waste repositories, the existence of structure-configurational entropy may reduce the uranium concentration of several log units in solutions equilibrated with some uranyl phases. Therefore, compositional analysis and structural determinations must be made on the samples used in calorimetric measurements, and the calorimetric data must be combined with solubility data to evaluate the thermodynamic stability of the interested phases.

  15. The CCAAT box-binding factor stimulates ammonium assimilation in Saccharomyces cerevisiae, defining a new cross-pathway regulation between nitrogen and carbon metabolisms.

    Science.gov (United States)

    Dang, V D; Bohn, C; Bolotin-Fukuhara, M; Daignan-Fornier, B

    1996-04-01

    In Saccharomyces cerevisiae, carbon and nitrogen metabolisms are connected via the incorporation of ammonia into glutamate; this reaction is catalyzed by the NADP-dependent glutamate dehydrogenase (NADP-GDH) encoded by the GDH1 gene. In this report, we show that the GDH1 gene requires the CCAAT box-binding activator (HAP complex) for optimal expression. This conclusion is based on several lines of evidence: (1) overexpression of GDH1 can correct the growth defect of hap2 and hap3 mutants on ammonium sulfate as a nitrogen source, (ii) Northern (RNA) blot analysis shows that the steady-state level of GDH1 mRNA is strongly lowered in a hap2 mutant, (iii) expression of a GDH1-lacZ fusion is drastically reduced in hap mutants, (iv) NADP-GDH activity is several times lower in the hap mutants compared with that in the isogenic wild-type strain, and finally, (v) site-directed mutagenesis of two consensual HAP binding sites in the GDH1 promoter strongly reduces expression of GDH1 and makes it HAP independent. Expression of GDH1 is also regulated by the carbon source, i.e., expression is higher on lactate than on ethanol, glycerol, or galactose, with the lowest expression being found on glucose. Finally, we show that a hap2 mutation does not affect expression of other genes involved in nitrogen metabolism (GDH2, GLN1, and GLN3 encoding, respectively, the NAD-GDH, glutamine synthetase, and a general activator of several nitrogen catabolic genes). The HAP complex is known to regulate expression of several genes involved in carbon metabolism; its role in the control of GDH1 gene expression, therefore, provides evidence for a cross-pathway regulation between carbon and nitrogen metabolisms.

  16. DNA conformational analysis in solution by uranyl mediated photocleavage

    DEFF Research Database (Denmark)

    Nielsen, Peter E.; Møllegaard, N E; Jeppesen, C

    1990-01-01

    by uranyl in a way indicating strongest uranyl binding at the center of the minor groove of the AT-region. The A-tracts of kinetoplast DNA show the highest reactivity at the 3'-end of the tract--as opposed to cleavage by EDTA/Fell--in accordance with the minor groove being more narrow at this end. Finally...

  17. A Chitosan Derivative Containing Both Carboxylic Acid and Quaternary Ammonium Moieties for the Synthesis of Cyclic Carbonates.

    Science.gov (United States)

    Besse, Vincent; Illy, Nicolas; David, Ghislain; Caillol, Sylvain; Boutevin, Bernard

    2016-08-23

    Chitosan, a renewable feedstock, is modified and used as a catalytic support in the presence of potassium iodide. The system is highly efficient towards the incorporation of carbon dioxide (CO2 ) into epoxides. It demonstrates very good thermal stability and is recyclable more than five times without loss of activity. The optimal reaction conditions were determined using allylglycidyl ether as a model and extended to a wide range of other epoxides. Cyclic carbonates were obtained with very high yield in a few hours under mild conditions (2-7 bar≈0.2-0.7 MPa, 80 °C) and no solvent.

  18. 钆元素在碳酸钠、碳酸氢铵溶液中溶解性研究%Study of Solubility of Gadolinium in Sodium Carbonate and Ammonium Bicarbonate Solution

    Institute of Scientific and Technical Information of China (English)

    赵永志; 郝先库; 张瑞祥; 胡珊珊; 马显东; 许宗泽

    2013-01-01

    In this paper, the solubility of gadolinium in sodium carbonate and ammonium bicarbonate was studied. As a result, the solubility increased then decreased with reaction time. The solubility was improved by increasing carbonate concentration. With the increasing temperature, the solubility increased in sodium carbonate but decreased in ammonium bicarbonate solution. The solubility of gadolinium increased in anmmonium bicarbonate but decreased in sodium carbonate with addition of ammonium hydroxide.%研究了钆元素在碳酸钠、碳酸氢铵溶液中的溶解性.钆元素在碳酸钠、碳酸氢铵溶液中随着反应时间的延长溶解量先增大后减小;提高碳酸钠和碳酸氢铵浓度也可以增加钆元素的溶解量;反应温度对钆元素在碳酸钠和碳酸氢铵溶液中的溶解性影响不同,表现为温度升高,钆在碳酸氢铵溶液中的溶解量减小,在碳酸钠溶液中增大.在碳酸氢铵溶液中加入氨水可以增大钆的溶解量,而在碳酸钠溶液中加入氢氧化钠使钆的溶解量减小.

  19. Structure and spectroscopy of uranyl salicylaldiminate complexes

    Energy Technology Data Exchange (ETDEWEB)

    Tamasi, A.L.; Barnes, C.L.; Walensky, J.R. [Missouri Univ., Columbia, MO (United States). Dept. of Chemistry

    2013-07-01

    The synthesis of uranyl complexes coordinated to tridentate, monoanionic salicylaldiminate (Schiff base) ligands was achieved by the reaction of UO{sub 2}Cl{sub 2}(THF){sub 3}, 1, with one equivalent of the corresponding sodium salicylaldiminate salts affording [(C{sub 9}H{sub 6}N)N=C(H)C{sub 6}H{sub 2}'Bu{sub 2}O]UO{sub 2}Cl(THF), 2, [(NC{sub 5}H{sub 4})N=C(H)C{sub 6}H{sub 2}'Bu{sub 2}O]UO{sub 2}Cl(THF), 3, and [(C{sub 6}H{sub 4}SCH{sub 3})N=C(H)C{sub 6}H{sub 2}'Bu{sub 2}O]UO{sub 2}Cl(THF), 4. These are uncommon examples of uranyl complexes with a monoanionic ancillary ligand to stabilize the coordination sphere and one chloride ligand. Compounds 2-4 have been characterized by {sup 1}H and {sup 13}C NMR spectroscopy as well as IR and UVVis spectroscopy and their structures determined by X-ray crystallography. (orig.)

  20. Sulfur and nitrogen binary doped carbon dots derived from ammonium thiocyanate for selective probing doxycycline in living cells and multicolor cell imaging.

    Science.gov (United States)

    Xue, Mingyue; Zhang, Liangliang; Zhan, Zhihua; Zou, Mengbing; Huang, Yong; Zhao, Shulin

    2016-04-01

    A novel sulfur and nitrogen binary doped carbon dots (S,N-CDs) was synthesized by one-step manner through the hydrothermal treatment of citric acid (CA) and ammonium thiocyanate, and the procedures for biomedical applications, including probing doxycycline in living cells and multicolor cell imaging were developed. The obtained S,N-CDs are stable in aqueous solution, possess a very high quantum yield (QY, 74.15%) and good photostability. The fluorescence of S,N-CDs can be specifically quenched by doxycycline, providing a convenient turn-off assay of doxycycline. This assay shows a wide linear detection range from 0.08 to 60 μM with a low detection limit of 20 nM. The present method also displays a good selectivity. More importantly, the S,N-CDs have an excellent biocompatibility and low cytotoxicity, allowing the multicolor cell imaging and doxycycline detection in living cells. Consequently, the developed doxycycline methods is facile, low-cost, biocompatible, sensitive and selective, which may hold the potential applications in the fields of food safety and environmental monitoring, as well as cancer therapy and related mechanism research.

  1. Bifunctional quaternary ammonium compounds to inhibit biofilm growth and enhance performance for activated carbon air-cathode in microbial fuel cells

    Science.gov (United States)

    Li, Nan; Liu, Yinan; An, Jingkun; Feng, Cuijuan; Wang, Xin

    2014-12-01

    The slow diffusion of hydroxyl out of the catalyst layer as well as the biofouling on the surface of cathode are two problems affecting power for membrane-less air-cathode microbial fuel cells (MFCs). In order to solve both of them simultaneously, here we simply modify activated carbon air-cathode using a bifunctional quaternary ammonium compound (QAC) by forced evaporation. The maximum power density reaches 1041 ± 12 mW m-2 in an unbuffered medium (0.5 g L-1 NaCl), which is 17% higher than the control, probably due to the accelerated anion transport in the catalyst layer. After 2 months, the protein content reduced by a factor of 26 and the power density increases by 33%, indicating that the QAC modification can effectively inhibit the growth of cathodic biofilm and improve the stability of performance. The addition of NaOH and QAC epoxy have a negative effect on power production due to the clogging of pores in catalyst layer.

  2. Uranyl-oxo coordination directed by non-covalent interactions.

    Science.gov (United States)

    Lewis, Andrew J; Yin, Haolin; Carroll, Patrick J; Schelter, Eric J

    2014-07-28

    Directed coordination of weakly Lewis acidic K(+) ions to weakly Lewis basic uranyl oxo ligands is accomplished through non-covalent cation-π and cation-F interactions for the first time. Comparison of a family of structurally related diarylamide ligands highlights the role that the cation-π and cation-F interactions play in guiding coordination. Cation binding to uranyl is demonstrated in the solid state and in solution, providing the shortest reported crystallographic uranyl-oxo to potassium distance. UV-Vis, TD-DFT calculations, and electrochemical measurements show that cation coordination directly impacts the electronics at the uranium(vi) cation.

  3. Insensitive Ammonium Nitrate.

    Science.gov (United States)

    is reduced by replacing the ammonium nitrate with a solid solution of potassium nitrate in form III ammonium nitrate wherein the potassium nitrate...constitutes from more than zero to less than 50 weight percent of the solid solution . (Author)

  4. Thorium adsorption behaviour on mixed ammonium lanthanum oxalate, LAOX

    Energy Technology Data Exchange (ETDEWEB)

    Valentini Ganzerli, M.T.; Maggi, L.; Crespi Caramella, V

    1999-07-01

    The cation-exchange properties of mixed ammonium lanthanum oxalate, LAOX, were studied by batch equilibration as a function of the concentration of some cations, such as alkaline earths or ammonium and of some anions and acids. The distribution coefficients for thorium are high, while U(VI) is not adsorbed over a large acidity range. Thus, the separation of thorium from uranium may be successfully carried out. The experimental conditions of adsorption, elution and recovery of thorium were investigated as well, by using chromatographic columns filled with LAOX, in order to set best the separation conditions from uranyl ions. Instrumental neutron activation analysis, ICP emission spectrometry and the UV spectrometry were used to evaluate the thorium, uranium and lanthanum concentrations00.

  5. 低碳链季铵盐定量分析方法的改进%Improvement of quantitative analysis method for short-carbon-chain quaternary ammonium salt

    Institute of Scientific and Technical Information of China (English)

    吴文桢; 屈撑囤; 张世君; 杨志刚

    2009-01-01

    In order to make quantitative analysis for the short-carbon-chain quaternary ammonium salt, the method of "dodecyl dimethyl ammonium chloride quantitative analysis" in the standard(HG/T2230-2006)was improved and investigated by adopting the sodium tetraphenyl boron back titrimetry. Based on gravimetric method, the accuracy of the analysis results was inspected. According to the error analysis of the measuring results, the reproducibility of this improved method was discussed. Meanwhile, the different-carbon-chain quaternary ammonium salt was quantitatively analyzed. The result shows that as the mass fraction of short-carbon-chain quaternary ammonium salt molecular is more than 0.1%, the sodium tetraphenyl boron back titrimetry that improves the method in HG/T2230-2006 has good accuracy and repeatability, the accuracy rate of analysis result is above 99.5 %.%为了对低碳链季铵盐进行定量分析,应用四苯硼钠返滴定法对(HG/T 2230-2006)标准中低碳链季铵盐质量分数进行了分析改进研究.以重量法为基准对分析结果的准确性进行了检验,通过测定结果的误差分析,对方法的重现性进行了探讨,同时对不同碳链季铵盐进行了定量分析.结果表明,当低碳链季铵盐分子的质量分数在0.1%以上时,应用(HG/T 2230-2006)标准分析低碳链季铵盐质量分数的改进方法重现性好,准确率为99.5%以上.

  6. 氯化铵处理电石渣制备纳米碳酸钙的实验研究%Experimental Study on Preparation of Nanosized Calcium Carbonate from Carbide Slag Treated by Ammonium Chloride

    Institute of Scientific and Technical Information of China (English)

    张爱华; 朱敏; 关云山; 李晓昆; 张志强; 崔小琴

    2013-01-01

    采用氯化铵对电石渣进行除杂、碳化制备了纳米碳酸钙.优化实验结果表明:干燥温度105℃、pH =8、反应时间1h、氯化铵溶液浓度8%、氯化铵过量程度30%的条件下电石渣收率达92%以上.XRD分析表明产品为方解石,平均晶粒尺寸为38 nm,SEM表明平均颗粒径为80 nm.%The preparation of nanosized calcium carbonate is carried by impurity removal and carbonization of carbide slag treated by ammonium chloride. The optimize experimental results show that carbide slag yield can reach over 92% by controlling drying temperature for 105℃ , pH =8, reaction time for 1 h, concentration of ammonium chloride for 8% and excessive degree of ammonium chloride for 30%. Furthermore, the XRD results showed the production is calcite and the grain average size is 38 nm. And the average particle size in SEM is about 80 nm.

  7. Elevated ammonium levels

    DEFF Research Database (Denmark)

    Søgaard, Rikke; Novak, Ivana; MacAulay, Nanna

    2012-01-01

    ]glutamate uptake and glutamate transport currents but had no effect on EAAT2. The maximal EAAT3-mediated glutamate transport current was increased but the apparent affinities for glutamate and Na(+) were unaltered. Ammonium did not affect EAAT3-mediated transient currents, indicating that EAAT3 surface expression...... was not enhanced. The ammonium-induced stimulation of EAAT3 increased with increasing extracellular pH, suggesting that the gaseous form NH(3) mediates the effect. An ammonium-induced intracellular alkalinization was excluded as the cause of the enhanced EAAT3 activity because 1) ammonium acidified the oocyte...... cytoplasm, 2) intracellular pH buffering with MOPS did not reduce the stimulation, and 3) ammonium enhanced pH-independent cysteine transport. Our data suggest that the ammonium-elicited uptake stimulation is not caused by intracellular alkalinization or changes in the concentrations of cotransported ions...

  8. A Phosphorylation Tag for Uranyl Mediated Protein Purification and Photo Assisted Tag Removal

    DEFF Research Database (Denmark)

    Zhang, Qiang; Jørgensen, Thomas. J. D.; Nielsen, Peter E;

    2014-01-01

    enables target protein purification from an E. coli extract by immobilized uranyl affinity chromatography. Subsequently, the tag can be efficiently removed by UV-irradiation assisted uranyl photocleavage. We therefore suggest that the divalent uranyl ion (UO22+) may provide a dual function in protein...

  9. The catalytic role of uranyl in formation of polycatechol complexes

    Directory of Open Access Journals (Sweden)

    Halada Gary P

    2011-03-01

    Full Text Available Abstract To better understand the association of contaminant uranium with natural organic matter (NOM and the fate of uranium in ground water, spectroscopic studies of uranium complexation with catechol were conducted. Catechol provides a model for ubiquitous functional groups present in NOM. Liquid samples were analyzed using Raman, FTIR, and UV-Vis spectroscopy. Catechol was found to polymerize in presence of uranyl ions. Polymerization in presence of uranyl was compared to reactions in the presence of molybdate, another oxyion, and self polymerization of catechol at high pH. The effect of time and dissolved oxygen were also studied. It was found that oxygen was required for self-polymerization at elevated pH. The potential formation of phenoxy radicals as well as quinones was monitored. The benzene ring was found to be intact after polymerization. No evidence for formation of ether bonds was found, suggesting polymerization was due to formation of C-C bonds between catechol ligands. Uranyl was found to form outer sphere complexes with catechol at initial stages but over time (six months polycatechol complexes were formed and precipitated from solution (forming humic-like material while uranyl ions remained in solution. Our studies show that uranyl acts as a catalyst in catechol-polymerization.

  10. Ammonium sulfate preparation from phosphogypsum waste

    Directory of Open Access Journals (Sweden)

    Abdel-Hakim T. Kandil

    2017-01-01

    Full Text Available The Egyptian phosphogypsum waste is treated using sulfuric acid prior the ammonium sulfate production. The relevant factors that would affect the removal efficiencies of some impurities are studied. The optimum conditions of the treatment are 8 M sulfuric acid solution and 1/4 solid/liquid ratio for 30 min contact time at 80 °C. Moreover, the optimum conditions of the ammonium sulfate preparation are 10 g of the suspended impure or purified phosphogypsum in 40 ml of 3% ammonium sulfate solution (as initiator, 1/4 solid/liquid ratio at pH7 at an addition of an excess ammonium carbonate, and 150 rpm stirring speed for 4.0 h contact time at 55 °C as well as the 5 mg of barium chloride is added to remove the radium in the ammonium sulfate product. Finally, the ammonium sulfate is crystallized and the chemical analysis of the product shows 20% nitrogen and 23.6% sulfur. Therefore, the purity of the obtained ammonium sulfate is 95% from the purified phosphogypsum.

  11. Rate theory on water exchange in aqueous uranyl ion

    Science.gov (United States)

    Dang, Liem X.; Vo, Quynh N.; Nilsson, Mikael; Nguyen, Hung D.

    2017-03-01

    We report a classical rate theory approach to predict the exchange mechanism that occurs between water and aqueous uranyl ion. Using our water and ion-water polarizable force field and molecular dynamics techniques, we computed the potentials of mean force for the uranyl ion-water pair as a function of different pressures at ambient temperature. These potentials of mean force were used to calculate rate constants using transition rate theory; the transmission coefficients also were examined using the reactive flux method and Grote-Hynes approach. The computed activation volumes are positive; thus, the mechanism of this particular water-exchange is a dissociative process.

  12. Isotope selectivity of infrared laser-driven unimolecular dissociation of a volatile uranyl compound.

    Science.gov (United States)

    Cox, D M; Hall, R B; Horsley, J A; Kramer, G M; Rabinowitz, P; Kaldor, A

    1979-07-27

    Isotope-selective photodissociation of the volatile complex uranyl hexafluoroacetylacetonate . tetrahydrofuran [UO(2)(hfacac)(2) . THF] has been achieved with both a continuous-wave and a pulsed carbon dioxide laser. The photodissociation was carried out in a low-density molecular beam under collisionless conditions. Transitions of the laser are in resonance with the asymmetric O-U-O stretch of the uranyl moiety, a vibrational mode whose frequency is sensitive to the masses of the uranium and oxygen isotopes. Unimolecular dissociation is observed mass spectrometrically at an extremely low energy fluence, with no evidence of an energy fluence or intensity threshold. The dissociation yield increases nearly linearly with increasing energy fluence. At constant fluence the dissociation yield is independent of contact time between the radiation field and the molecule, indicating that the decomposition is driven by laser energy fluence and not laser intensity. The oxygen and uranium isotope selectivities measured in these experiments are nearly those predicted by the ratio of the linear absorption cross sections for the respective isotopes. Thus, essentially complete selectivity is observed for oxygen isotopes, while a selectivity of only about 1.25 is measured for the uranium isotopes. A model presented to describe these results is based on rapid intramolecular vibrational energy flow from the pumped mode into a limited number of closely coupled modes.

  13. Gas Phase Reactions of Ions Derived from Anionic Uranyl Formate and Uranyl Acetate Complexes

    Science.gov (United States)

    Perez, Evan; Hanley, Cassandra; Koehler, Stephen; Pestok, Jordan; Polonsky, Nevo; Van Stipdonk, Michael

    2016-12-01

    The speciation and reactivity of uranium are topics of sustained interest because of their importance to the development of nuclear fuel processing methods, and a more complete understanding of the factors that govern the mobility and fate of the element in the environment. Tandem mass spectrometry can be used to examine the intrinsic reactivity (i.e., free from influence of solvent and other condensed phase effects) of a wide range of metal ion complexes in a species-specific fashion. Here, electrospray ionization, collision-induced dissociation, and gas-phase ion-molecule reactions were used to create and characterize ions derived from precursors composed of uranyl cation (UVIO2 2+) coordinated by formate or acetate ligands. Anionic complexes containing UVIO2 2+ and formate ligands fragment by decarboxylation and elimination of CH2=O, ultimately to produce an oxo-hydride species [UVIO2(O)(H)]-. Cationic species ultimately dissociate to make [UVIO2(OH)]+. Anionic complexes containing acetate ligands exhibit an initial loss of acetyloxyl radical, CH3CO2•, with associated reduction of uranyl to UVO2 +. Subsequent CID steps cause elimination of CO2 and CH4, ultimately to produce [UVO2(O)]-. Loss of CH4 occurs by an intra-complex H+ transfer process that leaves UVO2 + coordinated by acetate and acetate enolate ligands. A subsequent dissociation step causes elimination of CH2=C=O to leave [UVO2(O)]-. Elimination of CH4 is also observed as a result of hydrolysis caused by ion-molecule reaction with H2O. The reactions of other anionic species with gas-phase H2O create hydroxyl products, presumably through the elimination of H2.

  14. Thermodynamics of Uranyl Minerals: Enthalpies of Formation of Uranyl Oxide Hydrates

    Energy Technology Data Exchange (ETDEWEB)

    K. Kubatko; K. Helean; A. Navrotsky; P.C. Burns

    2005-05-11

    The enthalpies of formation of seven uranyl oxide hydrate phases and one uranate have been determined using high-temperature oxide melt solution calorimetry: [(UO{sub 2}){sub 4}O(OH){sub 6}](H{sub 2}O){sub 5}, metaschoepite; {beta}-UO{sub 2}(OH){sub 2}; CaUO{sub 4}; Ca(UO{sub 2}){sub 6}O{sub 4}(OH){sub 6}(H{sub 2}O){sub 8}, becquerelite; Ca(UO{sub 2}){sub 4}O{sub 3}(OH){sub 4}(H{sub 2}O){sub 2}; Na(UO{sub 2})O(OH), clarkeite; Na{sub 2}(UO{sub 2}){sub 6}O{sub 4}(OH){sub 6}(H{sub 2}O){sub 7}, the sodium analogue of compreignacite and Pb{sub 3}(UO{sub 2}){sub 8}O{sub 8}(OH){sub 6}(H{sub 2}O){sub 2}, curite. The enthalpy of formation from the binary oxides, {Delta}H{sub f-ox}, at 298 K was calculated for each compound from the respective drop solution enthalpy, {Delta}H{sub ds}. The standard enthalpies of formation from the elements, {Delta}H{sub f}{sup o}, at 298 K are -1791.0 {+-} 3.2, -1536.2 {+-} 2.8, -2002.0 {+-} 3.2, -11389.2 {+-} 13.5, -6653.1 {+-} 13.8, -1724.7 {+-} 5.1, -10936.4 {+-} 14.5 and -13163.2 {+-} 34.4 kJ mol{sup -1}, respectively. These values are useful in exploring the stability of uranyl oxide hydrates in auxiliary chemical systems, such as those expected in U-contaminated environments.

  15. How to make a living from anaerobic ammonium oxidation

    NARCIS (Netherlands)

    Kartal, B.; De Almeida, N.M.; Maalcke, W.J.; Op den Camp, H.J.M.; Jetten, M.S.M.; Keltjens, J.T.

    2013-01-01

    Anaerobic ammonium-oxidizing (anammox) bacteria primarily grow by the oxidation of ammonium coupled to nitrite reduction, using CO2 as the sole carbon source. Although they were neglected for a long time, anammox bacteria are encountered in an enormous species (micro)diversity in virtually any anoxi

  16. Ligand size dependence of U-N and U-O bond character in a series of uranyl hexaphyrin complexes: quantum chemical simulation and density based analysis.

    Science.gov (United States)

    Di Pietro, Poppy; Kerridge, Andrew

    2017-03-02

    A series of uranyl complexes with hexaphyrin ligands are investigated at the density functional level of theory and analysed using a variety of density-based techniques. A relationship is identified between the size of the ligand and the stability of the complex, controlled by the presence of meso-carbon centres in the porphyrin ring. The complex with the smallest ligand, cyclo[6]pyrrole, is found to have enhanced covalent character in equatorial U-N bonds as defined by the quantum theory of atoms in molecules (QTAIM), as well as enhanced stability, compared to the larger complexes. QTAIM data are supported by electron density difference distributions, integrated electronic properties and analysis of the reduced density gradient (RDG), which all show unambiguous evidence of electron sharing in all U-N bonds. In all complexes, a weakening of the covalent axial U-Oyl interaction in comparison to free uranyl is found, with evidence for a separation of electronic charge resulting in a more ionic interaction. A relationship between covalent character in the U-N bonds and the magnitude of uranyl charge redistribution is identified, where the greater the covalent character of the U-N interaction, the more ionic the U-Oyl interaction appears. The complex with the largest ligand, hexaphyrin(1.1.1.1.1.1), is found to have additional interactions with the uranyl oxygen centres, perturbing the U-Oyl interaction.

  17. Colorimetric peroxidase mimetic assay for uranyl detection in sea water

    KAUST Repository

    Zhang, Dingyuan

    2015-03-04

    Uranyl (UO2 2+) is a form of uranium in aqueous solution that represents the greatest risk to human health because of its bioavailability. Different sensing techniques have been used with very sensitive detection limits especially the recently reported uranyl-specific DNAzymes systems. However, to the best of our knowledge, few efficient detection methods have been reported for uranyl sensing in seawater. Herein, gold nanoclusters (AuNCs) are employed in an efficient spectroscopic method to detect uranyl ion (UO2 2+) with a detection limit of 1.86 ÎM. In the absence of UO2 2+, the BSA-stabilized AuNCs (BSA-AuNCs) showed an intrinsic peroxidase-like activity. In the presence of UO2 2+, this activity can be efficiently restrained. The preliminary quenching mechanism and selectivity of UO2 2+ was also investigated and compared with other ions. This design strategy could be useful in understanding the binding affinity of protein-stabilized AuNCs to UO2 2+ and consequently prompt the recycling of UO2 2+ from seawater.

  18. Durable phosphate-selective electrodes based on uranyl salophenes

    NARCIS (Netherlands)

    Wroblewski, Wojciech; Wojciechowski, Kamil; Dybko, Artur; Brzozka, Zbigniew; Egberink, Richard J.M.; Snellink-Ruel, Bianca H.M.; Reinhoudt, David N.

    2001-01-01

    Lipophilic uranyl salophenes derivatives were used as ionophores in durable phosphate-selective electrodes. The influence of the ionophore structure and membrane composition (polarity of plasticizer, the amount of incorporated ionic sites) on the electrode selectivity and long-term stability were st

  19. Multi-scale modelling of uranyl chloride solutions

    Energy Technology Data Exchange (ETDEWEB)

    Nguyen, Thanh-Nghi; Duvail, Magali, E-mail: magali.duvail@icsm.fr; Villard, Arnaud; Dufrêche, Jean-François, E-mail: jean-francois.dufreche@univ-montp2.fr [Institut de Chimie Séparative de Marcoule (ICSM), UMR 5257, CEA-CNRS-Université Montpellier 2-ENSCM, Site de Marcoule, Bâtiment 426, BP 17171, F-30207 Bagnols-sur-Cèze Cedex (France); Molina, John Jairo [Fukui Institute for Fundamental Chemistry, Kyoto University, Takano-Nishihiraki-cho 34-4, Sakyo-ku, Kyoto 606-8103 (Japan); Guilbaud, Philippe [CEA/DEN/DRCP/SMCS/LILA, Marcoule, F-30207 Bagnols-sur-Cèze Cedex (France)

    2015-01-14

    Classical molecular dynamics simulations with explicit polarization have been successfully used to determine the structural and thermodynamic properties of binary aqueous solutions of uranyl chloride (UO{sub 2}Cl{sub 2}). Concentrated aqueous solutions of uranyl chloride have been studied to determine the hydration properties and the ion-ion interactions. The bond distances and the coordination number of the hydrated uranyl are in good agreement with available experimental data. Two stable positions of chloride in the second hydration shell of uranyl have been identified. The UO{sub 2}{sup 2+}-Cl{sup −} association constants have also been calculated using a multi-scale approach. First, the ion-ion potential averaged over the solvent configurations at infinite dilution (McMillan-Mayer potential) was calculated to establish the dissociation/association processes of UO{sub 2}{sup 2+}-Cl{sup −} ion pairs in aqueous solution. Then, the association constant was calculated from this potential. The value we obtained for the association constant is in good agreement with the experimental result (K{sub UO{sub 2Cl{sup +}}} = 1.48 l mol{sup −1}), but the resulting activity coefficient appears to be too low at molar concentration.

  20. Polaron effects in the protonic conductor hydrogen uranyl phosphate

    Energy Technology Data Exchange (ETDEWEB)

    Lupu, D. (Inst. of Isotopic and Molecular Technology, Cluj-Napoca (Romania)); Grecu, R. (Inst. of Chemistry, Cluj-Napoca (Romania)); Biris, A.R. (Inst. of Isotopic and Molecular Technology, Cluj-Napoca (Romania))

    1993-08-01

    The isotope effects on the conductivity of hydrogen uranyl phosphate reveal ionic polaron effects in this solid protonic conductor, in agreement with the small polaron theory. An absorption band is observed at 0.67 eV, which can be correlated with the conduction mechanism consisting in both tunnelling and over-barrier hopping processes. (orig.)

  1. Residual biomass for removal of uranyl ions;Biomassa residual para remocao de ions uranilo

    Energy Technology Data Exchange (ETDEWEB)

    Boniolo, Milena Rodrigues [Universidade Federal de Sao Carlos (UFScar), SP (Brazil). Dept. de Biogeoquimica Ambiental; Yamaura, Mitiko; Monteiro, Raquel Almeida, E-mail: milenaboniolo@usp.b [Instituto de Pesquisas Energeticas e Nucleares (IPEN/CNEN-SP), Sao Paulo, SP (Brazil). Centro de Quimica e Meio Ambiente

    2010-07-01

    Activities related to nuclear industry, production of phosphoric acid and hospitals have generated considerable volumes of radioactive waste containing uranyl ions. Banana pith was characterized by scanning electron microscopy and Fourier transform infrared spectroscopy and was investigated as a biosorbent for uranyl ions from nitric solutions by batch experiments. Influences of adsorbent size, kinetics and equilibrium adsorption were studied. The biosorption of the uranyl ions followed pseudo-second-order kinetics. The adsorption isotherm data were closely fitted to the Freundlich equation. (author)

  2. Adsorption of uranyl ion on acid-modified zeolitic mineral clinoptilolite

    Directory of Open Access Journals (Sweden)

    Matijašević Srđan D.

    2009-01-01

    Full Text Available In this paper, the results of adsorption of uranyl ion on acid-modified zeolitic mineral clinoptilolite are presented. Adsorption was investigated at different amounts of solid phase in suspension, as well as at different pH values. The modified clinoptilolite samples were obtained by treatment of clinoptilolite with acids: hydrochloric, oxalyc and citric. Starting and modified clinoptilolites were characterized by chemical analysis, thermal (DT/TG analysis and by determination of cation exchange capacity, while starting and nonadsorbed amounts of uranyl ion were determined by fluorometric method. Uranyl ion adsorption experiments on natural unmodified zeolitic mineral showed that uranyl ion adsorption was low (29.2% and that treatment of clinoptilolite with acids significantly increases the adsorption of uranyl ion (>90%. In the case of acid treated clinoptilolites, the highest adsorption of uranyl ion was achieved on clinoptilolite modified with hydrochloric acid. Kinetics of adsorption showed that adsorption of uranyl ion begins very fast and that the most of uranyl ion was adsorbed in first 30 min. Practically, there were no changes in uranyl ion adsorption within next 72 h.

  3. Electrochemical uranyl cation biosensor with DNA oligonucleotides as receptor layer.

    Science.gov (United States)

    Jarczewska, Marta; Ziółkowski, Robert; Górski, Łukasz; Malinowska, Elżbieta

    2014-04-01

    The present study aims at the further development of the uranyl oligonucleotide-based voltammetric biosensor, which takes advantage of strong interaction between UO2(2+) and phosphate DNA backbone. Herein we report the optimization of working parameters of previously elaborated electrochemical DNA biosensor. It is shown that the sensor sensitivity is highly dependent on the oligonucleotide probe length and the incubation time of sensor in a sample solution. Consequently, the highest sensitivity was obtained for 10-nucleotide sequence and 60 min incubation time. The lower detection limit towards uranyl cation for developed biosensor was 30 nM. The influence of mixed monolayers and the possibility of developing a non-calibration device were also investigated. The selectivity of the proposed biosensor was significantly improved via elimination of adenine nucleobases from the DNA probe. Moreover, the regeneration procedure was elaborated and tested to prolong the use of the same biosensor for 4 subsequent determinations of UO2(2+).

  4. Structure and bonding in crystalline cesium uranyl tetrachloride under pressure.

    Science.gov (United States)

    Osman, Hussien H; Pertierra, Pilar; Salvadó, Miguel A; Izquierdo-Ruiz, F; Recio, J M

    2016-07-21

    A thorough investigation of pressure effects on the structural properties of crystalline cesium uranyl chloride was performed by means of first-principles calculations within the density functional theory framework. Total energies, equilibrium geometries and vibrational frequencies were computed at selected pressures up to 50 GPa. Zero pressure results present good agreement with available experimental and theoretical data. Our calculated equation of state parameters reveal that Cs2UO2Cl4 is a high compressible material, similar to other ionic compounds with cesium cations, and displays a structural anisotropic behavior guided by the uranyl moiety. An unexpected variation of the U-O bond length, dUO, is detected as pressure is applied. It leads to a dUO-stretching frequency relationship that cannot be described by the traditional Badger's rule. Interestingly enough, it can be explained in terms of a change in the main factor controlling dUO. At low pressure, the charge transferred to the uranyl cation induces an increase of the bond length and a red shift of the stretching frequencies, whereas it is the mechanical effect of the applied pressure above 10 GPa that is the dominant factor that leads to a shortening of dUO and a blue shift of the stretching frequencies.

  5. Synthesis of phosphorylated calix[4]arene derivatives for the design of solid phases immobilizing uranyl cations

    Energy Technology Data Exchange (ETDEWEB)

    Maroun, E.B.; Hagege, A.; Asfari, Z. [Laboratoire de Chimie Analytique et Minerale, UMR 7178 ULP/CNRS/IN2P3 LC4, ECPM, Strasbourg Cedex (France); Basset, CH.; Quemeneur, E.; Vidaud, C. [CEA IBEB, SBTN, Centre de Marcoule, Bagnols-sur-Ceze (France)

    2009-07-01

    With the aim of developing supports for uranyl cations immobilisation, new 1, 3-alternate calix[4]arenes bearing both phosphonic acid functions as chelating sites and N-succinimide-4-oxa-butyrate as the anchoring arm were synthesised in good yields. The coupling of such calixarenes to a gel was performed and a successful immobilisation of uranyl cations was obtained. (authors)

  6. Production and Characterization of Desmalonichrome Relative Binding Affinity for Uranyl Ions in Relation to Other Siderophores

    Energy Technology Data Exchange (ETDEWEB)

    Mo, Kai-For; Dai, Ziyu; Wunschel, David S.

    2016-06-24

    Siderophores are Fe binding secondary metabolites that have been investigated for their uranium binding properties. Much of the previous work has focused on characterizing hydroxamate types of siderophores, such as desferrioxamine B, for their uranyl binding affinity. Carboxylate forms of these metabolites hold potential to be more efficient chelators of uranyl, yet they have not been widely studied and are more difficult to obtain. Desmalonichrome is a carboxylate siderophore which is not commercially available and so was obtained from the ascomycete fungus Fusarium oxysporum cultivated under Fe depleted conditions. The relative affinity for uranyl binding of desmalonichrome was investigated using a competitive analysis of binding affinities between uranyl acetate and different concentrations of iron(III) chloride using electrospray ionization mass spectrometry (ESI-MS). In addition to desmalonichrome, three other siderophores, including two hydroxamates (desferrioxamine B and desferrichrome) and one carboxylate (desferrichrome A) were studied to understand their relative affinities for the uranyl ion at two pH values. The binding affinities of hydroxymate siderophores to uranyl ion were found to decrease to a greater degree at lower pH as the concentration of Fe (III) ion increases. On the other hand, lowering pH has little impact on the binding affinities between carboxylate siderophores and uranyl ion. Desmalonichrome was shown to have the greatest relative affinity for uranyl at any pH and Fe(III) concentration. These results suggest that acidic functional groups in the ligands are critical for strong chelation with uranium at lower pH.

  7. Quantification of uranyl in presence of citric acid; Cuantificacion de uranilo en presencia de acido citrico

    Energy Technology Data Exchange (ETDEWEB)

    Garcia G, N.; Barrera D, C.E. [UAEM, Facultad de Quimica, 50000 Toluca, Estado de Mexico (Mexico); Ordonez R, E. [ININ, 52750 La Marquesa, Estado de Mexico (Mexico)]. e-mail: nidgg@yahoo.com.mx

    2007-07-01

    To determine the influence that has the organic matter of the soil on the uranyl sorption on some solids is necessary to have a detection technique and quantification of uranyl that it is reliable and sufficiently quick in the obtaining of results. For that in this work, it intends to carry out the uranyl quantification in presence of citric acid modifying the Fluorescence induced by UV-Vis radiation technique. Since the uranyl ion is very sensitive to the medium that contains it, (speciation, pH, ionic forces, etc.) it was necessary to develop an analysis technique that stands out the fluorescence of uranyl ion avoiding the out one that produce the organic acids. (Author)

  8. Overexpressing of OsAMT1-3, a High Affinity Ammonium Transporter Gene, Modifies Rice Growth and Carbon-Nitrogen Metabolic Status

    Directory of Open Access Journals (Sweden)

    Aili Bao

    2015-04-01

    Full Text Available AMT1-3 encodes the high affinity NH4+ transporter in rice roots and is predominantly expressed under nitrogen starvation. In order to evaluate the effect of AMT1-3 gene on rice growth, nitrogen absorption and metabolism, we generated AMT1-3-overexpressing plants and analyzed the growth phenotype, yield, carbon and nitrogen metabolic status, and gene expression profiles. Although AMT1-3 mRNA accumulated in transgenic plants, these plants displayed significant decreases in growth when compared to the wild-type plants. The nitrogen uptake assay using a 15N tracer revealed poor nitrogen uptake ability in AMT1-3-overexpressing plants. We found significant decreases in AMT1-3-overexpressing plant leaf carbon and nitrogen content accompanied with a higher leaf C/N ratio. Significant changes in soluble proteins and carbohydrates were also observed in AMT1-3-overexpressing plants. In addition, metabolite profile analysis demonstrated significant changes in individual sugars, organic acids and free amino acids. Gene expression analysis revealed distinct expression patterns of genes that participate in carbon and nitrogen metabolism. Additionally, the correlation between the metabolites and gene expression patterns was consistent in AMT1-3-overexpressing plants under both low and high nitrogen growth conditions. Therefore, we hypothesized that the carbon and nitrogen metabolic imbalance caused by AMT1-3 overexpressing attributed to the poor growth and yield of transgenic plants.

  9. Overexpressing of OsAMT1-3, a High Affinity Ammonium Transporter Gene, Modifies Rice Growth and Carbon-Nitrogen Metabolic Status.

    Science.gov (United States)

    Bao, Aili; Liang, Zhijun; Zhao, Zhuqing; Cai, Hongmei

    2015-04-23

    AMT1-3 encodes the high affinity NH₄⁺ transporter in rice roots and is predominantly expressed under nitrogen starvation. In order to evaluate the effect of AMT1-3 gene on rice growth, nitrogen absorption and metabolism, we generated AMT1-3-overexpressing plants and analyzed the growth phenotype, yield, carbon and nitrogen metabolic status, and gene expression profiles. Although AMT1-3 mRNA accumulated in transgenic plants, these plants displayed significant decreases in growth when compared to the wild-type plants. The nitrogen uptake assay using a 15N tracer revealed poor nitrogen uptake ability in AMT1-3-overexpressing plants. We found significant decreases in AMT1-3-overexpressing plant leaf carbon and nitrogen content accompanied with a higher leaf C/N ratio. Significant changes in soluble proteins and carbohydrates were also observed in AMT1-3-overexpressing plants. In addition, metabolite profile analysis demonstrated significant changes in individual sugars, organic acids and free amino acids. Gene expression analysis revealed distinct expression patterns of genes that participate in carbon and nitrogen metabolism. Additionally, the correlation between the metabolites and gene expression patterns was consistent in AMT1-3-overexpressing plants under both low and high nitrogen growth conditions. Therefore, we hypothesized that the carbon and nitrogen metabolic imbalance caused by AMT1-3 overexpressing attributed to the poor growth and yield of transgenic plants.

  10. An integrated study of uranyl mineral dissolution processes. Etch pit formation, effects of cations in solution, and secondary precipitation

    Energy Technology Data Exchange (ETDEWEB)

    Schindler, M. [Laurentian Univ., Sudbury, ON (Canada). Dept. of Earth Sciences; Hawthorne, F.C. [Manitoba Univ., Winnipeg, MB (Canada). Dept. of Geological Sciences; Mandaliev, P. [Eidgenoessische Technische Hochschule (ETH), Zurich (Switzerland). Dept. of Environmental Sciences; Burns, P.C.; Maurice, P.A. [Notre Dame Univ., IN (United States). Dept. of Civil Engineering and Geological Sciences

    2011-07-01

    Understanding the mechanism(s) of uranium-mineral dissolution is crucial for predictive modeling of U mobility in the subsurface. In order to understand how pH and type of cation in solution may affect dissolution, experiments were performed on mainly single crystals of curite, Pb{sup 2+}{sub 3}(H{sub 2}O){sub 2}[(UO{sub 2}){sub 4}O{sub 4}(OH){sub 3}]{sub 2}, becquerelite, Ca(H{sub 2}O){sub 8}[(UO{sub 2}){sub 6}O{sub 4}(OH){sub 6}], billietite, Ba(H{sub 2}O){sub 7}[(UO{sub 2}){sub 6}O{sub 4}(OH){sub 6}], fourmarierite Pb{sup 2+}{sub 1-x}(H{sub 2}O){sub 4}[(UO{sub 2}){sub 4}O{sub 3-2x}(OH){sub 4+2x}] (x= 0.00-0.50), uranophane, Ca(H{sub 2}O){sub 5}[(UO{sub 2})(SiO{sub 3}OH)]{sub 2}, zippeite, K{sub 3}(H{sub 2}O){sub 3}[(UO{sub 2}){sub 4}(SO{sub 4}){sub 2}O{sub 3}(OH)], and Na-substituted metaschoepite, Na{sub 1-x}[(UO{sub 2}){sub 4}O{sub 2-x}(OH){sub 5+x}] (H{sub 2}O){sub n}. Solutions included: deionized water; aqueous HCl solutions at pH 3.5 and 2; 0.5 mol L{sup -1} Pb(II)-, Ba-, Sr-, Ca-, Mg-, HCl solutions at pH 2; 1.0 mol L{sup -1} Na- and K-HCl solutions at pH 2; and a 0.1 mol L{sup -1} Na{sub 2}CO{sub 3} solution at pH 10.5. Uranyl mineral basal surface microtopography, micromorphology, and composition were examined prior to, and after dissolution experiments on micrometer scale specimens using atomic force microscopy, scanning electron microscopy, and X-ray photoelectron spectroscopy. Evolution of etch pit depth at different pH values and experimental durations can be explained using a stepwave dissolution model. Effects of the cation in solution on etch pit symmetry and morphology can be explained using an adsorption model involving specific surface sites. Surface precipitation of the following phases was observed: (a) a highly-hydrated uranyl-hydroxy-hydrate in ultrapure water (on all minerals), (b) a Na-uranyl-hydroxy-hydrate in Na{sub 2}CO{sub 3} solution of pH 10.5 (on uranyl-hydroxy-hydrate minerals), (c) a Na-uranyl-carbonate on zippeite, (d) Ba- and

  11. The CCAAT box-binding factor stimulates ammonium assimilation in Saccharomyces cerevisiae, defining a new cross-pathway regulation between nitrogen and carbon metabolisms.

    OpenAIRE

    Dang, V D; Bohn, C.; Bolotin-Fukuhara, M; Daignan-Fornier, B.

    1996-01-01

    In Saccharomyces cerevisiae, carbon and nitrogen metabolisms are connected via the incorporation of ammonia into glutamate; this reaction is catalyzed by the NADP-dependent glutamate dehydrogenase (NADP-GDH) encoded by the GDH1 gene. In this report, we show that the GDH1 gene requires the CCAAT box-binding activator (HAP complex) for optimal expression. This conclusion is based on several lines of evidence: (1) overexpression of GDH1 can correct the growth defect of hap2 and hap3 mutants on a...

  12. Enhanced Adsorption and Recovery of Uranyl Ions by NikR Mutant-Displaying Yeast

    Directory of Open Access Journals (Sweden)

    Kouichi Kuroda

    2014-04-01

    Full Text Available Uranium is one of the most important metal resources, and the technology for the recovery of uranyl ions (UO22+ from aqueous solutions is required to ensure a semi-permanent supply of uranium. The NikR protein is a Ni2+-dependent transcriptional repressor of the nickel-ion uptake system in Escherichia coli, but its mutant protein (NikRm is able to selectively bind uranyl ions in the interface of the two monomers. In this study, NikRm protein with ability to adsorb uranyl ions was displayed on the cell surface of Saccharomyces cerevisiae. To perform the binding of metal ions in the interface of the two monomers, two metal-binding domains (MBDs of NikRm were tandemly fused via linker peptides and displayed on the yeast cell surface by fusion with the cell wall-anchoring domain of yeast α-agglutinin. The NikRm-MBD-displaying yeast cells with particular linker lengths showed the enhanced adsorption of uranyl ions in comparison to the control strain. By treating cells with citrate buffer (pH 4.3, the uranyl ions adsorbed on the cell surface were recovered. Our results indicate that the adsorption system by yeast cells displaying tandemly fused MBDs of NikRm is effective for simple and concentrated recovery of uranyl ions, as well as adsorption of uranyl ions.

  13. Enhanced adsorption and recovery of uranyl ions by NikR mutant-displaying yeast.

    Science.gov (United States)

    Kuroda, Kouichi; Ebisutani, Kazuki; Iida, Katsuya; Nishitani, Takashi; Ueda, Mitsuyoshi

    2014-04-11

    Uranium is one of the most important metal resources, and the technology for the recovery of uranyl ions (UO22+) from aqueous solutions is required to ensure a semi-permanent supply of uranium. The NikR protein is a Ni2+-dependent transcriptional repressor of the nickel-ion uptake system in Escherichia coli, but its mutant protein (NikRm) is able to selectively bind uranyl ions in the interface of the two monomers. In this study, NikRm protein with ability to adsorb uranyl ions was displayed on the cell surface of Saccharomyces cerevisiae. To perform the binding of metal ions in the interface of the two monomers, two metal-binding domains (MBDs) of NikRm were tandemly fused via linker peptides and displayed on the yeast cell surface by fusion with the cell wall-anchoring domain of yeast α-agglutinin. The NikRm-MBD-displaying yeast cells with particular linker lengths showed the enhanced adsorption of uranyl ions in comparison to the control strain. By treating cells with citrate buffer (pH 4.3), the uranyl ions adsorbed on the cell surface were recovered. Our results indicate that the adsorption system by yeast cells displaying tandemly fused MBDs of NikRm is effective for simple and concentrated recovery of uranyl ions, as well as adsorption of uranyl ions.

  14. Understanding the bonding nature of uranyl ion and functionalized graphene: a theoretical study.

    Science.gov (United States)

    Wu, Qun-Yan; Lan, Jian-Hui; Wang, Cong-Zhi; Xiao, Cheng-Liang; Zhao, Yu-Liang; Wei, Yue-Zhou; Chai, Zhi-Fang; Shi, Wei-Qun

    2014-03-20

    Studying the bonding nature of uranyl ion and graphene oxide (GO) is very important for understanding the mechanism of the removal of uranium from radioactive wastewater with GO-based materials. We have optimized 22 complexes between uranyl ion and GO applying density functional theory (DFT) combined with quasi-relativistic small-core pseudopotentials. The studied oxygen-containing functional groups include hydroxyl, carboxyl, amido, and dimethylformamide. It is observed that the distances between uranium atoms and oxygen atoms of GO (U-OG) are shorter in the anionic GO complexes (uranyl/GO(-/2-)) compared to the neutral GO ones (uranyl/GO). The formation of hydrogen bonds in the uranyl/GO(-/2-) complexes can enhance the binding ability of anionic GO toward uranyl ions. Furthermore, the thermodynamic calculations show that the changes of the Gibbs free energies in solution are relatively more negative for complexation reactions concerning the hydroxyl and carboxyl functionalized anionic GO complexes. Therefore, both the geometries and thermodynamic energies indicate that the binding abilities of uranyl ions toward GO modified by hydroxyl and carboxyl groups are much stronger compared to those by amido and dimethylformamide groups. This study can provide insights for designing new nanomaterials that can efficiently remove radionuclides from radioactive wastewater.

  15. Escherichia coli response to uranyl exposure at low pH and associated protein regulations.

    Directory of Open Access Journals (Sweden)

    Arbia Khemiri

    Full Text Available Better understanding of uranyl toxicity in bacteria is necessary to optimize strains for bioremediation purposes or for using bacteria as biodetectors for bioavailable uranyl. In this study, after different steps of optimization, Escherichia coli cells were exposed to uranyl at low pH to minimize uranyl precipitation and to increase its bioavailability. Bacteria were adapted to mid acidic pH before exposure to 50 or 80 µM uranyl acetate for two hours at pH≈3. To evaluate the impact of uranium, growth in these conditions were compared and the same rates of cells survival were observed in control and uranyl exposed cultures. Additionally, this impact was analyzed by two-dimensional differential gel electrophoresis proteomics to discover protein actors specifically present or accumulated in contact with uranium.Exposure to uranium resulted in differential accumulation of proteins associated with oxidative stress and in the accumulation of the NADH/quinone oxidoreductase WrbA. This FMN dependent protein performs obligate two-electron reduction of quinones, and may be involved in cells response to oxidative stress. Interestingly, this WrbA protein presents similarities with the chromate reductase from E. coli, which was shown to reduce uranyl in vitro.

  16. A 5-day method for determination of soluble silicon concentrations in nonliquid fertilizer materials using a sodium carbonate-ammonium nitrate extractant followed by visible spectroscopy with heteropoly blue analysis: single-laboratory validation.

    Science.gov (United States)

    Sebastian, Dennis; Rodrigues, Hugh; Kinsey, Charles; Korndörfer, Gaspar; Pereira, Hamilton; Buck, Guilherme; Datnoff, Lawrence; Miranda, Stephen; Provance-Bowley, Mary

    2013-01-01

    A 5-day method for determining the soluble silicon (Si) concentrations in nonliquid fertilizer products was developed using a sodium carbonate (Na2CO3)-ammonium nitrate (NH4NO3) extractant followed by visible spectroscopy with heteropoly blue analysis at 660 nm. The 5-Day Na2CO3-NH4NO3 Soluble Si Extraction Method can be applied to quantify the plant-available Si in solid fertilizer products at levels ranging from 0.2 to 8.4% Si with an LOD of 0.06%, and LOQ of 0.20%. This Si extraction method for fertilizers correlates well with plant uptake of Si (r2 = 0.96 for a range of solid fertilizers) and is applicable to solid Si fertilizer products including blended products and beneficial substances. Fertilizer materials can be processed as received using commercially available laboratory chemicals and materials at ambient laboratory temperatures. The single-laboratory validation of the 5-Day Na2CO3-NH4NO3 Soluble Si Extraction Method has been approved by The Association of American Plant Food Control Officials for testing nonliquid Si fertilizer products.

  17. Liquid-liquid extraction of cadmium(II) by TIOACl (tri-iso-octyl ammonium chloride) ionic liquid and its application to a TIOACl impregnated carbon nanotubes system

    Energy Technology Data Exchange (ETDEWEB)

    Alguacil, F. J.; Garcia-Diaz, I.; Lopez, F. A.; Rodriguez, O.

    2015-07-01

    The extraction of cadmium(II) by the ionic liquid (R{sub 3}NH{sup +}Cl{sup -}) (R: tri-iso-octyl) in Exxsol D100 from hydrochloric acid solution has been investigated. The extraction reaction is exothermic. The numerical analysis of metal distribution data suggests the formation of R{sub 3}NH{sup +}CdCl{sup -}{sub 3} - and (R{sub 3}NH{sup +}){sub 2}CdCl{sub 4}{sup 2}- species in the organic phase. The results obtained for cadmium(II) distribution have been implemented in an impregnated multi-walled carbon nanotubes system. The influence of aqueous solution stirring speed (250-2000 min{sup -}1), adsorbent dosage (0.05-0.2 g) and temperature (20 degree centigrade-60 degree centigrade) on cadmium adsorption have been investigated. (Author)

  18. Hydroxyethyl cellulose as efficient organic inhibitor of zinc-carbon battery corrosion in ammonium chloride solution: Electrochemical and surface morphology studies

    Science.gov (United States)

    Deyab, M. A.

    2015-04-01

    Hydroxyethyl cellulose (HEC) has been investigated as corrosion inhibitor for zinc-carbon battery by polarization and electrochemical impedance spectroscopy (EIS) measurements. The obtained results show that the maximum inhibition efficiency by HEC in 26% NH4Cl solution at 300 ppm and 298 K is 92.07%. Tafel polarization studies reveal that HEC acts as an efficient mixed inhibitor. The corrosion rate is suppressed by the adsorption of HEC on the zinc surface. HEC adsorption obeys the Langmuir isotherm and the thermodynamic parameters Kads and Δ Gadso have been also calculated and discussed. Both physisorption and chemisorption may occur on the zinc surface. Surface characterization investigation using Fourier transform infrared (FTIR) spectroscopy and scanning electron microscopy (SEM) is used to ascertain the nature of the protective film.

  19. Synthesis, X-ray crystallography, thermal studies, spectroscopic and electrochemistry investigations of uranyl Schiff base complexes.

    Science.gov (United States)

    Asadi, Zahra; Shorkaei, Mohammad Ranjkesh

    2013-03-15

    Some tetradentate salen type Schiff bases and their uranyl complexes were synthesized and characterized by UV-Vis, NMR, IR, TG, C.H.N. and X-ray crystallographic studies. From these investigations it is confirmed that a solvent molecule occupied the fifth position of the equatorial plane of the distorted pentagonal bipyramidal structure. Also, the kinetics of complex decomposition by using thermo gravimetric methods (TG) was studied. The thermal decomposition reactions are first order for the studied complexes. To examine the properties of uranyl complexes according to the substitutional groups, we have carried out the electrochemical studies. The electrochemical reactions of uranyl Schiff base complexes in acetonitrile were reversible.

  20. An unprecedented up-field shift in the 13C NMR spectrum of the carboxyl carbons of the lantern-type dinuclear complex TBA[Ru2(O2CCH3)4Cl2] (TBA+ = tetra(n-butyl)ammonium cation).

    Science.gov (United States)

    Hiraoka, Yuya; Ikeue, Takahisa; Sakiyama, Hiroshi; Guégan, Frédéric; Luneau, Dominique; Gillon, Béatrice; Hiromitsu, Ichiro; Yoshioka, Daisuke; Mikuriya, Masahiro; Kataoka, Yusuke; Handa, Makoto

    2015-08-14

    A large up-field shift (-763 ppm) has been observed for the carboxyl carbons of the dichlorido complex TBA[Ru(2)(O(2)CCH(3))(4)Cl(2)] (TBA(+) = tetra(n-butyl)ammonium cation) in the (13)C NMR spectrum (CD(2)Cl(2) at 25 °C). The DFT calculations showed spin delocalization from the paramagnetic Ru(2)(5+) core to the ligands, in agreement with the large up-field shift.

  1. Ammonium diphosphitoindate(III

    Directory of Open Access Journals (Sweden)

    Farida Hamchaoui

    2013-04-01

    Full Text Available The crystal structure of the title compound, NH4[In(HPO32], is built up from InIII cations (site symmetry 3m. adopting an octahedral environment and two different phosphite anions (each with site symmetry 3m. exhibiting a triangular–pyramidal geometry. Each InO6 octahedron shares its six apices with hydrogen phosphite groups. Reciprocally, each HPO3 group shares all its O atoms with three different metal cations, leading to [In(HPO32]− layers which propagate in the ab plane. The ammonium cation likewise has site symmetry 3m.. In the structure, the cations are located between the [In(HPO32]− layers of the host framework. The sheets are held together by hydrogen bonds formed between the NH4+ cations and the O atoms of the framework.

  2. Waterproofing Materials for Ammonium Nitrate

    Directory of Open Access Journals (Sweden)

    R.S. Damse

    2004-10-01

    Full Text Available This study explores the possibility of overcoming the problem of hygroscopicity of ammonium nitrate by coating the particles with selected waterproofing materials. Gravimetric analysis ofthe samples of ammonium nitrate coated with eight different waterproofing materials, vis-a-vis, uncoated ammonium nitrate, were conducted at different relative humidity and exposuretime. The results indicate that mineral jelly is the promising waterproofing material for ammonium nitrate among the materials tested, viz, calcium stearate, dioctyl phthalate, kaoline, diethylphthalate, dinitrotoluene, shelac varnish, and beeswax. Attempts were made to confirm the waterproofing ability of mineral jelly to ammonium nitrate using differential thermal analysisand x-ray diffraction patterns as an experimental tool. Suitability of mineral jelly as an additive for the gun propellant was also assessed on the basis of theoretical calculations using THERMprogram.

  3. Nonionic metal-chelating surfactants mediated solvent-free thermo-induced separation of uranyl

    Energy Technology Data Exchange (ETDEWEB)

    Larpent, Ch.; Prevost, S. [Versailles-St-Quentin Univ., Institut Lavoisier, UMR-CNRS 8180, 78 - Versailles (France); Prevost, S.; Zemb, Th.; Testard, F. [CEA Saclay, Dept. de Recherche sur l' Etat Condense, les Atomes et les Molecules (DSM/DRECAM/SCM/LIONS), 91 - Gif sur Yvette (France); Berthon, L. [CEA Valrho, Site de Marcoule, Dept. Radiochimie et Procedes (DEN/DRCP/SCPS/LCSE), 30 (France)

    2007-08-15

    Thermo-responsive metal-chelating surfactants permit the solvent-free, cloud point extraction of uranyl nitrate and afford a real molecular economy compared to conventional separation techniques. (authors)

  4. Adsorption of uranyl species on hydroxylated titanium carbide nanosheet: A first-principles study.

    Science.gov (United States)

    Zhang, Yu-Juan; Lan, Jian-Hui; Wang, Lin; Wu, Qun-Yan; Wang, Cong-Zhi; Bo, Tao; Chai, Zhi-Fang; Shi, Wei-Qun

    2016-05-05

    In this work, hydroxylated titanium carbide Ti3C2(OH)2, a representative of the two-dimensional transition metal carbides, has been predicted to be an effective adsorbent for uranyl ions in aqueous environments for the first time using density functional theory simulations. The calculations revealed that the uranyl ion can strongly bind with Ti3C2(OH)2 nanosheet in aqueous solution regardless of the presence of anionic ligands such as OH(-), Cl(-) and NO3(-). The bidentate coordination of uranyl to the surface is energetically more favorable than other adsorption configurations, and the uranyl ion prefers to bind with the deprotonated O adsorption site rather than the protonated one on the hydroxylated surface. During the adsorption process, the chemical adsorption as well as the formation of hydrogen bonds is the dominant factor.

  5. Hydrothermal syntheses and characterization of uranyl tungstates with electro-neutral structural units

    Energy Technology Data Exchange (ETDEWEB)

    Balboni, Enrica; Burns, Peter C. [Univ. of Notre Dame, IN (United States). Dept. of Civil and Enviromental Engineering and Earth Sciences; Univ. of Notre Dame, IN (United States). Dept. of Chemistry and Biochemistry

    2015-11-01

    Two uranyl tungstates, (UO{sub 2})(W{sub 2}O{sub 7})(H{sub 2}O){sub 3} (1) and (UO{sub 2}){sub 3}(W{sub 2}O{sub 8})F{sub 2}(H{sub 2}O){sub 3} (2), were synthesized under hydrothermal conditions at 220 C and were structurally, chemically, and spectroscopically characterized. 1 Crystallizes in space group Pbcm, a = 6.673(5) Aa, b = 12.601(11) Aa, c = 11.552 Aa; 2 is in C2/m, a = 13.648(1) Aa, b = 16.852(1) Aa, c = 9.832(1) Aa, β = 125.980(1) {sup circle}. In 1 the U(VI) cations are present as (UO{sub 2}){sup 2+} uranyl ions that are coordinated by five oxygen atoms to give pentagonal bipyramids. These share two edges with two tungstate octahedra and single vertices with four additional octahedra, resulting in a sheet with the iriginite-type anion topology. Only water molecules are located in the interlayer. The structural units of 2 consist of (UO{sub 2}){sup 2+} uranyl oxy-fluoride pentagonal bipyramids present as either [UO{sub 2}F{sub 2}O{sub 3}]{sup -6} or [UO{sub 2}FO{sub 4}]{sup -5}, and strongly distorted tungstate octahedra. The linkage of uranyl pentagonal bipyramids and tungstate octahedra gives a unique sheet anion topology consisting of pentagons, squares and triangles. In 2, the uranyl tungstates sheets are connected into a novel electro-neutral three-dimensional framework through dimers of uranyl pentagonal bipyramids. These dimers connecting the sheets share an edge defined by F anions. 2 is the first example of a uranyl tungstate oxy-fluoride, and 1 and 2 are rare examples of uranyl compounds containing electro-neutral structural units.

  6. Ammonium Perchlorate and Ammonium Perchlorate- Hydroxyl Terminated Polybutadiene Simulated Combustion

    Directory of Open Access Journals (Sweden)

    Rene Francisco Boschi Gonçalves

    2012-03-01

    Full Text Available The combustion simulation of ammonium perchlorate was carried out with the software Chemkin, in two steps: the burning behavior of pure ammonium perchlorate and the one of formulated ammonium perchlorate with hydroxyl terminated polybutadiene binder. In both cases, the room pressure varied in order to verify its influence in the system. The burning environment conditions were diverse. During the combustion process, the data obtained from the kinetic chemistry simulation software were compiled. The flame structure can be described by the molar fraction of the burning products and the temperature evolution from the surface of the material.

  7. Standard test methods for chemical, mass spectrometric, spectrochemical, nuclear, and radiochemical analysis of nuclear-grade uranyl nitrate solutions

    CERN Document Server

    American Society for Testing and Materials. Philadelphia

    1999-01-01

    1.1 These test methods cover procedures for the chemical, mass spectrometric, spectrochemical, nuclear, and radiochemical analysis of nuclear-grade uranyl nitrate solution to determine compliance with specifications. 1.2 The analytical procedures appear in the following order: Sections Determination of Uranium 7 Specific Gravity by Pycnometry 15-20 Free Acid by Oxalate Complexation 21-27 Determination of Thorium 28 Determination of Chromium 29 Determination of Molybdenum 30 Halogens Separation by Steam Distillation 31-35 Fluoride by Specific Ion Electrode 36-42 Halogen Distillate Analysis: Chloride, Bromide, and Iodide by Amperometric Microtitrimetry 43 Determination of Chloride and Bromide 44 Determination of Sulfur by X-Ray Fluorescence 45 Sulfate Sulfur by (Photometric) Turbidimetry 46 Phosphorus by the Molybdenum Blue (Photometric) Method 54-61 Silicon by the Molybdenum Blue (Photometric) Method 62-69 Carbon by Persulfate Oxidation-Acid Titrimetry 70 Conversion to U3O8 71-74 Boron by ...

  8. Chemical, mass spectrometric, spectrochemical, nuclear, and radiochemical analysis of nuclear-grade uranyl nitrate solutions

    Energy Technology Data Exchange (ETDEWEB)

    1981-01-01

    The standard covers analytical procedures to determine compliance of nuclear-grade uranyl nitrate solution to specifications. The following methods are described in detail: uranium by ferrous sulfate reduction-potassium dichromate titrimetry and by ignition gravimetry; specific gravity by pycnometry; free acid by oxalate complexation; thorium by the Arsenazo(III) (photometric) method; chromium by the diphenylcarbazide (photometric) method; molybdenum by the thiocyanate (photometric) method; halogens separation by steam distillation; fluorine by specific ion electrode; halogen distillate analysis: chloride, bromide and iodide by amperometric microtitrimetry; bromine by the fluorescein (photometric) method; sulfate sulfur by (photometric) turbidimetry; phosphorus by the molybdenum blue (photometric) method; silicon by the molybdenum blue (photometric) method; carbon by persulfate oxidation-acid titrimetry; nonvolatile impurities by spectrography; volatile impurities by rotating-disk spark spectrography; boron by emission spectrography; impurity elements by spark source mass spectrography; isotopic composition by multiple filament surface-ionization mass spectrometry; uranium-232 by alpha spectrometry; total alpha activity by direct alpha counting; fission product activity by beta and gamma counting; entrained organic matter by infrared spectrophotometry. (JMT)

  9. Solubilities of carbon dioxide and oxygen in the ionic liquids methyl trioctyl ammonium bis(trifluoromethylsulfonyl)imide, 1-butyl-3-methyl imidazolium bis(trifluoromethylsulfonyl)imide, and 1-butyl-3-methyl imidazolium methyl sulfate.

