WorldWideScience

Sample records for ammonium nitrates

  1. 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.

  2. Phase diagram of ammonium nitrate

    International Nuclear Information System (INIS)

    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.

  3. 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...

  4. 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

  5. 76 FR 46907 - Ammonium Nitrate Security Program

    Science.gov (United States)

    2011-08-03

    ... common example is when fertilizer-grade ammonium nitrate is mixed with fuel oil and creates an explosive... Requirements 1. Mixture Requirement 2. Threshold Weight and Individual Products Exemptions 3. Explosives... Federal Bureau of Investigation FR Federal Register HMR Hazardous Materials Regulations HMT...

  6. Development of technology for ammonium nitrate dissociation process

    International Nuclear Information System (INIS)

    Ammonia and ammonium carbonate are frequently used as reagents in fuel production and processing of liquid radioactive wastes. In particular, liquid radioactive wastes that contain ammonium nitrate are generated during operations of metal precipitation. In closed vessels at elevated temperature, for example in evaporators or deposits in tubing, ammonium nitrate may explode due to generation of gaseous nitrogen oxides [2]. In this connection, steps have to be taken to rule out conditions that result in explosion. To do that, ammonium nitrate should be removed even prior to the initial stage of its formation. This report gives results of development of a method of dissociating ammonium nitrate

  7. Hydrothermal oxidation of organic wastes using reclaimed ammonium nitrate

    Energy Technology Data Exchange (ETDEWEB)

    Proesmans, P.I.; Luan, L.; Buelow, S.J.

    1996-04-01

    Ammonium nitrate is being studied as an alternative for ammonium perchlorate as an oxidizing agent in Department of Defense 1.1 and 1.3 rocket propellants. Use of ammonium nitrate would eliminate the HCl produced by ammonium perchlorate upon thermal decomposition. To stabilize the ammonium nitrate, which suffers from phase instability, potassium dinitramide (KDN) is added. This increased use of ammonium nitrate will ultimately create a need for environmentally responsible processes to reuse ammonium nitrate extracted from demilitarized rocket motors. Ammonium Nitrate was investigated as an oxidizing agent for methanol, acetic acid and phenol. High removal of organic, ammonia and nitrate was achieved at stoichiometric concentrations. The oxidation of ammonia by nitrate was much faster than the oxidation of either methanol or acetic acid. Phenol, however, was in strong competition with ammonia for the oxidizer (nitrate). Nitrogen products included N{sub 2}, N{sub 2}O, NO{sub 2{sup {minus}}} as well as toxic NO and trace amounts of NO{sub 2}. Carbon products were CO{sub 2}, HCO{sub 3{sup {minus}}}, CO{sub 3}{sup 2{minus}}, and CO.

  8. 33 CFR 126.28 - Ammonium nitrate, ammonium nitrate fertilizers, fertilizer mixtures, or nitro carbo nitrate...

    Science.gov (United States)

    2010-07-01

    ..., described and defined as an oxidizer by the regulations of 49 CFR part 173 is handled, stored, stowed...) must be eliminated or plugged. Note: See 49 CFR 176.415 for permit requirements for nitro carbo nitrate... nitrate fertilizers, fertilizer mixtures, or nitro carbo nitrate; general provisions. 126.28 Section...

  9. Effect of Ammonium Nitrate on Nanoparticle Size Reduction

    Directory of Open Access Journals (Sweden)

    Kalyana C. Pingali

    2008-01-01

    Full Text Available Ammonium nitrate was added to the spraying solution as a foaming agent to reduce the particle size of nanoparticles synthesized in the spray-pyrolysis process. Ammonium nitrate was effective in breaking the aerosol droplet size and generating nanoparticles that were of approximately one order-of-magnitude (from 200 to 20 nm smaller diameter than those created in the absence of ammonium nitrate in the feed solution. This technique makes it possible to control the particle diameter of metallic nanoparticles below 20 nm.

  10. Effect of ammonium nutrition on the nitrate utilization, nitrate reductase actvity and growth of Spirodela polyrrhiza

    Directory of Open Access Journals (Sweden)

    Ewa Tatkowska

    2014-02-01

    Full Text Available The influence of NH4+ ions on nitrate assimilation and growth of sterile Spirodela polyrrhiza cultures was investigated. S. polyrrhiza utilises both the nitrate and the ammonium form of nitrogen, it prefers, however, NH4+. Ammonium ions present in the nitrate medium inhibit the activity of nitrate reductase (NR, but they do not affect enzyme 'induction and only slightly reduce N03- uptake. These results sugest that the inhibitory effect of NH4+ on the NR activity is the main cause of the decrease in N03- assimilation by S. polyrrhiza cultures growing in nitrate-ammonium medium.

  11. Electrodialysis of Pu-contaminated ammonium nitrate solution

    International Nuclear Information System (INIS)

    Ammonium nitrate is the major component of Pu-contaminated liquid waste generated at the Pu-fuel facilities, and its safe decomposition was experimented by the method of electrodialysis. The process consists of two steps. The one is the electrodialysis of ammonium nitrate to ammonium nitrite in aqueous solution, and the other is the thermal decomposition of the ammonium nitrite to water and nitrogen gas also in aqueous solution. A thermal decomposition column and a heat exchanger were used for the continuous decomposition experiments. The membrane was a cation exchange membrane, the anolyte was 0.1 - 0.5 mol nitric acid, the catholyte was 10 - 50 weight % ammonium nitrate, and the current density was 10 - 50 amp/dm2. The experimental results of the pH and temperature effects on the current efficiency show that electrodialysis is preferable in alkaline region and at lower temperature. It is important to control such minor reactions as ammonium hydroxide byproduction as little as possible. The minor reaction of nitrogen gas generation greatly reduces the current efficiency of ammonium nitrite production. The best current efficiency achieved in the experiments was 85% by selecting the best operating conditions. In order to achieve high current efficiency in electrodialysis, the selection of electrolyzer composition, anode, cation exchange membrane, etc. is indispensable. It is generally preferable to choose the metal which has high hydrogen overvoltage to achieve high current efficiency by controlling hydrogen gas generation. (Wakatsuki, Y.)

  12. Handling of Ammonium Nitrate Mother-Liquid Radiochemical Production - 13089

    International Nuclear Information System (INIS)

    The aim of the work is to develop a basic technology of decomposition of ammonium nitrate stock solutions produced in radiochemical enterprises engaged in the reprocessing of irradiated nuclear fuel and fabrication of fresh fuel. It was necessary to work out how to conduct a one-step thermal decomposition of ammonium nitrate, select and test the catalysts for this process and to prepare proposals for recycling condensation. Necessary accessories were added to a laboratory equipment installation decomposition of ammonium nitrate. It is tested several types of reducing agents and two types of catalyst to neutralize the nitrogen oxides. It is conducted testing of modes of the process to produce condensation, suitable for use in the conversion of a new technological scheme of production. It is studied the structure of the catalysts before and after their use in a laboratory setting. It is tested the selected catalyst in the optimal range for 48 hours of continuous operation. (authors)

  13. Ammonium and nitrate tolerance in lichens

    International Nuclear Information System (INIS)

    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. - Eutrophication has become a global threat for lichen diversity.

  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. Ammonium and potassium effect on nitrate assimilation in cucumber seedlings

    Directory of Open Access Journals (Sweden)

    J. Buczek

    2015-05-01

    Full Text Available The effect of ammonium present in the induction medium toghether with nitrate on the activity of nitrate reductase (NR, nitrite reductase (NiR, glutamic acid dehydrogenase (GDH and absorption and accumulation of NO3- in cucumber seedlings were investigated. Maximum NR and NiR activity in the cotyledons was observed when seedlings were supplied with KNO3 as the sole source of nitrogen. When plants were supplied with NH4NO3 the presence of NH4+ in the induction medium repressed by about 50 per cent the activity of both reductases in the cotyledons. Addition of K+ to this medium abolished completely the inhibitory effect of NH4+. The effect of K+ cannot be replaced by that Na+ ions. On the other hand, ammonium has no effect on the level of NR activity in roots, while NiR was almost completely repressed. Under the experimental conditions ammonium, in the presence of nitrates, decreased the activity of GDH, but this diminution did not occur when the plants were supplied with K+ simultaneously. It has found that NH4+ ions reduced NO3- absorption but at the same time, the ratio of NO3- absorbed to that reduced was increased more than twice. The presumable mechanism of these phenomena is discussed.

  16. 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.

  17. 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.

  18. 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.

  19. Assessment of the potential for ammonium nitrate formation and reaction in Tank 241-SY-101

    International Nuclear Information System (INIS)

    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

  20. 76 FR 23569 - Termination of the Suspension Agreement on Solid Fertilizer Grade Ammonium Nitrate From the...

    Science.gov (United States)

    2011-04-27

    ... Antidumping Duty Investigation: Solid Fertilizer Grade Ammonium Nitrate from the Russian Federation, 64 FR... Less Than Fair Value: Solid Fertilizer Grade Ammonium Nitrate from the Russian Federation, 65 FR 1139..., Investigation No. 731-TA-856 (Preliminary), 64 FR 50103 (September 15, 1999)). On January 7, 2000,...

  1. 76 FR 39847 - Solid Fertilizer Grade Ammonium Nitrate From the Russian Federation; Final Results of the...

    Science.gov (United States)

    2011-07-07

    ...: Solid Fertilizer Grade Ammonium Nitrate From the Russian Federation, 64 FR 45236 (August 19, 1999). On... Fertilizer Grade Ammonium Nitrate From the Russian Federation, 65 FR 42669 (July 11, 2000) (``Final... Results of Review.'' \\1\\ See Initiation of Five-Year (``Sunset'') Review, 76 FR 11202 (March 1,...

  2. 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...

  3. Nitrogen phosphoric fertilizer production technology on the base of Central Kyzylkum phosphorites and ammonium nitrate melt

    OpenAIRE

    Shavkat Namazov; Akhmed Reymov; Nazarkul Pirmanov; Rashid Kurbaniyazov

    2012-01-01

    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.

  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. Ammonium nitrate as an oxidizer in solid composite propellants

    Science.gov (United States)

    Manelis, G. B.; Lempert, D. B.

    2009-09-01

    Despite the fact that ammonium nitrate (AN) has the highest hydrogen content and fairly high oxygen balance (compared to other oxidizers), its extremely low formation enthalpy and relatively low density makes it one of the worst power oxidizers in solid composite propellants (SCP). Nevertheless, AN has certain advantages - the combustion of the compositions containing AN is virtually safe, its combustion products are ecologically clean, it is very accessible and cheap, and also very thermostable (far more stable than ammonium dinitramide (ADN)). Besides, its low density stops being a disadvantage if the propellant has to be used in deep space and therefore, must be carried there with other rocket carriers. The low cost of AN may also become a serious advantage in the AN application even in lower stages of multistage space launchers as well as in one-stage space launchers with low mass fraction of the propellant. The main specific features relevant to the creation of AN-based SCPs with the optimal energetic characteristics are discussed. The use of metals and their hydrides and proper fuel-binders as well as the recent successes in phase stabilization of AN are described.

  6. Development of electrochemical denitrification from waste water containing ammonium nitrate

    International Nuclear Information System (INIS)

    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 NH4NO3 waste water of 1.5 M by 3 stages of electrodialysis cells. To recover nitric acid and ammonium water, they separated HNO3 solution of 6 M and NH4OH solution with one unit of electrolysis cell, then absorbed NH3 gas from NH4OH solution with water and applied the condition of operation to recover 8 M NH4OH 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 NH4NO3 waste water of 4,500 mol can be treated per day

  7. 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

  8. The Comparison of Ammonium or Nitrate-Grown Lettuce and Spinach in a Hydroponic System

    Directory of Open Access Journals (Sweden)

    H. R. Roosta

    2010-06-01

    Full Text Available Most plant species are sensitive to high ammonium concentrations. In this experiment the sensitivity of lettuce and spinach to ammonium was investigated. In a factorial experiment with framework of a completely randomized design with two factors, nitrogen form (ammonium and nitrate and plant species (lettuce and spinach, and three replications seeds were germinated in a mixture of perlite, sand and clay in soil-maid pots. After two weeks, the seedlings at two true-leaf stage were then transferred to buckets containing 4 L of aerated nutrient solution. The four plants were growing together. The treatments were ammonium and nitrate at 5 mM. In comparison to nitrate, ammonium reduced the growth of both species. Concentration of K, Mg, and Na decreased with ammonium in both species. The reduction of K and Mg concentrations in ammonium-fed plants may have a role in ammonium toxicity. Ammonium nutrition of both species caused an increase in P at roots and shoots. Higher P content at ammonium-fed lettuce and spinach plants may be due to creation of cations and anions balance in plants. Chlorophyll a and b were higher in ammonium-fed than nitrate-fed plants.

  9. Stoichiometric analysis of ammonium nitrate and ammonium perchlorate with nanosecond laser induced breakdown spectroscopy

    Science.gov (United States)

    Sreedhar, S.; Rao, S. Venugopal; Kiran, P. Prem; Tewari, Surya P.; Kumar, G. Manoj

    2010-04-01

    We present our results on the stoichiometric analysis of ammonium nitrate (AN) and ammonium Perchlorate (AP) studied using laser induced breakdown spectroscopy (LIBS) with nanosecond pulses. The LIBS spectra collected for AP and AN, without any gating and using a high resolution spectrometer, exhibited characteristic lines corresponding to O, N, H, C, and K. The Oxygen line at 777.38 nm and three Nitrogen lines (N1, N2, N3) at 742.54 nm, 744.64 nm, 747.12 nm were used for evaluating the Oxygen/Nitrogen ratios. The intensities were calculated using area under the peaks and normalized to their respective transition probabilities and statistical weights. The O/N1 ratios estimated from the LIBS spectra were ~4.94 and ~5.11 for AP and O/N3 ratios were ~1.64 and ~1.47 for AN obtained from two independent measurements. The intensity ratios show good agreement with the actual stoichiometric ratios - four for AP and one for AN.

  10. An 15N study of the effects of nitrate, ammonium, and nitrate + ammonium nutrition on nitrogen assimilation in Zea mays L

    International Nuclear Information System (INIS)

    A brief review of the literature on the effects of nitrate and ammonium nitrogen sources on plant growth, and the assimilation of those nitrogen sources, has been presented. It was concluded that ammonium nutrition produces optimum growth, with nitrate + ammonium being a better nitrogen source than only nitrate. Leaf blade nitrate reductase activity exceeded that of the root in nitrate-fed plants, suggesting that the shoot is the major region of nitrate assimilation. This is further supported by the results of xylem exudate analysis, where 93% of the newly-absorbed nitrogen exported by the roots was detected as nitrate. Evidence in support of this hypothesis was also obtained by studying the distribution of 15N in the various nitrogenous compounds. The effects of nitrogen source on plant growth, organic nitrogen and inorganic nitrogen contents, and the rates of incorporation into nitrogenous compounds were studied. The observed differences were explained with reference to the effects of the various nitrogen sources on the physiology of the plants. The experimental techniques included assays of the enzymes nitrate reductase and glutamine synthetase, whole plant growth studies, and the analysis of nitrogenous compounds of xylem exudate and those extracted from the leaf blade, leaf base, and root regions of maize plants after feeding with a nutrient solution containing nitrogen as 15N

  11. Investigation of the wettability of ammonium nitrate prills

    Energy Technology Data Exchange (ETDEWEB)

    Kwok, Q.S.M.; Jones, D.E.G.; Kruus, P.

    2003-03-01

    The wetting characteristics of a variety of powders or porous materials can be determined through capillary penetration methods. Wettability of ammonium nitrate (AN) prills determines, in large part, the physical stability and detonation behaviour of ANFO (admixtures of AN prills with fuel oil). This study compared the wettabilities of a variety of AN prills with alkanes and fuel oil. Complementary characterization studies using scanning electron microscopy and thermogravimetry were also performed to justify the differences in wettability. Several factors affected wettability, including surface tension, viscosity, density, purity, polarity and polarizability of the liquid used. Surface composition, porosity, bulk density, particle size and moisture content of the AN samples were also contributing factors to wettability. The explosive-grade (porous) AN prill demonstrated a better wettability due the combined effects of these factors. Thermodesorption of octane from various AN prills was examined using high-resolution thermogravimetry. The adsorption capacity, porosity and specific surface area of 3 different AN prills were evaluated from the mass-loss curves to reflect the evaporation of the excess liquid and the thermodesorption of octane from the pores and the surface of the AN prills. The amount of octane desorbed in these steps was correlated with the volume in the pores and the quantity adsorbed on the surface. The porosity and surface area adsorption capacity of an AN prill was then estimated. 15 refs., 5 tabs., 10 figs.

  12. Study of incompatibility of ammonium nitrate and its mechanism of decomposition by theoretical approach

    OpenAIRE

    Cagnina, Stefania; ROTUREAU, Patricia; Adamo, Carlo

    2013-01-01

    The dramatic accident involving ammonium nitrate (AN) that took place at Toulouse in September 2001 has once again focused attention to the complex hazards pertaining to this chemical. Despite the significant efforts made to increase AN safety over the whole supply chain, we are still facing insufficient knowledge of the actual mechanisms of ammonium nitrate decomposition that may take place in abnormal situations. The paper proposes a theoretical study of chemical incompatibilities of ammoni...

  13. Formation rate of ammonium nitrate in the off-gas line of SRAT and SME in DWPF

    International Nuclear Information System (INIS)

    A mathematical model for the formation rate of ammonium nitrate in the off-gas line of the Sludge Receipt and Adjustment Tank (SRAT) and the Slurry Mixed Evaporator (SME) in DWPF has been developed. The formation rate of ammonium nitrate in the off-gas line depends on pH, temperature, volume and total concentration of ammonia and ammonium ion. Based on a typical SRAT and SME cycle in DWPF, this model predicts the SRAT contributes about 50 lbs of ammonium nitrate while SME contributes about 60 lbs of ammonium nitrate to the off-gas line

  14. Energetic valorization of ammonium resulting from nitrate electrochemical reduction—Feasibility of biohydrogen production

    OpenAIRE

    Abdallah, Rawa; Amrane, Abdeltif; Djelal, Hayet; Taha, Samir; Fourcade, Florence; Labasque, Thierry; Geneste, Florence; Floner, Didier

    2015-01-01

    The main objective of this work was to examine the feasibility of coupling electrochemical and biological processes to destroy nitrate ions (NO3−) while producing biohydrogen. In this integrated process NO3− was firstly converted to ammonium using an electrochemical flow cell. After only one pass of concentrated nitrate solutions (3 g NO3− L−1) through the flow cell, ammonium ions selectivity of 98.8%, corresponding to 0.86 g NH4+ L−1 was recorded. The obtained ammonium solution was then test...

  15. an investigation of the ammonium poly uranate precipitation via uranyl nitrate solution

    International Nuclear Information System (INIS)

    a series of experiments were made concerning the interaction of uranyl nitrate with ammonium hydroxide solution, with the aim of preparing ammonium poly uranate (APU) as an intermediate product during nuclear reactors fuel fabrication. the particle size and final product characteristics of the uranium oxide depend greatly on the ways of preparation of the APU , in the present work, the kinetics of deposition and the composition of the formed products upon adding increasing amounts of ammonium hydroxide to uranyl nitrate solution have been followed in a trial to understand the prevailing mechanisms

  16. Development of miniaturized potentiometric nitrate- and ammonium selective electrodes for applications in water monitoring

    Energy Technology Data Exchange (ETDEWEB)

    Schwarz, J.; Kaden, H. [Kurt-Schwabe-Institut fuer Mess- und Sensortechnik e.V., Meinsberg (Germany); Pausch, G. [Umwelt- und Ingenieurtechnik GmbH, Dresden (Germany)

    2000-06-01

    Mobile analysis with potentiometric sensors is well suited for field measurements. Ion-selective electrodes (ISE) based on polymeric membranes for in-situ determination of nitrate and ammonium contents in ground water, drinking water and surface water have been developed. The ISE are integrated in a multisensor module (MSM) for monitoring these ions over longer time intervals. The receptor is a PVC-membrane with tridodecylammonium nitrate (TDDA) for nitrate- and nonactine for ammonium-electrodes as ionophores. As plasticizer dibutylphthalate (DBT) was used. The main parameters for assessing the efficiency of these ISE are presented. (orig.)

  17. Thermal stability and kinetics of decomposition of ammonium nitrate in the presence of pyrite

    Energy Technology Data Exchange (ETDEWEB)

    Gunawan, Richard, E-mail: R.Gunawan@curtin.edu.au [Centre for Fuels and Energy, Curtin University of Technology, G.P.O. Box U1987, Perth, WA 6845 (Australia); Zhang Dongke [Centre for Petroleum, Fuels and Energy, School of Mechanical Engineering (M050), University of Western Australia, 35 Stirling Highway, Crawley WA 6009 (Australia)

    2009-06-15

    The interaction between ammonium nitrate based industrial explosives and pyrite-rich minerals in mining operations can lead to the occurrence of spontaneous explosion of the explosives. In an effort to provide a scientific basis for safe applications of industrial explosives in reactive mining grounds containing pyrite, ammonium nitrate decomposition, with and without the presence of pyrite, was studied using a simultaneous Differential Scanning Calorimetry and Thermogravimetric Analyser (DSC-TGA) and a gas-sealed isothermal reactor, respectively. The activation energy and the pre-exponential factor of ammonium nitrate decomposition were determined to be 102.6 kJ mol{sup -1} and 4.55 x 10{sup 7} s{sup -1} without the presence of pyrite and 101.8 kJ mol{sup -1} and 2.57 x 10{sup 9} s{sup -1} with the presence of pyrite. The kinetics of ammonium nitrate decomposition was then used to calculate the critical temperatures for ammonium nitrate decomposition with and without the presence of pyrite, based on the Frank-Kamenetskii model of thermal explosion. It was shown that the presence of pyrite reduces the temperature for, and accelerates the rate of, decomposition of ammonium nitrate. It was further shown that pyrite can significantly reduce the critical temperature of ammonium nitrate decomposition, causing undesired premature detonation of the explosives. The critical temperature also decreases with increasing diameter of the blast holes charged with the explosive. The concept of using the critical temperature as indication of the thermal stability of the explosives to evaluate the risk of spontaneous explosion was verified in the gas-sealed isothermal reactor experiments.

  18. Thermal stability and kinetics of decomposition of ammonium nitrate in the presence of pyrite.

    Science.gov (United States)

    Gunawan, Richard; Zhang, Dongke

    2009-06-15

    The interaction between ammonium nitrate based industrial explosives and pyrite-rich minerals in mining operations can lead to the occurrence of spontaneous explosion of the explosives. In an effort to provide a scientific basis for safe applications of industrial explosives in reactive mining grounds containing pyrite, ammonium nitrate decomposition, with and without the presence of pyrite, was studied using a simultaneous Differential Scanning Calorimetry and Thermogravimetric Analyser (DSC-TGA) and a gas-sealed isothermal reactor, respectively. The activation energy and the pre-exponential factor of ammonium nitrate decomposition were determined to be 102.6 kJ mol(-1) and 4.55 x 10(7)s(-1) without the presence of pyrite and 101.8 kJ mol(-1) and 2.57 x 10(9)s(-1) with the presence of pyrite. The kinetics of ammonium nitrate decomposition was then used to calculate the critical temperatures for ammonium nitrate decomposition with and without the presence of pyrite, based on the Frank-Kamenetskii model of thermal explosion. It was shown that the presence of pyrite reduces the temperature for, and accelerates the rate of, decomposition of ammonium nitrate. It was further shown that pyrite can significantly reduce the critical temperature of ammonium nitrate decomposition, causing undesired premature detonation of the explosives. The critical temperature also decreases with increasing diameter of the blast holes charged with the explosive. The concept of using the critical temperature as indication of the thermal stability of the explosives to evaluate the risk of spontaneous explosion was verified in the gas-sealed isothermal reactor experiments. PMID:19056177

  19. Thermodynamic interpretation on solubility of neptunium, technetium, selenium and palladium in nitrate and ammonium solutions

    International Nuclear Information System (INIS)

    We conducted thermodynamic interpretation of solubility data on neptunium, technetium and selenium, which are redox-sensitive elements, in nitrate solutions. Experimentally measured solubility values were compared with thermodynamic calculations using the thermodynamic database (JAEA-TDB) developed by Japan Atomic Energy Agency. Most of experimental data were in a good agreement with calculated values. It was found that nitrate might have a potential to oxidize neptunium and technetium, which might lead significant increase of their solubility. Detail of migration behavior of nitrate and ammonium should be investigated for performance assessment of radioactive waste containing a significant amount of nitrate. (author)

  20. Efficiency of energy transfer from γ-irradiated ammonium halides in aqueous iodide and nitrate solutions

    International Nuclear Information System (INIS)

    It is well known that ammonium halide (NH4X) crystals, on γ-exposure, store energy in the form of primary and secondary radiolytic products. Such crystals on dissolution in aqueous iodide and nitrate solutions result in oxidation of iodide and reduction of nitrate, respectively. The yields of iodine and nitrite are determined by chemical methods under varying conditions of the amount, dose and particle size of the irradiated ammonium halide salts. The maximum values of the efficiency of energy transfer for oxidation and reduction processes for ammonium halide salts correspond to 40% and 10%, respectively. At low doses, an empirical relation proposed between the percent efficiency of energy transfer and the absorbed dose is valid. The concentrations of inherent oxidizing and reducing species initially present are 7.0*1018 and 1.0*1018 per mol of ammonium halide, respectively. (author) 21 refs.; 7 figs.; 2 tabs

  1. Nitrogen (15N) recovery from ammonium and nitrate applied to the soil by sugar cane

    International Nuclear Information System (INIS)

    An experiment was developed in a field aimed to compare the recovery of the ammonium-15 N and nitrate-15 N by the sugar cane plants harvested mechanically without burning. A rate of 70 kg ha-1 of N was applied as ammonium nitrate, in strip, onto cultural residues. Two lineal meters micropots were used. They received the fertilizer labeled with 15 N. Two treatments were established using labeled ammonium (NH4+-15 N) or nitrate (NO3-15 N). Two months after fertilization, four samples of the aerial part (two lineal meters) for treatment in the portions that did not receive the fertilizer-15 N, were taken in order to evaluated the fitomass production (Mg ha-1) and N-total accumulated (kg ha-1). This evaluation was repeated every two months up to complete five of them. Two leaves (leaves with 3 deg C visible auricle) were collected from plants that were in a middle of the micropots (15 N) and in corresponding positions in the adjacent rows, to evaluated the concentration of 15 N. There was a larger absorption of the nitrate-N (30.5%) than of the ammonium-N (21.2%). On the other hand, in the soil the results showed larger ammonium-15 N residual effect concentration, probably due to microorganism immobilization. (author)

  2. Effects of potassium nitrate on the solid phase transitions of ammonium nitrate particles

    Science.gov (United States)

    Wu, Hong Bo; Chan, Chak K.

    Ammonium nitrate (NH 4NO 3) is a common constituent of atmospheric particulate pollutants. It exists in five stable polymorphic forms, designated as phases V, IV, III, II and I, below its melting point of 170 °C. In atmospheric research, very little attention has been paid to the solid phase transitions of NH 4NO 3 because phase IV NH 4NO 3 particles are stable over a wide range of tropospheric temperatures. Potassium nitrate (KNO 3) is often found to co-exist with NH 4NO 3 in atmospheric aerosols, and it can change the phase transition behaviors of solid NH 4NO 3 particles. In this study, we investigated the effects of KNO 3 on the solid phase transitions of NH 4NO 3 particles using in situ microscopic Raman spectroscopy. Both the transition path and transition temperature of NH 4NO 3 single particles (40-700 μm) depend on the KNO 3 mass percentage and the particle size. With the addition of KNO 3, the IV→II transition, which appears at 52 °C for pure NH 4NO 3 particles, is replaced by the IV→III transition. The KNO 3 mass percentage required for this change in transition path increases with decreasing particle size and the transition temperature decreases with increasing KNO 3 mass percentage. At a relatively high mass percentage of KNO 3 (⩾7.4 wt%), the KNO 3/NH 4NO 3 mixed particles undergo the IV→III transition under ambient temperatures, or even crystallize directly in phase III from droplets with a further increase in the mass percentage of KNO 3. Submicron KNO 3/NH 4NO 3 particles crystallize to phase IV at low KNO 3 mass percentages (⩽5.7 wt%) but to phase III at higher KNO 3 mass percentages (⩾7.4 wt%). These results suggest that atmospheric solid NH 4NO 3 particles may exist in phase III and the phase transitions should not be ignored in atmospheric chemical models.

  3. Regulation of assimilatory nitrate reductase activity in soil by microbial assimilation of ammonium.

    OpenAIRE

    McCarty, G.W.; Bremner, J. M.

    1992-01-01

    It is well established that assimilatory nitrate reductase (ANR) activity in soil is inhibited by ammonium (NH4+). To elucidate the mechanism of this inhibition, we studied the effect of L-methionine sulfoximine (MSX), an inhibitor of NH4+ assimilation by microorganisms, on assimilatory reduction of nitrate (NO3-) in aerated soil slurries treated with NH4+. We found that NH4+ strongly inhibited ANR activity in these slurries and that MSX eliminated this inhibition. We also found that MSX indu...

  4. Dissimilatory nitrate reduction to ammonium and responsible microflora in two contrasting paddy-rice soils

    International Nuclear Information System (INIS)

    The purpose of this study was to compare nitrate reduction, and the responsible microflora, in two soils contrasting in their potential for dissimilatory nitrate reduction to ammonium (DNRA). A soil from Griffith (NSW) reduced 14.5% of applied 15N-labelled nitrate to ammonium and organic-N under laboratory incubation without any exogenous carbon sources. A soil from Yangzhou (China) reduced only 4.7%. Addition of reducing agents (sodium thioglycollate and L-cysteine) enhanced the DNRA process, with most of the product of nitrate reduction being ammonium. Additions of glucose also facilitated DNRA, with most of the product being organic-N. There was a small but measurable amount of nitrous oxide production during nitrate reduction. Nitrous oxide production accounted for 0.05 to 4.2% of added nitrate by the end of experiments. Nitrous oxide tended to dissipate as the incubation proceeded in all non-glucose treatments, whereas in glucose treatments it tended to accumulate. The denitrifier population in the Griffith soil was about a tenth of the size of that in the Yangzhou soil. The DNRA population in Griffith soil, in contrast, was larger than that in Yangzhou soil. Of DNRA bacteria and denitrifiers isolated, spore-former dominated. (author)

  5. 27 CFR 555.220 - Table of separation distances of ammonium nitrate and blasting agents from explosives or blasting...

    Science.gov (United States)

    2010-04-01

    .... Department of Transportation (49 CFR part 173). (5) Earth or sand dikes, or enclosures filled with the... distances of ammonium nitrate and blasting agents from explosives or blasting agents. 555.220 Section 555... ammonium nitrate and blasting agents from explosives or blasting agents. Table: Department of...

  6. Simulation of nitrate, sulfate, and ammonium aerosols over the United States

    Directory of Open Access Journals (Sweden)

    J. M. Walker

    2012-08-01

    Full Text Available Atmospheric concentrations of inorganic gases and aerosols (nitrate, sulfate, and ammonium are simulated for 2009 over the United States using the chemical transport model GEOS-Chem. This work is motivated, in part, by the inability of previous modeling studies to reproduce observed high nitrate aerosol concentrations in California. Nitrate aerosol concentrations over most of the US are over-predicted relative to Interagency Monitoring of Protected Visual Environments (IMPROVE and Clean Air Status and Trends Network (CASTNET data. In California, on the other hand, nitrate and ammonium are under-predicted as compared to California Air Resources Board (CARB measurements. Over-prediction of nitrate in the East and Midwest is consistent with results of recent studies, which have suggested that nighttime nitric acid formation by heterogeneous hydrolysis of N2O5 is over-predicted with current values of the N2O5 uptake coefficient, γ, onto aerosols. Accordingly, the value of γ is reduced here by a factor of 10. Despite this, predicted nitrate levels in the US Midwest remain higher than those measured and over-prediction of nitrate in this region remains to be explained. Data from the Infrared Atmospheric Sounding Interferometer (IASI onboard the MetOp-A satellite indicate the presence of a strong ammonia maximum in central and southern California that is not present in the simulations, which are based on the EPA National Emissions Inventory (NEI NH3 emission inventory. In order to predict ammonia columns similar to the satellite measurements in the San Joaquin Valley, CA and Riverside, CA, the current ammonia emission inventory in California would need to be increased substantially. Based on the sensitivity of ammonium nitrate formation to the availability of ammonia, the present results suggest that under-prediction of ammonia emissions is likely the main cause for the under-prediction of

  7. Evaluation of natural zeolite clinoptilolite efficiency for the removal of ammonium and nitrate from aquatic solutions

    Directory of Open Access Journals (Sweden)

    Mozhdeh Murkani

    2015-01-01

    Full Text Available Background: Surface water and groundwater pollution with various forms of nitrogen such as ammonium and nitrate ions is one of the main environmental risks. The major objectives of this study were to evaluate the capacity of natural zeolite (clinoptilolite to remove NO3– and NH4+ from polluted water under both batch and column conditions. Methods: The laboratory batch and column experiments were conducted to investigate the feasibility of clinoptilolite as the adsorbent for removal of nitrate (NO3– and ammonium (NH4+ ions from aqueous solution. The effects of pH, clinoptilolite dosage, contact time, and initial metal ion concentration on NO3– and NH4+ removal were investigated in a batch system. Results: Equilibrium time for NO3– and NH4+ ions exchange was 60 minutes and the optimum adsorbent dosage for their removal was 1 and 2.5 g/L, respectively. The adsorption isotherm of reaction (r> 0.9 and optimum entered concentration of ammonium and nitrate (30 and 6.5 mg/L, respectively were in accordance with Freundlich isotherm model. The ammonium removal rate increased by 98% after increasing the contact time. Conclusion: Our findings confirmed that natural Clinoptilolite can be used as one of effective, suitable, and low-costing adsorbent for removing ammonium from polluted waters.

  8. Winter Wheat and Maize Response to Urea Ammonium Nitrate and a New Urea Formaldehyde Polymer Fertilizer

    Science.gov (United States)

    Slow release nitrogen (N) fertilizers have potential to improve yield and nitrogen use efficiency (NUE) in winter wheat (Triticum aestivum L.) and maize (Zea mays L.). A slow release urea formaldehyde polymer (UFP) was compared with conventional aqueous urea-ammonium nitrate (UAN) [(NH2)2CO, NH4NO3]...

  9. 76 FR 49449 - Continuation of Antidumping Duty Order on Solid Fertilizer Grade Ammonium Nitrate From the...

    Science.gov (United States)

    2011-08-10

    ... Initiation of Five-Year (``Sunset'') Review, 76 FR 11202 (March 1, 2011) and Ammonium Nitrate from Russia, Investigation No. 731-TA-856 (Second Review), 76 FR 11273 (March 1, 2011). On March 3, 2011, the Department..., 76 FR 23569 (April 27, 2011). As a result of its review, the Department determined that...

  10. Lessons to be learned from an analysis of ammonium nitrate disasters in the last 100 years

    International Nuclear Information System (INIS)

    Highlights: • Root causes and contributing factors from ammonium nitrate incidents are categorized into 10 lessons. • The lessons learned from the past 100 years of ammonium nitrate incidents can be used to improve design, operation, and maintenance procedures. • Improving organizational memory to help improve safety performance. • Combating and changing organizational cultures. - Abstract: Process safety, as well as the safe storage and transportation of hazardous or reactive chemicals, has been a topic of increasing interest in the last few decades. The increased interest in improving the safety of operations has been driven largely by a series of recent catastrophes that have occurred in the United States and the rest of the world. A continuous review of past incidents and disasters to look for common causes and lessons is an essential component to any process safety and loss prevention program. While analyzing the causes of an accident cannot prevent that accident from occurring, learning from it can help to prevent future incidents. The objective of this article is to review a selection of major incidents involving ammonium nitrate in the last century to identify common causes and lessons that can be gleaned from these incidents in the hopes of preventing future disasters. Ammonium nitrate has been involved in dozens of major incidents in the last century, so a subset of major incidents were chosen for discussion for the sake of brevity. Twelve incidents are reviewed and ten lessons from these incidents are discussed

  11. Potential rates of ammonium oxidation, nitrite oxidation, nitrate reduction and denitrification in the young barley rhizosphere

    DEFF Research Database (Denmark)

    Højberg, Ole; Binnerup, S. J.; Sørensen, Jan

    1996-01-01

    Potential activities (enzyme contents) of ammonium (NH4+) oxidizing, nitrite (NO2-) oxidizing, nitrate (NO3-) reducing and denitrifying bacteria were measured in bulk and rhizosphere soil obtained from young barley plants in the field. The activities as well as pools of inorganic N (NH4+, NO2- and...

  12. Lessons to be learned from an analysis of ammonium nitrate disasters in the last 100 years

    Energy Technology Data Exchange (ETDEWEB)

    Pittman, William; Han, Zhe; Harding, Brian; Rosas, Camilo; Jiang, Jiaojun; Pineda, Alba; Mannan, M. Sam, E-mail: mannan@tamu.edu

    2014-09-15

    Highlights: • Root causes and contributing factors from ammonium nitrate incidents are categorized into 10 lessons. • The lessons learned from the past 100 years of ammonium nitrate incidents can be used to improve design, operation, and maintenance procedures. • Improving organizational memory to help improve safety performance. • Combating and changing organizational cultures. - Abstract: Process safety, as well as the safe storage and transportation of hazardous or reactive chemicals, has been a topic of increasing interest in the last few decades. The increased interest in improving the safety of operations has been driven largely by a series of recent catastrophes that have occurred in the United States and the rest of the world. A continuous review of past incidents and disasters to look for common causes and lessons is an essential component to any process safety and loss prevention program. While analyzing the causes of an accident cannot prevent that accident from occurring, learning from it can help to prevent future incidents. The objective of this article is to review a selection of major incidents involving ammonium nitrate in the last century to identify common causes and lessons that can be gleaned from these incidents in the hopes of preventing future disasters. Ammonium nitrate has been involved in dozens of major incidents in the last century, so a subset of major incidents were chosen for discussion for the sake of brevity. Twelve incidents are reviewed and ten lessons from these incidents are discussed.

  13. On-site semi-quantitative analysis for ammonium nitrate detection using digital image colourimetry.

    Science.gov (United States)

    Choodum, Aree; Boonsamran, Pichapat; NicDaeid, Niamh; Wongniramaikul, Worawit

    2015-12-01

    Digital image colourimetry was successfully applied in the semi-quantitative analysis of ammonium nitrate using Griess's test with zinc reduction. A custom-built detection box was developed to enable reproducible lighting of samples, and was used with the built-in webcams of a netbook and an ultrabook for on-site detection. The webcams were used for colour imaging of chemical reaction products in the samples, while the netbook was used for on-site colour analysis. The analytical performance was compared to a commercial external webcam and a digital single-lens reflex (DSLR) camera. The relationship between Red-Green-Blue intensities and ammonium nitrate concentration was investigated. The green channel intensity (IG) was the most sensitive for the pink-violet products from ammonium nitrate that revealed a spectrometric absorption peak at 546 nm. A wide linear range (5 to 250 mgL⁻¹) with a high sensitivity was obtained with the built-in webcam of the ultrabook. A considerably lower detection limit (1.34 ± 0.05mgL⁻¹) was also obtained using the ultrabook, in comparison with the netbook (2.6 ± 0.2 mgL⁻¹), the external web cam (3.4 ± 0.1 mgL⁻¹) and the DSLR (8.0 ± 0.5 mgL⁻¹). The best inter-day precision (over 3 days) was obtained with the external webcam (0.40 to 1.34%RSD), while the netbook and the ultrabook had 0.52 to 3.62% and 1.25 to 4.99% RSDs, respectively. The relative errors were +3.6, +5.6 and -7.1%, on analysing standard ammonium nitrate solutions of known concentration using IG, for the ultrabook, the external webcam, and the netbook, respectively, while the DSLR gave -4.4% relative error. However, the IG of the pink-violet reaction product suffers from interference by soil, so that blank subtraction (|IG-IGblank| or |AG-AGblank|) is recommended for soil sample analysis. This method also gave very good accuracies of -0.11 to -5.61% for spiked soil samples and the results presented for five seized samples showed good correlations between

  14. Decreasing ammonium generation using hydrogenotrophic bacteria in the process of nitrate reduction by nanoscale zero-valent iron

    International Nuclear Information System (INIS)

    An integrated nitrate treatment using nanoscale zero-valent iron (NZVI) and Alcaligenes eutrophus, which is a kind of hydrogenotrophic denitrifying bacteria, was conducted to remove nitrate and decrease ammonium generation. Within 8 days, nitrate was removed completely in the reactors containing NZVI particles plus bacteria while the proportion of ammonium generated was only 33%. That is a lower reduction rate but a smaller proportion of ammonium relative to that in abiotic reactors. It was also found that ammonium generation experienced a biphasic process, involving an increasing period and a stable period. After domestication of the bacteria, the combined NZVI-cell system could remove all nitrate without ammonium released when the refreshed nitrate was introduced. Nitrate reduction and the final product distribution were also studied in batch reactors amended with different initial NZVI contents and biomass concentrations, respectively. Both the nitrate removal rate and the ammonium yield decreased when the initial content of NZVI reduced and the initial biomass concentration increased. However, about 27% of the nitrate was converted to ammonium when excess bacteria (OD422 = 0.026) were used, which was higher than that with appropriate amount of bacteria.

  15. Decreasing ammonium generation using hydrogenotrophic bacteria in the process of nitrate reduction by nanoscale zero-valent iron

    Energy Technology Data Exchange (ETDEWEB)

    An, Yi; Li, Tielong [College of Environmental Science and Engineering/Tianjin Key Laboratory of Environmental Remediation and Pollution Control/Ministry of Education Key Laboratory of Pollution Processed and Environmental Criteria, Nankai University, Tianjin 300071 (China); Jin, Zhaohui, E-mail: jinzh@nankai.edu.cn [College of Environmental Science and Engineering/Tianjin Key Laboratory of Environmental Remediation and Pollution Control/Ministry of Education Key Laboratory of Pollution Processed and Environmental Criteria, Nankai University, Tianjin 300071 (China); Dong, Meiying; Li, Qianqian; Wang, Shuaima [College of Environmental Science and Engineering/Tianjin Key Laboratory of Environmental Remediation and Pollution Control/Ministry of Education Key Laboratory of Pollution Processed and Environmental Criteria, Nankai University, Tianjin 300071 (China)

    2009-10-15

    An integrated nitrate treatment using nanoscale zero-valent iron (NZVI) and Alcaligenes eutrophus, which is a kind of hydrogenotrophic denitrifying bacteria, was conducted to remove nitrate and decrease ammonium generation. Within 8 days, nitrate was removed completely in the reactors containing NZVI particles plus bacteria while the proportion of ammonium generated was only 33%. That is a lower reduction rate but a smaller proportion of ammonium relative to that in abiotic reactors. It was also found that ammonium generation experienced a biphasic process, involving an increasing period and a stable period. After domestication of the bacteria, the combined NZVI-cell system could remove all nitrate without ammonium released when the refreshed nitrate was introduced. Nitrate reduction and the final product distribution were also studied in batch reactors amended with different initial NZVI contents and biomass concentrations, respectively. Both the nitrate removal rate and the ammonium yield decreased when the initial content of NZVI reduced and the initial biomass concentration increased. However, about 27% of the nitrate was converted to ammonium when excess bacteria (OD{sub 422} = 0.026) were used, which was higher than that with appropriate amount of bacteria.

  16. Influence of ammonium and nitrate salts on the bioelectric potential of oat (Avena sativa L. leaves

    Directory of Open Access Journals (Sweden)

    E. Ślesak

    2015-05-01

    Full Text Available The paper concerns the influence of various forms of nitrogen on the bioelectric potential of leaves of oats growing under different light conditions. The measurements performed demonstrated differences in the bioelectric potential of leaves on plants growing on an ammonium or nitrate substrate. On the ammonium substrate the potential is more negative and the differences are wider at higher light intensities. Analyses of potassium and chlorophyll content in the leaves showed no direct correlation between the potential value and potassium content, whereas an increase in chlorophyll content was associated with an eletronegative potential in the leaves.

  17. Waveguide terahertz time-domain spectroscopy of ammonium nitrate polycrystalline films

    Science.gov (United States)

    Khachatrian, Ani; Melinger, Joseph S.; Qadri, Syed B.

    2012-05-01

    We report temperature-dependent measurements of the terahertz (THz) vibrational spectrum of ammonium nitrate (AN) films and mixed potassium nitrate (KN)-ammonium nitrate films using waveguide THz time domain spectroscopy. The experiments were performed on polycrystalline films on the metal surface of a parallel plate waveguide. At cryogenic temperature and with frequency resolution as high as 7 GHz, our measurements produce a complex vibrational spectrum for AN, and show vibrational resonances not observed in previous far infrared and Raman measurements. We investigate potential interactions between AN and the metal surface by measuring THz spectra of films on aluminum, gold, and a gold surface coated with an organic self-assembled monolayer. Measurements are also performed on a deuterated AN film and indicate that the observed THz modes are due largely to the motion of the nitrate ions in the AN crystal. Finally, the effect of introducing small amounts of an impurity into the AN lattice is examined. We find that introduction of as little as 1%-2% by weight of potassium nitrate into the AN lattice causes line broadening of the THz modes, which is consistent with increased disorder introduced by the impurity.

  18. Simulation of nitrate, sulfate, and ammonium aerosols over the United States

    Directory of Open Access Journals (Sweden)

    J. M. Walker

    2012-11-01

    Full Text Available Atmospheric concentrations of inorganic gases and aerosols (nitrate, sulfate, and ammonium are simulated for 2009 over the United States using the chemical transport model GEOS-Chem. Predicted aerosol concentrations are compared with surface-level measurement data from the Interagency Monitoring of Protected Visual Environments (IMPROVE, the Clean Air Status and Trends Network (CASTNET, and the California Air Resources Board (CARB. Sulfate predictions nationwide are in reasonably good agreement with observations, while nitrate and ammonium are over-predicted in the East and Midwest, but under-predicted in California, where observed concentrations are the highest in the country. Over-prediction of nitrate in the East and Midwest is consistent with results of recent studies, which suggest that nighttime nitric acid formation by heterogeneous hydrolysis of N2O5 is over-predicted based on current values of the N2O5 uptake coefficient, γ, onto aerosols. After reducing the value of γ by a factor of 10, predicted nitrate levels in the US Midwest and East still remain higher than those measured, and over-prediction of nitrate in this region remains unexplained. Comparison of model predictions with satellite measurements of ammonia from the Tropospheric Emissions Spectrometer (TES indicates that ammonia emissions in GEOS-Chem are underestimated in California and that the nationwide seasonality applied to ammonia emissions in GEOS-Chem does not represent California very well, particularly underestimating winter emissions. An ammonia sensitivity study indicates that GEOS-Chem simulation of nitrate is ammonia-limited in southern California and much of the state, suggesting that an underestimate of ammonia emissions is likely the main cause for the under-prediction of nitrate aerosol in many areas of California. An approximate doubling of ammonia emissions is needed to reproduce observed nitrate concentrations in

  19. Thermodynamic Evaluation of Energy Integration and Cogeneration in Ammonium Nitrate Production Complexes

    OpenAIRE

    Kirova-Yordanova, Zornitza

    2013-01-01

    The energy integration and cogeneration are commonly used in large nitrogen and phosphorous fertilizer production complexes for many years, due to the presence in the same site of production processes with highly exothermic main reactions, e.g. nitric and/or sulphuric acid plants and heat consuming processes, e.g. urea, ammonium nitrate, wet phosphoric acid, complex fertilizers, etc.) (Kongshaug, 1998). In this work the exergy method is used to analyze the dependence of the primary energy ...

  20. Nitrogen stable isotopes of ammonium and nitrate in high mountain lakes of the Pyrenees

    OpenAIRE

    Bartrons, M.; Camarero, L.; Catalan, J

    2009-01-01

    Nitrogen stable isotopes (δ15N) are increasingly used to trace food web relationships and the flow of matter in lakes. However, there is high variability in δ15N among primary producers and other primary energy resources that can eventually propagate throughout the lake food web. To increase our understanding of the origin of this variability, we measured ammonium and nitrate δ15N in atmospheric...