    Science.gov (United States)

    Bahadur, Indra; Osman, Khalid; Coquelet, Christophe; Naidoo, Paramespri; Ramjugernath, Deresh

    2015-01-29

    Ionic liquids (ILs) are being considered as solvents for gas absorption processes as they have the potential, in general, for improved efficiency of gas separations, as well as lower capital and operating costs compared to current commercial processes. In this study the solvent properties of ILs are investigated for use in the absorption of carbon dioxide (CO2) and oxygen (O2). The absorption of these gases in ILs was measured in the temperature range 303.15-333.15 K and at pressures up to 1.5 MPa by gravimetric analysis. The ILs used were methyl trioctyl ammonium bis (trifluoromethylsulfonyl) imide ([MOA][Tf2N]), 1-butyl-3-methyl imidazolium bis (trifluoromethylsulfonyl) imide ([BMIM][Tf2N]), and 1-butyl-3-methyl imidazolium methyl sulfate ([BMIM][MeSO4]). The measurement technique employed in this study is fast and accurate, and requires small quantities of solvent. The results indicated that absorption of both gases increased with a decrease in operating temperature and an increase in pressure. [MOA][Tf2N] had the highest CO2 and O2 solubility. [BMIM][Tf2N] was determined to have the highest selectivity for CO2 absorption. [BMIM][MeSO4] achieved the lowest CO2 absorption with a moderate O2 absorption, revealing this IL to be the least desirable for CO2 and O2 absorption. Calculation of Henry's law constants for all systems confirmed the deductions made from absorption data analysis. Calculation of enthalpy and entropy of absorption for each system revealed CO2 absorption in [MOA][Tf2N] to be the least sensitive to temperature increases. The absorption data was modeled using the generic Redlich-Kwong cubic equation of state (RK-EOS) coupled with a group contribution method.

  10. Control of oxo-group functionalization and reduction of the uranyl ion.

    Science.gov (United States)

    Arnold, Polly L; Pécharman, Anne-Frédérique; Lord, Rianne M; Jones, Guy M; Hollis, Emmalina; Nichol, Gary S; Maron, Laurent; Fang, Jian; Davin, Thomas; Love, Jason B

    2015-04-01

    Uranyl complexes of a large, compartmental N8-macrocycle adopt a rigid, "Pacman" geometry that stabilizes the U(V) oxidation state and promotes chemistry at a single uranyl oxo-group. We present here new and straightforward routes to singly reduced and oxo-silylated uranyl Pacman complexes and propose mechanisms that account for the product formation, and the byproduct distributions that are formed using alternative reagents. Uranyl(VI) Pacman complexes in which one oxo-group is functionalized by a single metal cation are activated toward single-electron reduction. As such, the addition of a second equivalent of a Lewis acidic metal complex such as MgN″2 (N″ = N(SiMe3)2) forms a uranyl(V) complex in which both oxo-groups are Mg functionalized as a result of Mg-N bond homolysis. In contrast, reactions with the less Lewis acidic complex [Zn(N″)Cl] favor the formation of weaker U-O-Zn dative interactions, leading to reductive silylation of the uranyl oxo-group in preference to metalation. Spectroscopic, crystallographic, and computational analysis of these reactions and of oxo-metalated products isolated by other routes have allowed us to propose mechanisms that account for pathways to metalation or silylation of the exo-oxo-group.

  11. Temperature and pH driven association in uranyl aqueous solutions

    Directory of Open Access Journals (Sweden)

    M. Druchok

    2012-12-01

    Full Text Available An association behavior of uranyl ions in aqueous solutions is explored. For this purpose a set of all-atom molecular dynamics simulations is performed. During the simulation, the fractions of uranyl ions involved in dimer and trimer formations were monitored. To accompany the fraction statistics one also collected distributions characterizing average times of the dimer and trimer associates. Two factors effecting the uranyl association were considered: temperature and pH. As one can expect, an increase of the temperature decreases an uranyl capability of forming the associates, thus lowering bound fractions/times and vice versa. The effect of pH was modeled by adding H+ or OH- ions to a "neutral" solution. The addition of hydroxide ions OH- favors the formation of the associates, thus increasing bound times and fractions. The extra H+ ions in a solution produce an opposite effect, thus lowering the uranyl association capability. We also made a structural analysis for all the observed associates to reveal the mutual orientation of the uranyl ions.

  12. Characterization of the Aqueous Uranyl-Silicate Complex Using X-Ray Absorption Spectroscopy and Ab Initio Modeling

    Science.gov (United States)

    Vu, M.; Massey, M.; Huang, P.

    2015-12-01

    The speciation of aqueous uranium ions is an important factor in predicting its mobility and fate in the environment. Two major controls on speciation are pH and the presence of complexing ligands. For the case of aqueous uranyl, UO22+(aq), some common complexes include uranyl-hydroxy, uranyl-carbonato, and uranyl-calcium-carbonato complexes, all of which differ in chemical reactivity and mobility. Uranyl-silicate complexes are also known but remain poorly characterized. In this work, we studied uranyl speciation in a series of aqueous solutions of 0.1 mM uranyl and 2 mM silicate with pH ranging from 4 to 7. Extended X-Ray Absorption Fine Structure (EXAFS) spectra of these samples were recorded at the Stanford Synchrotron Radiation Lightsource (SLAC National Accelerator Laboratory). Of particular note are the uranyl and silicate concentrations employed in our experiments, which are lower than conditions in previously reported EXAFS studies and approach conditions in natural groundwater systems. Preliminary analyses of EXAFS data indicate that uranyl speciation changes across the pH range, consistent with published thermodynamic data that suggest uranyl-silicate complexes may be important for pH ~ 5 and below, while uranyl-carbonato complexes become dominant at circumneutral pH. To guide the interpretation of the EXAFS data, molecular-scale simulations were carried out using density functional theory. We considered two classes of models: (i) hydrated clusters, and (ii) ab initio molecular dynamics simulations of 3D-periodic models involving uranyl and silicate in water. These calculations reveal that at pH ~ 5, the uranyl speciation is the [UO2(H2O)4H3SiO4]+ complex formed by the substitution of an equatorial uranyl water with a monodentate silicate ligand. The evidence from experiments and simulations provide a consistent picture for the uranyl-silicate complex, which may be important in the transport of uranyl in acidic, silicate-rich waters.

  13. Biocidal quaternary ammonium resin

    Science.gov (United States)

    Janauer, G. E.

    1983-01-01

    Activated carbon (charcoal) and polymeric resin sorbents are widely used in the filtration and treatment of drinking water, mainly to remove dissolved organic and inorganic impurities and to improve the taste. Earlier hopes that activated carbon might "disinfect' water proved to be unfounded. The feasibility of protecting against microbial infestation in charcoal and resin beds such as those to be incorporated into total water reuse systems in spacecraft was investigated. The biocidal effect of IPCD (insoluable polymeric contact disinfectants) in combination with a representative charcoal was assessed. The ion exchange resins (IPCD) were shown to adequately protect charcoal and ion exchange beds.

  14. Highly efficient hydrogen storage system based on ammonium bicarbonate/formate redox equilibrium over palladium nanocatalysts.

    Science.gov (United States)

    Su, Ji; Yang, Lisha; Lu, Mi; Lin, Hongfei

    2015-03-01

    A highly efficient, reversible hydrogen storage-evolution process has been developed based on the ammonium bicarbonate/formate redox equilibrium over the same carbon-supported palladium nanocatalyst. This heterogeneously catalyzed hydrogen storage system is comparable to the counterpart homogeneous systems and has shown fast reaction kinetics of both the hydrogenation of ammonium bicarbonate and the dehydrogenation of ammonium formate under mild operating conditions. By adjusting temperature and pressure, the extent of hydrogen storage and evolution can be well controlled in the same catalytic system. Moreover, the hydrogen storage system based on aqueous-phase ammonium formate is advantageous owing to its high volumetric energy density.

  15. Alkali-metal ion coordination in uranyl(VI) poly-peroxide complexes in solution. Part 1: the Li⁺, Na⁺ and K⁺--peroxide-hydroxide systems.

    Science.gov (United States)

    Zanonato, Pier Luigi; Di Bernardo, Plinio; Vallet, Valerie; Szabó, Zoltán; Grenthe, Ingmar

    2015-01-28

    The alkali metal ions Li(+), Na(+) and K(+) have a profound influence on the stoichiometry of the complexes formed in uranyl(VI)-peroxide-hydroxide systems, presumably as a result of a templating effect, resulting in the formation of two complexes, M[(UO2)(O2)(OH)]2(-) where the uranyl units are linked by one peroxide bridge, μ-η(2)-η(2), with the second peroxide coordinated "end-on", η(2), to one of the uranyl groups, and M[(UO2)(O2)(OH)]4(3-), with a four-membered ring of uranyl ions linked by μ-η(2)-η(2) peroxide bridges. The stoichiometry and equilibrium constants for the reactions: M(+) + 2UO2(2+) + 2HO2(-) + 2H2O → M[(UO2)(O2)(OH)]2(-) + 4H(+) (1) and M(+) + 4UO2(2+) + 4HO2(-) + 4H2O → M[(UO2)(O2)(OH)]4(3-) + 8H(+) (2) have been measured at 25 °C in 0.10 M (tetramethyl ammonium/M(+))NO3 ionic media using reaction calorimetry. Both reactions are strongly enthalpy driven with large negative entropies of reaction; the observation that ΔH(2) ≈ 2ΔH(1) suggests that the enthalpy of reaction is approximately the same when peroxide is added in bridging and "end-on" positions. The thermodynamic driving force in the reactions is the formation of strong peroxide bridges and the role of M(+) cations is to provide a pathway with a low activation barrier between the reactants and in this way "guide" them to form peroxide bridged complexes; they play a similar role as in the synthesis of crown-ethers. Quantum chemical (QC) methods were used to determine the structure of the complexes, and to demonstrate how the size of the M(+)-ions affects their coordination geometry. There are several isomers of Na[(UO2)(O2)(OH)]2(-) and QC energy calculations show that the ones with a peroxide bridge are substantially more stable than the ones with hydroxide bridges. There are isomers with different coordination sites for Na(+) and the one with coordination to the peroxide bridge and two uranyl oxygen atoms is the most stable one.

  16. 21 CFR 184.1138 - Ammonium chloride.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 3 2010-04-01 2009-04-01 true Ammonium chloride. 184.1138 Section 184.1138 Food... Specific Substances Affirmed as GRAS § 184.1138 Ammonium chloride. (a) Ammonium chloride (NH4Cl, CAS Reg. No. 12125-02-9) is produced by the reaction of sodium chloride and an ammonium salt in solution....

  17. 21 CFR 184.1133 - Ammonium alginate.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 3 2010-04-01 2009-04-01 true Ammonium alginate. 184.1133 Section 184.1133 Food... Specific Substances Affirmed as GRAS § 184.1133 Ammonium alginate. (a) Ammonium alginate (CAS Reg. No. 9005.... Ammonium alginate is prepared by the neutralization of purified alginic acid with appropriate pH...

  18. Temperature and pH driven association in uranyl aqueous solutions

    CERN Document Server

    Druchok, M; 10.5488/CMP.15.43602

    2013-01-01

    An association behavior of uranyl ions in aqueous solutions is explored. For this purpose a set of all-atom molecular dynamics simulations is performed. During the simulation, the fractions of uranyl ions involved in dimer and trimer formations were monitored. To accompany the fraction statistics one also collected distributions characterizing average times of the dimer and trimer associates. Two factors effecting the uranyl association were considered: temperature and pH. As one can expect, an increase of the temperature decreases an uranyl capability of forming the associates, thus lowering bound fractions/times and vice versa. The effect of pH was modeled by adding H^+ or OH^- ions to a "neutral" solution. The addition of hydroxide ions OH^- favors the formation of the associates, thus increasing bound times and fractions. The extra H^+ ions in a solution produce an opposite effect, thus lowering the uranyl association capability. We also made a structural analysis for all the observed associates to reveal...

  19. Status Update: Uranyl Nitrate Calibration Loop Equipment (UNCLE) at ORNL

    Energy Technology Data Exchange (ETDEWEB)

    Ladd-Lively, Jennifer L [ORNL

    2009-01-01

    The successful completion of a field trial of safeguards monitoring equipment at a natural uranium conversion plant (NUCP) demonstrated the need for a facility in which to perform full-scale equipment testing under controlled conditions prior to field deployment of safeguards systems at additional plants. Oak Ridge National Laboratory has developed a Uranyl Nitrate Calibration Loop Equipment (UNCLE) facility to simulate the full-scale operating conditions for a purified uranium-bearing aqueous stream exiting the solvent extraction process conducted in an NUCP. In addition to calibrating instruments such as the neutron detector developed at Los Alamos National Laboratory, UNCLE will be used to test other in-line instruments (mass and volumetric flowmeters, spectrophotometers, etc.). UNCLE will be able to test commercially available equipment, such as the Endress+Hauser Promass 83F Coriolis meter that was used in the field test and other equipment that is presently under development. UNCLE is designed to accommodate different pipe sizes, flow rates, solution concentrations, and other variables of interest. Construction is expected to be completed by the end of September 2008 with initial testing beginning later that year. The design and current status of UNCLE will be presented, along with the capabilities of the facility and the proposed test plans.

  20. Ultrastructural and metabolic changes in osteoblasts exposed to uranyl nitrate

    Energy Technology Data Exchange (ETDEWEB)

    Tasat, D.R. [Universidad Nacional de San Martin, Escuela de Ciencia y Tecnologia, Pcia de Bs.As. (Argentina); Universidad de Buenos Aires, Catedra de Histologia y Embriologia, Facultad de Odontologia, Buenos Aires (Argentina); Orona, N.S. [Universidad Nacional de San Martin, Escuela de Ciencia y Tecnologia, Pcia de Bs.As. (Argentina); Mandalunis, P.M. [Universidad de Buenos Aires, Catedra de Histologia y Embriologia, Facultad de Odontologia, Buenos Aires (Argentina); Cabrini, R.L. [Comision Nacional de Energia Atomica, Departamento de Radiobiologia, Buenos Aires (Argentina); Ubios, A.M. [Comision Nacional de Energia Atomica, Departamento de Radiobiologia, Buenos Aires (Argentina); Universidad de Buenos Aires, Catedra de Histologia y Embriologia, Facultad de Odontologia, Buenos Aires (Argentina)

    2007-05-15

    Exposure to uranium is an occupational hazard to workers who continually handle uranium and an environmental risk to the population at large. Since the cellular and molecular pathways of uranium toxicity in osteoblast cells are still unknown, the aim of the present work was to evaluate the adverse effects of uranyl nitrate (UN) on osteoblasts both in vivo and in vitro. Herein we studied the osteoblastic ultrastructural changes induced by UN in vivo and analyzed cell proliferation, generation of reactive oxygen species (ROS), apoptosis, and alkaline phosphatase (APh) activity in osteoblasts exposed to various UN concentrations (0.1, 1, 10, and 100 {mu}M) in vitro. Cell proliferation was quantified by means of the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay, ROS was determined using the nitro blue tetrazolium test, apoptosis was morphologically determined using Hoechst 3332 and APh activity was assayed spectrophotometrically. Electron microscopy revealed that the ultrastructure of active and inactive osteoblasts exposed to uranium presented cytoplasmic and nuclear alterations. In vitro, 1-100 {mu}M UN failed to modify cell proliferation ratio and to induce apoptosis. ROS generation increased in a dose-dependent manner in all tested doses. APh activity was found to decrease in 1-100 {mu}M UN-treated cells vs. controls. Our results show that UN modifies osteoblast cell metabolism by increasing ROS generation and reducing APh activity, suggesting that ROS may play a more complex role in cell physiology than simply causing oxidative damage. (orig.)

  1. Dehydration of Uranyl Nitrate Hexahydrate to Uranyl Nitrate Trihydrate under Ambient Conditions as Observed via Dynamic Infrared Reflectance Spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Johnson, Timothy J.; Sweet, Lucas E.; Meier, David E.; Mausolf, Edward J.; Kim, Eunja; Weck, Philippe F.; Buck, Edgar C.; McNamara, Bruce K.

    2015-05-22

    the hexahydrate [UO2(NO3)2(H2O)6] (UNH) and the trihydrate [UO2(NO3)2(H2O)3] (UNT) forms. Their stabilities depend on both relative humidity and temperature. Both phases have previously been studied by infrared transmission spectroscopy, but the data were limited by both instrumental resolution and the ability to prepare the samples as pellets without desiccating them. We report time-resolved infrared (IR) measurements using an integrating sphere that allow us to observe the transformation from the hexahydrate to the trihydrate simply by flowing dry nitrogen gas over the sample. Hexahydrate samples were prepared and confirmed via known XRD patterns, then measured in reflectance mode. The hexahydrate has a distinct uranyl asymmetric stretch band at 949.0 cm-1 that shifts to shorter wavelengths and broadens as the sample dehydrates and recrystallizes to the trihydrate, first as a blue edge shoulder but ultimately resulting in a doublet band with reflectance peaks at 966 and 957 cm-1. The data are consistent with transformation from UNH to UNT since UNT has two non-equivalent UO22+ sites. The dehydration of UO2(NO3)2(H2O)6 to UO2(NO3)2(H2O)3 is both a morphological and structural change that has the lustrous lime green crystals changing to the dull greenish yellow of the trihydrate. Crystal structures and phase transformation were confirmed theoretically using DFT calculations and experimentally via microscopy methods. Both methods showed a transformation with two distinct sites for the uranyl cation in the trihydrate, as opposed to a single crystallographic site in the hexahydrate.

  2. Pulmonary effects of ultrafine and fine ammonium salts aerosols in healthy and monocrotaline-treated rats following short-term exposure

    NARCIS (Netherlands)

    Cassee, F.R.; Arts, J.H.E.; Fokkens, P.H.B.; Spoor, S.M.; Boere, A.J.F.; Bree, L. van; Dormans, J.A.M.A.

    2002-01-01

    In the present study the effects of a 3-day inhalation exposure to model compounds for ambient particulate matter were investigated: ammonium bisulfate, ammonium ferrosulfate, and ammonium nitrate, all components of the secondary aerosol fraction of ambient particulate matter (PM), and carbon black

  3. 碳酸钙-氯化铵烧结法测定真空炼锂炉渣中锂的含量%Determination of Lithium in Slag Refined by Vacuum with Calcium Carbonate and Ammonium Chloride Agglomeration

    Institute of Scientific and Technical Information of China (English)

    李秋霞; 杨猛

    2001-01-01

    研究了利用碳酸钙-氯化铵烧结法测定金属锂真空精炼后炉渣中锂的含量。%Determination of lithium in slag refined by vacuum with calciumcarbonate and ammonium chloride agglomeration was reported.

  4. Synthesis, spectroscopy, and thermal study of uranyl unsymmetrical Schiff base complexes.

    Science.gov (United States)

    Kianfar, Ali Hossein; Dostani, Morteza

    2011-11-01

    The new uranyl complexes with tetradentate unsymmetrical N(2)O(2) Schiff base ligands were synthesized and characterized by IR, UV-vis, NMR and elemental analysis. The DMF solvent is coordinated to uranyl complexes. The thermogravimetry (TG) and differential thermoanalysis (DTA) of the uranyl complexes were carried out in the range of 20-700°C. The UO(2)L(1) complex was decomposed in two and the others were decomposed in three stages. Up to 100°C, the coordinated solvent was released then the Schiff base ligands were decomposed in one or two steps. Decomposition of synthesized complexes is related to the Schiff base characteristics. The thermal decomposition reaction is first order for the studied complexes.

  5. Crystal structure of new uranyl oxalates (NH{sub 4}){sub 2}[UO{sub 2}(C{sub 2}O{sub 4}){sub 2}.H{sub 2}O].2H{sub 2}O and (NH{sub 4}){sub 2-x}(N{sub 2}H{sub 5}){sub x}[(UO{sub 2}){sub 2}(C{sub 2}O{sub 4}){sub 3}].3H{sub 2}O (x = 0 and x = 1). Comparison with other uranyl oxalates

    Energy Technology Data Exchange (ETDEWEB)

    Chapelet-Arab, B. [Lab. de Cristallochimie et Physicochimie du Solide, UMR CNRS, Villeneuve d' Ascq (France); Lab. de Chimie des Actinides, CEA VALRHO/DRCP/SCPS, Bagnols sur Ceze (France); Nowogrocki, G.; Abraham, F. [Lab. de Cristallochimie et Physicochimie du Solide, UMR CNRS, Villeneuve d' Ascq (France); Grandjean, S. [Lab. de Chimie des Actinides, CEA VALRHO/DRCP/SCPS, Bagnols sur Ceze (France)

    2005-07-01

    Two new ammonium uranyl oxalates (NH{sub 4}){sub 2}[UO{sub 2}(C{sub 2}O{sub 4}){sub 2}H{sub 2}O].2H{sub 2}O (1) and (NH{sub 4}){sub 2}[(UO{sub 2}){sub 2}(C{sub 2}O{sub 4}){sub 3}].3H{sub 2}O (2) and one mixed ammonium hydrazinium uranyl oxalate (NH{sub 4})(N{sub 2}H{sub 5})[(UO{sub 2}){sub 2}(C{sub 2}O{sub 4}){sub 3}].3H{sub 2}O (3) have been prepared. The crystal structures of the three compounds have been determined by single-crystal X-ray diffraction. The crystal structures were solved by the Patterson method and Fourier difference techniques, and refined by a least square method on the basis of F{sup 2} for all unique reflections. Crystallographic data: 1, hexagonal, space group P6{sub 1}22, a = 8.143(2) Aa, c = 36.179(18) Aa, Z = 6, R1 = 0.0268 for 105 parameters with 1223 reflections with I {>=} 2{sigma}(I); 2, monoclinic, space group P2{sub 1}/n, a = 8.705(3) Aa, b = 19.454(6) Aa, c = 5.5105(18) Aa, {beta} = 101.741(5) , Z = 2, R1 = 0.0314 for 139 parameters with 2059 reflections with I {>=} 2{sigma}(I); 3, monoclinic, space group P2{sub 1}/n, a = 8.958(3) Aa, b = 19.601(7) Aa, c = 11.007(4) Aa, {beta} = 112.928(5) , Z = 4, R1 = 0.0363 for 131 parameters with 3346 reflections with I {>=} 2{sigma}(I). The crystal structure of 1 contains [UO{sub 2}(C{sub 2}O{sub 4}){sub 2}.H{sub 2}O]{sup 2-} anions, NH{sub 4}{sup +} cations and water molecules. In the anion, the linear uranyl group is coordinated by two bidentate oxalate anions and one water molecule giving a pentagonal bipyramidal environment for the uranium atom. The structures of 2 and 3 consist of two-dimensional networks built from uranyl and oxalate ions forming hexagonal rings. The oxalate ions are tetradentate, each bridging two uranyl ions which are coordinated by three oxalate groups to give distorted hexagonal bipyramidal environments for the uranium atoms. In 3, the ammonium and hydrazinium ions are ordered in successive layers. The various possible coordinations for the uranyl cation and the great

  6. Selectivity in ligand binding to uranyl compounds: A synthetic, structural, thermodynamic and computational study

    Energy Technology Data Exchange (ETDEWEB)

    Arnold, John [Univ. of California, Berkeley, CA (United States)

    2015-01-21

    The uranyl cation (UO₂²⁺) is the most abundant form of uranium on the planet. It is estimated that 4.5 billion tons of uranium in this form exist in sea water. The ability to bind and extract the uranyl cation from aqueous solution while separating it from other elements would provide a limitless source of nuclear fuel. A large body of research concerns the selective recognition and extraction of uranyl. A stable molecule, the cation has a linear O=U=O geometry. The short U-O bonds (1.78 Å) arise from the combination of uranium 5f/6d and oxygen 2p orbitals. Due to the oxygen moieties being multiply bonded, these sites were not thought to be basic enough for Lewis acidic coordination to be a viable approach to sequestration. The goal of this research is thus to broaden the coordination chemistry of the uranyl ion by studying new ligand systems via synthetic, structural, thermodynamic and computational methods. It is anticipated that this fundamental science will find use beyond actinide separation technologies in areas such as nuclear waste remediation and nuclear materials. The focus of this study is to synthesize uranyl complexes incorporating amidinate and guanidinate ligands. Both synthetic and computational methods are used to investigate novel equatorial ligand coordination and how this affects the basicity of the oxo ligands. Such an understanding will later apply to designing ligands incorporating functionalities that can bind uranyl both equatorially and axially for highly selective sequestration. Efficient and durable chromatography supports for lanthanide separation will be generated by (1) identifying robust peptoid-based ligands capable of binding different lanthanides with variable affinities, and (2) developing practical synthetic methods for the attachment of these ligands to Dowex ion exchange resins.

  7. Removal of uranyl ions by p-hexasulfonated calyx[6]arene acid

    Science.gov (United States)

    Popescu (Hoştuc), Ioana-Carmen; Petru, Filip; Humelnicu, Ionel; Mateescu, Marina; Militaru, Ecaterina; Humelnicu, Doina

    2014-10-01

    Radioactive pollution is a significant threat for the people’s health. Therefore highly effective radioactive decontamination methods are required. Ion exchange, biotechnologies and phytoremediation in constructed wetlands have been used as radioactive decontamination technologies for uranium contaminated soil and water remediation. Recently, beside those classical methods the calix[n]arenic derivatives’ utilization as radioactive decontaminators has jogged attention. The present work aims to present the preliminary research results of uranyl ion sorption studies on the p-hexasulfonated calyx[6]arenic acid. The effect of temperature, contact time, sorbent amount and uranyl concentration variation on sorption efficiency was investigated. Isotherm models revealed that the sorption process fit better Langmuir isotherm.

  8. Removal of uranyl ions by p-hexasulfonated calyx[6]arene acid

    Energy Technology Data Exchange (ETDEWEB)

    Popescu, Ioana-Carmen [R and D National Institute for Metals and Radioactive Resources–ICPMRR, B-dul Carol I No.70, Sector 2, Bucharest 020917 (Romania); Petru, Filip [“C.D. Nenitescu” Institute of Organic Chemistry, Splaiul Independentei 202B, Sector 6, Bucharest 71141 (Romania); Humelnicu, Ionel [“Al.I. Cuza” University of Iasi, The Faculty of Chemistry, Bd. Carol-I No. 11, Iasi 700506 (Romania); Mateescu, Marina [National R and D Institute for Chemistry and Petrochemistry, Splaiul Independenţei No. 202, Bucharest 060021 (Romania); Militaru, Ecaterina [R and D National Institute for Metals and Radioactive Resources–ICPMRR, B-dul Carol I No.70, Sector 2, Bucharest 020917 (Romania); Humelnicu, Doina, E-mail: doinah@uaic.ro [“Al.I. Cuza” University of Iasi, The Faculty of Chemistry, Bd. Carol-I No. 11, Iasi 700506 (Romania)

    2014-10-15

    Radioactive pollution is a significant threat for the people’s health. Therefore highly effective radioactive decontamination methods are required. Ion exchange, biotechnologies and phytoremediation in constructed wetlands have been used as radioactive decontamination technologies for uranium contaminated soil and water remediation. Recently, beside those classical methods the calix[n]arenic derivatives’ utilization as radioactive decontaminators has jogged attention. The present work aims to present the preliminary research results of uranyl ion sorption studies on the p-hexasulfonated calyx[6]arenic acid. The effect of temperature, contact time, sorbent amount and uranyl concentration variation on sorption efficiency was investigated. Isotherm models revealed that the sorption process fit better Langmuir isotherm.

  9. Study of the extraction mechanisms by TBP saturated by uranyl nitrate; Etude des mecanismes d'extraction du TBP sature par le nitrate d'uranyle

    Energy Technology Data Exchange (ETDEWEB)

    Meze, F

    2004-02-15

    This work deals with a particular phenomenon likely to occur in the nuclear waste reprocessing process PUREX. It was shown earlier by Russian works that the extractant molecule, tributyl phosphate (TBP), saturated by uranyl nitrate keeps its extraction capacities for nitric acid and tetravalent actinides. This study is composed of three parts. Firstly, some liquid-liquid extraction experiments were conducted to verify the ability of TBP saturated by uranyl nitrate to conserve its extraction capacities for nitric acid. Then, during these experiments, the UV and infrared spectra of both phases were recorded to obtain the organic phase speciation. At last, the informations gathered during the experimental part were used to build a general species distribution model of the H{sub 2}O/HNO{sub 3}/UO{sub 2}(NO{sub 3}){sub 2}/TBP system. (author)

  10. Standard test method for isotopic analysis of hydrolyzed uranium hexafluoride and uranyl nitrate solutions by thermal ionization mass spectrometry

    CERN Document Server

    American Society for Testing and Materials. Philadelphia

    2005-01-01

    1.1 This method applies to the determination of isotopic composition in hydrolyzed nuclear grade uranium hexafluoride. It covers isotopic abundance of 235U between 0.1 and 5.0 % mass fraction, abundance of 234U between 0.0055 and 0.05 % mass fraction, and abundance of 236U between 0.0003 and 0.5 % mass fraction. This test method may be applicable to other isotopic abundance providing that corresponding standards are available. 1.2 This test method can apply to uranyl nitrate solutions. This can be achieved either by transforming the uranyl nitrate solution to a uranyl fluoride solution prior to the deposition on the filaments or directly by depositing the uranyl nitrate solution on the filaments. In the latter case, a calibration with uranyl nitrate standards must be performed. 1.3 This test method can also apply to other nuclear grade matrices (for example, uranium oxides) by providing a chemical transformation to uranyl fluoride or uranyl nitrate solution. 1.4 This standard does not purport to address al...

  11. 21 CFR 582.1141 - Ammonium phosphate.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 6 2010-04-01 2010-04-01 false Ammonium phosphate. 582.1141 Section 582.1141 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) ANIMAL... Additives § 582.1141 Ammonium phosphate. (a) Product. Ammonium phosphate (mono- and dibasic). (b)...

  12. 76 FR 46907 - Ammonium Nitrate Security Program

    Science.gov (United States)

    2011-08-03

    ... and fertilizer blends containing more than 15% by weight ammonium nitrate, except liquid fertilizers... concerning the detonability of ammonium nitrate; Comments on how likely ammonium nitrate fertilizer users would be to use an alternative fertilizer that is potentially less detonable, such as Sulf-N...

  13. 76 FR 11273 - Ammonium Nitrate From Russia

    Science.gov (United States)

    2011-03-01

    ... COMMISSION Ammonium Nitrate From Russia AGENCY: United States International Trade Commission. ACTION: Institution of a five-year review concerning the suspended investigation on ammonium nitrate from Russia... investigation on ammonium nitrate from Russia would be likely to lead to continuation or recurrence of...

  14. 76 FR 47238 - Ammonium Nitrate From Russia

    Science.gov (United States)

    2011-08-04

    ... COMMISSION Ammonium Nitrate From Russia Determination On the basis of the record \\1\\ developed in the subject... order on ammonium nitrate from Russia would be likely to lead to continuation or recurrence of material... Commission are contained in USITC Publication 4249 (August 2011), entitled Ammonium Nitrate from...

  15. 21 CFR 582.7133 - Ammonium alginate.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 6 2010-04-01 2010-04-01 false Ammonium alginate. 582.7133 Section 582.7133 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) ANIMAL... Ammonium alginate. (a) Product. Ammonium alginate. (b) Conditions of use. This substance is...

  16. On the retention of uranyl and thorium ions from radioactive solution on peat moss.

    Science.gov (United States)

    Humelnicu, Doina; Bulgariu, Laura; Macoveanu, Matei

    2010-02-15

    The efficiency of the radioactive uranyl and thorium ions on the peat moss from aqueous solutions has been investigated under different experimental conditions. The sorption and desorption of uranyl and thorium ions on three types (unmodified peat moss, peat moss treated with HNO(3) and peat moss treated with NaOH) of peat moss were studied by the static method. Peat moss was selected as it is available in nature, in any amount, as a cheap and accessible sorbent. Study on desorption of such ions led to the conclusion that the most favourable desorptive reagent for the uranyl ions is Na(2)CO(3) 1M while, for the thorium ions is HCl 1M. The results obtained show that the parameters here under investigation exercise a significant effect on the sorption process of the two ions. Also, the investigations performed recommend the peat moss treated with a base as a potential sorbent for the uranyl and thorium ions from a radioactive aqueous solution.

  17. On the bonding and the electric field gradient of the uranyl ion

    NARCIS (Netherlands)

    de Jong, WA; Visscher, L; Nieuwpoort, WC

    1999-01-01

    Molecular properties of the uranyl ion ([UO2](2+)) are studied using both a non-relativistic and a relativistic method. Inclusion of relativity leads to a bond length expansion and makes the electric field gradient (EFG) at the uranium nucleus strongly dependent on the U-O bond distance, The non-rel

  18. Removal of uranyl ions from residual waters using some algae types

    NARCIS (Netherlands)

    Cecal, A; Palamaru, [No Value; Humelnicu, D; Popa, K; Salaru, VV; Rudic, [No Value; Gulea, A

    1999-01-01

    This paper deals with a study on the bioaccumulation of uranyl ions resulted from residual effluents by means of some microbiological collectors: Scenedesmus quadricauda, Anabaena karakumica, Calothrix brevissima, Penicillinium sp, as well as the Glucide extract of Porphyridium cruentum, under vario

  19. Nucleobase assemblies supported by uranyl cation coordination and other non-covalent interactions

    Indian Academy of Sciences (India)

    Jitendra Kumar; Sandeep Verma

    2011-11-01

    We describe synthesis and solid state structural description of uranyl complexes of carboxylate functionalized adenine and uracil derivatives. The metal coordination through carboxylate pendant leads to the formation of dimeric assemblies, whereas the directional nature of hydrogen bonding interaction supported by nucleobases and aqua ligands, result in the generation of complex 3-D architectures containing embedded nucleobase ribbons.

  20. Extraction of uranyl nitrate, sulphate and chloride with tri-n-octyl amine (TOA from aqueous solutions

    Directory of Open Access Journals (Sweden)

    DJORDJE M. PETKOVIC

    2001-07-01

    Full Text Available Extraction of uranyl nitrate, chloride and sulphate with tri-n-octyl amine (TOA in benzene as a function of the TOA concentration has been studied. The concentration based extraction equilibrium constants were calculated from the distribution data of the uranyl salts, fitting the parameters of a chemical model to the experimentally obtained extraction isotherms. The calculated equilibrium constants are 46.5, 89.4 and 4.2·104 for uranyl nitrate, chloride and sulphate, respectively. These values are in good agreement with the previously reported extraction equilibrium constants calculated by the inflection point method.

  1. Phase diagram of ammonium nitrate

    Science.gov (United States)

    Dunuwille, M.; Yoo, C. S.

    2014-05-01

    Ammonium Nitrate (AN) has often subjected to uses in improvised explosive devices, due to its wide availability as a fertilizer and its capability of becoming explosive with slight additions of organic and inorganic compounds. Yet, the origin of enhanced energetic properties of impure AN (or AN mixtures) is neither chemically unique nor well understood -resulting in rather catastrophic disasters in the past1 and thereby a significant burden on safety in using ammonium nitrates even today. To remedy this situation, we have carried out an extensive study to investigate the phase stability of AN at high pressure and temperature, using diamond anvil cells and micro-Raman spectroscopy. The present results confirm the recently proposed phase IV-to-IV' transition above 17 GPa2 and provide new constraints for the melting and phase diagram of AN to 40 GPa and 400 °C.

  2. Contributions of two cytosolic glutamine synthetase isozymes to ammonium assimilation in Arabidopsis roots.

    Science.gov (United States)

    Konishi, Noriyuki; Ishiyama, Keiki; Beier, Marcel Pascal; Inoue, Eri; Kanno, Keiichi; Yamaya, Tomoyuki; Takahashi, Hideki; Kojima, Soichi

    2016-12-21

    Glutamine synthetase (GS) catalyzes a reaction that incorporates ammonium into glutamate and yields glutamine in the cytosol and chloroplasts. Although the enzymatic characteristics of the GS1 isozymes are well known, their physiological functions in ammonium assimilation and regulation in roots remain unclear. In this study we show evidence that two cytosolic GS1 isozymes (GLN1;2 and GLN1;3) contribute to ammonium assimilation in Arabidopsis roots. Arabidopsis T-DNA insertion lines for GLN1;2 and GLN1;3 (i.e. gln1;2 and gln1;3 single-mutants), the gln1;2:gln1;3 double-mutant, and the wild-type accession (Col-0) were grown in hydroponic culture with variable concentrations of ammonium to compare their growth, and their content of nitrogen, carbon, ammonium, and amino acids. GLN1;2 and GLN1;3 promoter-dependent green fluorescent protein was observed under conditions with or without ammonium supply. Loss of GLN1;2 caused significant suppression of plant growth and glutamine biosynthesis under ammonium-replete conditions. In contrast, loss of GLN1;3 caused slight defects in growth and Gln biosynthesis that were only visible based on a comparison of the gln1;2 single- and gln1;2:gln1;3 double-mutants. GLN1;2, being the most abundantly expressed GS1 isozyme, markedly increased following ammonium supply and its promoter activity was localized at the cortex and epidermis, while GLN1;3 showed only low expression at the pericycle, suggesting their different physiological contributions to ammonium assimilation in roots. The GLN1;2 promoter-deletion analysis identified regulatory sequences required for controlling ammonium-responsive gene expression of GLN1;2 in Arabidopsis roots. These results shed light on GLN1 isozyme-specific regulatory mechanisms in Arabidopsis that allow adaptation to an ammonium-replete environment.

  3. Ammonium assimilation: An important accessory during aerobic denitrification of Pseudomonas stutzeri T13.

    Science.gov (United States)

    Sun, Yilu; Feng, Liang; Li, Ang; Zhang, Xuening; Yang, Jixian; Ma, Fang

    2017-03-12

    The present study investigated effect of ammonium utilization on aerobic denitrification by Pseudomonas stutzeri T13. Per nitrogen balance calculation, all consumed ammonium was utilized as nitrogen source for cell propagation by assimilation rather than heterotrophic nitrification. Total organic carbon (TOC) and ammonium were necessary substrates to sustain heterotrophic propagation of P. stutzeri T13 at optimum proportion equal to seven. Under aerobic condition, nitrate was utilized as substitute nitrogen source when ammonium was completely exhausted. Biomass production effectively increased with increasing initial ammonium from 0mg/L to 100mg/L. Owing to enlarged biomass, average nitrate reduction rate increased from 7.36mgL(-1)h(-1) to 11.95mgL(-1)h(-1). Such process also successfully reduced nitrite accumulation from 121.8mg/L to 66.16mg/L during aerobic denitrification. As important accessory during aerobic denitrification, ammonium assimilation efficiently doubled total nitrogen (TN) removal from 54.97mg/L (no ammonium provided) to 113.1mg/L (100mg/L ammonium involved).

  4. Uptake of uranyl ions from uranium ores and sludges by means of Spirulina platensis, Porphyridium cruentum and Nostok linckia alga.

    Science.gov (United States)

    Cecal, Alexandru; Humelnicu, Doina; Rudic, Valeriu; Cepoi, Liliana; Ganju, Dumitru; Cojocari, Angela

    2012-08-01

    In this paper was studied the uranyl ions biosorption on three types of alga: Nostok linckia, Porphyridium cruentum and Spirulina platensis. These ions were supplied either from a pure solution of uranyl nitrate, or after leaching process of uranium ore, or from the sludge resulting in the output of pure UO(2) technology. It was investigated the retention degree versus contact time and afterwards the Langmuir and Freundlich biosorption isotherms of uranyl ions on the three alga types. The retention of UO(2)(2+) ions on alga was proved through FTIR spectra plotted before and after biosorption processes. From the experimental data it was found that regardless of origin of uranyl ions, the retention degree on alga decreased in the series. Spirulina platensis > Porphyridium cruentum ≥ Nostok linckia.

  5. 流加补氨水代替碳酸钙在赤霉素GA4+7生物发酵中的研究%Study of Replacing Calcium Carbonate with Ammonium Feeding in Gibberellins A4+7 Fermentation

    Institute of Scientific and Technical Information of China (English)

    张文宣; 刘义雄; 周圣骄; 谷田; 钟名兴

    2011-01-01

    Effects of replacing calcium carbonate with ammonium feeding in gibberellins GA4+7 fermentation and recovered rate were studied. The research showed that the continuous ammonium feeding technique could be utilized in gibberellins GA4+7 fermentation and production, and could positively enhance the production of gibberellins GA4+7. The yield/titer was 6% higher than control and recovered rate was 4% higher because the negative effect of calcium on nltrafiltration membrane (NF) and nanofiltration membrane (NF) was eliminated.%研究了在赤霉素GA4+7生物发酵过程中,流加补氨水代替碳酸钙精确调控发酵pH对发酵与提炼的影响,结果表明流加补氨水代替碳酸钙工艺可应用于赤霉素GA4+7发酵生产中,对赤霉素GA4+7发酵具有促进作用。其能提高发酵水平6%以上,同时因消除了钙离子对膜分离的影响,可提高后提取工艺收率4%以上。

  6. Synthesis of Chitosan Quaternary Ammonium Salts

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    A series of N-alkyl or N-aryl chitosan quaternary ammonium salts were prepared via Schiffs base intermediates. Quaternization of N-substituted chitosan derivatives was carried out using methyl iodide to produce water-soluble cationic chitosan quaternary ammonium salt. The products were characterized by IR, 1HNMR and elemental analysis. The degree of substitution of chitosan quaternary ammonium salt was calculated by elemental analysis.

  7. Effect of uranyl intoxication on renal corticomedullary gradient of orthoiodohippurate in laboratory rat

    Energy Technology Data Exchange (ETDEWEB)

    Vlcek, J.; Kvetina, J. (Karlova Univ., Hradec Kralove (Czechoslovakia). Farmaceuticka Fakulta)

    1983-08-05

    The assessment is attempted of the intrarenal distribution (by means of the cortico-medullary gradient and the cortico-pelvic gradient) of a model diagnostic substance (O-/sup 125/I-hippurate) for the analysis of mechanisms causing damage to the renal function during intoxication induced by uranyl ions (uranyl nitrate). The findings were correlated with other indicators of the renal lesion (creatinine and urea plasma levels). Relative shifts of different gradients, i.e. mutual shifts and shifts in relation to hippurate blood levels, make it possible to describe the stepwise character of functional changes in the damaged kidney. The method used is suitable for investigating the dynamics of substances transport during functional renal changes in particular when combined with the determination the intensity of the uptake of model substances by renal tissue slices.

  8. Spectroscopic study on uranyl carboxylate complexes formed at the surface layer of Sulfolobus acidocaldarius.

    Science.gov (United States)

    Reitz, Thomas; Rossberg, Andre; Barkleit, Astrid; Steudtner, Robin; Selenska-Pobell, Sonja; Merroun, Mohamed L

    2015-02-14

    The complexation of U(vi) at the proteinaceous surface layer (S-layer) of the archaeal strain Sulfolobus acidocaldarius was investigated over a pH range from pH 1.5 to 6 at the molecular scale using time-resolved laser-induced fluorescence spectroscopy (TRLFS) and U L(III)-edge extended X-ray absorption fine structure (EXAFS). The S-layer, which represents the interface between the cell and its environment, is very stable against high temperatures, proteases, and detergents. This allowed the isolation and purification of S-layer ghosts (= empty cells) that maintain the size and shape of the cells. In contrast to many other microbial cell envelope compounds the studied S-layer is not phosphorylated, enabling the investigation of uranyl carboxylate complexes formed at microbial surfaces. The latter are usually masked by preferentially formed uranyl phosphate complexes. We demonstrated that at highly acidic conditions (pH 1.5 to 3) no uranium was bound by the S-layer. In contrast to that, at moderate acidic pH conditions (pH 4.5 and 6) a complexation of U(vi) at the S-layer via deprotonated carboxylic groups was stimulated. Titration studies revealed dissociation constants for the carboxylic groups of glutamic and aspartic acid residues of pK(a) = 4.78 and 6.31. The uranyl carboxylate complexes formed at the S-layer did not show luminescence properties at room temperature, but only under cryogenic conditions. The obtained luminescence maxima are similar to those of uranyl acetate. EXAFS spectroscopy demonstrated that U(vi) in these complexes is mainly coordinated to carboxylate groups in a bidentate binding mode. The elucidation of the molecular structure of these complexes was facilitated by the absence of phosphate groups in the studied S-layer protein.

  9. Coordination mode of nitrate in uranyl(VI) complexes: a first-principles molecular dynamics study.

    Science.gov (United States)

    Bühl, Michael; Diss, Romain; Wipff, Georges

    2007-06-25

    According to Car-Parrinello molecular dynamics simulations for [UO(2)(NO(3))(3)](-), [UO(2)(NO(3))(4)](2-), and [UO(2)(OH(2))(4-)(NO(3))](+) complexes in the gas phase and in aqueous solution, the nitrate coordination mode to uranyl depends on the interplay between ligand-metal attractions, interligand repulsions, and solvation. In the trinitrate, the eta(2)-coordination is clearly favored in water and in the gas phase, leading to a coordination number (CN) of 6. According to pointwise thermodynamic integration involving constrained molecular dynamics simulations, a change in free energy of +6 kcal/mol is predicted for eta(2)- to eta(1)-transition of one of the three nitrate ligands in the gas phase. In the gas phase, the mononitrate-hydrate complex also prefers a eta(2)-binding mode but with a CN of 5, one H(2)O molecule being in the second shell. This contrasts with the aqueous solution where the nitrate binds in a eta(1)-fashion and uranyl coordinates to four H2O ligands. A driving force of ca. -3 kcal/mol is predicted for the eta(2)- to eta(1)- transition in water. This structural preference is interpreted in terms of steric arguments and differential solvation of terminal vs uranyl-coordinated O atoms of the nitrate ligands. The [UO(2)(NO(3))(4)](2-) complex with two eta(2)- and two eta(1)- coordinated nitrates, observed in the solid state, is stable for 1-2 ps in the gas phase and in solution. In the studied series, the modulation of uranyl-ligand distances upon immersion of the complex in water is found to depend on the nature of the ligand and the composition of the complex.

  10. Determination of uranyl incorporation into biogenic manganese oxides using X-ray absorption spectroscopy and scattering

    Science.gov (United States)

    Webb, S.M.; Fuller, C.C.; Tebo, B.M.; Bargar, J.R.

    2006-01-01

    Biogenic manganese oxides are common and an important source of reactive mineral surfaces in the environment that may be potentially enhanced in bioremediation cases to improve natural attenuation. Experiments were performed in which the uranyl ion, UO22+ (U(VI)), at various concentrations was present during manganese oxide biogenesis. At all concentrations, there was strong uptake of U onto the oxides. Synchrotron-based extended X-ray absorption fine structure (EXAFS) spectroscopy and X-ray diffraction (XRD) studies were carried out to determine the molecular-scale mechanism by which uranyl is incorporated into the oxide and how this incorporation affects the resulting manganese oxide structure and mineralogy. The EXAFS experiments show that at low concentrations (2 mol % U, >4 ??M U(VI) in solution), the presence of U(VI) affects the stability and structure of the Mn oxide to form poorly ordered Mn oxide tunnel structures, similar to todorokite. EXAFS modeling shows that uranyl is present in these oxides predominantly in the tunnels of the Mn oxide structure in a tridentate complex. Observations by XRD corroborate these results. Structural incorporation may lead to more stable U(VI) sequestration that may be suitable for remediation uses. These observations, combined with the very high uptake capacity of the Mn oxides, imply that Mn-oxidizing bacteria may significantly influence dissolved U(VI) concentrations in impacted waters via sorption and incorporation into Mn oxide biominerals. ?? 2006 American Chemical Society.

  11. A relativistic density functional study of uranyl hydrolysis and complexation by carboxylic acids in aqueous solution

    Energy Technology Data Exchange (ETDEWEB)

    Ray, Rupashree Shyama

    2009-02-10

    In this work, the complexation of uranium in its most stable oxidation state VI in aqueous solution was studied computationally, within the framework of density functional (DF) theory. The thesis is divided into the following parts: Chapter 2 briefly summarizes the relevant general aspects of actinide chemistry and then focuses on actinide environmental chemistry. Experimental results on hydrolysis, actinide complexation by carboxylic acids, and humic substances are presented to establish a background for the subsequent discussion. Chapter 3 describes the computational method used in this work and the relevant features of the parallel quantum chemistry code PARAGAUSS employed. First, the most relevant basics of the applied density functional approach are presented focusing on relativistic effects. Then, the treatment of solvent effects, essential for an adequate modeling of actinide species in aqueous solution, will be introduced. At the end of this chapter, computational parameters and procedures will be summarized. Chapter 4 presents the computational results including a comparison to available experimental data. In the beginning, the mononuclear hydrolysis product of UO{sub 2}{sup 2+}, [UO{sub 2}OH]{sup +}, will be discussed. The second part deals with actinide complexation by carboxylate ligands. First of all the coordination number for uranylacetate will be discussed with respect to implications for the complexation of actinides by humic substances followed by the uranyl complexation of aromatic carboxylic acids in comparison to earlier results for aliphatic ones. In the end, the ternary uranyl-hydroxo-acetate are discussed, as models of uranyl humate complexation at ambient condition.

  12. 49 CFR 176.410 - Division 1.5 materials, ammonium nitrate and ammonium nitrate mixtures.

    Science.gov (United States)

    2010-10-01

    ... 49 Transportation 2 2010-10-01 2010-10-01 false Division 1.5 materials, ammonium nitrate and ammonium nitrate mixtures. 176.410 Section 176.410 Transportation Other Regulations Relating to... nitrate and ammonium nitrate mixtures. (a) This section prescribes requirements to be observed...

  13. 33 CFR 126.28 - Ammonium nitrate, ammonium nitrate fertilizers, fertilizer mixtures, or nitro carbo nitrate...

    Science.gov (United States)

    2010-07-01

    ... 33 Navigation and Navigable Waters 2 2010-07-01 2010-07-01 false Ammonium nitrate, ammonium nitrate fertilizers, fertilizer mixtures, or nitro carbo nitrate; general provisions. 126.28 Section 126...) WATERFRONT FACILITIES HANDLING OF DANGEROUS CARGO AT WATERFRONT FACILITIES § 126.28 Ammonium...

  14. An investigation of the interactions of Eu³⁺ and Am³⁺ with uranyl minerals: implications for the storage of spent nuclear fuel.

    Science.gov (United States)

    Biswas, Saptarshi; Steudtner, Robin; Schmidt, Moritz; McKenna, Cora; León Vintró, Luis; Twamley, Brendan; Baker, Robert J

    2016-04-21

    The reaction of a number of uranyl minerals of the (oxy)hydroxide, phosphate and carbonate types with Eu(iii), as a surrogate for Am(iii), have been investigated. A photoluminescence study shows that Eu(iii) can interact with the uranyl minerals Ca[(UO2)6(O)4(OH)6]·8H2O (becquerelite) and A[UO2(CO3)3]·xH2O (A/x = K3Na/1, grimselite; CaNa2/6, andersonite; and Ca2/11, liebigite). For the minerals [(UO2)8(O)2(OH)12]·12H2O (schoepite), K2[(UO2)6(O)4(OH)6]·7H2O (compreignacite), A[(UO2)2(PO4)2]·8H2O (A = Ca, meta-autunite; Cu, meta-torbernite) and Cu[(UO2)2(SiO3OH)2]·6H2O (cuprosklodowskite) no Eu(iii) emission was observed, indicating no incorporation into, or sorption onto the structure. In the examples with Eu(3+) incorporation, sensitized emission is seen and the lifetimes, hydration numbers and quantum yields have been determined. Time Resolved Laser Induced Fluroescence Spectroscpoy (TRLFS) at 10 K have also been measured and the resolution enhancements at these temperatures allow further information to be derived on the sites of Eu(iii) incorporation. Infrared and Raman spectra are recorded, and SEM analysis show significant morphology changes and the substitution of particularly Ca(2+) by Eu(3+) ions. Therefore, Eu(3+) can substitute Ca(2+) in the interlayers of becquerelite and liebigite and in the structure of andersonite, whilst in grimselite only sodium is exchanged. These results have guided an investigation into the reactions with (241)Am on a tracer scale and results from gamma-spectrometry show that becquerelite, andersonite, grimselite, liebigite and compreignacite can include americium in the structure. Shifts in the U[double bond, length as m-dash]O and C-O Raman active bands are similar to that observed in the Eu(iii) analogues and Am(iii) photoluminescence measurements are also reported on these phases; the Am(3+) ion quenches the emission from the uranyl ion.

  15. Equilibrium studies of sodium-ammonium potassium-ammonium, and calcium-ammonium exchanges on clinoptilolite zeolite

    Energy Technology Data Exchange (ETDEWEB)

    Jama, M.A.; Yuecel, H. (Middle East Technical Univ., Ankara (Turkey))

    1989-12-01

    Forward and reverse ion-exchange isotherms for the binary sodium-ammonium, potassium-ammonium, and calcium-ammonium systems on clinoptilolite have been measured in aqueous solutions at a total concentration of 0.1 equiv/dm{sup 3} and at 298 K. Prior to exchange experiments it was attempted to prepare homoionic forms of the zeolite by exhaustive treatments with appropriate salt solutions of cations. With no binary exchanges, full replacement of the cation by the ammonium ion is observed, which conflicts with some earlier work on clinoptilolite. Despite the observed partial exchange levels, clinoptilolite shows a very high preference for ammonium ion over sodium and calcium but not over potassium. Thermodynamic values for the exchanges were calculated and compared with data in the literature. Both the selectivity and thermodynamic affinity sequence, in agreement with previous work reported in the literature, are K{sup +} > NH{sub 4}{sup +} > Na{sup +} > Ca{sup 2+}.

  16. Gas-phase reactions of molecular oxygen with uranyl(V) anionic complexes-synthesis and characterization of new superoxides of uranyl(VI).

    Science.gov (United States)

    Lucena, Ana F; Carretas, José M; Marçalo, Joaquim; Michelini, Maria C; Gong, Yu; Gibson, John K

    2015-04-16

    Gas-phase complexes of uranyl(V) ligated to anions X(-) (X = F, Cl, Br, I, OH, NO3, ClO4, HCO2, CH3CO2, CF3CO2, CH3COS, NCS, N3), [UO2X2](-), were produced by electrospray ionization and reacted with O2 in a quadrupole ion trap mass spectrometer to form uranyl(VI) anionic complexes, [UO2X2(O2)](-), comprising a superoxo ligand. The comparative rates for the oxidation reactions were measured, ranging from relatively fast [UO2(OH)2](-) to slow [UO2I2](-). The reaction rates of [UO2X2](-) ions containing polyatomic ligands were significantly faster than those containing the monatomic halogens, which can be attributed to the greater number of vibrational degrees of freedom in the polyatomic ligands to dissipate the energy of the initial O2-association complexes. The effect of the basicity of the X(-) ligands was also apparent in the relative rates for O2 addition, with a general correlation between increasing ligand basicity and O2-addition efficiency for polyatomic ligands. Collision-induced dissociation of the superoxo complexes showed in all cases loss of O2 to form the [UO2X2](-) anions, indicating weaker binding of the O2(-) ligand compared to the X(-) ligands. Density functional theory computations of the structures and energetics of selected species are in accord with the experimental observations.

  17. Heterotrophic ammonium removal characteristics of an aerobic heterotrophic nitrifying-denitrifying bacterium, Providencia rettgeri YL

    Institute of Scientific and Technical Information of China (English)

    TAYLOR Shauna M; HE Yiliang; ZHAO Bin; HUANG Jue

    2009-01-01

    Bacterium Providencia rettgeri YL was found to exhibit an unusual ability to heterotrophically nitrify and aerobically denitrify various concentrations of ammonium (NH4+-N). In order to further analyze its removal ability, several experiments were conducted to identify the growth and ammonium removal response in different carbon to nitrogen (C/N) mass ratios, shaking speeds, temperatures, ammonium concentrations and to qualitatively verify the production of nitrogen gas using gas chromatography techniques. Results showed that under optimum conditions (C/N 10, 30℃, 120 r/min), YL can significantly remove low and high concentrations of ammonium within 12 to 48 h of growth. The nitrification products hydroxylamine (NH2OH), nitrite (NO2-) and nitrate (NO3-) as well as the denitrification product, nitrogen gas (N2), were detected under completely aerobic conditions.

  18. Biodegradation of rocket propellant waste, ammonium perchlorate

    Science.gov (United States)

    Naqvi, S. M. Z.; Latif, A.

    1975-01-01

    The short term effects of ammonium perchlorate on selected organisms were studied. A long term experiment was also designed to assess the changes incurred by ammonium perchlorate on the nitrogen and chloride contents of soil within a period of 3 years. In addition, an attempt was made to produce methane gas from anaerobic fermentation of the aquatic weed, Alternanthera philoxeroides.

  19. Effects of ammonium concentration and charge exchange on ammonium recovery from high strength wastewater using a microbial fuel cell

    NARCIS (Netherlands)

    Kuntke, P.; Geleij, M.; Bruning, H.; Zeeman, G.; Hamelers, H.V.M.; Buisman, C.J.N.

    2011-01-01

    Ammonium recovery using a 2 chamber microbial fuel cell (MFC) was investigated at high ammonium concentration. Increasing the ammonium concentration (from 0.07 g to 4 g ammonium-nitrogen/L) by addition of ammonium chloride did not affect the performance of the MFC. The obtained current densities by

  20. 49 CFR 176.415 - Permit requirements for Division 1.5, ammonium nitrates, and certain ammonium nitrate fertilizers.

    Science.gov (United States)

    2010-10-01

    ... nitrates, and certain ammonium nitrate fertilizers. 176.415 Section 176.415 Transportation Other... requirements for Division 1.5, ammonium nitrates, and certain ammonium nitrate fertilizers. (a) Except as... Captain of the Port (COTP). (1) Ammonium nitrate UN1942, ammonium nitrate fertilizers containing more...

  1. Cytotoxicity effect assessment of acid purified carbon nanotubes modified with cetyltrimethyl ammonium bromide%十六烷基三甲基溴化铵修饰的羧基化单壁碳纳米管的细胞毒性

    Institute of Scientific and Technical Information of China (English)

    甘丽; 阎雪彬; 杨金凤; 谷永红; 黄东; 章饶香; 黄利华

    2013-01-01

    The cytotoxicities of single-walled carbon nanotubes (SWNTs) and acid purified single-walled carbon nanotubes (SWNT-COOH) were investigated by spectroscopic analysis. Cell viability and cell apoptosis were applied to assessing the cytotoxicity of SWNT-COOH, cetyltrimethyl ammonium bromide (CTAB) and acid purified carbon nanotubes modified with cetyltrimethyl ammonium bromide (SWNT-COOH/CTAB). The results indicate that SWNTs are more toxic than SWNT-COOH. Concentration and time-curve analyses indicate that cytotoxicity of SWNT-COOH/CTAB is more related to the toxicity of the surfactant CTAB. The cytotoxicity effect of CTAB and SWNT-COOH/CTAB is acceptable at low concentrations (0.5-25μg/mL). The cytotoxicity observation suggests that SWNT-COOH/CTAB can safely applied to biomedical field at low concentrations (0.5-25μg/mL).%采用十六烷基三甲基溴化铵(CTAB)作为表面活性剂修饰羧基化的单壁碳纳米管(SWNT-COOH/CTAB),并对原始单壁碳纳米管(SWNTs)与羧基化修饰的单壁碳纳米管(SWNT-COOH)进行材料学特征比较。通过细胞活力和细胞凋亡实验对SWNTs、SWNT-COOH和SWNT-COOH/CTAB的细胞毒性进行比较。结果表明,羧基化修饰的单壁碳纳米管比原始单壁碳纳米管的毒性小,单壁碳纳米管经羧基化后其毒性降低;浓度及时间曲线显示SWNT-COOH/CTAB的毒性与表面活性剂CTAB相关,CTAB和 SWNT-COOH/CTAB的细胞毒性在低浓度范围内(0.5~25μg/mL)是可接受的。十六烷基三甲基溴化铵修饰的羧基化单壁碳纳米管在低浓度范围(0.5~25μg/mL)内可以较安全地用于生物医学领域。

  2. The nucleation kinetics of ammonium metavanadate precipitated by ammonium chloride

    Science.gov (United States)

    Du, Guangchao; Sun, Zhaohui; Xian, Yong; Jing, Han; Chen, Haijun; Yin, Danfeng

    2016-05-01

    The nucleation kinetics of ammonium metavanadate (NH4VO3) was investigated under conditions of the simulated process for precipitation of NH4VO3 from the vanadium-containing solution. Induction periods for the nucleation of NH4VO3 were experimentally determined as a function of supersaturation at temperatures from 30 to 45 °C. Using the classical nucleation theory, the interfacial tension between NH4VO3 and supersaturated solution, the nucleation rate and critical radius of nucleus for the homogeneous nucleation of NH4VO3 were estimated. With temperature increasing, the calculated interfacial tension gradually decreased from 29.78 mJ/m2 at 30 °C to 23.66 mJ/m2 at 45 °C. The nucleation rate was found to proportionally increase but the critical radius of nucleus exponentially decreased, with increase in supersaturation ratio at a constant temperature. The activation energy for NH4VO3 nucleation was obtained from the relationship between temperature and induction period, ranging from 79.17 kJ/mol at S=25 to 115.50 kJ/mol at S=15. FT-IR and Raman spectrum indicated that the crystals obtained in the precipitation process were NH4VO3.

  3. Ammonium photo-production by heterocytous cyanobacteria: potentials and constraints.

    Science.gov (United States)

    Grizeau, Dominique; Bui, Lan Anh; Dupré, Catherine; Legrand, Jack

    2016-08-01

    Over the last decades, production of microalgae and cyanobacteria has been developed for several applications, including novel foods, cosmetic ingredients and more recently biofuel. The sustainability of these promising developments can be hindered by some constraints, such as water and nutrient footprints. This review surveys data on N2-fixing cyanobacteria for biomass production and ways to induce and improve the excretion of ammonium within cultures under aerobic conditions. The nitrogenase complex is oxygen sensitive. Nevertheless, nitrogen fixation occurs under oxic conditions due to cyanobacteria-specific characteristics. For instance, in some cyanobacteria, the vegetative cell differentiation in heterocyts provides a well-adapted anaerobic microenvironment for nitrogenase protection. Therefore, cell cultures of oxygenic cyanobacteria have been grown in laboratory and pilot photobioreactors (Dasgupta et al., 2010; Fontes et al., 1987; Moreno et al., 2003; Nayak & Das, 2013). Biomass production under diazotrophic conditions has been shown to be controlled by environmental factors such as light intensity, temperature, aeration rate, and inorganic carbon concentration, also, more specifically, by the concentration of dissolved oxygen in the culture medium. Currently, there is little information regarding the production of extracellular ammonium by heterocytous cyanobacteria. This review compares the available data on maximum ammonium concentrations and analyses the specific rate production in cultures grown as free or immobilized filamentous cyanobacteria. Extracellular production of ammonium could be coupled, as suggested by recent research on non-diazotrophic cyanobacteria, to that of other high value metabolites. There is little information available regarding the possibility for using diazotrophic cyanobacteria as cellular factories may be in regard of the constraints due to nitrogen fixation.

  4. Selective recognition of uranyl ions from bulk of thorium(iv) and lanthanide(iii) ions by tetraalkyl urea: a combined experimental and quantum chemical study.

    Science.gov (United States)

    Vats, Bal Govind; Das, Debasish; Sadhu, Biswajit; Kannan, S; Pius, I C; Noronha, D M; Sundararajan, Mahesh; Kumar, Mukesh

    2016-06-21

    The selective separation of uranyl ions from an aqueous solution is one of the most important criteria for sustainable nuclear energy production. We report herein a known, but unexplored extractant, tetraalkyl urea, which shows supreme selectivity for uranium in the presence of interfering thorium and other lanthanide ions from a nitric acid medium. The structural characterization of the uranyl complex (UO2X2·2L, where X = NO3(-), Cl(-) and Br(-)) by IR, NMR and single crystal X-ray diffraction provides insight into the strong interaction between the uranyl ion and the ligand. The origin of this supreme selectivity for uranyl ions is further supported by electronic structure calculations. Uranyl binding with the extractant is thermodynamically more favourable when compared to thorium and the selectivity is achieved through a combination of electronic and steric effects.

  5. Substrate specificity of Rhbg: ammonium and methyl ammonium transport.

    Science.gov (United States)

    Nakhoul, Nazih L; Abdulnour-Nakhoul, Solange M; Boulpaep, Emile L; Rabon, Edd; Schmidt, Eric; Hamm, L Lee

    2010-09-01

    Rhbg is a nonerythroid membrane glycoprotein belonging to the Rh antigen family. In the kidney, Rhbg is expressed at the basolateral membrane of intercalated cells of the distal nephron and is involved in NH4+ transport. We investigated the substrate specificity of Rhbg by comparing transport of NH3/NH4+ with that of methyl amine (hydrochloride) (MA/MA+), often used to replace NH3/NH4+, in oocytes expressing Rhbg. Methyl amine (HCl) in solution exists as neutral methyl amine (MA) in equilibrium with the protonated methyl ammonium (MA+). To assess transport, we used ion-selective microelectrodes and voltage-clamp experiments to measure NH3/NH4+- and MA/MA+-induced intracellular pH (pH(i)) changes and whole cell currents. Our data showed that in Rhbg oocytes, NH3/NH4+ caused an inward current and decrease in pH(i) consistent with electrogenic NH4+ transport. These changes were significantly larger than in H2O-injected oocytes. The NH3/NH4+-induced current was not inhibited in the presence of barium or in the absence of Na+. In Rhbg oocytes, MA/MA+ caused an inward current but an increase (rather than a decrease) in pH(i). MA/MA+ did not cause any changes in H2O-injected oocytes. The MA/MA+-induced current and pH(i) increase were saturated at higher concentrations of MA/MA+. Amiloride inhibited MA/MA+-induced current and the increase in pH(i) in oocytes expressing Rhbg but had no effect on control oocytes. These results indicate that MA/MA+ is transported by Rhbg but differently than NH3/NH4+. The protonated MA+ is likely a direct substrate whose transport resembles that of NH4+. Transport of electroneutral MA is also enhanced by expression of Rhbg.

  6. FY-15 Progress Report on Cleanup of irradiated SHINE Target Solutions Containing 140g-U/L Uranyl Sulfate

    Energy Technology Data Exchange (ETDEWEB)

    Bennett, Megan E. [Argonne National Lab. (ANL), Argonne, IL (United States); Bowers, Delbert L. [Argonne National Lab. (ANL), Argonne, IL (United States); Vandegrift, George F. [Argonne National Lab. (ANL), Argonne, IL (United States)

    2015-09-01

    During FY 2012 and 2013, a process was developed to convert the SHINE Target Solution (STS) of irradiated uranyl sulfate (140 g U/L) to uranyl nitrate. This process is necessary so that the uranium solution can be processed by the UREX (Uranium Extraction) separation process, which will remove impurities from the uranium so that it can be recycled. The uranyl sulfate solution must contain <0.02 M SO42- so that the uranium will be extractable into the UREXsolvent. In addition, it is desired that the barium content be below 0.0007 M, as this is the limit in the Resource Conservation and Recovery Act (RCRA).

  7. Chiral ammonium betaine-catalyzed asymmetric Mannich-type reaction of oxindoles

    Directory of Open Access Journals (Sweden)

    Masahiro Torii

    2016-09-01

    Full Text Available A highly diastereo- and enantioselective Mannich-type reaction of 3-aryloxindoles with N-Boc aldimines was achieved under the catalysis of axially chiral ammonium betaines. This catalytic method provides a new tool for the construction of consecutive quaternary and tertiary stereogenic carbon centers on biologically intriguing molecular frameworks with high fidelity.

  8. Selective Se-for-S substitution in Cs-bearing uranyl compounds

    Science.gov (United States)

    Gurzhiy, Vladislav V.; Tyumentseva, Olga S.; Krivovichev, Sergey V.; Tananaev, Ivan G.

    2017-04-01

    Phase formation in the mixed sulfate-selenate aqueous system of uranyl nitrate and cesium nitrate has been investigated. Two types of crystalline compounds have been obtained and characterized using a number of experimental (single crystal XRD, FTIR, SEM) and theoretical (information-based complexity calculations, topological analysis) techniques. No miscibility gaps have been observed for Cs2[(UO2)2(TO4)3] (T= S, Se), which crystallizes in tetragonal system, P-421m, a =9.616(1)-9.856(2), c =8.105(1)-8.159(1) Å, V =749.6(2)-792.5(3) Å3. Nine phases with variable amount of S and Se have been structurally characterized. The structures of the Cs2[(UO2)2(TO4)3] (T= S, Se) compounds are based upon the [(UO2)2(TO4)3]2- layers of corner-sharing uranyl pentagonal bipyramids and TO4 tetrahedra. The layers contain two types of tetrahedral sites: T1 (3-connected, i.e. having three O atoms shared by adjacent uranyl polyhedra) and T2 (4-connected). The Se-for-S substitution in tetrahedral sites is highly selective with smaller S6+ cation showing a strong preference for the more tightly bonded T2 site. Crystallization in the pure Se system starts with the formation of Cs2[(UO2)(SeO4)2(H2O)](H2O) crystals, its subsequent dissolution and formation of Cs2[(UO2)2(SeO4)3]. The information-based structural complexity calculations for these two phases support the rule that more topologically complex structures form at the latest stages of crystallization.

  9. Computer simulation of uranyl uptake by the rough lipopolysaccharide membrane of Pseudomonas aeruginosa.

    Science.gov (United States)

    Lins, Roberto D; Vorpagel, Erich R; Guglielmi, Matteo; Straatsma, T P

    2008-01-01

    Heavy metal environmental contaminants cannot be destroyed but require containment, preferably in concentrated form, in a solid or immobile form for recycling or final disposal. Microorganisms are able to take up and deposit high levels of contaminant metals, including radioactive metals such as uranium and plutonium, into their cell wall. Consequently, these microbial systems are of great interest as the basis for potential environmental bioremediation technologies. The outer membranes of Gram-negative microbes are highly nonsymmetric and exhibit a significant electrostatic potential gradient across the membrane. This gradient has a significant effect on the uptake and transport of charged and dipolar compounds. However, the effectiveness of microbial systems for environmental remediation will depend strongly on specific properties that determine the uptake of targeted contaminants by a particular cell wall. To aid in the design of microbial remediation technologies, knowledge of the factors that determine the affinity of a particular bacterial outer membrane for the most common ionic species found in contaminated soils and groundwater is of great importance. Using our previously developed model for the lipopolysaccharide (LPS) membrane of Pseudomonas aeruginosa, this work presents the potentials of mean force as the estimate of the free energy profile for uptake of sodium, calcium, chloride, uranyl ions, and a water molecule by the bacterial LPS membrane. A compatible classical parameter set for uranyl has been developed and validated. Results show that the uptake of uranyl is energetically a favorable process relative to the other ions studied. At neutral pH, this nuclide is shown to be retained on the surface of the LPS membrane through chelation with the carboxyl and hydroxyl groups located in the outer core.

  10. Isolation and identification of bacteria responsible for simultaneous anaerobic ammonium and sulfate removal

    Institute of Scientific and Technical Information of China (English)

    2010-01-01

    Sulfate-dependent anaerobic ammonium oxidation is a novel biological reaction,in which ammonium is oxidized with sulfate as the electron acceptor under anoxic conditions.Ammonium and sulfate are cosmopolitan chemical species which are an integral part of the global nitrogen and sulfur cycles.A detailed exploration of sulfate-dependent anaerobic ammonium oxidation is quite practical.In this work,a bacterial strain named ASR has been isolated from an anaerobic ammonia and sulfate removing reactor working under steady-state.On the basis of electron microscopy,physiological tests and 16S rDNA phylogenetic sequence analysis,the strain ASR is found to be related to Bacillus benzoevorans.According to the biological carbon source utilization test,the strain ASR could use many carbon sources.Its optimum pH value and temperature were 8.5 and 30 °C,respectively.The test proves that the strain ASR is able to use sulfate to oxidize ammonia anaerobically.The maximum ammonia and sulfate removal rates were 44.4% and 40.0%,respectively.The present study provided biological evidence for the confirmation and development of sulfate-dependent anaerobic ammonium oxidation and brought new insights into the global nitrogen and sulfur cycles.

  11. Synthesis, characterization and photo luminescence studies of uranyl doped SrBPO{sub 5}

    Energy Technology Data Exchange (ETDEWEB)

    Rout, Annapurna; Suriyamurthy, N.; Panigrahi, B. S., E-mail: bsp@igcar.gov.in [Indira Gandhi Centre for Atomic Research, Kalpakkam – 603 102 (India)

    2015-06-24

    SrBPO{sub 5}: UO{sub 2}{sup 2+} was synthesized using solid state reaction method and characterized using powder X-ray diffraction. PXRD data showed the formation of single phase confirming successful doping of UO{sub 2}{sup 2+}. Photo luminescence investigation informed stabilization of Uranium as Uranyl (UO{sub 2}{sup 2+}) in SrBPO{sub 5} matrix. Luminescence decay time data suggested two possible environments for UO{sub 2}{sup 2+} with two different life time values.

  12. New complexes of heteroaromatic N-oxides with europium, uranyl and zinc ions

    Institute of Scientific and Technical Information of China (English)

    Zbigniew Hnatejko

    2012-01-01

    New solid complexes of europium,uranyl and zinc ions with N-oxides of 4-chloro-2,6-dimethylpyridine,quinoline and 4-methoxyquinaldinic acid in presence different anions were obtained and characterized by elemental and TG analyses,IR and luminescence spectra.The compounds are crystalline,hydrated or anhydrous salts with colours typical of metal ions.Thermal studies showed that in hydrated salts lattice or coordination water molecules are present.A role of different anions in the formation of various types of the complexes is presented.

  13. 77 FR 65532 - Solid Fertilizer Grade Ammonium Nitrate From the Russian Federation: Notice of Rescission of...

    Science.gov (United States)

    2012-10-29

    ... International Trade Administration Solid Fertilizer Grade Ammonium Nitrate From the Russian Federation: Notice... the antidumping duty order on solid fertilizer grade ammonium nitrate (ammonium nitrate) from the... Administrative Review: Solid Fertilizer Grade Ammonium Nitrate (Ammonium Nitrate) from the Russian...

  14. Synthesis of hydrated lutetium carbonate

    Energy Technology Data Exchange (ETDEWEB)

    Song Liu [South China Univ. of Technology, Dept. of Applied Chemistry, Guangdong (China); Rong-jun Ma [Changsha Research Institute of Minig and Metallurgy, Hunan (China)

    1997-09-01

    Crystalline lutetium carbonate was synthesized for the corresponding chloride using ammonium bicarbonate as precipitant. The chemical analyses suggest that the synthesized lutetium carbonate is a hydrated basic carbonate or oxycarbonate. The X-ray powder diffraction data are presented. The IR data for the compound show the presence of two different carbonate groups. There is no stable intermediate carbonate in the process of thermal decomposition of the lutetium carbonate. (au) 15 refs.

  15. Effectof Material Ratio on Phase Transfer Rate of Calcium Ions During Reaction between Calcium Sulfate Dihydrate and Ammonium Carbonate%二水硫酸钙与碳酸铵反应过程中物料比对钙离子相转移速率的影响

    Institute of Scientific and Technical Information of China (English)

    陈昌国; 周加贝; 夏素兰; 王子宁; 宫源; 刘仕忠

    2015-01-01

    选择二水硫酸钙晶须为研究对象,在温度、搅拌速度、料浆浓度不变的条件下,探究了二水硫酸钙与碳酸铵反应过程中物料比 n(NH 4)2 CO 3:nCaSO 4∙2 H 2 O 对钙离子相转移速率的影响。结果表明,物料比在1.05∶1~1.4∶1之间时,生成的碳酸钙沉淀于溶液中,钙离子相转移是溶解-结晶过程,二水硫酸钙转化率和碳酸钙颗粒粒径均随物料比增大而增大,即相转移速率与物料比成正比。%Calcium sulfate dihydrate whiskers were applied under constant temperature,stirring speed and slurry concentration.The material ratio of n(NH 4 )2 CO 3 ∶nCaSO 4 ∙2 H 2 O was changed to study its effect on phase transfer of calcium ions during the reaction between calcium sulfate dihydrate and ammonium car-bonate.The result showed that calcium carbonate crystals were precipitate in solution as the material ratio between 1.05∶1 and 1.4∶1,so corresponding mechanism of calcium ions phase transfer was dissolution-precipitation.It could found that both the conversion rate of calcium sulfate dihydrate and the calcium car-bonate particles size were increased with the increasing value of materials ratio.It indicated that the phase transfer rate of calcium ions was proportional to the material ratio.

  16. Structure and spectroscopy of uranyl and thorium complexes with substituted phosphine oxide ligands

    Energy Technology Data Exchange (ETDEWEB)

    Breshears, Andrew T.; Barnes, Charles L.; Wagle, Durgesh V.; Baker, Gary A.; Walensky, Justin R. [Missouri Univ., Columbia, MO (United States). Dept. of Chemistry; Takase, Michael K. [California Institute of Technology, Pasadena, CA (United States). Beckman Institute

    2015-05-01

    Phosphine oxide ligands are important in the chemistry of the nuclear fuel cycle. We have synthesized and characterized a series of phosphine oxide ligands with polycyclic aromatic hydrocarbon (PAH) groups to enhance the spectroscopic features of uranyl, UO{sub 2}{sup 2+}, and to make detection more efficient. Complexation of OPPh{sub 2}R, R = C{sub 10}H{sub 7} (naphthyl); C{sub 14}H{sub 9} (phenanthrenyl); C{sub 14}H{sub 9} (anthracenyl); and C{sub 16}H{sub 9} (pyrenyl), to UO{sub 2}(NO{sub 3}){sub 2} afforded the eight-coordinate complexes, UO{sub 2}(NO{sub 3}){sub 2}(OPPh{sub 2}R){sub 2}. An eleven-coordinate complex, Th(NO{sub 3}){sub 4}[OPPh{sub 2}(C{sub 14}H{sub 9})]{sub 3}, C{sub 14}H{sub 9} = phenanthrenyl, was structurally characterized, and was found to be the first thorium compound isolated with three phosphine oxide ligands bound. The phosphine oxide ligands were not fluorescent but the anthracenyl-substituted ligand showed broad, red-shifted emission at approximately 50 nm relative to typical anthracene, making this ligand set a possibility for use in detection. The synthesis and spectroscopy of the uranyl and thorium complexes are presented.

  17. Structural elucidation and physicochemical properties of mononuclear Uranyl(VI) complexes incorporating dianionic units

    Science.gov (United States)

    Azam, Mohammad; Velmurugan, Gunasekaran; Wabaidur, Saikh Mohammad; Trzesowska-Kruszynska, Agata; Kruszynski, Rafal; Al-Resayes, Saud I.; Al-Othman, Zeid A.; Venuvanalingam, Ponnambalam

    2016-01-01

    Two derivatives of organouranyl mononuclear complexes [UO2(L)THF] (1) and [UO2(L)Alc] (2), where L = (2,2′-(1E,1′E)-(2,2-dimethylpropane-1,3-dyl)bis(azanylylidene, THF = Tetrahydrofuran, Alc = Alcohol), have been prepared. These complexes have been determined by elemental analyses, single crystal X-ray crystallography and various spectroscopic studies. Moreover, the structure of these complexes have also been studied by DFT and time dependent DFT measurements showing that both the complexes have distorted pentagonal bipyramidal environment around uranyl ion. TD-DFT results indicate that the complex 1 displays an intense band at 458.7 nm which is mainly associated to the uranyl centered LMCT, where complex 2 shows a band at 461.8 nm that have significant LMCT character. The bonding has been further analyzed by EDA and NBO. The photocatalytic activity of complexes 1 and 2 for the degradation of rhodamine-B (RhB) and methylene blue (MB) under the irradiation of 500W Xe lamp has been explored, and found more efficient in presence of complex 1 than complex 2 for both dyes. In addition, dye adsorption and photoluminescence properties have also been discussed for both complexes. PMID:27595801

  18. New thermo-sensitive chelating surfactants for selective solvent-free extraction of uranyl nitrate

    Energy Technology Data Exchange (ETDEWEB)

    Prevost, S.; Larpent, C.; Testard, F.; Coulombeau, H.; Baczko, K.; Berthon, L.; Desvaux, H.; Madic, C.; Zemb, T

    2004-07-01

    Functional surfactants were synthesised by grafting a chelating group (amino-acid residue) to the tip of a poly-ethoxylated nonionic surfactant chain (C{sub i}E{sub j}: C{sub i}H{sub 2i}+1(OCH{sub 2}CH{sub 2}){sub j}OH)) or in a branched position. C{sub i}E{sub j} nonionic surfactants are known to be thermo-reversible and to exhibit a clouding phenomenon associated to phase separation of micelles. The functional surfactants retain both surface-active properties, characteristic thermo-reversible behaviour and have efficient complexing properties toward uranyl. In the presence of uranyl nitrate, small micelles are formed at ambient temperature and the de-mixing leads to a separation of the target ion trapped by the functional surfactant (cloud point extraction). Those surfactants are more efficient than mixture of classical C{sub i}E{sub j} and complexing agent solubilized in the micelles. This reveals a synergistic effect of the covalent bond between the chelating group and the nonionic surfactant C{sub i}E{sub j}. This paper presents a systematic study of the extraction and aggregation properties and the influence of the nature of the ions. (authors)

  19. Extraction of nitric acid, uranyl nitrate, and bismuth nitrate from aqueous nitric acid solutions with CMPO

    Energy Technology Data Exchange (ETDEWEB)

    Spencer, B.B.

    1995-08-01

    DOE sponsored development of the transuranium extraction (TRUEX) process for removing actinides from radioactive wastes. The solvent is a mixture of CMPO and TBP. Since the extraction characteristics of CMPO are not as well understood as those of TBP, the extraction of nitric acid, uranyl nitrate, and bismuth nitrate with CMPO (dissolved in n-dodecane) were studied. Results indicate that CMPO extracts nitric acid with a 1:1 stoichiometry; equilibrium constant is 2. 660{plus_minus}0.092 at 25 C, and extraction enthalpy is -5. 46{plus_minus}0.46 kcal/mol. Slope analysis indicates that uranyl nitrate extracts with a mixed equilibria of 1:1 and 2:1 stoichiometries in nearly equal proportion. Equil. constant of the 2: 1 extraction was 1.213 {times} 10{sup 6}{plus_minus}3.56 {times} 10{sup 4} at 25 C; reaction enthalpy was -9.610{plus_minus}0.594 kcal/mol. Nitration complexation constant is 8.412{plus_minus}0.579, with an enthalpy of -10.72{plus_minus}1.87 kcal/mol. Bismuth nitrate also extracts with a mixed equilibria of (perhaps) 1:1 and 2:1 stoichiometries. A 2:1 extraction equilibrium and a nitrate complexation adequately model the data. Kinetics and enthalpies were also measured.

  20. Synthesis and Crystal Structure of Bis(nitrate)bis(dipiperidin-1-yl-methanone)uranyl(II)

    Institute of Scientific and Technical Information of China (English)

    朱利明; 何雪雁; 周俊慧; 于正风; 李宝龙; 张勇

    2004-01-01

    The new uranyl complex UO2(NO3)2[C5H10NC(O)NH10C5]2 has been synthesized and its structure was determined by single-crystal X-ray diffraction. Crystal data: C22H40N6O10U, monoclinic, space group P21/c, a = 11.151(3), b = 13.907(3), c = 10.067(2)A,β= 115.602(4)0,V = 1408.0(5) A3, Mr = 786.63, Z = 2, Dc = 1.855 g/cm3, F(000) = 772,μ = 5.827 mm-1, R = 0.0465 and wR = 0.1065 for 2916 observed reflections (I > 2σ(I)). The central uranyl ion is coordinated by six oxygen atoms, of which two are from the carbonyl groups of di-piperidin-1-yl-methanone molecules and the other four from two nitrate groups.

  1. Structural elucidation and physicochemical properties of mononuclear Uranyl(VI) complexes incorporating dianionic units

    Science.gov (United States)

    Azam, Mohammad; Velmurugan, Gunasekaran; Wabaidur, Saikh Mohammad; Trzesowska-Kruszynska, Agata; Kruszynski, Rafal; Al-Resayes, Saud I.; Al-Othman, Zeid A.; Venuvanalingam, Ponnambalam

    2016-09-01

    Two derivatives of organouranyl mononuclear complexes [UO2(L)THF] (1) and [UO2(L)Alc] (2), where L = (2,2‧-(1E,1‧E)-(2,2-dimethylpropane-1,3-dyl)bis(azanylylidene, THF = Tetrahydrofuran, Alc = Alcohol), have been prepared. These complexes have been determined by elemental analyses, single crystal X-ray crystallography and various spectroscopic studies. Moreover, the structure of these complexes have also been studied by DFT and time dependent DFT measurements showing that both the complexes have distorted pentagonal bipyramidal environment around uranyl ion. TD-DFT results indicate that the complex 1 displays an intense band at 458.7 nm which is mainly associated to the uranyl centered LMCT, where complex 2 shows a band at 461.8 nm that have significant LMCT character. The bonding has been further analyzed by EDA and NBO. The photocatalytic activity of complexes 1 and 2 for the degradation of rhodamine-B (RhB) and methylene blue (MB) under the irradiation of 500W Xe lamp has been explored, and found more efficient in presence of complex 1 than complex 2 for both dyes. In addition, dye adsorption and photoluminescence properties have also been discussed for both complexes.

  2. Synthesis and structure determination of uranyl peroxide nanospheres in the presence of organic structure directing agents

    Science.gov (United States)

    Forbes, T. Z.; Burns, P. C.

    2007-12-01

    Recently, actinyl peroxide nanoclusters containing 20, 24, 28, or 32 actinyl polyhedra have been synthesized and their structures identified with single crystal X-ray diffraction [1]. Most nanomaterials are composed of main group elements or transition metals, therefore, these actinyl nanospheres may display vastly different chemical and physical properties due to the presence of filled f-orbitals. A major goal of our research group is to create novel actinyl materials, focusing on nano- and mesoporous materials. The original nanosphere syntheses were limited to inorganic crystallization agents, such as monovalent cations. Over the last decade, the use of organic compounds and surfactants have received increased attention as structure-directing agents for the generation of novel inorganic materials. Using structure-directing organic amines we have successfully synthesized and determined the structures of uranyl nanospheres containing 40 and 50 uranyl polyhedra. The topology of the skeletal U-50 nanosphere is identical to the C50Cl10 fullerene [2]. The topographical relationship between the actinyl nanospheres and fullerene or fullerene-like material may provide additional insight into stable configurations for lower fullerenes. [1] Burns et al., Actinyl peroxide nanospheres. Angewandte Chemie, International Edition, 2005. 44(14): p. 2135. [2] Xie et al., Capturing the Labile Fullerene[50] as C50Cl10. Science, (2004) 305(5671): p. 699.

  3. Deciphering the energy landscape of the interaction uranyl-DCP with antibodies using dynamic force spectroscopy.

    Science.gov (United States)

    Teulon, Jean-Marie; Parot, Pierre; Odorico, Michael; Pellequer, Jean-Luc

    2008-11-15

    Previous studies on molecular recognition of uranyl-DCP (dicarboxy-phenanthroline chelator) compound by two distinct monoclonal antibodies (Mabs U04S and U08S) clearly showed the presence of a biphasic shape in Bell-Evans' plots and an accentuated difference in slopes at the high loading rates. To further explore the basis in the slope difference, we have performed complementary experiments using antibody PHE03S, raised against uranyl-DCP but, presenting a strong cross-reactivity toward the DCP chelator. This work allowed us to obtain a reallocation of the respective contributions of the metal ion itself and that of the chelator. Results led us to propose a 2D schematic model representing two energy barriers observed in the systems Mabs U04S- and U08S-[UO(2)-DCP] where the outer barrier characterizes the interaction between UO(2) and Mab whereas the inner barrier characterizes the interaction between DCP and Mab. Using dynamic force spectroscopy, it is thus possible to dissect molecular interactions during the unbinding between proteins and ligands.

  4. Rapid dissolution of soluble uranyl phases in arid, mine-impacted catchments near Church Rock, NM.

    Science.gov (United States)

    deLemos, Jamie L; Bostick, Benjamin C; Quicksall, Andrew N; Landis, Joshua D; George, Christine C; Slagowski, Naomi L; Rock, Tommy; Brugge, Doug; Lewis, Johnnye; Durant, John L

    2008-06-01

    We tested the hypothesis that runoff of uranium-bearing particles from mining waste disposal areas was a significant mechanism for redistribution of uranium in the northeastern part of the Upper Puerco River watershed (New Mexico). However, our results were not consistent with this hypothesis. Analysis of > 100 sediment and suspended sediment samples collected adjacent to and downstream from uranium source areas indicated that uranium levels in the majority of the samples were not elevated above background. Samples collected within 50 m of a known waste disposal site were subjected to detailed geochemical characterization. Uranium in these samples was found to be highly soluble; treatment with synthetic pore water for 24 h caused dissolution of 10--50% of total uranium in the samples. Equilibrium uranium concentrations in pore water were > 4.0 mg/L and were sustained in repeated wetting events, effectively depleting soluble uranium from the solid phase. The dissolution rate of uranium appeared to be controlled by solid-phase diffusion of uranium from within uranium-bearing mineral particles. X-ray adsorption spectroscopy indicated the presence of a soluble uranyl silicate, and possibly a uranyl phosphate. These phases were exhausted in transported sediment suggesting that uranium was readily mobilized from sediments in the Upper Puerco watershed and transported in the dissolved load. These results could have significance for uranium risk assessment as well as mining waste management and cleanup efforts.

  5. Thermo-responsive metal-chelating surfactants. Properties and use in cloud point extraction of uranyl nitrate

    Energy Technology Data Exchange (ETDEWEB)

    Prevost, S.; Coulombeau, H. [CEA, IRAMIS, SCM, LIONS, 91 - Gif-sur-Yvette (France); Univ. de Versailles St Quentin en Y. Institut Lavoisier UMR CNRS 8180 (France); Baczko, K.; Larpent, C. [Univ. de Versailles St Quentin en Y. Institut Lavoisier UMR CNRS 8180 (France); Berthon, L.; Zorz, N. [CEA/DEN/DRCP/SCPS/LCSE, 30 - Bagnols sur Ceze (France); Desvaux, H.; Testard, F. [CEA, IRAMIS, SCM, LIONS, 91 - Gif-sur-Yvette (France); Zemb, T. [ICSM, UMR 5257 CEA/CNRS/UM2/ENSCM, 30 - Bagnols sur Ceze (France)

    2009-03-15

    The properties of new thermo-responsive functional surfactants, capable of forming a metal chelate, synthesized by grafting a diamide group (amino-acid residue) to the tip hydrophilic endgroup or in a branched position to polyoxyethylene nonionic surfactants [C{sub i}E{sub j}:C{sub i}H{sub 2i+1}(OCH{sub 2}CH{sub 2}){sub j}OH)], are studied. Their use in cloud point extraction of uranyl nitrate is tested. The reversible temperature-dependent behavior of classical non-ionic surfactants associated to phase separation of micellar solutions known as clouding behavior is exploited for separation based on cation specific binding to the chelating group. The functional surfactants under investigation combine surface-active properties and characteristic thermoreversible behavior with a capacity to bind uranyl cation. The influence of the complexation on the cloud points of functional surfactants is determined. The chelating surfactants are found efficient for the cloud point extraction of uranyl nitrate at low surfactant-to-uranyl ratio. These new thermoresponsive surfactants with chelating properties hold most promise for the development of new solvent free extraction processes.

  6. Thermo-responsive Metal-chelating Surfactants: Properties and Use in Cloud Point Extraction of Uranyl Nitrate

    Energy Technology Data Exchange (ETDEWEB)

    Prevost, S.; Coulombeau, H.; Baczko, K.; Larpent, C. [Univ Versailles St Wuentin Y, Inst Lavoisier, UMR 8180, CNRS, F-78035 Versailles, (France); Prevost, S.; Coulombeau, H.; Desvaux, H.; Testard, F. [CEA, IRAMIS, SCM, LIONS, F-91191 Gif Sur Yvette, (France); Berthon, L.; Zorz, N. [CEA, DEN DRCP SCPS LCSE, F-30207 Bagnols Sur Ceze, (France); Zemb, Th. [ICSM, UMR 5257, CEA CNRS UM2 ENSCM, F-30207 Bagnols Sur Ceze, (France)

    2009-07-01

    The properties of new thermo-responsive functional surfactants, capable of forming a metal chelate, synthesized by grafting a diamide group (amino-acid residue) to the tip hydrophilic end-group or in a branched position to polyoxyethylene nonionic surfactants [CiEj: C{sub i}H{sub 2i+1}(OCH{sub 2}CH{sub 2}){sub j}OH)], are studied. Their use in cloud point extraction of uranyl nitrate is tested. The reversible temperature-dependent behavior of classical non-ionic surfactants associated to phase separation of micellar solutions known as clouding behavior is exploited for separation based on cation specific binding to the chelating group. The functional surfactants under investigation combine surface-active properties and characteristic thermo-reversible behavior with a capacity to bind uranyl cation. The influence of the complexation on the cloud points of functional surfactants is determined. The chelating surfactants are found efficient for the cloud point extraction of uranyl nitrate at low surfactant-to-uranyl ratio. These new thermo-responsive surfactants with chelating properties hold most promise for the development of new solvent free extraction processes. (authors)

  7. A New Form of Triple-Stranded Helicate Found in Uranyl Complexes of Aliphatic α,ω-Dicarboxylates.

    Science.gov (United States)

    Thuéry, Pierre; Harrowfield, Jack

    2015-11-16

    The reaction of uranyl ions with azelaic or dodecanedioic acids under solvohydrothermal conditions leads to crystallization of anionic dinuclear cage compounds with [M(bipy/phen)3](2+) counterions (M = 3d-block cation), while the smaller suberic acid yields heterometallic metallacycles. Complexes with the longer aliphatic chains are the first triple-stranded helicates reported in actinide chemistry.

  8. Treatment of uranyl nitrate and flouride solutions; Tratamiento de soluciones que contienen nitrato de uranilo y fluoruros

    Energy Technology Data Exchange (ETDEWEB)

    Rodrigo Otero, A.; Rodrigo Vilaseca, F.; Morales Calvo, G.

    1977-07-01

    A theoretical study on the fluoride complexes contained in uranyl and aluminium solutions has been carried out. Likewise concentration limits and Duhring diagrams for those solutions have been experimentally established. As a result, the optimum operation conditions for concentration by evaporation in the treatment plant, have been deduced. (Author) 12 refs.

  9. Synthesis of thermally stable extra-large pore crystalline materials: a uranyl germanate with 12-ring channels.

    Science.gov (United States)

    Lin, Chia-Hui; Chiang, Ray-Kuang; Lii, Kwang-Hwa

    2009-02-18

    A thermally stable extra-large pore uranyl germanate is synthesized under high-temperature, high-pressure hydrothermal conditions at 585 degrees C and 150 MPa. The structure contains U(6+)O(6) tetragonal bipyramids which are interconnected by digermanate groups to form a 3D framework with 12-ring pore openings.

  10. Natural Nitrogen—15 Abundance of Ammonium Nitrogen and Fixed Ammonium in Soils

    Institute of Scientific and Technical Information of China (English)

    SHISHU-LIAN; XINGGUANG-XI; 等

    1992-01-01

    The present article deals with the natural nitrogen-15 abundance of ammonium nitrogen and fixed ammonium in different soils.Variations in the natural 15N abundance of ammonium nitrogen mineralized in soils under anaerobic incubation condition were related to soil pH.The δ 15N of mineralizable N in acid soils was lower but that in neutral and calcareous soils was higher compared with the δ 15N of total N in the soils.A variation tendence was also found in the δ 15N of amino-acid N in the hydrolysates of soils.The natural 15N abundance of fixed ammonium was higher than that of total N in most surface soils and other soil horizons,indicating that the increase of δ 15N in the soil borizons beneath subsurface horizon of some forest soils and acid paddy soils was related to the higher δ 15N value of fixed ammonium in the soil.

  11. Calcium sulphate in ammonium sulphate solution

    Science.gov (United States)

    Sullivan, E.C.

    1905-01-01

    Calcium sulphate, at 25?? C., is two-thirds as soluble in dilute (o.i mol per liter) and twice as soluble in concentrated (3 mois per liter) ammonium sulphate solution as in water. The specific electric conductivity of concentrated ammonium sulphate solutions is lessened by saturating with calcium sulphate. Assuming that dissociation of ammonium sulphate takes place into 2NH4?? and SO4" and of calcium sulphate into Ca and SO4" only, and that the conductivity is a measure of such dissociation, the solubility of calcium sulphate in dilute ammonium sulphate solutions is greater than required by the mass-law. The conductivity of the dilute mixtures may be accurately calculated by means of Arrhenius' principle of isohydric solutions. In the data obtained in these calculations, the concentration of non-dissociated calcium sulphate decreases with increasing ammonium sulphate. The work as a whole is additional evidence of the fact that we are not yet in possession of all the factors necessary for reconciling the mass-law to the behavior of electrolytes. The measurements above described were made in the chemical laboratory of the University of Michigan.

  12. Reduction in Ammonium Ions in Sludge Liquor

    Directory of Open Access Journals (Sweden)

    Eglė Šlajūtė

    2013-12-01

    Full Text Available Liquor rejected from the centrifugation of the digested sludge can contain the concentrations of ammonium ions up to 1750 mg/L. These loads are usually returned to the intake of wastewater treatment plants (WWTP without additional treatment and can have a negative impact on biological wastewater and/or sludge treatment processes, e.g. phosphorus and nitrogen removal. This article deals with the use of naturally obtained sorbent, zeolite, in batch and column test procedure for removing ammonium from the rejected liquor. This research study was carried out using different sizes of zeolite particles: 0.8–1.6 mm and 1.6–2.5 mm. The highest efficiency of ammonium removal (up to 98 % was achieved by applying the zeolite particles of 0.8–1.6 mm.Article in Lithuanian

  13. 77 FR 50613 - Didecyl Dimethyl Ammonium Carbonate and Didecyl Dimethyl Ammonium Bicarbonate; Exemption From the...

    Science.gov (United States)

    2012-08-22

    ... irritating to the eye and skin, with moderate acute toxicity by oral, dermal, and inhalation routes of... From the Federal Register Online via the Government Publishing Office ENVIRONMENTAL PROTECTION... and Drug Administration (FDA) methodologies for utensils and the Indirect Dietary Residential...

  14. On the evaporation of ammonium sulfate solution

    Energy Technology Data Exchange (ETDEWEB)

    Drisdell, Walter S.; Saykally, Richard J.; Cohen, Ronald C.

    2009-07-16

    Aqueous evaporation and condensation kinetics are poorly understood, and uncertainties in their rates affect predictions of cloud behavior and therefore climate. We measured the cooling rate of 3 M ammonium sulfate droplets undergoing free evaporation via Raman thermometry. Analysis of the measurements yields a value of 0.58 {+-} 0.05 for the evaporation coefficient, identical to that previously determined for pure water. These results imply that subsaturated aqueous ammonium sulfate, which is the most abundant inorganic component of atmospheric aerosol, does not affect the vapor-liquid exchange mechanism for cloud droplets, despite reducing the saturation vapor pressure of water significantly.

  15. Ammonium Acetate Enhances the Attractiveness of a Variety of Protein-Based Baits to Female Ceratitis capitata (Diptera: Tephritidae).

    Science.gov (United States)

    Piñero, Jaime C; Souder, Steven K; Smith, Trevor R; Fox, Abbie J; Vargas, Roger I

    2015-04-01

    Ammonia and its derivatives are used by female fruit flies (Diptera: Tephritidae) as volatile cues to locate protein-rich food needed to produce their eggs. This need for external protein sources has led to the development of behaviorally based control strategies such as food-based lures and insecticidal baits targeting pestiferous fruit fly species. In field cage studies conducted in Hawaii, we examined the behavioral response of laboratory-reared male and female Mediterranean fruit fly, Ceratitis capitata (Wiedemann), to seven commercially available protein baits and to beer waste, a relatively inexpensive and readily available substance. Each material was tested alone or in combination with either ammonium acetate or ammonium carbonate. For the majority of baits evaluated, the presence of ammonium acetate, but not ammonium carbonate, elicited a significantly greater level of response of female C. capitata compared with the protein baits alone. The addition of ammonium acetate to selected baits increased bait attractiveness to a level comparable with that elicited by the most widely used spinosad-based protein bait, GF-120. Our findings indicate that the addition of ammonium acetate to commercially available proteinaceous baits and to beer waste can greatly improve their attractiveness to C. capitata, potentially increasing the bait's effectiveness for fruit fly monitoring and suppression.

  16. A novel heterotrophic nitrifying and aerobic denitrifying bacterium, Zobellella taiwanensis DN-7, can remove high-strength ammonium.

    Science.gov (United States)

    Lei, Yu; Wang, Yangqing; Liu, Hongjie; Xi, Chuanwu; Song, Liyan

    2016-05-01

    A novel heterotrophic bacterium capable of heterotrophic nitrification and aerobic denitrification was isolated from ammonium contaminated landfill leachate and physiochemical and phylogenetically identified as Zobellella taiwanensis DN-7. DN-7 converted nitrate, nitrate, and ammonium to N2 as the primary end product. Single factor experiments suggested that the optimal conditions for ammonium removal were trisodium citrate as carbon source, C/N ratio 8, pH 8.0-10.0, salinity less than 3 %, temperature 30 °C, and rotation speed more than 150 rpm. Specifically, DN-7 could remove 1000.0 and 2000.0 mg/L NH4 (+)-N completely within 96 and 216 h, with maximum removal rates of 19.6 and 17.3 mg L(-1) h(-1), respectively. These results demonstrated that DN-7 is a promising candidate for application of high-strength ammonium wastewater treatments.

  17. Manufacture of ammonium sulfate fertilizer from gypsum-rich byproduct of flue gas desulfurization - A prefeasibility cost estimate

    Science.gov (United States)

    Chou, I.-Ming; Rostam-Abadi, M.; Lytle, J.M.; Achorn, F.P.

    1996-01-01

    Costs for constructing and operating a conceptual plant based on a proposed process that converts flue gas desulfurization (FGD)-gypsum to ammonium sulfate fertilizer has been calculated and used to estimate a market price for the product. The average market price of granular ammonium sulfate ($138/ton) exceeds the rough estimated cost of ammonium sulfate from the proposed process ($111/ ton), by 25 percent, if granular size ammonium sulfate crystals of 1.2 to 3.3 millimeters in diameters can be produced by the proposed process. However, there was at least ??30% margin in the cost estimate calculations. The additional costs for compaction, if needed to create granules of the required size, would make the process uneconomical unless considerable efficiency gains are achieved to balance the additional costs. This study suggests the need both to refine the crystallization process and to find potential markets for the calcium carbonate produced by the process.

  18. Analysis of uranyl in solution through the formation of luminescent complexes; Analisis de uranilo en solucion mediante la formacion de complejos luminiscentes

    Energy Technology Data Exchange (ETDEWEB)

    Garcia G, N.; Ordonez R, E.; Barrera D, C.E. [ININ, 52750 La Marquesa, Estado de Mexico (Mexico)

    2008-07-01

    The luminescence is one of the techniques used to determine the speciation of those complex that forms the uranyl in the solid-liquid interphase of distinct zirconium phosphates, also has the advantage that it allows to carry out its quantification at mid of high ion forces, because it has been demonstrated that this detection technique and quantification is reliable and sufficiently quick in the obtaining of results. For it that in this work, the quantification of the uranyl is presented by means of a luminescent complex with the aim of phosphates that avoid the fluorescence signal extinction, then the uranyl ion is very sensitive to the medium that contains it (pH, ion force, concentration, etc.) for what was necessary to establish the analysis conditions of the uranyl ion without signal lost, in inferior concentrations to 1X10{sup -3} M at mid of sodium perchlorate 0.5 M. (Author)

  19. Effects of Aromatic Ammoniums on Methyl Ammonium Lead Iodide Hybrid Perovskite Materials

    Directory of Open Access Journals (Sweden)

    Jianli Yang

    2017-01-01

    Full Text Available The introduction of bulky ammoniums into methyl ammonium lead iodide hybrid perovskites (MAPbI3 has emerged as a promising strategy to improve the properties of these materials. In the present work, we studied the effects of several aromatic ammoniums onto the structural, electronic, and optical properties of MAPbI3. Although powder XRD data suggest that the bulky cations are not involved in the bulk phase of the MAPbI3, a surprisingly large effect of the bulky cations onto the photoluminescence properties was observed.

  20. Incorporation of Np(V) and U(VI) in Carbonate and Sulfate Minerals Crystallized from Aqueous Solution

    Energy Technology Data Exchange (ETDEWEB)

    Balboni, Enrica; Morrison, Jessica M.; Wang, Zheming; Engelhard, Mark H.; Burns, Peter C.

    2015-02-15

    The neptunyl Np(V)O2 + and uranyl U(VI)O2 2+ ions are soluble in groundwater, although their interaction with minerals in the subsurface may impact their mobility. One mechanism for the immobilization of actinyl ions in the subsurface is coprecipitation in low-temperature minerals that form naturally, or that are induced to form as part of a remediation strategy. Important differences in the crystal-chemical behavior of the Np(V) neptunyl and U(VI) uranyl ions suggest their behavior towards incorporation into growing crystals may differ significantly. Using a selection of low temperature minerals synthesized in aqueous systems under ambient conditions, this study examines the factors that impact the structural incorporation of the Np(V) neptunyl and U(VI) uranyl ions in carbonate and sulfate minerals.

  1. MCNP-DSP calculations of measurements with uranyl nitrate solution system

    Energy Technology Data Exchange (ETDEWEB)

    Valentine, T.E. [Oak Ridge National Lab., TN (United States)

    1998-09-01

    The {sup 252}Cf-source-driven noise analysis method has been used to determine the subcriticality of various configurations of fissile materials. In the past, the application of this method was limited because point-kinetics models had to be used to interpret the data; however, with the development of the Monte Carlo code MCNP-DSP, the measurements can be analyzed using the more general Monte Carlo models. The results of the Monte carlo calculations will be dependent on the ability to model the experiment accurately and on the nuclear data used to perform the calculations. This paper presents a comparison of the measured and calculated ratio of spectral densities for a subset of measurements performed with a uranyl nitrate solution tank filled to various heights. The results presented are for calculations that were performed with both ENDF/B-IV and ENDF/B-V cross-section data sets.

  2. Review of Ammonium Dinitramide Toxicity Studies

    Science.gov (United States)

    2011-01-01

    reproductive toxicant in rats, causing implantation failure in early gestation; follow-on studies implied that ADN is embryotoxic . EPR studies indicated that...mutagenic. 15. SUBJECT TERMS Ammonium dinitramide, ADN, toxicity, reproductive, embryotoxic , genotoxicity 16. SECURITY CLASSIFICATION OF: U 17...reproductive studies, reproduction and fertility, pre-implantation and post-implantation studies, implied that ADN is embryotoxic . A mouse embryo

  3. Detonation characteristics of ammonium nitrate products

    NARCIS (Netherlands)

    Kersten, R.J.A.; Hengel, E.I.V. van den; Steen, A.C. van der

    2006-01-01

    The detonation properties of ammonium nitrate (AN) products depend on many factors and are therefore, despite the large amount of information on this topic, difficult to assess. In order to further improve the understanding of the safety properties of AN, the European Fertilizer Manufacturers Associ

  4. Topaz concentrate desiliconization with ammonium bifluoride

    OpenAIRE

    Andreev, V. A.; Buynovskiy, A. S.; Andreev, Artyom Andreevich; Dyachenko, Alexander Nikolaevich

    2007-01-01

    Fluoridizing agent for the process of topaz concentrate desiliconization has been selected, topaz thermodynamic potentials have been appraised, thermodynamic probabilities of fluorination reaction of topaz concentrate main constituents have been calculated. The results of studying the concentrate desiliconization process with ammonium bifluoride by the methods of thermogravimetry, RFA, microphotography are presented

  5. Comprehensive analysis of the renal transcriptional response to acute uranyl nitrate exposure

    Directory of Open Access Journals (Sweden)

    Argiles Angel

    2006-01-01

    Full Text Available Abstract Background Chemical and radiological toxicities related to uranium acute exposure have been widely studied in nuclear fuel workers and military personnel. It is well known that uranyl nitrate induces acute renal failure (ARF. However, the mechanisms of this metal-induced injury are not well defined at the molecular level. Results Renal function and histology were assessed in mice receiving uranyl nitrate (UN(+ and controls (UN(-. To identify the genomic response to uranium exposure, serial analysis gene expression (SAGE of the kidney was performed in both groups. Over 43,000 mRNA SAGE tags were sequenced. A selection of the differentially expressed transcripts was confirmed by real-time quantitative PCR and Western blotting. UN(+ animals developed renal failure and displayed the characteristic histological lesions of UN nephropathy. Of the >14,500 unique tags identified in both libraries, 224 had a modified expression level; they are known to participate in inflammation, ion transport, signal transduction, oxidative stress, apoptosis, metabolism, and catabolism. Several genes that were identified had not previously been evaluated within the context of toxic ARF such as translationally controlled tumor protein, insulin like growth factor binding protein 7 and ribosomal protein S29, all apoptosis related genes. Conclusion We report a comprehensive description of the UN induced modifications in gene expression levels, including the identification of genes previously unrelated to ARF. The study of these genes and the metabolisms they control should improve our understanding of toxic ARF and enlighten on the molecular targets for potential therapeutic interventions.

  6. Potential remediation approach for uranium-contaminated groundwaters through potassium uranyl vanadate precipitation

    Energy Technology Data Exchange (ETDEWEB)

    Tokunaga, T.K.; Kim, Y.; Wan, J.

    2009-06-01

    Methods for remediating groundwaters contaminated with uranium (U) through precipitation under oxidizing conditions are needed because bioreduction-based approaches require indefinite supply of electron donor. Although strategies based on precipitation of some phosphate minerals within the (meta)autunite group have been considered for this purpose, thermodynamic calculations for K- and Ca-uranyl phopsphates, meta-ankoleite and autunite, predict that U concentrations will exceed the Maximum Contaminant Level (MCL = 0.13 {micro}M for U) at any pH and pCO{sub 2}, unless phosphate is maintained at much higher concentrations than the sub-{micro}M levels typically found in groundwaters. We hypothesized that potassium uranyl vanadate will control U(VI) concentrations below regulatory levels in slightly acidic to neutral solutions based on thermodynamic data available for carnotite, K{sub 2}(UO{sub 2}){sub 2}V{sub 2}O8. The calculations indicate that maintaining U concentrations below the MCL through precipitation of carnotite will be sustainable in some oxidizing waters having pH in the range of 5.5 to 7, even when dissolution of this solid phase becomes the sole supply of sub-{micro}M levels of V. Batch experiments were conducted in solutions at pH 6.0 and 7.8, chosen because of their very different predicted extents of U(VI) removal. Conditions were identified where U concentrations dropped below its MCL within 1 to 5 days of contact with oxidizing solutions containing 0.2 to 10 mM K, and 0.1 to 20 {micro}M V(V). This method may also have application in extracting (mining) U and V from groundwaters where they both occur at elevated concentrations.

  7. A facile synthesis of ω-aminoalkyl ammonium hydrogen phosphates

    Institute of Scientific and Technical Information of China (English)

    Wei Bo Kong; Xiao Yong Zhou; Yang Yang; Xing Yi Xie

    2012-01-01

    A series of ω-aminoalkyl ammonium hydrogen phosphates were synthesized through a simple and efficient three-step method.The starting materials,ω-aminoalkyl alcohols (AC-n,with carbon number n =3,4,5,6),were amino-protected with 9-fluorenylmethyl chloroformate (Fmoc-Cl),followed by phosphorylation with POCl3 and deprotection in piperidine/DMF The structures of each intermediate and final product were confirmed by 1H NMR,FTIR and mass spectrum.The yield of each step was about 77-92%,with a total yield higher than 56%.This new method was superior in low-cost raw materials,mild reaction temperatures (0-25 ℃) and easy purification methods.

  8. Surface modified magnetic Fe{sub 3}O{sub 4} nanoparticles as a selective sorbent for solid phase extraction of uranyl ions from water samples

    Energy Technology Data Exchange (ETDEWEB)

    Sadeghi, Susan, E-mail: ssadeghi@birjand.ac.ir [Department of Chemistry, Faculty of Science, University of Birjand, P.O. Box. 97175/615, Birjand (Iran, Islamic Republic of); Azhdari, Hoda [Department of Chemistry, Faculty of Science, University of Birjand, P.O. Box. 97175/615, Birjand (Iran, Islamic Republic of); Arabi, Hadi [Magnetism and Superconducting Research Lab, Department of Physics, Faculty of Science, University of Birjand, P.O. Box. 97175/615, Birjand (Iran, Islamic Republic of); Moghaddam, Ali Zeraatkar [Department of Chemistry, Faculty of Science, University of Birjand, P.O. Box. 97175/615, Birjand (Iran, Islamic Republic of)

    2012-05-15

    Highlights: Black-Right-Pointing-Pointer A new sorbent based on functionalized magnetite nanoparticles with quercetin is reported. Black-Right-Pointing-Pointer The quercetin based magnetic nanoparticles could be used as a sorbent to remove toxic uranyl ions from water samples. Black-Right-Pointing-Pointer The sorbent provides a rapidly and easy separation of uranyl ions only by using a permanent magnet. Black-Right-Pointing-Pointer This technique is considered more efficient separation compared to conventional filtering or centrifuging methods for the removing of the sorbent. - Abstract: In this study, silica-coated magnetic nanoparticles modified with quercetin were synthesized by a sol-gel method. These magnetic nanoparticles were assessed as a new solid phase sorbent for extraction of uranyl ions from aqueous solutions. The crystal and chemical structures and magnetic property of the new sorbent were characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM), Fourier transform infrared spectrophotometer (FT-IR), and vibration sample magnetometer (VSM). The experimental parameters affecting the extraction efficiency of uranyl ions from aqueous solutions using the synthesized sorbent were optimized by means of the response surface methodology. The adsorption equilibrium of uranyl ions onto the sorbent was explained by Langmuir isotherm and maximum monolayer adsorption capacity was found 12.33 mg/g. The synthesized sorbent was applied to extraction of uranyl ions from different water samples.

  9. Effect of the temperature and oxalic acid in the uranyl sorption in zircon; Efecto de la temperatura y acido oxalico en la sorcion de uranilo en circon

    Energy Technology Data Exchange (ETDEWEB)

    Ordonez R, E.; Almazan T, M. G.; Garcia G, N. [ININ, Departamento de Quimica, Carretera Mexico-Toluca s/n, 52750 Ocoyoacac, Estado de Mexico (Mexico); Hernandez O, R., E-mail: eduardo.ordonez@inin.gob.mx [Instituto Tecnologico de Veracruz, Ingenieria Quimica, Miguel Angel de Quevedo No. 2779, 91860 Veracruz (Mexico)

    2012-10-15

    In this work the results of the temperature effect study are presented on uranyl solutions adsorbed on zirconium silicate (ZrSiO{sub 4}) and also on the compounds formed in surface with oxalic acid. The adsorption isotherms of uranyl on hydrated zircon with NaClO{sub 4} 0.5 M, show an increase of the uranyl sorption efficiency when increasing the temperature from 20 to 4 C with a sudden descent in this efficiency when changing the temperature at 60 C. The uranyl sorption efficiency increases to hydrate the zircon with a solution of oxalic acid 0.1 M, maintaining the same tendency regarding to the temperatures of the sorption in medium NaClO{sub 4} 0.5 M. The complex formation in the zircon surface with organic acids of low molecular weight increases the fixation of the uranyl in solution due to the formation of ternary systems, in the order Zircon/A. Organic/Uranyl, without altering their response to the temperature. (Author)

  10. Sorption of uranyl(VI) cations on suspended silicate: effects of N-donor ligands, carboxylic acids, organic cosolvents, and metal ions

    Energy Technology Data Exchange (ETDEWEB)

    Pathak, P.N.; Choppin, G.R. [Florida State Univ., Tallahassee, FL (United States). Dept. of Chemistry and Biochemistry

    2007-07-01

    Sorption of uranyl ion, UO{sub 2}{sup 2+}, on silicate particles (3.00g/L) was studied in sodium perchlorate solution as a function of pcH and ionic strength at 298 K. The effects of different ligands (e.g., N-donors, carboxylic acids) on the uranyl sorption were investigated. At I = 0.20 M (NaClO{sub 4}), uranyl sorption on silicate increased from ca. 6% (pcH 3.0) to ca. 99% (at pcH 6.5), above which a small decrease was observed. A synergistic enhancement in uranyl sorption was observed in the presence of N-donor ligands such as 1,10-phenanthroline and ethylenediamine in the pcH range 3 to 4.5 as compared to that in the absence of ligands. Carboxylic acids inhibited the sorption in the order: citric acid > malonic acid > nitrilotriacetic acid > iminodiacetic acid > sulfosalicylic acid > succinic acid > glycolic acid. The presence of organic cosolvents such as dimethylsulfoxide, glycerol and tetrahydrofuran had no significant influence on the uranyl sorption profile. Uranyl sorption decreased marginally in the presence of 1.00 x 10{sup -3} M Eu(III). (orig.)

  11. 21 CFR 184.1141b - Ammonium phosphate, dibasic.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 3 2010-04-01 2009-04-01 true Ammonium phosphate, dibasic. 184.1141b Section 184... Listing of Specific Substances Affirmed as GRAS § 184.1141b Ammonium phosphate, dibasic. (a) Ammonium phosphate, dibasic ((NH4)2HPO4, CAS Reg. No. 7783-28-0) is manufactured by reacting ammonia with...

  12. 21 CFR 172.165 - Quaternary ammonium chloride combination.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 3 2010-04-01 2009-04-01 true Quaternary ammonium chloride combination. 172.165... HUMAN CONSUMPTION Food Preservatives § 172.165 Quaternary ammonium chloride combination. The food additive, quaternary ammonium chloride combination, may be safely used in food in accordance with...

  13. 78 FR 32690 - Certain Ammonium Nitrate From Ukraine

    Science.gov (United States)

    2013-05-31

    ... COMMISSION Certain Ammonium Nitrate From Ukraine Determination On the basis of the record \\1\\ developed in... antidumping duty order on certain ammonium nitrate from Ukraine would be likely to lead to continuation or... Publication 4396 (May 2013), entitled Certain Ammonium Nitrate from Ukraine: Investigation No....

  14. 21 CFR 184.1296 - Ferric ammonium citrate.

    Science.gov (United States)

    2010-04-01

    ... citrate (iron (III) ammonium citrate) is prepared by the reaction of ferric hydroxide with citric acid, followed by treatment with ammonium hydroxide, evaporating, and drying. The resulting product occurs in two forms depending on the stoichiometry of the initial reactants. (1) Ferric ammonium citrate (iron...

  15. Mechanistic study of the interaction of uranyl ions with zirconium oxide and zirconium silicate; Etude mecanistique de l'interaction des ions uranyle avec l'oxyde et le silicate de zirconium

    Energy Technology Data Exchange (ETDEWEB)

    Lomenech, C

    2002-04-01

    This work deals with structural and thermodynamic studies of the sorption of uranyl species on zircon and zirconia. After determination of the specific areas, of the pH of the isoelectric points, and of the sorption site numbers, thermodynamic data were obtained using alpha spectrometry, for different uranyl concentrations, different background electrolytes (NaClO{sub 4} or KNO{sub 3}) and different ionic strengths. The structural identification of the surface complexes and sorption sites was carried out using several spectroscopies: XPS spectroscopy allowed a determination of the nature of the sorption sites ({identical_to}Zr-O- on zirconia and {identical_to}Si-O- on zircon). Whereas fluorescence decay measurements gave the number of surface species, the combined use of XPS spectroscopy and laser spectro-fluorimetry enabled us to correlate differences in bonding energies and emission wavelengths with differences in the nature of the background electrolyte or in the pH of sorption; DRIFT spectroscopy was a powerful tool for the determination of the presence of sorbed uranyl nitrate species. EXAFS results clearly showed a splitting of the equatorial oxygen atoms in two shells, corresponding to a polydentate, inner-sphere complex. EXAFS results also indicated strong similarities between dry samples and in situ experiments, which confirms the validity of all the spectroscopic measurements. Macroscopic thermodynamic data were then modeled using a surface complexation model (2 pK and constant capacitance models), the results of the structural study being used as constraints for the simulation code FITEQL. (author)

  16. Structural determination of some uranyl compounds by vibrational spectroscopy; Determinacion estructural de algunos compuestos de uranilo por espectroscopia vibracional

    Energy Technology Data Exchange (ETDEWEB)

    Rodriguez S, A.; Martinez Q, E

    1990-07-15

    The vibrational spectra of different uranyl compounds has been studied and of it spectral information has been used the fundamental asymmetric vibrational frequency, to determine the length and constant bond force U=O by means of the combination of the concept of absorbed energy and the mathematical expression of Badger modified by Jones. It is intended a factor that simplifies the mathematical treatment and the results are compared with the values obtained for other methods. (Author)

  17. Role of aqueous sulfide and sulfate-reducing bacteria in the kinetics and mechanisms of the reduction of uranyl ion

    Energy Technology Data Exchange (ETDEWEB)

    Mohagheghi, A.

    1985-01-01

    Formation of sedimentary rock-hosted uranium ore deposits is thought to have resulted from the reduction by aqueous sulfide species of relatively soluble uranyl ion (U(VI)) to insoluble uranium(IV) oxides and silicates. The origin of this H/sub 2/S in such deposits can be either biogenic or abiogenic. Therefore, the kinetics and mechanism of uranyl ion reduction by aqueous sulfide, and the effect of several key variables on the reduction process in non-bacterial (sterile) systems was studied. The role of both pure and mixed cultures of sulfate-reducing bacteria on the reduction process was also investigated. In sterile systems the reduction reaction generally occurred by a two step reaction sequence. Uranium(V) (as UO/sub 2//sup +/) and U(IV) (as UO/sub 2/ the mineral uraninite) were the intermediate and final products, respectively. The initial concentration of uranyl ion required for reaction initiation had a minimum value of 0.8 ppm at pH 7, and was higher at pH values less than or greater than 7. An induction period was observed in all experiments. No reduction was observed after 8 hours at pH 8. Although increasing ionic strength increased the length of the induction period, it also increased the rate of the reduction of UO/sub 2//sup +/ in the second step. No reaction was observed under any experimental conditions with initial UO/sub 2//sup 2 +/ concentration less than 0.1 ppm, which is thought to be typical for ore forming solutions. However, by absorbing uranyl ion onto kaolinite, the reduction by H/sub 2/S occurred at lower UO/sub 2//sup 2 +/ concentrations (approx. 0.1 ppm) in that in the homogeneous system. Thus, adsorption may play a significant role in the reduction and therefore in the formation of ore deposits.

  18. Ammonium excretion and oxygen respiration of tropical copepods and euphausiids exposed to oxygen minimum zone conditions

    Directory of Open Access Journals (Sweden)

    R. Kiko

    2015-10-01

    Full Text Available Calanoid copepods and euphausiids are key components of marine zooplankton communities worldwide. Most euphausiids and several copepod species perform diel vertical migrations (DVMs that contribute to the export of particulate and dissolved matter to midwater depths. In vast areas of the global ocean, and in particular in the eastern tropical Atlantic and Pacific, the daytime distribution depth of many migrating organisms corresponds to the core of the oxygen minimum zone (OMZ. At depth, the animals experience reduced temperature and oxygen partial pressure (pO2 and an increased carbon dioxide partial pressure (pCO2 compared to their near-surface nighttime habitat. Although it is well known that low oxygen levels can inhibit respiratory activity, the respiration response of tropical copepods and euphausiids to relevant pCO2, pO2 and temperature conditions remains poorly parameterized. Further, the regulation of ammonium excretion at OMZ conditions is generally not well understood. It was recently estimated that DVM-mediated ammonium supply considerably fuels bacterial anaerobic ammonium oxidation – a major loss process for fixed nitrogen in the ocean. These estimates were based on the implicit assumption that hypoxia or anoxia in combination with hypercapnia (elevated pCO2 does not result in a downregulation of ammonium excretion. Here we show that exposure to OMZ conditions can result in strong depression of respiration and ammonium excretion in calanoid copepods and euphausiids from the Eastern Tropical North Atlantic and the Eastern Tropical South Pacific. These physiological responses need to be taken into account when estimating DVM-mediated fluxes of carbon and nitrogen into OMZs.

  19. Quaternary ammonium compounds – New occupational hazards

    Directory of Open Access Journals (Sweden)

    Agnieszka Lipińska-Ojrzanowska

    2014-10-01

    Full Text Available Quaternary ammonium compounds (QACs, quats belong to organic ionic chemical agents which display unique properties of both surfactants and disinfectants. Their wide distribution in the work environment and also in private households brings about new occupational hazards. This paper reviews reports about the health effects of QACs. QACs could play a role of sensitizers and irritants to the skin and mucous membranes. It is suspected that particular QACs can display an immunologic crossreactivity between each other and with other chemical compounds containing ammonium ion, such as muscle relaxants widely used in anesthesia. They may promote the development of airway allergy, however, the background mechanisms are still unclear and need to be further investigated. Until now, a few cases of occupational asthma induced by QACs have been described and their involvement in contact dermatitis has been documented. The possibility of anaphylaxis due to QACs cannot be excluded as well. Med Pr 2014;65(5:675–682

  20. Detonation Properties of Ammonium Dinitramide (ADN)

    Science.gov (United States)

    Wätterstam, A.; Östmark, H.; Helte, A.; Karlsson, S.

    1999-06-01

    Ammonium Dinitramide, ADN, has a potential as an oxidizer for underwater high explosives. Pure ADN has a large reaction-zone length and shows a strong non-ideal behaviour. The work presented here is an extension of previous work.(Sensitivity and Performance Characterization of Ammonium Dinitramide (ADN). Presented at 11th International Detonation Symposium, Snowmass, CO, 1998.) Experiments for determining the detonation velocity as a function of inverse charge radius and density, reaction-zone length and curvature, and the detonation pressure are presented. Measurements of pressure indicates that no, or weak von-Neumann spike exists, suggesting an immediate chemical decomposition. Experimental data are compared with predicted using thermochemical codes and ZND-theory.

  1. SHINE and Mini-SHINE Column Designs for Recovery of Mo from 140 g-U/L Uranyl Sulfate

    Energy Technology Data Exchange (ETDEWEB)

    Stepinski, Dominique C. [Argonne National Lab. (ANL), Argonne, IL (United States); Vandegrift, George F. [Argonne National Lab. (ANL), Argonne, IL (United States)

    2016-09-01

    Argonne is assisting SHINE Medical Technologies (SHINE) in their efforts to develop an accelerator-driven process that utilizes a uranyl-sulfate solution for the production of fission Mo 99. In an effort to design a Mo-recovery system for the SHINE project using low-enriched uranium (LEU), we conducted batch, breakthrough, and pulse tests to determine the Mo isotherm, mass-transfer zone (MTZ), and system parameters for a 130 g-U/L uranyl sulfate solution at pH 1 and 80°C, as described previously.1,2 The VERSE program was utilized to calculate the MTZ under various loading times and velocities. The results were then used to design Mo separation and recovery columns employing a pure titania sorbent (110-μm particles, S110, and 60 Å pore size). The plant-scale column designs assume Mo will be separated from 271 L of a 141 g-U/L uranyl sulfate solution, pH 1, containing 0.0023 mM Mo. The VERSE-designed recovery systems have been tested and verified in laboratory-scale experiments, and this approach was found to be very successful.

  2. Conversion of Uric Acid into Ammonium in Oil-Degrading Marine Microbial Communities: a Possible Role of Halomonads

    KAUST Repository

    Gertler, Christoph

    2015-04-29

    Uric acid is a promising hydrophobic nitrogen source for biostimulation of microbial activities in oil-impacted marine environments. This study investigated metabolic processes and microbial community changes in a series of microcosms using sediment from the Mediterranean and the Red Sea amended with ammonium and uric acid. Respiration, emulsification, ammonium and protein concentration measurements suggested a rapid production of ammonium from uric acid accompanied by the development of microbial communities containing hydrocarbonoclastic bacteria after 3 weeks of incubation. About 80 % of uric acid was converted to ammonium within the first few days of the experiment. Microbial population dynamics were investigated by Ribosomal Intergenic Spacer Analysis and Illumina sequencing as well as by culture-based techniques. Resulting data indicated that strains related to Halomonas spp. converted uric acid into ammonium, which stimulated growth of microbial consortia dominated by Alcanivorax spp. and Pseudomonas spp. Several strains of Halomonas spp. were isolated on uric acid as the sole carbon source showed location specificity. These results point towards a possible role of halomonads in the conversion of uric acid to ammonium utilized by hydrocarbonoclastic bacteria. © 2015 Springer Science+Business Media New York

  3. Model-based evaluation on the conversion ratio of ammonium to nitrite in a nitritation process for ammonium-rich wastewater treatment

    Institute of Scientific and Technical Information of China (English)

    LI Xiao-ming; YANG Qi; ZENG Guang-ming; A. Cornelius; K. H. Rosenwinkel; S. Kunst; D. Weichgrebe

    2004-01-01

    Modeling for nitritation process was discussed and analyzed quantlitatively for the factors that influence nitrite accumulation. The results indicated that pH, inorganic carbon source and Hydraulic Retention Time(HRT) as well as biomass concentration are the main factors that influenced the conversion ratio of ammonium to nitrite. A constant high pH can lead to a high nitritation rate and results in high conversion ratio on condition that free ammonia inhibition do not happen. In a CSTR system, without pH control, this conversion ratio can be monitored by pH variation in the reactor. The pH goes down far from the inlet level means a strongly nitrite accumulation. High concentration of alkalinity can promoted the conversion ratio by means of accelerating the nitritation rate through providing sufficient inorganic carbon source(carbon dioxide). When inorganic carbon source was depleted, the nitritation process stopped. HRT adjustment could be an efficient way to make the nitritation system run more flexible, which to some extent can meet the requirements of the fluctuant of inlet parameters such as ammonium concentration, pH, and temperature and so on. Biomass concentration is the key point, especially for a CSTR system in steady state, which was normally circumscribed by the characteristics of bacteria and may also affected by aeration mode and can be increased by prolonging the HRT on the condition of no nitrate accumulation when no recirculation available. The higher the biomass concentration is, the better the nitrite accumulation can be obtained.

  4. Engineered nano-magnetic iron oxide-urea-activated carbon nanolayer sorbent for potential removal of uranium (VI) from aqueous solution

    Science.gov (United States)

    Mahmoud, Mohamed E.; Khalifa, Mohamed A.; El Wakeel, Yasser M.; Header, Mennatllah S.; Abdel-Fattah, Tarek M.

    2017-04-01

    A novel magnetic nanosorbent was designed using chemical grafting of nano-magnetite (Nano-Fe3O4) with nanolayer of activated carbon (AC) via urea intermediate for the formation of Nano-Fe3O4-Urea-AC. Characterizing was carried out using FT-IR, SEM, HR-TEM, TGA, point of zero charge (Pzc) and surface area analysis. The designed sorbent maintained its magnetic properties and nanosized structure in the range of 8.7-14.1 nm. The surface area was identified as 389 m2/g based on the BET method. Sorption of uranyl ions from aqueous solutions was studied and evaluated in different experimental conditions. Removal of uranyl ions increased with increasing in pH value and the maximum percentage removal was established at pH 5.0. The removal and sorption processes of uranyl ions by Nano-Fe3O4-Urea-AC sorbent were studied and optimized using the batch technique. The key variables affecting removal of uranyl ions were studied including the effect of the contact time, dosage of Nano-Fe3O4-Urea-AC sorbent, reaction temperature, initial uranyl ions concentration and interfering anions and cations.

  5. One-Pot Synthesis of α-Amino Acids through Carboxylation of Ammonium Ylides with CO2 Followed by Alkyl Migration.

    Science.gov (United States)

    Mita, Tsuyoshi; Sugawara, Masumi; Sato, Yoshihiro

    2016-06-17

    A simple, yet powerful protocol for α-amino acid synthesis using carbon dioxide (CO2) was developed. α-Amino silanes could undergo four successive reactions (formation of ammonium salt, carboxylation, esterification, and 2,3- or 1,2-Stevens rearrangement) in the presence of allylic or benzylic halides under a CO2 atmosphere (1 atm). It is noteworthy that carboxylation at the position adjacent to a nitrogen atom proceeded via an ammonium ylide intermediate under mild conditions.

  6. Influence of uranyl speciation and iron oxides on uranium biogeochemical redox reactions

    Energy Technology Data Exchange (ETDEWEB)

    Stewart, B.D.; Amos, R.T.; Nico, P.S.; Fendorf, S.