  1. Evaluation of natural zeolite clinoptilolite efficiency for the removal of ammonium and nitrate from aquatic solutions

    OpenAIRE

    Mozhdeh Murkani; Mohammad Nasrollahi; Maryam Ravanbakhsh; Parvaneh Bahrami; Neamat Jaafarzadeh Haghighi Fard

    2015-01-01

    Background: Surface water and groundwater pollution with various forms of nitrogen such as ammonium and nitrate ions is one of the main environmental risks. The major objectives of this study were to evaluate the capacity of natural zeolite (clinoptilolite) to remove NO3– and NH4+ from polluted water under both batch and column conditions. Methods: The laboratory batch and column experiments were conducted to investigate the feasibility of clinoptilolite as the adsorbent for removal of nit...

  2. An Experimental Assesment of Changes to the Size Distribution of Ammonium Nitrate Under Isothermal Conditioning

    Czech Academy of Sciences Publication Activity Database

    Talbot, Nicholas; Ondráček, Jakub; Ždímal, Vladimír

    Praha : Czech Aerosol Society, 2013 - (Zíková, N.), s. 31-34 ISBN 978-80-86186-52-8. [Výroční konference České aerosolové společnosti /14./. Nový Smokovec, High Tatras (SK), 23.10.2013-25.10.2013] Institutional support: RVO:67985858 Keywords : ammonium nitrate * nitric acid * ammonia Subject RIV: CF - Physical ; Theoretical Chemistry

  3. Adaptation to osmotic stress provides protection against ammonium nitrate in Pelophylax perezi embryos

    OpenAIRE

    Ortíz-Santaliestra, Manuel E.; Fernández-Benéitez, María José; Lizana, Miguel; Marco, Adolfo

    2010-01-01

    The negative effects of pollution on amphibians are especially high when animals are additionally stressed by other environmental factors such as water salinity. However, the stress provoked by salinity may vary among populations because of adaptation processes. We tested the combined effect of a common fertilizer, ammonium nitrate (0–90.3 mg N–NO3NH4/L), and water salinity (0–2&) on embryos of two Pelophylax perezi populations from ponds with different salinity c...

  4. Density effects on ammonium nitrate toxicity on amphibians. Survival, growth and cannibalism

    OpenAIRE

    Ortíz-Santaliestra, Manuel E.; Fernández-Benéitez, María José; Marco, Adolfo

    2012-01-01

    Temporary ponds where many amphibians breed experience a gradual desiccation that leads to growing larval densities, which can reduce tadpole survival rates and increase cannibalistic interactions among carnivorous salamander larvae. Concentrations of many agrochemicals, including nitrogenous fertilizers, can also increase as the water volume decreases. We analyzed the effects of ammonium nitrate fertilizer at two larval densities on growth and survival of Rana dalmatina tadpoles, and on cann...

  5. Different species of basil need different ammonium to nitrate ratio in hydroponics' system

    Directory of Open Access Journals (Sweden)

    M. SAADATIAN

    2015-12-01

    Full Text Available Basil is a very important medicinal plant and culinary spice, and is marketed fresh, dried or frozen. In crop nutrition, nitrogen is essential for plant growth and as a macro-element, is part of the proteins’ structure and participates in the metabolic processes involved in the synthesis and energy transfer. It has been shown that a balance between ammonium and nitrate favors plant growth and that the degree of benefit varies among crops. This study was conducted to evaluate the growth of two varieties of basil in function of four nutrient solutions containing different NH4+/NO3- ratios. Results showed that different variety response differently to nutrient solution. Although the highest yield in both varieties (sweet and purple was obtained when fed by nutrient solution without ammonium but their response on quality indices were different due to nitrate ammonium ratio in nutrient solutions. The highest total phenol content of sweet and purple basil was 92 and 100 mg gallic acid equivalent per gram of dry weight respectively, while the highest antioxidant capacity was obtained in purple variety grown in nutrient solution 2 (NH4+:1/NO3:4 and the lowest value were related to sweet variety with the same nutrient solution. Moderate content of total nitrogen can be suitable for sweet variety while for purple variety nutrient solution with low amount of ammonium can be more suitable.

  6. NUMERICAL SIMULATION WITH A COMPREHENSIVE CHEMICAL TRANSPORT MODEL OF NITRATE, SULFATE, AND AMMONIUM AEROSOL DISTRIBUTIONS OVER EAST ASIA

    Institute of Scientific and Technical Information of China (English)

    Meigen Zhang

    2005-01-01

    The transport and chemical production processes of nitrate, sulfate, and ammonium aerosols over East Asia were investigated by use of the Models-3 Community Multi-scale Air Quality (CMAQ) modeling system coupled with the Regional Atmospheric Modeling System (RAMS). For the evaluation of the model's ability in depicting their3-dimensional concentration distributions and temporal variations, modeled concentrations of nitrate, sulfate, and ammonium aerosols are compared with the observations obtained at a ground station in Japan in March 2001 and onboard of an aircraft DC-8 on 18 and 21 March 2001 during the Transport and Chemical Evolution over the Pacific (TRACE-P)field campaign. Comparison shows that simulated values of nitrate, sulfate, and ammonium aerosols are generally in good agreement with their observed data, and the model captures most important observed features, and reproduces temporal and spatial variations of nitrate, sulfate, and ammonium aerosol concentrations reasonably well, e.g., the timing and locations of the concentration spikes of nitrate, sulfate, and ammonium aerosols are well reproduced, but large discrepancies between observed and simulated values are also clearly seen at some points and some times due to the coarse grid resolution and uncertainties of the emissions used in this study. This comparison results indicate that CMAQ is able to simulate the distributions of nitrate, sulfate, and ammonium aerosols and their related species in the troposphere over East Asia reasonably well.

  7. The ammonium nitrate particle equivalent of NOx emissions for wintertime conditions in Central California's San Joaquin Valley

    International Nuclear Information System (INIS)

    A new method has been developed to assess the aerosol particle formation reactivity of nitrogen oxide (NOx) emissions. The method involves using a photochemical box model with gas-phase photochemistry, aerosol production and deposition to calculate the ammonium nitrate particle equivalent of NOx emissions. The yields of ammonium nitrate particles used in the box model were determined from parametric simulations made with an equilibrium model that calculated the fraction of nitric acid that reacts to produce ammonium nitrate from the temperature, relative humidity and ammonium-to-nitrate ratios. For the wintertime conditions of emissions and meteorology in the San Joaquin Valley of central California, approximately 80% of the moles of nitric acid produced was found to be in the particulate nitrate phase and about 33% of the moles of emitted NOx was converted to particulate nitrate. The particle equivalent of NOx emissions was found to be on the order of 0.6 g of ammonium nitrate for each gram of NOx emitted (the mass of NOx calculated as NO2). This estimate is in reasonable agreement with an analysis of field measurements made in central California. (author)

  8. Terahertz spectroscopy and solid-state density functional theory simulations of the improvised explosive oxidizers potassium nitrate and ammonium nitrate.

    Science.gov (United States)

    Witko, Ewelina M; Buchanan, William D; Korter, Timothy M

    2011-11-10

    Terahertz spectroscopy provides a noninvasive and nondestructive method for detecting and identifying concealed explosives. In this work, the room-temperature and cryogenic terahertz spectra of two common improvised explosive oxidizers, namely, potassium nitrate (KN) and ammonium nitrate (AN), are presented, along with detailed solid-state density functional theory (DFT) analyses of the crystalline structures and spectral features. At both 294 and 78 K, KN exhibits two terahertz absorption features below 100 cm(-1) that have been assigned through DFT simulations to arise from hindered nitrate rotations in the KN-II crystalline polymorph. The terahertz spectrum of AN exhibits a pronounced temperature dependence. The 294 K spectrum is free of any absorptions, whereas the 78 K spectrum consists of several narrow and intense peaks. The origin of this large difference is the polymorphic transition that occurs during cooling of AN, where room-temperature AN-IV is converted to AN-V at 255 K. The 78 K terahertz spectrum of AN is assigned here to various ion rotations and translations in the AN-V polymorph lattice. The analysis of the room-temperature AN-IV terahertz spectrum proved to be more complicated. The solid-state DFT simulations predicted that the room-temperature crystal structure of AN is not very well described using the standard Pmmn space-group symmetry as previously believed. The AN-IV polymorph actually belongs to the Pmn2(1) space group, and the perceived Pmmn symmetry results from vibrational averaging through nitrate rotations. This newly observed Pmn2(1) crystal symmetry for room-temperature AN is the reason for the absence of absorption features in the 294 K terahertz spectrum of AN and provides new insight into the polymorphic transitions of this ionic solid. PMID:22007790

  9. Influence of dissolved oxygen conditions on toxicity of ammonium nitrate to larval natterjack toads.

    Science.gov (United States)

    Ortiz-Santaliestra, Manuel E; Marco, Adolfo

    2015-07-01

    Temporary ponds, where many amphibians from temperate regions breed, show an annual cycle with a maximum water volume in spring followed by a progressive desiccation throughout late spring and summer. This desiccation leads to a decrease in dissolved oxygen and an increase in nitrogen levels, which can additionally increase because of anthropogenic sources such as chemical fertilizers. We analyzed the toxicity posed by environmentally relevant levels of a common nitrogenous fertilizer, ammonium nitrate, at different conditions of oxygen availability to Bufo calamita tadpoles, which typically develop in ephemeral ponds. Ammonium nitrate (90.3 mg N-NO3NH4/l) and hypoxic conditions (initial dissolved oxygen 4.53 ± 0.40 mg/l) caused significant lethal effects after 7 and 12 days of exposure, respectively. At the end of experiment (16 days), mortality rates were 32.5 % in individuals exposed to the fertilizer and 15 % in those growing under hypoxic conditions. When both stressors were combined, they showed an additive effect on tadpole survival. Malformations, such as oedemas and spinal curvatures, and locomotory abnormalities, were detected after 12 days of experiment in >90 % of individuals exposed to 45.2 mg N-NO3NH4/l under hypoxic conditions, whereas none of these stressors by separate related to abnormality rates >35 %. Delayed development was also observed in tadpoles exposed to ammonium nitrate with hypoxia affecting developmental rate only after 12 days of exposure. The results are discussed in terms of potential mechanisms linking negative effects of both factors as well as in terms of potential alterations of the ecological plasticity that often allows amphibians to survive in unpredictable environments. PMID:25586169

  10. Accelerated leaching of cementitious materials using ammonium nitrate (6 M): influence of test conditions

    International Nuclear Information System (INIS)

    We have focused on the test conditions influence on accelerated degradation of cementitious materials using ammonium nitrate. PH-buffering and renewal of the leaching solution were studied. PH-buffering appeared not to be very important when the renewal pH remains under eight. Renewal appeared to be the most influential feature. Its absence leads to calcium accumulation in the leaching solution inducing aggressiveness fall. Degradation is then less marked in terms of depth, flux and mineralogy. The resulting porosity increase is also smaller. (authors)

  11. Identification and processing of hiding ammonium-nitrate explosives detecting signals

    International Nuclear Information System (INIS)

    This paper describes the study of identification and processing of hiding ammonium-nitrate explosives detecting signals in the safety inspection passages of airport, railway station etc. Restricting to the detecting conditions, the signals were faint, and the scattering backgrounds were high. According to this situation, spectrum shifted adding method was used to restrain the scattering background, at the same time peak area calculating method with strong ability of statistic fluctuation restraining were introduced, and the identification abilities of the system were improved notably. The explosives detection software based on Windows 95 was developed, and the key codes on initializing DMA controller in the hardware driver were listed

  12. Electron transfer reactions of 1-phenyl-4-vinylpyrazole mediated by cerium(IV) ammonium nitrate

    International Nuclear Information System (INIS)

    The title compound is converted into the cyclic ethers 5 and the alcohol 6 upon treatment with ceric ammonium nitrate in acetone. Using methanol as a solvent the dimethoxy derivative 9 and the nitrate ester 10 are formed. No cross cycloaddition is observed in the presence of olefins such as ethyl vinyl ether, DMAD, or indene; however, with cyclopentadiene as co-reagent a mixture of the exo-endo Diels-Alder adducts 14 involving the vinylic system of 1 as 2π component is obtained. The results are rationalized through the intermediacy of the radical cation 1.+, generated by single electron transfer (SET) from the neutral precursor 1 to Ce(IV)

  13. Polyethylene Glycols as Efficient Media for Decarboxylative Nitration of α,β-Unsaturated Aromatic Carboxylic Acids by Ceric Ammonium Nitrate in Acetonitrile Medium: A Kinetic and Mechanistic Study

    OpenAIRE

    K.Ramesh; S. Shylaja; K. C. Rajanna; P. Giridhar Reddy; P. K. Saiprakash

    2013-01-01

    Polyethylene glycols (PEGs) were found to be efficient media for decarboxylative nitration of α,β-unsaturated aromatic carboxylic acids by ceric ammonium nitrate (CAN) in acetonitrile to give β-nitrostyrene derivatives. Kinetics of the reaction exhibited second order kinetics with a first order dependence on [CAN] and [substrate]. Reactions were too sluggish to be studied in the absence of PEG; therefore detailed kinetics were not taken up. Reaction times were reduced from 24 hrs to few hours...

  14. Nitrogen concentrations in a small Mediterranean stream: 1. Nitrate 2. Ammonium

    Directory of Open Access Journals (Sweden)

    A. Butturini

    2002-01-01

    Full Text Available The importance of storm frequency as well as the groundwater and hyporheic inputs on nitrate (NO3-N and ammonium (NH4-N levels in stream water were studied in a small perennial Mediterranean catchment, Riera Major, in northeast Spain. NO3-N concentrations ranged from 0.15 to 1.9 mg l-1. Discharge explained 47% of the annual NO3-N concentration variance, but this percentage increased to 97% when single floods were analysed. The rate of change in nitrate concentration with respect to flow, ΔNO3-N/ΔQ, ranged widely from 0 to 20 μg NO3-N s l-2. The ΔNO3-N/ΔQ values fitted to a non linear model with respect to the storm flow magnitude (ΔQ (r2=0.48, d.f.=22, P3-N/ΔQ occurred at intermediate ΔQ values, whereas low ΔNO3-N/ΔQ values occurred during severe storms (ΔQ > 400 l s-1. N3-N concentrations exhibit anticlockwise hysteresis patterns with changing flow and the patterns observed for autumnal and winter storms indicated that groundwater was the main N3-N source for stream and hyporheic water. At baseflow, NO3-N concentration in groundwater was higher (t=4.75, d.f.=29, P>0.001 and co-varied with concentrations in the stream (r=0.91, d.f.=28, P3-N concentration in hyporheic water was identical to that in stream water. The role of the hyporheic zone as source or sink for ammonium was studied hyporheic was studied comparing its concentrations in stream and hyporheic zone before and after a major storm occurred in October 1994 that removed particulate organic matter stored in sediments. Results showed high ammonium concentrations (75±28 s.d. μg NH4-N l-1 before the storm flow in the hyporheic zone. After the storm, the ammonium concentration in the hyporheic dropped by 80% (13.6±8 μg N4-N l-1 and approached to the level found in stream water (11±8 μg NH4-N l-1 indicating that indisturbed hyporheic sediments act as a source for ammonium. After the storm, the ammonium concentrations in the stream, hyporheic and groundwater zones were very

  15. Reactive atomistic simulations of shock-induced initiation processes in mixtures of ammonium nitrate and fuel oil

    International Nuclear Information System (INIS)

    Ammonium nitrate mixed with fuel oil (ANFO) is a commonly used blasting agent. In this paper we investigated the shock properties of pure ammonium nitrate (AN) and two different mixtures of ammonium nitrate and n-dodecane by characterizing their Hugoniot states. We simulated shock compression of pure AN and ANFO mixtures using the Multi-scale Shock Technique, and observed differences in chemical reaction. We also performed a large-scale explicit sub-threshold shock of AN crystal with a 10 nm void filled with 4.4 wt% of n-dodecane. We observed the formation of hotspots and enhanced reactivity at the interface region between AN and n-dodecane molecules.

  16. Sources of nitrate and ammonium contamination in groundwater under developing Asian megacities

    International Nuclear Information System (INIS)

    The status of nitrate (NO3-), nitrite (NO2-) and ammonium (NH4+) contamination in the water systems, and the mechanisms controlling their sources, pathways, and distributions were investigated for the Southeast Asian cities of Metro Manila, Bangkok, and Jakarta. GIS-based monitoring and dual isotope approach (nitrate δ15N and δ18O) suggested that human waste via severe sewer leakage was the major source of nutrient contaminants in Metro Manila and Jakarta urban areas. Furthermore, the characteristics of the nutrient contamination differed depending on the agricultural land use pattern in the suburban areas: high nitrate contamination was observed in Jakarta (dry fields), and relatively lower nutrients consisting mainly of ammonium were detected in Bangkok (paddy fields). The exponential increase in NO3--δ15N along with the NO3- reduction and clear δ18O/δ15N slopes of NO3- (∼ 0.5) indicated the occurrence of denitrification. An anoxic subsurface system associated with the natural geological setting (e.g., the old tidal plain at Bangkok) and artificial pavement coverage served to buffer NO3- contamination via active denitrification and reduced nitrification. Our results showed that NO3- and NH4+ contamination of the aquifers in Metro Manila, Bangkok, and Jakarta was not excessive, suggesting low risk of drinking groundwater to human health, at present. However, the increased nitrogen load and increased per capita gross domestic product (GDP) in these developing cities may increase this contamination in the very near future. Continuous monitoring and management of the groundwater system is needed to minimize groundwater pollution in these areas, and this information should be shared among adjacent countries with similar geographic and cultural settings

  17. Stripping study of U(IV) from loaded TBP/n-paraffin using ammonium nitrate as a strippant

    International Nuclear Information System (INIS)

    With the increase in uranium loading in the organic, there was an increase in % stripping of uranium for ammonium nitrate whereas for distilled water it became reversed. With the increase of pH of the aqueous ammonium nitrate solution, it was found that stripping increased up to a pH of 8.5 and after that precipitation starts. Increase in temperature of the biphasic system shows an enhancing effect of uranium stripping. Evaluation of thermodynamic data like ΔH and ΔS indicated that the process is endothermic. Equilibrium isotherms at various operating conditions were generated for both water and ammonium nitrate. Based on the optimized conditions, Mc-Cabe Thiele diagrams were constructed using ammonium nitrate (50 g/L) of pH 7.5 at room temperature. Result showed that at an O/A ratio of 2/5, at least 7 theoretical countercurrent stages are needed at room temperature with an initial uranium loading of 115.4 g/L to get 40 g/L of uranyl nitrate pure solution in the rich end leaving only 3 g/L uranium in the lean solvent whereas for water to strip all the uranium (from 100 g/L) requires only 4 numbers of countercurrent stages at an O/A ratio of 2/3 at room temperature

  18. [Achievement of Sulfate-Reducing Anaerobic Ammonium Oxidation Reactor Started with Nitrate-Reducting Anaerobic Ammonium Oxidation].

    Science.gov (United States)

    Liu, Zheng-chuan; Yuan, Lin-jiang; Zhou, Guo-biao; Li, Jing

    2015-09-01

    The transformation of nitrite-reducing anaerobic ammonium oxidation to sulfate-reducing anaerobic ammonium oxidation in an UASB was performed and the changes in microbial community were studied. The result showed that the sulfate reducing anaerobic ammonium oxidation process was successfully accomplished after 177 days' operation. The removal rate of ammonium nitrogen and sulfate were up to 58. 9% and 15. 7%, the removing load of ammonium nitrogen and sulfate were 74. 3 mg.(L.d)-1 and 77. 5 mg.(L.d)-1 while concentration of ammonium nitrogen and sulfate of influent were 130 mg.(L.d)-1 and 500 mg.(L.d)-1, respectively. The lost nitrogen and sulphur was around 2 in molar ratio. The pH value of the effluent was lower than that of the influent. Instead of Candidatus brocadia in nitrite reducing anaerobic ammonium oxidation granular sludge, Bacillus benzoevorans became the dominant species in sulfate reducing anaerobic ammonium oxidation sludge. The dominant bacterium in the two kinds of anaerobic ammonium oxidation process is different. Our results imply that the two anaerobic ammonium oxidation processes are carried out by different kind of bacterium. PMID:26717697

  19. Evidence for dissimilatory reduction of nitrate to ammonium in irradiated soil

    International Nuclear Information System (INIS)

    The influence of gamma irradiation (1 kGy) on nitrogen transformation in a brown soil, labelled with 15N(Ca(NO3)2) and glucose amended was studied. The fractions of the added nitrique-N in the ammoniacal-N, organic-N and N-gas forms were determined. In the unirradiated soil, after 3 days incubation, 54% of the N transformations from N-nitrique was accounted for by organization and 45% was lost by denitrification. In the irradiated soil, these transformations were less intense, but the production of ammonium by the dissimilatory nitrate reduction was noticeable (25% of the N-NO3- transformation). Two hypothesis are discussed: one on microbial dynamic population and the other, on the factors affecting this process

  20. Development of a microbiological ammonium to nitrate recycling bioreactor for space capsules

    International Nuclear Information System (INIS)

    Since 1988, the Expertise group of Molecular and Cellular Biology (MCB) is an important partner in the development of the Micro-Ecological Life Support System Alternative (MELiSSA). The MELiSSA was designed to allow a small crew to survive on an Antarctic, lunar or Mars outpost, and is a joint research project currently fostered by the European Space Agency, ESA. The MELiSSA functions through a series of five interconnected compartments, of which four are microbial bioreactors and was engineered to degrade organic waste, regenerate the outpost's atmosphere and water, and provide the crew with an additional vegetarian diet. The bioreactor of the third compartment provides the edible cyanobacteria and plants of the fourth compartment with nitrate instead of ammonium as a source of nitrogen. The two bacteria responsible for the biological transformation of ammonium to nitrate (nitrification) are Nitrosomonas europaea and Nitrobacter winogradskyi. Since all MELiSSA-reactors are to be relied on for a period of several years, reactor operation is to be studied exhaustively to allow optimal process- and reactor performance. Therefore, a pilot reactor for the third compartment was engineered and constructed at the Universitat Autonoma de Barcelona (UAB), where the pilot plant of the MELiSSA is installed. The reactor was able to perform nitrification with high efficiency for the entire trial period of nearly five years and was the subject of this study. Collaboration between the unit of MCB and researchers at Universitat Autonoma de Barcelona (UAB) allowed the development and validation of a mathematical model for the third compartment of the MELiSSA. A mathematical model will allow optimizing reactor operation and reactor performance even further. A Real-Time Quantitative Polymerase Chain Reaction (Q-PCR) was developed at MCB that allowed the quantitative assessment of the relative distribution of the two autotrophic nitrifying bacterial species along the reactor's packed

  1. Assessment of the importance of dissimilatory nitrate reduction to ammonium for the terrestrial nitrogen cycle

    Science.gov (United States)

    Rütting, T.; Boeckx, P.; Müller, C.; Klemedtsson, L.

    2011-07-01

    The nitrogen (N) cycle contains two different processes of dissimilatory nitrate (NO3-) reduction, denitrification and dissimilatory NO3- reduction to ammonium (DNRA). While there is general agreement that the denitrification process takes place in many soils, the occurrence and importance of DNRA is generally not considered. Two approaches have been used to investigate DNRA in soil, (1) microbiological techniques to identify soil microorganisms capable of DNRA and (2) 15N tracing to elucidate the occurrence of DNRA and to quantify gross DNRA rates. There is evidence that many soil bacteria and fungi have the ability to perform DNRA. Redox status and C/NO3- ratio have been identified as the most important factors regulating DNRA in soil. 15N tracing studies have shown that gross DNRA rates can be a significant or even a dominant NO3- consumption process in some ecosystems. Moreover, a link between heterotrophic nitrification and DNRA provides an alternative pathway of ammonium (NH4+) production to mineralisation. Numerical 15N tracing models are particularly useful when investigating DNRA in the context of other N cycling processes. The results of correlation and regression analyses show that highest gross DNRA rates can be expected in soils with high organic matter content in humid regions, while its relative importance is higher in temperate climates. With this review we summarise the importance and current knowledge of this often overlooked NO3- consumption process within the terrestrial N cycle. We strongly encourage considering DNRA as a relevant process in future soil N cycling investigations.

  2. Dissimilatory nitrate reduction to ammonium conserves nitrogen in anthropogenically affected subtropical mangrove sediments in Southeast China.

    Science.gov (United States)

    Cao, Wenzhi; Yang, Jingxin; Li, Ying; Liu, Baoli; Wang, Feifei; Chang, Changtang

    2016-09-15

    In this study, basic sediment properties, nutrient flux, and nitrogen cycle (including denitrification, anaerobic ammonium oxidation [anammox], nitrification, and dissimilatory nitrate reduction to ammonium [DNRA]) were investigated at two sampling sites with different tree ages in the mangrove region of the Jiulong River Estuary, China. The results show that sediments at mangrove flat area have relatively strong capability to reduce NO3(-), in which the DNRA rate is relatively high (204.53±48.32μmolNm(-2)h(-1)), which is approximately 75.7-85.9% of the total NO3(-) reduction, while the denitrification and anammox rates are relatively low - only approximately 5.6-9.5% and 8.5-14.8% of the total NO3(-) reduction, respectively. Thus, in the nitrogen-enriched subtropical mangrove system, DNRA is the main pathway to reduce NO3(-), and most of the input nitrogen is conserved as NH4(+) in the system, which assures high productivity of the mangrove system. PMID:27368926

  3. Composition of the outermost layer and concentration depth profiles of ammonium nitrate ionic liquid surfaces.

    Science.gov (United States)

    Ridings, Christiaan; Warr, Gregory G; Andersson, Gunther G

    2012-12-14

    Differences in the surface structure of protic ionic liquids (ILs) with three different cations and a common anion; ethyl-, propyl- and 2-hydroxyethyl- (or ethanol-) ammonium nitrate (EAN, PAN and EtAN, respectively) have been observed by neutral impact collision ion scattering spectroscopy (NICISS) and metastable induced electron spectroscopy/ultraviolet photoelectron spectroscopy (MIES/UPS). NICISS is used to determine the concentration depth profiles of the elements in each IL and it reveals an enrichment of cation alkyl chains of PAN and EtAN in the outermost layer compared to EAN, and a corresponding depletion of nitrate from the outermost layer of the EtAN surface. MIES probes the molecular orbitals of only the species in the outermost layer of a sample and confirms that, while both the anion and the cation are present to some degree at the surface of all three ILs, the cation is enriched to a greater extent at the surface of PAN and EtAN compared to EAN. PMID:23103987

  4. Thermal decomposition of ammonium diuranate, uranyl nitrate hexahydrate and uranyl peroxide

    International Nuclear Information System (INIS)

    The behaviors of three types of starting powder had been investigated during their thermal decomposition processes in nitrogen, air, and hydrogen. The powder types were the products of uranyl nitrate precipitation, i.e. ADU (ammonium diuranate), UNH (uranyl nitrate hexahydrate), and UPO (uranyl peroxide). The objective of the investigation was to find out the best atmosphere that would result in good quality powder in a thermal decomposition process with the lowest temperature and the shortest period of time in order to reduce the cost of UO2 powder preparation. Before the thermal decomposition process was initiated, all powder types were characterized for their crystal structures. The investigation was conducted by TG-DTA instrument at temperature up to 800°C and the heating rate of 10°C/minute. The crystal structures were identified by X-Ray Diffractometer with Cu-Ka radiation. The specific surface area of the powder was also observed using BET method, especially for the powder that underwent the process in hydrogen heated up to 800°C. The Results showed that the process took place faster in hydrogen, and UNH required lower thermal decomposition temperature in relations with other types of powder. (author)

  5. Effects of the physical state of tropospheric ammonium-sulfate-nitrate particles on global aerosol direct radiative forcing

    Directory of Open Access Journals (Sweden)

    S. T. Martin

    2004-01-01

    Full Text Available The effect of aqueous versus crystalline sulfate-nitrate-ammonium tropospheric particles on global aerosol direct radiative forcing is assessed. A global three-dimensional chemical transport model predicts sulfate, nitrate, and ammonium aerosol mass. An aerosol thermodynamics model is called twice, once for the upper side (US and once for lower side (LS of the hysteresis loop of particle phase. On the LS, the sulfate mass budget is 40% solid ammonium sulfate, 12% letovicite, 11% ammonium bisulfate, and 37% aqueous. The LS nitrate mass budget is 26% solid ammonium nitrate, 7% aqueous, and 67% gas-phase nitric acid release due to increased volatility upon crystallization. The LS ammonium budget is 45% solid ammonium sulfate, 10% letovicite, 6% ammonium bisulfate, 4% ammonium nitrate, 7% ammonia release due to increased volatility, and 28% aqueous. LS aerosol water mass partitions as 22% effloresced to the gas-phase and 78% remaining as aerosol mass. The predicted US/LS global fields of aerosol mass are employed in a Mie scattering model to generate global US/LS aerosol optical properties, including scattering efficiency, single scattering albedo, and asymmetry parameter. Global annual average LS optical depth and mass scattering efficiency are, respectively, 0.023 and 10.7 m2 (g SO4-2-1, which compare to US values of 0.030 and 13.9 m2 (g SO4-2-1. Radiative transport is computed, first for a base case having no aerosol and then for the two global fields corresponding to the US and LS of the hysteresis loop. Regional, global, seasonal, and annual averages of top-of-the-atmosphere aerosol radiative forcing on the LS and US (FL and FU, respectively, in W m-2 are calculated. Including both anthropogenic and natural emissions, we obtain global annual averages of FL=-0.750, FU=-0.930, and DFU,L=24% for full sky calculations without clouds and FL=-0.485, FU=-0.605, and DFU,L=25% when clouds are included. Regionally, DFU,L=48% over the USA, 55% over Europe

  6. Comparative study of ammonium and nitrate fertilizers in two soils of Mauritius cropped with sugar-cane

    International Nuclear Information System (INIS)

    The fate of ammonium and nitrate fertilizers in stony and free soils of Mauritius cropped with sugar-cane is being studied in lysimeters placed under low and high rainfall regimes. The results obtained to date indicate that nitrogen moves from the soil into the groundwater mainly in the form of nitrate and that the movement is more pronounced when nitrate fertilizers are used in preference to their ammonium counterparts. The loss of nitrogen by leaching increases with intensity of rainfall but is hindered by an increasingly clayey texture and high cation exchange capacity of the soil. The mobility of the applied nitrogen governs its efficiency of utilization by sugar-cane. While the mobile nitrate is more efficient than ammonium in low-rainfall areas, the opposite is true in the superhumid zones. The recovery of nitrogen by sugar-cane is thus influenced by rainfall, soil properties and the chemical forms of the applied nitrogen. This study also provides circumstantial evidence to the effect that high concentration of nitrate in the natural waters of Mauritius is caused by the low efficiency of nitrogen utilization in soils of a superhumid zone. (author)

  7. Influence of organic carbon and nitrate loading on partitioning between dissimilatory nitrate reduction to ammonium (DNRA) and N2 production

    Science.gov (United States)

    Hardison, Amber K.; Algar, Christopher K.; Giblin, Anne E.; Rich, Jeremy J.

    2015-09-01

    Biologically available nitrogen is removed from ecosystems through the microbial processes of anaerobic ammonium oxidation (anammox) or denitrification, while dissimilatory nitrate reduction to ammonium (DNRA) retains it. A mechanistic understanding of controls on partitioning among these pathways is currently lacking. The objective of this study was to conduct a manipulative experiment to determine the influence of organic C and NO3- loading on partitioning. Sediment was collected from a location on the southern New England shelf (78 m water depth) and sieved. Half of the sediment was mixed with freeze-dried phytoplankton and the other half was not. Sediment was then spread into 1.5 mm, "thin discs" closed at the bottom and placed in large aquarium tanks with filtered, N2/CO2 sparged seawater to maintain O2 limited conditions. Half of the discs received high NO3- loading, while the other half received low NO3- loading, resulting in a multifactorial design with four treatments: no C addition, low NO3- (-C-N); C addition, low NO3- (+C-N); no C addition, high NO3- (-C+N); and C addition, high NO3- (+C+N). Sediment discs were incubated in the tanks for 7 weeks, during which time inorganic N (NH4+, NO3-, and NO2-) was monitored, and sediment discs were periodically removed from the tanks to conduct 15N isotope labeling experiments in vials to measure potential rates of anammox, denitrification, and DNRA. Temporal dynamics of inorganic N concentrations in the tanks were indicative of anoxic N metabolism, with strong response of the build up or consumption of the intermediate NO2-, depending on treatments. Vial incubation experiments with added 15NO2- + 14NH4+ indicated significant denitrification and DNRA activity in sediment thin discs, but incubations with added 15NH4+ + 14NO2- indicated anammox was not at all significant. Inorganic N concentrations in the tanks were fit to a reactive transport model assuming different N transformations. Organic C decomposition rates

  8. Assessing the ammonium nitrate formation regime in the Paris megacity and its representation in the CHIMERE model

    Science.gov (United States)

    Petetin, Hervé; Sciare, Jean; Beekmann, Matthias; Sanchez, Olivier; Rosso, Amandine; Denier van der Gon, Hugo

    2014-05-01

    Ammonium nitrates significantly contribute to the fine particulate matter load, in particular in the Paris agglomeration where two measurement campaigns, PARTICULES and FRANCIPOL, have recently made available a large database on this compound and its gaseous precursors, nitric acid and ammonia. These new observations give the opportunity (for the first time in France) to assess the ammonium nitrate formation regime (in terms of limited species) as well as the ability of the CHIMERE chemistry-transport model to simulate each species and to reproduce in fine the observed regime. Quite satisfactory results are obtained on nitrates, mainly due to a significant contribution of imports from outside the agglomeration. However, significant biases affect both gaseous precursors. Various uncertainty sources are discussed, including those relative to ammonia trafic and agricultural emissions, thermodynamic equilibria or oxidative capacity of the atmosphere. Despite these errors, CHIMERE manages to simulate a HNO3-limited regime, in agreement with observations, at least at the daily scale. This study especially confirms that further work on the OH radical characterization in the CHIMERE model and agricultural ammonia emissions are required to improve the simulation of the ammonium nitrate formation regime.

  9. Denitrification and Nitrate Reduction to Ammonium in Taihu Lake and Yellow sea Inter—Tidal Marine Sediments

    Institute of Scientific and Technical Information of China (English)

    YINSHIXUE; SHENQIRONG; 等

    1999-01-01

    Denitrification and nitrate reduction to ammonium in Taihu Lake and Yellow Sea inter-tidal marine sediments were studied.The sediment samples were made slurry containing 150g dry matter per liter.Various of glucose-C to nitrate-N.Acetylene inhibition technique was applied to measure denitrification in the slurres,All samples were incubated anaerobically under argon atmosphere,Data showed that Taihu Lake sediment produced more N2O than marine sediment,Denitrification potential was higher in Taihu Lake sediment than in marine one,Glucose added increase denitrification activity but not the denitrification potential of the sediments.Dissimilatory nitrate reduction to ammonium seemed to occur in marine sediment,but not in freshwater one.When the marine sediment was treated with 25mmol L-1 glucose,its denitrification potentail,as indicated by maximum N2O production by acetylene blockage,was lower than that treated with no or 2.5mmol L-1 glucose.Acetylene was suspected to have inhibitory effect on dissimilatory nitrate reduction to ammonium.

  10. Nitrogen stable isotopes of ammonium and nitrate in high mountain lakes of the Pyrenees

    Directory of Open Access Journals (Sweden)

    M. Bartrons

    2009-12-01

    Full Text Available Nitrogen stable isotopes (δ15N are increasingly used to trace food web relationships and the flow of matter in lakes. However, there is high variability in δ15N among primary producers and other primary energy resources that can eventually propagate throughout the lake food web. To increase our understanding of the origin of this variability, we measured ammonium and nitrate δ15N in atmospheric deposition (AD, epilimnetic water (EW, deep chlorophyll maximum water (DCMW, and sediment porewater (SPW in eight mountain lakes. A general δ15N (−3.4‰ for AD was estimated as the signature for AD ammonium and nitrate did not differ. All lakes showed similar high δ15N-NH4+ values for SPW (ca. 2.2‰. In contrast, the variability among lakes in water column values was high, although differences between EW and DCMW within a lake were low. δ15N-NO3- correlated with the altitude of the lakes, and its variability was interpreted as the influence of catchment nitrification, which is higher in talus landscapes. δ15N-NH4+ distribution had two modes, positive values (ca. 3‰ were associated to DCMW of shallow lakes, and probably reflect the SPW influence. Lower values (ca. −3‰ occur in EW and DCMW of deep lakes, and its variability was related to the degree that NO3- was up taken by primary producers and recycled within the food-web when NH4+ availability was low compared to demand. Overall, altitude, lake depth and seasonal cumulative primary production largely explain the patterns of δ15N variability observed in nitrogen dissolved compounds.

  11. On the effectiveness of nitrogen oxide reductions as a control over ammonium nitrate aerosol

    Science.gov (United States)

    Pusede, S. E.; Duffey, K. C.; Shusterman, A. A.; Saleh, A.; Laughner, J. L.; Wooldridge, P. J.; Zhang, Q.; Parworth, C. L.; Kim, H.; Capps, S. L.; Valin, L. C.; Cappa, C. D.; Fried, A.; Walega, J.; Nowak, J. B.; Weinheimer, A. J.; Hoff, R. M.; Berkoff, T. A.; Beyersdorf, A. J.; Olson, J.; Crawford, J. H.; Cohen, R. C.

    2016-03-01

    Nitrogen oxides (NOx) have fallen steadily across the US over the last 15 years. At the same time, NOx concentrations decrease on weekends relative to weekdays, largely without co-occurring changes in other gas-phase emissions, due to patterns of diesel truck activities. These trends taken together provide two independent constraints on the role of NOx in the nonlinear chemistry of atmospheric oxidation. In this context, we interpret interannual trends in wintertime ammonium nitrate (NH4NO3) in the San Joaquin Valley of California, a location with the worst aerosol pollution in the US and where a large portion of aerosol mass is NH4NO3. Here, we show that NOx reductions have simultaneously decreased nighttime and increased daytime NH4NO3 production over the last decade. We find a substantial decrease in NH4NO3 since 2000 and conclude that this decrease is due to reduced nitrate radical-initiated production at night in residual layers that are decoupled from fresh emissions at the surface. Further reductions in NOx are imminent in California, and nationwide, and we make a quantitative prediction of the response of NH4NO3. We show that the combination of rapid chemical production and efficient NH4NO3 loss via deposition of gas-phase nitric acid implies that high aerosol days in cities in the San Joaquin Valley air basin are responsive to local changes in NOx within those individual cities. Our calculations indicate that large decreases in NOx in the future will not only lower wintertime NH4NO3 concentrations but also cause a transition in the dominant NH4NO3 source from nighttime to daytime chemistry.

  12. On the effectiveness of nitrogen oxide reductions as a control over ammonium nitrate aerosol

    Directory of Open Access Journals (Sweden)

    S. E. Pusede

    2015-10-01

    Full Text Available Nitrogen oxides (NOx have fallen steadily across the US over the last fifteen years. At the same time, due to patterns diesel truck activities, NOx concentrations decrease on weekends relative to weekdays, largely without co-occurring changes in other gas-phase emissions. These trends taken together provide two independent constraints on the role of NOx in the nonlinear chemistry of atmospheric oxidation. In this context, we interpret interannual trends in wintertime ammonium nitrate (NH4NO3 in the San Joaquin Valley of California, a location with the worst aerosol pollution in the US and where a large portion of aerosol mass is NH4NO3. Here, we show that NOx reductions have simultaneously decreased nighttime and increased daytime NH4NO3 production over the last decade. We find a substantial decrease in NH4NO3 since 2000 and conclude that this decrease is due to reduced nitrate radical-initiated production at night in residual layers that are decoupled from fresh emissions at the surface. Further reductions in NOx are imminent in California, and nationwide, and we make a quantitative prediction of the response of NH4NO3. We show that the combination of rapid chemical production and efficient NH4NO3 loss via deposition of gas-phase nitric acid implies high aerosol days in cities in the San Joaquin Valley air basin are responsive to local changes in NOx within those individual cities. Our calculations indicate that large decreases in NOx in the future will not only lower wintertime NH4NO3 concentrations, they will also cause a transition in the dominant NH4NO3 source from nighttime to daytime chemistry.

  13. Nitrate and Ammonium Contribute to the Distinct Nitrogen Metabolism of Populus simonii during Moderate Salt Stress.

    Directory of Open Access Journals (Sweden)

    Sen Meng

    Full Text Available Soil salinity is a major abiotic stressor affecting plant growth. Salinity affects nitrification and ammonification in the soil, however, limited information is available on the influence of different N sources on N metabolism during salt stress. To understand the N metabolism changes in response to different N sources during moderate salt stress, we investigated N uptake, assimilation and the transcript abundance of associated genes in Populus simonii seedlings treated with moderate salt stress (75mM NaCl under hydroponic culture conditions with nitrate (NO3- or ammonium (NH4+. Salt stress negatively affected plant growth in both NH4+-fed and NO3--fed plants. Both NH4+ uptake and the total N concentration were significantly increased in the roots of the NH4+-fed plants during salt stress. However, the NO3- uptake and nitrate reductase (NR and nitrite reductase (NiR activity primarily depended on the NO3- supply and was not influenced by salt stress. Salt stress decreased glutamine synthetase (GS and glutamate synthase (GOGAT activity in the roots and leaves. Most genes associated with NO3-uptake, reduction and N metabolism were down-regulated or remained unchanged; while two NH4+ transporter genes closely associated with NH4+ uptake (AMT1;2 and AMT1;6 were up-regulated in response to salt stress in the NH4+-fed plants. The accumulation of different amino acid compounds was observed in the NH4+- and NO3-- fed plants during salt treatment. The results suggested that N metabolism in P. simonii plants exposed to salt enhanced salt resistance in the plants that were fed with NO3- instead of NH4+ as the sole N source.

  14. Short-term physiological responses of mosses to atmospheric ammonium and nitrate

    Energy Technology Data Exchange (ETDEWEB)

    Soares, A.; Pearson, J. [University College London, London (United Kingdom). Dept. of Biology

    1997-01-01

    Many bryophytes rely to a large extent on atmospheric deposition for their nutrient uptake. However, increasing levels of atmospheric ammonium (NH{sub 4}{sup +}) and nitrate (NO{sub 3}{sup -}) attract concern as to the possible harmful effects on bryophytes from these two nutrient sources. Changes in nitrate reductase (NR) activities, cation (Ca, K and Mg), total nitrogen (N) and organic acid concentrations were investigated for the mosses, Racomitrium lanuginosum, Rytidiadelphus loreus and Philonotis fontana, in response to a single field misting with 3 mol m{sup -3}NH{sub 4}{sup +} and NO{sub 3}{sup -}. Increases of 20% were recorded for tissue N content, 48hr after misting with 3 mol m{sup -3} NH{sub 4}{sup +} and NO{sub 3}{sup -. Increase labelled {sup 15}NH{sub 4}sup +} or {sup 15}NO{sub 3}{sup -} were applied to R. Lanuginosum at 1, 3 and 6 mol m{sup -3} concentrations, partitioning of incorporated {sup 15}N between different tissue regions occurred, with the highest N uptake in the upper stem and leaves. High concentrations of applied N resulted in reduced efficiency of N uptake. NH{sup 4}{sup +} applications caused declines in NR activities, organic acids and cations, whereas, NO{sub 3}{sup -} treatments caused the reverse response. Changes in cation contents, organic acids and NR activity reflect short-term regulation of N metabolism in the presence of defined N sources, as well as potential mechanisms of regulating cell pH homoeostasis. The consistency of physiological responses, especially NR activities, over short-term pollution episodes, provides evidence for their use as indicators of both NH{sub 4}{sup +} and NO{sub 3}{sup -} pollution. 41 refs., 7 figs., 1 tab.

  15. The analysis of 15N/14N ratios in natural samples, with emphasis on nitrate and ammonium in precipitation

    International Nuclear Information System (INIS)

    The nitrogen cycle is one of the most important of the earth's elemental cycles. The report describes the procedures used for the analysis of 15N/14N ratios in ammonium and nitrate (and organic nitrogen), and summaries without discussion the data obtained for precipitation (by rain and dust) collected at the Council for Scientific and Industrial Research site. The 15N/14N ratios of nitrogen compounds were determined on N2 gas. This was measured by means of a mass spectrometer. The isotopic analysis of organic nitrogen were conducted in two ways: Kjeldahl digestion to form ammonium, and Dumas combustion directly to N2

  16. Dissimilatory nitrogen reduction in intertidal sediments of a temperate estuary: small scale heterogeneity and novel nitrate-to-ammonium reducers.

    Science.gov (United States)

    Decleyre, Helen; Heylen, Kim; Van Colen, Carl; Willems, Anne

    2015-01-01

    The estuarine nitrogen cycle can be substantially altered due to anthropogenic activities resulting in increased amounts of inorganic nitrogen (mainly nitrate). In the past, denitrification was considered to be the main ecosystem process removing reactive nitrogen from the estuarine ecosystem. However, recent reports on the contribution of dissimilatory nitrate reduction to ammonium (DNRA) to nitrogen removal in these systems indicated a similar or higher importance, although the ratio between both processes remains ambiguous. Compared to denitrification, DNRA has been underexplored for the last decades and the key organisms carrying out the process in marine environments are largely unknown. Hence, as a first step to better understand the interplay between denitrification, DNRA and reduction of nitrate to nitrite in estuarine sediments, nitrogen reduction potentials were determined in sediments of the Paulina polder mudflat (Westerschelde estuary). We observed high variability in dominant nitrogen removing processes over a short distance (1.6 m), with nitrous oxide, ammonium and nitrite production rates differing significantly between all sampling sites. Denitrification occurred at all sites, DNRA was either the dominant process (two out of five sites) or absent, while nitrate reduction to nitrite was observed in most sites but never dominant. In addition, novel nitrate-to-ammonium reducers assigned to Thalassospira, Celeribacter, and Halomonas, for which DNRA was thus far unreported, were isolated, with DNRA phenotype reconfirmed through nrfA gene amplification. This study demonstrates high small scale heterogeneity among dissimilatory nitrate reduction processes in estuarine sediments and provides novel marine DNRA organisms that represent valuable alternatives to the current model organisms. PMID:26528270

  17. Dissimilatory nitrogen reduction in intertidal sediments of a temperate estuary: small scale heterogeneity and novel nitrate-to-ammonium reducers.

    Directory of Open Access Journals (Sweden)

    Helen eDecleyre

    2015-10-01

    Full Text Available The estuarine nitrogen cycle can be substantially altered due to anthropogenic activities resulting in increased amounts of inorganic nitrogen (mainly nitrate. In the past, denitrification was considered to be the main ecosystem process removing reactive nitrogen from the estuarine ecosystem. However, recent reports on the contribution of dissimilatory nitrate reduction to ammonium (DNRA to nitrogen removal in these systems indicated a similar or higher importance, although the ratio between both processes remains ambiguous. Compared to denitrification, DNRA has been underexplored for the last decades and the key organisms carrying out the process in marine environments are largely unknown. Hence, as a first step to better understand the interplay between denitrification, DNRA and reduction of nitrate to nitrite in estuarine sediments, nitrogen reduction potentials were determined in sediments of the Paulina polder mudflat (Westerschelde estuary. We observed high variability in dominant nitrogen removing processes over a short distance (1.6 m, with nitrous oxide, ammonium and nitrite production rates differing significantly between all sampling sites. Denitrification occurred at all sites, DNRA was either the dominant process (two out of five sites or absent, while nitrate reduction to nitrite was observed in most sites but never dominant. In addition, novel nitrate-to-ammonium reducers assigned to Thalassospira, Celeribacter and Halomonas, for which DNRA was thus far unreported, were isolated, with DNRA phenotype reconfirmed through nrfA gene amplification. This study demonstrates high small scale heterogeneity among dissimilatory nitrate reduction processes in estuarine sediments and provides novel marine DNRA organisms that represent valuable alternatives to the current model organisms.