    2010-03-15

    Uranium is a pollutant of concern to both human and ecosystem health. Uranium's redox state often dictates its partitioning between the aqueous- and solid-phases, and thus controls its dissolved concentration and, coupled with groundwater flow, its migration within the environment. In anaerobic environments, the more oxidized and mobile form of uranium (UO{sub 2}{sup 2+} and associated species) may be reduced, directly or indirectly, by microorganisms to U(IV) with subsequent precipitation of UO{sub 2}. However, various factors within soils and sediments may limit biological reduction of U(VI), inclusive of alterations in U(VI) speciation and competitive electron acceptors. Here we elucidate the impact of U(VI) speciation on the extent and rate of reduction with specific emphasis on speciation changes induced by dissolved Ca, and we examine the impact of Fe(III) (hydr)oxides (ferrihydrite, goethite and hematite) varying in free energies of formation on U reduction. The amount of uranium removed from solution during 100 h of incubation with S. putrefaciens was 77% with no Ca or ferrihydrite present but only 24% (with ferrihydrite) and 14% (no ferrihydrite) were removed for systems with 0.8 mM Ca. Imparting an important criterion on uranium reduction, goethite and hematite decrease the dissolved concentration of calcium through adsorption and thus tend to diminish the effect of calcium on uranium reduction. Dissimilatory reduction of Fe(III) and U(VI) can proceed through different enzyme pathways, even within a single organism, thus providing a potential second means by which Fe(III) bearing minerals may impact U(VI) reduction. We quantify rate coefficients for simultaneous dissimilatory reduction of Fe(III) and U(VI) in systems varying in Ca concentration (0 to 0.8 mM), and using a mathematical construct implemented with the reactive transport code MIN3P, we reveal the predominant influence of uranyl speciation, specifically the formation of uranyl

  7. Methane Adsorption Study Using Activated Carbon Fiber and Coal Based Activated Carbon

    Institute of Scientific and Technical Information of China (English)

    Guo Deyong; Li Fei; Liu Wenge

    2013-01-01

    Inlfuence of ammonium salt treatment and alkali treatment of the coal based activated carbon (AC) and activated carbon ifber (ACF) adsorbents on methane adsorption capacity was studied via high-pressure adsorption experiment. Sur-face functional groups and pore structure of two types of adsorbents were characterized by the application of infrared ab-sorption spectroscopy (IR) and low temperature liquid nitrogen adsorption method. The results show that both ammonium salt treatment and alkali treatment have obvious effect on changing BET, pore volume as well as pore size distribution of adsorbents; and methane adsorption capacity of the activated carbon ifber is the maximum after the ammonium salt treatment.

  8. Preparation of Carbon Nanotubes Supporting Bismuth Oxide Nanometer Particle and Its Catalysis on Thermal Decomposition of Ammonium Dinitramide%碳纳米管负载氧化铋的制备及催化二硝酰胺铵热分解的研究

    Institute of Scientific and Technical Information of China (English)

    李晓东; 杨燕; 杨荣杰

    2007-01-01

    采用微波辐射法制备了沉积于碳纳米管(CNTs)表面的氧化铋(Ri2O3)纳米粒子(Bi2O3/CNTs),用扫描电子显微镜(SEM)、光电子能谱(XPS)和X射线衍射(XRD)对制备的Bi2OO3CNTs纳米粒子进行了表征.研究了Bi2O3/CNTs纳米粒子对二硝酰胺铵(ADN)的催化热分解.结果表明,纳米Bi2O3均匀沉积在CNTs表面,平均粒径为8nm;添加3%Bi2O3/CNTs纳米粒子的ADN的初始热分解温度降低了12.8℃,热分解终止温度降低了29.3℃;NH4N(NO2)2→NH4NO3+N2O为ADN初始热分解的主导反应.%Carbon nanotubes (CNTs) supporting bismuth oxide ( Bi2O3 ) nanometer particle ( Bi2O3/CNTs) was prepared by the microwave radiation method. Bi2O3/CNTs nanometer particle was determined by means of scan electron microscopy ( SEM ), X-ray photoelectron spectroscopy ( XPS ) and X-ray diffraction (XRD). The catalytic property of Bi2O3/CNTs nanometer particle on thermal decomposition of ammonium dinitramide (AND) was investigated by TG and DSC. The results show that nanometer Bi2O3 was coated uniformly on the surface of CNTs. Average size of nanometer Bi2O3 is 8nm. Initial thermal decomposition temperature and ending thermal decomposition temperature of AND decrease 12.8℃ and 29.3℃, respectively when addition amount of Bi2O3/CNTs nanometer particle is 3%. NwH4N(NO2 )2→ NH4NO3 + N2O is dominant reaction of initial thermal decomposition of AND.

  9. Aluminium trihydroxide in combination with ammonium polyphosphate as flame retardants for unsaturated polyester resin

    Directory of Open Access Journals (Sweden)

    2009-11-01

    Full Text Available The thermal and reaction to fire characteristics of a flame retardant unsaturated polyester (UP ternary system are presented here. Thermal gravimetric analysis showed an improved thermal stability between 200–600°C with the addition of ammonium polyphosphate (APP and aluminium trihydroxide (ATH formulation. Cone calorimetry tests indicated that ATH is more efficient than calcium carbonate at delaying the ignition time, lowering the carbon monoxide yield and lowering the peak heat release (PHRR. However the addition of APP and ATH to the formulation failed to demonstrate any significant synergistic effect at reducing the PHRR.

  10. Organomontmorillonites Modified with 2-Methacryloyloxy Ethyl Alkyl Dimethyl Ammonium Bromide

    Institute of Scientific and Technical Information of China (English)

    WANG Jian-quan; WU Wen-hui

    2007-01-01

    Organomontmorillonites (organo-MMT) were synthesized by means of montmorillonites (MMT) modified with a series of 2-methacryloyloxy ethyl alkyl dimethyl ammonium bromide (MAAB) having different alkyl chain lengths as cationic surfactants through a cationic exchanging reaction, and were characterized by FTIR, TG, elemental analysis, and XRD. The microenvironment of the organic interlayer such as the orientation and arrangement of the alkyl chains of MAAB, as well as the properties of nanocomposite hydrogels, were also investigated. The amount of organic components absorbed on interlayer and the basal spacing of organo-MMT both increase with the increasing of alkyl length of MAAB. When carbon number of alkyl chain is in the region of 8 to 14, the alkyl chains between layers would adopt a disordered gauche conformation; while the carbon number is 16, an ordered all-trans conformation with a vertical orientation would be found together with the disordered gauche conformation according to the results of XRD and FTIR. Due to the difference of microenvironment of organic interlayer, the Young's moduli of the nanocomposite hydrogels increased as the alkyl chains of MAAB became longer.

  11. Uranyl(VI) nitrate salts: modeling thermodynamic properties using the binding mean spherical approximation theory and determination of "fictive" binary data.

    Science.gov (United States)

    Ruas, Alexandre; Bernard, Olivier; Caniffi, Barbara; Simonin, Jean-Pierre; Turq, Pierre; Blum, Lesser; Moisy, Philippe

    2006-02-23

    This work is aimed at a description of the thermodynamic properties of highly concentrated aqueous solutions of uranyl nitrate at 25 degrees C. A new resolution of the binding mean spherical approximation (BIMSA) theory, taking into account 1-1 and also 1-2 complex formation, is developed and used to reproduce, from a simple procedure, experimental uranyl nitrate osmotic coefficient variation with concentration. For better consistency of the theory, binary uranyl perchlorate and chloride osmotic coefficients are also calculated. Comparison of calculated and experimental values is made. The possibility of regarding the ternary system UO(2)(NO(3))(2)/HNO(3)/H(2)O as a "simple" solution (in the sense of Zdanovskii, Stokes, and Robinson) is examined from water activity and density measurements. Also, an analysis of existing uranyl nitrate binary data is proposed and compared with our obtained data. On the basis of the concept of "simple" solution, values for density and water activity for the binary system UO(2)(NO(3))(2)/H(2)O are proposed in a concentration range on which uranyl nitrate precipitates from measurements on concentrated solutions of the ternary system UO(2)(NO(3))(2)/HNO(3)/H(2)O. This new set of binary data is "fictive" in the sense that the real binary system is not stable chemically. Finally, a new, interesting predictive capability of the BIMSA theory is shown.

  12. The Influence of Linker Geometry on Uranyl Complexation by Rigidly-Linked Bis(3-hydroxy-N-methyl-pyridin-2-one)

    Energy Technology Data Exchange (ETDEWEB)

    Szigethy, Geza; Raymond, Kenneth

    2010-04-22

    A series of bis(3-hydroxy-N-methyl-pyridin-2-one) ligands was synthesized, and their respective uranyl complexes were characterized by single crystal X-ray diffraction analyses. These structures were inspected for high-energy conformations and evaluated using a series of metrics to measure co-planarity of chelating moieties with each other and the uranyl coordination plane, as well as to measure coordinative crowding about the uranyl dication. Both very short (ethyl, 3,4-thiophene and o-phenylene) and very long ({alpha},{alpha}{prime}-m-xylene and 1,8-fluorene) linkers provide optimal ligand geometries about the uranyl cation, resulting in planar, unstrained molecular arrangements. The planarity of the rigid linkers also suggests there is a degree of pre-organization for a planar coordination mode that is ideal for uranyl-selective ligand design. Comparison of intramolecular N{sub amide}-O{sub phenolate} distances and {sup 1}H NMR chemical shifts of amide protons supports earlier results that short linkers provide the optimal geometry for intramolecular hydrogen bonding.

  13. Improvement of the cloud point extraction of uranyl ions by the addition of ionic liquids.

    Science.gov (United States)

    Gao, Song; Sun, Taoxiang; Chen, Qingde; Shen, Xinghai

    2013-12-15

    The cloud point extraction (CPE) of uranyl ions by different kinds of extractants in Triton X-114 (TX-114) micellar solution was investigated upon the addition of ionic liquids (ILs) with various anions, i.e., bromide (Br(-)), tetrafluoroborate (BF4(-)), hexafluorophosphate (PF6(-)) and bis[(trifluoromethyl)sulfonyl]imide (NTf2(-)). A significant increase of the extraction efficiency was found on the addition of NTf2(-) based ILs when using neutral extractant tri-octylphosphine oxide (TOPO), and the extraction efficiency kept high at both nearly neutral and high acidity. However, the CPE with acidic extractants, e.g., bis(2-ethylhexyl) phosphoric acid (HDEHP) and 8-hydroxyquinoline (8-HQ) which are only effective at nearly neutral condition, was not improved by ILs. The results of zeta potential and (19)F NMR measurements indicated that the anion NTf2(-) penetrated into the TX-114 micelles and was enriched in the surfactant-rich phase during the CPE process. Meanwhile, NTf2(-) may act as a counterion in the CPE of UO2(2+) by TOPO. Furthermore, the addition of IL increased the separation factor of UO2(2+) and La(3+), which implied that in the micelle TOPO, NTf2(-) and NO3(-) established a soft template for UO2(2+). Therefore, the combination of CPE and IL provided a supramolecular recognition to concentrate UO2(2+) efficiently and selectively.

  14. Critical Parameters of Complex Geometries of Intersecting Cylinders Containing Uranyl Nitrate Solution

    Energy Technology Data Exchange (ETDEWEB)

    J. B. Briggs (INEEL POC); R. E. Rothe

    1999-06-14

    About three dozen previously unreported critical configurations are presented for very complex geometries filled with high concentration enriched uranyl nitrate solution. These geometries resemble a tall, thin Central Column (or trunk of a ''tree'') having long, thin arms (or ''branches'') extending up to four directions off the column. Arms are equally spaced from one another in vertical planes, and that spacing ranges from arms in contact to quite wide spacings. Both the Central Column and the many different arms are critically safe by themselves with each, alone, is filled with fissile solution; but, in combination, criticality occurs due to the interactions between arms and the column. Such neutronic interactions formed the principal focus of this study. While these results are fresh to the nuclear criticality safety industry and to those seeking novel experiments against which to validate computer codes, the experiments, themselves, are not recent. Over 100 experiments were performed at the Rocky Flats Critical Mass Laboratory between September, 1967, and February of the following year.

  15. Critical Parameters of Complex Geometry Intersecting Cylinders Containing Uranyl Nitrate Solution

    Energy Technology Data Exchange (ETDEWEB)

    Rothe, Robert Emil; Briggs, Joseph Blair

    1999-06-01

    About three dozen previously unreported critical configurations are presented for very complex geometries filled with high concentration enriched uranyl nitrate solution. These geometries resemble a tall, thin Central Column (or trunk of a "tree") having long, thin arms (or "branches") extending up to four directions off the column. Arms are equally spaced from one another in vertical planes; and that spacing ranges from arms in contact to quite wide spacings. Both the Central Column and the many different arms are critically safe by themselves when each, alone, is filled with fissile solution; but, in combination, criticality occurs due to the interactions between arms and the column. Such neutronic interactions formed the principal focus of this study. While these results are fresh to the nuclear criticality safety industry and to those seeking novel experiments against which to validate computer codes, the experiments, themselves, are not recent. Over 100 experiments were performed at the Rocky Flats Critical Mass Laboratory between September, 1967, and February of the following year.

  16. Hydrothermal Synthesis, Crystal Structure and Luminescent Properties of an Organically Templated 2-D Uranyl Sulfate

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    An organically templated 2-D uranyl sulfate, {(C2H8N)[(UO2)Cl(SO4)(H2O)]}n 1, has been hydrothermally synthesized . The crystal and molecular structures have been determined by X-ray crystallography method and spectral techniques. 1 belongs to mono- clinic, space group P21/c with a = 8.3545(17), b = 10.550(2), c = 12.370(3)(A), β = 102.64(3)°, V = 1063.9(4)(A)3, Mr = 464.64, Dc = 2.901 g/cm3, F(000) = 836, μ = 15.710 mm-1, Z = 4, the final R = 0.0286 and wR = 0.0685 for 10164 observed reflections with I > 2σ(I). 1 presents a two-dimensional layer-like structure constructed from infinite anionic [(UO2)Cl(H2O)(SO4)]- layers with [C2H8N]+ cations balancing the charge and a number of intermolecular hydrogen bonds (C-H…O and O-H…Cl) existing in the solid state. The fluorescence properties of 1 have also been discussed.

  17. Synthesis, structural investigation and kinetic studies of uranyl(VI) unsymmetrical Schiff base complexes

    Indian Academy of Sciences (India)

    Zahra Asadi; Mozaffar Asadi; Azade Zeinali; Mohammad Ranjkeshshorkaei; Karla Fejfarova; Vaclav Eigner; Michal Dusek; Aliakbar Dehnokhalaji

    2014-11-01

    Uranyl(VI) complexes with unsymmetrical N2O2 Schiff base ligands were synthesized and characterized. Their characterization was performed using UV-Vis, 1H NMR, cyclic voltammetry, single-crystal X-ray crystallography, IR, TG and C.H.N. techniques. X-ray crystallography of the complexes show that beside coordination of the tetradentate Schiff base, one DMF molecule is also coordinated. In order to investigate the effect of the substitutional groups of the Schiff base on the oxidation and reduction potentials, we used the cyclic voltammetry method. Electrochemistry of these complexes showed that the presence of electron releasing groups accelerates oxidation of the complexes. The kinetics of thermal decomposition was studied using thermal gravimetric method (TG) and Coats-Redfern equation. According to Coats-Redfern plots, the kinetics of thermal decomposition of the studied complexes is first-order in all stages. Also the kinetics and mechanism of the exchange reaction of the coordinated solvent with tributylphosphine was carried out in solution, using spectrophotometric method. As a result, the second order rate constants at four temperatures and the activation parameters were calculated showing an associative mechanism for all corresponding complexes. It was concluded that the steric and the electronic properties of the complexes influence the reaction rate significantly.

  18. Sorption of strontium on uranyl peroxide: implications for a high-level nuclear waste repository.

    Science.gov (United States)

    Sureda, Rosa; Martínez-Lladó, Xavier; Rovira, Miquel; de Pablo, Joan; Casas, Ignasi; Giménez, Javier

    2010-09-15

    Strontium-90 is considered the most important radioactive isotope in the environment and one of the most frequently occurring radionuclides in groundwaters at nuclear facilities. The uranyl peroxide studtite (UO2O2 . 4H2O) has been observed to be formed in spent nuclear fuel leaching experiments and seems to have a relatively high sorption capacity for some radionuclides. In this work, the sorption of strontium onto studtite is studied as a function of time, strontium concentration in solution and pH. The main results obtained are (a) sorption is relatively fast although slower than for cesium; (b) strontium seems to be sorbed via a monolayer coverage of the studtite surface, (c) sorption has a strong dependence on ionic strength, is negligible at acidic pH, and increases at neutral to alkaline pH (almost 100% of the strontium in solution is sorbed above pH 10). These results point to uranium secondary solid phase formation on the spent nuclear fuel as an important mechanism for strontium retention in a high-level nuclear waste repository (HLNW).

  19. A new low temperature route to uranyl borates with structural variations

    Energy Technology Data Exchange (ETDEWEB)

    Wu, Shijun [Kiel Univ. (Germany). Inst. fuer Geowissenschaften; Chinese Academy of Sciences, Guangzhou (China). Guangzhou Inst. of Geochemistry; Forschungszentrum Juelich GmbH (Germany). Inst. fuer Energie- und Klimaforschung (IEK-6); Wang, Shuao [Notre Dame Univ., IN (United States). Dept. of Civil Engineering and Geological Sciences; Notre Dame Univ., IN (United States). Dept. of Chemistry and Biochememistry; Lawrence Berkeley Lab., Berkeley, CA (United States). Actinide Chemistry Group; California Univ., Berkeley, CA (United States). Dept. of Chemistry; Polinski, Matthew J. [Notre Dame Univ., IN (United States). Dept. of Civil Engineering and Geological Sciences; Notre Dame Univ., IN (United States). Dept. of Chemistry and Biochememistry; Depmeier, Wulf [Kiel Univ. (Germany). Inst. fuer Geowissenschaften; Albrecht-Schmitt, Thomas E. [Florida State Univ., Tallahassee, FL (United States). Dept. of Chemistry and Biochemistry; Alekseev, Evgeny V. [Forschungszentrum Juelich GmbH (Germany). Inst. fuer Energie- und Klimaforschung (IEK-6); RWTH Aachen Univ. (Germany). Inst. fuer Kristallographie

    2013-10-01

    Three new uranyl borates, K(UO{sub 2})(BO{sub 3}) (1), Rb(UO{sub 2})(BO{sub 3}) (2) and Cs(UO{sub 2})(BO{sub 3}) (3) have been prepared using B{sub 2}O{sub 3} fluxes at 1000 C. 1 and 3 can also be synthesized using potassium tetraborate tetrahydrate as a molten flux at 290 C, which provides a new low temperature route to prepare actinide borates. 1 possesses an a-uranophane anion sheet topology identical to that in the previously reported compounds Li(UO{sub 2})(BO{sub 3}) and Na(UO{sub 2})(BO3). 2 and 3 display a new [UO{sub 5}]{sub 1{infinity}} anion topology with a basic building block of edge-sharing dimers comprised of (UO{sub 7}){sub 2} polyhedra. The A(UO{sub 2})(BO{sub 3}) (A = alkali metal) series shows a systematic structural evolution, which will be discussed in the main text. (orig.)

  20. Uranyl-specific binding at a functionalised interface: a chemophotonic fibre optic sensor platform.

    Science.gov (United States)

    Hayes, Neil W; Tremlett, Clare J; Melfi, Patricia J; Sessler, Jonathon D; Shaw, Andrew M

    2008-05-01

    Detection of radiological materials in the solution phase is restricted by conventional radiation-counting techniques owing to extreme attenuation. Chemical sensing of the resultant radiological species such as uranyl UO(2)(2+) is possible on the surface of a plastic or glass fibre optic. A dihydroxy isoamethryin complex is tethered to the fibre surface which has a large extinction coefficient (119 000 M(-1) cm(-1) at lambda = 439 nm) and changes colour upon binding UO(2)(2+). The spectral changes are greater on the surface than in solution and binding is specific to UO(2)(2+) with small interferences from Gd(3+). Monitoring the spectral response in three detector bands in the red, green and blue enable the optical power change to be measured with sensitivities of 1 mdB, allowing UO(2)(2+) to be detected confidently at 50-100 ppb levels. Real-time kinetic analysis enables discrimination between the target species and possible interferents.

  1. Oxo Ligand Substitution in a Cationic Uranyl Complex: Synergistic Interaction of an Electrophile and a Reductant.

    Science.gov (United States)

    Pedrick, Elizabeth A; Wu, Guang; Hayton, Trevor W

    2015-07-20

    Reaction of [U(VI)O2(dppmo)2(OTf)][OTf] (dppmo = Ph2P(O)CH2P(O)Ph2) with 4 equiv of Ph3SiOTf and 2 equiv of Cp2Co generates the U(IV) complex U(IV)(OTf)4(dppmo)2 (1), as a yellow-green crystalline solid in 83% yield, along with Ph3SiOSiPh3 and [Cp2Co][OTf]. This reaction proceeds via a U(IV) silyloxide intermediate, [U(IV)(OSiPh3)(dppmo)2(OTf)2][OTf] (2), which we have isolated and structurally characterized. Similarly, reaction of [U(VI)O2(TPPO)4][OTf]2 (TPPO = Ph3PO) with 6 equiv of Me3SiOTf and 2 equiv of Cp2Co generates the U(IV) complex, [Cp2Co][U(IV)(OTf)5(TPPO)2] (3), as a yellow-green crystalline solid in 76% yield, concomitant with formation of Me3SiOSiMe3, [Ph3POSiMe3][OTf], and [Cp2Co][OTf]. Complexes 1 and 3 have been fully characterized, including analysis by X-ray crystallography. The conversion of [U(VI)O2(dppmo)2(OTf)][OTf] and [U(VI)O2(TPPO)4][OTf]2 to complexes 1 and 3, respectively, represents rare examples of well-defined uranyl oxo ligand substitution.

  2. Stable Ammonium Bisulfate Clusters in the Atmosphere

    Science.gov (United States)

    Vehkamäki, Hanna; Napari, Ismo; Kulmala, Markku; Noppel, Madis

    2004-09-01

    Liquid drop model based equilibrium thermodynamics predicts that in the presence of even small ammonia concentrations practically all the atmospheric sulfuric acid molecules are bound to tiny, stable ammonium-bisulfate clusters. Hitherto sulfuric acid has been believed to form hydrates with water. Thermodynamic theory predicts correctly the hydrate formation observed experimentally. Results from ab initio computer simulations contradict the thermodynamic results and also the experimental findings for cluster formation in both sulfuric acid-water and ammonia-sulfuric acid-water mixtures.

  3. Ammonium nitrate fertiliser production based on biomass - environmental effects from a life cycle perspective.

    Science.gov (United States)

    Ahlgren, Serina; Baky, Andras; Bernesson, Sven; Nordberg, Ke; Norén, Olle; Hansson, Per-Anders

    2008-11-01

    Ammonium nitrate and calcium ammonium nitrate are the most commonly used straight nitrogen fertilisers in Europe, accounting for 43% of the total nitrogen used for fertilisers. They are both produced in a similar way; carbonate can be added as a last step to produce calcium ammonium nitrate. The environmental impact, fossil energy input and land use from using gasified biomass (cereal straw and short rotation willow (Salix) coppice) as feedstock in ammonium nitrate production were studied in a cradle-to-gate evaluation using life cycle assessment methodology. The global warming potential in the biomass systems was only 22-30% of the impact from conventional production using natural gas. The eutrophication potential was higher for the biomass systems due to nutrient leaching during cultivation, while the acidification was about the same in all systems. The primary fossil energy use was calculated to be 1.45 and 1.37MJ/kg nitrogen for Salix and straw, respectively, compared to 35.14MJ for natural gas. The biomass production was assumed to be self-supporting with nutrients by returning part of the ammonium nitrate produced together with the ash from the gasification. For the production of nitrogen from Salix, it was calculated that 3914kg of nitrogen can be produced every year from 1ha, after that 1.6% of the produced nitrogen has been returned to the Salix production. From wheat straw, 1615kg of nitrogen can be produced annually from 1ha, after that 0.6% of the nitrogen has been returned.

  4. Ion-pair hollow-fiber liquid-phase microextraction of the quaternary ammonium surfactant dicocodimethylammonium chloride.

    Science.gov (United States)

    Hultgren, Sofie; Larsson, Niklas; Nilsson, Bo F; Jönsson, Jan Ake

    2009-02-01

    A two-phase hollow-fiber (HF) liquid-phase microextraction (LPME) method was developed for determination of a quaternary ammonium compound surfactant, dicocodimethylammonium chloride, in aqueous samples. The porous HF was fixed on a metal rod support and was impregnated with approximately 6.6 microL of organic extractant, which was immobilized in the HF pores. Surfactant extraction was facilitated by addition of carboxylic acid to the sample forming neutral ion pairs with the quaternary ammonium compound. After extraction, the analyte was transferred from the organic extractant in the fiber pores by dissolving the 1-octanol into 100 microL methanol. The methanol extract was analyzed by liquid chromatography-mass spectrometry. The method was optimized (with optimized parameters in brackets) with regard to type of organic extractant (1-octanol), fiber length (2 cm), choice and concentration of anionic carrier (600 microg L(-1) octanoate), procedure of transfer to methanol (15-min sonication), sample volume (250 mL), extraction time (17 h), pH (10), and ionic strength (50 mM carbonate). Aspects influencing repeatability in LPME of (quaternary ammonium) surfactants are discussed. The enrichment factor achieved in 250-mL carbonate buffer was around 400. Due to matrix effects, the enrichment factors achieved when industrial process water was analyzed were 120 or about 30% of that in carbonate buffer. Detection limits of 0.3 microg L(-1) in carbonate buffer and 0.9 microg L(-1) in industrial process water were obtained. If the studied compound is seen as a model substance representing quaternary dialkylated dimethylated ammonium surfactants in general, the developed method may be applied to other quaternary ammonium surfactants.

  5. Synthesis of novel quaternary ammonium surfactants containing adamantane

    Institute of Scientific and Technical Information of China (English)

    Jian Wei Guo; Xing Zhong; Hua Zhu; Li Juan Feng; Ying De Cui

    2012-01-01

    A series of novel quaternary ammonium surfactants containing adamantane were designed and synthesized from 1-adamantanecarboxylic acid.The structures of target surfactants were confirmed by 1H NMR,elements analysis and FTIR.Surface properties of these surfactants were investigated.Due to the lipophilicity of adamantane,the critical micelle concentration (CMC) and C20 values of the synthesized quaternary ammonium surfactants are lower than that of conventional quaternary ammonium surfactants.

  6. Reassimilation of ammonium in Lotus japonicus.

    Science.gov (United States)

    Betti, Marco; García-Calderón, Margarita; Pérez-Delgado, Carmen M; Credali, Alfredo; Pal'ove-Balang, Peter; Estivill, Guillermo; Repčák, Miroslav; Vega, José M; Galván, Francisco; Márquez, Antonio J

    2014-10-01

    This review summarizes the most recent results obtained in the analysis of two important metabolic pathways involved in the release of internal sources of ammonium in the model legume Lotus japonicus: photorespiratory metabolism and asparagine breakdown mediated by aparaginase (NSE). The use of photorespiratory mutants deficient in plastidic glutamine synthetase (GS2) enabled us to investigate the transcriptomics and metabolomic changes associated with photorespiratory ammonium accumulation in this plant. The results obtained indicate the existence of a coordinate regulation of genes involved in photorespiratory metabolism. Other types of evidence illustrate the multiple interconnections existing among the photorespiratory pathway and other processes such as intermediate metabolism, nodule function, and secondary metabolism in this plant, all of which are substantially affected in GS2-deficient mutants because of the impairment of the photorespiratory cycle. Finally, the importance of asparagine metabolism in L. japonicus is highlighted because of the fact that asparagine constitutes the vast majority of the reduced nitrogen translocated between different organs of this plant. The different types of NSE enzymes and genes which are present in L. japonicus are described. There is a particular focus on the most abundant K(+)-dependent LjNSE1 isoform and how TILLING mutants were used to demonstrate by reverse genetics the importance of this particular isoform in plant growth and seed production.

  7. Ammonium nitrate: a promising rocket propellant oxidizer

    Science.gov (United States)

    Oommen; Jain

    1999-06-30

    Ammonium nitrate (AN) is extensively used in the area of fertilizers and explosives. It is present as the major component in most industrial explosives. Its use as an oxidizer in the area of propellants, however, is not as extensive as in explosive compositions or gas generators. With the growing demand for environmental friendly chlorine free propellants, many attempts have been made of late to investigate oxidizers producing innocuous combustion products. AN, unlike the widely used ammonium perchlorate, produces completely ecofriendly smokeless products. Besides, it is one of the cheapest and easily available compounds. However, its use in large rocket motors is restricted due to some of its adverse characteristics like hygroscopicity, near room temperature phase transformation involving a volume change, and low burning rate (BR) and energetics. The review is an attempt to consolidate the information available on the various issues pertaining to its use as a solid propellant oxidizer. Detailed discussions on the aspects relating to phase modifications, decomposition chemistry, and BR and energetics of AN-based propellants, are presented. To make the review more comprehensive brief descriptions of the history, manufacture, safety, physical and chemical properties and various other applications of the salt are also included. Copyright 1999 Elsevier Science B.V.

  8. POLYMER—SUPPORTED SINGLE AND MIXED AMMONIUM AND PHOSPHONIUM SALTS AS CATALYSTS FOR PHASE—TRANSFER REACTIONS

    Institute of Scientific and Technical Information of China (English)

    POPAAdrian; PARVULESCUViorica; 等

    2001-01-01

    In this study was to investigate,by phase-transfer catalysis,the activity of single and mixed ammonium and phosphonium salts grafted on a "gel-type" stryene-7% divinylbenzene copolymer in the oxidation of benzyl alcohol with hydrogen peroxide.A wide variety of catalysts with different quaternary groups and different quaternary chain length substitutents were examined.The activity of single"onium"salts increases as a consequence of the association of ammonium and phosphonium salts grafted onn the same polymeric support.The activity of polymer-supported ammonium and phosphonium salts increases with the number of carbon atoms contained in the alkyl radicals of the -onium and of the functionalization degree with phosphonium groups.

  9. POLYMER-SUPPORTED SINGLE AND MIXED AMMONIUM AND PHOSPHONIUM SALTS AS CATALYSTS FOR PHASE-TRANSFER REACTIONS

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    In this study was to investigate, by phase-transfer catalysis, the activity of single and mixed ammonium and phosphonium salts grafted on a "gel-type" styrene-7% divinylbenzene copolymer in the oxidation of benzyl alcohol with hydrogen peroxide.A wide variety of catalysts with different quaternary groups and different quaternary chain length substituents were examined.The activity of single "onium" salts increases as a consequence of the association of ammonium and phosphonium salts grafted on the same polymeric support. The activity of polymer-supported ammonium and phosphonium salts increases with the number of carbon atoms contained in the alkyl radicals of the -onium and of the functionalization degree with phosphonium groups.

  10. Determination of formation constants of uranyl(VI complexes with a hydrophilic SO3-Ph-BTP ligand, using liquid-liquid extraction

    Directory of Open Access Journals (Sweden)

    Steczek Lukasz

    2015-12-01

    Full Text Available Complex formation between uranyl ion, UO22+, and a hydrophilic anionic form of SO3-Ph-BTP4- ligand, L4-, in water was studied by liquid-liquid extraction experiments performed over a range of the ligand and HNO3 concentrations in the aqueous phase, at a constant concentration of nitrate anions at 25°C . The competition for UO22+ ions between the lipophilic TODGA extractant and the hydrophilic L4- ligand leads to the decrease in the uranyl distribution ratios, D, with an increasing L4- concentration. The model of the solvent extraction process used accounts - apart from uranyl complexation by TODGA and SO3-Ph-BTP4- - also for uranyl complexation by nitrates and for the decrease in the concentration of the free L4- ligand in the aqueous phase, due to its protonation, bonding in the uranyl complex and the distribution between the two liquid phases. The unusually strong dependence of the D values on the acidity, found in the experiment, could hardly be explained as due to L4- protonation merely. Three hypotheses were experimentally tested, striving to interpret the data in terms of additional extraction to the organic phase of ion associates of protonated TODGA cation with either partly protonated anionic L4- ligands or anionic UO22+ complexes with NO3 - or L4-. None of them has been confirmed. The analysis of the results, based on the formal correction of free ligand concentrations, points to the formation of 1 : 1 and 1 : 2 uranyl - SO3-Ph-BTP complexes in the aqueous phase. The conditional formation constant of the 1:1 complex has been determined, logßL,1 = 2.95 ± 0.15.

  11. Highly Enriched Uranyl Nitrate in Annular Tanks with Concrete Reflection: 1 x 3 Line Array of Nested Pairs of Tanks

    Energy Technology Data Exchange (ETDEWEB)

    James Cleaver; John D. Bess; Nathan Devine; Fitz Trumble

    2009-09-01

    A series of seven experiments were performed at the Rocky Flats Critical Mass Laboratory beginning in August, 1980 (References 1 and 2). Highly enriched uranyl nitrate solution was introduced into a 1-3 linear array of nested stainless steel annular tanks. The tanks were inside a concrete enclosure, with various moderator and absorber materials placed inside and/or between the tanks. These moderators and absorbers included boron-free concrete, borated concrete, borated plaster, and cadmium. Two configurations included placing bottles of highly enriched uranyl nitrate between tanks externally. Another experiment involved nested hemispheres of highly enriched uranium placed between tanks externally. These three configurations are not evaluated in this report. The experiments evaluated here are part of a series of experiments, one set of which is evaluated in HEU-SOL-THERM-033. The experiments in this and HEU-SOL-THERM-033 were performed similarly. They took place in the same room and used the same tanks, some of the same moderators and absorbers, some of the same reflector panels, and uranyl nitrate solution from the same location. There are probably additional similarities that existed that are not identified here. Thus, many of the descriptions in this report are either the same or similar to those in the HEU-SOL-THERM-033 report. Seventeen configurations (sixteen of which were critical) were performed during seven experiments; six of those experiments are evaluated here with thirteen configurations. Two configurations were identical, except for solution height, and were conducted to test repeatability. The solution heights were averaged and the two were evaluated as one configuration, which gives a total of twelve evaluated configurations. One of the seventeen configurations was subcritical. Of the twelve critical configurations evaluated, nine were judged as acceptable as benchmarks.

  12. 13C NMR and XPS characterization of anion adsorbent with quaternary ammonium groups prepared from rice straw, corn stalk and sugarcane bagasse

    Science.gov (United States)

    Cao, Wei; Wang, Zhenqian; Zeng, Qingling; Shen, Chunhua

    2016-12-01

    Despite amino groups modified crop straw has been intensively studied as new and low-cost adsorbent for removal of anionic species from water, there is still a lack of clear characterization for amino groups, especially quaternary ammonium groups in the surface of crop straw. In this study, we used 13C NMR and XPS technologies to characterize adsorbents with quaternary ammonium groups prepared from rice straw, corn stalk and sugarcane bagasse. 13C NMR spectra clearly showed the presence of quaternary ammonium groups in lignocelluloses structure of modified crop straw. The increase of nitrogen observed in XPS survey spectra also indicated the existence of quaternary ammonium group in the surface of the adsorbents. The curve fitting of high-resolution XPS N1s and C1s spectra were conducted to probe the composition of nitrogen and carbon contained groups, respectively. The results showed the proportion of quaternary ammonium group significantly increased in the prepared adsorbent's surface that was dominated by methyl/methylene, hydroxyl, quaternary ammonium, ether and carbonyl groups. This study proved that 13C NMR and XPS could be successfully utilized for characterization of quaternary ammonium modified crop straw adsorbents.

  13. Mechanism of rhythmic contractions induced by uranyl ion in the ileal longitudinal muscle of guinea-pig

    Energy Technology Data Exchange (ETDEWEB)

    Wenmei Fu; Shoeiyn Linshiau

    1985-07-17

    The uranyl ion (UO2S ) produces rhythmic contractions of the longitudinal muscle of the ileum, similar to those induced by repetitive transmural stimulation. Hexamethonium inhibited the action of UO2S , indicating a preganglionic site of action of UO2S and interneurons possibly being involved in the ACh-releasing effect of UO2S . In addition, the action of UO2S was enhanced by physostigmine but antagonized by atropine, ATP, adrenaline and morphine suggesting multiple sites of action of UO2S . The effects of BaS were studied simultaneously in order to compare them with those of UO2S . (Auth.). 25 refs.; 4 figs.

  14. Chemical controls on uranyl citrate speciation and the self-assembly of nanoscale macrocycles and sandwich complexes in aqueous solutions.

    Science.gov (United States)

    Basile, M; Unruh, D K; Gojdas, K; Flores, E; Streicher, L; Forbes, T Z

    2015-03-28

    Uranyl citrate forms trimeric species at pH > 5.5, but exact structural characteristics of these important oligomers have not previously been reported. Crystallization and structural characterization of the trimers suggests the self-assembly of the 3 : 3 and 3 : 2 U : Cit complexes into larger sandwich and macrocyclic molecules. Raman spectroscopy and ESI-MS have been utilized to investigate the relative abundance of these species in solution under varying pH and citrate concentrations. Additional dynamic light scattering experiments indicate that self-assembly of the larger molecules does occur in aqueous solution.

  15. The Structure of Ammonium D,L-Tartrate

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    The single crystals of the title compound NH4+C4H5O6- (C4H9NO6, Mr = 167.1) were obtained from a hot aqueous solution containing L-glutamine and D,L-tartaric acid in mole ratio1:1.5. The crystal belongs to monoclinic space group P21/c with a = 7.646(2), b = 7.804(2), c = 11.502(3)?, β = 102.26(2)o, V = 670.7(3)?3, Z = 4, F(000) = 352, Dc = 1.655 g.cm-3, ((MoK() = 0.16 mm-1, R = 0.035, wR = 0.094 for 1028 observed reflections (I>2((I)). The enatiomeric anions of the tartrate with both (2S,3S)- and (2R,3R)-configuration co-exist in the unit cell. The carbon skeleton assumes a coplanar arrangement with a torsion angle of 181.5o. The three- dimensional H-bonding network exists in the crystal. While tartrate groups link each other by H-bonds between carboxyl and hydroxyl groups, the ammonium cations insert between the tartrate groups to form a sandwich-like crystal structure.

  16. Unsteady growth of ammonium chloride dendrites

    Science.gov (United States)

    Martyushev, L. M.; Terentiev, P. S.; Soboleva, A. S.

    2016-02-01

    Growth of ammonium chloride dendrites from aqueous solution is experimentally investigated. The growth rate υ and the radius ρ of curvature of branches are measured as a function of the relative supersaturation Δ for steady and unsteady growth conditions. It is shown that the experimental results are quantitatively described by the dependences ρ=a/Δ+b, υ=cΔ2, where the factors for primary branches are a=(1.3±0.2)·10-7 m, b=(2.5±0.4)·10-7 m, and c=(2.2±0.3)·10-4 m/s. The factor c is found to be approximately 7 times smaller for the side branches than that for the primary branches.

  17. Efficient cellulose solvent: quaternary ammonium chlorides.

    Science.gov (United States)

    Kostag, Marc; Liebert, Tim; El Seoud, Omar A; Heinze, Thomas

    2013-10-01

    Pure quaternary tetraalkylammonium chlorides with one long alkyl chain dissolved in various organic solvents constitute a new class of cellulose solvents. The electrolytes are prepared in high yields and purity by Menshutkin quaternization, an inexpensive and easy synthesis route. The pure molten tetraalkylammonium chlorides dissolve up to 15 wt% of cellulose. Cosolvents, including N,N-dimethylacetamide (DMA), may be added in large excess, leading to a system of decreased viscosity. Contrary to the well-established solvent DMA/LiCl, cellulose dissolves in DMA/quaternary ammonium chlorides without any pretreatment. Thus, the use of the new solvent avoids some disadvantages of DMA/LiCl and ionic liquids, the most extensively employed solvents for homogeneous cellulose chemistry.

  18. Hydration Structure of the Quaternary Ammonium Cations

    KAUST Repository

    Babiaczyk, Wojtek Iwo

    2010-11-25

    Two indicators of the hydropathicity of small solutes are introduced and tested by molecular dynamics simulations. These indicators are defined as probabilities of the orientation of water molecules\\' dipoles and hydrogen bond vectors, conditional on a generalized distance from the solute suitable for arbitrarily shaped molecules. Using conditional probabilities, it is possible to distinguish features of the distributions in close proximity of the solute. These regions contain the most significant information on the hydration structure but cannot be adequately represented by using, as is usually done, joint distance-angle probability densities. Our calculations show that using our indicators a relative hydropathicity scale for the interesting test set of the quaternary ammonium cations can be roughly determined. © 2010 American Chemical Society.

  19. Structural study of the uranyl and rare earth complexation functionalized by the CMPO; Etude structurale de la complexation de l'uranyle et des ions lanthanides par des calixarenes fonctionnalises par le CMPO

    Energy Technology Data Exchange (ETDEWEB)

    Cherfa, S

    1998-12-10

    In view of reducing the volume of nuclear waste solutions, a possible way is to extract simultaneously actinide and lanthanide ions prior to their ulterior separation.. Historically, the two extractant families used for nuclear waste reprocessing are the phosphine oxides and the CMPO (Carbamoyl Methyl Phosphine Oxide). For a better understanding of the complexes formed during extraction, we undertook structural studies of the complexes formed between uranyl and lanthanide (III) ions and the two classes of ligands cited above. These studies have been performed by X-ray diffraction on single crystals. Recently, a new type of extractants of lanthanide (III) and actinide (III) ions has been developed. When the Organic macrocycle called calixarene (an oligomeric compound resulting from the poly-condensation of phenolic units) is functionalized by a CMPO ligand, the extracting power, in terms of yield and selectivity towards lightest lanthanides, is greatly enhanced compared to the one measured for the single CMPO. Our X-ray diffraction studies allowed us to characterise, in terms of stoichiometry and monodentate or bidentate coordination mode of the CMPO functions, the complexes of calix[4]arene-CMPO (with four phenolic units) with lanthanide nitrates and uranyl. These different steps of characterisation enabled us to determine the correlation between the structures of the complexes and both selectivity and exacerbation of the extracting power measured in the liquid phase. (author)

  20. 21 CFR 73.1298 - Ferric ammonium ferrocyanide.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 1 2010-04-01 2010-04-01 false Ferric ammonium ferrocyanide. 73.1298 Section 73.1298 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES GENERAL...) Identity. (1) The color additive ferric ammonium ferrocyanide is the blue pigment obtained by...

  1. Ammonium removal from landfill leachate by anodic oxidation

    Energy Technology Data Exchange (ETDEWEB)

    Cabeza, Adelaida [Department of Chemical Engineering, University of Cantabria, Avda. de los Castros s/n. 39005 Santander (Spain); Urtiaga, Ane [Department of Chemical Engineering, University of Cantabria, Avda. de los Castros s/n. 39005 Santander (Spain)]. E-mail: urtiaga@unican.es; Rivero, Maria-Jose [Department of Chemical Engineering, University of Cantabria, Avda. de los Castros s/n. 39005 Santander (Spain); Ortiz, Inmaculada [Department of Chemical Engineering, University of Cantabria, Avda. de los Castros s/n. 39005 Santander (Spain)

    2007-06-18

    The feasibility of removing ammonium from landfill leachates by electrochemical oxidation was studied. Raw leachates and biologically/physico-chemically pretreated leachates from a municipal landfill site were treated. Boron doped diamond was used as anode and stainless steel as cathode, both electrodes with an area of 70 cm{sup 2}. The effects of the applied current density (15-90 mA cm{sup -2}), the initial ammonium concentration (480-2000 mg L{sup -1}), and the initial chloride concentration were experimentally studied. Total ammonium removal was obtained after 360 min of processing and almost half of the initial ammonium nitrogen was oxidized to nitrate. On the other hand, the concentration of chloride enhanced the rate of ammonium oxidation. In addition, the amount of N-NH{sub 4} {sup +} transformed into N-NO{sub 3} {sup -} decreased when additional chloride was provided.

  2. Seasonal patterns of ammonium regeneration from size-fractionated microheterotrophs

    Science.gov (United States)

    Maguer, Jean-François; L'Helguen, Stéphane; Madec, Christian; Le Corre, Pierre

    1999-11-01

    Ammonium regeneration by size-fractionated plankton was measured for 1 year at a coastal station in the shallow well-mixed waters of the western English Channel. Rates of ammonium regeneration in the Journal of Plankton Research, 18, 355-370). Total ammonium regenerated in a year by the microheterotrophs was 15 g N m -2, equivalent to about 60% of the total nitrogen uptake. Microplankton (200-15 μm) accounted for about 50% of the regeneration measured between early spring and late summer. Percent contribution of nanoplankton to total ammonium regeneration varied considerably between the seasons, from very high (83-88%) levels in winter to very low (2-13%) levels in summer. Contribution by picoplankton (nano- and picoplankton fractions, appears to be different from that in deep well-mixed waters. Here, the relative contribution of ciliates and bacteria to ammonium regeneration shows little variation with an increase in macrozooplankton biomass.

  3. Potential contribution of planktonic components to ammonium cycling in the coastal area off central-southern Chile during non-upwelling conditions

    Science.gov (United States)

    Molina, Veronica; Morales, Carmen E.; Farías, Laura; Cornejo, Marcela; Graco, Michelle; Eissler, Yoanna; Cuevas, Luis A.

    2012-01-01

    The potential contributions of different microbial components (consumption and production, and carbon assimilation associated with photolithotrophic and chemolithoautotrophic (nitrification) metabolisms in the water column were performed. Despite low water column concentrations of ammonium in wintertime, intense ammonium transformations were registered. Prokaryotes (or bacterioplankton) contributed most to ammonium generation rates over the entire water column; these rates increased with depth (0.4-3.1 μM d -1). In surface waters (10 m depth), aerobic ammonium oxidation (potentially by Bacteria and Archaea) was the dominant consumption process (average 0.7 μM d -1) whereas in the subsurface layer (20 and 50 m depth), unexpectedly, eukaryotes accounted for most of its consumption (average 2.1 μM d -1). Nitrification oxidized an important proportion of the ammonium in both layers (from 25% to 100%) and provided regenerated nitrate. The integrated water column rates of chemosynthesis (0.005 g C m -2 d -1) represented a large proportion (51%) of the total dark carbon fixation during the non-upwelling season when integrated rates of photosynthesis are relatively low (0.42 g C m -2 d -1) and microbial food webs dominate the transfer of carbon within this coastal system.

  4. Crystal chemistry and application development of uranyl extended structure and nanoscale materials and actinyl ion-substituted mineral phases

    Science.gov (United States)

    Wylie, Ernest M.

    The worldwide use of nuclear energy presents both significant advantages and challenges for society. Actinide research seeks to address these challenges and drive advancement in the fields of nuclear science and engineering. Here, key aspects of the fuel cycle are examined from both a fundamental and an applications-based perspective. Hydrothermal, ionothermal, room-temperature evaporation, and liquid diffusion synthesis techniques and single-crystal X-ray diffraction were used to study the structures of 18 uranyl compounds and six actinyl-doped mineral phases. These compounds represent a diverse group ranging from unique molecular clusters to novel and known extended structures isolated from aqueous and ionic liquid media. Ultrafiltration techniques were utilized to separate uranyl peroxide nanoclusters from complex aqueous solutions. Inductively coupled plasma optical emission spectroscopy and mass spectrometry were used to quantify elemental distributions in the feed and permeate solutions while Raman spectroscopy, small-angle X-ray scattering, and electrospray ionization mass spectrometry were used to define the characteristics of the cluster species across a range different solution conditions.

  5. Effects of a low-radiotoxicity uranium salt (uranyl acetate) on biochemical and hematological parameters of the catfish, Clarias gariepinus

    Science.gov (United States)

    Al-Ghanim, Khalid A.; Ahmad, Zubair; Al-Kahem Al-Balawi, Hmoud F.; Al-Misned, Fahad; Maboob, Shahid; Suliman, El-Amin M.

    2016-01-01

    Specimens of Clarias gariepinus were treated with lethal (70, 75, 80, 85, 90, and 95 mg/L) and sub-lethal concentrations (8, 12 and 16 mg/L) of uranyl acetate, a low-radiotoxicity uranium salt. The LC 50 value was registered as 81.45 mg/L. The protein and glycogen concentrations in liver and muscles were decreased in the fish exposed to sub-lethal concentrations. The red blood cell (RBC) and white blood cell (WBC) counts, haemoglobin (Hb) concentration and haematocrit (Hct) values were decreased. Different blood indices like mean corpuscular volume (MCV), mean corpuscular haemoglobin (MCH) and mean corpuscular haemoglobin concentration (MCHC) were negatively affected. Level of plasma glucose was elevated whereas protein was decreased. The level of calcium concentration (Ca) was declined in the blood of exposed fish whereas magnesium (Mg) remains unchanged. The activity level of glutamic-oxaloacetic transaminase (GOT) and glutamic-pyruvic transaminase (GPT) was elevated in exposed fish. These effects were more pronounced in the last period of exposure and in higher concentrations. Results of the present study indicate that uranyl acetate has adverse effects on Clarias gariepinus and causes changes in the biochemical and hematological parameters of the fish.

  6. Uranyl ion extraction with conventional PUREX/TRUEX ligands assessed by electroanalytical chemistry at micro liquid/liquid interfaces.

    Science.gov (United States)

    Stockmann, Tom J; Ding, Zhifeng

    2011-10-01

    The facilitated ion transfer (FIT) of uranyl or dioxouranium (UO(2)(2+)) was studied electrochemically using a micro interface between two immiscible electrolytic solutions (micro-ITIES) in order to evaluate the complexation stoichiometry and complexation constants (β) of two widely used ligands in spent fuel reprocessing: tributylphosphate (TBP) and octyl(phenyl)-N,N-diisobutylcarbamoylmethyl-phosphine oxide (CMPO). For the first time, discrete interfacial complexation reaction steps of varying uranyl to the two ligands ratios were resolved using the micro-ITIES hosted at the tip of a 25 μm diameter glass capillary. Two stoichiometries for UO(2)NO(3)TBP(n)(+) were determined including n = 3 and 4 with β values of 3.2 × 10(11) and 3.9 × 10(13), respectively. Subsequently, three distinct complexation reactions of CMPO with UO(2)(2+) were discovered corresponding to UO(2)NO(3)CMPO(2)(+), UO(2)NO(3)CMPO(3)(+), and UO(2)CMPO(5)(2+) whose respective complexation constants were determined to be 8.0 × 10(11), 8.8 × 10(14), and 6.5 × 10(32). The participation of nitrate anions in these complexation reactions is also discussed.

  7. Standard test method for gamma energy emission from fission products in uranium hexafluoride and uranyl nitrate solution

    CERN Document Server

    American Society for Testing and Materials. Philadelphia

    2005-01-01

    1.1 This test method covers the measurement of gamma energy emitted from fission products in uranium hexafluoride (UF6) and uranyl nitrate solution. It is intended to provide a method for demonstrating compliance with UF6 specifications C 787 and C 996 and uranyl nitrate specification C 788. 1.2 The lower limit of detection is 5000 MeV Bq/kg (MeV/kg per second) of uranium and is the square root of the sum of the squares of the individual reporting limits of the nuclides to be measured. The limit of detection was determined on a pure, aged natural uranium (ANU) solution. The value is dependent upon detector efficiency and background. 1.3 The nuclides to be measured are106Ru/ 106Rh, 103Ru,137Cs, 144Ce, 144Pr, 141Ce, 95Zr, 95Nb, and 125Sb. Other gamma energy-emitting fission nuclides present in the spectrum at detectable levels should be identified and quantified as required by the data quality objectives. 1.4 This standard does not purport to address all of the safety concerns, if any, associated with its us...

  8. Characterizing the interaction between uranyl ion and fulvic acid using regional integration analysis (RIA) and fluorescence quenching.

    Science.gov (United States)

    Zhu, Bingqi; Ryan, David K

    2016-03-01

    The development of chemometric methods has substantially improved the quantitative usefulness of the fluorescence excitation-emission matrix (EEM) in the analysis of dissolved organic matter (DOM). In this study, Regional Integration Analysis (RIA) was used to quantitatively interpret EEMs and assess fluorescence quenching behavior in order to study the binding between uranyl ion and fulvic acid. Three fulvic acids including soil fulvic acid (SFA), Oyster River fulvic acid (ORFA) and Suwannee River fulvic acid (SRFA) were used and investigated by the spectroscopic techniques. The EEM spectra obtained were divided into five regions according to fluorescence structural features and two distinct peaks were observed in region III and region V. Fluorescence quenching analysis was conducted for these two regions with the stability constants, ligand concentrations and residual fluorescence values calculated using the Ryan-Weber model. Results indicated a relatively strong binding ability between uranyl ion and fulvic acid samples at low pH (log K value varies from 4.11 to 4.67 at pH 3.50). Fluorophores in region III showed a higher binding ability with fewer binding sites than in region V. Stability constants followed the order, SFA > ORFA > SRFA, while ligand concentrations followed the reverse order, SRFA > ORFA > SFA. A comparison between RIA and Parallel Factor Analysis (PARAFAC) data treatment methods was also performed and good agreement between these two methods (less than 4% difference in log K values) demonstrates the reliability of the RIA method in this study.

  9. Effect of ammonium input over the distribution of iron in the seawater and the phytoplankton in a mesocosm experiment in a North Patagonian fjord

    Directory of Open Access Journals (Sweden)

    N. Sanchez

    2014-09-01

    Full Text Available The distribution and concentration of iron in seawater and plankton were studied under different ammonium concentrations along a 22 day mesocosm experiment in order to assess possible effects of aquaculture over the phytoplankton and the biogeochemistry in fjords of Chile. Brackish and marine water were used in two different setups, each one with 1 control and 4 different NH4+ concentrations. Total Chelex labile (TFeCh, dissolved Chelex labile (DFeCh and DGT labile (FeDGT iron measurements were performed in seawater, wheile the particulate iron content was determined as total (PFe and fractionated (PFeSF for the plankton community. Average concentration per treatment showed higher concentrations for both TFeCh and DFeCh in the marine system compared to the brackish. TFeCh showed general increasing trend in time and with increasing ammonium concentration, exhibiting positive correlation to the chlorophyll and particulate organic carbon content, whereas DFeCh presented an inverse pattern as expected. FeDGT showed an average lower concentration compare to DFeCh with final concentrations significantly lower in treatments with artificial ammonium addition. PFe showed an increasing trend in time and with increasing ammonium in both systems. Yet, when normalized to Chlorophyll a or particulate organic carbon the trend inverted, showing that at higher ammonium loading the iron per Chlorophyll a or particulate organic carbon decreases. PFeSF major changes occurred in the marine system in the ratio between the 20–140 μm and the 2–20 μm fractions, suggesting possible community structure shift. Overall, ammonium input indicated an effect over iron in the seawater and the particulate matter, depending on the iron form and the microbial assemblage. The further changes over the microbial composition due to ammonium addition may affect the cycling of iron, having possible negative or positive feedbacks over major biogeochemical cycles.

  10. Growth of marine bacteria and ammonium regeneration from substrates in different C:N ratios

    Institute of Scientific and Technical Information of China (English)

    WANG Jiangtao; YIN Xiaonan

    2009-01-01

    Natural assemblages of marine bacteria were chosen in a batch culture experiments. The impact of varying nitrogen substrate concentrations and the substrate C:N ratios (C:Ns) on the bacterial C:N ratio (C:NB), the bacterial growth efficiency (BGE) and ammonium regeneration was mainly examined. The C:Ns ratios varied from 5:1 (carbon limitation) to 40:1 (nitrogen limitation) with varying combinations of glucose and NO3. The C:NB ratio had positive relationship with the C:Ns ratio (r=0.93, n=8), whose value was 3.77 when the C:Ns ratio was 5:1 but increased to 6.47 when the C:Ns ratio was 40:1. These results indicate that the C:NB ratio is a potential diagnostic tool for determining the bacterial growth in natural waters controlled by either, carbon or nitrogen. BGE decreased with the declining nitrate concentration and negatively related to C:Ns (r=-0.51,n=8). The average value of BGE was 0.20. This value was a little lower than other reports, which could be induced by the nitrogen source used in our experiments. Finally, regeneration time of ammonium delayed with the increasing C:Ns ratio, which indicates that there were different metabolism mechanisms when bacterial growth was limited by carbon source and nitrogen source.

  11. 76 FR 49449 - Continuation of Antidumping Duty Order on Solid Fertilizer Grade Ammonium Nitrate From the...

    Science.gov (United States)

    2011-08-10

    ... Nitrate From the Russian Federation AGENCY: Import Administration, International Trade Administration... duty investigation on solid fertilizer grade ammonium nitrate (``ammonium nitrate'') from the Russian... and the ITC instituted a second sunset review of the ammonium nitrate suspended investigation....

  12. 76 FR 23569 - Termination of the Suspension Agreement on Solid Fertilizer Grade Ammonium Nitrate From the...

    Science.gov (United States)

    2011-04-27

    ... Nitrate From the Russian Federation and Notice of Antidumping Duty Order AGENCY: Import Administration... (``AD'') Investigation on Solid Fertilizer Grade Ammonium Nitrate from the Russian Federation (``the... determine whether imports of solid fertilizer grade ammonium nitrate (``ammonium nitrate'') from Russia...

  13. Uranyl(VI) nitrate salts: Modeling thermodynamic properties using the binding mean spherical approximation theory and determination of 'fictive' binary data

    Energy Technology Data Exchange (ETDEWEB)

    Ruas, Alexandre; Bernard, Olivier; Caniffi, Barbara; Simonin, Jean-Pierre; Turq, Pierre; Blum, Lesser; Moisy, Philippe [CEA-Valrho Marcoule, DEN/DRCP/SCPS/LCA, Bat 399, BP 17171, 30207 Bagnols-sur-Ceze Cedex (France); Laboratoire LI2C (UMR 7612), Universite P. M. Curie, Boite No. 51, 4 Place Jussieu, 75252 Paris Cedex 05 (France); Department of Physics, POB 23343, University of Puerto Rico, Rio Pedras, Puerto Rico 00931-3343 (United States)

    2006-07-01

    This work is aimed at a description of the thermodynamic properties of highly concentrated aqueous solutions of uranyl nitrate at 25 degrees C. A new resolution of the binding mean spherical approximation (BIMSA) theory, taking into account 1-1 and also 1-2 complex formation, is developed and used to reproduce, from a simple procedure, experimental uranyl nitrate osmotic coefficient variation with concentration. For better consistency of the theory, binary uranyl perchlorate and chloride osmotic coefficients are also calculated. Comparison of calculated and experimental values is made. The possibility of regarding the ternary system UO{sub 2}(NO{sub 3}){sub 2}/HNO{sub 3}/H{sub 2}O as a 'simple' solution (in the sense of Zdanovskii, Stokes, and Robinson) is examined from water activity and density measurements. Also, an analysis of existing uranyl nitrate binary data is proposed and compared with our obtained data. On the basis of the concept of 'simple' solution, values for density and water activity for the binary system UO{sub 2}(NO{sub 3}){sub 2}/H{sub 2}O are proposed in a concentration range on which uranyl nitrate precipitates from measurements on concentrated solutions of the ternary System UO{sub 2}(NO{sub 3}){sub 2}/HNO{sub 3}/H{sub 2}O. This new set of binary data is 'fictive' in the sense that the real binary system is not stable chemically. Finally, a new, interesting predictive capability of the BIMSA theory is shown. (authors)

  14. Effect of temperature on the mechanisms of interaction between uranyl ion and zirconium oxo-phosphate; Effet de la temperature sur les mechanismes d'interaction entre l'ion uranyle et l'oxophosphate de zirconium

    Energy Technology Data Exchange (ETDEWEB)

    Almazan Torres, Maria Guadalupe [Universite de Paris XI Orsay, Orsay (France)

    2007-07-01

    Uranium sorption onto Zr{sub 2}O(PO{sub 4}){sub 2} has been studied between 298 K and 363 K, in 0.1 M NaClO{sub 4} medium. Potentiometric titrations were realized to determine temperature dependency of the acid-base properties (pH{sub pcn}, acidity constants). Classical batch experiments were performed at different temperatures. The sorption experiments revealed that the uranium sorption onto Zr{sub 2}O(PO{sub 4}){sub 2} is favoured with the temperature. Structural characterization of the surface complexes was performed by both Time-Resolved Laser-Induced Fluorescence (TRLIF) and EXAFS spectroscopy. The TRLIF measurements vs. temperature revealed two uranyl surface complexes. No influence of the temperature onto the nature surface complex was observed. The EXAFS analysis showed a splitting of the equatorial oxygen atoms in two shells, corresponding to uranyl bidentate, inner-sphere complexes. The obtained structural uranyl surface complex information was used to simulate (using a constant capacitance model) the sorption edges. The proposed complexes equilibrium model consists of the following surface complexes: ({identical_to}ZrOH){sub 2}UO{sub 2}{sup 2+} and ({identical_to}PO){sub 2}UO{sub 2}. Besides the stability constants for the surface complexes, the thermodynamic parameters {delta}H{sup 0} and {delta}S{sup 0} were determined using the van't Hoff equation. The enthalpy values associated to the U(VI) retention onto Zr{sub 2}O(PO{sub 4}){sub 2}, determined by the temperature dependence of the stability constants, testify that the formation of the complex ({identical_to}PO){sub 2}UO{sub 2} (55 kJ/mol) is endothermic, while no influence of the temperature was observed for the formation of the complex ({identical_to}ZrOH){sub 2}UO{sub 2}{sup 2+}. The adsorption reaction of the last complex is then driven by entropy. In addition, calorimetric measurements of uranium sorption onto Zr{sub 2}O(PO{sub 4}){sub 2} were carried out to directly quantify the enthalpy

  15. Subcellular localization of ammonium transporters in Dictyostelium discoideum

    Directory of Open Access Journals (Sweden)

    Davis Carter T

    2008-12-01

    Full Text Available Abstract Background With the exception of vertebrates, most organisms have plasma membrane associated ammonium transporters which primarily serve to import a source of nitrogen for nutritional purposes. Dictyostelium discoideum has three ammonium transporters, Amts A, B and C. Our present work used fluorescent fusion proteins to determine the cellular localization of the Amts and tested the hypothesis that the transporters mediate removal of ammonia generated endogenously from the elevated protein catabolism common to many protists. Results Using RFP and YFP fusion constructs driven by the actin 15 promoter, we found that the three ammonium transporters were localized on the plasma membrane and on the membranes of subcellular organelles. AmtA and AmtB were localized on the membranes of endolysosomes and phagosomes, with AmtB further localized on the membranes of contractile vacuoles. AmtC also was localized on subcellular organelles when it was stabilized by coexpression with either the AmtA or AmtB fusion transporter. The three ammonium transporters exported ammonia linearly with regard to time during the first 18 hours of the developmental program as revealed by reduced export in the null strains. The fluorescently tagged transporters rescued export when expressed in the null strains, and thus they were functional transporters. Conclusion Unlike ammonium transporters in most organisms, which import NH3/NH4+ as a nitrogen source, those of Dictyostelium export ammonia/ammonium as a waste product from extensive catabolism of exogenously derived and endogenous proteins. Localization on proteolytic organelles and on the neutral contractile vacuole suggests that Dictyostelium ammonium transporters may have unique subcellular functions and play a role in the maintenance of intracellular ammonium distribution. A lack of correlation between the null strain phenotypes and ammonia excretion properties of the ammonium transporters suggests that it is not

  16. [Reasons of high concentration ammonium in Yellow River, China].

    Science.gov (United States)

    Zhang, Xue-qing; Xia, Xing-hui; Yang, Zhi-feng

    2007-07-01

    Ammonium nitrogen contamination is one of the major problems of the Yellow River in China. The speciation, concentration and sources of nitrogen compounds as well as the water environment conditions of the Yellow River had been analyzed to study the reasons for the fact that the ammonium nitrogen concentration was above the water quality standard. In addition, laboratory experiments had been carried out to investigate the effects of suspended sediment (SS) on nitrification rate. The results indicated that the presence of SS could accelerate the nitrification process, therefore, the effects of SS on nitrification rate was not the reason for the high level of ammonium nitrogen in the river. The excessive and continuous input of nitrogen contaminants to the river was the fundamental reason for the high concentration of ammonium nitrogen. Organic and ammonium nitrogen with high concentration inhibitted the nitrification processes. When the initial NH4+ -N concentrations were 10.1, 18.4 and 28.2 mg/L, nitrification efficiencies were 17.4%, 13.0% and 2.5%, respectively. When the initial organic nitrogen concentrations were 5.5 and 8.6 mg/L, the maximum concentrations of ammonium nitrogen produced by the oxidation of organic nitrogen would reach 0.47 and 1.69 mg/L and they would last for 2 days and 6 days, respectively. The oxygen-consuming organics and toxic substance existing in the river water could inhibit the activity of nitrifying bacteria, and thus lead to the accumulation of ammonium nitrogen. In addition, the high pH value of river water resulted in the high concentration of nonionic ammonium nitrogen which would reduce the activity of nitrifying bacteria and decrease the nitrification rates. Besides, low river runoff, low SS content and low activity of nitrifying bacteria resulted in the high level of ammonium nitrogen of the river in the low water season.

  17. Modelling an Ammonium Transporter with SCLS

    Directory of Open Access Journals (Sweden)

    Angelo Troina

    2009-10-01

    Full Text Available The Stochastic Calculus of Looping Sequences (SCLS is a recently proposed modelling language for the representation and simulation of biological systems behaviour. It has been designed with the aim of combining the simplicity of notation of rewrite systems with the advantage of compositionality. It also allows a rather simple and accurate description of biological membranes and their interactions with the environment.In this work we apply SCLS to model a newly discovered ammonium transporter. This transporter is believed to play a fundamental role for plant mineral acquisition, which takes place in the arbuscular mycorrhiza, the most wide-spread plant-fungus symbiosis on earth. Due to its potential application in agriculture this kind of symbiosis is one of the main focuses of the BioBITs project. In our experiments the passage of NH3 / NH4+ from the fungus to the plant has been dissected in known and hypothetical mechanisms; with the model so far we have been able to simulate the behaviour of the system under different conditions. Our simulations confirmed some of the latest experimental results about the LjAMT2;2 transporter. The initial simulation results of the modelling of the symbiosis process are promising and indicate new directions for biological investigations.

  18. Antimicrobial Polymeric Materials with Quaternary Ammonium and Phosphonium Salts

    Directory of Open Access Journals (Sweden)

    Yan Xue

    2015-02-01

    Full Text Available Polymeric materials containing quaternary ammonium and/or phosphonium salts have been extensively studied and applied to a variety of antimicrobial-relevant areas. With various architectures, polymeric quaternary ammonium/phosphonium salts were prepared using different approaches, exhibiting different antimicrobial activities and potential applications. This review focuses on the state of the art of antimicrobial polymers with quaternary ammonium/phosphonium salts. In particular, it discusses the structure and synthesis method, mechanisms of antimicrobial action, and the comparison of antimicrobial performance between these two kinds of polymers.

  19. Time-Resolved Infrared Reflectance Studies of the Dehydration-Induced Transformation of Uranyl Nitrate Hexahydrate to the Trihydrate Form

    Energy Technology Data Exchange (ETDEWEB)

    Johnson, Timothy J.; Sweet, Lucas E.; Meier, David E.; Mausolf, Edward J.; Kim, Eunja; Weck, Philippe F.; Buck, Edgar C.; McNamara, Bruce K.

    2015-10-01

    Uranyl nitrate is a key species in the nuclear fuel cycle. However, this species is known to exist in different states of hydration, including the hexahydrate ([UO2(NO3)2(H2O)6] often called UNH), the trihydrate [UO2(NO3)2(H2O)3 or UNT], and in very dry environments the dihydrate form [UO2(NO3)2(H2O)2]. Their relative stabilities depend on both water vapor pressure and temperature. In the 1950s and 1960s the different phases were studied by infrared transmission spectroscopy, but were limited both by instrumental resolution and by the ability to prepare the samples for transmission. We have revisited this problem using time-resolved reflectance spectroscopy, which requires no sample preparation and allows dynamic analysis while the sample is exposed to a flow of N2 gas. Samples of known hydration state were prepared and confirmed via X-ray diffraction patterns of known species. In reflectance mode the hexahydrate UO2(NO3)2(H2O)6 has a distinct uranyl asymmetric stretch band at 949.0 cm-1 that shifts to shorter wavelengths and broadens as the sample desiccates and recrystallizes to the trihydrate, first as a shoulder growing in on the blue edge but ultimately results in a doublet band with reflectance peaks at 966 and 957 cm-1. The data are consistent with transformation from UNH to UNT as UNT has two inequivalent UO22+ sites. The dehydration of UO2(NO3)2(H2O)6 to UO2(NO3)2(H2O)3 is both a structural and morphological change that has the lustrous lime green UO2(NO3)2(H2O)6 crystals changing to the matte greenish yellow of the trihydrate solid. The phase transformation and crystal structures were confirmed by density functional theory calculations and optical microscopy methods, both of which showed a transformation with two distinct sites for the uranyl cation in the trihydrate, with but one in the hexahydrate.

  20. 14N NQR and relaxation in ammonium nitrate

    Science.gov (United States)

    Stephenson, David

    2015-04-01

    The complete 14N nuclear quadrupole resonance (NQR) spectrum of ammonium nitrate is presented recorded using two double resonance techniques - double contact cross relaxation and zero field NQR. The spectra gave the quadrupole coupling constant (Qcc) and asymmetry parameter ( η) values for the nitro of 611 kHz, 0.229 and that for the ammonium nitrogen of 242 kHz, 0.835. The three relaxation transition probabilities have been determined for both the nitro and ammonium nitrogen atoms. The bi-exponential relaxation times (T 1) were measured at 295 K. The values for nitro are 16.9 s and 10.5 s and that of the ammonium are 23.0 s and 16.4 s.

  1. Synthesis and Antibacterial Activity of Novel Quaternary Ammonium Pyridoxine Derivatives.

    Science.gov (United States)

    Shtyrlin, Nikita V; Sapozhnikov, Sergey V; Koshkin, Sergey A; Iksanova, Alfiya G; Sabirov, Arthur H; Kayumov, Airat R; Nureeva, Aliya A; Zeldi, Marina I; Shtyrlin, Yurii G

    2015-01-01

    A series of 26 quaternary ammonium pyridoxine derivatives were synthesized and their cytotoxicity and antibacterial activities against clinically relevant bacterial strains were tested in vitro. The antibacterial activity of mono-ammonium salts increased with the rise of the lipophilicity and compound 3,3,5-trimethyl-8,8-dioctyl-1,7,8,9-tetrahydro-[1,3]dioxino[5,4-d]pyrrolo[3,4-b]pyridin-8-ium chloride (2d) reaches a maximum among them. Bis-ammonium salt of pyridoxine 4 with two dimethyloctylamine groups also demonstrated high antibacterial activity despite lower lipophilicity. The results of MTT assay indicated that HEK 293 cells were more sensitive than HSF to quaternary ammonium pyridoxine derivatives. Compounds 2d and 4 did not induce the damage of the DNA and might be of interest in the development of new antimicrobials.

  2. Direct esterification of ammonium salts of carboxylic acids

    Science.gov (United States)

    Halpern, Yuval

    2003-06-24

    A non-catalytic process for producing esters, the process comprising reacting an ammonium salt of a carboxylic acid with an alcohol and removing ammonia from the reaction mixture. Selectivities for the desired ester product can exceed 95 percent.

  3. Ammonium removal by modified zeolite from municipal wastewater

    Institute of Scientific and Technical Information of China (English)

    ZHAO Ya-ping; GAO Ting-yao; JIANG Shang-ying; CAO Da-wen

    2004-01-01

    Ammonium removal by modified zeolite, H-form and Na-form zeolite, were examined by batch-type methods. The adsorption of ammonium on modified zeolite was exothermic process. The saturation adsorption capacity of ammonium on H-form and Na-form zeolite were 21.23 and 41.15 mg/g, respectively. After ten times adsorption- desorption-readsorption cycles the standard deviations of H-form and Na-form zeolite were 6.34% and 6.59%. The zeolite adsorption process has proved cost effective and practical in reducing ammonium by H-form and Na-form zeolite in municipal wastewater from concentration 27.68 mg/L to 2.80 mg/L and 5.91 mg/L.

  4. {sup 14}N NQR and relaxation in ammonium nitrate

    Energy Technology Data Exchange (ETDEWEB)

    Stephenson, David, E-mail: david.stephenson@sta.uwi.edu [University of the West Indies, Chemistry Department (Trinidad and Tobago)

    2015-04-15

    The complete {sup 14}N nuclear quadrupole resonance (NQR) spectrum of ammonium nitrate is presented recorded using two double resonance techniques – double contact cross relaxation and zero field NQR. The spectra gave the quadrupole coupling constant (Qcc) and asymmetry parameter (η) values for the nitro of 611 kHz, 0.229 and that for the ammonium nitrogen of 242 kHz, 0.835. The three relaxation transition probabilities have been determined for both the nitro and ammonium nitrogen atoms. The bi-exponential relaxation times (T {sub 1}) were measured at 295 K. The values for nitro are 16.9 s and 10.5 s and that of the ammonium are 23.0 s and 16.4 s.

  5. Fixed Ammonium Content and Maximum Capacity of Ammonium Fixation in Major Types of Tillage Soils in Hunan Province, China

    Institute of Scientific and Technical Information of China (English)

    ZHANG Yang-zhu; HUANG Shun-hong; WAN Da-juan; HUANG Yun-xiang; ZHOU Wei-jun; ZOU Ying-bin

    2007-01-01

    In order to understand the status of fixed ammonium, fixed ammonium content, maximum capacity of ammonium fixation, and their influencing factors in major types of tillage soils of Hunan Province, China, were studied with sampling on fields, and laboratory incubation and determination. The main results are summarized as follows: (1) Content of fixed ammonium in the tested soils varies greatly with soil use pattern and the nature of parent material. For the paddy soils, it ranges from 135.4 ± 57.4 to 412.8±32.4 mg kg-1, with 304.7±96.7 mg kg-1 in average; while it ranges from 59.4 to 435.7 mg kg-1, with 230.1 ± 89.2 mg kg1 in average for the upland soils. The soils developed from limnic material and slate had higher fixed ammonium content than the soils developed from granite. The percentage of fixed ammonium to total N in the upland soils is always higher than that in the paddy soils. It ranges from 6.1 ± 3.6% to 16.6 ±4.6%, with 14.0% ± 5.1% in average for the paddy soils and it amounted to 5.8 ±2.0% to 40.1 ± 17.8%, with 23.5 ± 14.2% in average for upland soils. (2) The maximum capacity of ammonium fixation has the same trend with the fixed ammonium content in the tested soils. For all the tested soils, the percentage of recently fixed ammonium to maximum capacity of ammonium fixation is always bellow 20% and it may be due to the fact that the soils have high fertility and high saturation of ammonium-fixing site. (3) The clay content and clay composition in the tested soils are the two important factors influe ncing their fixed ammonium content and maximum capacity of ammonium fixation. The results showed that hydrous mica is the main 2:1 type clay mineral in <0.02 mm clay of the paddy soils, and its content in 0.02-0.002 mm clay is much higher than that in < 0.002 mm clay of the soils. The statistical analysis showed that both the fixed ammonium content and the maximum capacity of ammonium fixation of the paddy soils were positively correlated with

  6. Ammonium Metabolism Enzymes Aid Helicobacter pylori Acid Resistance

    OpenAIRE

    2014-01-01

    The gastric pathogen Helicobacter pylori possesses a highly active urease to support acid tolerance. Urea hydrolysis occurs inside the cytoplasm, resulting in the production of NH3 that is immediately protonated to form NH4+. This ammonium must be metabolized or effluxed because its presence within the cell is counterproductive to the goal of raising pH while maintaining a viable proton motive force (PMF). Two compatible hypotheses for mitigating intracellular ammonium toxicity include (i) th...

  7. Flotation and adsorption of quaternary ammonium salts collectors on kaolinite of different particle size

    Institute of Scientific and Technical Information of China (English)

    Jiang Hao; Liu Guorong; Hu Yuehua; Xu Longhua; Yu Yawen; Xie Zhen; Chen Haochuan

    2013-01-01

    The flotation behaviors of decyltrimethylammonium (103C),dodecyltrimethylammonium chloride (DTAC),tetradecyltrimethylammonium chloride (TTAC) and cetyltrimethylammonium chloride (CTAC) on kaolinite of different particle size fraction were studied.The adsorbed amount and adsorption isotherms of collectors on kaolinite were determined for painstaking investigation into the adsorption of quaternary amines at kaolinite-water interface by ultraviolet spectrophotometer methods.The flotation results show that the flotation recovery of kaolinite of different particle fraction increases with an increase in pH when 103C,DTAC,TrAC and CTAC are used as collectors.As the concentration of collectors increases,the flotation recovery increases.Particle size of kaolinite has a strong effect on flotation.The flotation recovery of fine kaolinite decreases with the carbon chain of quaternary ammonium salts collectors increasing,while coarse kaolinite is on the contrary.The adsorbed amount tests and adsorption isotherms show that adsorbed amount increases when the particle size of kaolinite increases or when the carbon chain length of quaternary ammonium salts increases.Within the range of flotation collector concentration,the longer the hydrocarbon chain,the more probable to be absolutely adsorbed by fine kaolinite particles and then the lower the collector concentration in the bulk,which leds to lower flotation recovery.

  8. Ethane 1-hydroxy-1, 1-diphosphonate (EHDP) counteracts the inhibitory effect of uranyl nitrate on bone formation

    Energy Technology Data Exchange (ETDEWEB)

    Ubios, A.M.; Guglielmotti, M.B. (Univ. of Buenos Aires (Argentina)); Cabrini, R.L. (Univ. of Buenos Aires (Argentina) National Atomic Energy Commission, Buenos Aires (Argentina))

    The beneficial effect of ethane 1-hydroxy-1, 1-diphosphonate (EHDP) in restoring the inhibition of bone formation in cases of acute uranium intoxication is presented. Bone formation was studied histomorphometrically in a model of alveolar bone healing. After tooth extraction, 40 rats were divided into 4 groups that received (1) no further treatment, (2) 10 daily intraperitoneal injections of 7.5 mg/kg of body weight of EHDP, (3) an intraperitoneal injection of 2.0 mg/kg of body weight of uranyl nitrate, and (4) the same treatment as was provided rats in groups 2 and 3. The results showed that the healing of bone did not occur in exposed animals, whereas healing in EHDP-treated exposed animals did not differ from that of nonexposed controls. This effect might result from a blocking and/or competitive action of EHDP and/or the stimulation that EHDP elicits at the doses and in the administration period studied.

  9. Solid state interaction studies on binary nitrate mixtures of uranyl nitrate hexahydrate and lanthanum nitrate hexahydrate at elevated temperatures

    Science.gov (United States)

    Kalekar, Bhupesh; Raje, Naina; Reddy, A. V. R.

    2017-02-01

    Interaction behavior of uranyl nitrate hexahydrate (UNH) and lanthanum nitrate hexahydrate (LaNH) have been investigated on the mixtures in different molar ratios of the two precursors and monitoring the reactions at elevated temperatures with thermoanalytical and X-ray diffraction measurement techniques. During the decomposition of equimolar mixture of LaNH and UNH, formation of lanthanum uranate (U0.5La0.5)O2, was seen by the temperature of 500 °C along with lanthanum oxide (La2O3) and uranium trioxide (UO3). By the temperature of 700 °C, the formation of uranium sesquioxide (U3O8) was observed along with (U0.5La0.5)O2 as end products in uranium rich mixtures. Lanthanum rich compositions decomposed by the temperature of 700 °C to give (U0.5La0.5)O2 and La2O3 as end products.

  10. Radiation chemistry of cis-syn-cis dicyclohexano-18-crown-6 (DCH18C6): Acidity and uranyl nitrate dependence

    Energy Technology Data Exchange (ETDEWEB)

    Draye, Micheline [Laboratoire de Chimie Moleculaire et Environnement (EA1651), Universite de Savoie-Polytech' Savoie, Campus Scientifique, 73376 Le Bourget du Lac Cedex (France)], E-mail: micheline.draye@univ-savoie.fr; Favre-Reguillon, Alain [Laboratoire de Chimie Organique (UMR7084), Conservatoire National des Arts et Metiers, 2 rue conte, 75003 Paris (France); Faure, Rene [Laboratoire des sciences analytiques, UMR CNRS 5180, Universite Claude Bernard, Lyon 1, 43 boulevard du 11 Novembre 1918, 69622 Villeurbanne Cedex (France); Lemaire, Marc [Laboratoire de Catalyse et Synthese Organique, UMR CNRS 5246, Institut de Chimie et Biochimie Moleculaires et Supramoleculaires, Universite Lyon 1 CPE, 43 boulevard du 11 novembre 1918, Villeurbanne 69622 (France)

    2008-05-15

    The cis-syn-cis isomer of dicyclohexano-18-crown-6 (DCH18C6) has been shown to be an efficient extractant able to perform the separation of Pu(IV) and U(VI) from fission products and then the separation of Pu(IV) from U(VI) without valence exchange as required in the PUREX process. This macrocycle was irradiated in nitric acid with a {sup 137}Cs {gamma} source to study its radiation chemical stability. Radiation chemical yields (G) were determined by gas chromatography. The results show that the presence of uranyl nitrate has a strong influence on DCH18C6 radiation chemical stability. Indeed, the presence of this template ion increases the macrocycle stability by promoting fragments recombination.

  11. Mutagenicity of quaternary ammonium salts containing carbohydrate moieties

    Energy Technology Data Exchange (ETDEWEB)

    Dmochowska, Barbara [Department of Carbohydrate Chemistry, University of Gdansk, Sobieskiego 18, 80-952 Gdansk (Poland); Piosik, Jacek; Woziwodzka, Anna [Intercollegiate Faculty of Biotechnology, University of Gdansk and Medical University of Gdansk, Kladki 24, 80-822 Gdansk (Poland); Sikora, Karol; Wisniewski, Andrzej [Department of Carbohydrate Chemistry, University of Gdansk, Sobieskiego 18, 80-952 Gdansk (Poland); Wegrzyn, Grzegorz, E-mail: wegrzyn@biotech.univ.gda.pl [Department of Molecular Biology, University of Gdansk, Kladki 24, 80-822 Gdansk (Poland)

    2011-10-15

    Highlights: {yields} A series of quaternary ammonium salts containing carbohydrate moieties, with configuration D-galacto, D-gluco and D-manno, was synthesized and characterized. {yields} The quaternary ammonium salts containing carbohydrate moieties revealed potent mutagenic activities, as assessed by using the Vibrio harveyi bioluminescence mutagenicity test. {yields} The N-[2-(D-glycopyranosyloxy)ethyl]-N,N,N-trimethylaminium salts were of the highest activity in the mutagenicity assay. {yields} We suggest that quaternary ammonium salts may be more hazardous than previously supposed. - Abstract: Quaternary ammonium salts are widely used in industrial, agricultural, healthcare and domestic applications. They are believed to be safe compounds, with little or no health hazard to humans. However, in this report, we demonstrate that a series of newly synthesized quaternary ammonium salts containing carbohydrate moieties reveal potent mutagenic activities, as assessed by using the Vibrio harveyi bioluminescence mutagenicity test. D-Gluco- and D-galacto-derivatives were found to have a higher mutagenic potential than D-manno-derivatives. Among the former groups of compounds, the N-[2-(D-glycopyranosyloxy)ethyl]-N,N,N-trimethylaminium salts were of the highest activity in the mutagenicity assay. These results suggest that the safety of quaternary ammonium salts may be lower than previously supposed, indicating a need for testing such compounds for their mutagenicity.

  12. An experimental and ab initio study on the abiotic reduction of uranyl by ferrous iron

    Science.gov (United States)

    Taylor, S. D.; Marcano, M. C.; Rosso, K. M.; Becker, U.

    2015-05-01

    It is important to understand the mechanisms controlling the removal of uranyl from solution from an environmental standpoint, particularly whether soluble Fe(II) is capable of reducing soluble U(VI) to insoluble U(IV). Experiments were performed to shed light into discrepancies of recent studies about precipitation of U-containing solids without changing oxidation states versus precipitation/reduction reactions, especially with respect to the kinetics of these reactions. To understand the atomistic mechanisms, thermodynamics, and kinetics of these redox processes, ab initio electron transfer (ET) calculations, using Marcus theory, were applied to study the reduction of U(VI)aq to U(V)aq by Fe(II)aq (the first rate-limiting ET-step). Outer-sphere (OS) and inner-sphere (IS) Fe-U complexes were modeled to represent simple species within a homogeneous environment through which ET could occur. Experiments on the chemical reduction were performed by reacting 1 mM Fe(II)aq at pH 7.2 with high (i.e., 0.16 mM) and lower (i.e., 0.02 mM) concentrations of U(VI)aq. At higher U concentration, a rapid decrease in U(VI)aq was observed within the first hour of reaction. XRD and XPS analyses of the precipitates confirmed the presence of (meta)schoepite phases, where up to ∼25% of the original U was reduced to U4+ and/or U5+-containing phases. In contrast, at 0.02 mM U, the U(VI)aq concentration remained fairly constant for the first 3 h of reaction and only then began to decrease due to slower precipitation kinetics. XPS spectra confirm the partial chemical reduction U associated with the precipitate (up to ∼30%). Thermodynamic calculations support that the reduction of U(VI)aq to U(IV)aq by Fe(II)aq is energetically unfavorable. The batch experiments in this study show U(VI) is removed from solution by precipitation and that transitioning to a heterogeneous system in turn enables the solid U phase to be partially reduced. Ab initio ET calculations revealed that OS ET is

  13. Design and Construction of Experiment for Direct Electron Irradiation of Uranyl Sulfate Solution: Bubble Formation and Thermal Hydraulics Studies

    Energy Technology Data Exchange (ETDEWEB)

    Chemerisov, Sergey [Argonne National Lab. (ANL), Argonne, IL (United States); Gromov, Roman [Argonne National Lab. (ANL), Argonne, IL (United States); Makarashvili, Vakho [Argonne National Lab. (ANL), Argonne, IL (United States); Heltemes, Thad [Argonne National Lab. (ANL), Argonne, IL (United States); Sun, Zaijing [Argonne National Lab. (ANL), Argonne, IL (United States); Wardle, Kent E. [Argonne National Lab. (ANL), Argonne, IL (United States); Bailey, James [Argonne National Lab. (ANL), Argonne, IL (United States); Quigley, Kevin [Argonne National Lab. (ANL), Argonne, IL (United States); Stepinski, Dominique [Argonne National Lab. (ANL), Argonne, IL (United States); Vandegrift, George [Argonne National Lab. (ANL), Argonne, IL (United States)

    2014-10-01

    Argonne is assisting SHINE Medical Technologies in developing SHINE, a system for producing fission-product 99Mo using a D/T-accelerator to produce fission in a non-critical target solution of aqueous uranyl sulfate. We have developed an experimental setup for studying thermal-hydraulics and bubble formation in the uranyl sulfate solution to simulate conditions expected in the SHINE target solution during irradiation. A direct electron beam from the linac accelerator will be used to irradiate a 20 L solution (sector of the solution vessel). Because the solution will undergo radiolytic decomposition, we will be able to study bubble formation and dynamics and effects of convection and temperature on bubble behavior. These experiments will serve as a verification/ validation tool for the thermal-hydraulic model. Utilization of the direct electron beam for irradiation allows homogeneous heating of a large solution volume and simplifies observation of the bubble dynamics simultaneously with thermal-hydraulic data collection, which will complement data collected during operation of the miniSHINE experiment. Irradiation will be conducted using a 30-40 MeV electron beam from the high-power linac accelerator. The total electron-beam power will be 20 kW, which will yield a power density on the order of 1 kW/L. The solution volume will be cooled on the front and back surfaces and central tube to mimic the geometry of the proposed SHINE solution vessel. Also, multiple thermocouples will be inserted into the solution vessel to map thermal profiles. The experimental design is now complete, and installation and testing are in progress.

  14. Uranyl-glycine-water complexes in solution: comprehensive computational modeling of coordination geometries, stabilization energies, and luminescence properties.

    Science.gov (United States)

    Su, Jing; Zhang, Kai; Schwarz, W H Eugen; Li, Jun

    2011-03-21

    Comprehensive computational modeling of coordination structures, thermodynamic stabilities, and luminescence spectra of uranyl-glycine-water complexes [UO(2)(Gly)(n)aq(m)](2+) (Gly = glycine, aq = H(2)O, n = 0-2, m = 0-5) in aqueous solution has been carried out using relativistic density functional approaches. The solvent is approximated by a dielectric continuum model and additional explicit water molecules. Detailed pictures are obtained by synergic combination of experimental and theoretical data. The optimal equatorial coordination numbers of uranyl are determined to be five. The energies of several complex conformations are competitively close to each other. In non-basic solution the most probable complex forms are those with two water ligands replaced by the bidentate carboxyl groups of zwitterionic glycine. The N,O-chelation in non-basic solution is neither entropically nor enthalpically favored. The symmetric and antisymmetric stretch vibrations of the nearly linear O-U-O unit determine the luminescence features. The shapes of the vibrationally resolved experimental solution spectra are reproduced theoretically with an empirically fitted overall line-width parameter. The calculated luminescence origins correspond to thermally populated, near-degenerate groups of the lowest electronically excited states of (3)Δ(g) and (3)Φ(g) character, originating from (U-O)σ(u) → (U-5f)δ(u),ϕ(u) configurations of the linear [OUO](2+) unit. The intensity distributions of the vibrational progressions are consistent with U-O bond-length changes around 5 1/2 pm. The unusually high intensity of the short wavelength foot is explained by near-degeneracy of vibrationally and electronically excited states, and by intensity enhancement through the asymmetric O-U-O stretch mode. The combination of contemporary computational chemistry and experimental techniques leads to a detailed understanding of structures, thermodynamics, and luminescence of actinide compounds, including

  15. Growth and metabolism of Saccharomyces cerevisiae in chemostat cultures under carbon-, nitrogen-, or carbon- and nitrogen-limiting conditions.

    OpenAIRE

    Larsson, C; von Stockar, U.; Marison, I; Gustafsson, L.

    1993-01-01

    Aerobic chemostat cultures of Saccharomyces cerevisiae were performed under carbon-, nitrogen-, and dual carbon- and nitrogen-limiting conditions. The glucose concentration was kept constant, whereas the ammonium concentration was varied among different experiments and different dilution rates. It was found that both glucose and ammonium were consumed at the maximal possible rate, i.e., the feed rate, over a range of medium C/N ratios and dilution rates. To a small extent, this was due to a c...

  16. Determination of the stability of the uranyl ion sipped in {tau}-hydrogen phosphate of zirconium in sodic form; Determinacion de la estabilidad del ion uranilo sorbido en {tau}-hidrogenofosfato de zirconio en forma sodica

    Energy Technology Data Exchange (ETDEWEB)

    Ordonez R, E.; Fernandez V, S.M. [ININ, 52045 Ocoyoacac, Estado de Mexico (Mexico); Drot, R.; Simoni, E. [Universite de Paris-Sud-XI, Institut de Physique Nucleaire d' Orsay, Groupe de radiochimie, Bat. 100, 91406 Orsay (France)]. e-mail: edo@nuclear.inin.mx

    2005-07-01

    The stability of the uranyl sipped in the zirconium {tau}-hydrogen phosphate in sodic form ({tau}-NaZrP), was carried out characterizing the complexes formed by Laser spectroscopy in the visible region and by X-ray photoelectron spectroscopy. The material was prepared by a new synthesis technique working in nitrogen atmosphere and to low temperatures. The sorption of the uranyl ion was made in acid media with concentrations of 10{sup -4} and 10{sup -5} of uranyl nitrate and with ion forces of 0.1 and 0.5 M of NaClO{sub 4}. The spectra of induced fluorescence with laser (TRLFS) show that the uranyl is fixed in very acid media in three well differentiated species, to pH less acid, the specie of long half life disappears and are only those of short half life. The results of the binding energy obtained by XPS indicate that the binding energy of the uranyl confer it a stable character to the complex formed in the {tau}-NaZP, that makes to this material appropriate to retain to the uranyl in solution to high ion forces and in acid media. (Author)

  17. 40 CFR 418.40 - Applicability; description of the ammonium nitrate subcategory.

    Science.gov (United States)

    2010-07-01

    ... ammonium nitrate subcategory. 418.40 Section 418.40 Protection of Environment ENVIRONMENTAL PROTECTION... Ammonium Nitrate Subcategory § 418.40 Applicability; description of the ammonium nitrate subcategory. The provisions of this subpart are applicable to discharges resulting from the manufacture of ammonium...

  18. 76 FR 39847 - Solid Fertilizer Grade Ammonium Nitrate From the Russian Federation; Final Results of the...

    Science.gov (United States)

    2011-07-07

    ... International Trade Administration Solid Fertilizer Grade Ammonium Nitrate From the Russian Federation; Final... investigation on solid fertilizer grade ammonium nitrate (``ammonium nitrate'') from the Russian Federation...: Solid Fertilizer Grade Ammonium Nitrate From the Russian Federation, 64 FR 45236 (August 19, 1999)....

  19. Ammonium excretion and oxygen respiration of tropical copepods and euphausiids exposed to oxygen minimum zone conditions

    Science.gov (United States)

    Kiko, Rainer; Hauss, Helena; Buchholz, Friedrich; Melzner, Frank

    2016-04-01

    Calanoid copepods and euphausiids are key components of marine zooplankton communities worldwide. Most euphausiids and several copepod species perform diel vertical migrations (DVMs) that contribute to the export of particulate and dissolved matter to midwater depths. In vast areas of the global ocean, and in particular in the eastern tropical Atlantic and Pacific, the daytime distribution depth of many migrating organisms corresponds to the core of the oxygen minimum zone (OMZ). At depth, the animals experience reduced temperature and oxygen partial pressure (pO2) and an increased carbon dioxide partial pressure (pCO2) compared to their near-surface nighttime habitat. Although it is well known that low oxygen levels can inhibit respiratory activity, the respiration response of tropical copepods and euphausiids to relevant pCO2, pO2, and temperature conditions remains poorly parameterized. Further, the regulation of ammonium excretion at OMZ conditions is generally not well understood. It was recently estimated that DVM-mediated ammonium supply could fuel bacterial anaerobic ammonium oxidation - a major loss process for fixed nitrogen in the ocean considerably. These estimates were based on the implicit assumption that hypoxia or anoxia in combination with hypercapnia (elevated pCO2) does not result in a down-regulation of ammonium excretion. We exposed calanoid copepods from the Eastern Tropical North Atlantic (ETNA; Undinula vulgaris and Pleuromamma abdominalis) and euphausiids from the Eastern Tropical South Pacific (ETSP; Euphausia mucronata) and the ETNA (Euphausia gibboides) to different temperatures, carbon dioxide and oxygen levels to study their survival, respiration and excretion rates at these conditions. An increase in temperature by 10 °C led to an approximately 2-fold increase of the respiration and excretion rates of U. vulgaris (Q10, respiration = 1.4; Q10, NH4-excretion = 1.6), P. abdominalis (Q10, respiration = 2.0; Q10, NH4-excretion = 2.4) and

  20. Luminescent properties of [UO{sub 2}(TFA){sub 2}(DMSO){sub 3}], a promising material for sensing and monitoring the uranyl ion

    Energy Technology Data Exchange (ETDEWEB)

    Martin-Ramos, Pablo; Silva, Manuela Ramos; Silva, Pedro S. Pereira da [Centro de Fisica da Universidade de Coimbra (CFisUC), Department of Physics, Universidade de Coimbra (Portugal); Costa, Ana L.; Melo, J. Sergio Seixas de [Centro de Quimica de Coimbra, Department of Chemistry, Universidade de Coimbra (Portugal); Pereira, Laura C.J. [Centro de Ciencias e Tecnologias Nucleares, Instituto Superior Tecnico, Universidade de Lisboa, Bobadela LRS (Portugal); Martin-Gil, Jesus, E-mail: pmr@unizar.es [Advanced Materials Laboratory, Escuela Tecnica Superior de Ingenierias Agrarias, University of Valladolid, Palencia (Spain)

    2016-03-15

    An uranyl complex [UO{sub 2}(TFA){sub 2}(DMSO){sub 3}] (TFA=deprotonated trifluoroacetic acid; DMSO=dimethyl sulfoxide) has been successfully synthesized by reacting UO{sub 2}(CH{sub 3}COO){sub 2} ·H{sub 2} O with one equivalent of (CF{sub 3} CO){sub 2} O and DMSO. The complex has been characterized by single-crystal X-ray diffraction, X-ray powder diffraction, elemental analysis, FTIR spectroscopy, thermal analysis and absorption and emission spectroscopies. The spectroscopic properties of the material make it suitable for its application in the sensing and monitoring of uranyl in the PUREX process. (author)

  1. Novel approach for the ammonium removal by simultaneous heterotrophic nitrification and denitrification using a novel bacterial species co-culture.

    Science.gov (United States)

    Angar, Yassmina; Kebbouche-Gana, Salima; Djelali, Nacer-Eddine; Khemili-Talbi, Souad

    2016-03-01

    Agricultural activities lead excessive emission of ammonia nitrogen in the environment and can profoundly interfere the equilibrium of the natural ecosystems leading to their contamination. Actually, the biological purification of wastewaters is the most adopted technique thanks to its several advantages such as high performance and low energy consumption. For this reason, two novel strains of Alcaligenes sp. S84S3 and Proteus sp. S19 genus were isolated from an activated sludge and applied in the treatment of ammonium and nitrite in aqueous solution. Under the optimum operating conditions of temperature (30 °C), pH (7), carbon substrate (2 g/L of glucose) and duration of incubation time (69 h), the strain Alcaligenes sp. S84S3 could oxidize 65% of the ammonium as high as 272.72 mg-NH4(+)/L. Moreover, during 48 h, the nitrate reduction rate performed by the strain Proteus S19 was about 99 % without production of nitrite intermediate (negligible concentration). Moreover, the coculture of the strains Alcaligenes sp. S84S3 and Proteus sp. S19 could eliminate 65.83% of the ammonium ions without production of toxic forms of nitrogen oxides during a short time of incubation (118 h) at the same operational conditions with providing the aeration in the first treatment phase. The coculture of our isolated strains is assumed to have a good potential for nitrification and denitrification reactions applied in the treatment of wastewater containing ammonium, nitrite and nitrate. As a result, we can consider that the mixed culture is a practical method in the treatment of high-strength ammonium wastewater with reducing of sludge production.

  2. Uranyl complexes formed with a para-t-butylcalix[4]arene bearing phosphinoyl pendant arms on the lower rim. Solid and solution studies

    Energy Technology Data Exchange (ETDEWEB)

    Ramirez, F. de M. [Instituto Nacional de Investigaciones Nucleares, La Marquesa, Ocoyoacac (Mexico). Dept. de Quimica; Varbanov, S. [Bulgarian Academy of Sciences, Sofia (Bulgaria). Inst. of Organic Chemistry with Center of Phytochemistry; Buenzli, J.C.G. [Ecole Polytechnique Federale de Lausanne (EPFL) (Switzerland). Inst. of Chemical Sciences and Engineering; Rivas-Silva, J.F.; Ocana-Bribiesca, M.A. [Instituto de Fisica de la BUAP, Puebla (Mexico); Cortes-Jacome, M.A.; Toledo-Antonio, J.A. [Instituto Mexicano del Petroleo/Programa de Ingenieria Molecular (Mexico)

    2012-07-01

    The current interest in functionalized calixarenes with phosphorylated pendant arms resides in their coordination ability towards f elements and capability towards actinide/rare earth separation. Uranyl cation forms 1:1 and 1:2 (M:L) complexes with a tetra-phosphinoylated p-tert-butylcalix[4]arene, B{sub 4}bL{sup 4}: UO{sub 2}(NO{sub 3}){sub 2}(B{sub 4}bL{sup 4}){sub n} . xH{sub 2}O (n = 1, x = 2, 1; n = 2, x = 6, 2). Spectroscopic data point to the inner coordination sphere of 1 containing one monodentate nitrate anion, one water molecule and the four phosphinoylated arms bound to UO{sub 2}{sup 2+} while in 2, uranyl is only coordinated to calixarene ligands. In both cases the U(VI) ion is 8-coordinate. Uranyl complexes display enhanced metal-centred luminescence due to energy transfer from the calixarene ligands; the luminescence decays are bi-exponential with associated lifetimes in the ranges 220 {mu}s < {tau}{sub s} < 250 {mu}s and 630 {mu}s < {tau}{sub L} < 640 {mu}s, pointing to the presence of two species with differently coordinated calixarene, as substantiated by a XPS study of U(4f{sub 5/2,7/2}), O(1s) and P(2p) levels on solid state samples. The extraction study of UO{sub 2}{sup 2+} cation and trivalent rare-earth (Y, La, Eu) ions from acidic nitrate media by B{sub 4}bL{sup 4} in chloroform shows the uranyl cation being much more extracted than rare earths. (orig.)

  3. Preliminary Assessment of Potential for Metal-Ligand Speciation in Aqueous Solution via the Liquid Sampling-Atmospheric Pressure Glow Discharge (LS-APGD) Ionization Source: Uranyl Acetate.

    Science.gov (United States)

    Zhang, Lynn X; Manard, Benjamin T; Powell, Brian A; Marcus, R Kenneth

    2015-07-21

    The determination of metals, including the generation of metal-ligand speciation information, is essential across a myriad of biochemical, environmental, and industrial systems. Metal speciation is generally affected by the combination of some form of chromatographic separation (reflective of the metal-ligand chemistry) with element-specific detection for the quantification of the metal composing the chromatographic eluent. Thus, the identity of the metal-ligand is assigned by inference. Presented here, the liquid sampling-atmospheric pressure glow discharge (LS-APGD) is assessed as an ionization source for metal speciation, with the uranyl ion-acetate system used as a test system. Molecular mass spectra can be obtained from the same source by simple modification of the sustaining electrolyte solution. Specifically, chemical information pertaining to the degree of acetate complexation of uranyl ion (UO2(2+)) is assessed as a function of pH in the spectral abundance of three metallic species: inorganic (nonligated) uranyl, UO2Ac(H2O)n(MeOH)m(+), and UO2Ac2(H2O)n(MeOH)(m)H(+) (n = 1, 2, 3, ...; m = 1, 2, 3, ...). The product mass spectra are different from what are obtained from electrospray ionization sources that have been applied to this system. The resulting relationships between the speciation and pH values have been compared to calculated concentrations of the corresponding uranyl species: UO2(2+), UO2Ac(+), UO2Ac2. The capacity for the LS-APGD to affect both atomic mass spectra and structurally significant spectra for organometallic complexes is a unique and potentially powerful combination.

  4. Fractionation of bamboo hemicelluloses by graded saturated ammonium sulphate.

    Science.gov (United States)

    Guan, Ying; Zhang, Bing; Qi, Xian-Ming; Peng, Feng; Yao, Chun-Li; Sun, Run-Cang

    2015-09-20

    The hemicelluloses were isolated with 10% KOH at 25°C from dewaxed and delignified bamboo powder. The alkali-soluble hemicelluloses from Sinocalamus affinis were fractionated by ammonium sulphate precipitation method. The bamboo alkali-soluble hemicelluloses yielded seven hemicellulosic fractions obtained at 0, 5, 15, 25, 40, 55, and 70% saturation with ammonium sulphate. It was found that the more branched hemicelluloses were precipitated at higher ammonium sulphate concentrations (55 and 70%), the more linear hemicelluloses were precipitated at lower ammonium sulphate concentrations (0, 5, 15, 25, and 40%). The molecular weights of hemicellulosic fractions become lower from 35,270 (H0) to 18,680 (H70)gmol(-1) with the increasing concentrations of saturated ammonium sulphate from 0 to 70%. Based on the FT-IR, (1)H, (13)C and 2D HSQC NMR studies, the alkali-soluble hemicelluloses were 4-O-methyl-glucuronoarabinoxylans composed of the (1→4)-linked β-d-xylopyranosyl backbone with branches at O-3 of α-L-arabinofuranosyl or at O-2 of 4-O-methyl-α-d-glucuronic acid.

  5. A maritime pine antimicrobial peptide involved in ammonium nutrition.

    Science.gov (United States)

    Canales, Javier; Avila, Concepción; Cánovas, Francisco M

    2011-09-01

    A large family of small cysteine-rich antimicrobial peptides (AMPs) is involved in the innate defence of plants against pathogens. Recently, it has been shown that AMPs may also play important roles in plant growth and development. In previous work, we have identified a gene of the AMP β-barrelin family that was differentially regulated in the roots of maritime pine (Pinus pinaster Ait.) in response to changes in ammonium nutrition. Here, we present the molecular characterization of two AMP genes, PpAMP1 and PpAMP2, showing different molecular structure and physicochemical properties. PpAMP1 and PpAMP2 displayed different expression patterns in maritime pine seedlings and adult trees. Furthermore, our expression analyses indicate that PpAMP1 is the major form of AMP in the tree, and its relative abundance is regulated by ammonium availability. In contrast, PpAMP2 is expressed at much lower levels and it is not regulated by ammonium. To gain new insights into the function of PpAMP1, we over-expressed the recombinant protein in Escherichia coli and demonstrated that PpAMP1 strongly inhibited yeast growth, indicating that it exhibits antimicrobial activity. We have also found that PpAMP1 alters ammonium uptake, suggesting that it is involved in the regulation of ammonium ion flux into pine roots.

  6. Effects of bisphenol A on ammonium assimilation in soybean roots.

    Science.gov (United States)

    Sun, Hai; Wang, Li Hong; Zhou, Qing; Huang, Xiao Hua

    2013-12-01

    Bisphenol A (BPA), which is ubiquitous in the environment, is an example of an endocrine-disrupting compound (EDC). Ammonium assimilation has an important function in plant growth and development. However, insufficient information on the potential effect of BPA on ammonium assimilation in plants is available. In this study, the effects of BPA on ammonium assimilation in roots of soybean seedlings were investigated. During the stress period, 1.5 mg L(-1) of BPA improved glutamine synthetase (GS)/glutamate synthase (GOGAT) cycle and glutamate dehydrogenase (GDH) pathway in ammonium assimilation. The amino acid and the soluble protein contents increased in the soybeans. At 17.2 and 50.0 mg L(-1) of BPA, the GS/GOGAT cycle was inhibited and the GDH pathway was promoted. The amino acid content increased and the soluble protein content decreased. During the recovery period, the GS/GOGAT cycle and the GDH pathway recovered at 1.5 and 17.2 mg L(-1) of BPA but not at 50.0 mg L(-1) of BPA. The amino acid content continuously increased and the soluble protein content decreased compared with those in the control treatment. In summary, BPA treatment could affect the contents of soluble protein and amino acid in the soybean roots by regulating ammonium assimilation.

  7. Removing ammonium from water using modified corncob-biochar.

    Science.gov (United States)

    Vu, Thi Mai; Trinh, Van Tuyen; Doan, Dinh Phuong; Van, Huu Tap; Nguyen, Tien Vinh; Vigneswaran, Saravanamuthu; Ngo, Huu Hao

    2017-02-01

    Ammonium pollution in groundwater and surface water is of major concern in many parts of the world due to the danger it poses to the environment and people's health. This study focuses on the development of a low cost adsorbent, specifically a modified biochar prepared from corncob. Evaluated here is the efficiency of this new material for removing ammonium from synthetic water (ammonium concentration from 10 to 100mg/L). The characteristics of the modified biochar were determined by Brunauer-Emmett-Teller (BET) test, Fourier transform infrared spectroscopy (FTIR) and Scanning electron microscopy (SEM). It was found that ammonium adsorption on modified biochar strongly depended on pH. Adsorption kinetics of NH4(+)-N using modified biochar followed the pseudo-second order kinetic model. Both Langmuir and Sips adsorption isotherm models could simulate well the adsorption behavior of ammonium on modificated biochar. The highest adsorption capacity of 22.6mg NH4(+)-N/g modified biochar was obtained when the biochar was modified by soaking it in HNO3 6M and NaOH 0.3M for 8h and 24h, respectively. The high adsorption capacity of the modified biochar suggested that it is a promising adsorbent for NH4(+)-N remediation from water.

  8. Difficultly Extractable Fixed Ammonium in Some Soils of China

    Institute of Scientific and Technical Information of China (English)

    CHENBIYUN; CHENGLILI; 等

    1999-01-01

    Ninety-three soil samples and 19 sedimentary rock samples collected from 21 provinces of China were analyzed for their contents of fixed ammonium and total N by Kjeldahl-HF method.Results showed that amount of difficultly extractable fixed ammonium(the fixed ammonium that is not determinable by Kjeldahl procedures commonly used for soils) in soils ranged from 0 to 202 mg kg-1,It was generally more than 50 mg kg-1 in soils in Changji and Turpan districts,Xinjiang,accounting for 3.2%-36.8% with an average of 13.9% of the total N.For some Orthents derived from purple shale and purple sandstone in Sichuan and Hunan provinces and Chao soils derived from secondary loess in Henan Province and Ningxia Autonomous Region it was generally around 30 mg kg-1,accounting for 4%-7% of the total soil N,and for most of the rest of soils studied,with the exception of some subsoils,no or trace difficultly extractable fixed ammonium could be detected.It was sugested that the difficultly extractable fixed ammonium was originated from parent rock,and for slightly weathered soils derived from parent materials rich in this form of N the Kjeldahl method might give underestimation of total soil N.

  9. Quaternary ammonium salt derivatives of allylphenols with peripheral analgesic effect

    Directory of Open Access Journals (Sweden)

    A. B de Oliveira

    1991-01-01

    Full Text Available Ammonium salt derivatives of natural allylphenols were synthesized with the purpose of obtaining potential peripheral analgesics. These drugs, by virtue of their physicochemical properties, would not be able to cross the blood brain barrier. Their inability to enter into the central nervous system (CNS should prevent several adverse effects observed with classical opiate analgesics (Ferreira et al., 1984. Eugenol (1 O-methyleugenol (5 and safrole (9 were submitted to nitration, reduction and permethylation, leading to the ammonium salts 4, 8 and 12. Another strategy applied to eugenol (1, consisting in its conversion to a glycidic ether (13, opening the epoxide ring with secondary amines and methylation, led to the ammonium salts 16 and 17. All these ammonium salts showed significant peripheral analgesic action, in modified version of the Randall-Sellito test (Ferreira et al. 1978, at non-lethal doses. The ammonium salt 8 showed an activity comparable to that of methylnalorphinium, the prototype of an ideal peripheral analgesic (Ferreira et al., 1984.

  10. Uranyl ion interaction at the water/NiO(100) interface: A predictive investigation by first-principles molecular dynamic simulations

    Energy Technology Data Exchange (ETDEWEB)

    Sebbari, Karim [EDF-R and D, Departement Materiaux et Mecanique des Composants, Les Renardieres, Ecuelles, 77818 Moret Sur Loing (France); Institut de Physique Nucleaire d' Orsay, Universite Paris-Sud, CNRS UMR 8608, 15 rue Georges Clemenceau, Batiment 100, 91406 Orsay Cedex (France); Roques, Jerome; Simoni, Eric [Institut de Physique Nucleaire d' Orsay, Universite Paris-Sud, CNRS UMR 8608, 15 rue Georges Clemenceau, Batiment 100, 91406 Orsay Cedex (France); Domain, Christophe [EDF-R and D, Departement Materiaux et Mecanique des Composants, Les Renardieres, Ecuelles, 77818 Moret Sur Loing (France)

    2012-10-28

    The behavior of the UO{sub 2}{sup 2+} uranyl ion at the water/NiO(100) interface was investigated for the first time using Born-Oppenheimer molecular dynamic simulations with the spin polarized DFT +U extension. A water/NiO(100) interface model was first optimized on a defect-free five layers slab thickness, proposed as a reliable surface model, with an explicit treatment of the solvent. Water molecules are adsorbed with a well-defined structure in a thickness of about 4 A above the surface. The first layer, adsorbed on nickel atoms, remains mainly in molecular form but can partly dissociate at 293 K. Considering low acidic conditions, a bidentate uranyl ion complex was characterized on two surface oxygen species (arising from water molecules adsorption on nickel atoms) with d{sub U-O{sub a{sub d{sub s{sub o{sub r{sub p{sub t{sub i{sub o{sub n}}}}}}}}}}}=2.39 A. This complex is stable at 293 K due to iono-covalent bonds with an estimated charge transfer of 0.58 electron from the surface to the uranyl ion.

  11. Effect of double quaternary ammonium groups on micelle formation of partially fluorinated surfactant.

    Science.gov (United States)

    Matsuoka, Keisuke; Chiba, Nagisa; Yoshimura, Tomokazu; Takeuchi, Emi

    2011-04-15

    To investigate the effect of divalency on the micelle properties, we synthesized divalent cationic surfactants composed of fluorocarbons and double quaternary ammonium groups N,N-dimethyl-N-[2-(N'-trimethylammonium)ethyl]-1-(3-perfluoroalkyl-2-hydroxypropyl) ammonium bromide [C(n)(F)C(3)-2Am; where n (=8 or 10) represents the number of carbon atoms in the fluorocarbon chain]. The double quaternary ammonium groups are continuously combined by the ethylene spacer in the surfactant head group, which clearly distinguishes the molecular design of the surfactant from those of the other typical divalent surfactants, bolaform and gemini types. The presence of the divalent head group results in an advantageous increase in their solubility [i.e., rise in the critical micelle concentration (cmc)]; however, the extra electrostatic repulsion between divalent cations decreases the surface activity in comparison with monovalent homologous fluorinated surfactants. The cmc, surface tension at cmc, and area occupied by a surfactant molecule in aqueous solution at 298.2K are 4.32 mM, 30.6 mN m(-1), and 0.648 nm(2 )molecule(-1), respectively, for C(8)(F)C(3)-2Am, and 1.51 mM, 30.4 mN m(-1), and 0.817 nm(2) molecule(-1), respectively, for C(10)(F)C(3)-2Am. The micellar size and shape were investigated by dynamic light scattering and freeze-fracture transmission electron microscopy (TEM). The TEM micrographs show that C(n)(F)C(3)-2Am (n=8 and 10) mainly forms ellipsoidal micelles approximately 10-100 nm in size for n=8 and approximately 10-20 nm in size for n=10. The degree of counterion binding to micelle was determined by selective electrode potential measurements, and the results of 0.7-0.8 agree with the average values for conventional monovalent ionic surfactants.

  12. The biological activity of quaternary ammonium salts (QASs

    Directory of Open Access Journals (Sweden)

    Ewa Obłąk

    2010-04-01

    Full Text Available Quaternary ammonium salts (QASs, especially those of cationic surfactant character, are applied as antibacterial and antifungal disinfectants. QASs affect lipid-enveloped viruses, including human immunodeficiency virus (HIV and hepatitis B virus (HBV, but not non-enveloped viruses. These compounds are extensively used in domestic (as ingredients of shampoos, hair conditioners, agricultural (as fungicides, pesticides, insecticides, healthcare (as medications, and industrial applications (as biocides, fabric softeners, corrosion inhibitors. The extensive use of quaternary ammonium disinfectants in recent years has led to the development of resistance in microorganisms to these drugs. Thus [i]Staphylococcus[/i] [i]aureus[/i] strains contain the plasmid-carrying genes [i]qacA[/i] and [i]qacB [/i]encoding resistance to quaternary ammonium compounds and acriflavine. The membrane proteins QacA and QacB confer multidrug resistance by exporting the compound by the proton motive force which is generated by the transmembrane electrochemical proton gradient.

  13. [The biological activity of quaternary ammonium salts (QASs)].

    Science.gov (United States)

    Obłak, Ewa; Gamian, Andrzej

    2010-04-19

    Quaternary ammonium salts (QASs), especially those of cationic surfactant character, are applied as antibacterial and antifungal disinfectants. QASs affect lipid-enveloped viruses, including human immunodeficiency virus (HIV) and hepatitis B virus (HBV), but not non-enveloped viruses. These compounds are extensively used in domestic (as ingredients of shampoos, hair conditioners), agricultural (as fungicides, pesticides, insecticides), healthcare (as medications), and industrial applications (as biocides, fabric softeners, corrosion inhibitors). The extensive use of quaternary ammonium disinfectants in recent years has led to the development of resistance in microorganisms to these drugs. Thus Staphylococcus aureus strains contain the plasmid-carrying genes qacA and qacB encoding resistance to quaternary ammonium compounds and acriflavine. The membrane proteins QacA and QacB confer multidrug resistance by exporting the compound by the proton motive force which is generated by the transmembrane electrochemical proton gradient.

  14. Rocket Solid Propellant Alternative Based on Ammonium Dinitramide

    Directory of Open Access Journals (Sweden)

    Grigore CICAN

    2017-03-01

    Full Text Available Due to the continuous run for a green environment the current article proposes a new type of solid propellant based on the fairly new synthesized oxidizer, ammonium dinitramide (ADN. Apart of having a higher specific impulse than the worldwide renowned oxidizer, ammonium perchlorate, ADN has the advantage, of leaving behind only nitrogen, oxygen and water after decomposing at high temperatures and therefore totally avoiding the formation of hydrogen chloride fumes. Based on the oxidizer to fuel ratios of the current formulations of the major rocket solid booster (e.g. Space Shuttle’s SRB, Ariane 5’s SRB which comprises mass variations of ammonium perchlorate oxidizer (70-75%, atomized aluminum powder (10-18% and polybutadiene binder (12-20% a new solid propellant was formulated. As previously stated, the new propellant formula and its variations use ADN as oxidizer and erythritol tetranitrate as fuel, keeping the same polybutadiene as binder.

  15. Study on mechanism of isomerization between ammonium thiocyanate and thiourea

    Science.gov (United States)

    Zhang, Chao-Zhi; Niu, Meng-Xiao

    2016-12-01

    Application of ammonium thiocyanate that can be separated from wastewater in coking plant is limited. It may isomerize to thiourea which has widely applied in industry. However, the isomerization yield is low. Moreover, the isomerization temperature is more than 145 °C. In this paper, the isomerization was investigated. The mechanism of the isomerization was supposed based on quantum chemistry calculations. Ammonia was employed as a catalyst to lower isomerization temperature and improved the yield of thiourea in the isomerization reaction. Results of quantum chemical calculation and experiments support the supposed mechanism. The mechanism can be applied in production of thiourea from isomerization of ammonium thiocyanate. The paper suggests a useful way of resourcizing ammonium thiocyanate in wastewater.

  16. Enrichment culture of marine anaerobic ammonium oxidation (anammox) bacteria

    Institute of Scientific and Technical Information of China (English)

    GUAN Yong-jie

    2016-01-01

    The present study investigates the enrichment of anaerobic ammonium oxidation (anammox) bacteria in the marine environment using sediment samples obtained from the East China Sea and discusses the nitrogen removal efficiency of marine anammox bioreactor. Enrichment of anammox bacteria with simultaneous removal of nitrite and ammonium ions was observed in the Anaerobic Sequencing Batch Reactor under a total nitrogen loading rate of 0.37kg-N m-3day-1. In this study, The nitrogen removal efficiency was up to 80% and the molar-reaction ratio of ammonium, nitrite and nitrate was 1.0:1.22:0.22 which was a little different from a previously reported ratio of 1.0:1.32:0.26 in a freshwater system.

  17. Performance of sulfate-dependent anaerobic ammonium oxidation

    Institute of Scientific and Technical Information of China (English)

    2009-01-01

    The performance of sulfate-dependent anaerobic ammonium oxidation was studied.The results showed that both SO42-and NH4+ were chemically stable under anaerobic conditions.They did not react with each other in the absence of biological catalyst(sludge).The anaerobic digested sludge cultivated in an anaerobic reactor for three years took on the ability of oxidizing ammonium with sulfate anaero-bically.The average reduction of sulfate and ammonium was 71.67 mg.L-1 and 56.82 mg.L-1 at high concentrations.The reaction between SO42-and NH4+ was difficult,though feasible,due to its low standard Gibbs free energy change.The experiment demonstrated that high substrate concentrations and low oxidation-reduction potential(ORP) may be favourable for the biological reaction.

  18. Performance of sulfate-dependent anaerobic ammo-nium oxidation

    Institute of Scientific and Technical Information of China (English)

    ZHANG Lei; ZHENG Ping; HE YuHui; JIN RenCun

    2009-01-01

    The performance of sulfate-dependent anaerobic ammonium oxidation was studied. The results showed that both SO42- and NH4+ were chemically stable under anaerobic conditions. They did not react with each other in the absence of biological catalyst (sludge). The anaerobic digested sludge cultivated in an anaerobic reactor for three years took on the ability of oxidizing ammonium with sulfate anaero-bically. The average reduction of sulfate and ammonium was 71.67 mg.L-1 and 56.82 mg.L-1 at high concentrations.The reaction between SO42- and NH4+ was difficult, though feasible, due to its low standard Gibbs free energy change. The experiment demonstrated that high substrate concentrations and low oxidation-reduction potential (ORP) may be favourable for the biological reaction.

  19. Ammonium and nitrate tolerance in lichens.

    Science.gov (United States)

    Hauck, Markus

    2010-05-01

    Since lichens lack roots and take up water, solutes and gases over the entire thallus surface, these organisms respond more sensitively to changes in atmospheric purity than vascular plants. After centuries where effects of sulphur dioxide and acidity were in the focus of research on atmospheric chemistry and lichens, recently the globally increased levels of ammonia and nitrate increasingly affect lichen vegetation and gave rise to intense research on the tolerance of lichens to nitrogen pollution. The present paper discusses the main findings on the uptake of ammonia and nitrate in the lichen symbiosis and to the tolerance of lichens to eutrophication. Ammonia and nitrate are both efficiently taken up under ambient conditions. The tolerance to high nitrogen levels depends, among others, on the capability of the photobiont to provide sufficient amounts of carbon skeletons for ammonia assimilation. Lowly productive lichens are apparently predisposed to be sensitive to excess nitrogen.

  20. Steady state growth of E. Coli in low ammonium environment

    Science.gov (United States)

    Kim, Minsu; Deris, Barret; Zhang, Zhongge; Hwa, Terry

    2011-03-01

    Ammonium is the preferred nitrogen source for many microorganisms. In medium with low ammonium concentrations, enteric bacteria turn on the nitrogen responsive (ntr) genes to assimilate ammonium. Two proteins in E. coli, Glutamine synthetase (GS) and the Ammonium/methylammonium transporter AmtB play crucial roles in this regard. GS is the major ammonium assimilation enzyme below 1mM of NH4 + . AmtB is an inner membrane protein that transports NH4 + across the cell membrane against a concentration gradient. In order to study ammonium uptake at low NH4 + concentration at neutral pH, we developed a microfluidic flow chamber that maintains a homogenous nutrient environment during the course of exponential cell growth, even at very low concentration of nutrients. Cell growth can be accurately monitored using time-lapse microscopy. We followed steady state growth down to micro-molar range of NH4 + for the wild type and Δ amtB strains. The wild type strain is able to maintain the growth rate from 10mM down to a few uM of NH4 + , while the mutant exhibited reduced growth below ~ 20 ~uM of NH4 + . Simultaneous characterization of the expression levels of GS and AmtB using fluorescence reporters reveals that AmtB is turned on already at 1mM, but contributes to function only below ~ 30 ~uM in the wild-type. Down to ~ 20 ~uM of NH4 + , E.~coli can compensate the loss of AmtB by GS alone.

  1. Precipitation of phenyl and phenoxypenicillin from solutions using ammonium sulfate.

    Science.gov (United States)

    Luengo, J M

    1985-09-01

    An easy, rapid, and available method for separating 6-aminopenicillanic acid (6-APA), benzylpenicillin (penicillin G), and other related molecules from aqueous solutions or complex industrial broths is described. A high concentration of ammonium sulphate induces partially or totally the precipitation of the penicillin present in the solutions, while 6-APA, phenylacetic, and phenoxyacetic acid always remain in the supernatant. The filtration through No. 4 Pyrex glass-fiber filter or Whatman 3MM paper permits the separation of the compounds present in the supernatant from the other ones precipitated. The precipitated product was identified, in all cases, as ammonium penicillin. This method is described here for the first time.

  2. Determination of Ammonium Ion in Lake Water by Voltammetry

    Institute of Scientific and Technical Information of China (English)

    Wu Yun-hua; Fei Jun-jie; Dang Xue-ping; Hu Sheng-shui

    2004-01-01

    An electroanalytical method for the determination of armonium ion using a platinized platinum electrode is described. Under optimized analytical conditions, the linear range of the calibration graphs for ammonium ion is 3. 0×10(-5)-5.0×10-3 mol·L-1.The Method has been applide to the determination of ammonium ion in lake water samples and recoveries of 100%-103%0 are obtained. The results obtained are found to be in good agreement with spectrophotometric results.

  3. Aerosol isotopic ammonium signatures over the remote Atlantic Ocean

    Science.gov (United States)

    Lin, C. T.; Jickells, T. D.; Baker, A. R.; Marca, A.; Johnson, M. T.

    2016-05-01

    We report aerosol ammonium 15N signatures for samples collected from research cruises on the South Atlantic and Caribbean using a new high sensitivity method. We confirm a pattern of isotopic signals from generally light (δ15N -5 to -10‰), for aerosols with very low (ocean, to generally heavier values (δ15N +5 to +10‰), for aerosols collected in temperate and tropical latitudes and with higher ammonium concentrations (>2 nmol m-3). We discuss whether this reflects a mixing of aerosols from two end-members (polluted continental and remote marine emissions), or isotopic fractionation during aerosol transport.

  4. Mutagenic activity of quaternary ammonium salt derivatives of carbohydrates

    Science.gov (United States)

    Sikora, Karol; Woziwodzka, Anna; Piosik, Jacek; Podgórska, Beata

    2016-01-01

    Summary This paper presents a study on a series of quaternary ammonium salt (QAS) derivatives of glucopyranosides with an elongated hydrophobic hydrocarbon chain. The new N-[6-(β-D-glucopyranosyloxy)hexyl]ammonium bromides and their O-acetyl derivatives were analyzed via 1H and 13C NMR spectroscopy. The mutagenic activity of the newly synthesized QAS was investigated using two different techniques: The Vibrio harveyi luminescence assay and the Ames test. The obtained results support previous findings contesting QAS safety and indicate that QAS, specifically pyridinium derivatives, might be mutagenic. PMID:27559394

  5. A Nuclear Reactor and Chemical Processing Design for Production of Molybdenum-99 with Crystalline Uranyl Nitrate Hexahydrate Fuel

    Science.gov (United States)

    Stange, Gary Michael

    Medical radioisotopes are used in tens of millions of procedures every year to detect and image a wide variety of maladies and conditions in the human body. The most widely-used diagnostic radioisotope is technetium-99m, a metastable isomer of technetium-99 that is generated by the radioactive decay of molybdenum-99. For a number of reasons, the supply of molybdenum-99 has become unreliable and the techniques used to produce it have become unattractive. This has spurred the investigation of new technologies that avoid the use of highly enriched uranium to produce molybdenum-99 in the United States, where approximately half of the demand originates. The first goal of this research is to develop a critical nuclear reactor design powered by solid, discrete pins of low enriched uranium. Analyses of single-pin heat transfer and whole-core neutronics are performed to determine the required specifications. Molybdenum-99 is produced directly in the fuel of this reactor and then extracted through a series of chemical processing steps. After this extraction, the fuel is left in an aqueous state. The second goal of this research is to describe a process by which the uranium may be recovered from this spent fuel solution and reconstituted into the original fuel form. Fuel recovery is achieved through a crystallization step that generates solid uranyl nitrate hexahydrate while leaving the majority of fission products and transuranic isotopes in solution. This report provides background information on molybdenum-99 production and crystallization chemistry. The previously unknown thermal conductivity of the fuel material is measured. Following this is a description of the modeling and calculations used to develop a reactor concept. The operational characteristics of the reactor core model are analyzed and reported. Uranyl nitrate crystallization experiments have also been conducted, and the results of this work are presented here. Finally, a process flow scheme for uranium

  6. Ammonium removal by Agrobacterium sp. LAD9 capable of heterotrophic nitrification-aerobic denitrification.

    Science.gov (United States)

    Chen, Qian; Ni, Jinren

    2012-05-01

    Characteristics of ammonium removal by a newly isolated heterotrophic nitrification-aerobic denitrification bacterium Agrobacterium sp. LAD9 were systematically investigated. Succinate and acetate were found to be the most favorable carbon sources for LAD9. Response surface methodology (RSM) analysis demonstrated that maximum removal of ammonium occurred under the conditions with an initial pH of 8.46, C/N ratio of 8.28, temperature of 27.9°C and shaking speed of 150rpm, where temperature and shaking speed produced the largest effect. Further nitrogen balance analysis revealed that 50.1% of nitrogen was removed as gas products and 40.8% was converted to the biomass. Moreover, the occurrence of aerobic denitrification was evidenced by the utilization of nitrite and nitrate as nitrogen sources, and the successful amplifications of membrane bound nitrate reductase and cytochrome cd(1) nitrite reductase genes from strain LAD9. Thus, the nitrogen removal in strain LAD9 was speculated to comply with the mechanism of heterotrophic nitrification coupled with aerobic denitrification (NH(4)(+)-NH(2)OH-NO(2)(-)-N(2)O-N(2)), in which also accompanied with the mutual transformation of nitrite and nitrate. The findings can help in applying appropriate controls over operational parameters in systems involving the use of this kind of strain.

  7. Association with an ammonium-excreting bacterium allows diazotrophic culture of oil-rich eukaryotic microalgae.

    Science.gov (United States)

    Ortiz-Marquez, Juan Cesar Federico; Do Nascimento, Mauro; Dublan, Maria de Los Angeles; Curatti, Leonardo

    2012-04-01

    Concerns regarding the depletion of the world's reserves of oil and global climate change have promoted an intensification of research and development toward the production of biofuels and other alternative sources of energy during the last years. There is currently much interest in developing the technology for third-generation biofuels from microalgal biomass mainly because of its potential for high yields and reduced land use changes in comparison with biofuels derived from plant feedstocks. Regardless of the nature of the feedstock, the use of fertilizers, especially nitrogen, entails a potential economic and environmental drawback for the sustainability of biofuel production. In this work, we have studied the possibility of nitrogen biofertilization by diazotrophic bacteria applied to cultured microalgae as a promising feedstock for next-generation biofuels. We have obtained an Azotobacter vinelandii mutant strain that accumulates several times more ammonium in culture medium than wild-type cells. The ammonium excreted by the mutant cells is bioavailable to promote the growth of nondiazotrophic microalgae. Moreover, this synthetic symbiosis was able to produce an oil-rich microalgal biomass using both carbon and nitrogen from the air. This work provides a proof of concept that artificial symbiosis may be considered an alternative strategy for the low-N-intensive cultivation of microalgae for the sustainable production of next-generation biofuels and other bioproducts.

  8. Ammonium deficiency caused by heterogeneous reactions during a super Asian dust episode

    Science.gov (United States)

    Hsu, Shih-Chieh; Lee, Celine Siu Lan; Huh, Chih-An; Shaheen, Robina; Lin, Fei-Jan; Liu, Shaw Chen; Liang, Mao-Chang; Tao, Jun

    2014-06-01

    Mineral dust particles exert profound impacts on air quality, visibility, and ocean biogeochemistry. Interactions between dust particles and other anthropogenic pollutants modify not only the size spectrum and morphology but also physicochemical properties of dust particles, thereby affecting their radiative properties and ability to act as cloud condensation nuclei and in turn their impact on climate. Here we report field observations on the surface chemical transformations in a super Asian dust plume captured in coastal areas of China and the adjacent marginal seas. The dust plume showed enhanced concentrations of sulfate, nitrate, and calcium along with a decrease in ammonium. The percentages of total Ca in water-soluble form increased from an intrinsic value of ~5% to 25-40% at four stations along the path of the dust plume. From these increases, we estimated the extent to which carbonate was modified by heterogeneous reactions and calculated that the enhanced sulfate and nitrate could account for 40-60% of the observed concentrations. Our observation suggests that the formation of ammonium sulfate via the H2SO4-NH3-H2O ternary system was impeded by heterogeneous reactions in the marine boundary layer when dust loads exceeded a certain threshold. A conceptual model is proposed to elucidate the heterogeneous reactions during the super Asian dust event and their impacts on atmospheric chemistry.