  18. AN ECONOMICAL AND ECOFRIENDLY REGIOSELECTIVE BROMINATION OF ACETANILIDES USING POTASSIUM BROMIDE AND CERIC AMMONIUM NITRATE IN POLYETHYLENE GLYCOL Eine wirtschaftliche und umweltfreundliche regioselektive Bromierung von Acetanilide unter Verwendung von Kaliumbromid UND CERIC AMMONIUM NITRATE in Polyethylenglykol

    Directory of Open Access Journals (Sweden)

    Ritu Gupta and Lata

    2012-07-01

    Full Text Available A fast, economically, eco-friendly and highly chemo-regioselective method for the bromination of electron rich aromatic molecules has been developed by electrophilic substitution of Br+, which is generated in situ from KBr using ceric ammonium nitrate as the lewis acid catalyst in PEG-400 and the products are produced in highly excellent isolated yields and crude products do not require any further purification. Free aromatic amines remained unaffected under the reaction conditions.

  19. Ammonium and nitrate in soil and upland rice yield as affected by cover crops and their desiccation time

    Directory of Open Access Journals (Sweden)

    Adriano Stephan Nascente

    2012-12-01

    Full Text Available The objective of this work was to evaluate the effect of cover crops and their desiccation times on upland rice yield and on the levels of nitrate and ammonium in a no-tillage soil. The experiment was carried out in a randomized blocks, with split plots and three replicates. Cover crops (plots were sowed in the off-season (March 2009. In November 2009, at 30, 20, 10 and 0 days before rice sowing (split plots, herbicide was applied on the cover crops (fallow, Panicum maximum, Urochloa ruziziensis, U. brizantha and millet. Straw and soil were sampled (0 - 10 cm at the sowing day, and after 7, 14, 21, 28 and 35 days. Straws from millet and fallow were degraded more rapidly and provided the lowest level of nitrate in the soil. Urochloa ruziziensis, U. brizantha and P. maximum produced higher amounts of dry matter, and provided the highest levels of nitrate in the soil. Millet provides the lowest nitrate/ammonium ratio and the highest upland rice yield. Desiccations carried out at 30 and 20 days before sowing had the largest levels of nitrate in the soil at the sowing date. Nitrogen content and forms in the soil are affected by cover crops and their desiccation times.

  20. Simulation of detonation of ammonium nitrate fuel oil mixture confined by aluminum: edge angles for DSD

    Energy Technology Data Exchange (ETDEWEB)

    Short, Mark [Los Alamos National Laboratory; Quirk, James J [Los Alamos National Laboratory; Kiyanda, Charles B [Los Alamos National Laboratory; Jackson, Scott I [Los Alamos National Laboratory; Briggs, Matthew E [Los Alamos National Laboratory; Shinas, Micheal A [Los Alamos National Laboratory

    2010-01-01

    Non-ideal high explosives are typically porous, low-density materials with a low detonation velocity (3--5 km/s) and long detonation reaction zone ({approx} cms). As a result, the interaction of a non-ideal high explosive with an inert confiner can be markedly different than for a conventional high explosive. Issues arise, for example, with light stiff confiners where the confiner can drive the high explosive (HE) through a Prandtl-Meyer fan at the HE/confiner interface rather than the HE driving the confiner. For a non-ideal high explosive confined by a high sound speed inert such that the detonation velocity is lower than the inert sound speed, the flow is subsonic and thus shockless in the confiner. In such cases, the standard detonation shock dynamics methodology, which requires a positive edge-angle be specified at the HE/confiner interface in order that the detonation shape be divergent, cannot be directly utilized. In order to study how detonation shock dynamics can be utilized in such cases, numerical simulations of the detonation of ammonium nitrate-fuel oil (ANFO) confined by aluminum 6061 are conducted.

  1. Case study and lessons learned from the ammonium nitrate explosion at the West Fertilizer facility.

    Science.gov (United States)

    Laboureur, Delphine M; Han, Zhe; Harding, Brian Z; Pineda, Alba; Pittman, William C; Rosas, Camilo; Jiang, Jiaojun; Mannan, M Sam

    2016-05-01

    In West, Texas on April 17, 2013, a chemical storage and distribution facility caught fire followed by the explosion of around 30 tons of ammonium nitrate while the emergency responders were trying to extinguish the fire, leading to 15 fatalities and numerous buildings, businesses and homes destroyed or damaged. This incident resulted in devastating consequences for the community around the facility, and shed light on a need to improve the safety management of local small businesses similar to the West facility. As no official report on the findings of the incident has been released yet, this article first investigates the root causes of the incident, and presents a simplified consequence analysis. The article reviews the regulations applicable to this type of facility and recommended emergency response procedures to identify gaps between what happened in West and the current regulations, and discusses how the current regulations could be modified to prevent or minimize future losses. Finally, the federal response that followed the incident until the publication of this paper is summarized. PMID:26812084

  2. Responses to ammonium and nitrate additions by boreal plants and their natural enemies

    Energy Technology Data Exchange (ETDEWEB)

    Nordin, Annika [Umeaa Plant Science Centre, Department of Forest Genetics and Plant Physiology, Swedish University of Agricultural Sciences, SE-901 83 Umeaa (Sweden)]. E-mail: annika.nordin@genfys.slu.se; Strengbom, Joachim [Department of Ecology and Environmental Sciences, Umeaa University, SE-901 87 Umeaa (Sweden)]. E-mail: joachim.strengbom@ebc.uu.se; Ericson, Lars [Department of Ecology and Environmental Sciences, Umeaa University, SE-901 87 Umeaa (Sweden)]. E-mail: lars.ericson@eg.umu.se

    2006-05-15

    Separate effects of ammonium (NH{sub 4} {sup +}) and nitrate (NO{sub 3} {sup -}) on boreal forest understorey vegetation were investigated in an experiment where 12.5 and 50.0 kg nitrogen (N) ha{sup -1} year{sup -1} was added to 2 m{sup 2} sized plots during 4 years. The dwarf-shrubs dominating the plant community, Vaccinium myrtillus and V. vitis-idaea, took up little of the added N independent of the chemical form, and their growth did not respond to the N treatments. The grass Deschampsia flexuosa increased from the N additions and most so in response to NO{sub 3} {sup -}. Bryophytes took up predominately NH{sub 4} {sup +} and there was a negative correlation between moss N concentration and abundance. Plant pathogenic fungi increased from the N additions, but showed no differences in response to the two N forms. Because the relative contribution of NH{sub 4} {sup +} and NO{sub 3} {sup -} to the total N deposition on a regional scale can vary substantially, the N load a habitat can sustain without substantial changes in the biota should be set considering specific vegetation responses to the predominant N form in deposition. - Biota will respond to nitrogen deposition depending on the form of nitrogen.

  3. Responses to ammonium and nitrate additions by boreal plants and their natural enemies

    International Nuclear Information System (INIS)

    Separate effects of ammonium (NH4+) and nitrate (NO3-) on boreal forest understorey vegetation were investigated in an experiment where 12.5 and 50.0 kg nitrogen (N) ha-1 year-1 was added to 2 m2 sized plots during 4 years. The dwarf-shrubs dominating the plant community, Vaccinium myrtillus and V. vitis-idaea, took up little of the added N independent of the chemical form, and their growth did not respond to the N treatments. The grass Deschampsia flexuosa increased from the N additions and most so in response to NO3-. Bryophytes took up predominately NH4+ and there was a negative correlation between moss N concentration and abundance. Plant pathogenic fungi increased from the N additions, but showed no differences in response to the two N forms. Because the relative contribution of NH4+ and NO3- to the total N deposition on a regional scale can vary substantially, the N load a habitat can sustain without substantial changes in the biota should be set considering specific vegetation responses to the predominant N form in deposition. - Biota will respond to nitrogen deposition depending on the form of nitrogen

  4. Explosions of ammonium nitrate fertilizer in storage or transportation are preventable accidents.

    Science.gov (United States)

    Babrauskas, Vytenis

    2016-03-01

    Ammonium nitrate (AN) is a detonable substance which has led to numerous disasters throughout the 20th century and until the present day, with the latest disaster occurring on 17 April 2013. Needed safety lesson have not been learned, since typically each accident was viewed as a great surprise and investigations focused on finding some unique reason for the accident, rather than examining what is common among the accidents. A review is made of accidents which involved AN for fertilizer purposes, and excluding incidents involving ANFO or additional explosives apart from AN. It is found that, for explosions in storage or transportation, 100% of these disasters had a single causative factor-an uncontrollable fire. Thus, such disasters can be eliminated by eliminating the potential for uncontrolled fire. Two actions are required to achieve this: (1) adoption of fertilizer formulations which reduce the potential for uncontrolled fire and for detonation; and (2) adoption of building safety measures which provide assurance against uncontrolled fires. Technical means are available for achieving both these required measures. These measures have been known for a long time and the only reason that disasters continue to occur is that these safety measures are not implemented. The problem can be solved unilaterally by product manufacturers or by government authorities, but preferably both should take necessary steps. PMID:26547622

  5. Adaptation to osmotic stress provides protection against ammonium nitrate in Pelophylax perezi embryos

    Energy Technology Data Exchange (ETDEWEB)

    Ortiz-Santaliestra, Manuel E., E-mail: ortizsantali@wisc.ed [Department of Animal Biology, University of Salamanca, Campus Miguel de Unamuno, 37007 Salamanca (Spain); Fernandez-Beneitez, Maria Jose, E-mail: may_beneitez@yahoo.e [Department of Animal Biology, University of Salamanca, Campus Miguel de Unamuno, 37007 Salamanca (Spain); Lizana, Miguel, E-mail: lizana@usal.e [Department of Animal Biology, University of Salamanca, Campus Miguel de Unamuno, 37007 Salamanca (Spain); Marco, Adolfo, E-mail: amarco@ebd.csic.e [Donana Biological Station, Spanish Council for Scientific Research, C/Americo Vespucio s/n, 41092 Sevilla (Spain)

    2010-03-15

    The negative effects of pollution on amphibians are especially high when animals are additionally stressed by other environmental factors such as water salinity. However, the stress provoked by salinity may vary among populations because of adaptation processes. We tested the combined effect of a common fertilizer, ammonium nitrate (0-90.3 mg N-NO{sub 3}NH{sub 4}/L), and water salinity (0-2 per mille ) on embryos of two Pelophylax perezi populations from ponds with different salinity concentrations. Embryos exposed to the fertilizer were up to 17% smaller than controls. Survival rates of embryos exposed to a single stressor were always below 10%. The exposure to both stressors concurrently increased mortality rate (>95%) of embryos from freshwater. Since the fertilizer was lethal only when individuals were stressed by the salinity, it did not cause lethal effects on embryos naturally adapted to saline environments. Our results underscore the importance of testing multiple stressors when analyzing amphibian sensitivity to environmental pollution. - Natural resistance to salinity minimizes the impact of chemical fertilizers on amphibian embryos.

  6. Adaptation to osmotic stress provides protection against ammonium nitrate in Pelophylax perezi embryos

    International Nuclear Information System (INIS)

    The negative effects of pollution on amphibians are especially high when animals are additionally stressed by other environmental factors such as water salinity. However, the stress provoked by salinity may vary among populations because of adaptation processes. We tested the combined effect of a common fertilizer, ammonium nitrate (0-90.3 mg N-NO3NH4/L), and water salinity (0-2 per mille ) on embryos of two Pelophylax perezi populations from ponds with different salinity concentrations. Embryos exposed to the fertilizer were up to 17% smaller than controls. Survival rates of embryos exposed to a single stressor were always below 10%. The exposure to both stressors concurrently increased mortality rate (>95%) of embryos from freshwater. Since the fertilizer was lethal only when individuals were stressed by the salinity, it did not cause lethal effects on embryos naturally adapted to saline environments. Our results underscore the importance of testing multiple stressors when analyzing amphibian sensitivity to environmental pollution. - Natural resistance to salinity minimizes the impact of chemical fertilizers on amphibian embryos.

  7. A mathematical model for estimation of distribution in the solvent stripping of uranium from TBP/n-paraffin ammonium nitrate

    International Nuclear Information System (INIS)

    The ammonium nitrate bearing effluent after ADU precipitation can be recycled as strippant in the stripping process of solvent extraction during uranium refining process. The nature of stripping of uranium with various concentration of ammonium nitrate as strippant was studied experimentally and a suitable theoretical model developed for the estimation of Distribution coefficient. The theoretical values of equilibrium constant distribution coefficient was estimated after employing the correction factors due to the activity coefficients each species at higher ionic strength. The activity coefficients of salts in aqueous solution were estimated the correlations developed by 'Bromley' for activity coefficients of multiple salt solutions. The model equations were developed by the mass balance of uranium at equilibrium for biphasic system. Solubility of TBP in water is not considered in the equation so developed. Also the model does not take into account for the ideality of organic phase

  8. Automated, colorimetric methods for determination of nitrate plus nitrite, nitrite, ammonium and orthophosphate ions in natural water samples

    Science.gov (United States)

    Antweiler, Ronald C.; Patton, Charles J.; Taylor, Howard E.

    1996-01-01

    The apparatus and methods used for the automatic, colorimetric determinations of dissolved nutrients (nitrate plus nitrite, nitrite, ammonium and orthophosphate) in natural waters are described. These techniques allow for the determination of nitrate plus nitrite for the concentration range 0.02 to 8 mg/L (milligrams per liter) as N (nitrogen); for nitrite, the range is 0.002 to 1.0 mg/L as N; for ammonium, the range is 0.006 to 2.0 mg/L as N; and for orthophosphate, the range is 0.002 to 1.0 mg/L as P (phosphorus). Data are presented that demonstrate the accuracy, precision and quality control of the methods.

  9. Effect of biochar amendment on sorption and leaching of nitrate, ammonium, and phosphate in a sandy soil.

    Science.gov (United States)

    Yao, Ying; Gao, Bin; Zhang, Ming; Inyang, Mandu; Zimmerman, Andrew R

    2012-11-01

    When applied to soils, it is unclear whether and how biochar can affect soil nutrients. This has implications both to the availability of nutrients to plants or microbes, as well as to the question of whether biochar soil amendment may enhance or reduce the leaching of nutrients. In this work, a range of laboratory experiments were conducted to determine the effect of biochar amendment on sorption and leaching of nitrate, ammonium, and phosphate in a sandy soil. A total of thirteen biochars were tested in laboratory sorption experiments and most of them showed little/no ability to sorb nitrate or phosphate. However, nine biochars could remove ammonium from aqueous solution. Biochars made from Brazilian pepperwood and peanut hull at 600°C (PH600 and BP600, respectively) were used in a column leaching experiment to assess their ability to hold nutrients in a sandy soil. The BP600 biochar effectively reduced the total amount of nitrate, ammonium, and phosphate in the leachates by 34.0%, 34.7%, and 20.6%, respectively, relative to the soil alone. The PH600 biochar also reduced the leaching of nitrate and ammonium by 34% and 14%, respectively, but caused additional phosphate release from the soil columns. These results indicate that the effect of biochar on the leaching of agricultural nutrients in soils is not uniform and varies by biochar and nutrient type. Therefore, the nutrient sorption characteristics of a biochar should be studied prior to its use in a particular soil amendment project. PMID:22763330

  10. Effect of ammonium and nitrate source of nitrogen on productivity of photosynthesis in Scots pine (Pinus silvestris L.) seedlings

    OpenAIRE

    A. Łotocki; W. Żelawski

    2015-01-01

    Water culture and sand culture seedlings of Scots pine were investigated in respect to their reaction to ammonium or nitrate source of nitrogen nutrition. Photosynthesis, respiration, and dry matter production were studied in three and four months old plants. The results are preliminary but they have indicated that the effect of various form of nitrogen nutrition on gas exchange and growth rates could change during the growing season.

  11. Burning Characteristics of Ammonium-Nitrate-Based Composite Propellants with a Hydroxyl-Terminated Polybutadiene/Polytetrahydrofuran Blend Binder

    OpenAIRE

    Makoto Kohga; Tomoki Naya; Kayoko Okamoto

    2012-01-01

    Ammonium-nitrate-(AN-) based composite propellants prepared with a hydroxyl-terminated polybutadiene (HTPB)/polytetrahydrofuran (PTHF) blend binder have unique thermal decomposition characteristics. In this study, the burning characteristics of AN/HTPB/PTHF propellants are investigated. The specific impulse and adiabatic flame temperature of an AN-based propellant theoretically increases with an increase in the proportion of PTHF in the HTPB/PTHF blend. With an AN/HTPB propellant, a solid res...

  12. Exogenous nitrate attenuates nitrite toxicity to anaerobic ammonium oxidizing (anammox) bacteria.

    Science.gov (United States)

    Li, Guangbin; Vilcherrez, David; Carvajal-Arroyo, Jose Maria; Sierra-Alvarez, Reyes; Field, Jim A

    2016-02-01

    Anaerobic ammonium oxidizing bacteria (anammox) can be severely inhibited by one of its main substrates, nitrite (NO2(-)). At present, there is limited information on the processes by which anammox bacteria are able to tolerate toxic NO2(-). Intracellular consumption or electrochemically driven (transmembrane proton motive force) NO2(-) export are considered the main mechanisms of NO2(-) detoxification. In this work, we evaluated the potential of exogenous nitrate (NO3(-)) on relieving NO2(-) toxicity, putatively facilitated by NarK, a NO3(-)/NO2(-) transporter encoded in the anammox genome. The relative contribution of NO3(-) to NO2(-) detoxification was found to be pH dependent. Exposure of anammox cells to NO2(-) in absence of their electron donating substrate, ammonium (NH4(+)), causes NO2(-) stress. At pH 6.7 and 7.0, the activity of NO2(-) stressed cells was respectively 0 and 27% of the non-stressed control activity (NO2(-) and NH4(+) fed simultaneously). Exogenous NO3(-) addition caused the recovery to 42% and 80% of the control activity at pH 6.7 and 7.0, respectively. The recovery of the activity of NO2(-) stressed cells improved with increasing NO3(-) concentration, the maximum recovery being achieved at 0.85 mM. The NO3(-) pre-incubation time is less significant at pH 7.0 than at pH 6.7 due to a more severe NO2(-) toxicity at lower pH. Additionally, NO3(-) caused almost complete attenuation of NO2(-) toxicity in cells exposed to the proton gradient disruptor carbonyl cyanide m-chlorophenyl hydrazone at pH 7.5, providing evidence that the NO3(-) attenuation is independent of the proton motive force. The absence of a measurable NO3(-) consumption (or NO3(-) dependent N2 production) during the batch tests leaves NO3(-) dependent active transport of NO2(-) as the only plausible explanation for the relief of NO2(-) inhibition. We suggest that anammox cells can use a secondary transport system facilitated by exogenous NO3(-) to alleviate NO2(-) toxicity. PMID

  13. Liquid phase nitration of benzene over supported ammonium salt of 12-molybdophosphoric acid catalysts prepared by sol-gel method

    International Nuclear Information System (INIS)

    A mild and clean liquid nitration of benzene with 65% nitric acid as nitrating agent over silica supported ammonium salt of 12-molybdophosphoric acid catalysts has been investigated. These catalysts with different loadings were prepared by sol-gel method and characterized by X-ray diffraction (XRD) and FTIR spectra. The acidity of these catalysts was measured by the potentiometric titration method. The XRD and IR analysis revealed that supported catalysts possess the Keggin structure which is similar to 12-molybdophosphoric acid. And it can be found that the supported catalysts had high nitration reaction catalytic activity and selectivity over nitrobenzene. The effects of various parameters such as nitric acid/benzene volume ratio, temperature and time of reaction have also been systematically studied.

  14. Exchange of reactive nitrogen compounds: concentrations and fluxes of total ammonium and total nitrate above a spruce forest canopy

    Directory of Open Access Journals (Sweden)

    V. Wolff

    2009-11-01

    Full Text Available Total ammonium (tot-NH4+ and total nitrate (tot-NO3 provide a chemically conservative quantity in the measurement of exchange processes of reactive nitrogen compounds ammonia (NH3, particulate ammonium (NH4+, nitric acid (HNO3, and particulate nitrate (NO3, using the aerodynamic gradient method. Total fluxes were derived from concentration differences of total ammonium (NH3 and NH4+ and total nitrate (HNO3 and NO3 measured at two levels. Gaseous species and related particulate compounds were measured selectively, simultaneously and continuously above a spruce forest canopy in south-eastern Germany in summer 2007. Measurements were performed using a wet-chemical two-point gradient instrument, the GRAEGOR. Median concentrations of NH3, HNO3, NH4, and NO3 were 0.57, 0.12, 0.76, and 0.48 μg m−3, respectively. Total ammonium and total nitrate fluxes showed large variations depending on meteorological conditions, with concentrations close to zero under humid and cool conditions and higher concentrations under dry conditions. Mean fluxes of total ammonium and total nitrate in September 2007 were directed towards the forest canopy and were −65.77 ng m−2 s−1 and −41.02 ng m−2 s−1 (in terms of nitrogen, respectively. Their deposition was controlled by aerodynamic resistances only, with very little influence of surface resistances. Including measurements of wet deposition and findings of former studies at the study site on occult deposition (fog water interception, the total N deposition in September 2007 was estimated to 5.86 kg ha−1.

  15. Exchange of reactive nitrogen compounds: concentrations and fluxes of total ammonium and total nitrate above a spruce canopy

    Directory of Open Access Journals (Sweden)

    V. Wolff

    2010-05-01

    Full Text Available Total ammonium (tot-NH4+ and total nitrate (tot-NO3 provide chemically conservative quantities in the measurement of surface exchange of reactive nitrogen compounds ammonia (NH3, particulate ammonium (NH4+, nitric acid (HNO3, and particulate nitrate (NO3, using the aerodynamic gradient method. Total fluxes were derived from concentration differences of total ammonium (NH3 and NH4+ and total nitrate (HNO3 and NO3 measured at two levels. Gaseous species and related particulate compounds were measured selectively, simultaneously and continuously above a spruce forest canopy in south-eastern Germany in summer 2007. Measurements were performed using a wet-chemical two-point gradient instrument, the GRAEGOR. Median concentrations of NH3, HNO3, NH4+, and NO3 were 0.57, 0.12, 0.76, and 0.48 μg m−3, respectively. Total ammonium and total nitrate fluxes showed large variations depending on meteorological conditions, with concentrations close to zero under humid and cool conditions and higher concentrations under dry conditions. Mean fluxes of total ammonium and total nitrate in September 2007 were directed towards the forest canopy and were −65.77 ng m−2 s−1 and −41.02 ng m−2 s−1 (in terms of nitrogen, respectively. Their deposition was controlled by aerodynamic resistances only, with very little influence of surface resistances. Including measurements of wet deposition and findings of former studies on occult deposition (fog water interception at the study site, the total N deposition in September 2007 was estimated to 5.86 kg ha−1.

  16. Ammonium nitrate evaporation and nitric acid condensation in DMT CCN counters

    Science.gov (United States)

    Romakkaniemi, S.; Jaatinen, A.; Laaksonen, A.; Nenes, A.; Raatikainen, T.

    2014-05-01

    The effect of inorganic semivolatile aerosol compounds on the cloud condensation nucleus (CCN) activity of aerosol particles was studied by using a computational model for a DMT-CCN counter, a cloud parcel model for condensation kinetics and experiments to quantify the modelled results. Concentrations of water vapour and semivolatiles as well as aerosol trajectories in the CCN column were calculated by a computational fluid dynamics model. These trajectories and vapour concentrations were then used as an input for the cloud parcel model to simulate mass transfer kinetics of water and semivolatiles between aerosol particles and the gas phase. Two different questions were studied: (1) how big a fraction of semivolatiles is evaporated from particles after entering but before particle activation in the DMT-CCN counter? (2) How much can the CCN activity be increased due to condensation of semivolatiles prior to the maximum water supersaturation in the case of high semivolatile concentration in the gas phase? Both experimental and modelling results show that the evaporation of ammonia and nitric acid from ammonium nitrate particles causes a 10 to 15 nm decrease to the critical particle size in supersaturations between 0.1% and 0.7%. On the other hand, the modelling results also show that condensation of nitric acid or similar vapour can increase the CCN activity of nonvolatile aerosol particles, but a very high gas phase concentration (as compared to typical ambient conditions) would be needed. Overall, it is more likely that the CCN activity of semivolatile aerosol is underestimated than overestimated in the measurements conducted in ambient conditions.

  17. 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.

  18. Ceric ammonium nitrate catalysed three component one-pot efficient synthesis of 2,4,5-triaryl-1H-imidazoles

    Indian Academy of Sciences (India)

    Jaiprakash N Sangshetti; Nagnnath D Kokare; Sandeep A Kotharkara; Devanand B Shinde

    2008-09-01

    Ceric ammonium nitrate (CAN) is used as an efficient catalyst for the synthesis of 2,4,5-triaryl-1H-imidazoles via condensation of benzoin/benzil, ammonium acetate, and aromatic aldehydes. The easy work-up, higher yields and shorter reaction time are the advantages of the method presented here.

  19. Polyethylene Glycols as Efficient Media for Decarboxylative Nitration of α,β-Unsaturated Aromatic Carboxylic Acids by Ceric Ammonium Nitrate in Acetonitrile Medium: A Kinetic and Mechanistic Study

    Directory of Open Access Journals (Sweden)

    K. Ramesh

    2013-01-01

    Full Text Available Polyethylene glycols (PEGs were found to be efficient media for decarboxylative nitration of α,β-unsaturated aromatic carboxylic acids by ceric ammonium nitrate (CAN in acetonitrile to give β-nitrostyrene derivatives. Kinetics of the reaction exhibited second order kinetics with a first order dependence on [CAN] and [substrate]. Reactions were too sluggish to be studied in the absence of PEG; therefore detailed kinetics were not taken up. Reaction times were reduced from 24 hrs to few hours. The catalytic activity was found to be in the increasing order PEG-300 > PEG-400 > PEG-600 > PEG-200. Mechanism of PEG-mediated reactions was explained by Menger-Portnoy's scheme as applied in micellar kinetics.

  20. Effect of Energetic Materials on Thermal Decomposition of Phase-Stabilised Ammonium Nitrate - An Eco-Friendly Oxidiser

    Directory of Open Access Journals (Sweden)

    Suresh Mathew

    1999-01-01

    Full Text Available Phase-stabilised ammonium nitrate (PSAN was prepared by incorporating copper (II diamine nitrate in the ammonium nitrate (AN crystal lattice, thereby avoiding the abrupt volume change within the useful temperature range. The effect of RDX on the thermal decomposition of PSAN has been investigated. Decomposition temperatures of PSAN and RDX are almost in the same temperature range. The synergetic effect of the interaction between PSAN and RDX resulted in a net exothermic reaction of PSAN. The kinetic and thermodynamic parameters of the exothermic decomposition have been computed. Two well-known equations based on variable programme heating rate method, viz., Kissinger and Ozawa equations were employed for the kinetic evaluation. The approximate activation energy obtained from Ozawa method was refined by an iteration procedure using the two-term approximation for Arrhenius temperature integral, p(x and the refinement was found to be unwarranted for the reaction. There is a close agreement between the values of kinetic parameters of the exothermic reaction of PSAN and RDX obtained from the Kissinger and Ozawa methods. "

  1. interface mechanical properties of gun propellant coated with ammonium nitrate%包覆硝酸铵发射药界面力学性能研究

    Institute of Scientific and Technical Information of China (English)

    武子元; 贺增弟

    2012-01-01

    Interface mechanical properties of gun propellant coated with ammonium nitrate were studied. The effects of contents and particle sizes of ammonium nitrate and temperature on the interface shear strength of gun propellant were studied by stretching shear and compress experimental method. The results showed that as the content of ammonium nitrate increased, interface shear strength of gun propellant was gradually decreased. As the particle sizes of ammonium nitrate decreased, interface shear strength of gun propellant was gradually increased. And as the temperature rose, interface shear strength of gun propellant were gradually increased then decreased. When ammonium nitrate translated into 13-rhombohedra, compressive strength of gun propellant was increased; when ammonium nitrate translated into tetragonal system, compressive strength of gun propellant was decreased. The study results were valuable for the applica- tion of gun propellant coated with ammonium nitrate.%研究包覆硝酸铵发射药的界面力学性能。采用拉伸剪切和压缩的方法测定在不同硝酸铵含量、不同硝酸铵粒径、不同温度下包覆硝酸铵发射药的界面剪切强度。实验结果表明,随着硝酸铵含量的升高,发射药的界面剪切强度先上升再下降;随着硝酸铵粒径的降低,发射药的界面剪切强度不断下降;随着温度的升高,发射药的界面剪切强度先升高再降低。

  2. Natural and transboundary pollution influences on sulfate-nitrate-ammonium aerosols in the United States: Implications for policy

    Science.gov (United States)

    Park, Rokjin J.; Jacob, Daniel J.; Field, Brendan D.; Yantosca, Robert M.; Chin, Mian

    2004-08-01

    We use a global three-dimensional coupled oxidant-aerosol model (GEOS-CHEM) to estimate natural and transboundary pollution influences on sulfate-nitrate-ammonium aerosol concentrations in the United States. This work is motivated in part by the Regional Haze Rule of the U.S. Environmental Protection Agency (EPA), which requires immediate action to improve visibility in U.S. wilderness areas along a linear trajectory toward an endpoint of "natural visibility conditions" by 2064. We present full-year simulations for 1998 and 2001 and evaluate them with nationwide networks of observations in the United States and Europe (Interagency Monitoring of Protected Visual Environments (IMPROVE), Clean Air Status and Trends Network (CASTNET), National Atmospheric Deposition Program (NADP), European Monitoring and Evaluation Programme (EMEP)) and with Asian outflow observations from the NASA Transport and Chemical Evolution over the Pacific (TRACE-P) aircraft mission. Shutting off U.S. anthropogenic emissions in the model defines "background" aerosol concentrations representing contributions from both natural and transboundary pollution sources. We find that transboundary transport of pollution from Canada, Mexico, and Asia dominates over natural influences for both sulfate and nitrate. Trans-Pacific transport of Asian pollution accounts for 30% of background sulfate in both the western and eastern United States. Our best estimates of natural concentrations for ammonium sulfate and ammonium nitrate in the United States are either consistent with or lower than the default values recommended by EPA for natural visibility calculations. However, the large transboundary pollution influence in our calculation suggests that a natural visibility objective cannot be approached without international emission controls.

  3. Simulations of Sulfate-Nitrate-Ammonium (SNA) aerosols during the extreme haze events over Northern China in 2014

    Energy Technology Data Exchange (ETDEWEB)

    Chen, Dan; Liu, Zhiquan; Fast, Jerome D.; Ban, Junmei

    2016-08-30

    Extreme haze events have occurred frequently over China in recent years. Although many studies have investigated the formation mechanisms associated with PM2.5 for heavily polluted regions in China based on observational data, adequately predicting peak PM2.5 concentrations is still challenging for regional air quality models. In this study, we evaluate the performance of one configuration of the Weather Research and Forecasting model coupled with chemistry (WRF-Chem) and use the model to investigate the sensitivity of heterogeneous reactions on simulated peak sulfate, nitrate, and ammonium concentrations in the vicinity of Beijing during four extreme haze episodes in October 2014 over the North China Plain. The highest observed PM2.5 concentration of 469 μg m-3 occurred in Beijing. Comparisons with observations show that the model reproduced the temporal variability in PM2.5 with the highest PM2.5 values on polluted days (defined as days in which observed PM2.5 is greater than 75 μg m-3), but predictions of sulfate, nitrate, and ammonium were too low on days with the highest observed concentrations. Observational data indicate that the sulfur/nitric oxidation rates are strongly correlated with relative humidity during periods of peak PM2.5; however, the model failed to reproduce the highest PM2.5 concentrations due to missing heterogeneous reactions. As the parameterizations of those reactions is not well established yet, estimates of SO2-to-H2SO4 and NO2/NO3-to-HNO3 reaction rates that depend on relative humidity were applied which improved the simulation of sulfate, nitrate, and ammonium enhancement on polluted days in terms of both concentrations and partitioning among those species. Sensitivity simulations showed that the extremely high heterogeneous reaction rates and also higher emission rates than those reported in the emission inventory

  4. Natural and transboundary pollution influences on sulfate-nitrate-ammonium aerosols in the United States: Implications for policy

    OpenAIRE

    Park, Rokjin J.; Jacob, Daniel James; Field, Brendan; Yantosca, Robert M.; Chin, Mian

    2004-01-01

    We use a global three-dimensional coupled oxidant-aerosol model (GEOS-CHEM) to estimate natural and transboundary pollution influences on sulfate-nitrate-ammonium aerosol concentrations in the United States. This work is motivated in part by the Regional Haze Rule of the U.S. Environmental Protection Agency (EPA), which requires immediate action to improve visibility in U.S. wilderness areas along a linear trajectory toward an endpoint of “natural visibility conditions” by 2064. We present fu...

  5. Increased rates of dissimilatory nitrate reduction to ammonium (DNRA) under oxic conditions in a periodically hypoxic estuary

    Science.gov (United States)

    Roberts, Keryn L.; Kessler, Adam J.; Grace, Michael R.; Cook, Perran L. M.

    2014-05-01

    The Yarra River Estuary is a salt wedge estuary prone to hypoxia in the bottom waters during low flow periods. Rates of denitrification and dissimilatory nitrate reduction to ammonium (DNRA) were quantified using 15N in relation to oxygen, nitrate and available reductants. Denitrification was the dominant nitrate reduction pathway under all oxygen conditions, however, DNRA increased from denitrifying bacteria had a higher affinity than nitrate ammonifying bacteria with Km values of 49 and 86 μmol L-1 for denitrification and DNRA, respectively, however, this could not explain the change in the rates of DNRA relative to denitrification observed. Further slurry incubations to investigate the relationship between DNRA and Fe2+ oxidation were inconclusive and complicated by very high backgrounds of sorbed (HCl extractable) Fe2+. Addition of Fe2+ to the slurry did not stimulate denitrification compared to a control (no Fe2+ addition), however, there was a significant decrease in the Fe2+ concentration over the period where DNRA occurred in the Fe2+ addition treatment, and no significant decrease in the control treatment. The ratio of DNRA to Fe2+ consumption was 15 ± 6 and 7 ± 3 for the Fe2+ and control treatments, respectively. We suggest reduced rates of DNRA under anoxic conditions can be explained by the binding of Fe2+ with free sulfides and the formation of FeS removing available Fe2+ for DNRA.

  6. Airborne Measurements of Ammonia and Implications for Ammonium Nitrate Formation in the Central Valley and the South Coast Air Basin of California

    Science.gov (United States)

    Nowak, J. B.; Neuman, J.; Bahreini, R.; Middlebrook, A. M.; Brock, C. A.; Frost, G. J.; Holloway, J. S.; McKeen, S. A.; Peischl, J.; Pollack, I. B.; Roberts, J. M.; Ryerson, T. B.; Trainer, M.; Parrish, D. D.

    2010-12-01

    Ammonia (NH3) is the dominant gas-phase base in the troposphere. As a consequence, NH3 abundance influences aerosol formation and composition. Ammonium nitrate aerosol is formed from the reaction of gas phase NH3 and nitric acid (HNO3). Anthropogenic emissions of NH3 and NOx (NO + NO2), which in sunlight can be oxidized to form HNO3, can react to form ammonium nitrate aerosol. Agricultural activity (i.e., dairy farms), and urban centers (i.e., Fresno, Los Angeles) are sources of ammonium nitrate gas-phase precursors in both the Central Valley and the South Coast Air Basin. Airborne measurements of NH3, HNO3, particle composition, and particle size distribution were made aboard the NOAA WP-3D research aircraft during May and June 2010 in the Central Valley and the South Coast Air Basin of California, as part of CalNex 2010 (California Research at the Nexus of Air Quality and Climate Change). The highest mixing ratios of NH3, well over 100 parts-per-billion by volume (ppbv), were measured downwind of dairy farms. The high NH3 mixing ratios were highly anti-correlated with HNO3 mixing ratios on fast time scales (~1 s) that correspond to short flight distances (~100 m). During these periods particulate nitrate (NO3-) concentrations increased, indicating ammonium nitrate formation. The meteorological and chemical environments during these periods will be studied to determine the factors driving or limiting ammonium nitrate formation and the resulting regional differences. Finally, the relationship between the NH3 observations and NH3 sources will be examined to assess the emissions and their contribution to ammonium nitrate abundance.

  7. Responses of toad tadpoles to ammonium nitrate fertilizer and predatory stress: differences between populations on a local scale.

    Science.gov (United States)

    Ortiz-Santaliestra, Manuel E; Fernández-Benéitez, María José; Lizana, Miguel; Marco, Adolfo

    2011-06-01

    Agriculture-related pollution is among the major causes of global amphibian population declines. The multiple stressors to which amphibians are exposed in the field, such as predation pressure, can make agrochemicals far more deadly than when they act in isolation. Even within a small area, diffuse agricultural pollution does not affect all aquatic environments equally, which could account for local differences in amphibian sensitivity to agrochemicals. We examined the combined effects of ammonium nitrate fertilizer (0 to 45.2 mg N-NH 4(+)/L) and predator stress on larval Western spadefoot toad (Pelobates cultripes), using adult caged male marbled newts (Triturus marmoratus) as predators. We compared the interaction between both stressors in tadpoles from two ponds separated by 3 km. No significant mortality was observed (survival > 80% in all cases). Local differences were detected when analyzing larval growth, with a significant interaction between factors for one of the two populations tested (Fornillos de Fermoselle). Although tadpoles exposed to 45.2 mg N-NH 4(+)/L were 7% smaller than controls, the presence of predators from a foreign community resulted in animals 15% larger than those raised without predators after 15 d of experiment. Interestingly, predators from the same community as the tadpoles did not affect larval growth. The length of the tadpoles from a nearby location (Mámoles) was unaffected after exposure to ammonium nitrate and predatory stress. PMID:21384420

  8. Nitrogen-limited mangrove ecosystems conserve N through dissimilatory nitrate reduction to ammonium

    OpenAIRE

    Fernandes, Sheryl Oliveira; Bonin, Patricia C.; Michotey, Valérie D.; Garcia, Nicole; P.A. Lokabharathi

    2012-01-01

    Earlier observations in mangrove sediments of Goa, India have shown denitrification to be a major pathway for N loss1. However, percentage of total nitrate transformed through complete denitrification accounted for

  9. Reducing nitrous oxide emissions by changing N fertiliser use from calcium ammonium nitrate (CAN) to urea based formulations.

    Science.gov (United States)

    Harty, M A; Forrestal, P J; Watson, C J; McGeough, K L; Carolan, R; Elliot, C; Krol, D; Laughlin, R J; Richards, K G; Lanigan, G J

    2016-09-01

    The accelerating use of synthetic nitrogen (N) fertilisers, to meet the world's growing food demand, is the primary driver for increased atmospheric concentrations of nitrous oxide (N2O). The IPCC default emission factor (EF) for N2O from soils is 1% of the N applied, irrespective of its form. However, N2O emissions tend to be higher from nitrate-containing fertilisers e.g. calcium ammonium nitrate (CAN) compared to urea, particularly in regions, which have mild, wet climates and high organic matter soils. Urea can be an inefficient N source due to NH3 volatilisation, but nitrogen stabilisers (urease and nitrification inhibitors) can improve its efficacy. This study evaluated the impact of switching fertiliser formulation from calcium ammonium nitrate (CAN) to urea-based products, as a potential mitigation strategy to reduce N2O emissions at six temperate grassland sites on the island of Ireland. The surface applied formulations included CAN, urea and urea with the urease inhibitor N-(n-butyl) thiophosphoric triamide (NBPT) and/or the nitrification inhibitor dicyandiamide (DCD). Results showed that N2O emissions were significantly affected by fertiliser formulation, soil type and climatic conditions. The direct N2O emission factor (EF) from CAN averaged 1.49% overall sites, but was highly variable, ranging from 0.58% to 3.81. Amending urea with NBPT, to reduce ammonia volatilisation, resulted in an average EF of 0.40% (ranging from 0.21 to 0.69%)-compared to an average EF of 0.25% for urea (ranging from 0.1 to 0.49%), with both fertilisers significantly lower and less variable than CAN. Cumulative N2O emissions from urea amended with both NBPT and DCD were not significantly different from background levels. Switching from CAN to stabilised urea formulations was found to be an effective strategy to reduce N2O emissions, particularly in wet, temperate grassland. PMID:27155080

  10. The effect of soot on ammonium nitrate species and NO2 selective catalytic reduction over Cu-zeolite catalyst-coated particulate filter.

    Science.gov (United States)

    Mihai, Oana; Tamm, Stefanie; Stenfeldt, Marie; Olsson, Louise

    2016-02-28

    A selective catalytic reduction (SCR)-coated particulate filter was evaluated by means of dynamic tests performed using NH3, NO2, O2 and H2O. The reactions were examined both prior to and after soot removal in order to study the effect of soot on ammonium nitrate formation and decomposition, ammonia storage and NO2 SCR. A slightly larger ammonia storage capacity was observed when soot was present in the sample, which indicated that small amounts of ammonia can adsorb on the soot. Feeding of NO2 and NH3 in the presence of O2 and H2O at low temperature (150, 175 and 200°C) leads to a large formation of ammonium nitrate species and during the subsequent temperature ramp using H2O and argon, a production of nitrous oxides was observed. The N2O formation is often related to ammonium nitrate decomposition, and our results showed that the N2O formation was clearly decreased by the presence of soot. We therefore propose that in the presence of soot, there are fewer ammonium nitrate species on the surface due to the interactions with the soot. Indeed, we do observe CO2 production during the reaction conditions also at 150°C, which shows that there is a reaction with these species and soot. In addition, the conversion of NOx due to NO2 SCR was significantly enhanced in the presence of soot; we attribute this to the smaller amount of ammonium nitrate species present in the experiments where soot is available since it is well known that ammonium nitrate formation is a major problem at low temperature due to the blocking of the catalytic sites. Further, a scanning electron microscopy analysis of the soot particles shows that they are about 30-40 nm and are therefore too large to enter the pores of the zeolites. There are likely CuxOy or other copper species available on the outside of the zeolite crystallites, which could have been enhanced due to the hydrothermal treatment at 850°C of the SCR-coated filter prior to the soot loading. We therefore propose that soot is

  11. Increase in the biomass of some green algae species in nitrate and ammonium mediums depending on auto-, mixo- or heterotrophic conditions

    Directory of Open Access Journals (Sweden)

    Stefan Gumiński

    2014-02-01

    Full Text Available The increase in total dry mass and protein in cultures of Chlorella pyrenoidosa, Scenedesmus quadricauda and Ankistrodesmus acicularis was studied. Under autotrophic conditions, increases in dry mass were, as a rule, larger in the nitrate medium than in the ammonium one, under mixotrophic conditions the situation was reversed and in the case of heterotrophy, the individual species reacted differently. The dependence ot the protein content increase on the nitrate or ammonium form of the medium was not clear. Changes in time of the pH and rH of the mediums were followed and the interdependence of these changes with the production of biomass is discussed.

  12. Protonic Ammonium Nitrate Ionic Liquids and Their Mixtures: Insights into Their Thermophysical Behavior.

    Science.gov (United States)

    Canongia Lopes, José N; Esperança, José M S S; de Ferro, André Mão; Pereiro, Ana B; Plechkova, Natalia V; Rebelo, Luis P N; Seddon, Kenneth R; Vázquez-Fernández, Isabel

    2016-03-10

    This study is centered on the thermophysical characterization of different families of alkylammonium nitrate ionic liquids and their binary mixtures, namely the determination at atmospheric pressure of densities, electric conductivities and viscosities in the 288.15 liquids with differing numbers of hydrogen bond donor groups: diethylammonium nitrate (two hydrogen bond donors), triethylammonium nitrate (one hydrogen bond donor) and tetraethylammonium nitrate (no hydrogen bond donors). Finally, the behavior of mixtures with different numbers of equivalent carbon atoms in the alkylammonium cations was analyzed. The results show a quasi-ideal behavior for all monoalkylammonium nitrate mixtures. In contrast, the other mixtures show deviations from ideality, namely when the difference in the number of carbon atoms present in the cations increases or the number of hydrogen bond donors present in the cation decreases. Overall, the results clearly show that, besides the length and distribution of alkyl chains present in a cation such as alkylammonium, there are other structural and interaction parameters that influence the thermophysical properties of both pure compounds and their mixtures. PMID:26886188

  13. [Simultaneous Biotransformation of Ammonium and Nitrate via Zero-Valent Iron on Anaerobic Conditions].

    Science.gov (United States)

    Zhou, Jian; Huang, Yong; Yuan, Yi; Liu, Xin; Li, Xiang; Shen, Jie; Yang, Peng-bing

    2015-12-01

    Zero-valent iron (ZVI) was used to improve the biological autotrophic denitrification process between nitrate and ammonia by anaerobic ammonia oxidation ( ANAMMOX) bacteria. With the addition of ZVI, the biological autotrophic denitrification process could be reacted in the influent condition of pH was 7-8, at 35°C ±0.5°C, the concentration of ammonia was 50-100 mg · L⁻¹ and the concentration of nitrate was 50-100 mg · L⁻¹. The highest conversion rate could be reached to 17.2 mg · (L·h) ⁻¹. With the change of reaction time and the molar ratio of nitrate and ammonia in influent, the final molar conversion ratio of nitrate and ammonia in effluent fluctuated between 1.2-3. 5. The result showed that this autotrophic denitrification process was not belonged to elementary reaction. The mechanism of this autotrophic denitrification process could be summarized that with the reduction of ZVI, the nitrate could be reduced to nitrite. Hereafter, the ANAMMOX process reacted between the nitrite and ammonia. PMID:27011992

  14. Electrochemical obtaining of ammonium polyuranate (yellow residuum) from nitrate-sulfuric acid commodity eluates

    International Nuclear Information System (INIS)

    Reagent free electrochemical separation of ammonium polyuranate from acid commercial desorbates obtained on the areas of underground leaching of uranium during sorption reprocessing of producing solutions was investigated. Simulator solution containing, g/l: U - 10.9, Fe+3 - 0.48, Al - 0.21, NH4NO3 - 60, (NH4)SO4 - 10 was suffered by the electrochemical treatment. Optimum process parameters were determined. It is established that the use of the development method makes possible raise the grade of the separated yellow residuum and drop operating consumptions for the preparation of 1 kg of uranium by 20 % in finished product as compared with chemical precipitation of the ammonium polyuranate

  15. The importance of dissimilatory nitrate reduction to ammonium (DNRA) in the nitrogen cycle of coastal ecosystems

    DEFF Research Database (Denmark)

    Giblin, Anne E.; Tobias, Craig R.; Song, Bongkeun;

    2013-01-01

    Until recently, it was believed that biological assimilation and gaseous nitrogen (N) loss through denitrification were the two major fates of nitrate entering or produced within most coastal ecosystems. Denitrification is often viewed as an important ecosystem service that removes reactive N fro...

  16. Nitrogen-limited mangrove ecosystems conserve N through dissimilatory nitrate reduction to ammonium.

    Science.gov (United States)

    Fernandes, Sheryl Oliveira; Bonin, Patricia C; Michotey, Valérie D; Garcia, Nicole; LokaBharathi, P A

    2012-01-01

    Earlier observations in mangrove sediments of Goa, India have shown denitrification to be a major pathway for N loss. However, percentage of total nitrate transformed through complete denitrification accounted for climate by modulating the production of the greenhouse gas nitrous oxide. PMID:22639727

  17. 77 FR 65532 - Solid Fertilizer Grade Ammonium Nitrate From the Russian Federation: Notice of Rescission of...

    Science.gov (United States)

    2012-10-29

    ... Nitrate from Russia: Correction to Notice of Opportunity to Request Administrative Review, 77 FR 21527... Requests for Revocation in Part, 77 FR 31586, 31570 (May 29, 2012). \\3\\ See the June 5, 2012, memorandum... Rescission of Antidumping Duty Administrative Review, 77 FR 32498 (June 1, 2012); and Certain Steel...