  9. Temperature effects on the interaction mechanisms between the europium (III) and uranyl ions and zirconium diphosphate; Effets de la temperature sur les mecanismes d'interaction entre les ions europium (3) et uranyle et le diphosphate de zirconium

    Energy Technology Data Exchange (ETDEWEB)

    Finck, N

    2006-10-15

    Temperature should remain higher than 25 C in the near field environment of a nuclear waste repository for thousands years. In this context, the aim of this work is to study the temperature influence on the interaction mechanisms between europium (III) and uranyl ions and zirconium diphosphate, as well as the influence of a complexing medium (nitrate) on the sorption of the lanthanide. The experimental definition of the equilibria was achieved by combining a structural investigation with the macroscopic sorption data. Surface complexes were characterized at all temperatures (25 C to 90 C) by TRLFS experiments carried out on dry and in situ samples using an oven. This characterization was completed by XPS experiments carried out at 25 C on samples prepared at 25 C and 90 C. The reaction constants (surface hydration and cations sorption) were obtained by simulating the experimental data with the constant capacitance surface complexation model. The reaction constants temperature dependency allowed one to characterize thermodynamically the different reactions by application of the van't Hoff relation. The validity of this law was tested by performing microcalorimetric measurements of the sorption heat for both cations. (author)

  10. ANALYSIS ON INFLUENCE REGULARITY OF THE AMMONIA-AMMONIUM LEACHING SYSTEM ON LEACHING RATE OF COPPER%不同氨-铵浸出体系对氧化铜矿铜浸出率影响规律的研究

    Institute of Scientific and Technical Information of China (English)

    毛莹博; 方建军; 文娅; 赵文娟; 王珊; 魏志聪

    2012-01-01

    In this paper, through a series of experiment studies about the different ammonia-ammonium coupling of leaching system for the effect of copper oxide ore leaching, a significant influence sequence of the different ammonia-ammonium coupling of leaching system on the leaching rate of copper is determined as following : ammonia-ammonium carbamate > ammonia-ammonium carbonate > ammonia-ammonium chloride > ammonia-ammonium fluoride > ammonia-ammonium bicarbonate > ammonia-ammonium sulfate. The ammonia-ammonium carbamate leaching system is adopted as the experiment study of high calcium and magnesium, low grade and argillaceous copper oxide ore in Xinjiang Water, and the copper leaching rate is as high as 85. 25% .%通过不同氨-铵浸出体系对氧化铜矿浸出影响的试验研究,确定了不同氨-铵浸出体系对铜浸出率的显著性影响顺序是:氨-氨基甲酸铵>氨-碳酸铵>氨-氯化铵>氨-氟化铵>氨-碳酸氢铵>氨-硫酸铵.采用氨-氨基甲酸铵浸出体系对新疆滴水高钙镁低品位泥质氧化铜矿进行浸出试验,铜浸出率高达85.25%.

  11. Aqueous Media Oxidation of Alcohols with Ammonium Persulfate

    Institute of Scientific and Technical Information of China (English)

    IMANZADEH, Gholam Hassan; ZAMANLOO, Mohammad R.; MANSOORI, Yaghoob; KHODAYARI, Ali

    2007-01-01

    Oxidation of series of various primary and secondary alcohols to corresponding carbonyl compounds with ammonium persulfate in aqueous media was described. No over oxidation of primary alcohols to carboxylic acids and secondary alcohols to esters was observed. Under such conditions benzoin was converted to benzoic acid.

  12. New synthetic method and properties of ammonium dinitramide (ADN)

    Energy Technology Data Exchange (ETDEWEB)

    Hatano, H.; Onda, T.; Shi Ino, K.; Kiname, S.I. [Technical Center, Hosoya Kako, Osawa (Japan); Miyazaki, S.; Suzuki, S. [Research et Development Center, Nissan Motor Co, Saitama (Japan)

    1996-12-31

    Ammonium dinitramide (ADN) is one of the energetic materials, its hazard, however, has never been presented yet. In this paper, new synthetic method of ADN and its properties are contained. It has been found out that ADN has little hazard and is a safe energetic compound. (authors) 4 refs.

  13. 75 FR 14082 - Ammonium Salts of Fatty Acids (C8

    Science.gov (United States)

    2010-03-24

    ... diet of humans, animals, and plants and currently have Food and Drug Administration and EPA approved.../kg/day (6 times the limit dose of 1,000 mg/kg/day) on days 2 to 13 of pregnancy and musculo-skeletal... plants. Ammonium salts of fatty acid are not likely to persist in the environment and are expected to...

  14. Increase of water resistance of ammonium nitrate explosives

    Directory of Open Access Journals (Sweden)

    Zulkhair Mansurov

    2012-03-01

    Full Text Available Developed a method of kapsulating of ammonium nitrate with liquid paraffin increase finding explosives in water for 60 minutes. Placing explosives in the plastic shell, the explosive was, as in standing or running water during the day. When conducting field tests failures were absent.

  15. Characterization of ammonium polyuranate powders from a continuous precipitator

    Energy Technology Data Exchange (ETDEWEB)

    Oolman, T.

    1979-01-01

    Ammonium polyuranate powders produced in a continuous, well-mixed precipitator were characterized by means of electron microscopy. The powders were qualitatively analyzed with the scanning electron microscope and the elementary crystallites were quantivatively analyzed with the transmission electron microscope. The results were fit to a kinetic theory of continuous precipitation. A phase analysis was also preformed by x-ray powder diffraction.

  16. Synthetic receptors for ammonium ions using dynamic combinatorial chemistry

    NARCIS (Netherlands)

    Hamieh, Saleh

    2015-01-01

    The general topic of this dissertation is the development of synthetic receptors for organic ammonium ions in near physiological conditions using disulfide dynamic combinatorial chemistry (DCC). Chapter 1 explains the importance of this development and the associated difficulties when using the conv

  17. Carboxylates and the uptake of ammonium by excised maize roots

    NARCIS (Netherlands)

    Breteler, H.

    1975-01-01

    The effect of carboxylates (organic acid anions) on NH 4 uptake was studied by changing the carboxylate level of roots prior to uptake experi ments. Succinate was the most effective stimulator of ammonium uptake. The oxocarboxylates (α-oxoglutarate, oxaloacetate and

  18. Treating leachate mixture with anaerobic ammonium oxidation technology

    Institute of Scientific and Technical Information of China (English)

    ZHANG Hong-guo; ZHOU Shao-qi

    2006-01-01

    Large amounts of ammonium and a low content of biodegradable chemical oxygen demand(COD) are contained in leachate from aged landfills, together with the effluent containing high concentration of nitric nitrogen after biochemical treatment.Treatment effect of anaerobic ammonium oxidation (anammox) process on the mixture of the leachate and its biochemical effluent was investigated. The results show that the average removal efficiencies of ammonium, nitric nitrogen and total nitrogen are 87.51%,74.95% and 79.59%, respectively, corresponding to the average ratio of removed nitric nitrogen to ammonium, i.e. 1.14 during the steady phase of anammox activity. The mean removal efficiency of COD is only 24.01% during the experimental period. The demand of total phosphorous for the anammox process is unobvious. Especially, the alkalinity and pH value of the effluent are close to those of the influent during the steady phase of anammox activity. In addition, it is demonstrated that the status of the anammox bioreactor can be indicated by the alkalinity and pH value during the course of the experiment. The anammox bioreactor has shown potential for nitrogen removal in the leachate mixture. However, COD and total phosphorous in the leachate mixture need further treatment for removal efficiencies of COD and total phosphorous are not good in the anammox bioreactor.

  19. Growth features of ammonium hydrogen -tartrate single crystals

    Indian Academy of Sciences (India)

    G Sajeevkumar; R Raveendran; B S Remadevi; Alexander Varghese Vaidyan

    2004-08-01

    Ammonium hydrogen -tartrate (-AHT) single crystals were grown in silica gel. The growth features of these crystals with variation of parameters like specific gravity of the gel, gel pH, acid concentrations, concentration of the feed solution and gel age were studied in detail.

  20. Global modeling of nitrate and ammonium aerosols using EQSAM3

    Science.gov (United States)

    Xu, L.; Penner, J. E.

    2009-12-01

    Atmospheric aerosols, particles suspending in air, are important as they affect human health, air quality, and visibility as well as climate. Sulfate, nitrate, ammonium, chloride and sodium are among the most important inorganic aerosol species in the atmosphere. These compounds are hygroscopic and absorb water under almost all ambient environmental conditions. The uptake of water alters the aerosol size, and causes water to become the constituent with the largest atmospheric aerosol mass, especially when the aerosols grow into fog, haze or clouds. Furthermore, several global model studies have demonstrated that rapid increases in nitrogen emissions could produce enough nitrate in aerosols to offset the expected decline in sulfate forcing by 2100 for the extreme IPCC A2 scenario (Bauer et al., 2007). Although nitrate and ammonium were identified as significant anthropogenic sources of aerosols by a number of modeling studies, most global aerosol models still exclude ammonium-nitrate when the direct aerosol forcing is studied. In this study, the computationally efficient equilibrium model, EQSAM3, is incorporated into the UMICH-IMPACT-nitrate model using the hybrid dynamical solution method (Feng and Penner, 2007). The partitioning of nitrate and ammonium along with the corresponding water uptake is evaluated by comparing the model to the EQUISOLVE II method used in Feng and Penner (2007). The model is also evaluated by comparison with the AERONET data base and satellite-based aerosol optical depths.

  1. Profiling the origin of ammonium nitrate: proof-of-principle

    NARCIS (Netherlands)

    Carol-Visser, J.; Farmache, M.A.; Heijden, A.E.D.M. van der

    2011-01-01

    In many Improvised Explosive Devices (IEDs) the main charge consists of ammonium nitrate (AN). For forensic reasons, screening for the origin of AN is of importance. By assessing specifi c characteristics, diff erent AN batches can be profi led, in this way providing extra information which could le

  2. Influence of alkyl group of imidazolinyl-quaternary-ammonium-salt on corrosion inhibition efficiency

    Institute of Scientific and Technical Information of China (English)

    SHI Shun-cun; WANG Xue-ye; YI Ping-gui; CAO Chen-zhong; DENG Tong-tong; SU Jie-shu

    2006-01-01

    The action between imidazolinyl-quaternary-ammonium-salt(IQAS) molecule and Fe atom was studied,and the influence of the alkyl group connected with N atom of imidazoline ring on corrosion inhibition efficiency was explored. Quantum chemical methods, HF/6- 31 G and HF/Lan L2 dz, were applied successively to calculate the parameters such as front molecular orbit energy of IQAS Ⅰ-Ⅳ and chemical adsorption for IQAS Ⅰ-Ⅳ and Fe atom.The corrosion inhibition efficiency was measured with the weight loss method of carbon steel samples in acidic solution and oil field sewage. Based on the theoretical analyses and experimental results, it is concluded that N-Fe coordination bond is formed between IQAS molecule and Fe atom, corrosion inhibition efficiency is decreased in the following order(from large to small): IQAS Ⅳ, IQAS Ⅲ, IQAS Ⅱ , IQAS Ⅰ.

  3. Entangled Uranyl Organic Frameworks with (10,3)-b Topology and Polythreading Network: Structure, Luminescence, and Computational Investigation.

    Science.gov (United States)

    Liu, Chao; Gao, Chao-Ying; Yang, Weiting; Chen, Fang-Yuan; Pan, Qing-Jiang; Li, Jiyang; Sun, Zhong-Ming

    2016-06-06

    Two 3D uranyl organic frameworks (UOFs) with entangled structures, (HPhen)2[(UO2)2L2]·4.5H2O (1) and [(UO2)3(H2O)4L2]·6H2O (2), were synthesized using a rigid tripodal linker (4,4',4″-(phenylsilanetriyl)tribenzoic acid, H3L). Compound 1 represents a 2-fold interpenetrating UOF with the unique (10,3)-b topology. Compound 2 is composed of three interlocked sets of identical singlet networks and thus exhibits a rare 3D polythreading network with (3,4)-connected topology. These two compounds have been characterized by IR, UV-vis, and photoluminescent spectroscopy. A density functional theory (DFT) study on the model compounds of 1 and 2 shows good agreement of structural parameters and U═O stretching vibrational frequencies with experimental data. The experimentally measured absorption bands were well reproduced by the time-dependent DFT calculations.

  4. Experimental Results for Direct Electron Irradiation of a Uranyl Sulfate Solution: Bubble Formation and Thermal Hydraulics Studies

    Energy Technology Data Exchange (ETDEWEB)

    Chemerisov, Sergey [Argonne National Lab. (ANL), Argonne, IL (United States); Gromov, R. [Argonne National Lab. (ANL), Argonne, IL (United States); Makarashvili, Vakhtang [Argonne National Lab. (ANL), Argonne, IL (United States); Heltemes, Thad [Argonne National Lab. (ANL), Argonne, IL (United States); Sun, Zaijing [Argonne National Lab. (ANL), Argonne, IL (United States); Wardle, Kent E. [Argonne National Lab. (ANL), Argonne, IL (United States); Bailey, James [Argonne National Lab. (ANL), Argonne, IL (United States); Stepinski, Dominique [Argonne National Lab. (ANL), Argonne, IL (United States); Jerden, James [Argonne National Lab. (ANL), Argonne, IL (United States); Vandegrift, George F. [Argonne National Lab. (ANL), Argonne, IL (United States)

    2015-01-30

    In support of the development of accelerator-driven production of fission product Mo-99 as proposed by SHINE Medical Technologies, a 35 MeV electron linac was used to irradiate depleted-uranium (DU) uranyl sulfate dissolved in pH 1 sulfuric acid at average power densities of 6 kW, 12 kW, and 15 kW. During these irradiations, gas bubbles were generated in the solution due to the radiolytic decomposition of water molecules in the solution. Multiple video cameras were used to record the behavior of bubble generation and transport in the solution. Seven six-channel thermocouples were used to record temperature gradients in the solution from self-heating. Measurements of hydrogen and oxygen concentrations in a helium sweep gas were recorded by a gas chromatograph to estimate production rates during irradiation. These data are being used to validate a computational fluid dynamics (CFD) model of the experiment that includes multiphase flow and a custom bubble injection model for the solution region.

  5. Grain-Size Based Additivity Models for Scaling Multi-rate Uranyl Surface Complexation in Subsurface Sediments

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Xiaoying; Liu, Chongxuan; Hu, Bill X.; Hu, Qinhong

    2016-07-31

    The additivity model assumed that field-scale reaction properties in a sediment including surface area, reactive site concentration, and reaction rate can be predicted from field-scale grain-size distribution by linearly adding reaction properties estimated in laboratory for individual grain-size fractions. This study evaluated the additivity model in scaling mass transfer-limited, multi-rate uranyl (U(VI)) surface complexation reactions in a contaminated sediment. Experimental data of rate-limited U(VI) desorption in a stirred flow-cell reactor were used to estimate the statistical properties of the rate constants for individual grain-size fractions, which were then used to predict rate-limited U(VI) desorption in the composite sediment. The result indicated that the additivity model with respect to the rate of U(VI) desorption provided a good prediction of U(VI) desorption in the composite sediment. However, the rate constants were not directly scalable using the additivity model. An approximate additivity model for directly scaling rate constants was subsequently proposed and evaluated. The result found that the approximate model provided a good prediction of the experimental results within statistical uncertainty. This study also found that a gravel-size fraction (2 to 8 mm), which is often ignored in modeling U(VI) sorption and desorption, is statistically significant to the U(VI) desorption in the sediment.

  6. Adsorption characteristics of uranyl ions onto micelle surface for treatment of radioactive liquid wastes by micelle enhanced ultrafiltration technique

    Energy Technology Data Exchange (ETDEWEB)

    Lee, K. W.; Choi, W. K.; Jeong, K. H.; Lee, D. K.; Jeong, K. J. [KAERI, Taejon (Korea, Republic of)

    2001-10-01

    The objective of this investigation is to establish the rejection behavior of uranium bearing waste water by micelle enhanced ultrafiltration technique. An extensive experimental investigation was conducted with uranium only and uranium in the presence of electrolyte, utilizing ultrasfiltration stirred cell. The effects of experimental parameters such as solution pH and concentration of uranium on rejection were examined from the change of micelle concentration. The rejection dependence of the uranium was found to be a function of pH and uranium to surfactant concentration ratio. Over 95% removal was observed at pH 3 {approx} 5 and SDS concentration of 40 mM. In the presence of electrolytes, the rejection of uranium was observed to decrease significantly, the addition of cobalt ion showed more reduction than that obtained by presence of sodium and cesium ions on rejection of uranium. The rejection behavior was explained in terms of apparent distribution constants. The rejection efficiencies of uranyl ions was significantly affected by the chemical species of the given system. For all cases, the rejection was highly dependent on uranium complex species.

  7. Nanoscale UO{sub 2} and novel complex U(IV)-sulphate phase formation from electrolytically reduced uranyl sulphate solutions

    Energy Technology Data Exchange (ETDEWEB)

    Gil, D.; Malmbeck, R.; Spino, J.; Fanghaenel, T. [European Commission, Joint Research Centre, Inst. for Transuranium Elements, Karlsruhe (Germany); Dinnebier, R. [Max Planck Inst. for Solid State Research, Stuttgart (Germany)

    2010-07-01

    Three different processes have been explored to determine the ranges of U-concentration and acidity (pH-value) for nanocrystalline U{sub 2+x} precipitation from electrolytically reduced uranyl sulphate solutions. Precipitation of U{sub 2+x} nanoparticles aggregates was found to occur only in the narrow range of pH {proportional_to} 4.5 to 5 and for U-concentrations of {proportional_to} 10{sup -6} to 10{sup -7} M. The solid phase crystallized with the typical UO{sub 2}-fcc structure and with a crystallite size {<=} 3 nm. The average aggregate size was mostly {<=} 80 nm. At higher U-concentrations, ranging from [U] {proportional_to} 10{sup -1} M at pH {proportional_to} 1.5 to [U] {proportional_to} 5 x 10{sup -4} M at pH {proportional_to} 4.9, formation of microscale precipitates of a novel complex U(IV)-sulphate phase occurred, which was characterized by SEM/EDX-WDX, ICP-OES and XRD-powder diffraction. The crystal structure was identified with an orthorhombic cell (space group Cmca), with the following lattice parameters: a = 1.974(0)(2) nm, b = 1.3336(2) nm and c = 2.0643(2) nm. Further composition analyses indicated a basic sulphate hydrate of the type Na{sub 3}U(SO{sub 4}){sub 3}(OH).nH{sub 2}O. (orig.)

  8. Toward equatorial planarity about uranyl: synthesis and structure of tridentate nitrogen-donor {UO2}2+ complexes.

    Science.gov (United States)

    Copping, Roy; Jeon, Byoungseon; Pemmaraju, C Das; Wang, Shuao; Teat, Simon J; Janousch, Markus; Tyliszczak, Tolek; Canning, Andrew; Grønbech-Jensen, Niels; Prendergast, David; Shuh, David K

    2014-03-01

    The reaction of UO2Cl2·3THF with the tridentate nitrogen donor ligand 2,6-bis(2-benzimidazolyl)pyridine (H2BBP) in pyridine leads to the formation of three different complexes: [(UO2)(H2BBP)Cl2] (1), [(UO)2(HBBP)(Py)Cl] (2), and [(UO2)(BBP)(Py)2] (3) after successive deprotonation of H2BBP with a strong base. Crystallographic determination of 1-3 reveals that increased charge through ligand deprotonation and displacement of chloride leads to equatorial planarity about uranyl as well as a more compact overall coordination geometry. Near-Edge X-ray Absorption Fine Structure (NEXAFS) spectra of 1-3 at the U-4d edges have been recorded using a soft X-ray Scanning Transmission X-ray Microscope (STXM) and reveal the uranium 4d5/2 and 4d3/2 transitions at energies associated with uranium in the hexavalent oxidation state. First-principles Density Functional Theory (DFT) electronic structure calculations for the complexes have been performed to determine and validate the coordination characteristics, which correspond well to the experimental results.

  9. Maximizing ammonium nitrogen removal from solution using different zeolites.

    Science.gov (United States)

    Penn, Chad J; Warren, Jason G; Smith, Savannah

    2010-01-01

    Zeolite minerals are ideal for removing ammonium nitrogen (NH4(+)-N) from animal wastes, leachates, and industrial effluents. The objectives of this study were to compare NH4+ removal and kinetics among several commercially available zeolites under various conditions and determine if calorimetry could provide information regarding kinetics of NH4+ removal. Ammonium sorption onto potassium (K) saturated zeolites was compared using synthetic vs. natural swine effluent and with either traditional batch-shaken system or a "tea bag" approach in which zeolites were contained in a mesh sack and suspended in a solution of swine effluent. Ammonium sorption was measured at four retention times using a flow-through system, and the resulting heat response was measured using isothermal calorimetry. Ammonium removal was not significantly different in synthetic vs. natural swine effluent. Ammonium removal was lower in batch-stirred compared to batch-shaken systems, suggesting that diffusion between particles was rate-limiting in the former system. Flow-through cells possessing contact times > 100 s displayed greater NH4+ sorption than batch systems, suggesting that maintaining high NH4+ concentration in solution, removal of exchange products, and sufficient reaction time are critical to maximizing NH4+ removal by zeolites. Within 100 s after NH4+ addition, endothermic heat responses indicated that NH4(+)-K+ exchange had peaked; this was followed by significant heat rate reduction for 50 min. This confirmed findings of an initial fast NH4(+)-K+ exchange followed by a slower one and suggests the 100-s period of rapid reaction is an indicator of the minimum flow through retention time required to optimize NH4+ sorption to zeolites used in this study.

  10. Recycle use of magnesium ammonium phosphate to remove ammonium nitrogen from rare-earth wastewater.

    Science.gov (United States)

    Huang, H M; Xiao, X M; Yan, B

    2009-01-01

    This paper presents a recycle MAP process (magnesium ammonium phosphate) to remove NH4-N from a typical rare-earth wastewater. The optimum conditions for the MAP precipitation and recycle use of the MAP with a newly-designed process were investigated in laboratory. The results showed that the pH value and dosages of P (phosphate) and Mg reagents have a significant influence on NH4-N removal, with a maximum removal efficiency of 99.4% at the conditions of pH=9 and Mg:N:P molar ratio=1.2:1:1.2. In the process of recycle use of the MAP, adding some HCl to dissolve MAP decomposition residues could effectively enhance NH4-N removal. The NH4-N removal efficiency reached 99.6% by adding an HCl amount of H+:OH- molar ratio=0.8 into the reused MAP decomposition residues, whereas the NH4-N removal efficiency without addition of HCl was only 96.4%. Moreover, the residual PO4-P from the end of reaction was recovered and the optimum recovery efficiency was achieved at a Mg:P molar ratio=6 and pH=10. Under these optimum conditions, the residual NH4-N and PO4-P concentrations in the treated wastewater, through 6 times of the recycling, were less than 15 mg/L and 1 mg/L, respectively. On the basis of this, an economic evaluation of the recycling MAP was made, and this recycle process could save 48.6% cost used in the chemicals for treating per cubic meter of the rare-earth wastewater, compared to the conventional MAP process.

  11. Complex electronic waste treatment - An effective process to selectively recover copper with solutions containing different ammonium salts.

    Science.gov (United States)

    Sun, Z H I; Xiao, Y; Sietsma, J; Agterhuis, H; Yang, Y

    2016-11-01

    Recovery of valuable metals from electronic waste has been highlighted by the EU directives. The difficulties for recycling are induced by the high complexity of such waste. In this research, copper could be selectively recovered using an ammonia-based process, from industrially processed information and communication technology (ICT) waste with high complexity. A detailed understanding on the role of ammonium salt was focused during both stages of leaching copper into a solution and the subsequent step for copper recovery from the solution. By comparing the reactivity of the leaching solution with different ammonium salts, their physiochemical behaviour as well as the leaching efficiency could be identified. The copper recovery rate could reach 95% with ammonium carbonate as the leaching salt. In the stage of copper recovery from the solution, electrodeposition was introduced without an additional solvent extraction step and the electrochemical behaviour of the solution was figured out. With a careful control of the electrodeposition conditions, the current efficiency could be improved to be 80-90% depending on the ammonia salts and high purity copper (99.9wt.%). This research provides basis for improving the recyclability and efficiency of copper recovery from such electronic waste and the whole process design for copper recycling.

  12. Glyoxal uptake on ammonium sulphate seed aerosol: reaction products and reversibility of uptake under dark and irradiated conditions

    Directory of Open Access Journals (Sweden)

    M. M. Galloway

    2008-12-01

    Full Text Available Chamber studies of glyoxal uptake onto neutral ammonium sulphate aerosol were performed under dark and irradiated conditions to gain further insight into processes controlling glyoxal uptake onto ambient aerosol. Organic fragments from glyoxal dimers and trimers were observed within the aerosol under dark and irradiated conditions; glyoxal oligomer formation and overall organic growth were found to be reversible under dark conditions. Analysis of high-resolution time-of-flight aerosol mass spectra provides evidence for irreversible formation of carbon-nitrogen (C-N compounds in the aerosol. These compounds are likely to be imidazoles formed by reaction of glyoxal with the ammonium sulphate seed. To the authors' knowledge, this is the first time C-N compounds resulting from condensed phase reactions with ammonium sulphate seed have been detected in aerosol. Organosulphates were not detected under dark conditions. However, active oxidative photochemistry, similar to that found in cloud processing, was found to occur within aerosol during irradiated experiments. Organosulphates, carboxylic acids, and organic esters were identified within the aerosol. Our study suggests that both C-N compound formation and photochemical processes should be considered in models of secondary organic aerosol formation via glyoxal.

  13. Electrochemical oxidation of quaternary ammonium electrolytes : Unexpected side reactions in organic electrochemistry

    NARCIS (Netherlands)

    Nouri Nigjeh, Eslam; de Vries, Marcel; Bruins, Andries P.; Bischoff, Rainer; Permentier, Hjalmar P.

    2012-01-01

    Quaternary ammonium salts are among the most widely used electrolytes in organic electrochemistry, but there is little known about their unwanted side oxidation reactions. We have, therefore, studied the constant potential oxidation products of quaternary ammonium electrolytes using mass spectrometr

  14. Antibacterial activity of reactive quaternary ammonium compounds in solution and in nonleachable coatings

    NARCIS (Netherlands)

    Gozzelino, G.; Romero Tobar, D.E.; Chaitiemwong, N.; Hazeleger, W.C.; Beumer, R.R.

    2011-01-01

    Antibacterial polymers suitable for coating applications without leaching of the biocidal component have been obtained by UV copolymerization of acrylic resins with acrylic monomers containing quaternary ammonium moieties. Suitable reactive biocides, based on quaternary ammonium monomers (QAMs), end

  15. Reduction of Nitrate to Ammonium in Selected Paddy Soil of China

    Institute of Scientific and Technical Information of China (English)

    YINSHIXUE; SHENQIRONG; 等

    1998-01-01

    Three paddy soils soils were examined for their capacities of dissimilatory reduction of nitrate to ammonium (DRNA). 15N-labelled KNO3 was added at the rate of 100mg N kg-1 ,Either glucose or rice straw powder was incorporated at the rate of 1.0 or 2.0 mg C kg-1 respectively,Three treatments were designed to keep the soil saturated with water: A) a 2-cm water layer on soil surface (with beaker mouth open);B) a 2-cm water layer and a 1-cm liquild paraffin layer(with beaker mouth open);and C)water saturated under O2-free Ar atmosphere.The soils were inculated at 28 ℃ for 5 days,There eas alomst no 15N-labelled NH4+-N detected in Treatment A.However,there was 1.4 to 3.4mg N kg-1 15N-labelled NH4+-n in Treatment B and 2.1 to 13.8 mg N kg-1 in reatment C.Glucose was more effective than straw powder in ammonium production.Because there was sufficient amount of non-labelled NH4+-N in the original soils. 15N-labelled NH4+-N produced as such should be the result of dissimilatory reduction.Studies on microbial population showed that there were plenty of bacteria responisble for DRNA process(DRNA bacteria) in the soils examined,indicating that number of DNRA bacteia was not a limiting factor ammonium prodction.However,DRNA bacteria were inferior in number to denitrifiers.DRNA process in soil suspension seemed to start after 5 days of incubation.Glycerol and sodium succinate,thought both are readily available carbon sources to organisms,did not facilitate DNRA process.DRNA occurred only when glucose was available and at the C/NO3--N ratio of over 12 .It seemed that both availability and quality of the carbon sources affected DRNA.

  16. Effective immobilisation of a metathesis catalyst bearing an ammonium-tagged NHC ligand on various solid supports

    Directory of Open Access Journals (Sweden)

    Krzysztof Skowerski

    2016-01-01

    Full Text Available An ammonium-tagged ruthenium complex, 8, was deposited on several widely available commercial solid materials such as silica gel, alumina, cotton, filter paper, iron powder or palladium on carbon. The resulting catalysts were tested in toluene or ethyl acetate, and found to afford metathesis products in high yield and with extremely low ruthenium contamination. Depending on the support used, immobilised catalyst 8 shows also additional traits, such as the possibility of being magnetically separated or the use for metathesis and subsequent reduction of the obtained double bond in one pot.

  17. Kinetic of liquid-liquid extraction for uranyl nitrate and actinides (III) and lanthanides (III) nitrates by amide extractants; Cinetique d`extraction liquide-liquide du nitrate d`uranyle et des nitrates d`actinides (III) et de lanthanides (III) par des extractants a fonction amide

    Energy Technology Data Exchange (ETDEWEB)

    Toulemonde, V. [CEA Centre d`Etudes Nucleaires de Saclay, 91 -Gif-sur-Yvette (France)]|[CEA Centre d`Etudes de la Vallee du Rhone, 30 -Marcoule (France). Dept. d`Exploitation du Retraitement et de Demantelement

    1995-12-20

    The kinetics of liquid-liquid extraction by amide extractants have been investigated for uranyl nitrate (monoamide extractants), actinides (III) and lanthanides (III) nitrates (diamide extractants). The transfer of the metallic species from the aqueous phase to the organic phase was studied using two experimental devices: ARMOLLEX (Argonne Modified Lewis cell for Liquid Liquid Extraction) and RSC (Rotating Stabilized Cell). The main conclusions are: for the extraction of uranyl nitrate by DEHDMBA monoamide, the rate-controlling step is the complexation of the species at the interface of the two liquids. Thus, an absorption-desorption (according to Langmuir theory) reaction mechanism was proposed; for the extraction of actinides (III) and lanthanides (III) nitrates in nitric acid media by DMDBTDMA diamide, the kinetic is also limited by interfacial reactions. The behavior of Americium and Europium is very similar as fare as their reaction kinetics are concerned. (author). 89 refs.

  18. 21 CFR 520.310 - Caramiphen ethanedisulfonate and ammonium chloride tablets.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 6 2010-04-01 2010-04-01 false Caramiphen ethanedisulfonate and ammonium chloride... § 520.310 Caramiphen ethanedisulfonate and ammonium chloride tablets. (a) Specifications. Each tablet contains 10 milligrams of 5st caramiphen ethanedisulfonate and 80 milligrams of ammonium chloride.1 1...

  19. 40 CFR 415.240 - Applicability; description of the ammonium chloride production subcategory.

    Science.gov (United States)

    2010-07-01

    ... ammonium chloride production subcategory. 415.240 Section 415.240 Protection of Environment ENVIRONMENTAL... SOURCE CATEGORY Ammonium Chloride Production Subcategory § 415.240 Applicability; description of the ammonium chloride production subcategory. The provisions of this subpart are applicable to...

  20. 77 FR 21527 - Ammonium Nitrate From Russia: Correction to Notice of Opportunity To Request Administrative Review

    Science.gov (United States)

    2012-04-10

    ... International Trade Administration Ammonium Nitrate From Russia: Correction to Notice of Opportunity To Request... of the antidumping duty orders and inadvertently omitted Ammonium Nitrate from Russia, POR 5/2/2011-3... include the Ammonium Nitrate from Russia administrative review in the referenced notice. Dated: April...

  1. 77 FR 32669 - Ammonium Nitrate from Ukraine Institution of a Five-Year Review

    Science.gov (United States)

    2012-06-01

    ... COMMISSION Ammonium Nitrate from Ukraine Institution of a Five-Year Review AGENCY: United States... determine whether revocation of the antidumping duty order on ammonium nitrate from Ukraine would be likely... ammonium nitrate from Ukraine (66 FR 47451). Following the five-year reviews by Commerce and the...

  2. The system uranyl nitrate-dietyl ether-water. Extraction by water in spray and packed columns from uranyl nitrate-either solutions; El sistema nitrato de uranilo-eter dietilico-agua, extraccion de nitrato de uranilo con agua a partir de disoluciones etereas en columnas de pulverizacion y de relleno

    Energy Technology Data Exchange (ETDEWEB)

    Perez Luina, A.; Gutierrez Jodra, L.

    1960-07-01

    This paper is a continuation of the one published in Chemical Engineering Progress. Symposium Series, 50, n. 12, 127 (1954). New runs for spray columns, are given and other concentrations in uranyl nitrate for the packed columns. New correlations for the overall H.T.U. are also given. The individual H.T.U. have been grapycally calculated and show that the film resistances have similar values, being independent of the concentration of the ether phase. (Author) 24 refs.

  3. Modulation of the Structure and Properties of Uranyl Ion Coordination Polymers Derived from 1,3,5-Benzenetriacetate by Incorporation of Ag(I) or Pb(II).

    Science.gov (United States)

    Thuéry, Pierre; Harrowfield, Jack

    2016-07-01

    Reaction of uranyl nitrate with 1,3,5-benzenetriacetic acid (H3BTA) in the presence of additional species, either organic bases or their conjugate acids or metal cations, has provided 12 new crystalline complexes, all but one obtained under solvo-hydrothermal conditions. The complexes [C(NH2)3][UO2(BTA)]·H2O (1) and [H2NMe2][UO2(BTA)] (2) crystallize as one- or two-dimensional (1D or 2D) assemblies, respectively, both with uranyl tris-chelation by carboxylate groups and hydrogen-bonded counterions but different ligand conformations. One of the bound carboxylate units is replaced by chelating 1,10-phenanthroline (phen) or 3,4,7,8-tetramethyl-1,10-phenanthroline (Me4phen) in the complexes [(UO2)3(BTA)2(phen)3]·4H2O (3) and [(UO2)3(BTA)2(Me4phen)3]·NMP·3H2O (4) (NMP = N-methyl-2-pyrrolidone), which are a 2D network with honeycomb topology and a 1D polymer, respectively. With silver(I) cations, [UO2Ag(BTA)] (5), a three-dimensional (3D) framework in which the ligand assumes various chelating/bridging coordination modes, and the aromatic ring is involved in Ag(I) bonding, is obtained. A series of seven heterometallic complexes results when lead(II) cations and N-chelating molecules are both present. The complexes [UO2Pb(BTA)(NO3)(bipy)] (6) and [UO2Pb2(BTA)2(bipy)2]·3H2O (7), where bipy is 2,2'-bipyridine, crystallize from the one solution, as 1D and 2D assemblies, respectively. The two 1D coordination polymers [UO2Pb(BTA)(HCOO)(phen)] (8 and 9), again obtained from the one synthesis, provide an example of coordination isomerism, with the formate anion bound either to lead(II) or to uranyl cations. Another 2D architecture is found in [(UO2)2Pb2(BTA)2(HBTA)(H2O)2(phen)2]·2H2O (10), which provides a possible example of a Pb-oxo(uranyl) "cation-cation" interaction. While [UO2Pb(BTA)(HCOO)0.5(NO3)0.5(Me2phen)] (11), where Me2phen is 5,6-dimethyl-1,10-phenanthroline, is a 1D assembly close to those in 6 and 8, [UO2Pb2(BTA)2(Me4phen)2] (12), obtained together with

  4. Anaerobic ammonium oxidation, denitrification and dissimilatory nitrate reduction to ammonium in the East China Sea sediment

    Directory of Open Access Journals (Sweden)

    G. D. Song

    2013-03-01

    Full Text Available Benthic nitrogen transformation pathways were investigated in the sediment of the East China Sea in June of 2010 using the 15N isotope pairing technique. Slurry incubations indicated that denitrification, anammox and dissimilatory nitrate reduction to ammonium (DNRA as well as nitrate release by nitrate storing organisms occurred in the East China Sea sediments. These four processes did not exist independently, the nitrate release therefore diluted the 15N labeling fraction of NO3−, a part of the 15NH4+ derived from DNRA also formed 30N2 via anammox. Therefore current methods of rate calculations led to over and underestimations of anammox and denitrification respectively. Following the procedure outlined in Thampdrup and Dalsgaard (2002, denitrification rates were slightly underestimated by on average 6% without regard to the effect of nitrate release, while this underestimation could be counteracted by the presence of DNRA. On the contrary, anammox rates calculated from 15NO3− experiment were significantly overestimated by 42% without considering nitrate release. In our study this overestimation could only be compensated 14% by taking DNRA into consideration. In a parallel experiment amended with 15NH4+ + 14NO3−, anammox rates were not significantly influenced by DNRA due to the high background of 15NH4+ addition. Excluding measurements in which bioirrigation was present, integrated denitrification rates decreased from 10 to 4 mmol N m−2 d−1 with water depth, while integrated anammox rates increased from 1.5 to 4.0 mmol N m−2 d−1. Consequently, the relative contribution of anammox to the total N-loss increased from 13% at the shallowest site near the Changjiang estuary to 50% at the deepest site on the outer shelf. This study represents the first time in which anammox has been demonstrated to play a significant role in benthic nitrogen cycling in the East China Sea sediment, especially on the outer shelf. N

  5. UO₂²⁺ uptake by proteins: understanding the binding features of the super uranyl binding protein and design of a protein with higher affinity.

    Science.gov (United States)

    Odoh, Samuel O; Bondarevsky, Gary D; Karpus, Jason; Cui, Qiang; He, Chuan; Spezia, Riccardo; Gagliardi, Laura

    2014-12-17

    The capture of uranyl, UO2(2+), by a recently engineered protein (Zhou et al. Nat. Chem. 2014, 6, 236) with high selectivity and femtomolar sensitivity has been examined by a combination of density functional theory, molecular dynamics, and free-energy simulations. It was found that UO2(2+) is coordinated to five carboxylate oxygen atoms from four amino acid residues of the super uranyl binding protein (SUP). A network of hydrogen bonds between the amino acid residues coordinated to UO2(2+) and residues in its second coordination sphere also affects the protein's uranyl binding affinity. Free-energy simulations show how UO2(2+) capture is governed by the nature of the amino acid residues in the binding site, the integrity and strength of the second-sphere hydrogen bond network, and the number of water molecules in the first coordination sphere. Alteration of any of these three factors through mutations generally results in a reduction of the binding free energy of UO2(2+) to the aqueous protein as well as of the difference between the binding free energies of UO2(2+) and other ions (Ca(2+), Cu(2+), Mg(2+), and Zn(2+)), a proxy for the protein's selectivity over these ions. The results of our free-energy simulations confirmed the previously reported experimental results and allowed us to discover a mutant of SUP, specifically the GLU64ASP mutant, that not only binds UO2(2+) more strongly than SUP but that is also more selective for UO2(2+) over other ions. The predictions from the computations were confirmed experimentally.

  6. Sources et marché du sulfate d'ammonium Sources of and Market for Ammonium Sulfate

    Directory of Open Access Journals (Sweden)

    Loussouarn C.

    2006-11-01

    Full Text Available Engrais azoté le plus utilisé dans le monde jusqu'en 1970, le sulfate d'ammonium ne représente plus aujourd'hui que 4 % de la fertilisation azotée. Avec une teneur en azote de 21 % seulement, il a été peu à peu remplacé comme engrais universel par des produits plus concentrés, notamment l'urée et le nitrate d'ammonium. Obtenu pour plus de 40 % comme sous-produit dans la synthèse de monomères comme le caprolactame, l'acrylonitrile ou le méthacrylate de méthyle, et pour près de 10 % dans le traitement des gaz de cokerie, sa production dépend largement des développements du marché des fibres synthétiques, et, dans une moindre mesure, de la sidérurgie et de la métallurgie. Dans les pays développés, où la production est essentiellement fatale, le volume du marché est et sera plus fonction de la disponibilité du sulfate d'ammonium que de la demande ou de facteurs de marché; sa consommation ne résidera plus que dans des applications spécifiques pour lesquelles il sera bien adapté. Par contre, l'intérêt croissant pour compenser le déficit en soufre de certains sols, et les qualités agronomiques propres du sulfate d'ammonium laissent entrevoir la possibilité d'un essor de son utilisation dans certaines régions en voie de développernent. Ammonium sulfate was the most worldwide nitrogenous fertilizer used up to 1970. Today, it makes up only 4% of nitrogenous fertilization. With a nitrogen content of only 21%, it has gradually been replaced as a universal fertilizer by more concentrated products, particularly urea and ammonium nitrate. More than 40% of the ammonium sulfate is obtained as a by-product from the synthesis of monomers such as caprolactam, acrylonitrile or methyl methacrylate, and nearly 10% from coking gas processing. Its production depends extensively on the development of the market for synthetic fibers and, to a lesser extent, on the steel and metallurgical industries. In the industrialized countries

  7. Establishment of the conditions for the determination of the concentration of the uranyl ion in perchloric media by Fluorescence; Establecimiento de las condiciones para la determinacion de la concentracion del ion uranilo en medio perclorico por Fluorescencia

    Energy Technology Data Exchange (ETDEWEB)

    Contreras R, A.; Ordonez R, E.; Fernandez V, S.M. [ININ, 52045 Ocoyoacac, Estado de Mexico (Mexico)]. e-mail: contraida@yahoo.com.mx

    2004-07-01

    The influence of the p H is reported in the spectra of luminescence of the ion uranyl in sodium perchlorate 2M. The best spectra were observed to ph <3 that to neutral and basic p Hs this is explained by the present species. They were carried out four calibration curves for the uranyl in perchloric acid media, taking into account the area under the curve, the maximum height of two characteristic peaks of this ion, in those that one observes a better correlation with the maximum height of the peak located to 486.7 nm. (Author)

  8. Nitrate reduction by mixed iron(II-III) hydroxycarbonate green rust in the presence of phosphate anions: the key parameters influencing the ammonium selectivity.

    Science.gov (United States)

    Etique, Marjorie; Zegeye, Asfaw; Grégoire, Brian; Carteret, Cédric; Ruby, Christian

    2014-10-01

    The reduction of nitrate anions by a mixed Fe(II)-Fe(III) carbonated green rust (GR) in aqueous medium is studied as a function of the initial pH and the initial concentrations of iron, phosphate and nitrate. The influence of these parameters on the fraction of nitrate removed and the production of ammonium is investigated by the help of statistical experimental designs. The goal is to determine experimental conditions that maximize the fraction of NO3(-) removed and concomitantly minimize the production of NH4(+). Increasing the phosphate concentration relatively to the initial Fe(II) concentration inhibits the reduction of nitrate probably due to a surface saturation of the lateral sites of the GR crystals. The kinetics of the reaction is greatly enhanced by increasing the initial pH at 10.5, however it leads to a global increase of the NH4(+) production. A partial saturation of the surface sites by phosphate leads to a global decrease of selectivity of the reaction towards ammonium. The evolution of the ratio of the NH4(+) concentration to the Fe(II) concentration confirms that the NO3(-) species are only partially transformed into ammonium. Interestingly at an initial pH of 7.5, the selectivity of the reaction towards NH4(+) is often lower than ∼30%. The reduction of nitrate by carbonated GR differs from the behavior of other GRs incorporating Cl(-), F(-) and SO4(2-) anions that fully transform nitrate into ammonium. Finally, if GR is intended to be used during a passive water denitrification process, complementary dephosphatation and ammonium treatments should be considered.

  9. 2,6-Diiminopiperidin-1-ol: an overlooked motif relevant to uranyl and transition metal binding on poly(amidoxime) adsorbents

    Energy Technology Data Exchange (ETDEWEB)

    Kennedy, Zachary C.; Cardenas, Allan J.; Corbey, Jordan F.; Warner, Marvin G.

    2016-06-06

    Glutardiamidoxime, a structural motif on sorbents used in uranium extraction from seawater, was discovered to cyclize in situ at room temperature to 2,6-diimino-piperidin-1-ol in the presence of uranyl nitrate. The new diimino motif was also generated when exposed to competing transition metals Cu(II) and Ni(II). Multinuclear μ-O bridged U(VI), Cu(II), and Ni(II) complexes featuring bound diimino ligands were isolated. A Cu(II) complex with the historically relevant cyclic imide dioxime motif is also reported for structural comparison to the reported diimino complexes.

  10. Annual report of STACY operation in F.Y. 1997. 280mm thickness slab core {center_dot} 10% enriched uranyl nitrate solution

    Energy Technology Data Exchange (ETDEWEB)

    Onodera, Seiji; Sono, Hiroki; Hirose, Hideyuki [Japan Atomic Energy Research Inst., Tokai, Ibaraki (Japan). Tokai Research Establishment] [and others

    1998-06-01

    Fifty-three times critical experiments (run number R0104 to R0156) with STACY in NUCEF, were performed in F.Y. 1997. During these experiments, 10% enriched uranyl nitrate solution was used as fuel, and core configuration was 280mm thickness and 1.5m height slab core tank with various rectangular solid reflectors; ordinary or borated concrete, polyethylene and so on, to measure mainly reactivity worth by changes of reflecting material and its thickness. Operation data of STACY in F.Y. 1997 are summarized in this report. (author)

  11. Synthesis, antimicrobial activity of lamotrigine and its ammonium derivatives

    Indian Academy of Sciences (India)

    Yong Qian; Peng-Cheng Lv; Lei Shi; Rui-Qin Fang; Zhong-Cheng Song; Hai-Liang Zhu

    2009-07-01

    Antiepileptic drug lamotrigine and its thirteen ammonium salt complexes (4a-4m) were synthesized and characterized by IR, elemental analysis, 1H-NMR, and MS spectral methods. Many of the ammonium salts (4a-4m) were first reported. Furthermore, the crystal structure of compound 3 was determined by single crystal X-ray diffraction analysis. All these complexes were tested in vitro for their antibacterial activity (Bacillus subtilis, Staphylococcus aureus, Enterococus faecalis, Escherichia coli, Pseudomonas aeruginosa and Enterobacter cloacae). The results indicated that most of the complexes showed good antibacterial activity against Gram-positive (B. subtilis, S. aureus and S. faecalis), but showed mild, even inactive against Gram-negative bacterial strains.

  12. Thermal stability assessment of anti-explosive ammonium nitrate

    Institute of Scientific and Technical Information of China (English)

    Lijin Shen; Xuguang Wang

    2005-01-01

    The explosivity experiment of anti-explosive ammonium nitrate (AEAN) shows that the explosive characteristic of AEAN is eliminated. The adiabatic decompositions of ammonium nitrate and AEAN were investigated with an accelerating rate calorimeter (ARC). The curves of thermal decomposition temperature and pressure versus time, self-heating rate and pressure versus temperature for two systems were obtained. The kinetic parameters such as apparent activation energy and pre-exponential factor were calculated.The safety of AEAN was analyzed. It was indicated that AEAN has a higher thermal stability than AN. At the same time, it can be shown that the elimination of its explosive characteristic is due to the improvement on the thermal stability of AEAN.

  13. Anaerobic ammonium oxidation in a bioreactor treating slaughterhouse wastewater

    Directory of Open Access Journals (Sweden)

    V. Reginatto

    2005-12-01

    Full Text Available Ammonium oxidation was thought to be an exclusively aerobic process; however, as recently described in the literature, it is also possible under anaerobic conditions and this process was named ANAMMOX. This work describes the operation of a system consisting of a denitrifying reactor coupled to a nitrifying reactor used for removal of nitrogen from slaughterhouse wastewater. During operation of the denitrifying reactor an average nitrogen ammonium removal rate of 50 mg/Ld was observed. This biomass was used to seed a second reactor, operated in repeated fed batch mode, fed with synthetic medium specific to the growth of bacteria responsible for the ANAMMOX process. The nitrogen loading rate varied between 33 and 67 mgN/Ld and average nitrogen removal was 95% and 40%, respectively. Results of fluorescence in situ hybridization (FISH confirmed the presence of anammox-like microorganisms in the enriched biomass.

  14. Preparation of nanodispersed titania using stabilized ammonium nitrate melts

    KAUST Repository

    Raciulete, Monica

    2010-10-01

    An expedite one-step approach using simple precursors has been proposed to obtain metallic oxide compounds and exemplified by preparation of highly dispersed TiO2. The technique consists in heating to 400500 °C of molten ammonium nitrate stabilized with an organic nitrogen-containing compound (urea, melamine, ammonium oxalate) and containing dissolved metal salt precursor (TiOCl2). The crystallites of the resulting TiO2 demonstrated variable size and shape as a function of stabilizer used. Their activity in photocatalytic oxidation of formic acid also depends on the nature of the stabilizer. The catalysts as-prepared showed high photocatalytic performance, superior to that of the Degussa P25 reference. Nitrogen containing stabilizers play a double role of increasing the process safety and modifying the properties of the solid products. © 2010 Elsevier Inc. All rights reserved.

  15. The nitrogen Sternheimer antishielding factor in the ammonium ion

    Science.gov (United States)

    Fowler, P. W.; Kelly, H. M.; Brown, R. J. C.

    1993-12-01

    Coupled Hartree-Fock calculations in various basis sets yield values in the range 6.7 to 6.8 for the Sternheimer antishielding factor (1 - γ ∞) of the nitrogen nucleus in the ammonium ion. These are in substantial agreement with the value of 9 that is obtained from a model of measured relaxation times in solid ammonium chloride when allowance is made for effects of the crystalline environment on the chloride ion Sternheimer antishielding factor. Other experimental estimates of the nitrogen Sternheimer factor are discussed. The new value is used to derive cation field gradients from measured quadrupole coupling constants in solid NH 4ReO 4 and NH 4IO 4.

  16. Ab initio study of the mechanism for photoinduced Yl-oxygen exchange in uranyl(VI) in acidic aqueous solution.

    Science.gov (United States)

    Réal, Florent; Vallet, Valérie; Wahlgren, Ulf; Grenthe, Ingmar

    2008-09-03

    The mechanism for the photochemically induced isotope-exchange reaction U(17/18)O2(2+)(aq) + H2(16)O U(16)O2(2+)(aq) + H2(17/18)O has been studied using quantum-chemical methods. There is a dense manifold of states between 22,000 and 54,000 cm(-1) that results from excitations from the sigma(u) and pi(u) bonding orbitals in the (1)Sigma(g)(+) ground state to the nonbonding f(delta) and f(phi) orbitals localized on uranium. On the basis of investigations of the reaction profile in the (1)Sigma(g)(+) ground state and the excited states (3)Delta(g) (the lowest triplet state) and (3)Gamma(g) (one of the several higher triplet states), the latter two of which have the electron configurations sigma(u)f(delta) and pi(u)f(phi), respectively, we suggest that the isotope exchange takes place in one of the higher triplet states, of which the (3)Gamma(g) state was used as a representative. The geometries of the luminescent (3)Delta(g) state, the lowest in the sigma(u)f(delta,phi) manifold (the "sigma" states), and the (1)Sigma(g)(+) ground state are very similar, except that the bond distances are slightly longer in the former. This is presumably a result of transfer of a bonding electron to a nonbonding f orbital, which makes the excited state in some respects similar to uranyl(V). As is the case for all of the states of the pi(u)f(delta,phi) manifold (the "pi" states), the geometry of the (3)Gamma(g) state is very different from that of the (3)Delta(g) "sigma" state and has nonequivalent U-O(yl) distances of 1.982 and 1.763 A; in the (3)Gamma(g) state, the yl-exchange takes place by transfer of a proton or hydrogen from water to the more distant yl-oxygen. The activation barriers for proton/hydrogen transfer in the ground state and the (3)Delta(g) and (3)Gamma(g) states are 186, 219, and 84 kJ/mol, respectively. The relaxation energy for the (3)Gamma(g) state in the solvent after photoexcitation is -86 kJ/mol, indicating that the energy barrier can be overcome; the "pi

  17. Ammonium sulphate precipitation overestimates titres of anti-peptide antisera.

    Science.gov (United States)

    Roth, B; Barkas, T

    1984-01-01

    Precipitation by 50% final saturation of ammonium sulphate, a method commonly used to estimate titres and affinity constants of antibodies, was found consistently to overestimate the titre of anti-peptide antisera when compared with other antibody precipitants. The effect could not be attributed to non-IgG fractions, and similar overestimations were found when pure IgG was used. We suggest that the lower values represent a more physiologically relevant estimation.

  18. Recovering germanium from coal ash by chlorination with ammonium chloride

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    A new process of enriching germanium from coal ash was developed. The process involves in mixing the coal ash and ammonium chloride and then roasting the mixture to produce germanium chloride that is then absorbed by dilute hydrochloric acid and hydrolyzed to germanium oxide. The germanium recovery reached to 80.2% at the optimum condition: mass ratio of NH4Cl/coal ash is 0.15, roasting temperature 400℃ and roasting time 90 min.

  19. Proton- and ammonium- sensing by histaminergic neurons controlling wakefulness.

    Directory of Open Access Journals (Sweden)

    Yvgenij eYanovsky

    2012-04-01

    Full Text Available Orexinergic and histaminergic neurons in the posterior hypothalamus are involved in the control of arousal. Extracellular levels of acid /CO2 are fundamental physicochemical signals controlling wakefulness and breathing. Acidification excites orexinergic neurons like the chemosensory neurons in the brain stem. Hypercapnia induces c-Fos expression, a marker for increased neuronal activity, in the rat histaminergic tuberomamillary nucleus (TMN, but the mechanisms of this excitation are unknown. Acid-sensing ion channels (ASICs are gated by protons and also by ammonium. Recordings in rat brain slices revealed now that acidification within the physiological range (pH from 7.3 to 7.0 as well as ammonium chloride (5mM excite histaminergic neurons. We detected variable combinations of 4 known types of ASICs in single TMN neurons, along with the pharmacological properties of pH-induced current. At pH 7.0 however, activation of ASICs in TMN neurons was negligible. Block of type I metabotropic glutamate receptors abolished proton- but not ammonium- induced excitation. Mouse TMN neurons were identified within a novel HDC-Cre transgenic reporter mouse line. In contrast to the rat these lacked pH 7.0-induced excitation and showed only a minimal response to the mGluR I agonist DHPG (0.5µM. Ammonium-induced excitation was similar in mouse and rat. Thus glutamate, which is released by glial cells and orexinergic axons amplifies CO2/acid-induced arousal through the recruitment of the histaminergic system in rat but not in mouse. These results are relevant for the understanding of neuronal mechanisms controlling H+/CO2-induced arousal in hepatic encephalopathy and obstructive sleep apnoea. The new HDC-Cre mouse model will be a useful tool for studying the physiological and pathophysiological roles of the histaminergic system.

  20. Nanomodified vermiculite NMV - a new material for recycling ammonium nitrogen

    Science.gov (United States)

    Rama, Miradije; Laiho, Taina; Eklund, Olav; Lehto, Kirsi; Shebanov, Alex; Smått, Jan-Henrik

    2016-04-01

    Vermiculites ((Mg,Fe,Al)3(Al,Si)4O10(OH)24H2O) are naturally occurring minerals from hydromica group with a high cation exchange capacity and large surface area. Since vermiculite is a hydrated mineral, its structure can be changed with heat. In this study vermiculite samples were heated in an oven until the interlayer distance of them diminished from 14 Å to 11.7 Å. This method for improving vermiculites intake of ammonium ions by heating, is an invention made at the University of Turku. Nanomodified vermiculite (NMV) is able to absorb up to 4.7 wt% of ammonium. NMV can be used as an efficient filter and immobilizer of ammonium in different environments. NMV has been efficiently tested on waste water from a biogas plant, human urine, combustion experiments, industrial chimneys, excrements from farms etc. Ammonium doped vermiculite (ADV) is further developed for fertilizer use. Performed experiments have testified the usability of ADV as a fertilizer. At first step the NMV was processed with the reject water from a biogas plant, were it absorbed NH4+ into the lattice. At second, the ADV was used as nutrient source for garden plants. Geraniums and begonias were used as test plants of the work. Plant growth rate was evaluated based on plant weight. Results showed that significant increase of the growth of geraniums and of begonias were observed when comparing to those cultivations where plants have got normal fertilization. Moreover, ADV has been tested as a fertilizer in greenhouse experiments with spruces and pines. After five months, the weight of the plants that had grown in a substrate containing ADV was 10 times the weight of plants growing in the reference substrate.

  1. Europium, uranyl, and thorium-phenanthroline amide complexes in acetonitrile solution: an ESI-MS and DFT combined investigation.

    Science.gov (United States)

    Xiao, Cheng-Liang; Wang, Cong-Zhi; Mei, Lei; Zhang, Xin-Rui; Wall, Nathalie; Zhao, Yu-Liang; Chai, Zhi-Fang; Shi, Wei-Qun

    2015-08-28

    The tetradentate N,N'-diethyl-N,N'-ditolyl-2,9-diamide-1,10-phenanthroline (Et-Tol-DAPhen) ligand with hard-soft donor atoms has been demonstrated to be promising for the group separation of actinides from highly acidic nuclear wastes. To identify the formed complexes of this ligand with actinides and lanthanides, electrospray ionization mass spectrometry (ESI-MS) combined with density functional theory (DFT) calculations was used to probe the possible complexation processes. The 1 : 2 Eu-L species ([EuL2(NO3)](2+)) can be observed in ESI-MS at low metal-to-ligand ([M]/[L]) ratios, whereas the 1 : 1 Eu-L species ([EuL(NO3)2](+)) can be observed when the [M]/[L] ratio is higher than 1.0. However, ([UO2L(NO3)](+)) is the only detected species for the uranyl complexes. The [ThL2(NO3)2](2+) species can be observed at low [M]/[L] ratios; the 1 : 2 species ([ThL2(NO3)](3+)) and a new 1 : 1 species ([ThL(NO3)3](+)) can be detected at high [M]/[L] ratios. Collision-induced dissociation (CID) results showed that Et-Tol-DAPhen ligands can coordinate strongly with metal ions, and the coordination moieties remain intact under CID conditions. Natural bond orbital (NBO), molecular electrostatic potential (MEP), electron localization function (ELF), atoms in molecules (AIM) and molecular orbital (MO) analyses indicated that the metal-ligand bonds of the actinide complexes exhibited more covalent character than those of the lanthanide complexes. In addition, according to thermodynamic analysis, the stable cationic M-L complexes in acetonitrile are found to be in good agreement with the ESI-MS results.

  2. Study of magnetite as adsorbent material of uranyl ions; Estudo da magnetita como material adsorvedor de ions de uranilo

    Energy Technology Data Exchange (ETDEWEB)

    Leal, Roberto

    2006-07-01

    Magnetite, also known as iron ferrite, is a mineral iron and a natural magnet found in iron deposits. In addition to its magnetic intrinsic behavior, the magnetite has the capacity to remove the metallic ions from aqueous medium by adsorption phenomena. The strong magnetic character of magnetite distinguishes it from other adsorbent types, which it allows to be readily removed from solution by magnetic separation. In this work, uranium (VI) adsorption, as UO{sub 2}{sup 2+} ions, from nitric solution by synthetic magnetite was investigated. It was prepared by simultaneous precipitation process, adding a NaOH solution into a solution containing Fe{sup 2+} and Fe{sup 3+} ions. The synthetic magnetite, a black powder, has exhibited a strong magnetic response in presence of a magnetic field, without nevertheless becomes magnetic. This typical superparamagnetic behavior was confirmed by magnetization measurements. Adsorption parameters of UO{sub 2}{sup 2+} ions such as pH, the adsorbent dose, contact time and equilibrium isotherm were evaluated. Maximum uranium adsorption was observed in the pH 4.0-5.0 range. It was noticed that increase in magnetite dose increased the percent removal of uranium, but decreased the adsorption capacity of the magnetite. It was observed from the relation between adsorption and contact time that the removal has increased very fast with time, and achieved the equilibrium within 30 minutes. The results of equilibrium isotherm agreed well with the Langmuir model, and so the theoretical saturation capacity of the magnetite was determined for uranyl ions. The interaction between UO{sub 2}{sup 2+} ions and the magnetite was defined as a spontaneous chemical adsorption. (author)

  3. Grain-Size Based Additivity Models for Scaling Multi-rate Uranyl Surface Complexation in Subsurface Sediments

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Xiaoying; Liu, Chongxuan; Hu, Bill X.; Hu, Qinhong

    2016-07-01

    This study statistically analyzed a grain-size based additivity model that has been proposed to scale reaction rates and parameters from laboratory to field. The additivity model assumed that reaction properties in a sediment including surface area, reactive site concentration, reaction rate, and extent can be predicted from field-scale grain size distribution by linearly adding reaction properties for individual grain size fractions. This study focused on the statistical analysis of the additivity model with respect to reaction rate constants using multi-rate uranyl (U(VI)) surface complexation reactions in a contaminated sediment as an example. Experimental data of rate-limited U(VI) desorption in a stirred flow-cell reactor were used to estimate the statistical properties of multi-rate parameters for individual grain size fractions. The statistical properties of the rate constants for the individual grain size fractions were then used to analyze the statistical properties of the additivity model to predict rate-limited U(VI) desorption in the composite sediment, and to evaluate the relative importance of individual grain size fractions to the overall U(VI) desorption. The result indicated that the additivity model provided a good prediction of the U(VI) desorption in the composite sediment. However, the rate constants were not directly scalable using the additivity model, and U(VI) desorption in individual grain size fractions have to be simulated in order to apply the additivity model. An approximate additivity model for directly scaling rate constants was subsequently proposed and evaluated. The result found that the approximate model provided a good prediction of the experimental results within statistical uncertainty. This study also found that a gravel size fraction (2-8mm), which is often ignored in modeling U(VI) sorption and desorption, is statistically significant to the U(VI) desorption in the sediment.

  4. CsUV{sub 3}O{sub 11}, a new uranyl vanadate with a layered structure

    Energy Technology Data Exchange (ETDEWEB)

    Duribreux, I.; Dion, C.; Abraham, F. [Univ. des Sciences et Technologies de Lille, Villeneuve d`Ascq (France). Lab. de Cristallochimie et Physicochimie du Solide; Saadi, M. [Univ. Chouaib Doukkali, El Jadida (Morocco). Lab. de Chimie de Coordination et Analytique

    1999-08-01

    A new cesium uranyl vanadate CsUV{sub 3}O{sub 11} has been synthesized by solid state reaction. Its crystal structure has been determined from single-crystal X-ray diffraction data. It crystallizes in the monoclinic system with space group P2{sub 1}/a and unit cell parameters a = 11.904(2) {angstrom}, b = 6.8321(6) {angstrom}, c = 12.095(2) {angstrom}, {beta} = 106.989(5){degree}, Z = 4, and D{sub exp} = 4.89(2) g/cm{sup 3}. A full-matrix least squares refinement yielded R = 0.046 and R{sub w} = 0.045 for 1831 independent reflections with I > 3{sigma}(I) collected on a Nonius CAD4 diffractometer (MoK{alpha} radiation). The structure of CsUV{sub 3}O{sub 11} is characterized by [UV{sub 3}O{sub 11}]{sub {infinity}} layers parallel to the (001) plane. The layers, very similar to those found in UV{sub 3}O{sub 10}, are built up from VO{sub 5} square pyramids sharing corners of their equatorial bases and UO{sub 8} hexagonal bipyramids, the U atoms occupying the hexagonal holes created by the VO{sub 5} array. The Cs{sup +} ions are located between two successive layers and hold them together; the Cs{sup +} ions and two layers constitute a neutral sandwich {l_brace}(UV{sub 3}O{sub 11}{sup {minus}})-(Cs){sub 2}{sup 2+}-(UV{sub 3}O{sub 11}{sup {minus}}){r_brace}. In this unusual structure, the neutral sandwiches are stacked one above another along the [104] direction with no formal chemical bonds between the neutral sandwiches. The Cs mobilities in CsUV{sub 3}O{sub 11} and Cs carnotite are compared.

  5. Structural basis for Mep2 ammonium transceptor activation by phosphorylation.

    Science.gov (United States)

    van den Berg, Bert; Chembath, Anupama; Jefferies, Damien; Basle, Arnaud; Khalid, Syma; Rutherford, Julian C

    2016-04-18

    Mep2 proteins are fungal transceptors that play an important role as ammonium sensors in fungal development. Mep2 activity is tightly regulated by phosphorylation, but how this is achieved at the molecular level is not clear. Here we report X-ray crystal structures of the Mep2 orthologues from Saccharomyces cerevisiae and Candida albicans and show that under nitrogen-sufficient conditions the transporters are not phosphorylated and present in closed, inactive conformations. Relative to the open bacterial ammonium transporters, non-phosphorylated Mep2 exhibits shifts in cytoplasmic loops and the C-terminal region (CTR) to occlude the cytoplasmic exit of the channel and to interact with His2 of the twin-His motif. The phosphorylation site in the CTR is solvent accessible and located in a negatively charged pocket ∼30 Å away from the channel exit. The crystal structure of phosphorylation-mimicking Mep2 variants from C. albicans show large conformational changes in a conserved and functionally important region of the CTR. The results allow us to propose a model for regulation of eukaryotic ammonium transport by phosphorylation.

  6. Removal of chloridazon by natural and ammonium kerolite samples

    Science.gov (United States)

    Socías-Viciana, M. M.; Tévar de Fez, J.; Ureña-Amate, M. D.; González-Pradas, E.; Fernández-Pérez, M.; Flores-Céspedes, F.

    2006-06-01

    The adsorption of chloridazon (5-amino-4-chloro-2-phenylpyridazin-3(2H)-one) on natural and ammonium kerolite samples from aqueous solution at 10, 25 and 40 °C has been studied by using batch experiments. The experimental data points were fitted to the Langmuir equation in order to calculate the adsorption capacities ( Xm) of the samples; two straight lines were obtained, which indicates that the adsorption process takes place in two different stages. Values for Xm1 (first stage) ranged from 1.1 × 10 -2 mol kg -1 for natural kerolite at 40 °C up to 5.1 × 10 -2 mol kg -1 for ammonium kerolite at 10 °C and the values for Xm2 (second stage) ranged from 9.1 × 10 -2 mol kg -1 for natural kerolite at 40 °C up to 14 × 10 -2 mol kg -1 for natural kerolite at 10 °C. The adsorption experiments showed on the one hand, that the ammonium kerolite is more effective than natural kerolite to adsorb chloridazon in the range of temperature studied and on the other hand, that the lower temperature, the more effective the adsorption of chloridazon on the adsorbents studied.

  7. Extraction Factor Of Pure Ammonium Paratungstate From Tungsten Scraps

    Directory of Open Access Journals (Sweden)

    Pee J.-H.

    2015-06-01

    Full Text Available Typical oxidation process of tungsten scraps was modified by the rotary kiln with oxygen burner to increase the oxidation rate of tungsten scraps. Also to accelerate the solubility of solid oxidized products, the hydrothermal reflux method was adapted. By heating tungsten scraps in rotary kiln with oxygen burner at around 900° for 2hrs, the scraps was oxidized completely. Then oxidized products (WO3 and CoWO4 was fully dissolved in the solution of NaOH by hydrothermal reflux method at 150° for 2hrs. The dissolution rate of oxidized products was increased with increasing the reaction temperature and concentration of NaOH. And then CaWO4 and H2WO4 could be generated from the aqueous sodium tungstate solution. Ammonium paratungstate (APT also could be produced from tungstic acid using by aqueous ammonium solution. The morphologies (cubic and plate types of APT was controlled by the stirring process of purified solution of ammonium paratungstate.

  8. Ammonium nitrogen in fetuses of urea-treated sheep.

    Science.gov (United States)

    Yelverton, C C; Roller, M H; Swanson, R N

    1975-02-01

    Eight pregnant Southdown ewes were treated (by drench) with 12.5 ml of 3.3 M urea solution per kilogram of body weight, and ammonium nitrogen concentrations of blood and tissues of these ewes and their fetuses were measured and compared with those of control ewes (given water by drench) and their fetuses. Blood ammonium nitrogen (BAN) and tissue ammonium nitrogen (TAN) concentrations for liver, kidney, spleen, and muscle of ewes and fetuses were determined by an ion-exchange procedure. Samples of blood were collected before treatment, at 30, 90 and 150 minutes after treatment, and at death of the dam. The principal ewes had increasing BAN concentrations with time after drench, and their fetuses had significantly greater (P less than 0.01) BAN concentrations than fetuses from control ewes. All fetuses were alive after death of the dams and had lower TAN values than their dams. The differences in ammonia concentrations between ewes and fetuses were larger in the principal group than in the control group. Except for ewe muscle and fetal liver, all tissues of principals had significantly greater (P less than 0.01) TAN concentrations than those of controls. Muscle of principal ewes and hepatic tissues of their fetuses had greater (P less than 0.05) TAN concentrations than those of control ewes and their fetuses.

  9. Carbon and nitrogen cycling in intertidal sediments near Doel, Scheldt Estuary

    NARCIS (Netherlands)

    Middelburg, J.J.; Klaver, G.; Nieuwenhuize, J.; Vlug, T.

    1995-01-01

    Carbon and nitrogen cycling in intertidal mud flat sediments in the Scheldt Estuary was studied using measurements of carbon dioxide, methane and nitrous oxide emission rates and pore-water profiles of ΣCO2, ammonium and nitrate. A comparison between chamber measured carbon dioxide fluxes and those

  10. From greenhouse gas to feedstock: formation of ammonium carbamate from CO{sub 2} and NH{sub 3} in organic solvents and its catalytic conversion into urea under mild conditions

    Energy Technology Data Exchange (ETDEWEB)

    Barzagli, F.; Mani, F.; Peruzzini, M. [University of Florence, Florence (Italy). Dept. of Chemistry

    2011-07-01

    The capture of carbon dioxide by ammonia in both aqueous and non-aqueous solutions was investigated at atmospheric pressure and 273 K under different operating conditions. The CO{sub 2} capture is fast and efficient ranging between 78 and 99%, depending on both the NH{sub 3} concentration and the solvent nature. The precipitation of solid mixtures of ammonium bicarbonate, ammonium carbonate and ammonium carbamate occurred in ethanol-water solution. Selective precipitation of ammonium carbamate was achieved by reacting gaseous CO{sub 2} and NH{sub 3} in anhydrous ethanol, 1-propanol or N,N-dimethylformamide (DMF) in a flow reactor that operates in continuous. In the second step of the process, the pure ammonium carbamate is used to produce urea with good yield (up to 54% on carbamate basis) at 393-413 K in the presence of inexpensive Cu(II) and Zn(II) catalysts. The yield of urea depends on several factors including the catalyst, the reaction temperature and the reaction time. Identification and quantification of urea in the reaction mixtures was obtained by analysis of its {sup 13}C NMR spectrum. A preliminary mechanistic interpretation of the catalytic reaction is also briefly presented and commented.

  11. Characterization of the interaction of uranyl ions with humic acids by x-ray absorption spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Reich, T.; Denecke, M.A.; Pompe, S. [Inst. of Radiochemistry, Dresden (Germany)] [and others

    1995-11-01

    Humic substances are present throughout the environment in soil and natural water. They are organic macromolecules with a variable structural formula, molecular weight, and a wide variety of functional groups depending on their origin. In natural waters, humic substances represent the main component of the {open_quotes}dissolved organic carbon{close_quotes} (DOC). The DOC may vary considerably from 1 mg/L at sea water surfaces to 50 mg/L at the surface in dark water swamps. There is strong evidence that all actinides form complexes with humic substances in natural waters. Therefore, humic substances can play an important role in the environmental migration of radionuclides by enhancing their transport. Retardation through humic substance interaction may be also possible due to formation of precipitating agglomerates. For remediation and restoration of contaminated environmental sites and risk assessment of future nuclear waste repositories, it is important to improve the predictive capabilities for radionuclide migration through a better understanding of the interaction of radionuclides with humic substances.

  12. Quaternary ammonium salt N-(dodecyloxycarboxymethyl)-N,N,N-trimethyl ammonium chloride induced alterations in Saccharomyces cerevisiae physiology

    Indian Academy of Sciences (India)

    EWA OBŁĄK; AGATA PIECUCH; EWA MACIASZCZYK-DZIUBIŃSKA; DONATA WAWRZYCKA

    2016-12-01

    We investigated the influence of the quaternary ammonium salt (QAS) called IM (N-(dodecyloxycarboxymethyl)-N,N,N-trimethyl ammonium chloride) on yeast cells of the parental strain and the IM-resistant mutant (EO25 IMR)growth. The phenotype of this mutant was pleiotropic. The IMR mutant exhibited resistance to ethanol, osmotic shockand oxidative stress, as well as increased sensitivity to UV. Moreover, it was noted that mutant EO25 appears to havean increased resistance to clotrimazole, ketoconazole, fluconazole, nystatin and cycloheximide. It also toleratedgrowth in the presence of crystal violet, DTT and metals (selenium, tin, arsenic). It was shown that the presence ofIM decreased ergosterol level in mutant plasma membrane and increased its unsaturation. These results indicatechanges in the cell lipid composition. Western blot analysis showed the induction of Pma1 level by IM. RT-PCRrevealed an increased PMA1 expression after IM treatment.

  13. Evidence for surface nucleation: efflorescence of ammonium sulfate and coated ammonium sulfate aerosol particles

    Science.gov (United States)

    Ciobanu, V. Gabriela; Marcolli, Claudia; Krieger, Ulrich K.; Zuend, Andreas; Peter, Thomas

    2010-05-01

    Aerosol particles are ubiquitous in the atmosphere and can undergo different phase transitions, such as deliquescence and efflorescence. Using optical microscopy, we investigated the efflorescence of ammonium sulfate (AS) in supersaturated AS and 1:1 and 8:1 (by weight) poly(ethylene glycol)-400 (PEG-400)/AS particles, which were deposited as droplets with diameters in the 16 - 35 μm range on a hydrophobically coated slide. The PEG-400/AS particles that are exposed to decreasing relative humidity (RH) exhibit a liquid-liquid phase separation below 90 % RH with the PEG-400 phase surrounding the aqueous AS inner phase (Marcolli and Krieger, 2006; Ciobanu et al., 2009). Pure AS particles effloresced in the RH range from 36.3 to 43.7 % RH, in agreement with literature data (31 - 48 % RH). In contrast, 1:1 PEG-400/AS particles with diameters of the AS phase from 7.2 - 19.2 μm effloresced between 26.8 - 33.9 % RH and 8:1 PEG-400/AS particles with diameters of the AS phase from 1.8 - 7.3 μm between 24.3 - 29.3 % RH. Such low efflorescence relative humidity (ERH) values have never been reached before for AS particles of this size range. We show that neither a potential inhibition of water evaporation via anomalously slow diffusion through the PEG coating, nor the presence of low amounts of PEG-400 in the AS phase, nor different timescales between various experimental techniques could possibly explain the low AS ERH values of PEG-400/AS particles in our setup. High-speed photography of the efflorescence process allowed to monitor the proceeding of the AS crystallization fronts within the particles with millisecond time resolution. The nucleation locations were deduced based on the initial crystals growth locations. Statistical analysis of 31 and 19 efflorescence events for pure AS and 1:1 PEG-400/AS particles, respectively, identified the air/droplet/substrate contact line and the air/droplet interface as preferred nucleation locations in the case of pure AS particles

  14. Development of Electroactive and Anaerobic Ammonium-Oxidizing (Anammox Biofilms from Digestate in Microbial Fuel Cells

    Directory of Open Access Journals (Sweden)

    Enea Gino Di Domenico

    2015-01-01

    Full Text Available Microbial Fuel cells (MFCs have been proposed for nutrient removal and energy recovery from different wastes. In this study the anaerobic digestate was used to feed H-type MFC reactors, one with a graphite anode preconditioned with Geobacter sulfurreducens and the other with an unconditioned graphite anode. The data demonstrate that the digestate acts as a carbon source, and even in the absence of anode preconditioning, electroactive bacteria colonise the anodic chamber, producing a maximum power density of 172.2 mW/m2. The carbon content was also reduced by up to 60%, while anaerobic ammonium oxidation (anammox bacteria, which were found in the anodic compartment of the reactors, contributed to nitrogen removal from the digestate. Overall, these results demonstrate that MFCs can be used to recover anammox bacteria from natural sources, and it may represent a promising bioremediation unit in anaerobic digestor plants for the simultaneous nitrogen removal and electricity generation using digestate as substrate.

  15. Partial nitrification of non-ammonium-rich wastewater within biofilm filters under ambient temperature.

    Science.gov (United States)

    Wang, Hongyu; He, Jiajie; Yang, Kai

    2010-01-01

    This study evaluated the partial nitrification performances of two biofilm filters over a synthetic non-ammonium-rich wastewater at a 20°C room temperature under both limited DO (∼2.0 mg/L) and unlimited DO (∼4.0 mg/L) conditions. The two filters were each of 80 cm long and used different biofilm carriers: activated carbon and ceramic granule. Results showed that partial nitrification was accomplished for both filters under the limited DO condition. However, the effluent NO(2)-N was higher in the ceramic granule filter than in the activated carbon filter, and was less susceptible to the influent COD/N changes. Further investigation into the water phase COD and NH(4)-N depth profiles and bacteria population within the two filters showed that by putting upper filter layer (upstream) to confront relatively higher influent COD/N ratios, the filtration process naturally put lower filter layers (downstream) relatively more favorable for nitrifying bacteria (ammonia oxidizing bacteria in this study) to prosper, making the filter depth left for nitrification a crucial factor for the effectiveness of nitrification with a filter. The potentially different porous flow velocities of the two filters might be the reason to cause their different partial nitrification performances, with a lower porous flow velocity (the ceramic granule filter) favoring partial nitrification more. In summation, DO, filter depth, and filtration speed should be played together to successfully operate a biofilm filter for partial nitrification.

  16. PLA with Intumescent System Containing Lignin and Ammonium Polyphosphate for Flame Retardant Textile

    Directory of Open Access Journals (Sweden)

    Aurélie Cayla

    2016-09-01

    Full Text Available Using bio-based polymers to replace of polymers from petrochemicals in the manufacture of textile fibers is a possible way to improve sustainable development for the textile industry. Polylactic acid (PLA is one of the available bio-based polymers. One way to improve the fire behavior of this bio-based polymer is to add an intumescent formulation mainly composed of acid and carbon sources. In order to optimize the amount of bio-based product in the final material composition, lignin from wood waste was selected as the carbon source. Different formulations of and/or ammonium polyphosphate (AP were prepared by melt extrusion and then hot-pressed into sheets. The thermal properties (thermogravimetric analyses (TGA and differential scanning calorimetry (DSC and fire properties (UL-94 were measured. The spinnability of the various composites was evaluated. The mechanical properties and physical aspect (microscopy of PLA multifilaments with lignin (LK were checked. A PLA multifilament with up to 10 wt % of intumescent formulation was processed, and the fire behavior of PLA fabrics with lignin/AP formulation was studied by cone calorimeter.

  17. A literature review of actinide-carbonate mineral interactions

    Energy Technology Data Exchange (ETDEWEB)

    Stout, D.L. [Missouri Univ., Columbia, MO (United States). Dept. of Geological Sciences; Carroll, S.A. [Lawrence Livermore National Lab., CA (United States)

    1993-10-01

    Chemical retardation of actinides in groundwater systems is a potentially important mechanism for assessing the performance of the Waste Isolation Pilot Plant (WIPP), a facility intended to demonstrate safe disposal of transuranic waste. Rigorous estimation of chemical retardation during transport through the Culebra Dolomite, a water-bearing unit overlying the WIPP, requires a mechanistic understanding of chemical reactions between dissolved elements and mineral surfaces. This report represents a first step toward this goal by examining the literature for pertinent experimental studies of actinide-carbonate interactions. A summary of existing models is given, along with the types of experiments on which these models are based. Articles pertaining to research into actinide interactions with carbonate minerals are summarized. Select articles involving trace element-carbonate mineral interactions are also reviewed and may serve as templates for future research. A bibliography of related articles is included. Americium(III), and its nonradioactive analog neodymium(III), partition strongly from aqueous solutions into carbonate minerals. Recent thermodynamic, kinetic, and surface studies show that Nd is preferentially removed from solution, forming a Nd-Ca carbonate solid solution. Neptunium(V) is rapidly removed from solution by carbonates. Plutonium incorporation into carbonates is complicated by multiple oxidation states. Little research has been done on the radium(H) and thorium(IV) carbonate systems. Removal of uranyl ion from solution by calcite is limited to monolayer surface coverage.

  18. Insight into Hydrogen Bonding of Uranyl Hydroxide Layers and Capsules by Use of 1H Magic-Angle Spinning NMR Spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Alam, Todd M. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States). Dept. of Organic Material Science; Liao, Zuolei [Oregon State Univ., Corvallis, OR (United States). Dept. of Chemistry and Materials; Nyman, May [Oregon State Univ., Corvallis, OR (United States). Dept. of Chemistry and Materials; Yates, Jonathan [Univ. of Oxford (United Kingdom). Dept. of Materials

    2016-04-27

    In this paper, solid-state 1H magic-angle spinning (MAS) NMR was used to investigate local proton environments in anhydrous [UO2(OH)2] (α-UOH) and hydrated uranyl hydroxide [(UO2)4O(OH)6·5H2O (metaschoepite). For the metaschoepite material, proton resonances of the μ2-OH hydroxyl and interlayer waters were resolved, with two-dimensional (2D) double-quantum (DQ) 1H–1H NMR correlation experiments revealing strong dipolar interactions between these different proton species. The experimental NMR results were combined with first-principles CASTEP GIPAW (gauge including projector-augmented wave) chemical shift calculations to develop correlations between hydrogen-bond strength and observed 1H NMR chemical shifts. Finally, these NMR correlations allowed characterization of local hydrogen-bond environments in uranyl U24 capsules and of changes in hydrogen bonding that occurred during thermal dehydration of metaschoepite.

  19. Multifunctional uranyl hybrid materials: structural diversities as a function of pH, luminescence with potential nitrobenzene sensing, and photoelectric behavior as p-type semiconductors.

    Science.gov (United States)

    Song, Jian; Gao, Xue; Wang, Zhi-Nan; Li, Cheng-Ren; Xu, Qi; Bai, Feng-Ying; Shi, Zhong-Feng; Xing, Yong-Heng

    2015-09-21

    A series of uranyl-organic frameworks (UOFs), {[(UO2)2(H2TTHA)(H2O)]·4,4'-bipy·2H2O}n (1), {[(UO2)3(TTHA)(H2O)3]}n (2), and {[(UO2)5(TTHA) (HTTHA)(H2O)3]·H3O}n (3), have been obtained by the hydrothermal reaction of uranyl acetate with a flexible hexapodal ligand (1,3,5-triazine-2,4,6-triamine hexaacetic acid, H6TTHA). These compounds exhibited three distinct 3D self-assembly architectures as a function of pH by single-crystal structural analysis, although the used ligand was the same in each reaction. Surprisingly, all of the coordination modes of the H6TTHA ligand in this work are first discovered. Furthermore, the photoluminescent results showed that these compounds displayed high-sensitivity luminescent sensing functions for nitrobenzene. Additionally, the surface photovoltage spectroscopy and electric-field-induced surface photovoltage spectroscopy showed that compounds 1-3 could behave as p-type semiconductors.

  20. Additional studies on mixed uranyl oxide-hydroxide hydrate alteration products of uraninite from the palermo and ruggles granitic pegmatites, grafton county, New Hampshire

    Science.gov (United States)

    Foord, E.E.; Korzeb, S.L.; Lichte, F.E.; Fitzpatrick, J.J.

    1997-01-01

    Additional studies on an incompletely characterized secondary uranium "mineral" from the Ruggles and Palermo granitic pegmatites, New Hampshire, referred to as mineral "A" by Frondel (1956), reveal a mixture of schoepite-group minerals and related uranyl oxide-hydroxide hydrated compounds. A composite chemical analysis yielded (in wt.%): PbO 4.85 (EMP), UO3 83.5 (EMP), BaO 0.675 (av. of EMP and ICP), CaO 0.167 (av. of EMP and ICP), K2O 2.455 (av. of EMP and ICP), SrO 0.21 (ICP), ThO2 0.85 (ICP), H2O 6.9, ??99.61. Powder-diffraction X-ray studies indicate a close resemblance in patterns between mineral "A" and several uranyl oxide-hydroxide hydrated minerals, including the schoepite family of minerals and UO2(OH)2. The powder-diffraction data for mineral "A" are most similar to those for synthetic UO2.86??1.5H2O and UO2(OH)2, but other phases are likely present as well. TGA analysis of both mineral "A" and metaschoepite show similar weight-loss and first derivative curves. The dominant losses are at 100??C, with secondary events at 400?? and 600??C. IR spectra show the presence of (OH) and H2O. Uraninite from both pegmatites, analyzed by LAM-ICP-MS, shows the presence of Th, Pb, K and Ca.

  1. [La(UO2)V2O7][(UO2)(VO4)] the first lanthanum uranyl-vanadate with structure built from two types of sheets based upon the uranophane anion-topology

    Science.gov (United States)

    Mer, A.; Obbade, S.; Rivenet, M.; Renard, C.; Abraham, F.

    2012-01-01

    The new lanthanum uranyl vanadate divanadate, [La(UO2)V2O7][(UO2)(VO4)] was obtained by reaction at 800 °C between lanthanum chloride, uranium oxide (U3O8) and vanadium oxide (V2O5) and the structure was determined from single-crystal X-ray diffraction data. This compound crystallizes in the orthorhombic system with space group P212121 and unit-cell parameters a=6.9470(2) Å, b=7.0934(2) Å, c=25.7464(6) Å, V=1268.73(5) Å3, Z=4. A full matrix least-squares refinement yielded R1=0.0219 for 5493 independent reflections. The crystal structure is characterized by the stacking of uranophane-type sheets [(UO2)(VO4)]-∞2 and double layers [La(UO2)(V2O7)]+∞2 connected through La-O bonds involving the uranyl oxygen of the uranyl-vanadate sheets. The double layers result from the connection of two [La(UO2)(VO4)2]-∞2 sheets derived from the uranophane anion-topology by replacing half of the uranyl ions by lanthanum atoms and connected through the formation of divanadate entities.

  2. Influence of heterogeneous ammonium availability on bacterial community structure and the expression of nitrogen fixation and ammonium transporter genes during in situ bioremediation of uranium-contaminated groundwater

    Energy Technology Data Exchange (ETDEWEB)

    Mouser, P.J.; N' Guessan, A.L.; Elifantz, H.; Holmes, D.E.; Williams, K.H.; Wilkins, M.J.; Long, P.E.; Lovley, D.R.

    2009-04-01

    The impact of ammonium availability on microbial community structure and the physiological status and activity of Geobacter species during in situ bioremediation of uranium-contaminated groundwater was evaluated. Ammonium concentrations varied by as much as two orders of magnitude (<4 to 400 {micro}M) across the study site. Analysis of 16S rRNA gene sequences suggested that ammonium influenced the composition of the microbial community prior to acetate addition with Rhodoferax species predominating over Geobacter species at the site with the highest ammonium, and Dechloromonas species dominating at sites with lowest ammonium. However, once acetate was added, and dissimilatory metal reduction was stimulated, Geobacter species became the predominant organisms at all locations. Rates of U(VI) reduction appeared to be more related to the concentration of acetate that was delivered to each location rather than the amount of ammonium available in the groundwater. In situ mRNA transcript abundance of the nitrogen fixation gene, nifD, and the ammonium importer gene, amtB, in Geobacter species indicated that ammonium was the primary source of nitrogen during in situ uranium reduction, and that the abundance of amtB transcripts was inversely correlated to ammonium levels across all sites examined. These results suggest that nifD and amtB expression by subsurface Geobacter species are closely regulated in response to ammonium availability to ensure an adequate supply of nitrogen while conserving cell resources. Thus, quantifying nifD and amtB expression appears to be a useful approach for monitoring the nitrogen-related physiological status of Geobacter species in subsurface environments during bioremediation. This study also emphasizes the need for more detailed analysis of geochemical/physiological interactions at the field scale, in order to adequately model subsurface microbial processes.

  3. CRYSTALLIZATION KINETICS OF AMMONIUM PERCHLORATE IN AN AGITATED VESSEL

    Directory of Open Access Journals (Sweden)

    Nahidh Kaseer

    2013-05-01

    Full Text Available 31Overall crystal growth kinetics for ammonium perchlorate in laboratory scale batch  agitated vessel crystallizer have been determined from batch experiments performed in an integral mode. The effects of temperature between 30-60ºC, seed size 0.07, 0.120 and 0.275 mm and stirrer speed 160, 340, and 480 rpm, on the kinetics of crystal growth were investigated. Two different methods, viz. polynomial fitting and initial derivative were used to predict the kinetics expression. In general both methods gave comparable results for growth kinetics estimation. The order of growth process is not more than two. The activation energy for crystal growth of ammonium perchlorate was determined and found  to be equal to 5.8 kJ/ mole.            Finally, the influence of the affecting parameters on the crystal growth rate gives general expression that had an obvious dependence of the growth rate on each variables of concern (temperature, seed size, and stirrer speed .The general overall growth rate expression had shown that super saturation is the most significant variable. While the positive dependence of the stirrer speed demonstrates the importance of the diffusional step in the growth rate model. Moreover, the positive dependence of the seed size demonstrate the importance of the surface integration  step in the growth rate model. All the studied variables tend to suggest that the growth rate characteristics  of ammonium perchlorate from aqueous solution commenced in a batch crystallizer are diffusion kinetic controlled process.

  4. The Properties of Ammonium Dinitramine (ADN): Part 2: Melt Casting

    Science.gov (United States)

    Hahma, A.; Edvinsson, H.; Östmark, H.

    2010-04-01

    A melt casting technique for ammonium dinitramine (ADN) and ADN/aluminum was developed. ADN proved relatively easy to cast, when 1% of magnesium oxide was used as a stabilizer and crystallization kernels. Densities of ADN/MgO 99/1 were 92 to 97% of theoretical mean density (TMD) and those of ADN/Al/MgO 64/35/1 were between 95 and 99% of TMD. Sedimentation of Al in the melt was prevented and the particle wetting was ensured by selecting a suitable particle size for Al. No gelling agents or other additives were used. The casting process and factors influencing it are discussed.

  5. Surge ammonium uptake in macroalgae from a coral atoll

    Digital Repository Service at National Institute of Oceanography (India)

    Raikar, V.; Wafar, M.V.M.

    Maintenance of high levels of biological productivity (up to several gC m-2 d-1) (Crossland et al., 1991) by coral atolls in oligotrophic oceanic waters with low ambient concentrations of N nutrients (typically of the order of few hundreds of nmols..., fish shoals migrating onto the reef could raise ambient ammonium concentrations in the vicinity of corals up to 0.9 ? M (Meyer et al., 1983) and area-specific N regeneration by actively feeding holothurians (Uthicke and Klumpp, 1998) could be in a...

  6. Further laboratory and theoretical investigations of ammonium dinitramide

    Energy Technology Data Exchange (ETDEWEB)

    Tulis, A.J.; Snelson, A. [IIT Research Institut, Chicago (United States); Heberlein, C.; Patel, D.L. [U.S. Army Cecom RD et E Center, NVESD (United States)

    1996-12-31

    Hydrogen and deuterated ammonium dinitramide have been vaporized under high vacuum and the IR matrix isolation spectra of the decomposition products obtained. Tentative vibration assignments have been made for HN(NO{sub 2}){sub 2} and DN(NO{sub 2}){sub 2} assuming a symmetrical non-planar structure in which the H or D is bonded to the central nitrogen atom. Other structures are also possible. Ab initio calculations have been made for the various structural isomers of hydrogen dinitramide. Vibration frequencies calculated for the hydrogenated and deuterated species are compared with the experimental values with the object of identifying the molecules` structure. (authors) 3 refs.

  7. Experimental study of the detonation of technical grade ammonium nitrate

    Science.gov (United States)

    Presles, Henri-Noël; Vidal, Pierre; Khasainov, Boris

    2009-11-01

    The detonation of technical grade ammonium nitrate at the density ρ=0.666 g/cm confined in PVC and steel tubes was experimentally studied. The results show that the detonation is self-sustained and steady in steel tubes with diameter as small as 12 mm. Critical detonation diameter lies between 8 and 12 mm in 2 mm thick steel tubes and between 55 and 81 mm in PVC tubes. These values testify a strong detonation sensitivity of this product. To cite this article: H.-N. Presles et al., C. R. Mecanique 337 (2009).

  8. Ammonium diamminesilver(I bis(5-chloro-2-hydroxybenzenesulfonate trihydrate

    Directory of Open Access Journals (Sweden)

    Zhao-Peng Deng

    2012-02-01

    Full Text Available The reaction of silver nitrate with 5-chloro-2-hydroxybenzenesulfonic acid in the presence of ammonia yielded the title salt, (NH4[Ag(NH32](C6H4ClO4S2·3H2O. The AgI ion shows linear coordination [N—Ag—N = 175.2 (1 °]. The ammonium and diamminesilver cations, the benzenesulfonate anion and the lattice water molecules interact through an intricate network of N—H...O and O—H...O hydrogen bonds to form a three-dimensional network.

  9. Structure of butanol and hexanol at aqueous, ammonium bisulfate, and sulfuric acid solution surfaces investigated by vibrational sum frequency generation spectroscopy.

    Science.gov (United States)

    Van Loon, Lisa L; Minor, Rena N; Allen, Heather C

    2007-08-09

    The organization of 1-butanol and 1-hexanol at the air-liquid interface of aqueous, aqueous ammonium bisulfate, and sulfuric acid solutions was investigated using vibrational broad bandwidth sum frequency generation spectroscopy. There is spectroscopic evidence supporting the formation of centrosymmetric structures at the surface of pure butanol and pure hexanol. At aqueous, ammonium bisulfate, and at most sulfuric acid solution surfaces, butanol molecules organize in all-trans conformations. This suggests that butanol self-aggregates. The spectrum for the 0.052 M butanol in 59.5 wt % sulfuric acid solution is different from the other butanol solution spectra, that is, the surface butanol molecules are observed to possess a significant number of gauche defects. Relative to surface butanol, surface hexanol chains are more disordered at the surface of their respective solutions. Statistically, an increase in the number of gauche defects is expected for hexanol relative to butanol, a six carbon chain vs a four carbon chain. Yet, self-aggregation of hexanol at its aqueous solution surfaces is not ruled out because the methylene spectral contribution is relatively small. The surface spectra for butanol and hexanol also show evidence for salting out from the ammonium bisulfate solutions.

  10. Infrared Multiphoton Dissociation Spectroscopy of a Gas-Phase Complex of Uranyl and 3-Oxa-Glutaramide: An Extreme Red-Shift of the [O=U=O]²⁺ Asymmetric Stretch

    Energy Technology Data Exchange (ETDEWEB)

    Gibson, John K.; Hu, Hanshi; Van Stipdonk, Michael J.; Berden, Giel; Oomens, Jos; Li, Jun

    2015-04-09

    The gas-phase complex UO₂(TMOGA)₂²⁺ (TMOGA = tetramethyl-3-oxa-glutaramide) prepared by electrospray ionization was characterized by infrared multiphoton dissociation (IRMPD) spectroscopy. The IRMPD spectrum from 700–1800 cm⁻¹ was interpreted using a computational study based on density functional theory. The predicted vibrational frequencies are in good agreement with the measured values, with an average deviation of only 8 cm⁻¹ (<1%) and a maximum deviation of 21 cm⁻¹ (<2%). The only IR peak assigned to the linear uranyl moiety was the asymmetric ν₃ mode, which appeared at 965 cm⁻¹ and was predicted by DFT as 953 cm⁻¹. This ν₃ frequency is red-shifted relative to bare uranyl, UO₂²⁺, by ca. 150 cm⁻¹ due to electron donation from the TMOGA ligands. Based on the degree of red-shifting, it is inferred that two TMOGA oxygen-donor ligands have a greater effective gas basicity than the four monodentate acetone ligands in UO₂(acetone)₄²⁺. The uranyl ν₃ frequency was also computed for uranyl coordinated by two TMGA ligands, in which the central Oether of TMOGA has been replaced by CH₂. The computed ν₃ for UO₂(TMGA)₂²⁺, 950 cm⁻¹, is essentially the same as that for UO₂(TMOGA)₂²⁺, suggesting that electron donation to uranyl from the Oether of TMOGA is minor. The computed ν₃ asymmetric stretching frequencies for the three actinyl complexes, UO₂(TMOGA)₂²⁺, NpO₂(TMOGA)₂²⁺ and PuO₂(TMOGA)₂²⁺, are comparable. This similarity is discussed in the context of the relationship between ν₃ and intrinsic actinide-oxygen bond energies in actinyl complexes.

  11. Overexpression of a soybean gene encoding cytosolic glutamine synthetase in shoots of transgenic Lotus corniculatus L. plants triggers changes in ammonium assimilation and plant development.

    Science.gov (United States)

    Vincent, R; Fraisier, V; Chaillou, S; Limami, M A; Deleens, E; Phillipson, B; Douat, C; Boutin, J P; Hirel, B

    1997-01-01

    A soybean cytosolic glutamine synthetase gene (GS15) was fused with the constitutive 35S cauliflower mosaic virus (CaMV) promoter in order to direct overexpression in Lotus corniculatus L. plants. Following transformation with Agrobacterium rhizogenes, eight independent Lotus transformants were obtained which synthesized additional cytosolic glutamine synthetase (GS) in the shoots. To eliminate any interference caused by the T-DNA from the Ri plasmid, three primary transformants were crossed with untransformed plants and progeny devoid of TL- and TR-DNA sequences were chosen for further analyses. These plants had a 50-80% increase in total leaf GS activity. Plants were grown under different nitrogen regimes (4 or 12 mM NH4+) and aspects of carbon and nitrogen metabolism were examined. In roots, an increase in free amino acids and ammonium was accompanied by a decrease in soluble carbohydrates in the transgenic plants cultivated with 12 mM NH4+ in comparison to the wild type grown under the same conditions. Labelling experiments using 15NH4+ were carried out in order to monitor the influx of ammonium and its subsequent incorporation into amino acids. This experiment showed that both ammonium uptake in the roots and the subsequent translocation of amino acids to the shoots was lower in plants overexpressing GS. It was concluded that the build up of ammonium and the increase in amino acid concentration in the roots was the result of shoot protein degradation. Moreover, following three weeks of hydroponic culture early floral development was observed in the transformed plants. As all these properties are characteristic of senescent plants, these findings suggest that expression of cytosolic GS in the shoots may accelerate plant development, leading to early senescence and premature flowering when plants are grown on an ammonium-rich medium.

  12. Biological removal of selenate and ammonium by activated sludge in a sequencing batch reactor.

    Science.gov (United States)

    Mal, J; Nancharaiah, Y V; van Hullebusch, E D; Lens, P N L

    2017-04-01

    Wastewaters contaminated by both selenium and ammonium need to be treated prior to discharge into natural water bodies, but there are no studies on the simultaneous removal of selenium and ammonium. A sequencing batch reactor (SBR) was inoculated with activated sludge and operated for 90days. The highest ammonium removal efficiency achieved was 98%, while the total nitrogen removal was 75%. Nearly a complete chemical oxygen demand removal efficiency was attained after 16days of operation, whereas complete selenate removal was achieved only after 66days. The highest total Se removal efficiency was 97%. Batch experiments showed that the total Se in the aqueous phase decreased by 21% with increasing initial ammonium concentration from 50 to 100mgL(-1). This study showed that SBR can remove both selenate and ammonium via, respectively, bioreduction and partial nitrification-denitrification and thus offer possibilities for treating selenium and ammonium contaminated effluents.

  13. Relations of ammonium minerals at several hydrothermal systems in the western U.S.

    Science.gov (United States)

    Krohn, M. Dennis; Kendall, Carol; Evans, John R.; Fries, Terry L.

    1993-08-01

    Ammonium bound to silicate and sulfate minerals has recently been located at several major hydrothermal systems in the western U.S. utilizing newly-discovered near-infrared spectral properties. Knowledge of the origin and mineralogic relations of ammonium minerals at known hydrothermal systems is critical for the proper interpretation of remote sensing data and for testing of possible links to mineralization. Submicroscopic analysis of ammonium minerals from two mercury- and gold-bearing hot-springs deposits at Ivanhoe, Nevada and McLaughlin, California shows that the ammonium feldspar, buddingtonite, occurs as fine-grained euhedral crystals coating larger sulfide and quartz crystals. Ammonium feldspar seems to precipitate relatively late in the crystallization sequence and shows evidence for replacement of NH 4 + by K + or other monovalent cations. Some buddingtonite is observed in close association with mercury, but not with gold. Ammonioalunite is found in a variety of isolated crystal forms at both deposits. Nitrogen isotopic values for ammonium-bearing minerals show a 14‰ range in composition, precluding assignment of a specific provenance to the nitrogen. The correlations of nitrogen isotopic values with depth and ammonium content suggest some loss of nitrogen in the oxidizing supergene environment, possibly as a metastable mineral. The high ammonium content in these hydrothermal systems, the close association to mercury, and the small crystal size of the ammonium-bearing minerals all suggest that ammonium may be transported in a late-stage vapor phase or as an organic volatile. Such a process could lead to the formation of a non-carbonaceous organic aureole above a buried geothermal source. The discovery of a 10-km outcrop of ammonium minerals confirms that significant substitution of ammonium in minerals is possible over an extensive area and that remote sensing is a feasible means to detect such aureoles.

  14. Effects of Calcium Lignosulfonate and Silicic Acid on Ammonium Nitrate Degradation

    Directory of Open Access Journals (Sweden)

    Ahmet Ozan Gezerman

    2014-01-01

    Full Text Available Ammonium nitrate salts are the most commonly used nitrogenous fertilizers in industry. However, storage of ammonium nitrate is problematic, since its initial properties can decline because of environmental factors, leading to large economic losses. In this study, in order to prevent the caking and degradation of ammonium nitrate, an alternative composition with additional calcium lignosulfonate and silicic acid was studied. The resulting fertilizer was analyzed by screening analysis, ion chromatography, and electron microscopy methods.

  15. Shock Initiation and Equation of State of Ammonium Nitrate

    Science.gov (United States)

    Robbins, David; Sheffield, Steve; Dattelbaum, Dana; Chellappa, Raja; Velisavljevic, Nenad

    2013-06-01

    Ammonium nitrate (AN) is a widely used fertilizer and mining explosive commonly found in ammonium nitrate-fuel oil. Neat AN is a non-ideal explosive with measured detonation velocities approaching 4 km/s. Previously, we reported a thermodynamically-complete equation of state for AN based on its maximum density, and showed that near-full density AN did not initiate when subjected to shock input conditions up to 22 GPa. In this work, we extend these initial results, by presenting new Hugoniot data for intermediate density neat AN obtained from gas gun-driven plate impact experiments. AN at densities from 1.8 to 1.5 g/cm3 were impacted into LiF windows using a two-stage light gas gun. Dual VISARs were used to measure the interfacial particle velocity wave profile as a function of time following impact. The new Hugoniot data, in addition to updates to thermodynamic parameters derived from structural analysis and vibrational spectroscopy measurements in high pressure diamond anvil cell experiments, are used to refine the unreacted EOS for AN. Furthermore, shock initiation of neat AN was observed as the initial porosity increased (density decreased). Insights into the relationship(s) between initial density and shock initiation sensitivity are also presented, from evidence of shock initiation in the particle velocity profiles obtained for the lower density AN samples.

  16. Removal of vanadium from ammonium molybdate solution by ion exchange

    Institute of Scientific and Technical Information of China (English)

    LI Qing-gang; ZHANG Qi-xiu; ZENG Li; XIAO Lian-sheng; YANG Ya-nan

    2009-01-01

    The separation techniques of vanadium and molybdenum were summarized, and a new method of removal V(Ⅴ) from Mo(Ⅵ) by adsorption with chelate resin was presented. Nine kinds of chelate resins were used to investigate the adsorbent capability of V(Ⅴ) in ammonium molybdate solution with static method. The test results show that DDAS, CUW and CW-2 resins can easily adsorb V(Ⅴ) in ammonium molybdate solution, but hardly adsorb Mo(Ⅵ). The dynamic experimental results show more than 99.5% of V(Ⅴ) can be adsorbed, and the adsorption rate of Mo(Ⅵ) is less than 0.27% at 294-296 K for 60 min at pH 7.42-8.02. The mass ratio of V to Mo decreases to l/5 0000 in the effluent from 1/255 in the initial solution. The loaded resin can be desorbed by 5% NH3·H2O solution, and the vanadium desorption rate can reach 99.6%. The max concentration of vanadium in desorbed solution can reach 20 g/L, while the concentration of molybdenum is less than 0.8 g/L.

  17. Regulation by ammonium of glutamate dehydrogenase (NADP+) from Saccharomyces cerevisiae.

    Science.gov (United States)

    Bogonez, E; Satrústegui, J; Machado, A

    1985-06-01

    The activity of glutamate dehydrogenase (NADP+) (EC 1.4.1.4; NADP-GDH) of Saccharomyces cerevisiae is decreased under conditions in which intracellular ammonia concentrations increases. A high internal ammonia concentration can be obtained (a) by increasing the ammonium sulphate concentration in the culture medium, and (b) by growing the yeast either in acetate + ammonia media, where the pH of the medium rises during growth, or in heavily buffered glucose + ammonia media at pH 7.5. Under these conditions cellular oxoglutarate concentrations do not vary and changes in NADP-GDH activity appear to provide a constant rate of oxoglutarate utilization. The following results suggest that the decrease in NADP-GDH activity in ammonia-accumulating yeast cells is brought about by repression of synthesis: (i) after a shift to high ammonium sulphate concentrations, the number of units of activity per cell decreased as the inverse of cell doubling; and (ii) the rate of degradation of labelled NADP-GDH was essentially the same in ammonia-accumulating yeast cells and in controls, whereas the synthesis constant was much lower in the ammonia-accumulating cells than in the controls.

  18. Fabrication and cytocompatibility of spherical magnesium ammonium phosphate granules.

    Science.gov (United States)

    Christel, Theresa; Geffers, Martha; Klammert, Uwe; Nies, Berthold; Höß, Andreas; Groll, Jürgen; Kübler, Alexander C; Gbureck, Uwe

    2014-09-01

    Magnesium phosphate compounds, as for example struvite (MgNH4PO4·6H2O), have comparable characteristics to calcium phosphate bone substitutes, but degrade faster under physiological conditions. In the present work, we used a struvite forming calcium doped magnesium phosphate cement with the formulation Ca0.75Mg2.25(PO4)2 and an ammonium phosphate containing aqueous solution to produce round-shaped granules. For the fabrication of spherical granules, the cement paste was dispersed in a lipophilic liquid and stabilized by surfactants. The granules were characterized with respect to morphology, size distribution, phase composition, compressive strength, biocompatibility and solubility. In general, it was seen that small granules can hardly be produced by means of emulsification, when the raw material is a hydraulic paste, because long setting times promote coalescence of initially small unhardened cement droplets. Here, this problem was solved by using an aqueous solution containing both the secondary (NH4)2HPO4 and primary ammonium phosphates NH4H2PO4 to accelerate the setting reaction. This resulted in granules with 97 wt.% having a size in the range between 200 and 1,000 μm. The novel solution composition doubled the compressive strength of the cement to 37 ± 5 MPa without affecting either the conversion to struvite or the cytocompatibility using human fetal osteoblasts.

  19. Development of electrochemical denitrification from waste water containing ammonium nitrate

    Energy Technology Data Exchange (ETDEWEB)

    Sawa, Toshio; Hirose, Yasuo; Ishii, Yoshinori; Takatsudo, Atsushi; Wakasugi, Kazuhico; Hayashi, Hiroshi

    1995-12-31

    The authors developed processes to dentrify waste water containing ammonium nitrate discharged from the nuclear fuel manufacturing works and to recover nitric acid and ammonia. For denitrification they applied the operating method and the conditions of operation to make 0.4mM or less from NH{sub 4}NO{sub 3} waste water of 1.5 M by 3 stages of electrodialysis cells. To recover nitric acid and ammonium water, they separated HNO{sub 3} solution of 6 M and NH{sub 4}OH solution with one unit of electrolysis cell, then absorbed NH{sub 3} gas from NH{sub 4}OH solution with water and applied the condition of operation to recover 8 M NH{sub 4}OH solution. The authors demonstrated that treatment and recovery can be carried out stably with actual waste water with a system through the combination of previously mentioned electrodialysis cells, electrolysis cells and an ammonia gas absorber. At present they are planning a plant where NH{sub 4}NO{sub 3} waste water of 4,500 mol can be treated per day.

  20. Study on the Effect of Synthesis Temperature on the Structural, Surface Morphological and Optical Properties of Methyl Ammonium Lead Iodide Nanoparticles by Sol-Gel Method

    Science.gov (United States)

    Benazeera Beegum, K. A.; Paulose, Maria; Peter, V. J.; Raphael, Rakhy; Sreeja, V. G.; Anila, E. I.

    2016-09-01

    Lead halide perovskite solar cells have recently attracted tremendous attention because of their excellent photovoltaic efficiency. The quality and stability of perovskite films are critical for solar cells. We report the synthesis of methyl ammonium lead iodide (MAPbKI3) nanoparticles from methyl amine, hydroiodic acid and lead iodide by sol-gel method. Three powder samples of Methyl ammonium Lead Iodide were prepared at 50 °C, 90 °C, and 100 °C. The powder samples were characterised by X-ray diffraction (XRD), Diffuse reflectance spectroscopy (DRS), Scanning Electron Microscopy (SEM), Energy Dispersive Analysis of X- rays (EDAX) and Photoluminescence (PL). The presence of carbon, hydrogen and nitrogen were examined through CHN studies. The surface morphology, band gap, and elemental contents changes with temperature. The XRD pattern exhibited major reflections from (110), (220), (310), (224) and (314) planes in agreement with JCPDS file No: 00-021-1276, revealing tetragonal structure.

  1. Nitrate removal by organotrophic anaerobic ammonium oxidizing bacteria with C2/C3 fatty acid in upflow anaerobic sludge blanket reactors.

    Science.gov (United States)

    Liang, Yuhai; Li, Dong; Zhang, Xiaojing; Zeng, Huiping; Yang, Yin; Zhang, Jie

    2015-10-01

    In anaerobic ammonium oxidation (Anammox) process, a harsh ratio of nitrite to ammonia in influent was demanded, and the max nitrogen removal efficiency could only achieve to 89%, both of which limited the development of Anammox. The aim of this work was to study the nitrate removal by organotrophic anaerobic ammonium oxidizing bacteria (AAOB) with C2/C3 fatty acid in upflow anaerobic sludge blanket (UASB) reactors. In this study, organotrophic AAOB was successfully enriched by adding acetate and propionate with the total organic carbon to nitrogen (TOC/N) ratio of 0.1. In the condition of low substrate, the TN removal efficiency reached 90%, with the effluent TN of around 11.8 mg L(-1). After the addition of acetate and propionate, the predominant species in Anammox granular sludge transformed to Candidatus Jettenia that belonging to organotrophic AAOB from the Candidatus Kuenenia relating to general AAOB.

  2. Studies on Biquaternary Ammonium Salt Algaecide for Removing Red Tide Algae

    Institute of Scientific and Technical Information of China (English)

    刘洁生; 张珩; 杨维东; 高洁; 柯琼

    2004-01-01

    The paper deals with the removal and control of red tide algae, Phaeoecystis globosa and Alexandrium tamarense by biquaternary ammonium salt algaecide. The results show that the efficient concentration of biquaternary ammonium salt to control the two algaes in 96 h is 0.8 mg · L-1 and 0.4 mg · L-1, respectively. It is found that biquaternary ammonium salt has high efficiency and longer duration of action in the removal and control of algae.Biquaternary ammonium salt might be an excellent algaecide to control HAB.

  3. Formation and transformation of metastable double salts from the crystallization of mixed ammonium nitrate and ammonium sulfate particles.

    Science.gov (United States)

    Ling, Tsz Yan; Chan, Chak K

    2007-12-01

    Ammonium nitrate (AN) and ammonium sulfate (AS) are ubiquitous components of atmospheric aerosols. Thermodynamic models predict formation of pure (AN and AS) and double salts (3AN. AS and 2AN. AS) for the AN/AS system. Because of the high supersaturation at which a droplet crystallizes, metastable crystal formation is possible. In this study, the identity of the crystals formed from the crystallization of equimolar AN/AS mixed droplets was investigated in an electrodynamic balance coupled with a Raman spectroscopic system. Raman spectra of bulk AN/AS double salts possibly formed in this system are first reported for comparison with the single particle Raman results. The double-salt 3AN. AS, not predicted from thermodynamics, was observed in the freshly crystallized single particles. The degree of metastability can be different among several crystallization processes of the same particles. The metastable salt 3AN. AS gradually transformed into stable 2AN. AS, and the rate of such transformation increased with increasing relative humidity. This study illustrates the possibility of occurrence of metastable salts in atmospheric aerosols.

  4. Determination of the extractive capacity of para-tert butyl calix[8]arene octa-phosphinoylated towards uranyl ions from an aqueous-acidic-salty medium; Determinacion de la capacidad extractiva del p-ter-butilocalix[8]areno octa-fosfinoilado hacia iones uranilo de un medio acuo-acido salino

    Energy Technology Data Exchange (ETDEWEB)

    Serrano V, E. C.

    2011-07-01

    The extraction properties of octa-phosphinoylated para-tert butyl calix[8]arene (prepared in the laboratory) in chloroform towards uranyl ions from an aqueous-acidic-salty medium (HNO{sub 3}-3.5 NaNO{sub 3}) containing uranyl nitrate salt, was investigated. Two spectroscopic techniques UV/Vis and Luminescence were used for this study. The latter permitted analyze the fluorescence from the uranyl ions influenced by the surrounding medium. Both permitted to learn about the power of this calixarene as extractant towards the mentioned ions. Its extraction ability or capability using this calixarene at 5.91 x 10{sup -4} M towards the uranyl ions was 400% as determined by UV/Vis while fluorescence revealed 100% of uranyl ion extraction. A closed analysis of the results obtained by using these techniques revealed that the stoichiometry of the main extracted species was 1calixarene:2 uranyl ions. The loading capacity of the calixarene ligand towards the uranyl ions was also investigated using both techniques. UV/Vis resulted to be inadequate for quantifying exactly the loading capacity of the calixarene whereas luminescence was excellent indeed, using a 5.91 x 10{sup -4} M calixarene concentration, its loading capacity was 0.157 M of free uranyl ions from 0.161 M of uranyl ions present in the aqueous-acidic-salty medium. The extracts from the ability and capacity studies were concentrated to dryness, purified and the dried extracts were analyzed by infrared and neutron activation analysis. By these techniques it was demonstrated that during the extraction of the uranyl ions by the calixarene ligand they form thermodynamically and kinetically stable complexes, since in the solid state, the 1:2, calixarene; uranyl ions stoichiometry was kept with the minimum formula: (UO{sub 2}){sub 2}B{sub 8}bL{sup 8}(NO{sub 3}){sub 4}(H{sub 2}O){sub 4}CHCl{sub 3}(CH{sub 3}OH){sub 3} the methanol molecules come from its purification. It is proposed that B{sub 8}bL{sup 8} calixarene in

  5. Relationship of the vibrational frequency of the uranyl ion with the uranium electronegativity; Relacion de la frecuencia vibracional del ion uranilo con la electronegatividad del uranio

    Energy Technology Data Exchange (ETDEWEB)

    Rodriguez S, A.; Martinez Q, E

    1990-07-15

    It has been demonstrated that the vibrational asymmetric frequency of the uranyl ion, it experiences a consistent spectrochemical displacement with the variations of electronegativity of the uranium in their complexes. The values of the electronegativity of the uranium they were dear by means of calculations that it involves measures of those lengths of the connection uranium-oxygen, obtained by vibrational spectroscopy, effective nuclear charges and the Allred and Rochow equation. The results show the evidence of a natural order that relates to the vibrational frequency with the electronegativity of the uranium atom; settling down that if the electronegativity is graph against it bond length to the oxygen or to it frequency value, a simple relationship is obtained as a form to obtain clear responses in absence of complementary information. (Author)

  6. Standard test method for determination of bromine and chlorine in UF6 and uranyl nitrate by X-Ray fluorescence (XRF) spectroscopy

    CERN Document Server

    American Society for Testing and Materials. Philadelphia

    2001-01-01

    1.1 This method covers the determination of bromine (Br) and chlorine (Cl) in uranium hexafluoride (UF6) and uranyl nitrate solution. The method as written covers the determination of bromine in UF6 over the concentration range of 0.2 to 8 μg/g, uranium basis. The chlorine in UF6 can be determined over the range of 4 to 160 μg/g, uranium basis. Higher concentrations may be covered by appropriate dilutions. The detection limit for Br is 0.2 μg/g uranium basis and for Cl is 4 μg/g uranium basis. 1.2 This standard may involve hazardous materials, operations and equipment. This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use.

  7. Quantitative remote sensing of ammonium minerals, Cedar Mountains, Esmeralda County, Nevada

    Science.gov (United States)

    Baugh, William M.; Kruse, Fred A.

    1995-01-01

    Mineral-bound ammonium (NH4+) was discovered by the U.S. Geological Survey in the southern Cedar Mountains of Esmeralda County, Nevada in 1989. At 10 km in length, this site is 100 times larger than any previously known occurrence in volcanic rocks. The ammonium occurs in two hydrothermally altered, crystal-rich rhyolitic tuff units of Oligocene age, and is both structurally and stratigraphically controlled. This research uses Advanced Visible/Infrared Imaging Spectrometer (AVIRIS) data to quantitatively map the mineral-bound ammonium (buddingtonite) concentration in the altered volcanic rocks. Naturally occurring mineral-bound ammonium is fairly rare; however, it has been found to occur in gold-bearing hydrothermal deposits. Because of this association, it is thought that ammonium may be a useful too in exploration for gold and other metal deposits. Mineral-bound ammonium is produced when an ammonium ion (NH4+) replaces the alkali cation site (usually K+) in the crystal structure of silicate minerals such as feldspars, micas and clays. Buddingtonite is an ammonium feldspar. The ammonium originates in buried organic plant matter and is transported to the host rock by hydrothermal fluids. Ammonium alteration does not produce visible changes in the rock, and it is barely detectable with standard x-ray diffraction methods. It is clearly identified, however, by absorption features in short wave-infrared (SWIR) wavelengths (2.0 - 2.5 micrometers). The ammonium absorption features are believed to be caused by N-H vibrational modes and are analogous to hydroxyl (O-H) vibrational modes, only shifted slightly in wavelength. Buddingtonite absorption features in the near- and SWIR lie at 1.56, 2.02 and 2.12 micrometers. The feature at 2.12 micrometer is the strongest of the three and is the only one used in this study. The southern Cedar Mountains are sparsely vegetated and are an ideal site for a remote sensing study.

  8. Assessment of the potential for ammonium nitrate formation and reaction in Tank 241-SY-101

    Energy Technology Data Exchange (ETDEWEB)

    Pederson, L.R.; Bryan, S.A.

    1994-08-01

    Two principal scenarios by which ammonium nitrate may be formed were considered: (a) precipitation of ammonium nitrate in the waste, and (b) ammonium nitrate formation via the gas phase reaction of ammonia and nitrogen dioxide. The first of these can be dismissed because ammonium ions, which are necessary for ammonium nitrate precipitation, can exist only in negligibly small concentrations in strongly alkaline solutions. Gas phase reactions between ammonia, nitrogen dioxide, and water vapor in the gas phase represent the most likely means by which ammonium nitrate aerosols could be formed in Tank 241-SY-101. Predicted ammonium nitrate formation rates are largely controlled by the concentration of nitrogen dioxide. This gas has not been detected among those gases vented from the wastes using Fourier Transform Infrared Spectrometry (FTIR) or mass spectrometry. While detection limits for nitrogen dioxide have not been established experimentally, the maximum concentration of nitrogen dioxide in the gas phase in Tank 241-SY-101 was estimated at 0.1 ppm based on calculations using the HITRAN data base and on FTIR spectra of gases vented from the wastes. At 50 C and with 100 ppm ammonia also present, less than one gram of ammonium nitrate per year is estimated to be formed in the tank. To date, ammonium nitrate has not been detected on HEPA filters in the ventilation system, so any quantity that has been formed in the tank must be quite small, in good agreement with rate calculations. The potential for runaway exothermic reactions involving ammonium nitrate in Tank 241-SY-101 is minimal. Dilution by non-reacting waste components, particularly water, would prevent hazardous exothermic reactions from occurring within the waste slurry, even if ammonium nitrate were present. 41 refs.

  9. Effects of Dissolved Oxygen Tension and Ammonium Concentration on Polyhydroxybutyrate Synthesis from Cassava Starch by Bacillus cereus IFO 13690

    Directory of Open Access Journals (Sweden)

    Margono .

    2015-11-01

    Full Text Available generated by an Adobe application 11.5606 Attempting to get low price of raw material for producing polyhydroxybutyrate is always studied. Tapioca starch is one of the raw material with low price. The objective of this research was to study the effects of initial ammonium concentration and dissolved oxygen tension (doT on producing PHB by Bacillus cereus IFO 13690 with tapioca starch as the carbon source. This fermentation was carried out in 5 L fementors with a 2 L working volume, temperature of 30 oC, and agitation of 500 rpm. The pH medium was controlled at 5.6 after it came down from the initial pH of 6.8. Meanwhile, the initial doT was 100 % air saturation and also came down to and maintained at doT of experiment, i.e. 1 , 5 , or 10 % air saturation. The best result was obtained when the initial ammonium concentration was 5 g/L and the doT value maintained at 5 % air saturation. By this conditions, the cell growth reached 5,457 g cell dry weight/L containing PHB of 2.42 % cell dry weigh after 29 hours fermentation. Normal 0 36 false false false

  10. Activated Carbon, Carbon Nanofiber and Carbon Nanotube Supported Molybdenum Carbide Catalysts for the Hydrodeoxygenation of Guaiacol

    Directory of Open Access Journals (Sweden)

    Eduardo Santillan-Jimenez

    2015-03-01

    Full Text Available Molybdenum carbide was supported on three types of carbon support—activated carbon; multi-walled carbon nanotubes; and carbon nanofibers—using ammonium molybdate and molybdic acid as Mo precursors. The use of activated carbon as support afforded an X-ray amorphous Mo phase, whereas crystalline molybdenum carbide phases were obtained on carbon nanofibers and, in some cases, on carbon nanotubes. When the resulting catalysts were tested in the hydrodeoxygenation (HDO of guaiacol in dodecane, catechol and phenol were obtained as the main products, although in some instances significant amounts of cyclohexane were produced. The observation of catechol in all reaction mixtures suggests that guaiacol was converted into phenol via sequential demethylation and HDO, although the simultaneous occurrence of a direct demethoxylation pathway cannot be discounted. Catalysts based on carbon nanofibers generally afforded the highest yields of phenol; notably, the only crystalline phase detected in these samples was Mo2C or Mo2C-ζ, suggesting that crystalline Mo2C is particularly selective to phenol. At 350 °C, carbon nanofiber supported Mo2C afforded near quantitative guaiacol conversion, the selectivity to phenol approaching 50%. When guaiacol HDO was performed in the presence of acetic acid and furfural, guaiacol conversion decreased, although the selectivity to both catechol and phenol was increased.

  11. Ammonium Chloride Ingestion Attenuates Exercise-Induced mRNA Levels in Human Muscle.

    Directory of Open Access Journals (Sweden)

    Johann Edge

    Full Text Available Minimizing the decrease in intracellular pH during high-intensity exercise training promotes greater improvements in mitochondrial respiration. This raises the intriguing hypothesis that pH may affect the exercise-induced transcription of genes that regulate mitochondrial biogenesis. Eight males performed 10x2-min cycle intervals at 80% VO2speak intensity on two occasions separated by ~2 weeks. Participants ingested either ammonium chloride (ACID or calcium carbonate (PLA the day before and on the day of the exercise trial in a randomized, counterbalanced order, using a crossover design. Biopsies were taken from the vastus lateralis muscle before and after exercise. The mRNA level of peroxisome proliferator-activated receptor co-activator 1α (PGC-1α, citrate synthase, cytochome c and FOXO1 was elevated at rest following ACID (P0.05; the difference in PGC-1α mRNA content 2 h post-exercise between ACID and PLA was not significant (P = 0.08. Thus, metabolic acidosis abolished the early post-exercise increase of PGC-1α mRNA and the mRNA of downstream mitochondrial and glucose-regulating proteins. These findings indicate that metabolic acidosis may affect mitochondrial biogenesis, with divergent responses in resting and post-exercise skeletal muscle.

  12. Surface chemical study on the covalent attachment of hydroxypropyltrimethyl ammonium chloride chitosan to titanium surfaces

    Energy Technology Data Exchange (ETDEWEB)

    Xu Xiaofen; Wang Ling [School of Pharmacy, Shanghai Jiao Tong University, 800 Dong-chuan Road, Shanghai 200240 (China); Guo Shengrong, E-mail: srguo@sjtu.edu.cn [School of Pharmacy, Shanghai Jiao Tong University, 800 Dong-chuan Road, Shanghai 200240 (China); Lei Lei [School of Pharmacy, Shanghai Jiao Tong University, 800 Dong-chuan Road, Shanghai 200240 (China); Tang Tingting, E-mail: tingtingtang@hotmail.com [Shanghai Key Laboratory of Orthopedic Implant, Department of Orthopedic Surgery, Shanghai Ninth People' s Hospital, Shanghai Jiaotong University School of Medicine (China)

    2011-10-01

    An anti-microbial and bioactive coating could not only reduce the probability of infection related to titanium implants but also support the growth of surrounding osteogenic cells. Our previous study has showed that hydroxypropyltrimethyl ammonium chloride chitosan (HACC) with a DS (degrees of substitution) of 18% had improved solubility and significantly higher antibacterial activities against three bacteria which were usually associated with infections in orthopaedics. In the current study, HACC with a DS of 18% coating was bonded to titanium surface by a three-step process. The titanium surface after each individual reaction step was analyzed by X-ray photoelectron spectroscopy (XPS) and attenuated total reflection (ATR) of Fourier-transformed infrared (FT-IR) spectroscopy. The XPS results demonstrated that there were great changes in the atomic ratios of C/Ti, O/Ti, and N/Ti after each reaction step. The XPS high resolution and corresponding devolution spectra of carbon, oxygen, nitrogen, and titanium were also in good coordination with the anticipated reaction steps. Additionally, the absorption bands around 3365 cm{sup -1} (-OH vibration), 1664 cm{sup -1} (Amide I), 1165 cm{sup -1} ({nu}{sub as}, C-O-C bridge), and the broad absorption bands between 958 cm{sup -1} and 1155 cm{sup -1} (skeletal vibrations involving the C-O stretching of saccharide structure of HACC) verified that HACC was successfully attached to titanium surface.

  13. Fire Performance of Plywood Treated with Ammonium Polyphosphate and 4A Zeolite

    Directory of Open Access Journals (Sweden)

    Mingzhi Wang

    2014-07-01

    Full Text Available Plywood samples treated with ammonium polyphosphate (APP and 4A zeolite were prepared to investigate the effect of zeolite on wood’s burning behavior using a cone calorimeter under a heat flux of 35 kW/m2. Results showed that APP decreased the heat release rate (HRR, total heat release (THR, and mass loss rate (MLR of treated plywood. However, APP significantly increased the total smoke release (TSR and carbon monoxide (CO yield. The addition of 4A zeolite reduced the HRR, peak HRR, and THR of the plywood treated with only APP. The second HRR peak in a typical plywood curve diminished with the addition of as little as 2% 4A zeolite. The average specific extinction area (ASEA and CO yield decreased significantly with the presence of zeolite in the APP. The ignition time did not change significantly and the TSR increased when zeolite was present. Thus, a suitable amount of 4A zeolite works synergistically with APP in promoting flame retardancy in flame retardant plywood.

  14. Synergy of ammonium chloride and moisture on perovskite crystallization for efficient printable mesoscopic solar cells

    Science.gov (United States)

    Rong, Yaoguang; Hou, Xiaomeng; Hu, Yue; Mei, Anyi; Liu, Linfeng; Wang, Ping; Han, Hongwei

    2017-01-01

    Organometal lead halide perovskites have been widely used as the light harvester for high-performance solar cells. However, typical perovskites of methylammonium lead halides (CH3NH3PbX3, X=Cl, Br, I) are usually sensitive to moisture in ambient air, and thus require an inert atmosphere to process. Here we demonstrate a moisture-induced transformation of perovskite crystals in a triple-layer scaffold of TiO2/ZrO2/Carbon to fabricate printable mesoscopic solar cells. An additive of ammonium chloride (NH4Cl) is employed to assist the crystallization of perovskite, wherein the formation and transition of intermediate CH3NH3X·NH4PbX3(H2O)2 (X=I or Cl) enables high-quality perovskite CH3NH3PbI3 crystals with preferential growth orientation. Correspondingly, the intrinsic perovskite devices based on CH3NH3PbI3 achieve an efficiency of 15.6% and a lifetime of over 130 days in ambient condition with 30% relative humidity. This ambient-processed printable perovskite solar cell provides a promising prospect for mass production, and will promote the development of perovskite-based photovoltaics. PMID:28240286

  15. Trophic mode conversion and nitrogen deprivation of microalgae for high ammonium removal from synthetic wastewater.

    Science.gov (United States)

    Wang, Jinghan; Zhou, Wenguang; Yang, Haizhen; Wang, Feng; Ruan, Roger

    2015-11-01

    In this study, a well-controlled three-stage process was proposed for high ammonium removal from synthetic wastewater using selected promising microalgal strain UMN266. Three trophic modes (photoautotrophy, heterotrophy, and mixotrophy), two N sufficiency conditions (N sufficient and N deprived), two inoculum modes (photoautotrophic and heterotrophic), and different NH4(+)-N concentrations were compared to investigate the effect of trophic mode conversion and N deprivation on high NH4(+)-N removal by UMN266. Results showed that photoautotrophic inoculum with trophic mode conversion from heterotrophy to photoautotrophy and N deprivation in Stage 2 turned was the optimum plan for NH4(+)-N removal, and average removal rates were 12.4 and 19.1mg/L/d with initial NH4(+)-N of 80 and 160mg/L in Stage 3. Mechanism investigations based on algal biomass carbon (C) and N content, cellular composition, and starch content confirmed the above optimum plan and potential of UMN266 as bioethanol feedstock.

  16. Uranyl Nitrate Flow Loop

    Energy Technology Data Exchange (ETDEWEB)

    Ladd-Lively, Jennifer L [ORNL

    2008-10-01

    The objectives of the work discussed in this report were to: (1) develop a flow loop that would simulate the purified uranium-bearing aqueous stream exiting the solvent extraction process in a natural uranium conversion plant (NUCP); (2) develop a test plan that would simulate normal operation and disturbances that could be anticipated in an NUCP; (3) use the flow loop to test commercially available flowmeters for use as safeguards monitors; and (4) recommend a flowmeter for production-scale testing at an NUCP. There has been interest in safeguarding conversion plants because the intermediate products [uranium dioxide (UO{sub 2}), uranium tetrafluoride (UF{sub 4}), and uranium hexafluoride (UF{sub 6})] are all suitable uranium feedstocks for producing special nuclear materials. Furthermore, if safeguards are not applied virtually any nuclear weapons program can obtain these feedstocks without detection by the International Atomic Energy Agency (IAEA). Historically, IAEA had not implemented safeguards until the purified UF{sub 6} product was declared as feedstock for enrichment plants. H. A. Elayat et al. provide a basic definition of a safeguards system: 'The function of a safeguards system on a chemical conversion plant is in general terms to verify that no useful nuclear material is being diverted to use in a nuclear weapons program'. The IAEA now considers all highly purified uranium compounds as candidates for safeguarding. DOE is currently interested in 'developing instruments, tools, strategies, and methods that could be of use to the IAEA in the application of safeguards' for materials found in the front end of the nuclear fuel cycle-prior to the production of the uranium hexafluoride or oxides that have been the traditional starting point for IAEA safeguards. Several national laboratories, including Oak Ridge, Los Alamos, Lawrence Livermore, and Brookhaven, have been involved in developing tools or techniques for safeguarding conversion plants. This study was sponsored by the U.S. Department of Energy (DOE) NA-241, Office of Dismantlement and Transparency.