  18. Sequential diffusion of ammonium and nitrate from soil extracts to a polytetrafluoroethylene trap for 15N determination

    International Nuclear Information System (INIS)

    A novel diffusion method was used for preparation of NH4+- and NO3--N samples from soil extracts for 15N determination. Ammonium, and nitrate following reduction to ammonia, are allowed to diffuse to an acid-wetted glass filter enclosed in polytetrafluoroethylene tape. The method was evaluated with simulated soil extracts obtained using 50 ml of 2 M potassium chloride solution containing 130 μg of NH4=-N (2.3 atom% 15N) and 120 μg of NO3--N (natural 15N abundance). No cross-over in the 15N abundances of NH4+-N and NO3--N was observed, indicating a quantitative diffusion process (72 h, 25 deg C). Owing to the presence of inorganic nitrogen impurities in the potassium chloride, the 15N enrichments should be corrected for the blank nitrogen content. (author). 8 refs.; 1 tab

  19. Effect of method of crystallization on the IV-III and IV-II polymorphic transitions of ammonium nitrate

    International Nuclear Information System (INIS)

    A study has been undertaken on the effect of crystallization method on the IV ↔ III transition of ammonium nitrate (AN). AN is crystallized in three different ways, viz. recrystallization, evaporative crystallization and melt crystallization. When the samples were crystallized from saturated aqueous solution, ideal crystals were formed, which behaved differently from the crystals formed from the other methods. The DTA examination of the crystals showed that the crystals have different transition behaviour. The moisture uptake of the samples determined were found to have influenced by the mode of crystallization. The samples were further analyzed by powder X-ray diffraction (XRD) and scanning electron microscopy (SEM). The present study showed that the parameters like thermal history, number of previous transformations and moisture content have a very negligible influence on the IV ↔ III transition of AN as compared to the method of crystallization

  20. Toxicity of Ambient Particulate Matter. III. Acute toxicity study in asthmatic mice following 3-day exposure to ultrafine and fine ammonium nitrate, a model compound for secondary aerosol fraction of PM10

    NARCIS (Netherlands)

    Cassee FR; Dormans JAMA; Loveren H van; Bree L van; Rombout PJA; LEO; LPI

    1998-01-01

    Ammonium nitrate is the most prominent component of secondary PM10 in the Netherlands. In our study, healthy and asthmatic mice were exposed to fine (CMD = 0.3 mum; 4 x 10 exp. 3 particles per cm3) and ultrafine (CMD = 0.03 mum; 2 x 10. exp. 5 particles per cm3) ammonium nitrate. The mean mass conc

  1. Uranium value leaching with ammonium carbonate and/or bicarbonate plus nitrate oxidant and optionally oxidation-catalytic metal compounds

    International Nuclear Information System (INIS)

    In accordance with the present invention, uranium values are extracted from solid materials containing uranium in lower valence states than its hexavalent state comprising contacting the solid materials containing uranium with an alkaline leach solution containing the ionic species NH4+ and NO3- in an amount sufficient to convert at least a portion of the uranium in valence states lower than its hexavalent state to its hexavalent state. In another embodiment of the present invention, the aqueous alkaline leach solution is an aqueous solution of a carbonate selected from the group consisting of ammonium carbonate, ammonium bicarbonate and mixtures thereof. In a further embodiment, ionic species NO3- is supplied by an alkaline nitrate. In yet another embodiment of the present invention, the aqueous alkaline leach solution additionally contains at least one catalytic compound of a metal selected from the group consisting of copper, cobalt, iron, nickel, chromium and mixtures thereof adapted to assure the pesence of the ionic species Cu++, Co++, Fe+++, Ni++, Cr+++ and mixtures thereof, respectively, is present during the contacting of the solid materials containing uranium with the aqueous alkaline leach solution in an amount sufficient to catalyze the oxidation of at least a part of the uranium in valence states lower than its hexavalent state to its hexavalent state

  2. Leachate Concentrations of Ammonium, Nitrate, and Phosphorus as Affected by Nutrient Release From Four Different Types of Controlled-Release Fertilizers and Crop Development of Containerized Azaleas

    Science.gov (United States)

    Concentrations of ammonium, nitrate, and phosphorus in irrigation leachate were measured weekly over a 47-week period from a low-fertility, acid-based substrate into which four types of 12-month controlled-release fertilizers (Osmocote, Nutricote, Polyon, or Multicote) were incorporated. Containers ...

  3. CERIC AMMONIUM NITRATE CATALYZED ONE-POT SYNTHESIS OF NOVEL ISOXAZOLYL-HEXAHYDROQUININDOLINONES Cerammoniumnitrat KATALYSIERTEN ONE-POT Synthese von neuartigen Isoxazolyl-HEXAHYDROQUININDOLINONES

    Directory of Open Access Journals (Sweden)

    E. Rajanarendar, P. Venkateshwarlu, S. Rama Krishna

    2012-07-01

    Full Text Available The ceric ammonium nitrate (CAN catalyzed synthesis of novel isoxazolylhexahydroquinindolinones 4 were simply achieved upon the reaction of isoxazolyl-2-indolinone 1 with 3-amino-5-methyl-isoxazole 2 and dimedone 3 in ethanol with good yields from commercially available materials.

  4. Toxicity of Ambient Particulate Matter IV: Acute toxicity study in pulmonary hypertensive rats after exposure to model compounds for the secondary aerosol fraction of PM10 - ammonium bisulfate, ferrosulfate and nitrate

    NARCIS (Netherlands)

    Cassee FR; Boere AJF; Fokkens PHB; Dormans JAMA; Bree L van; Rombout PJA; LEO; LPI

    1999-01-01

    This (4th) report on the toxicity of ambient particulate matter (PM) presents effects of the model compounds for PM in ambient air - ammonium bisulfate, ammonium ferrosulfate and ammonium nitrate - on healthy rats and rats with monocrotaline-induced pulmonary hypertension (PH). The objective was bas

  5. Applications of nitrate and ammonium fertilizers alter soil nematode food webs in a continuous cucumber cropping system in Southwestern Sichuan, China

    Directory of Open Access Journals (Sweden)

    Kaiwen Pan

    2015-10-01

    Full Text Available Nitrate (NO3--N and ammonium (NH4+-N fertilizers are the main forms of chemical inorganic nitrogen fertilizers that are widely used in agro-ecosystem for high yield. However, the responses of soil nematode food web to different forms and rates of inorganic nitrogen fertilizers are not well understood. The objective of this study was to determine the responses of soil nematode food web to the applications of inorganic nitrogen fertilizers in a continuous cucumber (Cucumis sativus L. cropping system. Nitrate (NaNO3 and ammonium (NH4HCO3 fertilizers were applied to cucumber plants at the nitrogen (N rate of 0, 67.5, 135.0 and 202.5 kg N hm-2 before planting. It was conducted in a randomized complete block design with 4 replications at Huaizi village, Leshan district, Sichuan province, Southwestern China. The effects were analyzed at the stages of seedling, blooming and fruiting, respectively. The results indicated that the numbers of nematodes were significantly higher in soils with the addition of 67.5 kg N hm-2 than the control at the seedling and blooming stages. Nematode number strongly increased at the seedling stage and decreased at the blooming and fruiting stages in nitrate-treated soils compared to the ammonium-treated. The percentage of herbivores to total nematodes significantly decreased while that of bacterivores increased with a fertilizer rate less than 135 kg N hm-2 at the seedling and fruiting stages. Nitrate significantly reduced the percentage of herbivores, and increased that of bacterivores to total nematodes by comparison with ammonium at the blooming and fruiting stages. The application of nitrate significantly increased nematode diversity and evenness, and decreased dominance at the blooming stage relative to ammonium. Nitrate significantly decreased the values of channel index at the blooming stage and maturity index at the seedling stage in comparison with ammonium, respectively. Enrichment index and structural index

  6. Urea Ammonium Nitrate as the Carrier for Herbicides in Winter Wheat

    OpenAIRE

    Nader Soltani; Christy Shropshire; Peter H. Sikkema

    2012-01-01

    Urea ammonium nitrogen can be used as a carrier for herbicides to provide growers with an option for the control of broadleaf weeds and spraying nitrogen fertilizer in one pass in winter wheat. Field studies (six in total) were seeded in the autumn of 2005, 2006 and 2007 at Exeter and Ridgetown, Ontario, Canada to determine if UAN can be used as a carrier for bromoxynil/MCPA, dichlorprop/2,4-D, dicamba/MCPA/mecoprop, or thifensulfuron/tribenuron applied postemergence (POST) at three applicati...

  7. Effects of temperature and light intensity on the uptake and assimilation of 15N-labeled ammonium and nitrate in Indica and Japonica rice plants

    International Nuclear Information System (INIS)

    The effects of various environmental condition such as temperature and light intensity on the uptake and assimilation of ammonium and nitrate in 4-week-old Indica and Japonica rice plants were studied using the 15N tracer technique. Both temperature and light intensity profoundly affected the uptake and assimilation of ammonium and nitrate, and the effects were more apparent in the utilization of nitrate by both Indica and Japonica rice plants. The uptake as well as assimilation of the two forms of nitrogen were greatly inhibited at low temperature and low light intensity. On the other hand, although no significant difference in the effects of environmental conditions on the utilization of ammonium was observed between the Indica and Japonica rice plants, the former were more sensitive than the latter in the utilization of nitrate. At high temperature and high light intensity, the Indica rice plants absorbed, reduced, and assimilated nitrate more effectively than the Japonica, and this effect disappeared when the temperature or light intensity was reduced. (author)

  8. Study on Modification of Ammonium Nitrate by Gemini Surfactants%Gemini表面活性剂对硝酸铵的改性研究

    Institute of Scientific and Technical Information of China (English)

    叶志文; 吕春绪; 刘祖亮

    2004-01-01

      本文通过对普通表面活性剂、Gemini表面活性剂分别处理的改性硝酸铵进行电镜扫描、孔径、孔容分布、粒径分布、比表面积、抗吸湿结块性及爆炸性能的实验研究,所得结果表明:同普通表面活性剂处理的改性硝酸铵相比,Gemini改性硝酸铵的晶形不规则、比表面积大,富含气孔,更多的有效孔径处于介孔范围,有较小的粒径范围,并且有良好的抗吸湿结块性,用其制得的粉状工业炸药具有更好的物理性能和爆炸性能。%  In this paper, ammonium nitrate is modified by separately treated with common surfactants and Gemini surfactants for comparison. Both the modified ammonium nitrate samples are examined by SEM and other testing methods for pore radius and pore volume's distribution, particle size’s distribution, specific surface area, anti-hygroscopocity and anti-caking properties. the results show that, compared with the modified ammonium nitrate treated by common surfactants, the modified ammonium nitrate treated with Gemini surfactants has better properties such as disproportionate crystal shape, larger specific surface area, containing great number of gas-pocket with most of valid pore radius in range of meso-pore, smaller range of particle size and better performances of anti-hygroscopicity and anti-caking. The powder industrial explosive made from the modified ammonium nitrate treated by Gemini surfactants have better properties of physics and explosion.

  9. Effect of Nitrate Uptake Kinetic with Different Ratios of Ammonium and Nitrate in Banana Seedlings%不同铵硝配比对香蕉幼苗硝态氮吸收动力学特征影响

    Institute of Scientific and Technical Information of China (English)

    王岚; 王伟; 黄承和; 常春荣

    2012-01-01

    The characteristics of nitrate uptake kinetic in the solution of five ratios of ammonium and nitrate by modified depleting way treated with 0.2 mtnol/L CaSO4 solution for three days were studied to discover the ammonium and' nitrate nutrition properties of banana seedlings. The result showed that the nitrate uptake kinetic characteristics of all treatments with five ratios of ammonium and nitrate followed the enzyme kinetic model of Michaelis-Menten. Increasing ammonium ratio remarkably influenced Vmax. and Kmi would be reduced more to the Hoagland solution adding 10% ammonium than that in placement of 10% ammonium with 10% nitrate, although Kn had no distinct difference between these two treatments. The nitrate uptake rate would be reduced in soil of 100% nitrate treated with increasing ammonium ratios. The nitrate affinity, would be decreased treated with 10% more ammonium, while that for the 25% ammonium treatment was in the opposite direction. The nitrate uptake for banana seedlings belonged to low affinity system.%将香蕉苗移植到0.2 mmol/L CaSO4溶液中饥饿3d,采用改进耗竭法研究了香蕉幼苗期在5种铵硝配比营养液中的硝态氮的吸收动力学特征,以探讨香蕉铵硝营养特点.结果表明,香蕉幼苗所有铵硝配比处理的硝态氮吸收曲线特征均符合Michaelis-Menten酶动力学模型的描述.加铵不仅显著影响香蕉幼苗硝态氮吸收动力学参数Vax,对Km的影响也达显著水平.在霍格兰营养液的基础上直接添加10%NH4+-N比将10%NO3-N用NIH4+-N替换更能降低香蕉对硝态氮的吸收速率,但这两种处理对Km的影响不显著.在100%硝态氮的基础上,增铵降低了香蕉对硝态氮的吸收速率,增10%NH4+-N降低香蕉对硝态氮的亲和力,增25% NH+4-N对香蕉对硝态氮的亲和力的影响则相反.在本实验条件下,香蕉硝态氮吸收系统属于低亲和吸收系统.

  10. Soil nematode responses to fertilization with ammonium nitrate after six years of unfertilized apple orchard

    Directory of Open Access Journals (Sweden)

    Claudia V. Azpilicueta

    2014-03-01

    Full Text Available A nematode community was used as a bioindicator of changes in agroecosystems caused by fertilization. The effect of applying nitrogen (N fertilizer on a soil nematode community structure was studied in a soil which had not been fertilized for six years in the Rio Negro Valley, Argentina. Treatments were: i 100 kg N ha-1 (N100; ii 200 kg N ha-1 (N200; in each case 50% of the dosage was applied at the time of petal fall and 50% at fruit harvest in 2004/2005, 2005/2006, 2006/2007 growing seasons; and iii control with no fertilizer (N0. Soil samples were collected in the 0 to 30 cm soil layer in October, November, April and July in each growing season. The number of bacterivores increased in N200 compared to N0. Cephalobidae were present in greater numbers in N200 than in N100 and N0. Predator abundance was lower under N200, after the first N application in each growing season. The ratio of fungivores to bacterivores (F/B was 0.21, 0.3 and 0.41 in N200, N100 and N0, respectively. N200 resulted in a community with a lower maturity index (MI than N0. Structure index (SI was lower in N200 than N100 and N0. The enrichment index (EI was less sensitive at detecting fertilizer effects. In November and April, soil nitrate concentrations were higher in N200 than in N100 and N0. Soil nitrate concentration was positively correlated with EI and negatively with MI, SI and F/B. N200 affected the trophic structure of the nematode community consistent with a less stable soil system.

  11. Isotopic characterization of nitrate, ammonium and sulfate in stack PM2.5 emissions in the Athabasca Oil Sands Region, Alberta, Canada

    Science.gov (United States)

    Proemse, Bernadette C.; Mayer, Bernhard; Chow, Judith C.; Watson, John G.

    2012-12-01

    Stable isotope techniques may be a suitable tool for tracing industrial emissions in the atmosphere and the environment provided that the isotopic compositions of industrial emissions are distinct. We determined the isotopic compositions of nitrate, ammonium and sulfate in PM2.5 emitted from two industrial stacks at a large upgrader site in the Athabasca oil sands region (AOSR), northeastern Alberta, Canada, and compared them to the nitrogen and sulfur isotopic compositions of source materials and upgrading by-products. We found distinct isotopic compositions of nitrate and ammonium in PM2.5 compared to those reported for atmospheric nitrate and ammonium in the literature. Nitrate in PM2.5 had δ15N values of 9.4‰ (Stack A) and 16.1 ± 1.2‰ (Stack B) that were significantly enriched in 15N compared to the feedstock materials (˜2.5‰), by-products of upgrading (-0.3-1.3‰), and atmospheric N2 (0‰). δ15N of ammonium in PM2.5 showed a large range with values between - 4.5 to +20.1‰ (Stack B). We report the first measurements of the triple oxygen isotopic composition of industrial emitted nitrate. Nitrate emitted as PM2.5 is not mass-independently enriched in 17O resulting in Δ17O = 0.5 ± 0.9‰ (Stack B) and is therefore distinct from atmospheric nitrate, constituting an excellent indicator of industrial derived nitrate. δ18O values of nitrate in PM2.5 (36.0 and 17.6 ± 1.8‰ for Stack A and B, respectively) were also significantly lower than δ18O values of atmospheric nitrates and hence isotopically distinct. δ34S values of sulfate in PM2.5 were with 7.3 ± 0.3‰ (Stack A) and 9.4 ± 2.0‰ (Stack B) slightly enriched in 34S compared to δ34S in bitumen (4.3 ± 0.3‰) and coke (3.9 ± 0.2‰). δ18O values of sulfate in PM2.5 were 18.9 ± 2.9‰ and 14.2 ± 2.8‰ for Stack A and Stack B, respectively. The isotopic composition of sulfate in PM2.5 was not sufficiently different from δ34S and δ18O values of sulfate in long-range atmospheric

  12. Assimilation of 15N-labelled urea nitrogen and ammonium nitrate nitrogen by plants in case of root and non-root fertilization

    International Nuclear Information System (INIS)

    Assimilation of 15N labeled urea and ammonium nitrate in root and foliar application by spring wheat and barley has been studied during 1970-1973 period in a series of vegetative experiments at the Department of Agrochemistry, Timiryazev Agricultural Academy, and at D.N. Pryanishnikov Experimental Agrochemical Station. Additional fertilizer nitrogen applied at later ontogenesis stages (flowering and milky ripeness) is utilized mostly for protein synthesis in developing grains, thus leading to a significant increase in the relative grain protein content. A transfer of a part of nitrogen from the main ortion of fertilizer at later stages of nitrition results, at the same time, in a lower yield. Nitrogen utilization degree of urea and ammonium nitrate, when introduced before sowing or at the flowering stage is similar but in the latter case, however, additional assimilation of soil nitrogen is lower. The assimilation rate of nitrogen in root application is the lower the later the fertilizer is applied. When ammonium nitrate is additionally applied as nutrition to barley at the milky ripeness stage, ammonia and nitrate nitrogen are assimilated at the same rate and to the same extent but ammonia nitrogen is more rapidly used for protein synthesis and the rate of its transfer to the developing grains is higher. The rate of nitrogen assimilation at plant is much higher in foliar than in root application. Wheat utilizes more urea nitrogen at the flowering stage when root application is used but at the milky ripeness stage foliar application is more effective

  13. Impact of orchard and tillage management practices on soil leaching of atrazine, potassium, magnesium, manganese, iron, ammonium, nitrates and phosphates

    Science.gov (United States)

    Szajdak, L.; Lipiec, J.; Siczek, A.; Kotowska, U.; Nosalewicz, A.

    2009-04-01

    The experiments were carried out on an Orthic Luvisol developed from loess, over limestone, at the experimental field of Lublin Agricultural University in Felin (51o15'N, 22o35'E), Poland. The investigation deals with the problems of leaching's rate of atrazine (2-chloro-4-ethylamino-6-isopropylamino-1,2,3-triazine), potassium, magnesium, manganese, iron, ammonium, nitrates and phosphates from two management systems of soil: (i) conventionally tilled field with main tillage operations including stubble cultivator (10 cm) + harrowing followed by mouldboard ploughing to 20 cm depth, and crop rotation including selected cereals, root crops and papillionaceous crops, (ii) 35-year-old apple orchard field (100x200m) with a permanent sward that was mown in the inter-rows during the growing season. The conventionally tilled plot was under the current management practice for approximately 30 years. Field sites were close to each other (about 150 m). Core samples of 100 cm3 volume and 5 cm diameter were taken from two depths 0-10 cm and 10-20 cm, and were used to determine the soil water characteristic curve. It was observed that management practices impacted on the physic-chemical properties of soils. pH (in H2O) in tilled soil ranged from 5.80 to 5.91. However soil of orchard soil revealed higher values of pH than tilled soil and ranged from 6.36 to 6.40. The content of organic carbon for tilled soil ranged from 1.13 to 1.17%, but in orchard soil from 1.59 to 1.77%. Tillled soil showed broader range of bulk density 1.38-1.62 mg m-3, than orchard soil 1.33-134 mg m-3. The first-order kinetic reaction model was fitted to the experimental atrazine, potassium, magnesium, manganese, iron, nitrates, ammonium and phosphates leaching vs. time data. The concentrations of leached chemical compounds revealed linear curves. The correlation coefficients ranged from -0.873 to -0.993. The first-order reaction constants measured for the orchard soils were from 3.8 to 19 times higher than

  14. Experimental additions of aluminum sulfate and ammonium nitrate to in situ mesocosms to reduce cyanobacterial biovolume and microcystin concentration

    Science.gov (United States)

    Harris, Ted D.; Wilhelm, Frank M.; Graham, Jennifer L.; Loftin, Keith A.

    2014-01-01

    Recent studies suggest that nitrogen additions to increase the total nitrogen:total phosphorus (TN:TP) ratio may reduce cyanobacterial biovolume and microcystin concentration in reservoirs. In systems where TP is >100 μg/L, however, nitrogen additions to increase the TN:TP ratio could cause ammonia, nitrate, or nitrite toxicity to terrestrial and aquatic organisms. Reducing phosphorus via aluminum sulfate (alum) may be needed prior to nitrogen additions aimed at increasing the TN:TP ratio. We experimentally tested this sequential management approach in large in situ mesocosms (70.7 m3) to examine effects on cyanobacteria and microcystin concentration. Because alum removes nutrients and most seston from the water column, alum treatment reduced both TN and TP, leaving post-treatment TN:TP ratios similar to pre-treatment ratios. Cyanobacterial biovolume was reduced after alum addition, but the percent composition (i.e., relative) cyanobacterial abundance remained unchanged. A single ammonium nitrate (nitrogen) addition increased the TN:TP ratio 7-fold. After the TN:TP ratio was >50 (by weight), cyanobacterial biovolume and abundance were reduced, and chrysophyte and cryptophyte biovolume and abundance increased compared to the alum treatment. Microcystin was not detectable until the TN:TP ratio was <50. Although both treatments reduced cyanobacteria, only the nitrogen treatment seemed to stimulate energy flow from primary producers to zooplankton, which suggests that combining alum and nitrogen treatments may be a viable in-lake management strategy to reduce cyanobacteria and possibly microcystin concentrations in high-phosphorus systems. Additional studies are needed to define best management practices before combined alum and nitrogen additions are implemented as a reservoir management strategy.

  15. Improved diffusion technique for 15N:14N analysis of ammonium and nitrate from aqueous samples by stable isotope spectrometry

    International Nuclear Information System (INIS)

    Nitrogen (N) isotope ratio mass spectrometry (IRMS) by Dumas combustion and continuous flow mass spectrometry has become a wide-spread tool for the studies of N turnover. The speed and labor efficiency of 15N determinations from aqueous solutions such as soil solutions or soil extracts are often limited by sample preparation. Several procedures for the conversion of dissolved ammonium (NH4+) or nitrate NO3- to gaseous ammonia and its subsequent trapping in acidified traps have been elaborated in the last decades. They are based on the use of acidified filters kept either above the respective solution or in floating PTFE envelopes. In this paper, we present an improved diffusion method with a fixed PTFE trap. The diffusion containers are continuously kept in a vertical rotary shaker. Quantitative diffusion can thus be achieved in only three days. For solutions with NH4+ levels of only 1 mg N kg-1 and NO3- concentrations of 12 mg N kg-1, recovery rates of 98.8-102% were obtained. By addition of 15N labeled and non-labeled NH4+ and NO3- it was shown that no cross-contamination from NH4+ to NO3- or vice versa takes place even when one form is labeled to more than 1 at %15N while the other form has natural 15N content. The method requires no intermediate step of ammonia volatilization before NO3- conversion

  16. Burning Characteristics of Ammonium-Nitrate-Based Composite Propellants with a Hydroxyl-Terminated Polybutadiene/Polytetrahydrofuran Blend Binder

    Directory of Open Access Journals (Sweden)

    Makoto Kohga

    2012-01-01

    Full Text Available Ammonium-nitrate-(AN- based composite propellants prepared with a hydroxyl-terminated polybutadiene (HTPB/polytetrahydrofuran (PTHF blend binder have unique thermal decomposition characteristics. In this study, the burning characteristics of AN/HTPB/PTHF propellants are investigated. The specific impulse and adiabatic flame temperature of an AN-based propellant theoretically increases with an increase in the proportion of PTHF in the HTPB/PTHF blend. With an AN/HTPB propellant, a solid residue is left on the burning surface of the propellant, and the shape of this residue is similar to that of the propellant. On the other hand, an AN/HTPB/PTHF propellant does not leave a solid residue. The burning rates of the AN/HTPB/PTHF propellant are not markedly different from those of the AN/HTPB propellant because some of the liquefied HTPB/PTHF binder cover the burning surface and impede decomposition and combustion. The burning rates of an AN/HTPB/PTHF propellant with a burning catalyst are higher than those of an AN/HTPB propellant supplemented with a catalyst. The beneficial effect of the blend binder on the burning characteristics is clarified upon the addition of a catalyst. The catalyst suppresses the negative influence of the liquefied binder that covers the burning surface. Thus, HTPB/PTHF blend binders are useful in improving the performance of AN-based propellants.

  17. Direct and indirect effects of ammonia, ammonium and nitrate on phosphatase activity and carbon fluxes from decomposing litter in peatland

    International Nuclear Information System (INIS)

    Here we investigate the response of soils and litter to 5 years of experimental additions of ammonium (NH4), nitrate (NO3), and ammonia (NH3) to an ombrotrophic peatland. We test the importance of direct (via soil) and indirect (via litter) effects on phosphatase activity and efflux of CO2. We also determined how species representing different functional types responded to the nitrogen treatments. Our results demonstrate that additions of NO3, NH4 and NH3 all stimulated phosphatase activity but the effects were dependent on species of litter and mechanism (direct or indirect). Deposition of NH3 had no effect on efflux of CO2 from Calluna vulgaris litter, despite it showing signs of stress in the field, whereas both NO3 and NH4 reduced CO2 fluxes. Our results show that the collective impacts on peatlands of the three principal forms of nitrogen in atmospheric deposition are a result of differential effects and mechanisms on individual components. - We found that nitrogen deposition affects microbial activity associated with litter through both indirect and direct mechanisms, but these effects were dependent on the chemical form of inorganic nitrogen compounds.

  18. nfluences of ammonium-nitrate, food waste compost and bacterial fertilizer on soluble soil nitrogen forms and on the growth of carrot (Daucus Carota L.

    Directory of Open Access Journals (Sweden)

    Andrea Balla Kovács

    2014-04-01

    Full Text Available This paper reports a greenhouse study to compare the effects of food waste compost, bacterial fertilizer and their combination with the effect of mineral fertilizer on yield of carrot and the available nutrient content of soils. The study was conducted on calcareous chernozem and acidic sandy soils and consisted of 8 treatments in a randomized complete block design with four replications. The NH4NO3 resulted in reduced growing of carrot plant in sandy soil, and the treatment effect of mineral fertilizer was not observed significantly in chernozem soil. Sandy soil showed higher response of growth of carrot to food waste compost fertilization than chernozem soil. Sole application of EM-1 bacterial fertilizer did not have marked effect on yield parameters and sizes of roots. When EM-1 bacterial fertilizer was applied together with ammonium-nitrate or with compost in chernozem soil, the weights of roots and the sizes of roots in some cases became higher compared to the values of appropriate treatments without inoculation. In sandy soil the diameter of roots slightly increased when EM-1 bacterial fertilizer was applied with ammonium-nitrate and with ammonium-nitrate+compost combination compared to appropriate treatment without inoculation. In chernozem soil the maximum weights and sizes of roots were achieved with the combined treatment of ammonium-nitrate+compost+EM-1 bacterial fertilizer and in sandy soil with compost treatment. Our results of soluble nitrogen content of soils are in good agreement with yield parameters of carrot. Results suggest that food waste compost could be a good substitute for mineral fertilizer application in carrot production mainly in sandy soil. EM-1 bacterial fertilizer did not cause marked effect on yield and yield parameters of carrot plant, but its combination with other fertilizers promises a little bit higher yield or plant available nutrient in the soil. These effects do not clear exactly, so further studies are

  19. Studies on the production in small scale batch process of the sinterable uranium dioxide by uranyl nitrate solution-ammonium polyuranate-uranium dioxide route

    International Nuclear Information System (INIS)

    The studies on the production of sinterable uranium dioxide by means of precipiation of ammonium polyuranate with NH3 aq. from the aqueous uranyl nitrate solution and on its calcination and reduction with hydrogen were carried out. The influence of the precipiation parameters of ammonium polyuranate on its and uranium dioxide physico-chemical properties and their reproducibility as well as the possibilities to obtain these powders in the batch small scale process were examined. The physico-chemical properties of powders, impurities contents and the ability for pressing and sintering were determined. As a reult the most advantageous conditions of the precipitation has been established. It was found possible to obtain both ammonium polyuranate and uranium dioxide powders in a state o high purity with reproducible physico-chemical properties. The specific density of sintered pellets was higher than 94% of the theoretical density. (author)

  20. Rapid Determination of Total Nitrogen, Ammonium and Nitrate Nitrogen in Vinegar Residue Growing Substrates using Near-Infrared Spectroscopy

    Directory of Open Access Journals (Sweden)

    Yongli Zhu

    2013-10-01

    Full Text Available The objective of this study was to investigate the feasibility of using Near-Infrared Spectroscopy (NIRS to determine the total nitrogen, ammonium and nitrate nitrogen in growing substrates of vinegar residues. Samples of 106 substrates were collected from the cultivation experiments of vinegar residue substrates. Spectra of the visible and near infrared region (350-2500 nm were obtained for all samples after drying and grinding (variant A or in a moist state (variant B. Across validation was carried out using a partial least square method which was based on the entire spectra. For parameters TN, NO3- and NH4+, precisions of the calibration and prediction models were inconsistent between variant A and B. For variant A, the prediction coefficient (r, Root Mean Squared Error of Cross-Validation (RMSECV and the ratio of standard deviation and RMSECV (RSC were 0.97, 0.64 g/kg and 4.4 for TN, 0.58, 15.4 mg/kg and 1.2 for NO3-, 0.79, 0.75 g/kg and 1.5 for NH4+, respectively. For moist samples, the r, RMSECV and RSC were 0.79, 1.81 g/kg and 1.6 for TN, 0.85, 9.95 mg/kg and 1.9 for NO 3-, 0.92, 0.45 g/kg and 2.5 for NH 4+, respectively. The results indicate a marked usefulness of NIRS in the nitrogen assessment and management of growing substrates, especially for TN and NH4. However, further research is needed to improve the prediction precision of calibration models by enlarging the number of samples and using other growing substrates.

  1. Effects of elevated CO2 concentration on growth and water usage of tomato seedlings under different ammonium/nitrate ratios

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    Increasing atmospheric CO2 concentration is generally expected to enhance photosynthesis and growth of agricultural C3 vegetable crops,and therefore results in an increase in crop yield.However,little is known about the combined effect of elevated CO2 and N species on plant growth and development.Two growth-chamber experiments were conducted to determine the effects of NH4+/NO3- ratio and elevated CO2 concentration on the physiological development and water use of tomato seedlings.Tomato was grown for 45 d in containers with nutrient solutions varying in NH4+/NO3- ratios and CO2 concentrations in growth chambers.Results showed that plant height,stem thickness,total dry weight,dry weight of the leaves,stems and roots,G value (total plant dry weight/seedling days),chlorophyll content,photosynthetic rate,leaf-level and whole plant-level water use efficiency and cumulative water consumption of tomato seedlings were increased with increasing proportion of NO3- in nutrient solutions in the elevated CO2 treatment.Plant biomass,plant height,stem thickness and photosynthetic rate were 67%,22%,24% and 55% higher at elevated CO2 concentration than at ambient CO2 concentration,depending on the values of NH4+/NO3- ratio.These results indicated that elevating CO2 concentration did not mitigate the adverse effects of 100% NH4+-N (in nutrient solution) on the tomato seedlings.At both CO2 levels,NH4+/NO3- ratios of nutrient solutions strongly influenced almost every measure of plant performance,and nitrate-fed plants attained a greater biomass production,as compared to ammonium-fed plants.These phenomena seem to be related to the coordinated regulation of photosynthetic rate and cumulative water consumption of tomato seedlings.

  2. Long-Term Distribution and Transport of Nitrate and Ammonium Within a Groundwater Sewage Plume, Cape Cod, MA, After Removal of the Contaminant Source.

    Science.gov (United States)

    Repert, D. A.; Smith, R. L.

    2002-12-01

    Disposal of treated sewage for 60 yrs. onto infiltration beds at a site on Cape Cod, MA produced a groundwater contaminant plume >6 km long. The plume was characterized by an anoxic ammonium-containing core, surrounded by an oxic-suboxic outer zone within the sand and gravel aquifer. In Dec. 1995 the sewage treatment facility ceased operation. A long-term study to characterize the distribution of sewage plume constituents was conducted along a 500 m-long transect (source to 3 yrs. groundwater travel distance). Prior to sewage-disposal cessation, total inorganic N within 30 m vertical profiles decreased from 6.6 moles N/m2 (92% NO3-, 8% NH4+) at the point of discharge to 3.3 moles N/m2 (77% NO3-, 23% NH4+) at the furthest point along the transect. Post-cessation nitrate concentrations increased within the first 6 mo. and then gradually decreased. The nitrate decrease was accompanied by an initial nitrite increase, an indication that denitrification was reducing nitrate after the oxygenated sewage discharge was discontinued. There was also an apparent increase in ammonium concentration in the first 6 mo. after cessation. Previous laboratory experiments on pre-cessation cores showed that nitrification was important in converting sorbed ammonium to nitrate under the sewage beds. However, with the removal of the oxygenated sewage source, nitrification ceased, allowing ammonium to initially increase. This increase was correlated with dissolved organic carbon concentrations within the groundwater. Ammonium concentrations decreased dramatically after a year, but subsequently increased in the core of the plume to pre-cessation levels through mineralization of organic N. Recent laboratory core experiments and extractions show that there is a large pool of sorbed organic carbon, although dissolved organic carbon concentrations have been consistently less than 3 mg/L for 6 yrs. Seven yrs. after cessation of the sewage disposal, there is still a significant amount (0.6 moles N

  3. 现场总线技术及其在硝铵装置中的应用%Fieldbus Technology and Its Application in Ammonium Nitrate Unit

    Institute of Scientific and Technical Information of China (English)

    何联合

    2001-01-01

    阐述了现场总线的特点、发展、设计和组态方法及其在硝铵装置中的具体应用;分析了现场总线系统的经济效益和社会效益。%The characteristic,history,design and configuration method of fieldbus system and its application in ammonium nitrate unit are introduced. The economic and social benefits due to the fieldbus system are analyzed.

  4. The attempt to explain the various reaktions of rape and corn plants on the nitrogen usee in the ammonium or nitrate forms

    OpenAIRE

    Zofia Uziak; Edward Borowski; Zbyszek Blamowski

    2013-01-01

    The reaction of the rape and corn plants on the nitrogen applied in the form NO3- or NH4+ was studied under the controlled conditions. The ammonium ions with rape markedly lowered the growth rate, the intensity of photosynthesis and biomass yield, with relation to the plants fertilized with nitrates. With corn the effect of both N-forms was similar and positive. The biomass of the rape using NH4+, with relation to the plants fertilized with NO3- showed lower content of total N, and protein N,...

  5. Electrochemical preparation of few layer-graphene nanosheets via reduction of oriented exfoliated graphene oxide thin films in acetamide-urea-ammonium nitrate melt under ambient conditions

    International Nuclear Information System (INIS)

    Electrochemical reduction of exfoliated graphene oxide, prepared from pre-exfoliated graphite, in acetamide-urea-ammonium nitrate ternary eutectic melt results in few layer-graphene thin films. Negatively charged exfoliated graphene oxide is attached to positively charged cystamine monolyer self-assembled on a gold surface. Electrochemical reduction of the oriented graphene oxide film is carried out in a room temperature, ternary molten electrolyte. The reduced film is characterized by atomic force microscopy (AFM), conductive AFM, Fourier-transform infrared spectroscopy and Raman spectroscopy. Ternary eutectic melt is found to be a suitable medium for the regulated reduction of graphene oxide to reduced graphene oxide-based sheets on conducting surfaces.

  6. Glutamine nitrogen and ammonium nitrogen supplied as a nitrogen source is not converted into nitrate nitrogen of plant tissues of hydroponically grown pak-choi (Brassica chinensis L.).

    Science.gov (United States)

    Wang, H-J; Wu, L-H; Tao, Q-N; Miller, D D; Welch, R M

    2009-03-01

    Many vegetables, especially leafy vegetables, accumulate NO(-) (3)-N in their edible portions. High nitrate levels in vegetables constitute a health hazard, such as cancers and blue baby syndrome. The aim of this study was to determine if (1) ammonium nitrogen (NH(+) (4)-N) and glutamine-nitrogen (Gln-N) absorbed by plant roots is converted into nitrate-nitrogen of pak-choi (Brassica chinensis L.) tissues, and (2) if nitrate-nitrogen (NO(-) (3)-N) accumulation and concentration of pak-choi tissues linearly increase with increasing NO(-) (3)-N supply when grown in nutrient solution. In experiment 1, 4 different nitrogen treatments (no nitrogen, NH(+) (4)-N, Gln-N, and NO(-) (3)-N) with equal total N concentrations in treatments with added N were applied under sterile nutrient medium culture conditions. In experiment 2, 5 concentrations of N (from 0 to 48 mM), supplied as NO(-) (3)-N in the nutrient solution, were tested. The results showed that Gln-N and NH(+) (4)-N added to the nutrient media were not converted into nitrate-nitrogen of plant tissues. Also, NO(-) (3)-N accumulation in the pak-choi tissues was the highest when plants were supplied 24 mM NO(-) (3)-N in the media. The NO(-) (3)-N concentration in plant tissues was quadratically correlated to the NO(-) (3)-N concentration supplied in the nutrient solution. PMID:19323774

  7. Stand-off imaging Raman spectroscopy for forensic analysis of post-blast scenes: trace detection of ammonium nitrate and 2,4,6-trinitrotoluene

    Science.gov (United States)

    Ceco, Ema; Önnerud, Hans; Menning, Dennis; Gilljam, John L.; Bââth, Petra; Östmark, Henric

    2014-05-01

    The following paper presents a realistic forensic capability test of an imaging Raman spectroscopy based demonstrator system, developed at FOI, the Swedish Defence Research Agency. The system uses a 532 nm laser to irradiate a surface of 25×25mm. The backscattered radiation from the surface is collected by an 8" telescope with subsequent optical system, and is finally imaged onto an ICCD camera. We present here an explosives trace analysis study of samples collected from a realistic scenario after a detonation. A left-behind 5 kg IED, based on ammonium nitrate with a TNT (2,4,6-trinitrotoluene) booster, was detonated in a plastic garbage bin. Aluminum sample plates were mounted vertically on a holder approximately 6 m from the point of detonation. Minutes after the detonation, the samples were analyzed with stand-off imaging Raman spectroscopy from a distance of 10 m. Trace amounts could be detected from the secondary explosive (ammonium nitrate with an analysis time of 1 min. Measurement results also indicated detection of residues from the booster (TNT). The sample plates were subsequently swabbed and analyzed with HPLC and GC-MS analyses to confirm the results from the stand-off imaging Raman system. The presented findings indicate that it is possible to determine the type of explosive used in an IED from a distance, within minutes after the attack, and without tampering with physical evidence at the crime scene.

  8. Sulfate-nitrate-ammonium aerosols over China: response to 2000–2015 emission changes of sulfur dioxide, nitrogen oxides, and ammonia

    Directory of Open Access Journals (Sweden)

    Y. Wang

    2013-03-01

    Full Text Available We use a chemical transport model to examine the change of sulfate-nitrate-ammonium (SNA aerosols over China due to anthropogenic emission changes of their precursors (SO2, NOx and NH3 from 2000 to 2015. From 2000 to 2006, annual mean SNA concentrations increased by about 60% over China as a result of the 60% and 80% increases in SO2 and NOx emissions. During this period, sulfate is the dominant component of SNA over South China (SC and Sichuan Basin (SCB, while nitrate and sulfate contribute equally over North China (NC. Based on emission reduction targets in the 12th (2011–2015 Five-Year Plan (FYP, China's total SO2 and NOx emissions are projected to change by −16% and +16% from 2006 to 2015, respectively. The amount of NH3 emissions in 2015 is uncertain, given the lack of sufficient information on the past and present levels of NH3 emissions in China. With no change in NH3 emissions, SNA mass concentrations in 2015 will decrease over SCB and SC compared to their 2006 levels, but increase over NC where the magnitude of nitrate increase exceeds that of sulfate reduction. This suggests that the SO2 emission reduction target set by the 12th FYP, although effective in reducing SNA over SC and SCB, will not be successful over NC, for which NOx emission control needs to be strengthened. If NH3 emissions are allowed to keep their recent growth rate and increase by +16% from 2006 to 2015, the benefit of SO2 reduction will be completely offset over all of China due to the significant increase of nitrate, demonstrating the critical role of NH3 in regulating nitrate. The effective strategy to control SNA and hence PM2.5 pollution over China should thus be based on improving understanding of current NH3 emissions and putting more emphasis on controlling NH3 emissions in the future.

  9. Effect of additives with common cation on the radiolysis of ammonium, sodium and potassium nitrates in admixtures

    International Nuclear Information System (INIS)

    Gamma radiolysis of admixtures of NH4NO3, NaNO3 and KNO3 with additive salts having common cation has been studied over a wide range of nitrate salt concentration and absorbed dose. Radiolytic decomposition of nitrate salt depends on the concentration of nitrate in the admixture as well as the total absorbed dose. G(NO2-) values calculated on the basis of electron fraction of the nitrate salt decrease with the increase in mol% of the nitrate salt in somewhat exponential manner. In (NaNO3 + Na2SO4) and (KNO3 + KX, where X = Cl, Br, I) systems decomposition was found to increase linearly with the absorbed dose in the composition range of 20-100 mol%. The additives seem to exhibit sensitization effect causing extra decomposition by the energy transfer process in solid state. The efficiency of energy transfer depends on the nature of added salt, concentration of the nitrate in admixture and absorbed dose. (author)

  10. Nitrogen nutrition of Canna indica: Effects of ammonium versus nitrate on growth, biomass allocation, photosynthesis, nitrate reductase activity and N uptake rates

    DEFF Research Database (Denmark)

    Konnerup, Dennis; Brix, Hans

    2010-01-01

    The effects of inorganic nitrogen (N) source (NH4+, NO3- or both) on growth, biomass allocation, photosynthesis, N uptake rate, nitrate reductase activity and mineral composition of Canna indica were studied in hydroponic culture. The relative growth rates (0.05-0.06 g g-1 d-1), biomass allocation...

  11. Effect of nitrogen form (ammonium and nitrate on quantitative and qualitative indices of Tulipa gesneriana cv. Apricot parrot

    Directory of Open Access Journals (Sweden)

    H. Abbasi

    2015-11-01

    Full Text Available Effects of nutrient solutions on quantitative and qualitative indices of tulip (Tulipa gesneriana cv. Apricot parrot were studied in a completely randomized design with 5 nutrient solutions, 4 experimental units and 3 replications. Plants were fed with five nutrient solutions (S1, S2, S3, S4 and S5 having NH4+-N/total N ratios of 0, 0.038, 0.074, 0.11 and 0.14, respectively. All nutrient solutions had similar concentrations of mineral elements. The five treatments consisted of 2.5 meq/L total N, and concentration of all the nutrients was 8.4 meq/L. Based on the results, increasing the ammonium level in nutrient solutions decreased N and total protein storage in the bulbs, but increased N concentration in the shoots. The ammonium level had no significant effect on potassium concentration of shoots, but increased phosphorus concentration in the shoots. Maximum calcium and magnesium concentration in shoots, wet weight and length and diameter of flowering stem were obtained in plants fed with S2 solution. Increasing the ammonium level increased number of bulblets, but decreased their size. Increasing the ammonium level decreased time to flowering of bulbs. The highest longevity of cut flowers was observed in plants fed with S2 solution. In general, based on the results of this research, with increasing the ammonium level in the nutrients solution, the qualitative traits of tulip, such as length and diameter of flowering stem, were increased, but longevity of cut flowers and number of produced bulblets were decreased.

  12. Studies of Decomposition rate and release of nutrients Ammonium, Nitrates, Nitrites, and Phosphates ions during the decomposition of Oryza coarctata in the laboratory experiment

    Directory of Open Access Journals (Sweden)

    Zafar Farooqui

    2013-09-01

    Full Text Available The vegetation, other than the mangroves in Indus delta, for example Oryza coarctata is also the source of nutrients for the adjacent coastal environment. The O. coarctata is the major vegetation on the tidal mudflatds of Keti-Bunder (Hajambro creek, Indus delta, other than the Avicennia marina and Rhizophora mucronata planted mangrove forest. This is the first report of decomposition rates of O. coarctata in the laboratory. The decomposition of O. coarctata. was conducted to evaluate the nutrients (ammonium, nitrate, nitrites, phosphates during the decomposition. The decomposition rate was more rapid during this early phase and O. coarctata. decomposed up to 40 % during the first 7 days. Afterwards, the Oryza sp. decomposed slowly and gradually and remained up to 40% of the dry mass. Therefore, about 60% of the organic matter present in the O. coarctata can decompose completely in the aerobic conditions of the aquatic environment. The ammonium ions concentration was found 2.75 μM/L at 7th day and highest value was 6.38 μM/L at 124th day of experiment. So the amount of ammonium ions increased during the phase of decomposition. The nitrate ions concentration was 1.95 μM/L at 7th day and increased to 2.71 μM/L at 15th day of decomposition, and afterwards the concentration of nitrate decreased gradually and lowest value 0.129 μM/L was recorded in the last day of the experiment. The nitrite ions concentration was found 1.80 μM/L and gradually increased to 3.33 μM/L at 60th day and the lowest value was 3.05 μM/L. The initial concentration of the phosphate ions was 0.84 and decresed gradually during the phase of decomposition to its lowest value at 0.7 μM/L. The concentration of the nitrogen in the O. coarctata was initially between 1-1.5 mg DW, which increased to about 2 mg DW at the 7th day of the decomposition. The % DW nitrogen contents than decreased suddenly at 15th day reaching up to about 1 mg DW of the decomposed material. This

  13. Sequential diffusion of ammonium and nitrate from soil extracts to a polytetrafluoroethylene trap for 15N determination

    DEFF Research Database (Denmark)

    Sørensen, P.; Jensen, E.S.

    A novel diffusion method was used for preparation of NH4+- and NO3--N samples from soil extracts for N-15 determination. Ammonium, and nitrate following reduction to ammonia, are allowed to diffuse to an acid-wetted glass filter enclosed in polytetrafluoroethylene tape. The method was evaluated...... with simulated soil extracts obtained using 50 ml of 2 M potassium chloride solution containing 130-mu-g of NH4+-N (2.3 atom% N-15) and 120-mu-g of NO3--N (natural N-15 abundance). No cross-over in the N-15 abundances of NH4+-N and NO3--N was observed, indicating a quantitative diffusion process (72 h......, 25-degrees-C). Owing to the presence of inorganic nitrogen impurities in the potassium chloride, the N-15 enrichments should be corrected for the blank nitrogen content....

  14. Superconducting and mechanical properties of the bulk Bi(pb)SCCO system prepared via solid state and ammonium nitrate precipitation methods

    International Nuclear Information System (INIS)

    We have investigated the effect of preparation method on superconducting and mechanical properties of Bi(Pb)-2223 bulk samples using Bi1.85Pb0.35Sr2Ca2Cu3O10±y stoichiometry. Solid-state reaction and ammonium nitrate precipitation methods have been used for fabrication of the bulk samples. In addition, the effect of annealing time on BSCCO samples have been studied. Structural, electrical, magnetic and microhardness analyses of samples are performed by the X-ray powder diffraction (XRD), the Scanning Electron Microscopy (SEM), DC resistivity, AC susceptibility and Vickers microhardness test. The critical transition temperature, phase purity, surface morphology and crystallinity of the prepared bulk samples are compared with each other. Elasticity (E), brittleness (Bi), fracture toughness (KIC) and yield strength (Y) values are also determined according to annealing time, applied load and production parameters of materials

  15. Structural characterization of zinc(II) chloride in aqueous solution and in the protic ionic liquid ethyl ammonium nitrate by x-ray absorption spectroscopy

    Science.gov (United States)

    D'Angelo, Paola; Zitolo, Andrea; Ceccacci, Francesca; Caminiti, Ruggero; Aquilanti, Giuliana

    2011-10-01

    Extended x-ray absorption fine structure (EXAFS) spectroscopy has been used to investigate the species and structures existing in a series of ZnCl2-H2O-NaCl solutions with different chloride/zinc ratios and in a solution of ZnCl2 in the protic ionic liquid ethyl ammonium nitrate (EAN). The average coordination numbers and distances of zinc species were determined from the analysis of the EXAFS data. In aqueous solution the number of chloride ions tightly bounded to Zn2+ is significantly related to the chloride/zinc ratio, and no inner complex formation between Zn2+ and Cl- ions has been detected for low ZnCl2 concentration (0.1 and 0.2 M). Conversely, in the same concentration range (0.13 M) the ZnCl2 species do not dissociate in EAN and the Zn2+ first coordination shell has two chloride ions and is completed by two oxygen atoms of the nitrate anion. The results of this investigation show that notwithstanding the existence of similar characteristics between EAN and water, the solvation properties of the two solvents are markedly different.