  17. Rotavirus gastroenteritis-associated urinary ammonium acid urate crystals.

    Science.gov (United States)

    Yokoyama, Tadafumi; Sugimoto, Naotoshi; Kato, Eiji; Ohta, Kazuhide; Ishikawa, Sayaka; Ueno, Kazuyuki; Shimizu, Masaki; Yachie, Akihiro

    2015-01-01

    Although ammonium acid urate (AAU) calculi are extremely rare renal stone components, it was recently found that many urinary tract calculi that cause post-renal renal failure in rotavirus (RV) gastroenteritis are AAU calculi. The mechanism of AAU calculi development in RV gastroenteritis has not been fully elucidated. We analyzed data from eight RV gastroenteritis patients who transiently had AAU crystals in their urinary sediment. In these patients, formation of AAU crystals occurred earlier than the formation of AAU calculi. No difference was observed in serum and urine uric acid levels between RV gastroenteritis patients with or without AAU crystals. Interestingly, fractional excretion of sodium was extremely low among patients with AAU crystals. These results suggest that the formation of AAU crystals might not be due to excretion of uric acid, but excretion of sodium.

  18. Review of Options for Ammonia/Ammonium Management

    Energy Technology Data Exchange (ETDEWEB)

    Nash, C. A. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL)

    2016-05-06

    This report is a review of literature supporting practical ammonia/ammonium destruction processes. Melter research supporting Hanford Low Activity Waste (LAW) glass production has shown that significant amounts of ammonia will be in the melter offgas condensate. Further work with secondary waste forms indicates the potential need to remove the ammonia, perhaps by an oxidative process. This review finds likely practical chemical methods to oxidize ammonia in aqueous solution at moderate temperatures and atmospheric pressure, using easily obtained reagents. Leading candidates include nitrite oxidation to produce nitrogen gas, various peroxide oxidative processes, and air stripping. This work reviews many other processes and provides reasoning to not consider those processes further for this application.

  19. Synthesis of tetramethyl ammonium hydroxide by cell diaphragm electrolytic method

    Institute of Scientific and Technical Information of China (English)

    2005-01-01

    Under the conditions of tetramethyl ammonia chloride (TMAC) used as starting material, Ti-based Dimensionally Stable Anode (DSA), stainless steel used as cathode and Nafion 900 cation membrane as cell diaphragm, this paper studies the synthesis of tetramethyl ammonium hydroxide (TMAH) by cell diaphragm electrolytic method, examining not only the effects of current density, concentration of starting material and cell temperature, on the product purity and current efficiency, but also the effects of electrolyte circulation rate on the service life of Ti-based DSA.The experiment puts forward an optimum processing condition, and experimental findings show that preparing TMAH by using this technique can obtain a current efficiency 74.7 % and get product with a purity greater than 99.9%.

  20. Computational Modeling of Degradation of Substituted Benzyltrimethyl Ammonium: Preprint

    Energy Technology Data Exchange (ETDEWEB)

    Long, H.; Pivovar, B. S.

    2014-09-01

    The degradation of cations on the alkaline exchange membranes is the major challenge for alkaline membrane fuel cells. In this paper, we investigated the degradation barriers by density functional theory for substituted benzyltrimethyl ammonium (BTMA+) cations, which is one of the most commonly used cations for alkaline exchange membranes. We found that substituted cations with electron-releasing substituent groups at meta-position of the benzyl ring could result in improved degradation barriers. However, after investigating more than thirty substituted BTMA+ cations with ten different substituent groups, the largest improvement of degradation barriers is only 1.6 kcal/mol. This implies that the lifetime of alkaline membrane fuel cells could increase from a few months to a few years by using substituted BTMA+ cations, an encouraging but still limited improvement for real-world applications.

  1. Integrated Data Collection Analysis (IDCA) Program — Ammonium Nitrate

    Energy Technology Data Exchange (ETDEWEB)

    Sandstrom, Mary M. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Brown, Geoffrey W. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Preston, Daniel N. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Pollard, Colin J. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Warner, Kirstin F. [Naval Surface Warfare Center (NSWC), Indian Head, MD (United States). Indian Head Division; Sorensen, Daniel N. [Naval Surface Warfare Center (NSWC), Indian Head, MD (United States). Indian Head Division; Remmers, Daniel L. [Naval Surface Warfare Center (NSWC), Indian Head, MD (United States). Indian Head Division; Phillips, Jason J. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Shelley, Timothy J. [Bureau of Alcohol, Tobacco and Firearms, Redstone Arsenal, AL (United States); Reyes, Jose A. [Applied Research Associates, Tyndall AFB, FL (United States); Hsu, Peter C. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Reynolds, John G. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)

    2013-05-17

    The Integrated Data Collection Analysis (IDCA) program is conducting a proficiency study for Small- Scale Safety and Thermal (SSST) testing of homemade explosives (HMEs). Described here are the results for impact, friction, electrostatic discharge, and differential scanning calorimetry analysis of ammonium nitrate (AN). AN was tested, in most cases, as both received from manufacturer and dried/sieved. The participants found the AN to be: 1) insensitive in Type 12A impact testing (although with a wide range of values), 2) completely insensitive in BAM friction testing, 3) less sensitive than the RDX standard in ABL friction testing, 4) less sensitive than RDX in ABL ESD testing, and 5) less sensitive than RDX and PETN in DSC thermal analyses.

  2. Studies on a Cationically Modified Quaternary Ammonium Salt of Lignin

    Institute of Scientific and Technical Information of China (English)

    YANG Ai-li; JIANG Wen-ju

    2007-01-01

    A new quaternary ammonium salt monomer was synthesized and a quaternary amination of lignin( noted as QL),with the monomer was carried out by grafting copolymerization. The products were characterized by Fourier Transform Infrared spectroscopy(FTIR). The experimental results indicate that the yield of the monomer was 99.06%, and the conversion of the monomer and the grafting yield of QL were 93.69% and 185.78%, respectively. The feasibility of QL as the fiocculant to be applied in color removal of five artificial dyes, eriochrome black T( dye A), gongo red( dye B), direct fast black G (dye C), cuprofix blue green B (dye D), and acid black ATT (dye E) was examined.Results show that QL exhibits the favorable flocculation performance and high stability.

  3. Antibacterial effect of composite resins containing quaternary ammonium polyethyleneimine nanoparticles

    Energy Technology Data Exchange (ETDEWEB)

    Yudovin-Farber, Ira [Hebrew University of Jerusalem, Department of Medicinal Chemistry and Natural Products, School of Pharmacy, Faculty of Medicine (Israel); Beyth, Nurit; Weiss, Ervin I. [Hebrew University of Jerusalem, Department of Prosthodontics, Faculty of Dentistry (Israel); Domb, Abraham J., E-mail: avid@ekmd.huji.ac.i [Hebrew University of Jerusalem, Department of Medicinal Chemistry and Natural Products, School of Pharmacy, Faculty of Medicine (Israel)

    2010-02-15

    Quaternary ammonium polyethyleneimine (QA-PEI)-based nanoparticles were synthesized by crosslinking with dibromopentane followed by N-alkylation with various alkyl halides and further N-methylation with methyl iodide. Insoluble pyridinium-type particles were prepared by suspension polymerization of 4-vinyl pyridine followed by N-alkylation with alkyl halides. Polyamine-based nanoparticles embedded in restorative composite resin at 1% w/w were tested for antibacterial activity against Streptococcus mutans using direct contact test. Activity analysis revealed that the alkyl chain length of the QA-PEI nanoparticles plays a significant role in antibacterial activity of the reagent. The most potent compound was octyl-alkylated QA-PEI embedded in restorative composite resin at 1% w/w that totally inhibited S. mutans growth in 3-month-aged samples. This data indicates that restorative composite resin with antibacterial properties can be produced by the incorporation of QA-PEI nanoparticles.

  4. Ammonium nitrate emulsion : physical properties and decomposition using thermal methods

    Energy Technology Data Exchange (ETDEWEB)

    Feng, H.; Goldthorp, S.; Singh, S.; Turcotte, R.

    2009-05-15

    This presentation discussed methods of determining the physical properties and decomposition rates of commercial water-based explosives. Ammonium nitrate emulsions can explode when heated to critical temperatures or when a localized thermal energy deposition occurs. An accelerating rate calorimeter (ARC) was used to investigate the emulsion under adiabatic conditions. Simultaneous mass spectroscopy (MS) Fourier Transform Infrared (FTIR) and differential scanning calorimetry (DSC) techniques were used to conduct an evolved gas analysis. Results of the analysis demonstrated that the AN emulsions have ARC onset temperatures of approximately 220 degrees C. The mass loss reaction occurred in 2 steps. The initial step was related to water evaporation and oil phase volatilization. The second step was related to AN decomposition in a closed system, and AN dissociation in an open system. tabs., figs.

  5. Ammonium derivatives of chromenones and quinolinones as lead antimicrobial agents

    Indian Academy of Sciences (India)

    Shilpi Gupta; Seema Singh; Abha Kathuria; Manish Kumar; Sweta Sharma; Ram Kumar; Virinder S Parmar; Bharat Singh; Anjali Gupta; Erik Van Der Eycken; Gainda L Sharma; Sunil K Sharma

    2012-03-01

    A series of novel ammonium derivatives were synthesized and examined for their antimicrobial efficacy. Comparison of antimicrobial spectrum revealed that compounds 9, 11, 16 and 23 had strong potential against pathogens in vitro. Cytotoxicity results showed compound 9 to be least toxic, it is non-toxic to A549 and U87 cells in MTT assay and exhibits marginal toxicity (15-20%) to human erythrocytes at a concentration of 1000 g/ml as compared to 100% lysis of cells by 31.25 g/ml of the standard drug amphotericin B. This compound has MIC values in the range of 1.95-31.25 g/disc in DDA against different pathogens and may considered to be an important lead antimicrobial molecule for further exploration.

  6. Polishing of quartz by rapid etching in ammonium bifluoride.

    Science.gov (United States)

    Vallin, Orjan; Danielsson, Rolf; Lindberg, Ulf; Thornell, Greger

    2007-07-01

    The etch rate and surface roughness of polished and lapped AT-cut quartz subjected to hot (90, 110, and 130 degrees C), concentrated (50, 65, 80 wt %) ammonium bi-fluoride have been investigated. Having used principal component analysis to verify experimental solidity and analyze data, we claim with confidence that this parameter space does not, as elsewhere stated, allow for a polishing effect or even a preserving setting. Etch rates were found to correlate well, and possibly logarithmically, with temperature except for the hottest etching applied to lapped material. Roughness as a function of temperature and concentration behaved well for the lapped material, but lacked systematic variation in the case of the polished material. At the lowest temperature, concentration had no effect on etch rate or roughness. Future efforts are targeted at temperatures and concentrations closer to the solubility limit.

  7. Polymerization and photochromism of ammonium molybdate in porous glass

    Science.gov (United States)

    Pak, V. N.; Borisov, A. N.

    2016-08-01

    Modification of porous glass (PG) plates is carried out by impregnation with aqueous solutions of ammonium molybdate (NH4)2MoO4 with subsequent removal of water at 120°C. A long-wavelength shift of absorption spectra upon accumulation of the salt in PG indicates polymerization of MoO 4 2- anions at low concentrations of the encapsulated salt. Photochromism manifests itself as the anionic forms in PG become larger. UV irradiation of the modified plates causes enhancement of continuous absorption in the visible range. The proposed mechanism of photoreduction of the polianions in PG involves the removal of oxygen atoms from the bridging-Mo-O-Mo-bonds and stabilization of the colored forms by means of conjugation of the electrons released from the 4 d-levels of pentavalent molybdenum.

  8. Crystal structure of tris-(hydroxyl-ammonium) orthophosphate.

    Science.gov (United States)

    Leinemann, Malte; Jess, Inke; Boeckmann, Jan; Näther, Christian

    2015-11-01

    The crystal structure of the title salt, ([H3NOH](+))3·[PO4](3-), consists of discrete hydroxyl-ammonium cations and ortho-phos-phate anions. The atoms of the cation occupy general positions, whereas the anion is located on a threefold rotation axis that runs through the phospho-rus atom and one of the phosphate O atoms. In the crystal structure, cations and anions are linked by inter-molecular O-H⋯O and N-H⋯O hydrogen bonds into a three-dimensional network. Altogether, one very strong O-H⋯O, two N-H⋯O hydrogen bonds of medium strength and two weaker bifurcated N-H⋯O inter-actions are observed.

  9. Antibacterial effect of composite resins containing quaternary ammonium polyethyleneimine nanoparticles

    Science.gov (United States)

    Yudovin-Farber, Ira; Beyth, Nurit; Weiss, Ervin I.; Domb, Abraham J.

    2010-02-01

    Quaternary ammonium polyethyleneimine (QA-PEI)-based nanoparticles were synthesized by crosslinking with dibromopentane followed by N-alkylation with various alkyl halides and further N-methylation with methyl iodide. Insoluble pyridinium-type particles were prepared by suspension polymerization of 4-vinyl pyridine followed by N-alkylation with alkyl halides. Polyamine-based nanoparticles embedded in restorative composite resin at 1% w/w were tested for antibacterial activity against Streptococcus mutans using direct contact test. Activity analysis revealed that the alkyl chain length of the QA-PEI nanoparticles plays a significant role in antibacterial activity of the reagent. The most potent compound was octyl-alkylated QA-PEI embedded in restorative composite resin at 1% w/w that totally inhibited S. mutans growth in 3-month-aged samples. This data indicates that restorative composite resin with antibacterial properties can be produced by the incorporation of QA-PEI nanoparticles.

  10. Continuous electrolytic decarbonation and recovery of a carbonate salt solution from a metal-contaminated carbonate solution.

    Science.gov (United States)

    Kim, Kwang-Wook; Kim, Yeon-Hwa; Lee, Se-Yoon; Lee, Eil-Hee; Song, Kyusuk; Song, Kee-Chan

    2009-11-15

    This work studied the characteristic changes of a continuous electrolytic decarbonation and recovery of a carbonate salt solution from a metal-contaminated carbonate solution with changes of operational variables in an electrolytic system which consisted of a cell-stacked electrolyzer equipped with a cation exchange membrane and a gas absorber. The system could completely recover the carbonate salt solution from a uranyl carbonato complex solution in a continuous operation. The cathodic feed rate could control the carbonate concentration of the recovered solution and it affected the most transient pH drop phenomenon of a well type within the gas absorber before a steady state was reached, which caused the possibility of a CO(2) gas slip from the gas absorber. The pH drop problem could be overcome by temporarily increasing the OH(-) concentration of the cathodic solution flowing down within the gas absorber only during the time required for a steady state to be obtained in the case without the addition of outside NaOH. An overshooting peak of the carbonate concentration in the recovered solution before a steady state was observed, which was ascribed to the decarbonation of the initial solution filled within the stacked cells by a redundant current leftover from the complete decarbonation of the feeding carbonate solution.

  11. Cold Case: Radar investigation of ammonium sulfate cryovolcanism on Titan

    Science.gov (United States)

    Thomann, C.; Hayes, A. G.; Hofgartner, J.; Lunine, J. I.; Le Gall, A.

    2012-12-01

    The detection of a large tidal k2 value from Cassini [1] constitutes very strong evi-dence for a subcrustal ocean, most plausibly dominated by water. However, the secondary constituents are not known. One interesting possibility that has received scant attention in analysis of surface data sets is that the ocean contain aqueous ammonium sulfates, which erupted on the surface in the past to create vast, smooth plains [2]. We adopt the hypothesis that the undifferentiated plains—the "bland-lands" in the mid-latitudes of Titan—are these deposits, and test it using radiometry with SAR data. Lopez et al (this conference) investigate the global distribution and possible origin of this type of unit. We extracted SAR and radiometry-during-SAR data sets from the PDS, and pro-duced maps of brightness temperatures. The SAR imagery was used to identify locations where crossovers exist -some of which are in the undifferentiated plains--and hence where brightness temperatures at different incidence angles are available. We derived emissivities from the data using a simple radiometric model [3] to ac-count for the brightness temperature differences as a function of surface roughness, volume scattering and emissivity. We test the hypothesis by assessing whether the derived emissivities and volume scattering in the bland-lands are consistent with the model cryoclastic ash of ice and ammonium sulfate proposed in [2], distinct from that in other terrains. [1] L. Iess, R.A. Jacobson, M. Ducci, D.J. Stevenson, J.I. Lunine, J.W. Armstrong, S.W. Asmar, P. Racioppa, N.J. Rappaport, P. Tortora, Science, 337, 457 (2012). [2] A.D. Fortes, P.M. Grinrod, S.K. Trickett, L. Vocadlo. Icarus, 188, 139 (2007). [3] T.L. White and J.R. Cogdell. The Moon, 6, 235 (1973).

  12. Modeling the spectral optical properties of ammonium sulfate and biomass burning aerosols

    Energy Technology Data Exchange (ETDEWEB)

    Grant, K.E.; Chuang, C.C.; Grossman, A.S.; Penner, J.E. [Michigan Univ., Ann Arbor, MI (United States)

    1997-09-01

    The importance of including the global and regional radiative effects of aerosols in climate models has increasingly been realized. Accurate modeling of solar radiative forcing due to aerosols from anthropogenic sulfate and biomass burning emissions requires adequate spectral resolution and treatment of spatial and temporal variability. The variation of aerosol spectral optical properties with local relative humidity and dry aerosol composition must be considered. Because the cost of directly including Mie calculations within a climate model is prohibitive, parameterizations from offline calculations must be used. Starting from a log-normal size distribution of dry ammonium sulfate, we developed optical properties for tropospheric sulfate aerosol at 15 relative humidities up to 99 percent. The resulting aerosol size distributions were then used to calculate bulk optical properties at wavelengths between 0.175 {micro}m and 4 {micro}m. Finally, functional fits of optical properties were made for each of 12 wavelength bands as a function of relative humidity. Significant variations in optical properties occurred across the total solar spectrum. Relative increases in specific extinction and asymmetry factor with increasing relative humidity became larger at longer wavelengths. Significant variation in single-scattering albedo was found only in the longest near-IR band. This is also the band with the lowest albedo. A similar treatment was done for aerosols from biomass burning. In this case, size distributions were taken as having two carbonaceous size modes and a larger dust mode. The two carbonaceous modes were considered to be humidity dependent. Equilibrium size distributions and compositions were calculated for 15 relative humidities and five black carbon fractions. Mie calculations and Chandrasekhar averages of optical properties were done for each of the resulting 75 cases. Finally, fits were made for each of 12 spectral bands as functions of relative humidity

  13. In Situ Dissimilatory Nitrate Reduction to Ammonium in a Paddy Soil Fertilized with Liquid Cattle Waste

    Institute of Scientific and Technical Information of China (English)

    LU Wei-Wei; S.RIYA; ZHOU Sheng; M.HOSOMI; ZHANG Hai-Lin; SHI Wei-Ming

    2012-01-01

    Most studies on dissimilatory nitrate reduction to ammonium (DNRA) in paddy soils were conducted in the laboratory and in situ studies are in need for better understanding of the DNRA process.In this study,in situ incubations of soil DNRA using 15N tracer were carried out in paddy fields under conventional water (CW) and low water (LW) managements to explore the potential of soil DNRA after liquid cattle waste (LCW) application and to investigate the impacts of soil redox potential (Eh) and labile carbon on DNRA.DNRA rates ranged from 3.06 to 10.40 mg N kg -1 dry soil d-1,which accounted for 8.55%-12.36% and 3.88%-25.44% of consunption of added NO3-15N when Eh at 5 cm soil depth ranged from 230 to 414 mV and -225 to -65 mV,respectively.DNRA rates showed no significant difference in paddy soils under two water managements although soil Eh and/or dissolved organic carbon (DOC) were more favorable for DNRA in the paddy soil under CW management 1 d before,or 5 and 7 d after LCW application.Soil DNRA rates were negatively correlated with soil Eh (P < 0.05,n =5) but positively correlated with soil DOC (P < 0.05,n =5) in the paddy soil under LW management,while no significant correlations were shown in the paddy soil under CW management.The potential of DNRA measured in situ was consistent with previous laboratory studies; and the controlling factors of DNRA in paddy soils might be different under different water managements,probably due to the presence of different microfloras of DNRA.

  14. Ammonium addition inhibits 13C-methane incorporation into methanotroph membrane lipids in a freshwater sediment

    NARCIS (Netherlands)

    Nold, s.c.; Boschker, H.T.S.; Pel, R.; Laanbroek, H.J.

    1999-01-01

    To investigate the effect of ammonium addition on the species composition and activity of freshwater methane oxidizing bacteria, intact sediment cores were labeled with (CH4)-C-13 and incubated under ambient and elevated ammonium concentrations. After 7 days, methanotroph activity was assessed by qu

  15. Clinoptilolite-based mixed matrix membranes for the selective recovery of potassium and ammonium

    NARCIS (Netherlands)

    Casadella, A.; Kuntke, P.; Schaetzle, O.; Loos, K.

    2016-01-01

    . A clinoptilolite-based mixed matrix membrane (MMM) was developed and studied for the selective recovery of ammonium and potassium. Adsorption of sodium (Na+), potassium (K+) and ammonium (NH4+) was investigated with single salt and equimolar salt solution under static and dynamic conditions. Furth

  16. Ammonium sorption from aqueous solutions by the natural zeolite Transcarpathian clinoptilolite studied under dynamic conditions.

    Science.gov (United States)

    Sprynskyy, Myroslav; Lebedynets, Mariya; Terzyk, Artur P; Kowalczyk, Piotr; Namieśnik, Jacek; Buszewski, Bogusław

    2005-04-15

    The scope of this study is ammonium-ion uptake from synthetic aqueous solutions onto raw and pretreated forms of the natural zeolite Transcarpathian clinoptilolite under dynamic conditions. Hydrogen ions displaced exchangeable cations on the clinoptilolite in distilled water (sodium ions) and hydrochloric acid (sodium, potassium, and calcium ions) and destroyed the zeolite framework structure in the last case. Ammonium uptake onto the zeolite occurs by exchange with Na(+), Ca(2+), and K(+) ions. Although Na(+) ions were observed to be more easily exchanged for both hydrogen and ammonium ions, the role of Ca(2+) ions increased with zeolite saturation by NH(+)(4) ions. The maximum sorption capacity of the clinoptilolite toward NH(+)(4) ions, estimated under dynamic conditions, is significantly higher than that measured under static conditions; proximity of the values of a distribution coefficient and a retardation factor for different conditions (215-265 dm(3)/kg and 979-1107, respectively) allows us to use these parameters to model ammonium uptake onto the clinoptilolite. Slowing down or interruption in filtration resulted in the improvement of ammonium sorption properties of the zeolite. The ammonium removal improves with use of the finer fractions of the clinoptilolite up to 0.35 mm. A recycling study results confirmed the importance of external diffusion for ammonium sorption by the clinoptilolite. Preliminary treatment of the sorbent confirmed the predominant importance of the ion-exchange mechanism. The advantage of prior NaCl treatment of the clinoptilolite in improvement of ammonium removal over the other techniques was shown.

  17. Novel carbohydrate-based chiral ammonium ionic liquids derived from isomannide

    DEFF Research Database (Denmark)

    Kumar, Vineet; Pei, Cao; Olsen, Carl E.

    2008-01-01

    This report describes the synthesis and characterization of novel carbohydrate-based chiral ammonium ionic liquids using isomannide as a biorenewable substrate. The diastereomeric interactions of these chiral ammonium ionic liquids with racemic Mosher's acid salt have been studied using NMR, whic...

  18. Electroantennogram and behavioral responses of Anastrepha suspensa (Diptera: Tephritidae) to putrescine and ammonium bicarbonate lures.

    Science.gov (United States)

    Kendra, Paul E; Montgomery, Wayne S; Epsky, Nancy D; Heath, Robert R

    2009-08-01

    At present, the most effective synthetic lures for pest Anastrepha fruit flies are multicomponent blends that include ammonia and the diamine synergist putrescine (1,4-diaminobutane). Both chemicals generally have been regarded as protein cues that result in female-biased attraction. Using electroantennography (EAG) and flight tunnel bioassays, this study evaluated response of the Caribbean fruit fly, Anastrepha suspensa (Loew) to vapors released from commercial lure formulations of ammonium bicarbonate and putrescine. Over a range of doses tested, EAG response to ammonium bicarbonate was equivalent for both sexes, but female response was significantly greater than male response to putrescine and to a 1:1 mixture of ammonium bicarbonate and putrescine. Amplitude of EAG response to the mixture was approximately equal to the summation of responses to the individual substrates. Using a fixed dose of substrate, EAG measurements from females 1-14 d old indicated that antennal sensitivity to both lures varied according to physiological state of the fly. Peak response to ammonium bicarbonate was recorded from immature females, peak response to putrescine from sexually mature females. In bioassays, more females were captured with ammonium bicarbonate plus putrescine than with ammonium bicarbonate alone. This difference was not observed in males, resulting in a higher female to male ratio in captures with ammonium bicarbonate plus putreseine (3:1) versus ammonium bicarbonate alone (1:1). Results suggest that separate olfactory receptors are involved in detection of the two semiochemicals, and that the putrescine component is primarily responsible for the female-biased attraction.

  19. 40 CFR 721.10154 - Quaternary ammonium compounds, dicoco alkyldimethyl, chlorides, reaction products with silica.

    Science.gov (United States)

    2010-07-01

    ... 40 Protection of Environment 30 2010-07-01 2010-07-01 false Quaternary ammonium compounds, dicoco alkyldimethyl, chlorides, reaction products with silica. 721.10154 Section 721.10154 Protection of Environment... SUBSTANCES Significant New Uses for Specific Chemical Substances § 721.10154 Quaternary ammonium...

  20. Effect of quaternary ammonium salts on flotation behavior of aluminosilicate minerals

    Institute of Scientific and Technical Information of China (English)

    ZHAO Sheng-gui; ZHONG Hong; LIU Guang-yi

    2007-01-01

    The electrokinetic properties and flotation of diaspore, kaolinite, pyrophyllite and illite with quaternary ammonium salts collectors were studied. The results of flotation tests show that the collecting ability of quaternary ammonium salts for the four minerals is in the order(from strong to weak) of octadecyl dimethyl benzyl ammonium chloride(ODBA), cetyl trimethyl ammonium bromide(CTAB), dodecyl trimethyl ammonium chloride(DTAC). Under the condition of alkalescence, it is possible to separate the diaspore from the silicate minerals such as kaolinite, illite and pyrophyllite using quaternary ammonium salts as collector. Isoelectric points (IEP) of diaspore, kaolinite, pyrophyllite and illite are pH=6.0, 3.4, 2.3 and 3.2, respectively. Quaternary ammonium salts can change ζ-potential of the aluminosilicate minerals obviously. The flotation mechanisms were explained by ζ-potential and Fourier transform infrared spectrum (FT-IR) measurements. The results demonstrate that only electrostatic interaction takes place between aluminosilicate minerals (diaspore, kaolinite, pyrophyllite and illite) and quaternary ammonium salts.

  1. Ammonium-oxidizing bacteria facilitate aerobic degradation of sulfanilic acid in activated sludge.

    Science.gov (United States)

    Chen, Gang; Ginige, Maneesha P; Kaksonen, Anna H; Cheng, Ka Yu

    2014-01-01

    Sulfanilic acid (SA) is a toxic sulfonated aromatic amine commonly found in anaerobically treated azo dye contaminated effluents. Aerobic acclimatization of SA-degrading mixed microbial culture could lead to co-enrichment of ammonium-oxidizing bacteria (AOB) because of the concomitant release of ammonium from SA oxidation. To what extent the co-enriched AOB would affect SA oxidation at various ammonium concentrations was unclear. Here, a series of batch kinetic experiments were conducted to evaluate the effect of AOB on aerobic SA degradation in an acclimatized activated sludge culture capable of oxidizing SA and ammonium simultaneously. To account for the effect of AOB on SA degradation, allylthiourea was used to inhibit AOB activity in the culture. The results indicated that specific SA degradation rate of the mixed culture was negatively correlated with the initial ammonium concentration (0-93 mM, R²= 0.99). The presence of AOB accelerated SA degradation by reducing the inhibitory effect of ammonium (≥ 10 mM). The Haldane substrate inhibition model was used to correlate substrate concentration (SA and ammonium) and oxygen uptake rate. This study revealed, for the first time, that AOB could facilitate SA degradation at high concentration of ammonium (≥ 10 mM) in an enriched activated sludge culture.

  2. On the influence of thiamine and ammonium ions on alcoholic fermentation

    NARCIS (Netherlands)

    Maesen, Th.J.M.

    1953-01-01

    1. 1. In a glucose-sodium acetate medium of pH 5.6 the fermentation rate of bakers' yeast remains constant at a low level during several hours, while in the presence of ammonium sulphate it gradually increases. The rise is steeper in the presence of thiamine. 2. 2. After the ammonium ions have been

  3. The effect of the ammonium ion on activated-sludge settling properties

    DEFF Research Database (Denmark)

    Novak, John Thomas

    2001-01-01

    by addition of sodium or ammonium, the interfacial settling velocity decreased, although the greatest drop was in the reactor containing ammonium. When addition of the nitrification inhibitor was stopped, rapid recovery of nitrification occurred but the settling properties improved more slowly. It seemed...

  4. Nitrogen phosphoric fertilizer production technology on the base of Central Kyzylkum phosphorites and ammonium nitrate melt

    Directory of Open Access Journals (Sweden)

    Shavkat Namazov

    2012-11-01

    Full Text Available The process of obtaining nitrogen phosphoric fertilizer by introduction Central Kyzylkum phosphates and ammonium nitrate melt is studied. On the base of these results production technology diagram for nitrogen phosphoric fertilizer is offered. The given technology was approved and developed at the functioning devices of OJSC “NAVOIAZOT” ammonium nitrate shop.

  5. 75 FR 56489 - Separation Distances of Ammonium Nitrate and Blasting Agents From Explosives or Blasting Agents...

    Science.gov (United States)

    2010-09-16

    ... Ammonium Nitrate and Blasting Agents From Explosives or Blasting Agents (2002R-226P) AGENCY: Bureau of... CFR 555.220 set forth a table of separation distances of ammonium nitrate and blasting agents from explosives or blasting agents followed by six explanatory notes. Note three (3) states that the...

  6. Sulfuric acid-ammonium sulfate aerosol: optical detection in the St. Louis region.

    Science.gov (United States)

    Charlson, R J; Vanderpol, A H; Covert, D S; Waggnoner, A P; Ahlquist, N C

    1974-04-12

    Nephelometric sensing of the deliquescence of ammonium sulfate produced by the reaction of sulfuric acid or ammonium bisulfate aerosol with ammonia provides a means for detecting these substances in air. Field experiments show them to be the dominant substances in the submicrometer, light-scattering aerosol in the St. Louis region.

  7. 75 FR 41725 - Food Additives Permitted in Feed and Drinking Water of Animals; Ammonium Formate

    Science.gov (United States)

    2010-07-19

    ... Additives Permitted in Feed and Drinking Water of Animals; Ammonium Formate AGENCY: Food and Drug... regulations for food additives permitted in feed and drinking water of animals to provide for the safe use of ammonium formate as an acidifying agent in swine feed. This action is in response to a food...

  8. Alkali metal and ammonium chlorides in water and heavy water (binary systems)

    CERN Document Server

    Cohen-Adad, R

    1991-01-01

    This volume surveys the data available in the literature for solid-fluid solubility equilibria plus selected solid-liquid-vapour equilibria, for binary systems containing alkali and ammonium chlorides in water or heavy water. Solubilities covered are lithium chloride, sodium chloride, potassium chloride, rubidium chloride, caesium chloride and ammonium chloride in water and heavy water.

  9. Suppression of interference in the AAS determination of chromium by use of ammonium bifluoride.

    Science.gov (United States)

    Purushottam, A; Naidu, P P; Lal, S S

    1973-07-01

    Addition of 1% of ammonium bifluoride successfully suppresses interference by diverse ions in the atomic-absorption determination of chromium(VI). If the sample solutions also contain chromium(III) addition of 1% of ammonium bifluoride and 0.2% of sodium sulphate is recommended for the suppression.

  10. Irritant contact dermatitis due to ammonium bifluoride in two infant twins.

    Science.gov (United States)

    Toledo, Fernando; Silvestre, Juan Francisco; Cuesta, Laura; Bañuls, José

    2013-01-01

    Ammonium bifluoride is one of the most corrosive acids that may produce severe chemical burns when in contact with skin. This hazardous chemical is widely used in household products. We report two pediatric cases of irritant contact dermatitis after exposure to a rust remover, which contained ammonium bifluoride.

  11. Nitrogen removal by autotrophic ammonium oxidizing bacteria enrichment under anaerobic conditions

    Directory of Open Access Journals (Sweden)

    Pongsak (Lek Noophan

    2008-07-01

    Full Text Available Sludge from an anoxic tank at the centralized wastewater treatment plant, Nong Khaem, Bangkok, Thailand, was inoculatedin an anaerobic sequencing batch reactor (ASBR. The optimal compositions and operating conditions of the stock of autotrophic ammonium oxidizing bacteria medium were determined. The process of oxidizing ammonium with bacteria under anaerobic conditions is often referred to as the Anammox process (NO2- to N2 gas, using NH4+ as the electron donor and NO2- as the electron acceptor. The startup period for the anammox culture took more than three months. With ammoniumand nitrite concentration ratios of 1:1.38 and 1:1.6, the nitrogen conversion rate zero order. Fluorescent in situ hybridization(FISH was used to identify specific autotrophic ammonium oxidizing bacteria (Nitrosomonas spp., Candidatus Brocadia anammoxidans, and Candidatus Kuenenia stuttgartiensis. Results from this work demonstrated a shift in the species of ammonium oxidizing bacteria from Nitrosomonas spp. to Candidati Brocadia anammoxidans and Kuenenia stuttgartiensis, with increased ammonium concentrations from 3 mM to 15 mM. Under NH4+:NO2- ratios of 1:1.38 and 1:1.6 the ammoniumoxidizing bacteria were able to remove both ammonium and nitrite simultaneously. The specific nitrogen removal rate of theanammox bacteria (Candidati Brocadia anammoxidans and Kuenenia stuttgartiensis was significantly higher than that of anaerobic ammonium oxidizing bacteria (Nitrosomonas spp.. Anaerobic ammonium oxidizing bacteria (Candidati Brocadia anammoxidans and Kuenenia stuttgartiensis are strict anaerobes.

  12. Ammonium across a Selective Polymer Inclusion Membrane : Characterization, Transport, and Selectivity

    NARCIS (Netherlands)

    Casadella, Anna; Schaetzle, Olivier; Loos, Katja

    2016-01-01

    The recovery of ammonium from urine requires distinguishing and excluding sodium and potassium. A polymer inclusion membrane selective for ammonium is developed using an ionophore based on pyrazole substituted benzene. The interactions of the components are studied, as well as their effect on transp

  13. Mineral carbonation of phosphogypsum waste for production of useful carbonate and sulfate salts

    Directory of Open Access Journals (Sweden)

    Hannu-Petteri eMattila

    2015-11-01

    Full Text Available Phosphogypsum (CaSO4·2H2O waste is produced in large amounts during phosphoric acid (H3PO4 production. Minor quantities are utilized in construction or agriculture, while most of the material is stockpiled, creating an environmental challenge to prevent pollution of natural waters. In principle, the gypsum waste could be used to capture several hundred Mt of carbon dioxide (CO2. For example, when gypsum is converted to ammonium sulfate ((NH42SO4 with ammonia (NH3 and CO2, also solid calcium carbonate (CaCO3 is generated. The ammonium sulfate can be utilized as a fertilizer or in other mineral carbonation processes that use magnesium silicate-based rock as feedstock, while calcium carbonate has various uses as e.g. filler material. The reaction extent of the described process was studied by thermodynamic modeling and experimentally as a function of reactant concentrations and temperature. Other essential properties such as purity and quality of the solid products are also followed. Conversion efficiencies of >95% calcium from phosphogypsum to calcium carbonate are obtained. Scalenohedral, rhombohedral and prismatic calcite particles can be produced, though the precipitates contain certain contaminants such as rare earth metals and sulfur from the gypsum. A reverse osmosis membrane cartridge is also tested as an alternative and energy-efficient method of concentrating the ammonium sulfate salt solution instead of the traditional evaporation of the process solution.

  14. Liquid-liquid extraction kinetics of uranyl nitrate and actinides (III)-lanthanides nitrates by extractants with amide function; Cinetique d`extraction liquide-liquide du nitrate d`uranyle et des nitrates d`actinides (III) et de lanthanides (III) par des extractants a fonction amide

    Energy Technology Data Exchange (ETDEWEB)

    Toulemonde, V.

    1995-12-20

    Nowadays, the most important part of electric power is generated by fission energy. But spent fuels have then to be reprocessed. The production of these reprocessed materials separately and with a high purity level is done according to a liquid-liquid extraction process (Purex process) with the use of tributyl phosphate as solvent. Optimization studies concerning the extracting agent have been undertaken. This work gives the results obtained for the uranyl nitrate and the actinides (III)-lanthanides (III) nitrates extraction by extractants with amide function (monoamide for U(VI) and diamide for actinides (III) and lanthanides (III)). The extraction kinetics have been studied in the case of a metallic specie transfer from the aqueous phase towards the organic phase. The experiments show that the nitrates extraction kinetics is limited by the complexation chemical reaction of the species at the interface between the two liquids. An adsorption-desorption interfacial reactional mechanism (Langmuir theory) is proposed for the uranyl nitrate. (O.M.). 89 refs.

  15. Interactions between nitrate and ammonium in their uptake, allocation, assimilation, and signaling in plants.

    Science.gov (United States)

    Hachiya, Takushi; Sakakibara, Hitoshi

    2016-12-21

    Nitrogen (N) availability is a major factor determining plant growth and productivity. Plants acquire inorganic N from the soil, mainly in the form of nitrate and ammonium. To date, researchers have focused on these N sources, and demonstrated that plants exhibit elaborate responses at both physiological and morphological levels. Mixtures of nitrate and ammonium are beneficial in terms of plant growth, as compared to nitrate or ammonium alone, and therefore synergistic responses to both N sources are predicted at different steps ranging from acquisition to assimilation. In this review, we summarize interactions between nitrate and ammonium with respect to uptake, allocation, assimilation, and signaling. Given that cultivated land often contains both nitrate and ammonium, a better understanding of the synergism between these N sources should help to identify targets with the potential to improve crop productivity.

  16. Kinetics Analysis on Mixing Calcination Process of Fly Ash and Ammonium Sulfate

    Institute of Scientific and Technical Information of China (English)

    Peng Wang; Laishi Li; Dezhou Wei

    2014-01-01

    abstract The further development of the extraction of alumina that is produced in the calcination process of ammonium sulfate mixed with fly ash was limited because of the lack of systematic theoretical study. In order to aggrandize the research of the calcination process, the kinetics and reaction mechanism of the calcinations were studied. The result suggests that there are two stages in the calcination process, and the alumina extraction rate increases swiftly in the initial stage, but slows down increasing in the later stage. The apparent activation energy of the initial and later stages equals to 13.31 and 35.65 kJ·mol-1, respectively. In the initial stage, ammonium sulfate reacts directly with mullite in the fly ash to form ammonium aluminum sulfate, while in the later stage, alumi-num sulfate is formed by the reaction between ammonium aluminum sulfate and ammonium sulfate.

  17. Start-up of a biofilm airlift system to obtain partial nitrification of a high-strength ammonium wastewater

    Energy Technology Data Exchange (ETDEWEB)

    Bartoli, A.; Perez, J.; Lafuente, J.; Carrera, J.

    2009-07-01

    In order to fulfil the new legal requirements with regards to the sewage sludge produced in the WWTPs an on-going EU research project is devoted to the reduction. Modification and valorisation of sludge (REMOVALS, n 018525, www.etseq.urv.es/removals/). Among many other initiatives inside this project, a possible valorisation of sluge is the production of activated carbon (AC) which could be use, among other applications, as carrier for biofilm development. One of the possible applications of biofilm reactors in the current process diagram of a WWTP is the specific treatment of a high-strength ammonium wastewater produced in the anaerobic digestion of the sludge, the so-called reject water. (Author)

  18. Ceric Ammonium Nitrate-Mediated Oxidative Cycloaddition of 1,3-Dicarbonyls to β-Aryl-α, β-unsaturated Ketones

    Institute of Scientific and Technical Information of China (English)

    ZHANG Wei; HUO Cong-De; LIU Zheng-Gang; LIU Zhong-Li

    2003-01-01

    @@ Oxidative addition of carbon-centred radicals to alkenes mediated by metal salts ( MnⅢ, CeⅣ, HgⅡ,PdⅣ, AgⅠ,and CuⅡ) has received considerable attention over last decade in organic synthesis for construction of carbon-carbon bond. [1,2] Among them, manganese(Ⅲ) acetate and ceric(Ⅳ) ammonium nitrate (CAN) have been use most efficiently. Recently, CAN-mediated oxidative cycloaddition of 1,3-dicarbonyl compounds to alkenes, conjugated compounds, enol silyl ethers and alkynes, has been studied extensively. We exploited that the CAN-mediated oxidative cycloaddition of 1,3-dicarbonyl compounds to β-aryl-α,β-unsaturated ketones afforded dihydrofuran derivatives in moderate yields. All the products were characterized by 1H NMR, 13C NMR, MS and HRMS spectra.

  19. Anaerobic ammonium oxidation in traditional municipal wastewater treatment plants with low-strength ammonium loading: Widespread but overlooked.

    Science.gov (United States)

    Wang, Shanyun; Peng, Yongzhen; Ma, Bin; Wang, Shuying; Zhu, Guibing

    2015-11-01

    Occurrence of anaerobic ammonium oxidation (anammox) in marine and freshwater systems has greatly changed our understanding of global nitrogen (N) cycle and promoted the investigation of the role and ecological features of anammox in anthropogenic ecosystems. This study focused on the spatio-temporal abundance, activity, and biodiversity of anammox bacteria in full-scale municipal wastewater treatment plants (WWTPs) via traditional nitrification/denitrification route with low-strength ammonium loading. The anammox bacteria were detected in all the treatment units at the five WWTPs tested, even in aerobic zones (dissolved oxygen >2 mg L(-1)) with abundance of 10(5)-10(7) hydrazine synthase (hzs) gene copies g(-1). The (15)N-isotope tracing technology revealed that the anammox rates in WWTPs ranged from 0.08 to 0.36 μmol N g(-1) h(-1) in winter and 0.12-1.20 μmol N g(-1) h(-1) in summer with contributions of 2.05-6.86% and 1.71-7.26% to N2 production, respectively. The diversity of anammox bacteria in WWTPs was distributed over only two genera, Brocadia and Kuenenia. Additionally, the exploration of potential interspecies relationships indicated that ammonia oxidation bacteria (AOB) was the major nitrite-substrate producer for anammox during nitrification, while Nitrospira, a nitrite oxidation bacteria (NOB), was the potential major competitor for nitrite. These results suggested the contribution of N-removal by the widespread of anammox has been overlooked in traditional municipal WWTPs, and the ecological habitats of anammox bacteria in anthropogenic ecosystems are much more abundant than previously assumed.

  20. Fabrication of ammonium perchlorate/copper-chromium oxides core-shell nanocomposites for catalytic thermal decomposition of ammonium perchlorate

    Energy Technology Data Exchange (ETDEWEB)

    Eslami, Abbas, E-mail: eslami@umz.ac.ir [Department of Inorganic Chemistry, Faculty of Chemistry, University of Mazandaran, P.O.Box 47416-95447, Babolsar (Iran, Islamic Republic of); Juibari, Nafise Modanlou [Department of Inorganic Chemistry, Faculty of Chemistry, University of Mazandaran, P.O.Box 47416-95447, Babolsar (Iran, Islamic Republic of); Hosseini, Seyed Ghorban [Department of Chemistry, Malek Ashtar University of Technology, P.O. Box 16765-3454, Tehran (Iran, Islamic Republic of)

    2016-09-15

    The ammonium perchlorate/Cu(II)-Cr(III)-oxides(AP/Cu-Cr-O) core-shell nanocomposites were in-situ prepared by deposition of copper and chromium oxides on suspended ammonium perchlorate particles in ethyl acetate as solvent. The results of differential scanning calorimetery (DSC) and thermal gravimetric analysis (TGA) experiments showed that the nanocomposites have excellent catalytic effect on the thermal decomposition of AP, so that the released heat increases up to about 3-fold over initial values, changing from 450 J/g for pure AP to 1510 J/g for most appropriate mixture. For better comparison, single metal oxide/AP core-shell nanocomposite have also been prepared and the results showed that they have less catalytic effect respect to mixed metal oxides system. Scanning electron microscopy (SEM) results revealed homogenous deposition of nanoparticles on the surface of AP and fabrication of core-shell structures. The kinetic parameters of thermal decomposition of both pure AP and AP/Cu-Cr-O samples have been calculated by Kissinger method and the results showed that the values of pre-exponential factor and activation energy are higher for AP/Cu-Cr-O nanocomposite. The better catalytic effect of Cu-Cr-O nanocomposites is probably attributed to the synergistic effect between Cu{sup 2+} and Cr{sup 3+} in the nanocomposites, smaller particle size and more crystal defect. - Highlights: • The Cu-Cr-O nanoparticles were synthesized by chemical liquid deposition method. • Then, the AP/Cu-Cr-O core-shell nanocomposites were prepared. • The core-shell samples showed high catalytic activity for AP decomposition. • Thermal decomposition of samples occurs at lower temperature range.

  1. 75 FR 3668 - Conditional Approval and Promulgation of State Implementation Plans; Ohio; Carbon Monoxide and...

    Science.gov (United States)

    2010-01-22

    ... your e-mail address will be automatically captured and included as part of the comment that is placed...; metallic carbonates; ammonium carbonate; methane (except methane from landfill gases); and ethane. This... miscellaneous metal and plastic parts coatings document in September, 2008. This limit is less stringent...

  2. Effect of carbon dioxide and ammonium removal on pH changes in polishing ponds

    NARCIS (Netherlands)

    Cavalcanti, P.F.F.; Haandel, van A.; Lettinga, G.

    2002-01-01

    If nutrient removal is to be obtained in ponds treating sewage, the pH must be raised so that ammonia can desorb and phosphates can precipitate. In this paper it is shown that the pH increase in ponds can be predicted quantitatively from simple stoichiometry, taking into consideration physical and b

  3. A novel method for preparation of hollow and solid carbon spheres

    Indian Academy of Sciences (India)

    Boyang Liu; Dechang Jia; Jiancun Rao; Qiangchang Meng; Yingfeng Shao

    2008-10-01

    Hollow and solid carbon spheres were prepared by the reaction of ferrocene and ammonium carbonate in a sealed quartz tube at 500°C. The morphology and microstructure of the product were characterized by X-ray diffraction, Raman spectroscopy, scanning electron microscopy and transmission electron microscopy. The carbon spheres are amorphous and their diameters range from 0.8–2.8 m. The shell thickness of the hollow carbon spheres is not uniform and ranges from 100–180 nm. It is suggested that ammonium carbonate is crucial for the formation of carbon spheres and its amount also influences the morphology of the product. The method may be suitable for large scale preparation of carbon spheres.

  4. Relating dynamic conditions to the performance of biological rapid sand filters used to remove ammonium, iron, and manganese from drinking water

    DEFF Research Database (Denmark)

    Lee, Carson; Albrechtsen, Hans-Jørgen; Smets, Barth F.;

    and media samples were collected throughout the depth of the column and over the operational cycle of the columns. Substrate analysis included ammonium, nitrite, nitrate, iron, and manganese. Qpcr analysis were also performed to quantify ammonium oxidizing bacteria (AOBs), ammonium oxidizing archea ( AOAs...... on the roles of both Ammonium oxidizing bacteria (AOBs) and Ammonium oxidizing archea (AOAs) in the biological removal of ammonium in rapid sand filters and how varying substrate loadings and operating conditions can affect the biological performance of these filters....

  5. 21 CFR 878.4015 - Wound dressing with poly (diallyl dimethyl ammonium chloride) (pDADMAC) additive.

    Science.gov (United States)

    2010-04-01

    ... ammonium chloride) (pDADMAC) additive. 878.4015 Section 878.4015 Food and Drugs FOOD AND DRUG... DEVICES Surgical Devices § 878.4015 Wound dressing with poly (diallyl dimethyl ammonium chloride) (pDADMAC... Dressing With Poly (Diallyl Dimethyl Ammonium Chloride) (pDADMAC) Additive.” See § 878.1(e)...

  6. 76 FR 34749 - Ammonium Nitrate From Russia; Scheduling of an expedited five-year review concerning the...

    Science.gov (United States)

    2011-06-14

    ... COMMISSION Ammonium Nitrate From Russia; Scheduling of an expedited five- year review concerning the antidumping duty order on ammonium nitrate From Russia AGENCY: United States International Trade Commission... whether revocation of the antidumping duty order on ammonium nitrate from Russia would be likely to...

  7. 77 FR 73674 - Ammonium Nitrate From Ukraine; Notice of Revised Schedule of the Five-year Review Concerning the...

    Science.gov (United States)

    2012-12-11

    ...)] Ammonium Nitrate From Ukraine; Notice of Revised Schedule of the Five-year Review Concerning the Antidumping Duty Order on Ammonium Nitrate From Ukraine AGENCY: United States International Trade Commission... established a schedule for the conduct of the 5-year review of Ammonium Nitrate from Ukraine (77 FR...

  8. 40 CFR 721.6540 - Acrylamide, polymers with tetraalkyl ammonium salt and polyalkyl, aminoalkyl meth-a-cryl-a-mide...

    Science.gov (United States)

    2010-07-01

    ... ammonium salt and polyalkyl, aminoalkyl meth-a-cryl-a-mide salt. 721.6540 Section 721.6540 Protection of... with tetraalkyl ammonium salt and polyalkyl, aminoalkyl meth-a-cryl-a-mide salt. (a) Chemical... as acrylamide, polymers with tetraalkyl ammonium salt and poly-al-kyl, amino alkyl...

  9. Upgrading fertilizer production wastewater effluent quality for ammonium discharges through ion exchange with clinoptilolite.

    Science.gov (United States)

    Beler-Baykal, B; Allar, A D

    2008-06-01

    It had previously been shown that ammonium selective natural zeolite clinoptilolite may be used successfully as an ion exchanger for ammonium removal and nitrogen control from domestic wastewater. The process had been reported to be acceptable either by itself alone or as an upgrade. In this work, the possibility of using clinoptilolite for ammonium removal from fertilizer production wastewater was investigated. The fertilizer plant under consideration was rather a non-typical one with a lower ammonium strength than what is normally expected, and a variable effluent concentration. Batch experiments were performed to assess the capacity of clinoptilolite towards ammonium removal from an industrial wastewater at two different pHs. Flow experiments for the characterization of system behavior under continuous feeding conditions at different contact times were conducted for breakthrough analysis. Both real and simulated fertilizer wastewater samples were investigated and the results have shown that the real one may successfully be represented by the simulated one. Experimental results have shown that surface capacities exceeding 14 mg ammonium g(-1) clinoptilolite could be attained, complete removal of ammonium may be achieved with empty bed contact times of 10 min or higher and ion exchange with clinoptilolite could be used successfully to comply with the effluent standards given for the fertilizer plant.

  10. Coastal water column ammonium and nitrite oxidation are decoupled in summer

    Science.gov (United States)

    Heiss, Elise M.; Fulweiler, Robinson W.

    2016-09-01

    Water column nitrification is a key process in the nitrogen cycle as it links reduced and oxidized forms of nitrogen and also provides the substrate (nitrate) needed for reactive nitrogen removal by denitrification. We measured potential water column ammonium and nitrite oxidation rates at four sites along an estuary to continental shelf gradient over two summers. In most cases, nitrite oxidation rates outpaced ammonium oxidation rates. Overall, ammonium and nitrite oxidation rates were higher outside of the estuary, and this trend was primarily driven by higher oxidation rates in deeper waters. Additionally, both ammonium and nitrite oxidation rates were impacted by different in situ variables. Ammonium oxidation rates throughout the water column as a whole were most positively correlated to depth and salinity and negatively correlated to dissolved oxygen and light. In contrast, nitrite oxidation rates throughout the water column were negatively correlated with light and pH. Multivariate regression analysis revealed that while both surface (20 m) ammonium oxidation rates were most strongly predicted by depth and light, surface rates were also regulated by salinity and deep rates by temperature. Surface (20 m) nitrite oxidation rates. These results support the growing body of evidence that ammonium oxidation and nitrite oxidation are not always coupled, should be measured separately, and are influenced by different environmental conditions.

  11. Preparation and characteristic research of anhydrous magnesium chloride with dehydrated ammonium carnallite

    Institute of Scientific and Technical Information of China (English)

    ZHOU Ning-bo; CHEN Bai-zhen; HE Xin-kuai; LI Yi-bing

    2006-01-01

    Taking the saline lake bischofite and NH4Cl that was removed with the ammonia method and continuwas synthesized. And then the ammonium carnallite was dehydrated to some extent at 160℃ for 4 h. Ammonium carnallite reacted with ammonia at 240℃ for 150 min and the ammonation ammonium carnallite was produced. Finally, the ammonation ammonium carnallite was calcined at 750℃ into anhydrous magnesium chloride containing only 0.1% (mass fraction) of MgO. On the other hand, dehydrated ammonium carnallite was mixed with the solid ammonium chloride at mass ratio 1:4 at high temperature and with the differential pressure of HN3 above 30.5 kPa. The dehydrated ammonium carnallite of mixture was dehydrated at 410℃, and then calcined at 700℃ into anhydrous magnesium chloride with only 0. 087% (mass fraction) of MgO. X-ray diffraction and electron microscopy analysis results prove that anhydrous magnesium chloride obtained by both methods hasn't mixed phases, the particle is large and even has good dispersion, which is suitable for preparation of metal magnesium in the electrolysis.

  12. Ammonium and potassium removal from swine liquid manure using clinoptilolite, chabazite and faujasite zeolites.

    Science.gov (United States)

    Montégut, Gaëtan; Michelin, Laure; Brendlé, Jocelyne; Lebeau, Bénédicte; Patarin, Joël

    2016-02-01

    This study concerns cationic exchanges performed in order to remove ammonium and potassium cations from manure by using various zeolites: clinoptilolite, chabazite and NaX faujasite. First, the effect of temperature (25 °C and 40 °C) on the exchange rate between zeolites and an ammonium chloride solution was investigated. Then, cationic exchanges were performed on these three zeolites using on one side a mixed ammonium and potassium chloride solution reproducing the chemical composition of a swine manure and on the other side the corresponding liquid manure. No significant difference was observed on the exchange rate and the trapping of ammonium cations by changing the temperature (25 or 40 °C). Clinoptilolite showed a good selectivity towards ammonium cations using model (NH4Cl, and mixed NH4Cl/KCl) solutions but is less efficient with the liquid manure. Chabazite and faujasite were found more efficient than clinoptilolite for trapping ammonium cations. However, NaX faujasite enables trapping 3 times more ammonium cations than chabazite from manure (60 and 20 mg/g, respectively). Moreover, chabazite allowed to trap the same amount of potassium cations than NaX faujasite (33 and 35 mg/g, respectively).

  13. Paleosols in central Illinois as potential sources of ammonium in groundwater

    Science.gov (United States)

    Glessner, J.J.G.; Roy, W.R.

    2009-01-01

    Glacially buried paleosols of pre-Holocene age were evaluated as potential sources for anomalously large concentrations of ammonium in groundwater in East Central Illinois. Ammonium has been detected at concentrations that are problematic to water treatment facilities (greater than 2.0 mg/L) in this region. Paleosols characterized for this study were of Quaternary age, specifically Robein Silt samples. Paleosol samples displayed significant capacity to both store and release ammonium through experiments measuring processes of sorption, ion exchange, and weathering. Bacteria and fungi within paleosols may significantly facilitate the leaching of ammonium into groundwater by the processes of assimilation and mineralization. Bacterial genetic material (DNA) was successfully extracted from the Robein Silt, purified, and amplified by polymerase chain reaction to produce 16S rRNA terminal restriction fragment length polymorphism (TRFLP) community analyses. The Robein Silt was found to have established diverse and viable bacterial communities. 16S rRNA TRFLP comparisons to well-known bacterial species yielded possible matches with facultative chemolithotrophs, cellulose consumers, nitrate reducers, and actinomycetes. It was concluded that the Robein Silt is both a source and reservoir for groundwater ammonium. Therefore, the occurrence of relatively large concentrations of ammonium in groundwater monitoring data may not necessarily be an indication of only anthropogenic contamination. The results of this study, however, need to be placed in a hydrological context to better understand whether paleosols can be a significant source of ammonium to drinking water supplies. ?? 2009 National Ground Water Association.

  14. Effects of High Ammonium Concentration on Growth and Nutrient Uptake of Lettuce Plants with Solution Culture

    Institute of Scientific and Technical Information of China (English)

    2005-01-01

    A nutrition solution experiment was conducted over two months to investigate the response of vegetable crops to high concentrations of ammonium, using lettuce (Lactuca sativa L. cv. Angustana Irish) as a test crop. Ammonium concentrations were designed in 5 levels, ranging from 12 mmol N L-1 to 22 mmol N L-1 and local tap water was used as water source. At the first culture stage (0-9 days), lettuce plants maintained normal growth while the lettuce roots were increasingly impaired. During the subsequent three stages the root structure was greatly damaged, and roots became brown or black through continuous supply of high concentration of ammonium. However, there was no obvious reduction of the aboveground biomass of the plants in the high ammonium treatments compared to those supplied with nitrate alone. In contrast to results obtained in another experiment from us with distilled water, the detrimental effect of high ammonium concentration on lettuce growth was greatly alleviated. Based on the results, it was postulated that the small amount of nitrate and the higher amount of bicarbonate existed in the tap water might mitigate the adverse effects of high ammonium N. The higher bicarbonate content in water and soil has usually been regarded as a major constraint factor limiting plant growth in calcareous soil areas. However, the reaction of bicarbonate to ammonium might produce positively interactive effect on reduction of both damages. The lettuce plants grown in ammonium solutions took up less P, K, Fe, Mn and Cu and more Ca than those grown in the nitrate nutrient solution. In conclusion, the results indicated that the N form imposed an obvious influence on absorption of cations and anions. Supplying ammonium-N stimulated transport of Ca, Mg and Mn to shoots of lettuce.

  15. Monthly variations in nitrogen isotopes of ammonium and nitrate in wet deposition at Guangzhou, south China

    Science.gov (United States)

    Jia, Guodong; Chen, Fajin

    2010-06-01

    Monthly nitrogen isotopes of ammonium and nitrate in wet deposition in the city of Guangzhou, and the causes of their variability, are reported in this paper. Nitrate δ 15N showed nearly constant values around zero in the dry season (October to April), but oscillating values from negative to positive in the rainy season (May to September). By contrast, ammonium δ 15N displayed lower values during the rainy season than in the dry season. The rural area north of the city was considered as the prominent source of ammonium and nitrate in spring and early summer (May and June), as suggested by their concurrent negative isotopic trends and higher NH 4+/NO 3- ratios. From July to September, different dominating sources from the city, i.e., fossil fuel combustion for nitrate, and sewage and waste emission for ammonium, caused disparate δ 15N trends of the two species, showing positive nitrate δ 15N, but still negative ammonium δ 15N. During the cool dry season, the high values of ammonium δ 15N and concurrently low NH 4+/NO 3- ratios suggested the decrease in NH 3 volatilization and relatively important thermogenic origin of ammonium, but the intermediate nitrate δ 15N values around zero may be a result of a balanced emission of NO x from the city and the rural areas. The isotopic effects of chemical conversion of NO x to nitrate and washout of nitrate were ruled out as significant causes of nitrate δ 15N variability, but ammonium washout, during which 15N is assumed to be preferentially removed, may partly contribute to the ammonium δ 15N variability.

  16. Natural attenuation potential of tricholoroethene in wetland plant roots: role of native ammonium-oxidizing microorganisms.

    Science.gov (United States)

    Qin, Ke; Struckhoff, Garrett C; Agrawal, Abinash; Shelley, Michael L; Dong, Hailiang

    2015-01-01

    Bench-scale microcosms with wetland plant roots were investigated to characterize the microbial contributions to contaminant degradation of trichloroethene (TCE) with ammonium. The batch system microcosms consisted of a known mass of wetland plant roots in aerobic growth media where the roots provided both an inoculum of root-associated ammonium-oxidizing microorganisms and a microbial habitat. Aqueous growth media, ammonium, and TCE were replaced weekly in batch microcosms while retaining roots and root-associated biomass. Molecular biology results indicated that ammonium-oxidizing bacteria (AOB) were enriched from wetland plant roots while analysis of contaminant and oxygen concentrations showed that those microorganisms can degrade TCE by aerobic cometabolism. Cometabolism of TCE, at 29 and 46 μg L(-1), was sustainable over the course of 9 weeks, with 20-30 mg L(-1) ammonium-N. However, at 69 μg L(-1) of TCE, ammonium oxidation and TCE cometabolism were completely deactivated in two weeks. This indicated that between 46 and 69 μg L(-1) TCE with 30 mg L(-1) ammonium-N there is a threshold [TCE] below which sustainable cometabolism can be maintained with ammonium as the primary substrate. However, cometabolism-induced microbial deactivation of ammonium oxidation and TCE degradation at 69 μg L(-1) TCE did not result in a lower abundance of the amoA gene in the microcosms, suggesting that the capacity to recover from TCE inhibition was still intact, given time and removal of stress. Our study indicates that microorganisms associated with wetland plant roots can assist in the natural attenuation of TCE in contaminated aquatic environments, such as urban or treatment wetlands, and wetlands impacted by industrial solvents.

  17. Thermochemical Properties and Decomposition Kinetics of Ammonium Magnesium Phosphate Monohydrate

    Institute of Scientific and Technical Information of China (English)

    WU,Jian; YUAN,Ai-Qun; HUANG,Zai-Yin; TONG,Zhang-Fa; CHEN,Jie; LIANG,Rong-Lan

    2007-01-01

    Ammonium magnesium phosphate monohydrate NH4MgPO4·H2O was prepared via solid state reaction at room temperature and characterized by XRD, FT-IR and SEM. Thermochemical study was performed by an isoperibol solution calorimeter, non-isothermal measurement was used in a multivariate non-linear regression analysis to determine the kinetic reaction parameters. The results show that the molar enthalpy of reaction above is (28.795±0.182) kJ/mol (298.15 K), and the standard molar enthalpy of formation of the title complex is (-2185.43±13.80)kJ/mol (298.15 K). Kinetics analysis shows that the second decomposition of NH4MgPO4·H2O acts as a double-step reaction: an nth-order reaction (Fn) with n=4.28, E1=147.35 kJ/mol, A1=3.63×1013 s-1 is followed by a second-order reaction (F2) with E2=212.71 kJ/mol, A2= 1.82×1018 s-1.

  18. Synthesis and characterization of ammonium phosphate fertilizers with boron

    Directory of Open Access Journals (Sweden)

    ANGELA MAGDA

    2010-07-01

    Full Text Available The concentration of boron, an essential micronutrient for plants, presents a narrow range between deficiency and toxicity. In order to provide the boron requirement for plants, and to avoid toxicity problems, boron compounds are mixed with basic fertilizers. Sodium borate pentahydrate was used as a boron source. Ammonium orthophosphates fertilizers with boron were prepared by neutralizing phosphoric acid with ammonia and addition of variable amounts of sodium tetraborate pentahydrate to the reaction mixture at a NH3:H3PO4 molar ratio of 1.5. The fertilizers obtained with boron contents ranging from 0.05 to 1 % (w/w were fully characterized by chemical analysis, thermal analysis, X-ray diffraction and infrared spectrophotometry. The studies showed that up to 500 °C, regardless of the boron content, no significant changes concerning thermal stability and nutritional properties occurred. Above 500 °C, an increase of thermal stability with an increase of the boron content was observed. X-Ray diffraction of a heat-treated sample containing 5 % (w/w boron indicated the appearance of boron orthophosphate, BPO4, as a new crystalline phase, and the disappearance of the previous structures above 500 °C, which explains the increase in thermal stability.

  19. Crystallization of Chicken Egg-White Lysozyme from Ammonium Sulfate

    Science.gov (United States)

    Forsythe, Elizabeth L.; Snell, Edward H.; Pusey, Marc L.

    1997-01-01

    Chicken egg-white lysozyme was crystallized from ammonium sulfate over the pH range 4.0-7.8, with protein concentrations from 100 to 150 mg/ml. Crystals were obtained by vapor-diffusion or batch-crystallization methods. The protein crystallized in two morphologies with an apparent morphology dependence on temperature and protein concentration. In general, tetragonal crystals could be grown by lowering the protein concentration or temperature. Increasing the temperature or protein concentration resulted in the growth of orthorhombic crystals. Representative crystals of each morphology were selected for X-ray analysis. The tetragonal crystals belonged to the P4(sub 3)2(sub 1)2 space group with crystals grown at ph 4.4 having unit-cell dimensions of a = b = 78.7 1, c=38.6 A and diffracting to beyond 2.0 A. The orthorhombic crystals, grown at pH 4.8, were of space group P2(sub 1)2(sub 1)2 and had unit-cell dimensions of a = 30.51, b = 56.51 and c = 73.62 A.

  20. Interaction of ochratoxin A with quaternary ammonium beta-cyclodextrin.

    Science.gov (United States)

    Poór, Miklós; Kunsági-Máté, Sándor; Szente, Lajos; Matisz, Gergely; Secenji, Györgyi; Czibulya, Zsuzsanna; Kőszegi, Tamás

    2015-04-01

    Ochratoxin A (OTA) is a widely spread nephrotoxic food contaminant mycotoxin. Unfortunately, attenuation or prevention of the toxic effects of OTA is still an unresolved problem. Molecular inclusion of OTA by cyclodextrins (CDs) results in complexes with low stability. In the human organism, OTA exists mostly in the dianionic state (OTA(2-)). Therefore, our major goal was to develop a chemically modified cyclodextrin which gives a more stable complex with OTA than the previously published derivatives and which shows stronger preference towards OTA(2-). In our fluorescence spectroscopic study we demonstrate that quaternary ammonium beta-cyclodextrin (QABCD) fulfils both of these requirements. The calculated stability constant of the QABCD-OTA(2-) complex was 28,840 M(-1) (about 200-fold higher than that of the β-CD-OTA(2-) complex). We hypothesize, that QABCD may be a suitable tool for the decontamination of different OTA-contaminated drinks; furthermore, for alleviation of the toxic effects of OTA, such complex formation may reduce its absorption from the intestine.