  16. GROWTH AND COMPOSITION OF Arthrospira (Spirulina platensis IN A TUBULAR PHOTOBIOREACTOR USING AMMONIUM NITRATE AS THE NITROGEN SOURCE IN A FED-BATCH PROCESS

    Directory of Open Access Journals (Sweden)

    C. Cruz-Martínez

    2015-06-01

    Full Text Available AbstractNH4NO3 simultaneously provides a readily assimilable nitrogen source (ammonia and a reserve of nitrogen (nitrate, allowing for an increase in Arthrospira platensis biomass production while reducing the cost of the cultivation medium. In this study, a 22plus star central composite experimental design combined with response surface methodology was employed to analyze the influence of light intensity (I and the total amount of added NH4NO3 (Mt on a bench-scale tubular photobioreactor for fed-batch cultures. The maximum cell concentration (Xm, cell productivity (PX and biomass yield on nitrogen (YX/N were evaluated, as were the protein and lipid contents. Under optimized conditions (I = 148 μmol·photons·m-2·s-1 and Mt = 9.7 mM NH4NO3, Xm = 4710 ±34.4 mg·L-1, PX = 478.9 ±3.8 mg·L-1·d-1 and YX/N = 15.87 ±0.13 mg·mg-1 were obtained. The best conditions for protein content in the biomass (63.2% were not the same as those that maximized cell growth (I = 180 μmol·photons·m-2·s-1 and Mt = 22.5 mM NH4NO3. Based on these results, it is possible to conclude that ammonium nitrate is an interesting alternate nitrogen source for the cultivation of A. platensisin a fed-batch process and could be used for other photosynthetic microorganisms.

  17. Comparison of the uptake and assimilation of ammonium and nitrate in Indica and Japonica rice plants using the tracer 15N method

    International Nuclear Information System (INIS)

    The uptake of 15N-labeled ammonium and nitrate and their assimilation in 4-week-old Indica and Japonica rice plants were studied during 24 hr exposure to 2 mM solutions of (15NH4)2SO4 and/or Na15NO3. Although there was no clear difference in the uptake and assimilation of 15NH4+, significant differences in the uptake and assimilation of 15NO3- by both varieties were observed. When NH4+ or NO3- was supplied exclusively, the Indica rice plants absorbed the latter more effectively than the Japonica. In addition, despite a preference for uptake of NH4+ rather than NO3- as shown by both varieties when both forms were supplied together, the relative amounts of NO3- uptake by the Indica were higher than those of Japonica. On the other hand, the Indica rice plants reduced the absorbed 15NO3- more rapidly than the Japonica. The incorporation 15NO3- into the ethanol insoluble nitrogen fraction of the Indica rice also exceeded that of the Japonica. These results suggest that the Indica has the ability to utilize NO3- as a nitrogen source more effectively than the Japonica rice plants. (author)

  18. Superconducting and mechanical properties of the bulk Bi(pb)SCCO system prepared via solid state and ammonium nitrate precipitation methods

    Energy Technology Data Exchange (ETDEWEB)

    Safran, S., E-mail: safran@science.ankara.edu.tr [Ankara University, Faculty of Science, Department of Physics, Tandoğan, Ankara 06100 (Turkey); Center of Excellence for Superconductivity Research, 50 Year Campus, Golbaşı, Ankara (Turkey); Kılıçarslan, E.; Ozturk, H. [Ankara University, Faculty of Science, Department of Physics, Tandoğan, Ankara 06100 (Turkey); Center of Excellence for Superconductivity Research, 50 Year Campus, Golbaşı, Ankara (Turkey); Alp, M. [Center of Excellence for Superconductivity Research, 50 Year Campus, Golbaşı, Ankara (Turkey); Akdogan, M. [Center of Excellence for Superconductivity Research, 50 Year Campus, Golbaşı, Ankara (Turkey); Abant İzzet Baysal University, Department of Physics, Bolu (Turkey); Asikuzun, E.; Ozturk, O. [Kastamonu University, Department of Physics, Kastamonu (Turkey); Kastamonu University, Research and Application Center, Kastamonu (Turkey); Kılıç, A. [Ankara University, Faculty of Science, Department of Physics, Tandoğan, Ankara 06100 (Turkey); Center of Excellence for Superconductivity Research, 50 Year Campus, Golbaşı, Ankara (Turkey)

    2015-09-01

    We have investigated the effect of preparation method on superconducting and mechanical properties of Bi(Pb)-2223 bulk samples using Bi{sub 1.85}Pb{sub 0.35}Sr{sub 2}Ca{sub 2}Cu{sub 3}O{sub 10±y} stoichiometry. Solid-state reaction and ammonium nitrate precipitation methods have been used for fabrication of the bulk samples. In addition, the effect of annealing time on BSCCO samples have been studied. Structural, electrical, magnetic and microhardness analyses of samples are performed by the X-ray powder diffraction (XRD), the Scanning Electron Microscopy (SEM), DC resistivity, AC susceptibility and Vickers microhardness test. The critical transition temperature, phase purity, surface morphology and crystallinity of the prepared bulk samples are compared with each other. Elasticity (E), brittleness (B{sub i}), fracture toughness (K{sub IC}) and yield strength (Y) values are also determined according to annealing time, applied load and production parameters of materials.

  19. ROW METHOD OF SUGAR BEET (BETA VULGARIS L. FERTILIZATION WITH MULTICOMPONENT FERTILIZER BASED ON UREA-AMMONIUM NITRATE SOLUTION AS A WAY TO INCREASE NITROGEN EFFICIENCY

    Directory of Open Access Journals (Sweden)

    Przemysław BARŁÓG

    2010-12-01

    Full Text Available Sugar beet is the main crop commonly cultivated for sugar production in temperate regions of the World. Actual yields in main Central Europe producing countries are much lower, due to many limiting factors. Among them, nutrients supply is of great value, especially referring to efficiency of nitrogen, which is generally low. In the conducted study two methods of nitrogen application were compared (i broadcast of calcium saltpeter and (ii row application of the multicomponent fertilizer based on urea-ammonium-nitrate (UAN solution. The basic amount of the applied N was 75 kg ha-1. The highest yields of both taproots and refined sugar were harvested on the plot receiving 75 kg N-1 as UAN liquid multicomponent fertilizer and 50% of the recommended P and K rates. The positive effects of row application of liquid N fertilizer on taproot and sugar yields were also corroborated by high values of indices of agronomic efficiency for both N as well as P and K. However this method of sugar beets fertilization has some possibilities, as indicated by still high contents of melassogenic substances.

  20. Efficiency of ammonium nitrate phosphates of varying water-soluble phosphorous content for wheat and succeeding maize crop on different soil types

    International Nuclear Information System (INIS)

    Efficiency of 32P labelled ammonium nitrate phosphate (ANP) containding 30, 50 and 90 per cent of water-soluble phosphorus (WSP) vis-a-vis that of entirely water soluble monoammonium orthophosphate (MAP) for wheat and succeeding maize crop on deep black (vertisol), calcareous black (vertisol), alluvial-Tarai (mollisol) and grey brown alluvial (aridisol) soils was examined in greenhouse experiments. Data on wheat indicated that ANP (50 per cent WSP) was, in general, equally efficient to MAP and ANP (90 per cent WSP) in terms of drymatter yield and total uptake of phosphorus in all soils examined, however, the per cent utilization of applied fertilizer was significantly higher for MAP and ANP (90 per cent WSP) than those for ANP (50 per cent WSP) in all soils. In general, ANP (30 per cent WSP) was significantly inferior to MAP and ANP (90 per cent WSP) in all soils. Data on the succeeding maize crop grown to flowering indicated that residual value of ANP (30 per cent WSP) was equal to that of MAP and ANP (90 per cent WSP) in terms of drymatter yield and phosphorus uptake by the four soils examined. Complementary incubation studies conducted upto 60 days on the above four soils at field capacity moisture status indicated highest 0.5 M NaHCO3 (pH 8.5) extractable phosphorus levels in MAP treatments followed by ANP (50 per cent WSP) and least in ANP (30 per cent WSP) treatments. (author). 4 tables, 4 figures, 19 refs

  1. DETERMINACIÓN DE NITRATOS Y AMONIO EN MUESTRAS DE SUELO MEDIANTE EL USO DE ELECTRODOS SELECTIVOS NITRATE AND AMMONIUM DETERMINATION IN SOILS USING ION SELECTIVE ELECTRODES

    Directory of Open Access Journals (Sweden)

    Gloria Arango Pulgarín

    2005-06-01

    Full Text Available Con el objetivo de evaluar un método alternativo para la cuantificación de diferentes formas de nitrógeno, se determinó la concentración de nitratos (NO3- y amonio (NH4+ por dos métodos: Colorimetría y Electrodo de Ión Selectivo (EIS, en muestras de suelos cultivados con flores o banano en el departamento de Antioquia, Colombia. Se realizaron análisis de regresión y correlación para las concentraciones obtenidas por los dos métodos, que mostraron una asociación altamente significativa entre ellos. La determinación de NO3- mediante la formación de complejo coloreado con brucina ácida o mediante el uso de un electrodo selectivo para nitratos presentó un coeficiente de determinación altamente significativo (R² = 99,2. En forma similar, la determinación de NH4+ basada en la formación de complejo coloreado azul de indofenol ó utilizando el electrodo para amoniaco presentó un valor de R² = 98,4. El uso de electrodos presenta ventajas en comparación con las técnicas colorimétricas, que requieren mucho más tiempo y equipos mas costosos.In order to evaluate an alternative method for quantifying different forms of nitrogen, the concentrations of nitrates (NO3- and ammonium (NH4 were determined by two methods: Colorimetry and Ion Selective Electrode (ISE, in soil samples from soils cultivated with flowers or banana in the department of Antioquia,Colombia. Regression and correlation analyses on the concentrations obtained from the two methods showed highly significant relationships among them. The determination of NO3- by means of colored complexes with brucine acid or by means of the use of an electrode selective for nitrates exhibited a highly significant coefficient of determination (R² = 99.2. In a similar way, determination of NH4 based on the formation of blue colored complexes of indophenol or employing the electrode for ammoniac yielded a value of R² = 98.4. The use of electrodes has advantages over the colorimetric

  2. Experimental observations of detonation in ammonium-nitrate-fuel-oil (ANFO) surrounded by a high-sound speed, shockless, aluminum confiner

    Energy Technology Data Exchange (ETDEWEB)

    Jackson, Scott I [Los Alamos National Laboratory; Klyanda, Charles B [Los Alamos National Laboratory; Short, Mark [Los Alamos National Laboratory

    2010-01-01

    Detonations in explosive mixtures of ammonium-nitrate-fuel-oil (ANFO) confined by aluminum allow for transport of detonation energy ahead of the detonation front due to the aluminum sound speed exceeding the detonation velocity. The net effect of this energy transport on the detonation is unclear. It could enhance the detonation by precompressing the explosive near the wall. Alternatively, it could desensitize the explosive by crushing porosity required for shock initiation or destroying confinement ahead of the detonation. As these phenomena are not well understood, most numerical explosive models are unable to account for them. But with slowly detonating, non-ideal high explosive (NIHE) systems becoming increasing prevalent, proper understanding and prediction of the performance of these metal-confined NIHE systems is desirable. Experiments are discussed that measured the effect of this ANFO detonation energy transported upstream of the front by an aluminum confining tube. Detonation velocity, detonation front curvature, and aluminum response are recorded as a function of confiner wall thickness and length. Front curvature profiles display detonation acceleration near the confining surface, which is attributed to energy transported upstream modifying the flow. Average detonation velocities were seen to increase with increasing confiner thickness due to the additional inertial confinement of the reaction zone flow. Significant radial sidewall tube motion was observed immediately ahead of the detonation. Axial motion was also detected which interfered with the front curvature measurements in some cases. It was concluded that the confiner was able to transport energy ahead of the detonation and that this transport has a definite effect on the detonation.

  3. 冬小麦等4种作物对铵、硝态氮的吸收能力%Uptake capacity of ammonium and nitrate to several crops

    Institute of Scientific and Technical Information of China (English)

    田霄鸿; 李生秀; 王朝辉

    2000-01-01

    采用水培试验探讨了冬小麦、大豆、油菜和莴笋4种作物对硝、铵态氮的相对吸收能力以及这两种氮源对它们生长发育的影响。试验表明:(1)不同氮源对供试作物的生长发育影响极大。供给硝态氮,这些作物生长发育良好;供给等量的NO-3和NH+4(1∶1)时,蔬菜作物莴笋生长量下降幅度最大;供给铵态氨,莴笋和大豆极为敏感,在生长后期发生萎蔫。(2)供试作物在水培期间的总吸氮量与供给的氮源关系密切。供给NO-3时莴笋吸氮量显著高于供给等氮量NO-3和NH+4,莴笋、小麦供给等量NO-3+NH+4与单独供给NO-3时吸氮量大体相当;油菜、大豆供应等量NO-3和NH+4时吸氮量最大,供给NO-3时显著下降。除油菜外,其余3种作物供给NH+4时吸氮量均比其它氮源显著降低。(3)多数供试作物对NO-3和NH+4的吸收具有明显的偏向性。供给等量NO-3+NH+4时,油菜与冬小麦吸收的NO-3显著多于NH+4,表现出喜硝性,莴笋与此相反,表现出喜铵性,而大豆对两种形态氮素的吸收量相差不多,表现出兼性吸收的特点。但上述偏向性具有阶段特点,即喜硝的作物可能在某一阶段表现出喜铵性状。%The solution culture experiment was conducted in order to investigate the relatively uptake capacity of lettuce,rape,soybean and wheat to nitrate and ammonium,as well as the influence of 3 different nitrogen sources on growth and development of these four crops.The obtained results showed that:(1) When the distilled water was supplied as the growth medium in the nutrient solution,different nitrogen sources greatly affected on the growth and development of lettuce,rape,soybean and wheat.When nitrate was solely supplied,all of these crops growed very well;when the same amount of nitrate and ammonium was supplied as nitrogen source,to some extent the growth amount of lettuce decreased;While ammonium was solely supplied,the growth

  4. Nitrato de amônio e nitrato de potássio no desenvolvimento in vitro de embriões somáticos de pupunheiras Ammonium nitrate and potassium nitrate on in vitro peach palm somatic embryos development

    Directory of Open Access Journals (Sweden)

    Thaís Lobo dos Santos

    2010-07-01

    Full Text Available A pupunheira tem se mostrado boa alternativa à exploração extrativista de espécies como juçara e açaí. Porém, quando produzida via sementes apresenta plantio heterogêneo, o que torna a micropropagação ótima alternativa para seu cultivo em larga escala. O experimento objetivou avaliar a influência da interação entre nitrato de amônio e nitrato de potássio no enraizamento de microplantas obtidas a partir do desenvolvimento in vitro de embriões somáticos de pupunheiras, visando otimizar seu protocolo de micropropagação. Os embriões foram inoculados em meio MS com diferentes concentrações de NH4NO3 e KNO3. Aos 120 e 240 dias de cultivo, foram avaliados parâmetros morfofisiológicos do desenvolvimento radicular. Aos 120 dias, nas concentrações mais baixas de nitrogênio, houve estímulo ao crescimento das raízes e a maior ramificação radicular ocorreu com baixas concentrações de NH4NO3 e altas de KNO3. Aos 240 dias, notou-se redução do crescimento radicular e raízes finas prevalecentes. Conclui-se que até 120 dias as microplantas devem ser mantidas em meio com concentrações menores de NH4NO3 e maiores de KNO3 que as empregadas no meio MS, voltando para as concentrações usuais após esse período.Pejibaye is a good alternative for the extractive exploration of species such as juçara and açaí. However, when it is produced by seeds its planting is heterogeneous, which makes micropropagation a good alternative for cultivation in large scale. This study aimed to evaluate the influence of the interaction between ammonium nitrate and potassium nitrate on peach palm somatic embryos rooting in vitro cultivated, for optimization of the micropropagation protocol. The embryos were inoculated in MS medium with different concentrations of NH4NO3 and KNO3. Morphophisyologic parameters of root development were measured at 120 and 240 days of cultivation. At 120 days, at lower nitrogen concentrations, roots were stimulated

  5. Ammonium generation during SRAT cycle

    International Nuclear Information System (INIS)

    During the IDMS noble-metal demonstration runs ammonium nitrate deposition was found in the vessel vent system of the feed preparation area. In the bench-scale experiments of studying the hydrogen generation during the sludge treatment cycle, ammonium ion production was also monitored. It was found that: During a simulation of the DWPF Cold Chemical Runs SRAT cycle no detectable amount of ammonium ions was generated when treating a non-noble-metal containing sludge simulant according to the nitric acid flowsheet. Ammonium ions were generated during the SRAT-SME cycle when treating the noble-metal containing sludge with either formic acid or nitric acid/late-washing PHA. This is due to the reaction between formic acid and nitrate catalyzed by the noble metals in the sludge simulant. Ammonium ion production closely followed the hydrogen evolution from the catalytic decomposition of formic acid. This report summarizes the results of the production of ammonia during the SRAT cycle

  6. Nitrogênio na adubação química do cafeeiro: doses e parcelamentos do nitrocálcio Nitrogen fertilizer for coffee: rates and splitted applications of lime ammonium nitrate

    Directory of Open Access Journals (Sweden)

    Genésio da Silva Cervellini

    1986-01-01

    Full Text Available Nitrocálcio nas quantidades de 60, 120, 180 e 240 gramas de N por cafeeiro e por ano foi aplicado em parcelamentos diferentes, de acordo com os tratamentos e em três locais com início em 1973/74: Centro Experimental de Campinas, Estação Experimental de Mococa e Estação Experimental de Ribeirão Preto. Foram estudados os efeitos das quantidades crescentes e avaliadas as conveniências do parcelamento das doses de N aplicadas. Os acréscimos de produção com a elevação dessas doses foram bastante grandes até 120g, passando, a partir dessa quantidade, a aumentos menores. Os efeitos residuais do sulfato de amônio, Nitrocálcio, uréia e salitre-do-chile aplicados quatro anos antes do início do experimento ainda afetaram as produções, passados dez anos das últimas aplicações, reduzindo-as mais para as correspondentes ao salitre-do-chile e uréia. Os parcelamentos utilizados não favoreceram dados consistentes para conclusões, devendo seu estudo ter continuidade em novas séries de ensaios.Three experiments were carried out beginning in 1973/74 in a Red Latosol transition to Clay Red Yellow Latosol at the Centro Experimental of Campinas, in a Red-Yellow Podzolic Soil at Estação Experimental of Mococa, and on a Ortho Red Latosol at Estação Experimental of Ribeirão Preto, State of São Paulo, Brazil, in order to study nitrogen application on the coffee tree. Lime ammonium nitrate was applied at rates of 60, 120, 180, and 240g of N per plant in splitted applications as follows: in just one time by October and by December; in two times, by January and February; and in four times by October, December, January, and February. High yield increases were obtained with N applications rates up to 120g of N per plant. With higher rates further yield increments were about 5 or 10%. The residual effects of ammonium sulfate, lime ammonium nitrate, Chilean nitrate and urea were still present ten years after the last application. The data on

  7. Teores de nitrato (NO3- e amônio (NH4+ nas águas do aqüífero Barreiras nos bairros do Reduto, Nazaré e Umarizal - Belém/PA Nitrate (NO3- and ammonium (NH4+ contents in the Barreiras aquifer waters in the districts of Reduto, Nazaré and Umarizal - Belém, PA

    Directory of Open Access Journals (Sweden)

    Natalina Maria Tinôco Cabral

    2007-01-01

    Full Text Available This paper evaluates the occurrence of nitrate and ammonium in the Barreiras aquifer in the metropolitan area of Belém, Pará State, Brazil. The results show that some wells display ammonium and nitrate concentrations above or close to the limits of water potability regulations. The main cause of the pollution of these waters is related the local disposal of domestic effluents and/or leakage from pipes of old sewage systems.

  8. Effects of chromium and cobalt compounds on burning rate of ammonium nitrate/hydroxyl-terminated polybutadiene composite propellants. Shosan ammonium/HTPB kei composite suishin'yaku no nensho sokudo ni oyobosu chromium to cobalt kagobutsu no eikyo

    Energy Technology Data Exchange (ETDEWEB)

    Hagihara, Y.; Ichikawa, T.; Shinpo, H.; Suzuki, M. (The National Defense Academy, Yokosuka (Japan))

    1991-12-31

    Study was made on the effects of chromium and cobalt compounds on burning rate of AN/HTPB composite propellants by using 14 types of chromium and cobalt compounds as catalysts and it was clear that burning rate of composite propellants increases with all catalysts and increase in burning rate by ammonium dichromate and chromium (III) acetylacetone is significantly large. Pressure exponent for cobalt(II) oxide and cobalt(II) benzoate has decreased but it has increased with other catalysts. Pressure exponent has significantly increased in the case of cobalt 2-ethylhexanoate and cobalt(II) acetylacetone. Effect of compounds on slurry viscosity also has shown the decrease in the viscosity except chromium(III) oxide and cobalt(II,III) oxide, and in the case of cobalt 2-ethylhexanoate the viscosity is significantly low. Drophammer sensitivity of AN is not affected with the added compounds. 4 refs., 3 figs., 4 tabs.

  9. Nitrate and ammonium in soil solution in tobacco management systems Nitrato e amônio na solução do solo em sistemas de manejo para cultura do fumo

    Directory of Open Access Journals (Sweden)

    Douglas Rodrigo Kaiser

    2010-04-01

    Full Text Available Tobacco farmers of southern Brazil use high levels of fertilizers, without considering soil and environmental attributes, posing great risk to water resources degradation. The objective of this study was to monitor nitrate and ammonium concentrations in the soil solution of an Entisol in and below the root zone of tobacco under conventional tillage (CT, minimum tillage (MT and no-tillage (NT. The study was conducted in the small-watershed Arroio Lino, in Agudo, State of Rio Grande do Sul, Brazil. A base fertilization of 850 kg ha-1 of 10-18-24 and topdressing of 400 kg ha-1 of 14-0-14 NPK fertilizer were applied. The soil solution was sampled during the crop cycle with a tension lysimeter equipped with a porous ceramic cup. Ammonium and nitrate concentrations were analyzed by the distillation and titration method. Nitrate concentrations, ranging from 8 to 226 mg L-1, were highest after initial fertilization and decreased during the crop cycle. The average nitrate (N-NO3- concentration in the root zone was 75 in NT, 95 in MT, and 49 mg L-1 in CT. Below the root zone, the average nitrate concentration was 58 under NT, 108 under MT and 36 mg L-1 under CT. The nitrate and ammonium concentrations did not differ significantly in the management systems. However, the nitrate concentrations measured represent a contamination risk to groundwater of the watershed. The ammonium concentration (N-NH4+ decreased over time in all management systems, possibly as a result of the nitrification process and root uptake of part of the ammonium by the growing plants.Os fumicultores do sul do Brasil seguem pacotes tecnológicos que impõem o uso de altas doses de fertilizantes, sem considerar os atributos do solo e do ambiente, representando grande risco para a degradação dos recursos hídricos. O objetivo deste trabalho foi monitorar as concentrações de nitrato e de amônio na solução do solo da região do sistema radicular e abaixo deste, em Neossolo Lit

  10. Effect of urea: ammonium: nitrate ratios in nutrient solution on photosynthesis and quantitative properties of rose cut flower in soilless culture

    Directory of Open Access Journals (Sweden)

    M. Hosseini Farahi

    2013-07-01

    Full Text Available In order to investigate the effects of different forms of nitrogen in nutrient solution on photosynthesis rate and quantitative properties of rose cv. Dolcvita, an experiment was conducted in a randomized complete blocks design with seven ratios of urea: NH4+: NO3- (0-100-0, 0-50-50, 0-0-100, 50-0-50, 25-25-50, 15-15-70 and 0-0-100 and three replications, in a hydroponic greenhouse which grows rose flower. The rooted plants of rose cv. Dolcvita were potted filled with perlite and cocopeat (50:50 substrates. Then, quantitative properties such as plant stalk height, bud length, diameter of bud and stem, leaf area index, vase life, fresh weight of stalk, leaf greenness and photosynthesis parameters were measured. The results showed that increasing the ammonium in nutrient solution reduced the photosynthesis rate, water use efficiency and leaf mesophyll efficiency. The highest stalk height was obtained from 25-25-50 and 0-0-100 treatments (88.3 cm and 86.9 cm, respectively. The highest fresh weight of stalk was obtained in 0-0-100 treatment. Application of 50-0-50 treatment increased leaf greenness as compared to other treatments. When ammonium was increased in nutrition solution, the vase life was reduced. The highest and lowest vase lives were obtained from 25-25-50 and 100-0-0 treatments (17.6 and 11.1 days, respectively.

  11. Efeito da homeopatia Ammonium Carbonicum na minimização da lixiviação de nitrato Effect of the homeopathy Ammonium Carbonicum in the minimization of nitrate leaching

    Directory of Open Access Journals (Sweden)

    Carolina Cardoso Lisboa

    2007-04-01

    Full Text Available Avaliou-se o efeito da solução homeopática Ammonium Carbonicum em duas dinamizações, CH3 e CH30, sobre a lixiviação de NO-3. A hipótese inicial foi a de que essas soluções homeopáticas atuariam na microbiota do solo otimizando a utilização de N pela planta. Esse estudo foi conduzido em casa-de-vegetação e utilizaram-se amostras deformadas do horizonte A de um Latossolo Vermelho distroférrico típico muito argiloso, 00,15 m, localizado no campus da UFLA. As colunas de solo foram semeadas com milho (Zea mays L. e tinham 0,20 x 0,20 m. A irrigação e medição do volume lixiviado foi realizada diariamente. A aplicação dos tratamentos homeopáticos foi realizada via irrigação. As análises do lixiviado foram feitas duas vezes por semana. No lixiviado, mediram-se os teores de NO-3 e NH+4 Após 93 dias, as colunas foram seccionadas em camadas de 0,05 m e as amostras, analisadas quanto à fertilidade, incluindo NO-3, NH+4 e N total. O delineamento experimental foi inteiramente casualizado, com três repetições, num esquema duplo-cego com placebo. O efeito da solução homeopática na minimização da lixiviação deNO-3 não foi relevante nas condições deste estudo.The objective of this study was to evaluate the effect of the homeopathic solution Ammonium Carbonicum in two dynamizations CH3 and CH30 on NO-3 leaching. The early hypothesis was that those homeopathic solutions would act upon soil microbiota optimizing the use of N by the plant. This study was conducted in greenhouse and samples of the A horizon of a very clayey typic dystroferric Red Latosol, 00.15m, situated on the UFLA campus were utilized. The soil columns were sowed with corn (Zea mays L. and were 0.20 x 0.20 m. Irrigation and leached volume measurement was performed daily. The application of the homeopathic treatments was accomplished via irrigation. The analyses of the leachate were done twice a week. In the leachate, the contents of NO-3 and NH+4 were

  12. Fine-scale simulation of ammonium and nitrate over the South Coast Air Basin and San Joaquin Valley of California during CalNex-2010

    Science.gov (United States)

    Kelly, James T.; Baker, Kirk R.; Nowak, John B.; Murphy, Jennifer G.; Markovic, Milos Z.; VandenBoer, Trevor C.; Ellis, Raluca A.; Neuman, J. Andrew; Weber, Rodney J.; Roberts, James M.; Veres, Patrick R.; Gouw, Joost A.; Beaver, Melinda R.; Newman, Sally; Misenis, Chris

    2014-03-01

    National ambient air quality standards (NAAQS) have been set for PM2.5 due to its association with adverse health effects. PM2.5 design values in the South Coast Air Basin (SoCAB) and San Joaquin Valley of California exceed NAAQS levels, and NH4+ and NO3- make up the largest fraction of total PM2.5 mass on polluted days. Here we evaluate fine-scale simulations of PM2.5 NH4+ and NO3- with the Community Multiscale Air Quality model using measurements from routine networks and the California Research at the Nexus of Air Quality and Climate Change 2010 campaign. The model correctly simulates broad spatial patterns of NH4+ and NO3- including the elevated concentrations in eastern SoCAB. However, areas for model improvement have been identified. NH3 emissions from livestock and dairy facilities appear to be too low, while those related to waste disposal in western SoCAB may be too high. Analyses using measurements from flights over SoCAB suggest that problems with NH3 predictions can influence NO3- predictions there. Offline ISORROPIA II calculations suggest that overpredictions of NHx in Pasadena cause excessive partitioning of total nitrate to the particle phase overnight, while underpredictions of Na+ cause too much partitioning to the gas phase during the day. Also, the model seems to underestimate mixing during the evening boundary layer transition leading to excessive nitrate formation on some nights. Overall, the analyses demonstrate fine-scale variations in model performance within and across the air basins. Improvements in inventories and spatial allocations of NH3 emissions and in parameterizations of sea spray emissions, evening mixing processes, and heterogeneous ClNO2 chemistry could improve model performance.

  13. 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. PMID:23767347

  14. Study of the influence of radiolysis on the stability of plutonium III. Application to a heterogeneous medium formed by a nitric solution of ferrous ions and an organic solution of trilauryl-ammonium nitrate

    International Nuclear Information System (INIS)

    The objective of this research thesis is to study the behaviour of plutonium 238 in media which are commonly used to isolate it from other elements such as neptunium and fission products created during the neutron irradiation of the neptunium 237 isotope. As plutonium 238 purification processes are all based on redox reaction, it is essential to know the influence of radiolysis on the redox behaviour, and on the distribution coefficients of this isotope in solutions used during its separation from the neptunium 237 isotope. Therefore, it is necessary to study the influence of radiolysis on the stability of plutonium with an oxidation III level. As this extraction is performed by an organic solvent (trilauryl-ammonium nitrate), this study addresses the behaviour of plutonium in an emulsion formed by this solvent and the nitric aqueous solution previously adjusted in terms of Fe2+ ions. After a brief recall of bibliographical generalities related to radiolysis, the author presents and comments the Nernst law in the case of a two-phase system (emulsion), and reports the use of this law to obtain the plutonium potential-distribution coefficient relationship. The last part reports experimental data

  15. Sensitivity of nitrate aerosols to ammonia emissions and to nitrate chemistry: implications for present and future nitrate optical depth

    OpenAIRE

    F. Paulot; Ginoux, P.; Cooke, W. F.; L. J. Donner; S. Fan; Lin, M; J. Mao; Naik, V.; Horowitz, L.W.

    2015-01-01

    We update and evaluate the treatment of nitrate aerosols in the Geophysical Fluid Dynamics Laboratory (GFDL) atmospheric model (AM3). Accounting for the radiative effects of nitrate aerosols generally improves the simulated aerosol optical depth, although nitrate concentrations at the surface are biased high. This bias can be reduced by increasing the deposition of nitrate to account for the near-surface volatilization of ammonium nitrate or by neglecting th...

  16. Nitrogen assimilation and nitrate reductase activity in tomato seedlings. I. Comparative studies on the influence of the Ca:Mg ratio on nitrogen metabolism in relation to absorption of nitrates or ammonium salts

    Directory of Open Access Journals (Sweden)

    A. Suder-Moraw

    2015-05-01

    Full Text Available A change in the Ca:Mg ratio in the nutrient solution from the value optimal for tomato growth (3:1 to an unsuitable value (3:30 increases several times Mg2+ accumulation with simultaneous reduction of Ca2+ accumulation independently from the absorption of mineral nitrogen from, viz. NO3 - or NH4,- ions. Tomato seedlings receiving nitrogen in the form of NH4 show a complete tolerance to the unsuitable Ca:Mg ratio in the nutrient solution, whereas those supplied with NO3 react by growth inhibition, reduced dry weight increment and protein weight and inhibition of nitrogen reductase (NR activity. It is suggested that the reaction of plants to an excess of Mg2+ in the nutrient solution in relation to Ca2+ depends above all on the form in which nitrogen is supplied to the plants. It was found that the reduction of dry weight increment and protein synthesis preceded in time NR activity inhibition. Accumulation of excess Mg2+ and decreased Ca2+ accumulation occur rather rapidly. It is, therefore, supposed that the excess of accumulated Mg2+ induces a physiological deficit of Ca2+ in the tissue of plants taking up NO3 nitrogen. This calcium deficit leads to inhibtion of nitrate assimilation.

  17. Resposta do arroz irrigado ao suprimento de amônio e nitrato Rice growth as affected by combined ammonium and nitrate supply

    Directory of Open Access Journals (Sweden)

    Marquel Jonas Holzschuh

    2009-10-01

    supply for IRGA 417, but for cultivar Sasanishiki no differences were verified. It was concluded that NH4+ is toxic to rice plants, and is not the main available source of nitrogen. Nitrate is indispensable to increase the N uptake, normal plant growth and total cation absorption.

  18. Relación nitrato/amonio/urea y concentración de potasio en la producción de tomate hidropónico Relation nitrate / ammonium / urea and potassium concentration in hydroponic tomato production

    Directory of Open Access Journals (Sweden)

    Saúl Parra Terraza

    2012-02-01

    Full Text Available Plantas de tomate (Solanum lycopersicum L. cv. IB-9 fueron cultivadas en un sistema hidropónico con el objetivo de evaluar el efecto de la relación nitrato, amonio, urea (100/0/0, 85/15/0, 85/0/15y85/7.5/7.5 y la concentración de potasio (7 y 9 mol m-³ en el rendimiento de fruto y composición mineral de las plantas. El rendimiento de fruto no fue afectado por los tratamientos, por lo que se puede sustituir 15% del total de nitrógeno nítrico de la solución nutritiva con un porcentaje igual de nitrógeno amoniacal o ureico, o una mezcla de amonio y urea, cada una a 7.5%. El contenido de fósforo en las hojas aumentó significativamente con la interacción de 85/15/0 y 9 mol m-³ de potasio, mientras que la concentración de calcio en las hojas disminuyó estadísticamente con 100/0/0 y 9 mol m-³ de potasio.Tomato plants (Solanum lycopersicum L. cv. IB-9 were grown in ahydroponic system in orderto evaluate the effect of the ratio nitrate, ammonium, urea (100/0/0, 85/15/0, 85 / 0/15 and 85/7.5/7.5 and the concentration of potassium (7 and 9 mol m-³ in fruit yield and mineral composition of plants. The fruit yield was unaffected by the treatments, so that it can substitute 15% of the total nitrate nitrogen to the nutrient solution with an equal percentage of nitrogen or urea, or a mixture of ammonia and urea, each at 7.5 %. The phosphorus content in leaves was significantly increased by the interaction of 85/15/0 and 9 mol of potassium m-³, while the calcium concentration in leaves 100/0/0 statistically decreased and 9 mol m-³ potassium.

  19. A study on physicochemical properties of biochar and biochar-based ammonium nitrate fertilizers%生物质炭及炭基硝酸铵肥料理化性质研究

    Institute of Scientific and Technical Information of China (English)

    高海英; 陈心想; 张雯; 何绪生; 耿增超; 佘雕; 郭永利

    2012-01-01

    The physicochemical properties, morphology and water-retaining characteristics of two biochar and biochar-based ammonium nitrate fertilizers were investigated through ultimate and ash analysis, environmental scanning electronic microscope (ESEM), infrared microscopy (IR) and water characteristic curve in order to promote application of biochar to fertilizer. The results indicate that the carbon content of the two biochars tested in this research is more than 60% , and the biochars have small amount of N, H, O. The bamboo charcoal has much more ash than that of wood charcoal, and the ammonium nitrate (AN)-loaded content of them are about 8% and 18% respectively. The micro-structure of biochar-based AN fertilizer exhibits amorphous and porous structure, and keeps morphology characteristics of original biochcar basically. Chemical reaction doesn' t occur during the mixing of biochar with AN, and the AN-loaded to biochcar belongs to physical adsorption. The two biochars exhibit alkaline in pH, however, the pH of the AN - loaded biochar declines. The two biochars show some improvement for water-retaining capability of soils which depends on the application rate of biochar and soil texture. Bamboo charcoal and wood charcoal is also used as carrier for fertilizer nutrients.%通过元素分析、灰分测定、环境扫描电镜、红外光谱及土壤水分特征曲线测定,较系统分析和评价竹炭和木炭两种生物质炭及生物质炭基硝酸铵的部分理化性质、形貌结构及土壤水分吸持特征,以为生物质炭作肥料缓释载体应用提供参考.研究表明:实验所用生物质炭含碳量高达60%以上,并含有N、H、O等元素.竹炭比木炭富含灰分,而竹炭比木炭负载硝酸铵量低,其分别约为8%和18%.生物质炭基硝酸铵呈无定形、多孔状结构,基本保持生物质炭的微观形态.生物质炭与氮肥复合是靠物理吸附相结合的,复合中未发生化学变化.供试生物质炭呈碱性,

  20. 粉状铵油炸药现场混装车的设计与应用%Design and Application of Powdery Ammonium Nitrate Fuel Oil Explosive on Site Mixed Loading Truck

    Institute of Scientific and Technical Information of China (English)

    孙光; 熊代余; 龚兵; 孙大为; 臧怀壮; 李国仲

    2013-01-01

    For the sake of realization of on-site mixing powdery low detonation velocity ammonium nitrate fuel oil (ANFO)explosive used for explosion welding,a new type of powdery ANFO site-mixing truck was developed.It adopted rotating bin design,changed the original static discharge to dynamic discharge,and has solved the arching problem of tradi-tional ANFO mixing-loading truck material.The detonation velocity of the powder ANFO explosive is 1800-2500 m/s and the production speed is 200-300 kg/min,which meet the use requirement of explosion welding.The truck is able to pro-duce not only powdered but also porous granular ANFO explosives.%为实现爆炸焊接用低爆速粉状铵油炸药的现场混装,研制出一种新型粉状铵油炸药车。该车采用旋转料仓设计,将原有的静态出料改为动态出料,解决了传统铵油车存在的料仓起拱问题。所生产的粉状铵油炸药爆速1800~2500 m/s,生产速度200~300kg/min,满足了爆炸焊接用药的使用要求。该车不仅能够生产粉状铵油炸药,而且可以生产多孔粒状铵油炸药。

  1. 76 FR 70366 - Ammonium Nitrate Security Program

    Science.gov (United States)

    2011-11-14

    ... Department previously announced a series of public meetings on the same topic on October 2, 2011 (see 76 FR... public comment on August 3, 2011. See 73 FR 64280 (advance notice of proposed rulemaking); 76 FR 46908..., November 17, 2011, 10 a.m.-2 p.m., Hilton St. Petersburg Carillon Park, 950 Lake Carillon Drive,...

  2. Concurrence of Anaerobic Ammonium Oxidation and Organotrophic Denitrification in Presence of p-Cresol.

    Science.gov (United States)

    González-Blanco, G; Cervantes, F J; Beristain-Cardoso, R; Gómez, J

    2015-08-01

    This study was carried out to evaluate the capacity of anaerobic granular sludge for oxidizing ammonium and p-cresol with nitrate as terminal electron acceptor. Kinetics for the anaerobic oxidation of ammonium and p-cresol is described in this paper. The phenolic compound was very efficiently consumed, achieving 65 % of mineralization. Ammonium and nitrate were also consumed at 83 and 92 %, respectively, being the main product N2. Anaerobic ammonium oxidation was promoted owing to accumulation of nitrite, and it allowed the synergy of anaerobic ammonium oxidation and organotrophic denitrification for the simultaneous removal of ammonium, nitrate, and p-cresol. A carbonaceous intermediate partially identified was transiently accumulated, and it transitorily truncated the respiratory process of denitrification. These experimental results might be considered for defining strategies in order to remove nitrate, ammonium, and phenolic compounds from wastewaters. PMID:26062920

  3. Um método de investigação da assimilação heterotrófica do amônio e nitrato por organismos planctônicos A method for investigating the heterotrophic assimilation of ammonium and nitrate through planktonic organisms

    Directory of Open Access Journals (Sweden)

    Irineu Bianchini-Júnior

    2000-05-01

    ammonium and nitrate is investigated for various predetermined concentrations of water samples extracted from the upper subsurface of the littoral zone of a small reservoir (Lake IAG in São Paulo, Brazil ( 23º39’ S and 46º37’ W. Five concentrations were predetermined for added ammonium: 300; 370; 440; 650; 1280 µg.N.L-1 and nitrate: 340; 590; 890; 1090; 1590 µg.N.L-1. The samples were maintained under dark and oxygenated at a controlled temperature of 20ºC ± 1ºC, for the period of 9 days for ammonium and 11 days for nitrate. Once a day the concentrations of ammonium and nitrate in the flasks were analyzed colorimetric method. The highest uptake rate occurred at the initial concentrations of 300 µg.N.L-1 (k = 0,23 day-1 and 340 µg.N.L-1 (k = 0,25 day-1 for ammonium and nitrate respectively. These results indicate that the latter concentrations are close to the ideal conditions for assimilation of ammonium and nitrate by the microorganisms in the system. It is suggested therefore that these are the concentrations at which incubation processes should be started. In addition, concentrations above 500 µg.N.L-1 for ammonium and 600 µg.N.L-1 for nitrate are likely to cause inhibition of the assimilation process. The data do not follow a simple Michaelis-Menten equation, probably because some inhibition in the assimilation occurred.

  4. 减量控释氮肥对大棚甜椒产量及土壤硝态氮、铵态氮分布的影响%Effect of Reduced Controlled Release Nitrogen Fertilizer on the Sweet Pepper Yield and Distribution of Soil Nitrate,Ammonium Nitrogen

    Institute of Scientific and Technical Information of China (English)

    彭强; 李絮花; 王克安; 吕晓慧; 杨宁; 刘旭凤

    2012-01-01

    采用田间试验方法研究不同控释氮肥施用量对大棚甜椒生长及硝态氮、铵态氮含量分布的影响。结果表明,控释氮肥处理对大棚甜椒的产量、肥料利用率、氮肥农学效率、氮肥偏生产力较常规施肥有不同程度的提高,以RF30处理最佳。各施肥处理均显著增加了土壤全氮、甜椒Vc、可溶性糖、硝酸盐的含量,降低了可滴定酸的含量。施肥处理显著增加了0-60cm土层硝态氮含量,满足了甜椒在不同时期对氮素的需求。控释氮肥处理0-60cm土层铵态氮含量差异不大,常规施肥铵态氮含量明显下降。综合考虑在农民习惯性施肥基础上施用70%控释氮肥可以保证较高的产量和较好的果实品质。%Field experiment was carried out on the growth of greenhouse sweet pepper and distribution of ammonium,nitrate nitrogen content in different controlled-release nitrogen fertilizer.The results showed that in controlled-release nitrogen fertilizer treatment,the greenhouse sweet pepper yield,fertilizer utilization efficiency,nitrogen agronomic efficiency and nitrogen partial productivity were higher than the conventional fertilization increased to different extent,and the best treatment was RF30.The fertilizer treatment significantly increased the total nitrogen,pepper Vc,soluble sugar,and nitrate content,decreased titratable acid content.The fertilization treatments significantly increased the content of nitrate nitrogen in soil layer 0-60 cm,meeting the nitrogen demand in the different stages of the sweet pepper.With controlled release nitrogen fertilizer treatments,ammonium nitrogen content in soil layer 0-60 cm were not significant,but with conventional fertilizer treatments,ammonium nitrogen concentration decreased significantly.Considering farmer habitual fertilization,70% controlled-release nitrogen fertilizer can ensure higher yield and better quality of sweet pepper.

  5. Catalyzed reduction of nitrate in aqueous solutions

    International Nuclear Information System (INIS)

    Sodium nitrate and other nitrate salts in wastes is a major source of difficulty for permanent disposal. Reduction of nitrate using aluminum metal has been demonstrated, but NH3, hydrazine, or organic compounds containing oxygen would be advantageous for reduction of nitrate in sodium nitrate solutions. Objective of this seed money study was to determine minimum conditions for reduction. Proposed procedure was batchwise heating of aqueous solutions in closed vessels with monitoring of temperatures and pressures. A simple, convenient apparatus and procedure were demonstrated for observing formation of gaseous products and collecting samples for analyses. The test conditions were 250 degree C and 1000 psi max. Any useful reduction of sodium nitrate to sodium hydroxide as the primary product was not found. The nitrate present at pHs 3 or NH4NO3 is easily decomposed, and the effect of nitromethane at these low pHs was confirmed. When acetic acid or formic acid was added, 21 to 56% of the nitrate in sodium nitrate solutions was reduced by methanol or formaldehyde. With hydrazine and acetic acid, 73 % of the nitrate was decomposed to convert NaNO3 to sodium acetate. With hydrazine and formic acid, 36% of the nitrate was decomposed. If these products are more acceptable for final disposal than sodium nitrate, the reagents are cheap and the conversion conditions would be practical for easy use. Ammonium acetate or formate salts did not significantly reduce nitrate in sodium nitrate solutions

  6. Review: Mechanisms of ammonium toxicity and the quest for tolerance.

    Science.gov (United States)

    Esteban, Raquel; Ariz, Idoia; Cruz, Cristina; Moran, Jose Fernando

    2016-07-01

    Ammonium sensitivity of plants is a worldwide problem, constraining crop production. Prolonged application of ammonium as the sole nitrogen source may result in physiological and morphological disorders that lead to decreased plant growth and toxicity. The main causes of ammonium toxicity/tolerance described until now include high ammonium assimilation by plants and/or low sensitivity to external pH acidification. The various ammonium transport-related components, especially the non-electrogenic influx of NH3 (related to the depletion of (15)N) and the electrogenic influx of NH4(+), may contribute to ammonium accumulation, and therefore to NH3 toxicity. However, this accumulation may be influenced by increasing K(+) concentration in the root medium. Recently, new insights have been provided by "omics" studies, leading to a suggested involvement of GDP mannose-pyrophosphorylase in the response pathways of NH4(+) stress. In this review, we highlight the cross-talk signaling between nitrate, auxins and NO, and the importance of the connection of the plants' urea cycle to metabolism of polyamines. Overall, the tolerance and amelioration of ammonium toxicity are outlined to improve the yield of ammonium-grown plants. This review identifies future directions of research, focusing on the putative importance of aquaporins in ammonium influx, and on genes involved in ammonium sensitivity and tolerance. PMID:27181951

  7. New synthetic method and properties of ammonium dinitramide; Ammonium dinitramide no shingoseiho to sono butsuri kagakuteki tokusei

    Energy Technology Data Exchange (ETDEWEB)

    Hatano, H.; Onda, T.; Shiino, K. [Hosoya Kako Co. Ltd., Tokyo (Japan). Technology and Development Center; Miyazaki, S.; Matsuura, S. [Nissan Motor Co. Ltd., Saitama (Japan). Research and Development center

    1996-08-31

    Though, ammonium nitrate (AN) has been thought as solid propellant oxidizer, at present, ammonium perchlorate (AP) is mainly used because of the existence of crystal transition point, the improvement of propellant performance on AN and so forth. Ammonium dinitramide (ADN) can be used as an excellent oxidizer for high performance solid propellants, because it has much available oxygen. Furthermore, this propellant is smokeless, since ADN has no halogen resulting in generation of smoke on burning. ADN can be obtained by a new synthetic method which uses urea as starting substance and acquires nitrourea as intermediate product. According to this method, the yield is about 15% based on the amount of nitrourea. The hygroscopicity of this ADN is slightly higher than that of ammonium nitrate. Therefore, it is recommended to handle this substance at 50% of relative humidity or below. 13 refs., 7 figs., 4 tabs.

  8. Subsurface ammonium maxima in northern Bay of Bengal

    Digital Repository Service at National Institute of Oceanography (India)

    Satyanarayana, D.; Sahu, S.D.; Panigrahy, P.K.; Sarma, V.V.; Suguna, C.

    Environmental Research 31 (1991) 123-136 Subsurface Ammonium Maxima in Northern Bay of Bengal D. Satyanarayana, S. D. Sahu, P. K. Panigrahy School of Chemistry, Andhra University, Visakhapatnam 530 003, India V. V. Sarma & C. Suguna National Institute.... Inorganic phosphate was determined by the method of Murphy & Riley (1962), nitrite by the method of Bendschneider & Robinson (1952) and nitrate by the method of Morris & Riley (1963) as modified by Grasshoff (1964). Ammonium was determined by indophenol...

  9. Ammonium and nitrate in soil and upland rice yield as affected by cover crops and their desiccation time Amônio e nitrato no solo e produtividade do arroz de terras altas influenciados por plantas de cobertura e suas épocas de dessecação

    Directory of Open Access Journals (Sweden)

    Adriano Stephan Nascente

    2012-12-01

    Full Text Available The objective of this work was to evaluate the effect of cover crops and their desiccation times on upland rice yield and on the levels of nitrate and ammonium in a no-tillage soil. The experiment was carried out in a randomized blocks, with split plots and three replicates. Cover crops (plots were sowed in the off-season (March 2009. In November 2009, at 30, 20, 10 and 0 days before rice sowing (split plots, herbicide was applied on the cover crops (fallow, Panicum maximum, Urochloa ruziziensis, U. brizantha and millet. Straw and soil were sampled (0 - 10 cm at the sowing day, and after 7, 14, 21, 28 and 35 days. Straws from millet and fallow were degraded more rapidly and provided the lowest level of nitrate in the soil. Urochloa ruziziensis, U. brizantha and P. maximum produced higher amounts of dry matter, and provided the highest levels of nitrate in the soil. Millet provides the lowest nitrate/ammonium ratio and the highest upland rice yield. Desiccations carried out at 30 and 20 days before sowing had the largest levels of nitrate in the soil at the sowing date. Nitrogen content and forms in the soil are affected by cover crops and their desiccation times.O objetivo deste trabalho foi avaliar o efeito de plantas de cobertura e de suas épocas de dessecação na produtividade do arroz de terras altas e nos níveis de nitrato e amônio de solo em plantio direto. O experimento foi realizado em blocos ao acaso, com parcelas subdivididas e três repetições. As plantas de cobertura (parcelas foram semeadas na entressafra (março de 2009. Em novembro de 2009, aos 30, 20, 10 e 0 dias antes da semeadura do arroz (parcelas subdivididas, realizou-se o manejo químico das plantas de cobertura (pousio, Panicum maximum, Urochloa ruziziensis, U. brizantha e milheto. As palhadas e o solo (camada 0 - 10 cm foram amostrados no dia da semeadura do arroz e após 7, 14, 21, 28 e 35 dias. As palhas do milheto e do pousio degradaram-se mais rapidamente e

  10. Solvent extraction of rare earth (3) nitrates by trialkylmethylammonium nitrate from multicomponent solutions

    International Nuclear Information System (INIS)

    The extraction of rare earth (3) [praseodymium-lutetium, yttrium (3)] nitrates 0.4-1.10 mol/dm3 by solution of trialkyl-methylammonium in kerosene was studied. It is found that di- and trisolvates of rare earth (3) nitrates is formed in organic phase, extraction constants are determined. Physicochemical and mathematical models descriptive of distribution of metal (3) nitrates in binary and multicomponent systems are given. Optimum field of concentrations of rare earth mixture in rare earths was established during use of solutions of trialkylmethyl-ammonium nitrate in diluent

  11. Nitrate reductase activity in cabbage (Brassica oleracae var. capitata seedlings affected by the different nitrogen fertilizer forms

    Directory of Open Access Journals (Sweden)

    Metin Turan

    2013-12-01

    Full Text Available The effect of different nitrogen fertilizer (potassium nitrate, ammonium nitrate, ammonium sulphate, urea and farmyard manure on nitrate reductase activity in cabbage (Brassica oleracea var. capitata seedlings were studied. pH of the plant growth niedia was higher in the nitrate fertilizer treatment than the ammonium and other fertilizer forms. NO3--N application increased NRA in plant, but NH4+-N decreased NRA in plant. Harvesting date and different fertilizer doses increased NRA while NH4+-N decreased plant nitrate uptake. There was a significant relationship between NRA and fertilizer types.

  12. Nitrate ammonification in mangrove soils: a hidden source of nitrite?

    KAUST Repository

    Balk, Melike

    2015-03-02

    Nitrate reduction is considered to be a minor microbial pathway in the oxidation of mangrove-derived organic matter due to a limited supply of nitrate in mangrove soils. At a limited availability of this electron acceptor compared to the supply of degradable carbon, nitrate ammonification is thought to be the preferential pathway of nitrate reduction. Mangrove forest mutually differ in their productivity, which may lead to different available carbon to nitrate ratios in their soil. Hence, nitrate ammonification is expected to be of more importance in high- compared to low-productive forests. The hypothesis was tested in flow-through reactors that contain undisturbed mangrove soils from high-productive Avicennia germinans and Rhizophora mangle forests in Florida and low-productive Avicennia marina forests in Saudi Arabia. Nitrate was undetectable in the soils from both regions. It was assumed that a legacy of nitrate ammonification would be reflected by a higher ammonium production from these soils upon the addition of nitrate. Unexpectedly, the soils from the low-productive forests in Saudi Arabia produced considerably more ammonium than the soils from the high-productive forests in Florida. Hence, other environmental factors than productivity must govern the selection of nitrate ammonification or denitrification. A rather intriguing observation was the 1:1 production of nitrite and ammonium during the consumption of nitrate, more or less independent from sampling region, location, sampling depth, mangrove species and from the absence or presence of additional degradable carbon. This 1:1 ratio points to a coupled production of ammonium and nitrite by one group of nitrate-reducing microorganisms. Such a production of nitrite will be hidden by the presence of active nitrite-reducing microorganisms under the nitrate-limited conditions of most mangrove forest soils.

  13. Nitrate ammonification in mangrove soils: a hidden source of nitrite?

    Science.gov (United States)

    Balk, Melike; Laverman, Anniet M; Keuskamp, Joost A; Laanbroek, Hendrikus J

    2015-01-01

    Nitrate reduction is considered to be a minor microbial pathway in the oxidation of mangrove-derived organic matter due to a limited supply of nitrate in mangrove soils. At a limited availability of this electron acceptor compared to the supply of degradable carbon, nitrate ammonification is thought to be the preferential pathway of nitrate reduction. Mangrove forest mutually differ in their productivity, which may lead to different available carbon to nitrate ratios in their soil. Hence, nitrate ammonification is expected to be of more importance in high- compared to low-productive forests. The hypothesis was tested in flow-through reactors that contain undisturbed mangrove soils from high-productive Avicennia germinans and Rhizophora mangle forests in Florida and low-productive Avicennia marina forests in Saudi Arabia. Nitrate was undetectable in the soils from both regions. It was assumed that a legacy of nitrate ammonification would be reflected by a higher ammonium production from these soils upon the addition of nitrate. Unexpectedly, the soils from the low-productive forests in Saudi Arabia produced considerably more ammonium than the soils from the high-productive forests in Florida. Hence, other environmental factors than productivity must govern the selection of nitrate ammonification or denitrification. A rather intriguing observation was the 1:1 production of nitrite and ammonium during the consumption of nitrate, more or less independent from sampling region, location, sampling depth, mangrove species and from the absence or presence of additional degradable carbon. This 1:1 ratio points to a coupled production of ammonium and nitrite by one group of nitrate-reducing microorganisms. Such a production of nitrite will be hidden by the presence of active nitrite-reducing microorganisms under the nitrate-limited conditions of most mangrove forest soils. PMID:25784903

  14. Nitrate ammonification in mangrove soils: A hidden source of nitrite?

    Directory of Open Access Journals (Sweden)

    Melike eBalk

    2015-03-01

    Full Text Available Nitrate reduction is considered to be a minor microbial pathway in the oxidation of mangrove-derived organic matter due to a limited supply of nitrate in mangrove soils. At a limited availability of this electron acceptor compared to the supply of degradable carbon, nitrate ammonification is thought to be the preferential pathway of nitrate reduction. Mangrove forest mutually differ in their productivity, which may lead to different available carbon to nitrate ratios in their soil. Hence, nitrate ammonification is expected to be of more importance in high- compared to low-productive forests.The hypothesis was tested in flow-through reactors that contain undisturbed mangrove soils from high-productive Avicennia germinans and Rhizophora mangle forests in Florida and low-productive Avicennia marina forests in Saudi Arabia. Nitrate was undetectable in the soils from both regions. It was assumed that a legacy of nitrate ammonification would be reflected by a higher ammonium production from these soils upon the addition of nitrate. Unexpectedly, the soils from the low-productive forests in Saudi Arabia produced considerably more ammonium than the soils from the high-productive forests in Florida. Hence, other environmental factors than productivity must govern the selection of nitrate ammonification or denitrification. A rather intriguing observation was the 1:1 production of nitrite and ammonium during the consumption of nitrate, more or less independent from sampling region, location, sampling depth, mangrove species and from the absence or presence of additional degradable carbon. This 1:1 ratio points to a coupled production of ammonium and nitrite by one group of nitrate-reducing microorganisms. Such a production of nitrite will be hidden under the nitrate-limited conditions of most mangrove forest soils.

  15. Elevated ammonium levels

    DEFF Research Database (Denmark)

    Søgaard, Rikke; Novak, Ivana; MacAulay, Nanna

    2012-01-01

    Increased ammonium (NH(4)(+)/NH(3)) in the brain is a significant factor in the pathophysiology of hepatic encephalopathy, which involves altered glutamatergic neurotransmission. In glial cell cultures and brain slices, glutamate uptake either decreases or increases following acute ammonium expos...

  16. Sensitivity of nitrate aerosols to ammonia emissions and to nitrate chemistry: implications for present and future nitrate optical depth

    Directory of Open Access Journals (Sweden)

    F. Paulot

    2015-09-01

    Full Text Available We update and evaluate the treatment of nitrate aerosols in the Geophysical Fluid Dynamics Laboratory (GFDL atmospheric model (AM3. Accounting for the radiative effects of nitrate aerosols generally improves the simulated aerosol optical depth, although nitrate concentrations at the surface are biased high. This bias can be reduced by increasing the deposition of nitrate to account for the near-surface volatilization of ammonium nitrate or by neglecting the heterogeneous production of nitric acid to account for the inhibition of N2O5 reactive uptake at high nitrate concentrations. Globally, uncertainties in these processes can impact the simulated nitrate optical depth by up to 25 %, much more than the impact of uncertainties in the seasonality of ammonia emissions (6 % or in the uptake of nitric acid on dust (13 %. Our best estimate for present-day fine nitrate optical depth at 550 nm is 0.006 (0.005–0.008. We only find a modest increase of nitrate optical depth (2 (−40 % and ammonia (+38 % from 2010 to 2050. Nitrate burden is projected to increase in the tropics and in the free troposphere, but to decrease at the surface in the midlatitudes because of lower nitric acid concentrations. Our results suggest that better constraints on the heterogeneous chemistry of nitric acid on dust, on tropical ammonia emissions, and on the transport of ammonia to the free troposphere are needed to improve projections of aerosol optical depth.

  17. Influence of Ammonium Salts and Cane Molasses on Growth of Alcaligenes eutrophus and Production of Polyhydroxybutyrate

    OpenAIRE

    Beaulieu, M.; Beaulieu, Y.; Melinard, J.; Pandian, S.; GOULET, J.

    1995-01-01

    The production of polyhydroxybutyrate (PHB) by Alcaligenes eutrophus DSM 545 was studied in a synthetic medium with 3% glucose at pH 7.0 supplemented with several ammonium substrates and cane molasses. Growth was measured by dry cell weight, and the PHB content was measured by gas chromatography. The effects of ammonium sources such as sulfate, nitrate, phosphate, and chloride salts and those of different ammonium sulfate concentrations were evaluated. The best growth and PHB production were ...

  18. Sensitivity of nitrate aerosols to ammonia emissions and to nitrate chemistry: implications for present and future nitrate optical depth

    Science.gov (United States)

    Paulot, F.; Ginoux, P.; Cooke, W. F.; Donner, L. J.; Fan, S.; Lin, M.-Y.; Mao, J.; Naik, V.; Horowitz, L. W.

    2016-02-01

    We update and evaluate the treatment of nitrate aerosols in the Geophysical Fluid Dynamics Laboratory (GFDL) atmospheric model (AM3). Accounting for the radiative effects of nitrate aerosols generally improves the simulated aerosol optical depth, although nitrate concentrations at the surface are biased high. This bias can be reduced by increasing the deposition of nitrate to account for the near-surface volatilization of ammonium nitrate or by neglecting the heterogeneous production of nitric acid to account for the inhibition of N2O5 reactive uptake at high nitrate concentrations. Globally, uncertainties in these processes can impact the simulated nitrate optical depth by up to 25 %, much more than the impact of uncertainties in the seasonality of ammonia emissions (6 %) or in the uptake of nitric acid on dust (13 %). Our best estimate for fine nitrate optical depth at 550 nm in 2010 is 0.006 (0.005-0.008). In wintertime, nitrate aerosols are simulated to account for over 30 % of the aerosol optical depth over western Europe and North America. Simulated nitrate optical depth increases by less than 30 % (0.0061-0.010) in response to projected changes in anthropogenic emissions from 2010 to 2050 (e.g., -40 % for SO2 and +38 % for ammonia). This increase is primarily driven by greater concentrations of nitrate in the free troposphere, while surface nitrate concentrations decrease in the midlatitudes following lower concentrations of nitric acid. With the projected increase of ammonia emissions, we show that better constraints on the vertical distribution of ammonia (e.g., convective transport and biomass burning injection) and on the sources and sinks of nitric acid (e.g., heterogeneous reaction on dust) are needed to improve estimates of future nitrate optical depth.

  19. Transport and fate of ammonium and its impact on uranium and other trace elements at a former uranium mill tailing site

    International Nuclear Information System (INIS)

    Highlights: • Nitrification of ammonium evidenced by stable isotopes of nitrate at a mining site. • Concentrations of uranium and other trace elements related to ammonium conc. • Observed impact of ammonium on redox, pH, and possibly complexation. • Proposed impact of transformation of NO3 and NH4 on trace elements. - Abstract: The remediation of ammonium-containing groundwater discharged from uranium mill tailing sites is a difficult problem facing the mining industry. The Monument Valley site is a former uranium mining site in the southwest US with both ammonium and nitrate contamination of groundwater. In this study, samples collected from 14 selected wells were analyzed for major cations and anions, trace elements, and isotopic composition of ammonium and nitrate. In addition, geochemical data from the U.S. Department of Energy (DOE) database were analyzed. Results showing oxic redox conditions and correspondence of isotopic compositions of ammonium and nitrate confirmed the natural attenuation of ammonium via nitrification. Moreover, it was observed that ammonium concentration within the plume area is closely related to concentrations of uranium and a series of other trace elements including chromium, selenium, vanadium, iron, and manganese. It is hypothesized that ammonium–nitrate transformation processes influence the disposition of the trace elements through mediation of redox potential, pH, and possibly aqueous complexation and solid-phase sorption. Despite the generally relatively low concentrations of trace elements present in groundwater, their transport and fate may be influenced by remediation of ammonium or nitrate at the site

  20. Nitrate reduction functional genes and nitrate reduction potentials persist in deeper estuarine sediments. Why?

    Directory of Open Access Journals (Sweden)

    Sokratis Papaspyrou

    Full Text Available Denitrification and dissimilatory nitrate reduction to ammonium (DNRA are processes occurring simultaneously under oxygen-limited or anaerobic conditions, where both compete for nitrate and organic carbon. Despite their ecological importance, there has been little investigation of how denitrification and DNRA potentials and related functional genes vary vertically with sediment depth. Nitrate reduction potentials measured in sediment depth profiles along the Colne estuary were in the upper range of nitrate reduction rates reported from other sediments and showed the existence of strong decreasing trends both with increasing depth and along the estuary. Denitrification potential decreased along the estuary, decreasing more rapidly with depth towards the estuary mouth. In contrast, DNRA potential increased along the estuary. Significant decreases in copy numbers of 16S rRNA and nitrate reducing genes were observed along the estuary and from surface to deeper sediments. Both metabolic potentials and functional genes persisted at sediment depths where porewater nitrate was absent. Transport of nitrate by bioturbation, based on macrofauna distributions, could only account for the upper 10 cm depth of sediment. A several fold higher combined freeze-lysable KCl-extractable nitrate pool compared to porewater nitrate was detected. We hypothesised that his could be attributed to intracellular nitrate pools from nitrate accumulating microorganisms like Thioploca or Beggiatoa. However, pyrosequencing analysis did not detect any such organisms, leaving other bacteria, microbenthic algae, or foraminiferans which have also been shown to accumulate nitrate, as possible candidates. The importance and bioavailability of a KCl-extractable nitrate sediment pool remains to be tested. The significant variation in the vertical pattern and abundance of the various nitrate reducing genes phylotypes reasonably suggests differences in their activity throughout the

  1. Assessment of the synthesis routes conditions for obtaining ammonium dinitramide by the FT-IR

    OpenAIRE

    José Irineu Sampaio de Oliveira; Márcio Yuji Nagamachi; Milton Faria Diniz; Elizabeth da Costa Mattos; Rita de Cássia Lazzarini Dutra

    2011-01-01

    Over the last two decades, many routes have been proposed to synthesize ammonium dinitramide (ADN). However, most of them lie in routes in which reactants are too expensive for large-scale production. In this sense, the use of ordinary reactants is of paramount importance in this case. The aim in this synthesis consists on nitrating a starting reactant in a reaction known as nitration. Both the nitrating agent and the starting reactant should preferably be ordinary, narrowing the possibility ...

  2. Root ABA Accumulation Enhances Rice Seedling Drought Tolerance under Ammonium Supply: Interaction with Aquaporins

    Science.gov (United States)

    Ding, Lei; Li, Yingrui; Wang, Ying; Gao, Limin; Wang, Min; Chaumont, François; Shen, Qirong; Guo, Shiwei

    2016-01-01

    In previous studies, we demonstrated that ammonium nutrition enhances the drought tolerance of rice seedlings compared to nitrate nutrition and contributes to a higher root water uptake ability. It remains unclear why rice seedlings maintain a higher water uptake ability when supplied with ammonium under drought stress. Here, we focused on the effects of nitrogen form and drought stress on root abscisic acid (ABA) concentration and aquaporin expression using hydroponics experiments and stimulating drought stress with 10% PEG6000. Drought stress decreased the leaf photosynthetic rate and stomatal conductivity and increased the leaf temperature of plants supplied with either ammonium or nitrate, but especially under nitrate supply. After 4 h of PEG treatment, the root protoplast water permeability and the expression of root PIP and TIP genes decreased in plants supplied with ammonium or nitrate. After 24 h of PEG treatment, the root hydraulic conductivity, the protoplast water permeability, and the expression of some aquaporin genes increased in plants supplied with ammonium compared to those under non-PEG treatment. Root ABA accumulation was induced by 24 h of PEG treatment, especially in plants supplied with ammonium. The addition of exogenous ABA decreased the expression of PIP and TIP genes under non-PEG treatment but increased the expression of some of them under PEG treatment. We concluded that drought stress induced a down-regulation of aquaporin expression, which appeared earlier than did root ABA accumulation. With continued drought stress, aquaporin expression and activity increased due to root ABA accumulation in plants supplied with ammonium.

  3. Índice de uniformidade de distribuição do amônio, nitrato, potássio e fósforo, em Latossolos sob condições de fertigação Uniformity distribution index of ammonium, nitrate, potassium and phosphorus in fertigated Oxisols

    Directory of Open Access Journals (Sweden)

    Guilherme K. Donagemma

    2010-01-01

    Full Text Available Se realizada de forma inadequada, a fertigação pode levar à salinização do solo ou lixiviação dos nutrientes, com a consequente contaminação do lençol freático. Neste sentido, se propõe, no presente estudo, um índice para determinar a uniformidade de distribuição de amônio, nitrato, potássio e fósforo, ao longo de colunas de Latossolos fertigadas, com o objetivo de nortear o manejo adequado da fertigação. Este índice foi calculado a partir de dados coletados em um ensaio de laboratório, seguindo-se um fatorial 4 x (1 + 6, ou seja, quatro Latossolos de Minas Gerais (dois Latossolos Vermelho-Amarelos distróficos, um Latossolo Vermelho distroférrico e um Latossolo Vermelho distrófico, uma testemunha (aplicação de água deionizada e seis formas de aplicação de 1 mmol c de N-NH4+, 1 mmol c de N-NO3-, 2 mmol c de K e 2 mmol c dm-3 de P. Calcularam-se os coeficientes de variação para o teor de cada nutriente, ao longo das colunas e a relação entre o teor médio e o maior teor do nutriente (índice de uniformidade de distribuição de nutrientes considerando-se o solo e o tratamento. Concluiu-se, portanto, que a relação maior teor, teor médio é um índice de uniformidade de distribuição de nutrientes adequado para avaliar a movimentação de íons com maior mobilidade no solo, como nitrato, amônio e potássio. O coeficiente de variação é menos adequado para mostrar a uniformidade de distribuição dos nutrientes.Fertigation if conducted inadequately may cause soil salinization and consequently leaching of nutrients can pollute ground water. An index is proposed to determine the uniformity of distribution of ammonium, nitrate, potassium and phosphorus in columns of fertigated Oxisols, which relates the highest content of the nutrient in a column segment with the mean nutrient content in the experimental unit. The higher the index value, the more irregular is the nutrient distribution. This index was calculated

  4. Cover crops affecting levels of ammonium and nitrate in the soil and upland rice developmentPlantas de cobertura afetando os níveis de nitrato e amônio no solo e o desenvolvimento do arroz de terras altas

    Directory of Open Access Journals (Sweden)

    Adriano Stephan Nascente

    2013-10-01

    Full Text Available The use of cover crops in no-tillage systems (NTS increases the levels of organic matter and could increase the nitrogen content of the soil, contributing to reduce fertilizers costs. The knowledge of these processes is fundamental for deciding whether cover crops can be effectively incorporated into the agricultural production system. The objective of this study was to evaluate the effect of cover crop species on the levels of nitrate and ammonium in the soil in early upland rice development, as well upland rice yield. A field experiment was performed and treatments consisted of growing rice on five cover crops (Panicum maximum, Brachiaria ruziziensis, Brachiaria brizantha, millet and fallow in an NTS and two control treatments (Brachiaria brizantha and fallow under a conventional tillage system, CTS, (one plowing and two disking. The experimental design was a complete randomized block with three replications. The soil samples were collected during a period of six weeks (0, 7, 14, 21, 28 and 35 days in relation to upland rice sowing. The cover crops Brachiaria brizantha, Panicum maximum and Brachiaria ruziziensis in the NTS and B. brizantha fallow incorporated into the CTS favored higher levels of nitrate in the soil. In contrast, B. brizantha and fallow in the CTS and millet and P. maximum in the NTS favored the buildup of high levels of ammonium in the soil. The treatments under the plowed cover crops millet and fallow allowed for a higher upland rice yield. The tillage system and nature of the cover crops could be used to achieve the desired levels and forms of nitrogen in soil. O uso de plantas de cobertura no sistema plantio direto (SPD aumenta os níveis de matéria orgânica e pode ajudar a aumentar os teores de nitrogênio no solo contribuindo para reduzir os custos de fertilizantes. O conhecimento desse processo é fundamental para que as plantas de cobertura possam ser efetivamente incorporadas aos sistemas de produção agrícola. O

  5. Characterization of the winter midwestern particulate nitrate bulge.

    Science.gov (United States)

    Pitchford, Marc L; Poirot, Richard L; Schichtel, Bret A; Maim, William C

    2009-09-01

    A previously unobserved multi-state region of elevated particulate nitrate concentration was detected as a result of the expansion of the Interagency Monitoring of Protected Visual Environments (IMPROVE) network of remote-area particulate matter (PM) speciation monitoring sites into the midwestern United States that began in 2002. Mean winter ammonium nitrate concentrations exceed 4 microg/m3 in a region centered in Iowa, which makes it responsible for as much as half of the particle light extinction. Before these observations, particulate nitrate in the United States was only observed to be a dominant component of the fine PM (PM2.5) in parts of California and some urban areas. Comparisons of the spatial patterns of particulate nitrate with spatial patterns of ammonia and nitrogen oxide emissions suggest that the nitrate bulge is the result of the high emissions of ammonia associated with animal agriculture in the Midwest. Nitrate episodes at several locations in the eastern United States are shown to be associated with transport pathways over the Midwest, suggesting long-range transport of either ammonia or ammonium nitrate. Thermodynamic equilibrium modeling conducted by others on data from the Midwest shows the relative importance of atmospheric ammonia and nitric acid in the production of PM2.5. This is a particular concern as the sulfur dioxide emissions in the United States are reduced, which increases the amount of ammonia available for ammonium nitrate production. PMID:19785273

  6. Responses of barley root and shoot proteomes to long‐term nitrogen deficiency, short‐term nitrogen starvation and ammonium

    DEFF Research Database (Denmark)

    Laurell Blom Møller, Anders; Pedas, Pai; Andersen, Birgit;

    2011-01-01

    plants grown hydroponically for 33 d with 5 mm nitrate, plants grown under N deficiency (0.5 mm nitrate, 33 d) or short‐term N starvation (28 d with 5 mm nitrate followed by 5 d with no N source) were compared. N deficiency caused changes in C and N metabolism and ascorbate‐glutathione cycle enzymes in...... shoots and roots. N starvation altered proteins of amino acid metabolism in roots. Both treatments caused proteome changes in roots that could affect growth. Shoots of plants grown with ammonium as N source (28 d with 5 mm nitrate followed by 5 d with 5 mm ammonium) showed responses similar to N...

  7. Soil nitrate reducing processes – drivers, mechanisms for spatial variation, and significance for nitrous oxide production

    OpenAIRE

    Giles, Madeline; Morley, Nicholas; Baggs, Elizabeth M; Daniell, Tim J.

    2012-01-01

    The microbial processes of denitrification and dissimilatory nitrate reduction to ammonium (DNRA) are two important nitrate reducing mechanisms in soil, which are responsible for the loss of nitrate ( NO 3 − ) and production of the potent greenhouse gas, nitrous oxide (N2O). A number of factors are known to control these processes, including O2 concentrations and moisture content, N, C, pH, and the size and community structure of nitrate reducing organisms responsible for the processes. There...

  8. Soil nitrate reducing processes – drivers, mechanisms for spatial variation and significance for nitrous oxide production

    OpenAIRE

    TimJohnDaniell; MadelineEleanoreGiles

    2012-01-01

    The microbial processes of denitrification and dissimilatory nitrate reduction to ammonium (DNRA) are two important nitrate reducing mechanisms in soil, which are responsible for the loss of nitrate (NO3-¬) and production of the potent greenhouse gas, nitrous oxide (N2O). A number of factors are known to control these processes, including O2 concentrations and moisture content, N, C, pH and the size and community structure of nitrate reducing organisms responsible for the processes. Ther...

  9. Ecological Physiology of Synechococcus sp. Strain SH-94-5, a Naturally Occurring Cyanobacterium Deficient in Nitrate Assimilation

    OpenAIRE

    Miller, Scott R.; Castenholz, Richard W.

    2001-01-01

    Synechococcus sp. strain SH-94-5 is a nitrate assimilation-deficient cyanobacterium which was isolated from an ammonium-replete hot spring in central Oregon. While this clone could grow on ammonium and some forms of organic nitrogen as sole nitrogen sources, it could not grow on either nitrate or nitrite, even under conditions favoring passive diffusion. It was determined that this clone does not express functional nitrate reductase or nitrite reductase and that the lack of activity of either...

  10. Sugar transport and nitrate reductase activity rate in roots affect plant adaptation to cold and warm climate plants

    OpenAIRE

    Kafkafi, Uzi

    2009-01-01

    Nitrogen metabolism in the root is controlled by 2 fluxes: 1) nitrate intake from the external solution. 2) Transport of sugar from the leaves. Nitrate reduction to ammonium or direct ammonium uptake produce ammonia in the root cell. When the rate of sugar transport to root cells is slower than their sugar consumption for respiration, ammonia will accumulate and the root cells will die from ammonia toxicity. In nature, plants can be defined with regard to the activity of their root nitrate re...

  11. Adamantane-1-ammonium acetate

    Directory of Open Access Journals (Sweden)

    Elise J. C. de Vries

    2011-06-01

    Full Text Available In the title compound, C10H18N+·C2H3O2−, the ammonium H atoms of the cation are linked to three acetate anions via N—H...O hydrogen bonds, forming a chain structure extending along the b axis.

  12. 78 FR 32690 - Certain Ammonium Nitrate From Ukraine

    Science.gov (United States)

    2013-05-31

    ....2(f)). Background The Commission instituted this review on June 1, 2012 (77 FR 32669) and determined on October 17, 2012 that it would conduct a full review (77 FR 65015, October 24, 2012). Notice of... Commission, Washington, DC, and by publishing the notice in the Federal Register on October 24, 2012 (77...

  13. Nitrate removal by electro-bioremediation technology in Korean soil

    International Nuclear Information System (INIS)

    The nitrate concentration of surface has become a serious concern in agricultural industry through out the world. In the present study, nitrate was removed in the soil by employing electro-bioremediation, a hybrid technology of bioremediation and electrokinetics. The abundance of Bacillus spp. as nitrate reducing bacteria were isolated and identified from the soil sample collected from a greenhouse at Jinju City of Gyengsangnamdo, South Korea. The nitrate reducing bacterial species were identified by 16 s RNA sequencing technique. The efficiency of bacterial isolates on nitrate removal in broth was tested. The experiment was conducted in an electrokinetic (EK) cell by applying 20 V across the electrodes. The nitrate reducing bacteria (Bacillus spp.) were inoculated in the soil for nitrate removal process by the addition of necessary nutrient. The influence of nitrate reducers on electrokinetic process was also studied. The concentration of nitrate at anodic area of soil was higher when compared to cathode in electrokinetic system, while adding bacteria in EK (EK + bio) system, the nitrate concentration was almost nil in all the area of soil. The bacteria supplies electron from organic degradation (humic substances) and enhances NO3- reduction (denitrification). Experimental results showed that the electro-bio kinetic process viz. electroosmosis and physiological activity of bacteria reduced nitrate in soil environment effectively. Involvement of Bacillus spp. on nitrification was controlled by electrokinetics at cathode area by reduction of ammonium ions to nitrogen gas. The excellence of the combined electro-bio kinetics technology on nitrate removal is discussed.

  14. Efeito do nitrato e amônio sobre o crescimento e eficiência de utilização do nitrogênio em mandioca Effect of nitrate and ammonium on growth and efficiency of nitrogen use by cassava plants

    Directory of Open Access Journals (Sweden)

    Jailson Lopes Cruz

    2006-01-01

    Full Text Available Desenvolveu-se o presente estudo visando-se avaliar o efeito da fonte nitrogenada sobre o acúmulo de matéria seca e a absorção, distribuição e utilização de nitrogênio em mandioca. Para a instalação do experimento utilizou-se a variedade Cigana preta, cultivada em solução nutritiva e em vasos com capacidade para 11,0 L. O nível de nitrogênio na solução foi de 12 mol m-3 e os tratamentos consistiram de cinco proporções de NO3-:NH4+ , conforme segue: 12:0, 9:3, 6:6, 3:9 e 0:12 mol m-3. No encerramento do experimento, que ocorreu 90 dias após o plantio, verificou-se que as menores quantidades de massa seca total foram obtidas para as plantas cultivadas tendo apenas nitrato ou amônio como fonte de nitrogênio. Nesse aspecto, o amônio foi mais prejudicial ao crescimento do que a fonte nítrica. A concentração de NH4+ livre no tecido vegetal foi maior para as raízes de absorção, seguida pelas folhas e raízes de armazenamento. A eficiência de absorção de nitrogênio foi maior para as plantas cultivadas sob as maiores proporções de NH4+. Os resultados evidenciaram que a cultura da mandioca cresce melhor quando ocorrer na solução de crescimento uma mistura de NO3- e NH4+, principalmente nas proporções de 9:3 e 6:6 mol m-3.This study was carried out to evaluate the effect of nitrogen source on dry mass accumulation and absorption, distribution and also use of nitrogen by cassava plants. Cigana Preta cultivar plants were grown in nutrient solutions set up in 11.0 L containers. Nitrogen concentration in solutions was 12 mol m-3. Treatments included five combinations of NO3-:NH4+ , that is, 12:0, 9:3, 6:6, 3:9 and 0:12 mol m-3. Aftert 90 days the dry mass was determined. The lowest total dry mass values were obtained for plants grown with just nitrate or ammonium as nitrogen source. In this sence, ammonium affected growth more than the nitric source. The concentration of free NH4+ was higher for absorption in roots

  15. Nitrate and ammonia as nitrogen sources for deep subsurface microorganisms.

    Science.gov (United States)

    Kutvonen, Heini; Rajala, Pauliina; Carpén, Leena; Bomberg, Malin

    2015-01-01

    We investigated the N-utilizing bacterial community in anoxic brackish groundwater of the low and intermediate level nuclear waste repository cave in Olkiluoto, Finland, at 100 m depth using (15)N-based stable isotope probing (SIP) and enrichment with (14∕15)N-ammonium or (14∕15)N-nitrate complemented with methane. Twenty-eight days of incubation at 12°C increased the concentration of bacterial 16S rRNA and nitrate reductase (narG) gene copies in the substrate amended microcosms simultaneously with a radical drop in the overall bacterial diversity and OTU richness. Hydrogenophaga/Malikia were enriched in all substrate amended microcosms and Methylobacter in the ammonium and ammonium+methane supplemented microcosms. Sulfuricurvum was especially abundant in the nitrate+methane treatment and the unamended incubation control. Membrane-bound nitrate reductase genes (narG) from Polarimonas sp. were detected in the original groundwater, while Burkholderia, Methylibium, and Pseudomonas narG genes were enriched due to substrate supplements. Identified amoA genes belonged to Nitrosomonas sp. (15)N-SIP revealed that Burkholderiales and Rhizobiales clades belonging to the minority groups in the original groundwater used (15)N from ammonium and nitrate as N source indicating an important ecological function of these bacteria, despite their low number, in the groundwater N cycle in Olkiluoto bedrock system. PMID:26528251

  16. Nitrate and ammonia as nitrogen sources for deep subsurface microorganisms

    Directory of Open Access Journals (Sweden)

    Heini eKutvonen

    2015-10-01

    Full Text Available We investigated the N-utilizing bacterial community in anoxic brackish groundwater of the low and intermediate level nuclear waste repository cave in Olkiluoto, Finland, at 100 m depth using 15N-based stable isotope probing (SIP and enrichment with 14/15N-ammonium or 14/15N-nitrate complemented with methane. 28 days of incubation at 12°C increased the concentration of bacterial 16S rRNA and nitrate reductase (narG gene copies in the substrate amended microcosms simultaneously with a radical drop in the overall bacterial diversity and OTU richness. Hydrogenophaga/Malikia were enriched in all substrate amended microcosms and Methylobacter in the ammonium and ammonium+methane supplemented microcosms. Sulfuricurvum was especially abundant in the nitrate+methane treatment and the unamended incubation control. Membrane-bound nitrate reductase genes (narG from Polarimonas sp. were detected in the original groundwater, while Burkholderia, Methylibium and Pseudomonas narG genes were enriched due to substrate supplements. Identified amoA genes belonged to Nitrosomonas sp. 15N-SIP revealed that Burkholderiales and Rhizobiales clades belonging to the minority groups in the original groundwater used 15N from ammonium and nitrate as N source indicating an important ecological function of these bacteria, despite their low number, in the groundwater N cycle in Olkiluoto bedrock system.

  17. Nitrate and ammonia as nitrogen sources for deep subsurface microorganisms

    Science.gov (United States)

    Kutvonen, Heini; Rajala, Pauliina; Carpén, Leena; Bomberg, Malin

    2015-01-01

    We investigated the N-utilizing bacterial community in anoxic brackish groundwater of the low and intermediate level nuclear waste repository cave in Olkiluoto, Finland, at 100 m depth using 15N-based stable isotope probing (SIP) and enrichment with 14∕15N-ammonium or 14∕15N-nitrate complemented with methane. Twenty-eight days of incubation at 12°C increased the concentration of bacterial 16S rRNA and nitrate reductase (narG) gene copies in the substrate amended microcosms simultaneously with a radical drop in the overall bacterial diversity and OTU richness. Hydrogenophaga/Malikia were enriched in all substrate amended microcosms and Methylobacter in the ammonium and ammonium+methane supplemented microcosms. Sulfuricurvum was especially abundant in the nitrate+methane treatment and the unamended incubation control. Membrane-bound nitrate reductase genes (narG) from Polarimonas sp. were detected in the original groundwater, while Burkholderia, Methylibium, and Pseudomonas narG genes were enriched due to substrate supplements. Identified amoA genes belonged to Nitrosomonas sp. 15N-SIP revealed that Burkholderiales and Rhizobiales clades belonging to the minority groups in the original groundwater used 15N from ammonium and nitrate as N source indicating an important ecological function of these bacteria, despite their low number, in the groundwater N cycle in Olkiluoto bedrock system. PMID:26528251

  18. Effect of Controlled-release Urea Combined with Common Urea on the Grain Yields of Summer Maize and Distribution of Soil Ammonium and Nitrate Content%控释掺混肥对夏玉米产量及土壤硝态氮和铵态氮分布的影响

    Institute of Scientific and Technical Information of China (English)

    李伟; 李絮花; 唐慎欣; 李海燕; 刘旭凤; 彭强

    2011-01-01

    通过田间试验研究释放期60 d的水基包膜尿素与普通尿素常规施肥用量下不同比例配合追施对夏玉米产量、肥料利用率、氮肥农学利用率、氮肥偏生产力、氮素收获指数、氮素积累量及0-60 cm土壤硝铵态氦含量动态分布的影响.结果表明:各控释掺混处理对夏玉米的产量、肥料利用率、氮肥农学利用率、氮肥偏生产力及氮素收获指数较常规施肥都有不同程度的提高,以控氮比50%处理最佳,产量和氮肥利用率分别比对照的提高9.43%和24.69%,达到显著水平;各控释掺混处理0-60 cm土壤都保持较高的硝态氮含量,至后期较常规施肥的略高,满足了玉米的生长.玉米各时期土壤铵态氮含量大致以高控氮比处理的含量高,差异不明显,但显著高于常规施肥处理的.控氮比50%处理更适合本区域玉米生产.%Field experiment were carried out on grain yield of summer maize to determine the effect of different proportions of water-base controlled-release coated urea of 60 d release duration combined with conventional urea as topdressing on nitrogen utilization, nitrogen agronomic efficiency, nitrogen partial productivity, nitrogen harvest index and nitrogen accumulation. Dynamic distribution of nitrate content in soil was also studied. The findings indicated that the treatment of controlled-release urea combined with conventional urea (CRUCU)was remarkably higher than the ones used urea alone in various degree in maize yield, fertilizer utilization, nitrogen agronomic efficiency, productivity and nitrogen partial nitrogen harvest index, and the treatment used 50% controlled-release coated urea was superior to other ones. Its yield was increased by 9. 43% than the treatment used urea alone, while nitrogen utilization was 24. 69%. Both differences reached significant level. The nitrate nitrogen content of treatment of CRUCU was sufficient in 0 - 60 cm depth in soil layer throughout the later growth

  19. Nitrite-Responsive Activation of the Nitrate Assimilation Operon in Cyanobacteria Plays an Essential Role in Up-Regulation of Nitrate Assimilation Activities under Nitrate-Limited Growth Conditions

    OpenAIRE

    Aichi, Makiko; Maeda, Shin-Ichi; Ichikawa, Kazuhiro; Omata, Tatsuo

    2004-01-01

    NtcB of the cyanobacterium Synechococcus elongatus strain PCC 7942 is a LysR family protein that enhances expression of the nitrate assimilation operon (nirA operon) in response to the presence of nitrite, an intermediate of assimilatory nitrate reduction. Inactivation of ntcB in this cyanobacterium specifically abolishes the nitrite responsiveness of nirA operon expression, but under nitrate-replete conditions (wherein negative feedback by intracellularly generated ammonium prevails over the...

  20. Ammonium Uptake by Phytoplankton Regulates Nitrification in the Sunlit Ocean

    OpenAIRE

    Smith, Jason M.; Chavez, Francisco P.; Francis, Christopher A.

    2014-01-01

    Nitrification, the microbial oxidation of ammonium to nitrate, is a central part of the nitrogen cycle. In the ocean's surface layer, the process alters the distribution of inorganic nitrogen species available to phytoplankton and produces nitrous oxide. A widely held idea among oceanographers is that nitrification is inhibited by light in the ocean. However, recent evidence that the primary organisms involved in nitrification, the ammonia-oxidizing archaea (AOA), are present and active throu...

  1. Potassium-strontium amd ammonium-strontium tripolyphosphates

    International Nuclear Information System (INIS)

    Preparation of low-soluble compounds during interaction of potassium and ammonium tripolyphosphates and strontium nitrate in aqueous solutions (0.1-1.0 mol.% concentration, 20 deg C temperature) is investigated. Crystal hydrates KSr2P3O10x7H2O, NH4Sr2P3O10x5H2O and amorphous salt Sr5(P3O10)2xXH2O (X=10-12) are extracted

  2. Paliperidonium nitrate

    Directory of Open Access Journals (Sweden)

    Jingshui Ge

    2012-10-01

    Full Text Available In the title molecular salt (systematic name: 3-{2-[4-(6-fluoro-1,2-benzoxazol-3-ylpiperidin-1-yl]ethyl}-9-hydroxy-2-methyl-1,6,7,8,9,9a-hexahydropyrido[1,2-a]pyrimidin-4-one nitrate, C23H29FN4O3+·NO3−, the piperidine ring displays a chair conformation and its N atom is protonated; the N—H bond is in an axial orientation. The ring bearing the hydroxy group exhibits a half-chair conformation. The hydroxy group as well as the adjacent methylene group are disordered over two sets of sites in a 0.823 (5:0.177 (5 ratio. In the crystal, O—H...N, O—H...O, N—H...O and N—H...N hydrogen bonds connect the components into a three-dimensional network.

  3. 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.

  4. Evidence for a plasma-membrane-bound nitrate reductase involved in nitrate uptake of Chlorella sorokiniana

    Science.gov (United States)

    Tischner, R.; Ward, M. R.; Huffaker, R. C.

    1989-01-01

    Anti-nitrate-reductase (NR) immunoglobulin-G (IgG) fragments inhibited nitrate uptake into Chlorella cells but had no affect on nitrate uptake. Intact anti-NR serum and preimmune IgG fragments had no affect on nitrate uptake. Membrane-associated NR was detected in plasma-membrane (PM) fractions isolated by aqueous two-phase partitioning. The PM-associated NR was not removed by sonicating PM vesicles in 500 mM NaCl and 1 mM ethylenediaminetetraacetic acid and represented up to 0.8% of the total Chlorella NR activity. The PM NR was solubilized by Triton X-100 and inactivated by Chlorella NR antiserum. Plasma-membrane NR was present in ammonium-grown Chlorella cells that completely lacked soluble NR activity. The subunit sizes of the PM and soluble NRs were 60 and 95 kDa, respectively, as determined by sodium-dodecyl-sulfate electrophoresis and western blotting.

  5. Effects of N Forms and Rates on Vegetable Growth and Nitrate Accumulation

    Institute of Scientific and Technical Information of China (English)

    WANG Zhao-Hui; LI Sheng-Xiu

    2003-01-01

    Experiments were carried out on a vegetable field with Peking cabbage (Brassica pekinensis (Lour.)Rupr.), cabbage (Brassica chinensis var. Oleifera Makino and nemoto), green cabbage (Brassica chinensis L.), spinach (Spinacia oleracea L.) and rape (Brassica campestris L.) to study the effects of N forms and N rates on their growth and nitrate accumulation. The results indicated that application of ammonium chloride,ammonium nitrate, sodium nitrate and urea significantly increased the yields and nitrate concentrations of Peking cabbage and spinach. Although no significant difference was found in the yields after application of the 4 N forms, nitrate N increased nitrate accumulation in vegetables much more than ammonium N. The vegetable yields were not increased continuously with N rate increase, and oversupply of N reduced the plant growth, leading to a yield decline. This trend was also true for nitrate concentrations in some vegetables and at some sampling times. However, as a whole, the nitrate concentrations in vegetables were positively correlated with N rates. Thus, addition of N fertilizer to soil was the major cause for increases in nitrate concentrations in vegetables. Nitrate concentrations were much higher in roots, stems and petioles than in blades at any N rate.

  6. 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.

  7. Sources of Nitrate Contamination in Groundwater Under Developing Asian Megacities

    Science.gov (United States)

    Umezawa, Y.; Hosono, T.; Onodera, S.; Siringan, F.; Buapeng, S.; Delinom, R. M.; Yoshimizu, C.; Tayasu, I.; Nagata, T.; Taniguchi, M.

    2008-12-01

    The status of nitrate, nitrite and ammonium contamination in the water systems, and the mechanisms controlling their sources, pathways, and distributions were investigated for the Southeast Asian cities of Metro Manila, Bangkok, and Jakarta. GIS-based monitoring and dual isotope approach (nitrate d15N and d18O) suggested that human waste via severe sewer leakage was the major source of nutrient contaminants in Metro Manila and Jakarta urban areas. Furthermore, the characteristics of the nutrient contamination differed depending on the agricultural land use pattern in the suburban areas. The exponential increase in nitrate d15N along with the nitrate reduction and clear d18O/d15N slopes of nitrate (~0.5) indicated the occurrence of denitrification. An anoxic subsurface system associated with the natural geological setting (e.g., the old tidal plain at Bangkok) and artificial pavement coverage served to buffer nitrate contamination via active denitrification and reduced nitrification. Our results showed that nitrate and ammonium contamination of the aquifers in Metro Manila, Bangkok, and Jakarta was not excessive, suggesting low risk of drinking groundwater to human health, at present. However, the increased nitrogen load and increased per capita gross domestic product (GDP) in these developing cities may increase this contamination in the very near future. Continuous monitoring and management of the groundwater system is needed to minimize groundwater pollution in these areas.

  8. Regulation of Expression of Nitrate and Dinitrogen Assimilation by Anabaena Species

    OpenAIRE

    Meeks, John C.; Wycoff, Keith L.; Chapman, John S.; Enderlin, Carol S.

    1983-01-01

    Anabaena sp. strain 7120 appeared more responsive to nitrogen control than A. cylindrica. Growth in the presence of nitrate strongly repressed the differentiation of heterocysts and fixation of dinitrogen in Anabaena sp. strain 7120, but only weakly in A. cylindrica. Nitrate assimilation by ammonium-grown cultures was strongly repressed in Anabaena sp. strain 7120, but less so in A. cylindrica. The repressive effect of nitrate on dinitrogen assimilation in Anabaena sp. strain 7120, compared t...

  9. Effect of high electron donor supply on dissimilatory nitrate reduction pathways in a bioreactor for nitrate removal

    DEFF Research Database (Denmark)

    Behrendt, Anna; Tarre, Sheldon; Beliavski, Michael;

    2014-01-01

    The possible shift of a bioreactor for NO3- removal from predominantly denitrification (DEN) to dissimilatory nitrate reduction to ammonium (DNRA) by elevated electron donor supply was investigated. By increasing the C/NO3- ratio in one of two initially identical reactors, the production of high ...

  10. 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.

  11. Root ABA Accumulation Enhances Rice Seedling Drought Tolerance under Ammonium Supply: Interaction with Aquaporins.

    Science.gov (United States)

    Ding, Lei; Li, Yingrui; Wang, Ying; Gao, Limin; Wang, Min; Chaumont, François; Shen, Qirong; Guo, Shiwei

    2016-01-01

    In previous studies, we demonstrated that ammonium nutrition enhances the drought tolerance of rice seedlings compared to nitrate nutrition and contributes to a higher root water uptake ability. It remains unclear why rice seedlings maintain a higher water uptake ability when supplied with ammonium under drought stress. Here, we focused on the effects of nitrogen form and drought stress on root abscisic acid (ABA) concentration and aquaporin expression using hydroponics experiments and stimulating drought stress with 10% PEG6000. Drought stress decreased the leaf photosynthetic rate and stomatal conductivity and increased the leaf temperature of plants supplied with either ammonium or nitrate, but especially under nitrate supply. After 4 h of PEG treatment, the root protoplast water permeability and the expression of root PIP and TIP genes decreased in plants supplied with ammonium or nitrate. After 24 h of PEG treatment, the root hydraulic conductivity, the protoplast water permeability, and the expression of some aquaporin genes increased in plants supplied with ammonium compared to those under non-PEG treatment. Root ABA accumulation was induced by 24 h of PEG treatment, especially in plants supplied with ammonium. The addition of exogenous ABA decreased the expression of PIP and TIP genes under non-PEG treatment but increased the expression of some of them under PEG treatment. We concluded that drought stress induced a down-regulation of aquaporin expression, which appeared earlier than did root ABA accumulation. With continued drought stress, aquaporin expression and activity increased due to root ABA accumulation in plants supplied with ammonium. PMID:27559341

  12. Method of processing nitrate-containing radioactive liquid wastes

    International Nuclear Information System (INIS)

    Purpose: To efficiently concentrate nitrate-containing low level radioactive liquid wastes by electrolytically dialyzing radioactive liquid wastes to decompose the nitrate salt by using an electrolytic cell comprising three chambers having ion exchange membranes and anodes made of special materials. Method: Nitrate-containing low level radioactive liquid wastes are supplied to and electrolytically dialyzed in a central chamber of an electrolytic cell comprising three chambers having cationic exchange membranes and anionic exchange membranes made of flouro-polymer as partition membranes, whereby the nitrate is decomposed to form nitric acid in the anode chamber and alkali hydroxide compound or ammonium hydroxide in the cathode chamber, as well as concentrate the radioactive substance in the central chamber. Coated metals of at least one type of platinum metal is used as the anode for the electrolytic cell. This enables efficient industrial concentration of nitrate-containing low level radioactive liquid wastes. (Yoshihara, H.)

  13. Increasing wheat production while decreasing nitrogen losses from ammonium bicarbonate

    International Nuclear Information System (INIS)

    The objectives of a 4-year field experiment were i) to investigate the effects of rate and timing of application of ammonium bicarbonate on N-uptake efficiency by irrigated winter wheat, ii) to determine the fate of fertilizer N in wheat followed by maize, and iii) to study nitrate dynamics in the soil after N-fertilizer application to evaluate groundwater pollution by leaching. Nitrogen-application rates significantly affected wheat grain yields and straw dry matter. Grain yields were higher with 150 than with 225 kg N ha-1, whereas the highest fractional recoveries of N from ammonium bicarbonate occurred with 75 kg N ha-1 (38.5% in 1994-95 and 33.5% in 1996-97). On the basis of grain yield, N recovery and soil-N balance, ammonium bicarbonate at 150 kg N ha-1, was the optimum rate, when applied basally and as a top dressing to wheat. Subsequent yields of maize stover and grain were affected by N applied to the wheat, suggesting that fertilizer recommendations, in terms of rate and timing, should be made on the basis of effects on the cropping rotation as a whole. Water-holding capacity of the soil was poor, therefore large applications of N are likely to cause nitrate pollution of ground water. (author)

  14. Bacterial community responses to soil-injected liquid ammonium nutrition and effect of temperature on barley (Hordeum vulgare L.) grain yield formation

    OpenAIRE

    Matoka, Charles Mboya

    2007-01-01

    Injection of concentrated liquid ammonium nutrition into soil is an agricultural practice aimed at mitigating nitrogen losses. In Germany, it is referred to as controlled uptake long term ammonium nutrition (CULTAN) technique. Being an anion, nitrate is mobile in soil and thus is not bound to negatively charged surfaces of clay minerals or organic compounds. This may thus result in leaching and may eventually cause environmental pollution. Ammonium ions, on the other hand, may be unspecifical...

  15. Nitrate sources and sinks in Elkhorn Slough, California: Results from long-term continuous in situ nitrate analyzers

    Science.gov (United States)

    Chapin, T.P.; Caffrey, J.M.; Jannasch, H.W.; Coletti, L.J.; Haskins, J.C.; Johnson, K.S.

    2004-01-01

    Nitrate and water quality parameters (temperature, salinity, dissolved oxygen, turbidity, and depth) were measured continuously with in situ NO 3 analyzers and water quality sondes at two sites in Elkhorn Slough in Central California. The Main Channel site near the mouth of Elkhorn Slough was sampled from February to September 2001. Azevedo Pond, a shallow tidal pond bordering agricultural fields further inland, was sampled from December 1999 to July 2001. Nitrate concentrations were recorded hourly while salinity, temperature, depth, oxygen, and turbidity were recorded every 30 min. Nitrate concentrations at the Main Channel site ranged from 5 to 65 ??M. The propagation of an internal wave carrying water from ???100 m depth up the Monterey Submarine Canyon and into the lower section of Elkhorn Slough on every rising tide was a major source of nitrate, accounting for 80-90% of the nitrogen load during the dry summer period. Nitrate concentrations in Azevedo Pond ranged from 0-20 ??M during the dry summer months. Nitrate in Azevedo Pond increased to over 450 ??M during a heavy winter precipitation event, and interannual variability driven by differences in precipitation was observed. At both sites, tidal cycling was the dominant forcing, often changing nitrate concentrations by 5-fold or more within a few hours. Water volume flux estimates were combined with observed nitrate concentrations to obtain nitrate fluxes. Nitrate flux calculations indicated a loss of 4 mmol NO3 m -2 d-1 for the entire Elkhorn Slough and 1 mmol NO 3 m-2 d-1 at Azevedo Pond. These results suggested that the waters of Elkhorn Slough were not a major source of nitrate to Monterey Bay but actually a nitrate sink during the dry season. The limited winter data at the Main Channel site suggest that nitrate was exported from Elkhorn Slough during the wet season. Export of ammonium or dissolved organic nitrogen, which we did not monitor, may balance some or all of the NO 3 flux.

  16. Modeled Wet Nitrate Deposition

    Data.gov (United States)

    U.S. Environmental Protection Agency — Modeled data on nitrate wet deposition was obtained from Dr. Jeff Grimm at Penn State Univ. Nitrate wet depostion causes acidification and eutrophication of surface...

  17. Nitrate reductase, nitrite reductase, glutamine synthetase, and glutamate synthase expression and activity in response to different nitrogen sources in nitrogen-starved wheat seedlings.

    Science.gov (United States)

    Balotf, Sadegh; Kavoosi, Gholamreza; Kholdebarin, Bahman

    2016-03-01

    The objective of this study was to examine the expression and activity of nitrate reductase (NR, EC 1.7.1.1), nitrite reductase (NiR, EC 1.7.2.2), glutamine synthetase (GS, EC 6.3.1.2), and glutamate synthase (GOGAT, EC 1.4.7.1) in response to potassium nitrate, ammonium chloride, and ammonium nitrate in nitrogen-starved wheat seedlings. Plants were grown in standard nutrient solution for 17 days and then subjected to nitrogen starvation for 7 days. The starved plants were supplied with potassium nitrate ammonium nitrate and ammonium chloride (50 mM) for 4 days and the leaves were harvested. The relative expression of NR, NiR, GS, and GOGAT as well as the enzyme activities were investigated. Nitrogen starvation caused a significant decrease both in transcript levels and in NR, NiR, GS, and GOGAT activities. Potassium nitrate and ammonium nitrate treatments restored NR, NiR, GS, and GOGAT expressions and activities. Ammonium chloride increased only the expressions and activities of GS and GOGAT in a dose-dependent manner. The results of our study highlight the differential effects between the type and the amount of nitrogen salts on NR, NiR, GS, and GOGAT activities in wheat seedlings while potassium nitrate being more effective. PMID:25676153

  18. Nitrate-transformations during simulated drought on a restored floodplain

    Science.gov (United States)

    Hoagland, B.; Russo, T. A.; Schmidt, C. M.; Tran, D.

    2015-12-01

    Water resources in the California Central Valley face challenges due to recurring drought, aging levee systems, and nitrate contamination. As decisions are made to restore floodplain connectivity, soil microbial metabolic pathways such as denitrification, anaerobic ammonium oxidation (anammox), and dissimilatory nitrate reduction to ammonium (DNRA) transform nitrate under saturated soil conditions and may each affect downstream water quality. However, few studies have quantified the contribution of all three pathways to nitrate retention in freshwater systems, and specifically in restored floodplains. Additionally, no former studies quantify the rates of these microbial nitrate transformations during floods after prolonged periods of drought. To test how flood duration impacts nitrogen cycling we added 15N-enriched tracer to soil mesocosms to measure denitrification, anammox, and DNRA transformation rates. In July 2015, we extracted seven soil mesocosms from the floodplain and riverbed of the Lower Cosumnes River in the San Joaquin Basin of California. Cosumnes River water enriched with 15N-NO3- tracer was pumped into each mesocosm at a constant rate simulating flood durations of 20 h, 30 h, and 96 h. Samples were collected from the surface water, soil pore water, drain water, and sediment for measurements of NO3-, NO2-, NH4+, gas isotopes, and DNA extraction. This study aims to demonstrate the relevance of anammox and DNRA to total nitrate retention and characterize the hydrologic conditions most favorable to each pathway.

  19. Tidal pumping facilitates dissimilatory nitrate reduction in intertidal marshes

    Science.gov (United States)

    Zheng, Yanling; Hou, Lijun; Liu, Min; Liu, Zhanfei; Li, Xiaofei; Lin, Xianbiao; Yin, Guoyu; Gao, Juan; Yu, Chendi; Wang, Rong; Jiang, Xiaofen

    2016-02-01

    Intertidal marshes are alternately exposed and submerged due to periodic ebb and flood tides. The tidal cycle is important in controlling the biogeochemical processes of these ecosystems. Intertidal sediments are important hotspots of dissimilatory nitrate reduction and interacting nitrogen cycling microorganisms, but the effect of tides on dissimilatory nitrate reduction, including denitrification, anaerobic ammonium oxidation and dissimilatory nitrate reduction to ammonium, remains unexplored in these habitats. Here, we use isotope-tracing and molecular approaches simultaneously to show that both nitrate-reduction activities and associated functional bacterial abundances are enhanced at the sediment-tidal water interface and at the tide-induced groundwater fluctuating layer. This pattern suggests that tidal pumping may sustain dissimilatory nitrate reduction in intertidal zones. The tidal effect is supported further by nutrient profiles, fluctuations in nitrogen components over flood-ebb tidal cycles, and tidal simulation experiments. This study demonstrates the importance of tides in regulating the dynamics of dissimilatory nitrate-reducing pathways and thus provides new insights into the biogeochemical cycles of nitrogen and other elements in intertidal marshes.

  20. Nitrate accumulation in spinach

    NARCIS (Netherlands)

    Steingröver, Eveliene Geertruda

    1986-01-01

    Leafy vegetables, like spinach, may contain high concentrations of nitrate. In the Netherlands, about 75% of mean daily intake of nitrate orginates from the consumption of vegatables. Hazards to human health are associated with the reduction of nitrate to nitrite. Acute nitrite poisoning causes meth

  1. Nitrate paradigm does not hold up for sugarcane.

    Directory of Open Access Journals (Sweden)

    Nicole Robinson

    Full Text Available Modern agriculture is based on the notion that nitrate is the main source of nitrogen (N for crops, but nitrate is also the most mobile form of N and easily lost from soil. Efficient acquisition of nitrate by crops is therefore a prerequisite for avoiding off-site N pollution. Sugarcane is considered the most suitable tropical crop for biofuel production, but surprisingly high N fertilizer applications in main producer countries raise doubt about the sustainability of production and are at odds with a carbon-based crop. Examining reasons for the inefficient use of N fertilizer, we hypothesized that sugarcane resembles other giant tropical grasses which inhibit the production of nitrate in soil and differ from related grain crops with a confirmed ability to use nitrate. The results of our study support the hypothesis that N-replete sugarcane and ancestral species in the Andropogoneae supertribe strongly prefer ammonium over nitrate. Sugarcane differs from grain crops, sorghum and maize, which acquired both N sources equally well, while giant grass, Erianthus, displayed an intermediate ability to use nitrate. We conclude that discrimination against nitrate and a low capacity to store nitrate in shoots prevents commercial sugarcane varieties from taking advantage of the high nitrate concentrations in fertilized soils in the first three months of the growing season, leaving nitrate vulnerable to loss. Our study addresses a major caveat of sugarcane production and affords a strong basis for improvement through breeding cultivars with enhanced capacity to use nitrate as well as through agronomic measures that reduce nitrification in soil.

  2. Use of the δ18O and δ15N of nitrate to determine sources of nitrate in early spring runoff in forested catchments

    International Nuclear Information System (INIS)

    Many upland catchments have increased nitrate and hydrogen ion concentrations in stream water during the early snowmelt period. The dominant source of this nitrate is not well known, but likely contributors include atmospheric deposition of nitrate and ammonium in the snowpack, and soil derived nitrate. Pilot studies initiated in three catchments during the 1994 snowmelt season show that analysis of both the δ18O and δ15N of nitrate provides excellent separation of nitrate sources. Almost all the stream samples have nitrate δ18O and δ15N values within the range of the pre-melt soil and stream waters, suggesting that atmospheric nitrate eluted from the 1994 snowpack is a minor source of nitrate in early streamflow. Therefore, the nitrate eluted from the 1994 snowpack appears to go into storage, and most of the nitrate in streamflow during the period of potential acidification was derived from pre-melt sources. The δ18O of pre-melt nitrate in soil and stream waters is intermediate between the compositions of atmospheric and solid derived nitrate, indicating a mixture of sources. The enriched composition of the pre-melt nitrate suggests that either atmospheric nitrate is actually a dominant source of nitrate to the catchment on a yearly basis, or that there is recharge of shallow storage by percolating snowmelt during midwinter thaws. In either case, the nitrate pulse in stream water during early melt appears to be largely derived from precipitation from previous months or years that is flushed from storage. (author). 12 refs, 2 figs

  3. Tripolyphosphates of potassium-cadmium and ammonium-cadmium

    International Nuclear Information System (INIS)

    Formation of barely soluble compounds during interaction of ammonium and potassium tripolyphosphates with cadmium nitrate in aqueous solutions (0.1-2.0 mol% concentration, the temperature 20 deg C), is investigated. KCd2P3O10x7H2O, NH4Cd2P3O10x7H2O crystallohydrates and Cd5(P3O10)2xhH2O (x=10-13) X-ray amorphous salt, that are dissolved in potassium and ammonium tripolyphosphate solution with formation of Cd2+:P3O105-=1:1 and 1:2 complexes, are separated. In K5P3O10-Cd(NO3)2-H2O system Cd2+:P3O105-=1:1 complex is crystallized in a mixture with varied composition amorphous phase

  4. Effect of Nitrogen Form and pH of Nutrient Solution on the Shoot Concentration of Phosphorus, Nitrate, and Nitrogen of Spinach in Hydroponic Culture

    Directory of Open Access Journals (Sweden)

    N. Najafi

    2010-06-01

    Full Text Available In order to study the effect of nitrogen form and pH of nutrient solution on the shoot concentration of P, nitrate, organic N + inorganic ammonium, and total N of spinach, a factorial experiment was conducted with two factors including pH of nutrient solution in three levels (4.5, 6.5 and 8.0 and nitrate to ammonium ratio of nutrient solution in five levels (100:0, 75:25, 50:50, 25:75 and 0:100. This factorial experiment was carried out in a completely randomized design with four replications. Three seedlings of spinach plant (Spinacia oleracea L. Sirius cultivar were cultivated per pot and were nourished with 15 different nutrient solutions. The results showed that while the effect of nutrient solution pH on the shoot concentration of P, nitrate, and organic N + inorganic ammonium was significant, it was not significant on the shoot concentration of total N. By increasing the nutrient solution pH from 4.5 to 8.0, the shoot concentration of P and nitrate was significantly decreased, but the shoot concentration of organic N + inorganic ammonium, and total N did not change significantly. The main effect of nitrate to ammonium ratio of nutrient solution on the shoot concentration of P, nitrate, organic N + inorganic ammonium, and total N of spinach plant was significant. By increasing the ammonium concentration of nutrient solution, the shoot concentration of nitrate was significantly decreased, while the shoot concentration of P, organic N + inorganic ammonium, and total N of spinach plant was significantly increased. The effect of N form of nutrient solution on the shoot concentration and content of P, nitrate, and total N of spinach plant was dependent on the nutrient solution pH and vice versa. The greatest P concentration in spinach shoots was obtained in nitrate to ammonium ratio of 0:100 and pH of 8.0. The greatest spinach shoots nitrate concentration was found in nitrate to ammonium ratio of 100:0 and pH of 8.0, while the greatest

  5. Nitrate pollution of groundwater

    International Nuclear Information System (INIS)

    Concern about the possible health risks associated with the consumption of nitrate has led many countries, including South Africa, to propose that 10mg of nitrogen (as nitrate or nitrite) per liter should be the maximum allowable limit for domestic water supplies. Groundwater in certain parts of South Africa and Namibia contains nitrate in concentrations which exceed this limit. The CSIR's Natural Isotope Division has been studying the nitrogen isotope composition of the nitrate as an aid to investigation into the sources of this nitrate contamination

  6. Identification of Differentially Expressed Genes Induced by Ammonium Nitrogen in Rice Using mRNA Differential Display

    Institute of Scientific and Technical Information of China (English)

    ZHU Guo-hui; HUANG Zhuo-lie

    2008-01-01

    RNAs isolated from ammonium- and nitrate-treated rice leaves were used to screen differentially expressed genes through mRNA differential display. A total of 72 bands appeared significant differences and some of them were further confirmed by reverse Northern and Northem blot. The results showed that two genes, A-02 (Oryza sativa drought stress related mRNA) and A-03 (Zea mays partial mRNA for TFIIB-related protein) were highly up-regulated in the ammonium-fed rice leaves. The enzyme assays showed that the activities of the two anti-oxidative enzymes, catalase and peroxidase, and the content of a non-enzymic antioxidant, glutathione, were significantly higher in the ammonium-fed rice leaves than those in the nitrate-fed ones, indicating that the ammonium nutrition might be beneficial for rice plants to improve the stress resistance during growth and development.

  7. Nitrate decontamination through functionalized chitosan in brackish water.

    Science.gov (United States)

    Appunni, Sowmya; Rajesh, Mathur P; Prabhakar, Sivaraman

    2016-08-20

    N, N, N-Triethyl ammonium functionalized cross-linked chitosan beads (TEACCB) was prepared by alkylation of glutaraldehyde cross-linked chitosan beads to remove nitrate from brackish water. Physico-chemical characteristics of TEACCB were analyzed using FTIR, SEM, EDAX, TGA, DTA, BET surface area, swelling ratio and pHzpc. The maximum nitrate removal capacity of TEACCB was 2.26meq/g and is higher than other reported chitosan based adsorbents. Nitrate removal ratio in the presence and absence of common anions like chloride and sulphate demonstrated the selectively of TEACCB towards nitrate. The kinetic data of nitrate removal fitted well with the pseudo-second-order kinetic model. The thermodynamic parameters indicated that nitrate removal could be spontaneous and exothermic in nature. TEACCB was reused with 100% efficiency after regenerating with 0.05N HCl. Column study was carried out to remove nitrate from brackish water. These results are very significant to develop TEACCB based nitrate removal technology with great efficiency. PMID:27178960

  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. The effect of spatial heterogeneity on nitrate reduction in soil systems

    DEFF Research Database (Denmark)

    Pedersen, Lasse Lu

    hand governed by formation by oxidation of ammonia-N, and on the other hand by removal a removal by two dissimilatory nitrate reduction processes:denitrification, in which nitrate is converted to the gaseous compounds dinitrogen and nitrous oxide, and dissimilatory nitrate reduction to ammonium, DNRA...... nitrate, and can be assimilated into organic matter, effectively bypassing both denitrification and dinitrogen fixation and conserving nitrogen in the ecosystem. It is well established that soil is an extremely heterogeneous environment, not merely on a macroscopic level, but also on a microscopic level...

  10. Comparative DFT study of crystalline ammonium perchlorate and ammonium dinitramide.

    Science.gov (United States)

    Zhu, Weihua; Wei, Tao; Zhu, Wei; Xiao, Heming

    2008-05-22

    The electronic structure, vibrational properties, absorption spectra, and thermodynamic properties of crystalline ammonium perchlorate (AP) and ammonium dinitramide (ADN) have been comparatively studied using density functional theory in the local density approximation. The results shows that the p states for the two solids play a very important role in their chemical reaction. From the low frequency to high frequency region, ADN has more motion modes for the vibrational frequencies than AP. The absorption spectra of AP and ADN display a few, strong bands in the fundamental absorption region. The thermodynamic properties show that ADN is easier to decompose than AP as the temperature increases. PMID:18396853

  11. Nitrate aerosols today and in 2030: importance relative to other aerosol species and tropospheric ozone

    Directory of Open Access Journals (Sweden)

    S. E. Bauer

    2007-04-01

    Full Text Available Ammonium-nitrate aerosols are expected to become more important in the future atmosphere due to the expected increase in nitrate precursor emissions and the decline of ammonium-sulphate aerosols in wide regions of this planet. The GISS climate model is used in this study, including atmospheric gas- and aerosol phase chemistry to investigate current and future (2030, following the SRES A1B emission scenario atmospheric compositions. A set of sensitivity experiments was carried out to quantify the individual impact of emission- and physical climate change on nitrate aerosol formation. We found that future nitrate aerosol loads depend most strongly on changes that may occur in the ammonia sources. Furthermore, microphysical processes that lead to aerosol mixing play a very important role in sulphate and nitrate aerosol formation. The role of nitrate aerosols as climate change driver is analyzed and set in perspective to other aerosol and ozone forcings under pre-industrial, present day and future conditions. In the near future, year 2030, ammonium nitrate radiative forcing is about –0.14 W/m2 and contributes roughly 10% of the net aerosol and ozone forcing. The present day nitrate and pre-industrial nitrate forcings are –0.11 and –0.05 W/m2, respectively. The steady increase of nitrate aerosols since industrialization increases its role as a non greenhouse gas forcing agent. However, this impact is still small compared to greenhouse gas forcings, therefore the main role nitrate will play in the future atmosphere is as an air pollutant, with annual mean near surface air concentrations rising above 3 μg/m3 in China and therefore reaching pollution levels, like sulphate aerosols, in the fine particle mode.

  12. 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 (pH) alone, while salinity, [H+], temperature, and depth all played a role in predicting deep (>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.

  13. Nitrate and ammonia as nitrogen sources for deep subsurface microorganisms

    OpenAIRE

    Kutvonen, Heini; Rajala, Pauliina; Carpén, Leena; Bomberg, Malin

    2015-01-01

    We investigated the N-utilizing bacterial community in anoxic brackish groundwater of the low and intermediate level nuclear waste repository cave in Olkiluoto, Finland, at 100 m depth using 15N-based stable isotope probing (SIP) and enrichment with 14∕15N-ammonium or 14∕15N-nitrate complemented with methane. Twenty-eight days of incubation at 12°C increased the concentration of bacterial 16S rRNA and nitrate reductase (narG) gene copies in the substrate amended microcosms simultaneously with...

  14. Field determination of nitrate using nitrate reductase

    Energy Technology Data Exchange (ETDEWEB)

    Campbell, E.R.; Corrigan, J.S.; Campbell, W.H. [Nitrate Elimination Co., Inc., Lake Linden, MI (United States)

    1997-12-31

    Nitrate is routinely measured in a variety of substrates - water, tissues, soils, and foods - both in the field and in laboratory settings. The most commonly used nitrate test methods involve the reduction of nitrate to nitrite via a copper-cadmium reagent, followed by reaction of the nitrite with the Griess dye reagents. The resulting color is translated into a nitrate concentration by comparison with a calibrated color chart or comparator, or by reading the absorbance in a spectrophotometer. This basic method is reliable and sufficiently sensitive for many applications. However, the cadmium reagent is quite toxic. The trend today is for continued increase in concern for worker health and safety; in addition, there are increasing costs and logistical problems associated with regulatory constraints on transport and disposal of hazardous materials. Some suppliers have substituted a zinc-based reagent powder for the cadmium in an effort to reduce toxicity. We describe here an enzyme-based nitrate detection method as an improvement on the basic Griess method that demonstrates equal or superior sensitivity, superior selectivity, and is more environmentally benign. Comparisons between the enzyme-based method and some standard field test kits being used today are made.

  15. Heterogeneous-catalytic redox reactions in nitrate - formate systems

    International Nuclear Information System (INIS)

    It was found that an intensive destruction of various organic and mineral substances - usual components of aqueous waste solutions (oxalic acid, complexones, urea, hydrazine, ammonium nitrate, etc.) takes place under the conditions of catalytic denitration. Kinetics and mechanisms of urea and ammonium nitrate decomposition in the system HNO3 - HCOOH - Pt/SiO2 are comprehensively investigated. The behaviour of uranium, neptunium and plutonium under the conditions of catalytic denitration is studied. It is shown, that under the certain conditions the formic acid is an effective reducer of the uranium (VI), neptunium (VI, V) and plutonium (VI, IV) ions. Kinetics of heterogeneous-catalytic red-ox reactions of uranium (VI), neptunium (VI, V) and plutonium (VI, IV) with formic acid are investigated. The mechanisms of the appropriate reactions are evaluated. (authors)

  16. Effects of mineral dust on global atmospheric nitrate concentrations

    Science.gov (United States)

    Karydis, V. A.; Tsimpidi, A. P.; Pozzer, A.; Astitha, M.; Lelieveld, J.

    2016-02-01

    This study assesses the chemical composition and global aerosol load of the major inorganic aerosol components, focusing on mineral dust and aerosol nitrate. The mineral dust aerosol components (i.e., Ca2+, Mg2+, K+, Na+) and their emissions are included in the ECHAM5/MESSy Atmospheric Chemistry model (EMAC). Gas/aerosol partitioning is simulated using the ISORROPIA-II thermodynamic equilibrium model that considers K+, Ca2+, Mg2+, NH4+, Na+, SO42-, NO3-, Cl-, and H2O aerosol components. Emissions of mineral dust are calculated online by taking into account the soil particle size distribution and chemical composition of different deserts worldwide. Presence of metallic ions can substantially affect the nitrate partitioning into the aerosol phase due to thermodynamic interactions. The model simulates highest fine aerosol nitrate concentration over urban and industrialized areas (1-3 µg m-3), while coarse aerosol nitrate is highest close to deserts (1-4 µg m-3). The influence of mineral dust on nitrate formation extends across southern Europe, western USA, and northeastern China. The tropospheric burden of aerosol nitrate increases by 44 % when considering interactions of nitrate with mineral dust. The calculated global average nitrate aerosol concentration near the surface increases by 36 %, while the coarse- and fine-mode concentrations of nitrate increase by 53 and 21 %, respectively. Other inorganic aerosol components are affected by reactive dust components as well (e.g., the tropospheric burden of chloride increases by 9 %, ammonium decreases by 41 %, and sulfate increases by 7 %). Sensitivity tests show that nitrate aerosol is most sensitive to the chemical composition of the emitted mineral dust, followed by the soil size distribution of dust particles, the magnitude of the mineral dust emissions, and the aerosol state assumption.

  17. Thermal annealing of gamma irradiated ammonium chloride (Preprint no. RC-37)

    International Nuclear Information System (INIS)

    Ammonium chloride produces N2H4+ and Cl2 as the main radiolytic products on gamma irradiation. Thermal annealing has a marked effect on the stability of N2H4+ and Cl2. During the thermal annealing the chemical yield of nitrite and iodine was studied by dissolving irradiated ammonium chloride in aqueous sodium nitrate and potassium iodide respectively. The yield of iodine in isochronal annealing showed an exponential behaviour with temperature while that of nitrite showed a decrease and then increases at higher temperatures. The results are explained on the basis of dissociation and recombination of N2H4+ with temperature. (author). 3 refs., 2 figs

  18. 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

  19. Agricultural nitrate pollution

    DEFF Research Database (Denmark)

    Anker, Helle Tegner

    2015-01-01

    Despite the passing of almost 25 years since the adoption of the EU Nitrates Directive, agricultural nitrate pollution remains a major concern in most EU Member States. This is also the case in Denmark, although a fairly strict regulatory regime has resulted in almost a 50 per cent reduction...

  20. Nitrate aerosols today and in 2030: a global simulation including aerosols and tropospheric ozone

    OpenAIRE

    S. E. Bauer; Koch, D.; Unger, N.; Metzger, S. M.; Shindell, D. T.; Streets, D.G.

    2007-01-01

    Nitrate aerosols are expected to become more important in the future atmosphere due to the expected increase in nitrate precursor emissions and the decline of ammonium-sulphate aerosols in wide regions of this planet. The GISS climate model is used in this study, including atmospheric gas- and aerosol phase chemistry to investigate current and future (2030, following the SRES A1B emission scenario) atmospheric compositions. A set of sensitivity experiments was carried out to...

  1. Nitrate aerosols today and in 2030: a global simulation including aerosols and tropospheric ozone

    OpenAIRE

    S. E. Bauer; Koch, D.; Unger, N.; Metzger, S. M.; Shindell, D. T.; Streets, D.G.

    2007-01-01

    Nitrate aerosols are expected to become more important in the future atmosphere due to the expected increase in nitrate precursor emissions and the decline of ammonium-sulphate aerosols in wide regions of this planet. The GISS climate model is used in this study, including atmospheric gas- and aerosol phase chemistry to investigate current and future (2030, following the SRES A1B emission scenario) atmospheric compositions. A set of sensitivity experiments was carried out to quantify the indi...

  2. Influence of carbon source on nitrate removal by nitrate-tolerant Klebsiella oxytoca CECT 4460 in batch and chemostat cultures

    Energy Technology Data Exchange (ETDEWEB)

    Pinar, G.; Ramos, J.L. [Consejo Superior de Investigaciones Cientificas, Granada (Spain); Kovarova, K.; Egli, T. [Swiss Federal Inst. for Environmental Science and Technology, Duebendorf (Switzerland). Dept. of Microbiology

    1998-08-01

    The nitrate-tolerant organism Klebsiella oxytoca CECT-4460 tolerates nitrate at concentrations up to 1 M and is used to treat wastewater with high nitrate loads in industrial wastewater treatment plants. The authors studied the influence of the C source (glycerol or sucrose or both) on the growth rate and the efficiency of nitrate removal under laboratory conditions. With sucrose as the sole C source the maximum specific growth rate was 0.3 h{sup {minus}1}, whereas with glycerol it was 0.45 h{sup {minus}1}. In batch cultures K. oxytoca cells grown on sucrose or glycerol were able to immediately use sucrose as a sole C source, suggesting that sucrose uptake and metabolism were constitutive. In contrast, glycerol uptake occurred preferentially in glycerol-grown cells. Independent of the preculture conditions, when sucrose and glycerol were added simultaneously to batch cultures, the sucrose was used first, and once the supply of sucrose was exhausted, the glycerol was consumed. Utilization of nitrate as an N source occurred without nitrite of ammonium accumulation when glycerol was used, but nitrite accumulated when sucrose was used. In chemostat cultures K. oxytoca CECT 4460 efficiently removed nitrate without accumulation of nitrite or ammonium when sucrose, glycerol, or mixtures of these two C sources were used. The growth yields and the efficiencies of C and N utilization were determined at different growth rates in chemostat cultures. Regardless of the C source, yield carbon (Y{sub C}) ranged between 1.3 and 1.0 g (dry weight) per g of sucrose C or glycerol C consumed. Regardless of the specific growth rate and the C source, yield nitrogen (Y{sub N}) ranged from 17.2 to 12.5 g (dry weight) per g of nitrate N consumed.

  3. The effect of pH on the properties of ammonium uranate precipitated with gaseous ammonia

    International Nuclear Information System (INIS)

    Ammonium uranate (AU) powders were precipitated from a uranyl nitrate solution using gaseous ammonia to determine the effect of pH of precipitation on their composition and morphology. Increasing pH of precipitation increased the ammonia and nitrate contents and the specific surface area but decreased the crystallite size of the AU powders. The specific surface area was also increased by increasing the ammonia content of the powder. The composition and morphology of the powders were similar to those reported in the literature for AU precipitated with NH4OH. (author)

  4. 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)...

  5. 77 FR 50613 - Didecyl Dimethyl Ammonium Carbonate and Didecyl Dimethyl Ammonium Bicarbonate; Exemption From the...

    Science.gov (United States)

    2012-08-22

    ... AGENCY 40 CFR Part 180 Didecyl Dimethyl Ammonium Carbonate and Didecyl Dimethyl Ammonium Bicarbonate... Didecyl Dimethyl Ammonium Carbonate and Didecyl Dimethyl Ammonium Bicarbonate, jointly referred to as.... Background and Statutory Findings In the Federal Register of December 8, 2011 (76 FR 76674) (FRL-...

  6. [Synthesis, characterization and antimicrobial activity of konjac glucomannan derivative with quaternary ammonium salts].

    Science.gov (United States)

    Lei, Wan-Xue; Xu, Xia; Lin, Fang; Yang, Qin-Huan; Li, Zhen-Jun; Zhang, Ting-You

    2008-05-01

    Methacryloxylethyl tetradecyl dimethyl ammonium bromide was grafted onto konjac glucomannan using ceric ammonium nitrate as an initiator, and the konjac glucomannan derivative with quaternary ammonium salts was obtained. The konjac glucomannan derivative was investigated by hydrogen nuclear magnetic resonance spectroscopy (1H NMR), Fourier transform infrared spectroscopy (FTIR), differential scanning calorimeter (DSC), and Zeta sizer nano series. The antimicrobial properties of the konjac glucomannan derivative against selected microorganisms were tested by the quantitative suspension method. The results revealed that (1) methacryloxylethyl tetradecyl dimethyl ammonium bromide can be grafted onto the surface of the konjac glucomannan, and the percentage grafting increases with increasing the amount of methacryloxylethyl tetradecyl dimethyl ammonium bromide. (2) The Zeta potential showed that the isoelectric point of the konjac glucomannan and the modified konjac glucomannan is pH 4. 5 and pH 9. 9, respectively. The shift of the isoelectric point is due to the quaternary ammonium groups. (3) The obtained konjac glucomannan derivative has significant inhibition effect on the growth of microorganisms, and the bactericidal rates in 15 min for E. coil (8099), S. aureus (ATCC 6538) and C. albicans (ATCC10231) were 99.99%, 99.99% and 98.13%, respectively. PMID:18720795

  7. Ammonium assmilation in spruce ectomycorrhizas

    International Nuclear Information System (INIS)

    Assimilation of labelled NH4+ into amino acids has been followed in ectomycorrhizal roots of spruce. Over an 18 h period of NH4+ feeding, Gln, Glu and Ala became the most abundant amino acids. Gln was also the most highly labelled amino acid during the experiment, followed by Glu and Ala. This result indicates that Gln synthesis is an important ammonium utilization reaction in spruce mycorrhizas. Addition of MSX to NH4+ fed mycorrhizas caused an inhibition of Gln accumulation with a corresponding increase in Glu, Ala and Asn levels. The supply of MSX induced a sharp diminution of 15N enrichment in both amino and amido groups of glutamine. In contrast, the 15N incorporation into Glu and derivatives (Ala and Asp) remained very high. This study demonstrates that the fungal glutamate dehydrogenase is quite operative in spruce ectomycorrhizas since it is able to sustain ammonium assimilation when glutamine synthetase is inhibited

  8. Nitrate ammonification by Nautilia profundicola AmH: experimental evidence consistent with a free hydroxylamine intermediate.

    Directory of Open Access Journals (Sweden)

    Thomas E Hanson

    2013-07-01

    Full Text Available The process of nitrate reduction via nitrite controls the fate and bioavailability of mineral nitrogen within ecosystems; i.e. whether it is retained as ammonium (ammonification or lost as nitrous oxide or dinitrogen (denitrification. Here, we present experimental evidence for a novel pathway of microbial nitrate reduction, the reverse hydroxylamine:ubiquinone reductase module (reverse-HURM pathway. Instead of a classical ammonia-forming nitrite reductase that performs a 6 electron-transfer process, the pathway is thought to employ two catalytic redox modules operating in sequence: the reverse-HURM reducing nitrite to hydroxylamine followed by a hydroxylamine reductase that converts hydroxylamine to ammonium. Experiments were performed on Nautilia profundicola strain AmH, whose genome sequence led to the reverse-HURM pathway proposal. N. profundicola produced ammonium from nitrate, which was assimilated into biomass. Furthermore, genes encoding the catalysts of the reverse-HURM pathway were preferentially expressed during growth of N. profundicola on nitrate as an electron acceptor relative to cultures grown on polysulfide as an electron acceptor. Finally, nitrate-grown cells of N. profundicola were able to rapidly and stoichiometrically convert high concentrations of hydroxylamine to ammonium in resting cell assays. These experiments are consistent with the reverse-HURM pathway and a free hydroxylamine intermediate, but could not definitively exclude direct nitrite reduction to ammonium by the reverse-HURM with hydroxylamine as an off-pathway product. N. profundicola and related organisms are models for a new pathway of nitrate ammonification that may have global impact due to the wide distribution of these organisms in hypoxic environments and symbiotic or pathogenic associations with animal hosts.

  9. Agriculture causes nitrate fertilization of remote alpine lakes

    Science.gov (United States)

    Hundey, E. J.; Russell, S. D.; Longstaffe, F. J.; Moser, K. A.

    2016-02-01

    Humans have altered Earth's nitrogen cycle so dramatically that reactive nitrogen (Nr) has doubled. This has increased Nr in aquatic ecosystems, which can lead to reduced water quality and ecosystem health. Apportioning sources of Nr to specific ecosystems, however, continues to be challenging, despite this knowledge being critical for mitigation and protection of water resources. Here we use Δ17O, δ18O and δ15N from Uinta Mountain (Utah, USA) snow, inflow and lake nitrate in combination with a Bayesian-based stable isotope mixing model, to show that at least 70% of nitrates in aquatic systems are anthropogenic and arrive via the atmosphere. Moreover, agricultural activities, specifically nitrate- and ammonium-based fertilizer use, are contributing most (~60%) Nr, and data from other North American alpine lakes suggest this is a widespread phenomenon. Our findings offer a pathway towards more effective mitigation, but point to challenges in balancing food production with protection of important water resources.

  10. Supplementary calcium ameliorates ammonium toxicity by improving water status in agriculturally important species

    OpenAIRE

    Hernández-Gómez, Elvia; Valdez-Aguilar, Luis A.; Cartmill, Donita L.; Cartmill, Andrew D.; Alia-Tajacal, Irán

    2015-01-01

    Fertilization of agricultural plants with ammonium ( N H 4 + ) is often desirable because it is less susceptible to leaching than nitrate ( N O 3 − ) , reducing environmental pollution, risk to human health and economic loss. However, a number of important agricultural species exhibit a reduction in growth when fertilized with N H 4 + , and increasing the tolerance to N H 4 + may be of importance for the establishment of sustainable agricultural systems. The present study explored the feasibi...

  11. Inactivation of ANAMMOX communities under concurrent operation of anaerobic ammonium oxidation (ANAMMOX) and denitrification

    DEFF Research Database (Denmark)

    Chamchoi, N.; Nitisoravut, S.; Schmidt, Jens Ejbye

    2008-01-01

    A concurrent operation of anaerobic ammonium oxidation (ANAMMOX) and denitrification was investigated in a well known UASB reactor seeding with both ANAMMOX and anaerobic granular sludges. ANAMMOX activity was confirmed by hydroxylamine test and the hybridization of biomass using the gene probes of......–nitrate concentrations in all reactors confirmed the undergone concurrent denitrification which thrives when sufficient organic matter is available. COD concentration over 300 mg l−1 was found to inactivate or eradicate ANAMMOX communities....

  12. Lichens as biomonitors of atmospheric ammonium/ammonia deposition in Portugal

    International Nuclear Information System (INIS)

    The aim of the present work was to evaluate the potentiality of lichens as biomonitors of NH4+/NH3 (ammonium/ammonia) and NO3- (nitrate) atmospheric deposition. For that, we used as a field station a rice plantation which is submitted, once a year, to air spraying fertilization with a mixture of nitrogen sources. Samples of an epiphytic lichen, Ramalina fastigiata, were collected from an ash-tree bordering the rice-plantation by the Sorraia River Valley (Central Portugal). The study started one month before fertilization and sampling was carried out for five months. The concentration of ammonium in the lichen was highly and significantly correlated with the number of days without precipitation before sampling, and had an inverse correlation with fluorescence values. Under these conditions, the amount of NH4+ found in the lichen appears to reflect ammonium/ammonia dry deposition. (author)

  13. Nitrate aerosols today and in 2030: a global simulation including aerosols and tropospheric ozone

    Directory of Open Access Journals (Sweden)

    S. E. Bauer

    2007-10-01

    Full Text Available Nitrate aerosols are expected to become more important in the future atmosphere due to the expected increase in nitrate precursor emissions and the decline of ammonium-sulphate aerosols in wide regions of this planet. The GISS climate model is used in this study, including atmospheric gas- and aerosol phase chemistry to investigate current and future (2030, following the SRES A1B emission scenario atmospheric compositions. A set of sensitivity experiments was carried out to quantify the individual impact of emission- and physical climate change on nitrate aerosol formation. We found that future nitrate aerosol loads depend most strongly on changes that may occur in the ammonia sources. Furthermore, microphysical processes that lead to aerosol mixing play a very important role in sulphate and nitrate aerosol formation. The role of nitrate aerosols as climate change driver is analyzed and set in perspective to other aerosol and ozone forcings under pre-industrial, present day and future conditions. In the near future, year 2030, ammonium nitrate radiative forcing is about −0.14 W/m² and contributes roughly 10% of the net aerosol and ozone forcing. The present day nitrate and pre-industrial nitrate forcings are −0.11 and −0.05 W/m², respectively. The steady increase of nitrate aerosols since industrialization increases its role as a non greenhouse gas forcing agent. However, this impact is still small compared to greenhouse gas forcings, therefore the main role nitrate will play in the future atmosphere is as an air pollutant, with annual mean near surface air concentrations, in the fine particle mode, rising above 3 μg/m³ in China and therefore reaching pollution levels, like sulphate aerosols.

  14. Thermochemical nitrate reduction

    International Nuclear Information System (INIS)

    A series of preliminary experiments was conducted directed at thermochemically converting nitrate to nitrogen and water. Nitrates are a major constituent of the waste stored in the underground tanks on the Hanford Site, and the characteristics and effects of nitrate compounds on stabilization techniques must be considered before permanent disposal operations begin. For the thermochemical reduction experiments, six reducing agents (ammonia, formate, urea, glucose, methane, and hydrogen) were mixed separately with ∼3 wt% NO3- solutions in a buffered aqueous solution at high pH (13); ammonia and formate were also mixed at low pH (4). Reactions were conducted in an aqueous solution in a batch reactor at temperatures of 200 degrees C to 350 degrees C and pressures of 600 to 2800 psig. Both gas and liquid samples were analyzed. The specific components analyzed were nitrate, nitrite, nitrous oxide, nitrogen, and ammonia. Results of experimental runs showed the following order of nitrate reduction of the six reducing agents in basic solution: formate > glucose > urea > hydrogen > ammonia ∼ methane. Airnmonia was more effective under acidic conditions than basic conditions. Formate was also effective under acidic conditions. A more thorough, fundamental study appears warranted to provide additional data on the mechanism of nitrate reduction. Furthermore, an expanded data base and engineering feasibility study could be used to evaluate conversion conditions for promising reducing agents in more detail and identify new reducing agents with improved performance characteristics

  15. Bio-Denitrification of the Nitrate Waste Solution from the Lagoon Sludge in a Batch Fermenter

    International Nuclear Information System (INIS)

    It is a serious task to the decommissioning of the uranium conversion plant that the demolition of the lagoon sludge. The main component of the sludge is ammonium nitrate and that is the very explosive material. Therefore, the bio-denitrification is a attractive process to remove the nitrate. In this work, some process variables was tested such as incubation temperature, nitrate concentration, electron donor, C/N ratio, seeding ratio, and pH with an anaerobic bacteria as Pseudomonas halodenitrificans. The results would be used as basic data to the continuous bio-denitrification process.

  16. Nitrate Remediation of Soil and Groundwater Using Phytoremediation: Transfer of Nitrogen Containing Compounds from the Subsurface to Surface Vegetation

    Science.gov (United States)

    Nelson, Sheldon

    2013-04-01

    Nitrate Remediation of Soil and Groundwater Using Phytoremediation: Transfer of Nitrogen Containing Compounds from the Subsurface to Surface Vegetation Sheldon Nelson Chevron Energy Technology Company 6001 Bollinger Canyon Road San Ramon, California 94583 snne@chevron.com The basic concept of using a plant-based remedial approach (phytoremediation) for nitrogen containing compounds is the incorporation and transformation of the inorganic nitrogen from the soil and/or groundwater (nitrate, ammonium) into plant biomass, thereby removing the constituent from the subsurface. There is a general preference in many plants for the ammonium nitrogen form during the early growth stage, with the uptake and accumulation of nitrate often increasing as the plant matures. The synthesis process refers to the variety of biochemical mechanisms that use ammonium or nitrate compounds to primarily form plant proteins, and to a lesser extent other nitrogen containing organic compounds. The shallow soil at the former warehouse facility test site is impacted primarily by elevated concentrations of nitrate, with a minimal presence of ammonium. Dissolved nitrate (NO3-) is the primary dissolved nitrogen compound in on-site groundwater, historically reaching concentrations of 1000 mg/L. The initial phases of the project consisted of the installation of approximately 1750 trees, planted in 10-foot centers in the areas impacted by nitrate and ammonia in the shallow soil and groundwater. As of the most recent groundwater analytical data, dissolved nitrate reductions of 40% to 96% have been observed in monitor wells located both within, and immediately downgradient of the planted area. In summary, an evaluation of time series groundwater analytical data from the initial planted groves suggests that the trees are an effective means of transfering nitrogen compounds from the subsurface to overlying vegetation. The mechanism of concentration reduction may be the uptake of residual nitrate from the

  17. Tailored Architectures of Ammonium Ionenes

    OpenAIRE

    Tamami, Mana

    2009-01-01

    The synthesis and characterization of a variety of ammonium ionenes from water-soluble coatings to high-performance elastomers are discussed. Water-soluble random copolymer ionenes were synthesized using the Menshutkin reaction from 1,12-dibromododecane, N,N,Nâ ²,Nâ ²-tetramethyl-1,6-hexanediamine, and 1,12-bis(N,N-dimethylamino)dodecane. The absolute molecular weights were determined for the first time using a multiangle laser light scattering detector in aqueous size exclusion chromatograph...

  18. Nitrate and nitrite-mediated transcription antitermination control of nasF (nitrate assimilation) operon expression in Klebsiella pheumoniae M5al.

    Science.gov (United States)

    Lin, J T; Stewart, V

    1996-03-01

    Klebsiella pneumoniae can use nitrate and nitrite as sole nitrogen sources during aerobic growth. Nitrate is converted through nitrite to ammonium by assimilatory nitrate and nitrite reductase, respectively. Enzymes required for nitrate assimilation are encoded by the nasFEDCBA operon of K. pneumoniae; nasF operon expression is subject to both general nitrogen control and pathway-specific nitrate/nitrite induction, mediated by the NtrC and NasR proteins, respectively. Sequence inspection revealed a presumptive sigmaN (sigma54)-dependent promoter as well as two presumptive upstream NtrC protein binding sites. Site-specific mutational and primer extension analyses confirmed the identity of the sigmaN-dependent promoter. Deletions removing the apparent NtrC protein binding sites greatly reduced NtrC-dependent regulation, indicating that these sites are involved in general nitrogen control. However, deletions removing most of the sequence upstream of the promoter had little effect on nitrate/nitrite regulation, suggesting that the nasF leader region is involved in nitrate/nitrite regulation. The 119 nucleotide long transcribed leader region contains an apparent factor-independent transcription terminator. Promoter replacement experiments demonstrated that the leader region is involved in nitrate/nitrite regulation of nasF operon expression. Deletions removing the transcription terminator structure resulted in a nitrate-blind constitutive phenotype, indicating that the transcription terminator structure serves a negative function. Other deletions, removing proximal portions of the leader region, resulted in an uninducible phenotype, indicating that this region serves a positive function. These results indicate that nitrate/nitrite regulation of nasF operon expression is determined by a transcription attenuation mechanism. We hypothesize that in the absence of nitrate or nitrite, the terminator structure abrogates transcription readthrough into the nasF operon. In the

  19. Evaluation on the Nanoscale Zero Valent Iron Based Microbial Denitrification for Nitrate Removal from Groundwater

    Science.gov (United States)

    Peng, Lai; Liu, Yiwen; Gao, Shu-Hong; Chen, Xueming; Xin, Pei; Dai, Xiaohu; Ni, Bing-Jie

    2015-07-01

    Nanoscale zero valent iron (NZVI) based microbial denitrification has been demonstrated to be a promising technology for nitrate removal from groundwater. In this work, a mathematical model is developed to evaluate the performance of this new technology and to provide insights into the chemical and microbial interactions in the system in terms of nitrate reduction, ammonium accumulation and hydrogen turnover. The developed model integrates NZVI-based abiotic reduction of nitrate, NZVI corrosion for hydrogen production and hydrogen-based microbial denitrification and satisfactorily describes all of the nitrate and ammonium dynamics from two systems with highly different conditions. The high NZVI corrosion rate revealed by the model indicates the high reaction rate of NZVI with water due to their large specific surface area and high surface reactivity, leading to an effective microbial nitrate reduction by utilizing the produced hydrogen. The simulation results further suggest a NZVI dosing strategy (3-6 mmol/L in temperature range of 30-40 °C, 6-10 mmol/L in temperature range of 15-30 °C and 10-14 mmol/L in temperature range of 5-15 °C) during groundwater remediation to make sure a low ammonium yield and a high nitrogen removal efficiency.

  20. Nitrate Protects Cucumber Plants Against Fusarium oxysporum by Regulating Citrate Exudation.

    Science.gov (United States)

    Wang, Min; Sun, Yuming; Gu, Zechen; Wang, Ruirui; Sun, Guomei; Zhu, Chen; Guo, Shiwei; Shen, Qirong

    2016-09-01

    Fusarium wilt causes severe yield losses in cash crops. Nitrogen plays a critical role in the management of plant disease; however, the regulating mechanism is poorly understood. Using biochemical, physiological, bioinformatic and transcriptome approaches, we analyzed how nitrogen forms regulate the interactions between cucumber plants and Fusarium oxysporum f. sp. cucumerinum (FOC). Nitrate significantly suppressed Fusarium wilt compared with ammonium in both pot and hydroponic experiments. Fewer FOC colonized the roots and stems under nitrate compared with ammonium supply. Cucumber grown with nitrate accumulated less fusaric acid (FA) after FOC infection and exhibited increased tolerance to chemical FA by decreasing FA absorption and transportation in shoots. A lower citrate concentration was observed in nitrate-grown cucumbers, which was associated with lower MATE (multidrug and toxin compound extrusion) family gene and citrate synthase (CS) gene expression, as well as lower CS activity. Citrate enhanced FOC spore germination and infection, and increased disease incidence and the FOC population in ammonium-treated plants. Our study provides evidence that nitrate protects cucumber plants against F. oxysporum by decreasing root citrate exudation and FOC infection. Citrate exudation is essential for regulating disease development of Fusarium wilt in cucumber plants. PMID:27481896

  1. Nitrate reduction by denitrifying anaerobic methane oxidizing microorganisms can reach a practically useful rate.

    Science.gov (United States)

    Cai, Chen; Hu, Shihu; Guo, Jianhua; Shi, Ying; Xie, Guo-Jun; Yuan, Zhiguo

    2015-12-15

    Methane in biogas has been proposed to be an electron donor to facilitate complete nitrogen removal using denitrifying anaerobic methane oxidizing (DAMO) microorganisms in an anaerobic ammonium oxidation (anammox) reactor, by reducing the nitrate produced. However, the slow growth and the low activity of DAMO microorganisms cast a serious doubt about the practical usefulness of such a process. In this study, a previously established lab-scale membrane biofilm reactor (MBfR), with biofilms consisting of a coculture of DAMO and anammox microorganisms, was operated to answer if the DAMO reactor can achieve a nitrate reduction rate that can potentially be applied for wastewater treatment. Through progressively increasing nitrate and ammonium loading rates to the reactor, a nitrate removal rate of 684 ± 10 mg-N L(-1) d(-1) was achieved after 453 days of operation. This rate is, to our knowledge, by far the highest reported for DAMO reactors, and far exceeds what is predicted to be required for nitrate removal in a sidestream (5.6-135 mg-N L(-1) d(-1)) or mainstream anammox reactor (3.2-124 mg-N L(-1) d(-1)). Mass balance analysis showed that the nitrite produced by nitrate reduction was jointly reduced by anammox bacteria at a rate of 354 ± 3 mg-N L(-1) d(-1), accompanied by an ammonium removal rate of 268 ± 2 mg-N L(-1) d(-1), and DAMO bacteria at a rate of 330 ± 9 mg-N L(-1) d(-1). This study shows that the nitrate reduction rate achieved by the DAMO process can be high enough for removing nitrate produced by anammox process, which would enable complete nitrogen removal from wastewater. PMID:26414889

  2. Ammonium assmilation in spruce ectomycorrhizas

    Energy Technology Data Exchange (ETDEWEB)

    Chalot, M.; Brun, A.; Botton, B. (Univ. of nancy, Vandoeuvre-les-Nancy (France)); Stewart, G. (University College, London (England))

    1990-05-01

    Assimilation of labelled NH{sub 4}{sup +} into amino acids has been followed in ectomycorrhizal roots of spruce. Over an 18 h period of NH{sub 4}{sup +} feeding, Gln, Glu and Ala became the most abundant amino acids. Gln was also the most highly labelled amino acid during the experiment, followed by Glu and Ala. This result indicates that Gln synthesis is an important ammonium utilization reaction in spruce mycorrhizas. Addition of MSX to NH{sub 4}{sup +} fed mycorrhizas caused an inhibition of Gln accumulation with a corresponding increase in Glu, Ala and Asn levels. The supply of MSX induced a sharp diminution of {sup 15}N enrichment in both amino and amido groups of glutamine. In contrast, the {sup 15}N incorporation into Glu and derivatives (Ala and Asp) remained very high. This study demonstrates that the fungal glutamate dehydrogenase is quite operative in spruce ectomycorrhizas since it is able to sustain ammonium assimilation when glutamine synthetase is inhibited.

  3. 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.

  4. Rapid And Accurate Technique For Measuring N-15 Of Nitrate Method Development, Calibration And Validation

    International Nuclear Information System (INIS)

    A precise and simplified procedure for measuring nitrogen-15 of nitrate in water with moderate ionic strength and moderate to high organic loads is presented. The modified analytical train consists of two main steps: (a) extraction and purification of nitrate from liquid matrix and (b) pyrolysis of purified potassium nitrate. The presented method was evaluated with simulated solutions containing constant amounts of inter-laboratory nitrate standard salt (KNO3 , δ15N = -4.34 ± 0.32 % AirN2) and potentially interfering anions (SO42-, Cl- and HCO3-) as well as dissolved organic carbon (DOC) load. Dowex 1X8 anion exchange resin proved to be a suitable mean and provide accurate and reproducible δ15N values (SD: ± 0.48%).It tolerates high concentrations of chloride and sulfate ions for samples of small volumes (100 ml) of about four folds of the amounts enough to fully saturate the resin column. Rapid, accurate, precise, low-priced and less labour intensive activated graphite based offline pyrolysis technique for measuring N-15 content of nitrate has been developed and implemented. This involves combusting nitrate salt with activated graphite at 550oC for 30 minutes. Dramatic reduction in processing times needed for the analysis of N-15 of nitrate at natural abundance level was achieved. Performance characteristics of the modified analytical cascade showed that 1 to 2 hrs/sample/set of 5 samples processing time is required. The pyrolysis step of the developed method was validated using internationally distributed nitrate stable isotope reference materials. N-15 content of some selected nitrate salts, namely calcium nitrate, sodium nitrate, potassium nitrate and ammonium nitrate fertilizer, was measured using the modified technique, vacuum distillation method, modified ammonia diffusion method, microbial denitrifier method and EA-CF IRMS method at two different laboratories in Egypt and Germany. The results proved the validity and applicability of the modified

  5. Hydrogen anode for nitrate waste destruction. Revision 2

    International Nuclear Information System (INIS)

    Large quantities of radioactive and hazardous wastes have been generated from nuclear materials production during the past fifty years. Processes are under evaluation to separate the high level radioactive species from the waste and store them permanently in the form of durable solids. The schemes proposed will separate the high level radioactive components, cesium-137 and strontium-90, into a small volume for incorporation into a glass wasteform. The remaining low-level radioactive waste contain species such as nitrites and nitrates that are capable of contaminating ground water. Electrochemical destruction of the nitrate and nitrite before permanent storage has been proposed. Not only will the electrochemical processing destroy these species, the volume of the waste could also be reduced. The use of a hydrogen gas-fed anode and an acid anolyte in an electrochemical cell used to destroy nitrate was demonstrated. A mixed Na2SO4/H2SO4 anolyte was shown to favor the nitrate cell performance, and the generation of a higher hydroxide ion concentration in the catholyte. The suggested scheme is an apparent method of sodium sulfate disposal and a possible means through which ammonia (to ammonium sulfate, fertilizer) and hydrogen gas could be recycled through the anode side of the reactor. This could result in a substantial savings in the operation of a nitrate destruction cell

  6. Dissimilatory nitrate reduction by Aspergillus terreus isolated from the seasonal oxygen minimum zone in the Arabian Sea

    DEFF Research Database (Denmark)

    Stief, Peter; Fuchs-Ocklenburg, Silvia; Kamp, Anja; Manohar, Cathrine Sumathi; Houbraken, Jos; Boekhout, Teun; De Beer, Dirk; Stoeck, Thorsten

    2014-01-01

    Background: A wealth of microbial eukaryotes is adapted to life in oxygen-deficient marine environments. Evidence is accumulating that some of these eukaryotes survive anoxia by employing dissimilatory nitrate reduction, a strategy that otherwise is widespread in prokaryotes. Here, we report on the...... anaerobic nitrate metabolism of the fungus Aspergillus terreus (isolate An-4) that was obtained from sediment in the seasonal oxygen minimum zone in the Arabian Sea, a globally important site of oceanic nitrogen loss and nitrous oxide emission. Results: Axenic incubations of An-4 in the presence and absence...... dissimilatory nitrate reduction when oxygen is absent. In the currently spreading oxygen-deficient zones in the ocean, an as yet unexplored diversity of fungi may recycle nitrate to ammonium and nitrite, the substrates of the major nitrogen loss process anaerobic ammonium oxidation, and the potent greenhouse...

  7. Denitrification rate determined by nitrate disapperance is higher than determined by nitrous oxide production with acetylene blockage

    DEFF Research Database (Denmark)

    Yu, Kewei; Struwe, Sten; Kjøller, Annelise;

    2008-01-01

    A mixed beech and spruce forest soil was incubated under potential denitrification assay (PDA) condition with 10% acetylene (C2H2) in the headspace of soil slurry bottles. Nitrous oxide (N2O) concentration in the headspace, as well as nitrate, nitrite and ammonium concentrations in the soil...... different treatments. Commonly applied PDA measurement likely underestimates the nitrate removal capacity of a system. Incubation time and organic matter/nitrate ratio are the most critical factors to consider using C2H2 inhibition technique to quantify denitrification. By comparing the treatments with and...... slurries were monitored during the incubation. Results show that nitrate disappearance rate was higher than N2O production rate with C2H2 blockage during the incubation. Sum of nitrate, nitrite, and N2O with C2H2 blockage could not recover the original soil nitrate content, showing an N imbalance in such a...

  8. Determination of nitrate and nitrite in dairy samples by sequential injection using an in-line cadmium-reducing column

    OpenAIRE

    Lima, M.J. Reis; Fernandes, Sílvia M.V.; Rangel, António O.S.S.

    2006-01-01

    A sequential injection analysis (SIA) system for the spectrophotometric determination of nitrate in dairy samples was developed. A test portion was aspirated into a carrier solution containing ethylendiaminetetracetic acid (EDTA) and ammonium buffer, which flowed into a copperized cadmium reduction column installed in-line for the determination of the nitrate plus nitrite contents of samples. For the nitrite determination, another test portion of sample was aspirated and directly sen...

  9. Reclassification of the sulfate- and nitrate-reducing bacterium Desulfovibrio vulgaris subsp oxamicus as Desulfovibrio oxamicus sp nov., comb. nov

    OpenAIRE

    Lopez Cortes, A.; Fardeau, Marie-Laure; Fauque, Guy; Joulian, C.; Ollivier, Bernard

    2006-01-01

    Desulfovibrio vulgaris subsp. oxamicus (type strain, DSM 1925(T)) was found to use nitrate as a terminal electron acceptor, the latter being reduced to ammonium. Phylogenetic studies indicated that strain DSM 1925 T was distantly related to the type strain of Desulfovibrio vulgaris (95(.)4% similarity of the small-subunit rRNA gene) and had as its closest phylogenetic relatives two other nitrate- and sulfate-reducing bacteria, namely Desulfovibrio termitidis (99(.)4% similarity) and Desulfovi...

  10. Nitrates and nitrites intoxications’ management

    OpenAIRE

    Alexandra Trif

    2007-01-01

    The study pointed out the major sources for clinical and subclinical intoxications with nitrates/nitrites (drinking water and nitrates containing fertilizers), circumstances that determine fertilizers to became sources of intoxication (excessive fertilization/consecutive high level of nitrates in fodders, free access of animals to the fertilizers, administration into the diet instead of natrium chloride), factors that determine high nitrates accumulation in fodders despite optimal fertilizati...

  11. Thermal analysis studies of ammonium uranyl carbonate

    International Nuclear Information System (INIS)

    The simultaneous thermogravimetry and differential thermal analysis of the ammonium uranyl carbonate powder were performed with heat balance in the following atmosphers: Air, Ar and Ar-8%H2. The thermogravimetry and differential thermal analysis curves of the ammonium uranyl carbonate powder obtained from different source were reported and discussed

  12. An electrokinetic/Fe0 permeable reactive barrier system for the treatment of nitrate-contaminated subsurface soils.

    Science.gov (United States)

    Suzuki, Tasuma; Oyama, Yukinori; Moribe, Mai; Niinae, Masakazu

    2012-03-01

    Effective nitrate removal by Fe(0) permeable reactive barriers (Fe(0) PRB) has been recognized as a challenging task because the iron corrosion product foamed on Fe(0) hinders effective electron transfer from Fe(0) to surface-bound nitrate. The objectives of this study were (i) to demonstrate the effectiveness of an electrokinetic/Fe(0) PRB system for remediating nitrate-contaminated low permeability soils using a bench-scale system and (ii) to deepen the understanding of the behavior and fate of nitrate in the system. Bench-scale laboratory experiments were designed to investigate the influence of the Fe(0) content in the permeable reactive barrier, the pH in the anode well, and the applied voltage on remediation efficiency. The experimental results showed that the major reaction product of nitrate reduction by Fe(0) was ammonium and that nitrate reduction efficiency was significantly influenced by the variables investigated in this study. Nitrate reduction efficiency was enhanced by either increasing the Fe(0) content in the Fe(0) reactive barrier or decreasing the initial anode pH. However, nitrate reduction efficiency was reduced by increasing the applied voltage from 10 V to 40 V due to the insufficient reaction time during nitrate migration through the Fe(0) PRB. For all experimental conditions, nearly all nitrate nitrogen was recovered in either anode or cathode wells as nitrate or ammonium within 100 h, demonstrating the effectiveness of the system for remediating nitrate-contaminated subsurface soils. PMID:22153957

  13. Evolution of Electrogenic Ammonium Transporters (AMTs).

    Science.gov (United States)

    McDonald, Tami R; Ward, John M

    2016-01-01

    The ammonium transporter gene family consists of three main clades, AMT, MEP, and Rh. The evolutionary history of the AMT/MEP/Rh gene family is characterized by multiple horizontal gene transfer events, gene family expansion and contraction, and gene loss; thus the gene tree for this family of transporters is unlike the organismal tree. The genomes of angiosperms contain genes for both electrogenic and electroneutral ammonium transporters, but it is not clear how far back in the land plant lineage electrogenic ammonium transporters occur. Here, we place Marchantia polymorpha ammonium transporters in the AMT/MEP/Rh phylogeny and we show that AMTs from the liverwort M. polymorpha are electrogenic. This information suggests that electrogenic ammonium transport evolved at least as early as the divergence of bryophytes in the land plant lineage. PMID:27066024

  14. Modeled aerosol nitrate formation pathways during wintertime in the Great Lakes region of North America

    Science.gov (United States)

    Kim, Yoo Jung; Spak, Scott N.; Carmichael, Gregory R.; Riemer, Nicole; Stanier, Charles O.

    2014-11-01

    Episodic wintertime particle pollution by ammonium nitrate is an important air quality concern across the Midwest U.S. Understanding and accurately forecasting PM2.5 episodes are complicated by multiple pathways for aerosol nitrate formation, each with uncertain rate parameters. Here, the Community Multiscale Air Quality model (CMAQ) simulated regional atmospheric nitrate budgets during the 2009 LADCO Winter Nitrate Study, using integrated process rate (IPR) and integrated reaction rate (IRR) tools to quantify relevant processes. Total nitrate production contributing to PM2.5 episodes is a regional phenomenon, with peak production over the Ohio River Valley and southern Great Lakes. Total nitrate production in the lower troposphere is attributed to three pathways, with 57% from heterogeneous conversion of N2O5, 28% from the reaction of OH and NO2, and 15% from homogeneous conversion of N2O5. TNO3 formation rates varied day-to-day and on synoptic timescales. Rate-limited production does not follow urban-rural gradients and NOx emissions due, to counterbalancing of urban enhancement in daytime HNO3 production with nocturnal reductions. Concentrations of HNO3 and N2O5 and nighttime TNO3 formation rates have maxima aloft (100-500 m), leading to net total nitrate vertical flux during episodes, with substantial vertical gradients in nitrate partitioning. Uncertainties in all three pathways are relevant to wintertime aerosol modeling and highlight the importance of interacting transport and chemistry processes during ammonium nitrate episodes, as well as the need for additional constraint on the system through field and laboratory experiments.

  15. Photocatalytic reduction of nitrate using titanium dioxide for regeneration of ion exchange brine.

    Science.gov (United States)

    Yang, Ting; Doudrick, Kyle; Westerhoff, Paul

    2013-03-01

    Nitrate is often removed from groundwater by ion exchange (IX) before its use as drinking water. Accumulation of nitrate in IX brine reduces the efficiency of IX regeneration and the useful life of the regeneration brine. For the first time, we present a strategy to photocatalytically reduce nitrate in IX brine, thereby extending the use of the brine. Titanium dioxide (Evonik P90), acting as photocatalyst, reduced nitrate effectively in both synthetic brines and sulfate-removed IX brine when formic acid (FA) was used as the hole scavenger (i.e., electron donor) and the initial FA to nitrate molar ratio (IFNR) was 5.6. Increasing the NaCl level in the synthetic brine slowed the nitrate reduction rate without affecting by-product selectivity of ammonium and gaseous N species (e.g., N(2), N(2)O). In a non-modified IX brine, nitrate removal was greatly inhibited owing to the presence of sulfate, which competed with nitrate for active surface sites on P90 and induced aggregation of P90 nanoparticles. After removing sulfate through barium sulfate precipitation, nitrate was effectively reduced; approximately 3.6 × 10(24) photons were required to reduce each mole of nitrate to 83% N Gases and 17% NH(4)(+). To make optimum use of FA and control the residual FA level in treated brine, the IFNR was varied. High IFNRs (e.g., 4, 5.6) were found to be more efficient for nitrate reduction but left higher residual FA in brine. IX column tests were performed to investigate the impact of residual FA for brine reuse. The residual FA in the brine did not significantly affect the nitrate removal capacity of IX resins, and formate contamination of treated water could be eliminated by rinsing with one bed volume of fresh brine. PMID:23276425

  16. 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.

  17. Biological nitrogen removal in one step by nitritation and anaerobic oxidation of ammonia in biofilms; Einstufige biologische Stickstoffelimination durch Nitritation und anaerobe Ammonium-Oxidation im Biofilm

    Energy Technology Data Exchange (ETDEWEB)

    Helmer, C.; Tromm, C.; Hippen, A.; Rosenwinkel, K.H.; Seyfried, C.F.; Kunst, S. [Hannover Univ. (Germany). Inst. fuer Siedlungswasserwirtschaft und Abfalltechnik

    1999-07-01

    For biological treatment of high nitrogenous wastewaters with low C/N ratio autotrophic microorganisms which are able to convert ammonium directly into nitrogen gas are especially interesting. It is exceptionally difficult to verify their presence and importance in mixed populations of full scale wastewater treatment plants. So it could not be clarified finally up to now which basic microbial reactions lead to single stage complete nitrogen removal, here called deammonification, in the nitrification step (biological contactor) of the leachate treatment plant in Mechernich. It succeeded meanwhile to establish the process of deammonification in a continuous flow moving-bed pilot plant. In batch experiments which biomass-covered carriers nitrogen conversions could become investigated at the intact biofilm for the first time. Two autotrophic nitrogen conversion reactions could be proved in the biofilm depending on dissolved oxygen (DO) concentration: A nitritation under aerobic conditions and an anaerobic ammonium oxidation. For the anaerobic ammonium oxidation nitrite was used as electron acceptor with ammonium as electron donor. N{sub 2} was the end product of the reaction. The ratio of ammonium conversion to nitrite conversion was 1:1,37, which was described in the same range for the ANAMMOX-process (1:1,31{+-}0,06). Nitrate could not be used as electron acceptor. Nitrite had to be added to the experiment to obtain oxygen independent oxidation of ammonium. The parts of nitritation and anaerobic ammonium conversion in nitrogen conversion could be controlled by the DO concentration. At a DO concentration of 0.7 mg/l both processes were balanced, so that a direct almost complete elimination of ammonium was possible without any dosage of nitrite. The added ammonium was partially oxidised to nitrite and partially oxidised anaerobically. The aerobic ammonium oxidation to nitrite in the outer oxygen supplied biofilm layers produced the reactant for the anaerobic ammonium

  18. Determination of fluoride with thorium nitrate by catalytic titration

    International Nuclear Information System (INIS)

    Amperometry, constant-current potentiometry and spectrophotometry were used to follow the course of catalytic titrations of fluoride and silicofluoride with thorium nitrate. The hydrogen peroxide-iodide system was used as the indicator reaction. Titrations were performed in 50% ethanolic acetate buffer, pH 3.6. Amounts of 3.70 to 6.85 mg of ammonium fluoride, 5.53 to 10.79 mg of potassium fluoride and 4.34 to 8.41 mg of sodium silicofluoride were determined with a maximum average deviation of 0.9%. The results obtained are in good agreement with those of comparable methods. (author)

  19. Nitrate in drinking water

    DEFF Research Database (Denmark)

    Schullehner, Jörg; Hansen, Birgitte; Sigsgaard, Torben

    Annual nationwide exposure maps for nitrate in drinking water in Denmark from the 1970s until today will be presented based on the findings in Schullehner & Hansen (2014) and additional work on addressing the issue of private well users and estimating missing data. Drinking water supply in Denmark...... is highly decentralized and fully relying on simple treated groundwater. At the same time, Denmark has an intensive agriculture, making groundwater resources prone to nitrate pollution. Drinking water quality data covering the entire country for over 35 years are registered in the public database Jupiter....... In order to create annual maps of drinking water quality, these data had to be linked to 2,852 water supply areas, which were for the first time digitized, collected in one dataset and connected to the Jupiter database. Analyses of the drinking water quality maps showed that public water supplies...

  20. Nitrates and nitrites intoxications’ management

    Directory of Open Access Journals (Sweden)

    Alexandra Trif

    2007-12-01

    Full Text Available The study pointed out the major sources for clinical and subclinical intoxications with nitrates/nitrites (drinking water and nitrates containing fertilizers, circumstances that determine fertilizers to became sources of intoxication (excessive fertilization/consecutive high level of nitrates in fodders, free access of animals to the fertilizers, administration into the diet instead of natrium chloride, factors that determine high nitrates accumulation in fodders despite optimal fertilization (factors related to the plants, soil, clime, harvest methods, storage, agrotechnical measures, nitrates/nitrites toxicity (over 45 ppm nitrates in drinking water, over 0.5 g nitrate/100 g D.M fodder/diet, the factors that influence nitrates/nitrites toxicity ( species, age, rate of feeding, diet balance especially energetically, pathological effects and symptoms (irritation and congestions on digestive tract, resulting diarrhoea, transformation of hemoglobin into methemoglobin determining severe respiratory insufficiency, vascular collapse, low blood pressure inthe acute nitrates intoxication; hypotiroidism, hypovitaminosis A, reproductive disturbances(abortion, low rate of fertility, dead born offspring, diarrhoea and/or respiratory insufficiency in new born e.g. calves, immunosuppression, decrease of milk production in chronic intoxication. There were presented some suggestions concerning management practices to limit nitrate intoxication (analyze of nitrates/nitrites in water and fodders, good management of the situation of risk ,e .g. dilution of the diet with low nitrate content fodders, feeding with balanced diet in energy, protein, minerals and vitamins, accommodation to high nitrate level diet, avoid grazing one week after a frost period, avoid feeding chop green fodders stored a couple of days, monitoring of health status of animals fed with fodders containing nitrates at risk level, a.o..

  1. Structures of genes nasA and nasB, encoding assimilatory nitrate and nitrite reductases in Klebsiella pneumoniae M5al.

    OpenAIRE

    Lin, J. T.; Goldman, B. S.; Stewart, V

    1993-01-01

    Klebsiella pneumoniae can use nitrate and nitrite as sole nitrogen sources during aerobic growth. Assimilatory nitrate and nitrite reductases convert nitrate through nitrite to ammonium. We report here the molecular cloning of the nasA and nasB genes, which encode assimilatory nitrate and nitrite reductase, respectively. These genes are tightly linked and probably form a nasBA operon. In vivo protein expression and DNA sequence analysis revealed that the nasA and nasB genes encode 92- and 104...

  2. Coupling between anammox and autotrophic denitrification for simultaneous removal of ammonium and sulfide by enriched marine sediments.

    Science.gov (United States)

    Rios-Del Toro, E Emilia; Cervantes, Francisco J

    2016-06-01

    In the present study, the capacity of enrichments derived from marine sediments collected from different sites of the Mexican littoral to perform anaerobic ammonium oxidation (anammox) coupled to sulfide-dependent denitrification for simultaneous removal of ammonium and sulfide linked to nitrite reduction was evaluated. Sulfide-dependent denitrification out-competed anammox during the simultaneous oxidation of sulfide and ammonium. Significant accumulation of elemental sulfur (ca. 14-30 % of added sulfide) occurred during the coupling between the two respiratory processes, while ammonium was partly oxidized (31-47 %) due to nitrite limitation imposed in sediment incubations. Nevertheless, mass balances revealed up to 38 % more oxidation of the electron donors available (ammonium and sulfide) than that expected from stoichiometry. Recycling of nitrite, from nitrate produced through anammox, is proposed to contribute to extra oxidation of sulfide, while additional ammonium oxidation is suggested by sulfate-reducing anammox (SR-anammox). The complex interaction between nitrogenous and sulfurous compounds occurring through the concomitant presence of autotrophic denitrification, conventional anammox and SR-anammox may significantly drive the nitrogen and sulfur fluxes in marine environments. PMID:26994921

  3. Ammonium-dependent regulation of aerobic methane-consuming bacteria in landfill cover soil by leachate irrigation

    Institute of Scientific and Technical Information of China (English)

    Fan Lü; Pinjing He; Min Guo; Na Yang; Liming Shao

    2012-01-01

    The impacts of landfill leachate irrigation on methane oxidation activities and methane-consuming bacteria populations were studied by incubation of landfill cover soils with leachate and (NH4)2SO4 solution at different ammonium concentrations.The community structures and abundances of methane-oxidizing bacteria (MOB) and ammonia-oxidizing bacteria (AOB) were examined by PCRDGGE and real-time PCR.Compared with the pure (NH4)2SO4 solution,leachate addition was found to have a positive effect on methane oxidation activity.In terms of the irrigation amount,ammonium in leachate was responsible for the actual inhibition of leachate.The extent of inhibitory effect mainly depended on its ammonium concentration.The suppression of the predominant methaneconsuming bacteria,type Ⅰ MOB,was responsible for the decreased methane oxidation activity by ammonium inhibition.Methaneconsuming bacteria responded diversely in abundance to ammonium.The abundance of type Ⅰ MOB decreased by fivefold; type Ⅱ MOB showed stimulation response of fivefold magnification upon the first addition but lessened to be lower than the original level after the second addition; the amount of AOB was stimulated to increase for 20-30 times gradually.Accumulated nitrate from nitrification strengthened the ammonium inhibition on type Ⅰ and type Ⅱ MOB,as a result,repetitive irrigation was unfavorable for methane oxidation.

  4. Enhanced removal of nitrate from water using nZVI@MWCNTs composite: synthesis, kinetics and mechanism of reduction.

    Science.gov (United States)

    Babaei, Ali Akbar; Azari, Ali; Kalantary, Roshanak Rezaei; Kakavandi, Babak

    2015-01-01

    Herein, multi-wall carbon nanotubes (MWCNTs) were used as the carrier of nano-zero valent iron (nZVI) particles to fabricate a composite known as nZVI@MWCNTs. The composite was then characterized and applied in the nitrate removal process in a batch system under anoxic conditions. The influential parameters such as pH, various concentrations of nitrate and composite were investigated within 240 min of the reaction. The mechanism, kinetics and end-products of nitrate reduction were also evaluated. Results revealed that the removal nitrate percentage for nZVI@MWCNTs composite was higher than that of nZVI and MWCNTs alone. Experimental data from nitrate reduction were fitted to the Langmuir-Hinshelwood kinetic model. The values of observed rate constant (kobs) decreased with increasing the initial concentration of nitrate. Our experiments proved that the nitrate removal efficiency was favorable once both high amounts of nZVI@MWCNTs and low concentrations of nitrate were applied. The predominant end-products of the nitrate reduction were ammonium (84%) and nitrogen gas (15%). Our findings also revealed that ZVI@MWCNTs is potentially a good composite for removal/reduction of nitrate from aqueous solutions. PMID:26606093

  5. Both free indole-3-acetic acid and the photosynthetic performance are important players in the response of Medicago truncatula to urea and ammonium nutrition under axenic conditions

    Directory of Open Access Journals (Sweden)

    RAQUEL eEsteban

    2016-02-01

    Full Text Available We aimed to identify the early stress response and plant performance of Medicago truncatula growing in axenic medium with ammonium or urea as the sole source of nitrogen with respect to nitrate based nutrition through biomass measurements, auxin contents analyses, root system architecture response analyses, and physiological determinations. Both ammonium and ureic nutrition severely affected the root system architecture, resulting in changes in the main elongation rate, lateral root development and insert position from the base. The auxin content decreased in both urea- and ammonium- treated roots; however, only the ammonium- treated plants were affected at the shoot level. The analysis of chlorophyll a fluorescence transients showed that ammonium affected photosystem II, but urea did not impair photosynthetic activity. Superoxide dismutase isoenzymes in the plastids were moderately affected by urea and ammonium in the roots. Overall, our results showed that low N doses from different sources had no remarkable effects on M. truncatula, with the exception of the differential phenotypic root response. High dose of both ammonium and urea caused great changes at plant length, auxin content and physiological determinations. The interesting correlations found between the shoot auxin pool, the plant length, and the parameter performance index, obtained from the chlorophyll a fluorescence rise kinetics measurements, indicated that both IAA pool and performance index are an important part of the response of M. truncatula under ammonium or urea as a sole N source.

  6. Both Free Indole-3-Acetic Acid and Photosynthetic Performance are Important Players in the Response of Medicago truncatula to Urea and Ammonium Nutrition Under Axenic Conditions.

    Science.gov (United States)

    Esteban, Raquel; Royo, Beatriz; Urarte, Estibaliz; Zamarreño, Ángel M; Garcia-Mina, José M; Moran, Jose F

    2016-01-01

    We aimed to identify the early stress response and plant performance of Medicago truncatula growing in axenic medium with ammonium or urea as the sole source of nitrogen, with respect to nitrate-based nutrition. Biomass measurements, auxin content analyses, root system architecture (RSA) response analyses, and physiological parameters were determined. Both ammonium and ureic nutrition severely affected the RSA, resulting in changes in the main elongation rate, lateral root development, and insert position from the root base. The auxin content decreased in both urea- and ammonium-treated roots; however, only the ammonium-treated plants were affected at the shoot level. The analysis of chlorophyll a fluorescence transients showed that ammonium affected photosystem II, but urea did not impair photosynthetic activity. Superoxide dismutase isoenzymes in the plastids were moderately affected by urea and ammonium in the roots. Overall, our results showed that low N doses from different sources had no remarkable effects on M. truncatula, with the exception of the differential phenotypic root response. High doses of both ammonium and urea caused great changes in plant length, auxin contents and physiological measurements. Interesting correlations were found between the shoot auxin pool and both plant length and the "performance index" parameter, which is obtained from measurements of the kinetics of chlorophyll a fluorescence. Taken together, these data demonstrate that both the indole-3-acetic acid pool and performance index are important components of the response of M. truncatula under ammonium or urea as the sole N source. PMID:26909089

  7. Nitrate reduction to nitrite, nitric oxide and ammonia by gut bacteria under physiological conditions.

    Directory of Open Access Journals (Sweden)

    Mauro Tiso

    Full Text Available The biological nitrogen cycle involves step-wise reduction of nitrogen oxides to ammonium salts and oxidation of ammonia back to nitrites and nitrates by plants and bacteria. Neither process has been thought to have relevance to mammalian physiology; however in recent years the salivary bacterial reduction of nitrate to nitrite has been recognized as an important metabolic conversion in humans. Several enteric bacteria have also shown the ability of catalytic reduction of nitrate to ammonia via nitrite during dissimilatory respiration; however, the importance of this pathway in bacterial species colonizing the human intestine has been little studied. We measured nitrite, nitric oxide (NO and ammonia formation in cultures of Escherichia coli, Lactobacillus and Bifidobacterium species grown at different sodium nitrate concentrations and oxygen levels. We found that the presence of 5 mM nitrate provided a growth benefit and induced both nitrite and ammonia generation in E.coli and L.plantarum bacteria grown at oxygen concentrations compatible with the content in the gastrointestinal tract. Nitrite and ammonia accumulated in the growth medium when at least 2.5 mM nitrate was present. Time-course curves suggest that nitrate is first converted to nitrite and subsequently to ammonia. Strains of L.rhamnosus, L.acidophilus and B.longum infantis grown with nitrate produced minor changes in nitrite or ammonia levels in the cultures. However, when supplied with exogenous nitrite, NO gas was readily produced independently of added nitrate. Bacterial production of lactic acid causes medium acidification that in turn generates NO by non-enzymatic nitrite reduction. In contrast, nitrite was converted to NO by E.coli cultures even at neutral pH. We suggest that the bacterial nitrate reduction to ammonia, as well as the related NO formation in the gut, could be an important aspect of the overall mammalian nitrate/nitrite/NO metabolism and is yet another way in

  8. Leaching of lead by ammonium salts and EDTA from Salvinia minima biomass produced during aquatic phytoremediation.

    Science.gov (United States)

    Núñez-López, Roberto Aurelio; Meas, Yunny; Gama, Silvia Citlalli; Borges, Raúl Ortega; Olguín, Eugenia J

    2008-06-15

    Plant biomass harvested after heavy-metal phytoremediation must be considered as a hazardous waste that should be contained or treated appropriately before disposal or reuse. As a potential method to detoxify the biomass and to convert this material to a suitable fertilizer or mulch, leaching of lead (Pb) from Salvinia minima biomass was studied by testing water, several aqueous ammonium salts, and EDTA solution as lead extractants. The research was carried out in two phases: (i) a leaching study to determine the lead-extraction efficiency of the different leachants, and (ii) a thermodynamic analysis to identify the likely reactions and stable Pb(II) species formed in the leaching systems of the most efficient leachants. Experimentally, lead concentrations measured in leached biomass and in leachates were significantly different among the various leachants. It was determined that the extraction strength of the leachants followed the order: EDTA>ammonium oxalate>water approximately ammonium nitrate>ammonium acetate, achieving Pb extraction efficiencies of 99%, 70%, 7.2%, 6.9% and 1.3%, respectively, in single-stage extractions. The thermodynamic study indicated that the dominant species produced by the leaching process should be the soluble species PbEDTA2- for EDTA system, and the insoluble Pb(COO)2S precipitate for the oxalate system. PMID:18078711

  9. Leaching of lead by ammonium salts and EDTA from Salvinia minima biomass produced during aquatic phytoremediation

    International Nuclear Information System (INIS)

    Plant biomass harvested after heavy-metal phytoremediation must be considered as a hazardous waste that should be contained or treated appropriately before disposal or reuse. As a potential method to detoxify the biomass and to convert this material to a suitable fertilizer or mulch, leaching of lead (Pb) from Salvinia minima biomass was studied by testing water, several aqueous ammonium salts, and EDTA solution as lead extractants. The research was carried out in two phases: (i) a leaching study to determine the lead-extraction efficiency of the different leachants, and (ii) a thermodynamic analysis to identify the likely reactions and stable Pb(II) species formed in the leaching systems of the most efficient leachants. Experimentally, lead concentrations measured in leached biomass and in leachates were significantly different among the various leachants. It was determined that the extraction strength of the leachants followed the order: EDTA > ammonium oxalate > water ∼ ammonium nitrate > ammonium acetate, achieving Pb extraction efficiencies of 99%, 70%, 7.2%, 6.9% and 1.3%, respectively, in single-stage extractions. The thermodynamic study indicated that the dominant species produced by the leaching process should be the soluble species PbEDTA2- for EDTA system, and the insoluble Pb(COO)2S precipitate for the oxalate system

  10. An overview on the synthetic routes and properties of ammonium dinitramide (ADN) and other dinitramide salts

    Energy Technology Data Exchange (ETDEWEB)

    Venkatachalam, Subbiah; Santhosh, Gopalakrishnan; Ninan Ninan, Kovoor [Propellants and Special Chemicals Group, Vikram Sarabhai Space Centre, Trivandrum 695 022 (India)

    2004-06-01

    In recent years, there has been a considerable interest in the development of novel type of high performance propellants for use in solid rocket motors. Ammonium salt of dinitramidic acid NH{sub 4}N(NO{sub 2}){sub 2} (ADN) has attracted wide interest as a potentially useful energetic oxidizer for rocket propellants because of its clean and environment-friendly exhaust products during burning. ADN contains one N-(NO{sub 2}){sub 2} group and its synthesis requires new type of N-nitration. The present paper reviews the general synthetic methods used for the synthesis of inorganic, organic and metal dinitramide salts and their properties, with a special emphasis on ammonium dinitramide. The salient features with reference to the extent of conversion and ease of separation of the products of the various synthetic methodologies are also addressed. (Abstract Copyright [2004], Wiley Periodicals, Inc.)

  11. Study and characterization of ammonium diuranate and uranium trioxide by thermogravimetry and differential scanning calorimetry

    International Nuclear Information System (INIS)

    Thermogravimetry (TG), Differential Thermogravimetry (DTG) and Differential Scanning Calorimetry (DSC) were used to characterize the thermal behavior of ammonium diuranate (ADU) and uranium trioxide (UO3) produced at IPEN'S Chemical Enginnering Department. Compounds characterization was done using the molar ratios among the compounds and the oxides resulting from thermal decomposition. The TG and DTG curves registered for each sample were used for the determination of the following temperatures: - temperature of water evolution (free and crystallized water); - ammonia evolution and oxidation temperature; - ocluded ammonium nitrate decomposition temperature and - oxygen release temperature. The intermediate phases and their thermal stabilities were also identified by TG and DTG and confirmed by DSC curves, DSC curves showed also the exothermic and endothermic behavior of the processes involved. Finally, the great amount of data collected in this study can be handed as a guide by the professionals responsible for the operation of ADU,UO3 and UF4 pilot plants. (Author)

  12. Nitrate biosensors and biological methods for nitrate determination.

    Science.gov (United States)

    Sohail, Manzar; Adeloju, Samuel B

    2016-06-01

    The inorganic nitrate (NO3‾) anion is present under a variety of both natural and artificial environmental conditions. Nitrate is ubiquitous within the environment, food, industrial and physiological systems and is mostly present as hydrated anion of a corresponding dissolved salt. Due to the significant environmental and toxicological effects of nitrate, its determination and monitoring in environmental and industrial waters are often necessary. A wide range of analytical techniques are available for nitrate determination in various sample matrices. This review discusses biosensors available for nitrate determination using the enzyme nitrate reductase (NaR). We conclude that nitrate determination using biosensors is an excellent non-toxic alternative to all other available analytical methods. Over the last fifteen years biosensing technology for nitrate analysis has progressed very well, however, there is a need to expedite the development of nitrate biosensors as a suitable alternative to non-enzymatic techniques through the use of different polymers, nanostructures, mediators and strategies to overcome oxygen interference. PMID:27130094

  13. Electrochemically and bioelectrochemically induced ammonium recovery.

    Science.gov (United States)

    Gildemyn, Sylvia; Luther, Amanda K; Andersen, Stephen J; Desloover, Joachim; Rabaey, Korneel

    2015-01-01

    Streams such as urine and manure can contain high levels of ammonium, which could be recovered for reuse in agriculture or chemistry. The extraction of ammonium from an ammonium-rich stream is demonstrated using an electrochemical and a bioelectrochemical system. Both systems are controlled by a potentiostat to either fix the current (for the electrochemical cell) or fix the potential of the working electrode (for the bioelectrochemical cell). In the bioelectrochemical cell, electroactive bacteria catalyze the anodic reaction, whereas in the electrochemical cell the potentiostat applies a higher voltage to produce a current. The current and consequent restoration of the charge balance across the cell allow the transport of cations, such as ammonium, across a cation exchange membrane from the anolyte to the catholyte. The high pH of the catholyte leads to formation of ammonia, which can be stripped from the medium and captured in an acid solution, thus enabling the recovery of a valuable nutrient. The flux of ammonium across the membrane is characterized at different anolyte ammonium concentrations and currents for both the abiotic and biotic reactor systems. Both systems are compared based on current and removal efficiencies for ammonium, as well as the energy input required to drive ammonium transfer across the cation exchange membrane. Finally, a comparative analysis considering key aspects such as reliability, electrode cost, and rate is made. This video article and protocol provide the necessary information to conduct electrochemical and bioelectrochemical ammonia recovery experiments. The reactor setup for the two cases is explained, as well as the reactor operation. We elaborate on data analysis for both reactor types and on the advantages and disadvantages of bioelectrochemical and electrochemical systems. PMID:25651406

  14. A preliminary study on estimating extra-cellular nitrate reductase activities in estuarine systems

    OpenAIRE

    Pant H. K.

    2009-01-01

    Enzymes catalyzing ammonium (NH4+)/nitrate (NO3–) into nitrous oxide (N2O)/molecular nitrogen (N2), play critical roles in water quality management. The objective of this paper was to investigate the role of extra-cellular enzymes in cycling of nitrogen (N) in aquatic systems. It appears that N in estuaries, salt marshes, etc., does not stay long enough to be available for uptake, thus, creating N limited conditions. This study showed that indigenous extra-cellular nitrate reductase along wit...

  15. Contribution to the Chemical and Technological Study of Ammonium Diuranate Precipitation

    International Nuclear Information System (INIS)

    The present work is designed to study the relationship between the conditions for precipitation by ammonia and the properties of ammonium diuranate obtained either from uranyl nitrate solution or from gaseous uranium hexafluoride. In each case the optimum processes are defined leading on the one hand to uranate which can afterwards be treated in a reduction- fluorination oven to give uranium tetrafluoride, and on the other hand to a uranate suitable for the production of a sinterable uranium oxide. In particular it is shown that the treatment of uranyl nitrate solutions by stoichiometric quantities of ammonia leads to the complete precipitation of the uranium leaving less than 1 mg/litre of uranium in the solution, whereas the treatment of uranium hexafluoride necessitates the use of at least 8 times the stoichiometric quantity. (author)

  16. Comparison of three aerosol sampling techniques and the differences in the nitrate determined by each

    International Nuclear Information System (INIS)

    Ambient aerosol samples were collected simultaneously with three different methods, one a size fractionated impactor sampler and two filter samplers. Infrared spectroscopy was used to analyze the collected aerosol using attenuated total internal reflection for the impactor samples and direct transmission through ultra-thin teflon membrane filters for the filter samples. All samples were analyzed as soon as possible after collection; some were reanalyzed after being stored in closed petri dishes for up to 10 days. A major purpose of the study was to evaluate the neutralization of acidic sulfate aerosols after sample collection by the filtration techniques. No acidic sulfate was found in any of the samples collected during the field study. However, significant differences were observed in the nitrate content of the samples collected by the different samplers. Also, in several samples collected with the ATR impactor the nitrate content decreased upon storage. In some cases the nitrate absorbance bands diminished to zero; in other cases the nitrate initially decreased and then remained stable; in yet another case, a high level of nitrate persisted over several days. The results indicate that two different types of nitrate compounds were present in the samples, one more ''volatile'' than the other, although the infrared spectra were consistent with both of them being ammonium nitrate

  17. Soil nitrate reducing processes – drivers, mechanisms for spatial variation and significance for nitrous oxide production

    Directory of Open Access Journals (Sweden)

    Madeline Eleanore Giles

    2012-12-01

    Full Text Available The microbial processes of denitrification and dissimilatory nitrate reduction to ammonium (DNRA are two important nitrate reducing mechanisms in soil, which are responsible for the loss of nitrate (NO3-¬ and production of the potent greenhouse gas, nitrous oxide (N2O. A number of factors are known to control these processes, including O2 concentrations and moisture content, N, C, pH and the size and community structure of nitrate reducing organisms responsible for the processes. There is an increasing understanding associated with many of these controls on flux through the nitrogen cycle in soil systems. However, there remains uncertainty about how the nitrate reducing communities are linked to environmental variables and the flux of products from these processes. The high spatial variability of environmental controls and microbial communities across small sub cm areas of soil may prove to be critical in determining why an understanding of the links between biotic and abiotic controls has proved elusive. This spatial effect is often overlooked as a driver of nitrate reducing processes. An increased knowledge of the effects of spatial heterogeneity in soil on nitrate reduction processes will be fundamental in understanding the drivers, location and potential for N2O production from soils.

  18. Nitrate storage and dissimilatory nitrate reduction by eukaryotic microbes

    DEFF Research Database (Denmark)

    Kamp, Anja; Høgslund, Signe; Risgaard-Petersen, Nils; Stief, Peter

    2015-01-01

    storage and dissimilatory nitrate reduction by diverse marine eukaryotes placed into an eco-physiological context. The advantage of intracellular nitrate storage for anaerobic energy conservation in oxygen-depleted habitats is explained and the life style enabled by this metabolic trait is described. A...

  19. Chemical synthesis of nanocrystalline magnesium aluminate spinel via nitrate-citrate combustion route

    Energy Technology Data Exchange (ETDEWEB)

    Saberi, Ali [Ceramic Division, Iran University of Science and Technology, Tehran (Iran, Islamic Republic of)], E-mail: ASaberi@IUST.ac.ir; Golestani-Fard, Farhad; Sarpoolaky, Hosein [Ceramic Division, Iran University of Science and Technology, Tehran (Iran, Islamic Republic of); Willert-Porada, Monika; Gerdes, Thorsten [Chair of Materials Processing, University of Bayreuth, Bayreuth (Germany); Simon, Reinhard [Chair of Ceramic Materials Engineering, University of Bayreuth, Bayreuth (Germany)

    2008-08-25

    Nanocrystalline magnesium aluminate spinel (MgAl{sub 2}O{sub 4}) was synthesized using metal nitrates, citric acid and ammonium solutions. The precursor and the calcined powders at different temperatures were characterized by X-ray diffraction (XRD), simultaneous thermal analysis (STA), Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), and transmission electron microscopy (TEM). The combustion mechanism was also studied by a quadrupole mass spectrometer (QMS) which coupled to STA. The generated heat through the combustion of the mixture of ammonium nitrate and citrate based complexes decreased the synthesis temperature of MgAl{sub 2}O{sub 4} spinel. The synthesized MgAl{sub 2}O{sub 4} spinel at 900 deg. C has faced shape with crystallite size in the range of 18-24 nm.

  20. Chemical synthesis of nanocrystalline magnesium aluminate spinel via nitrate-citrate combustion route

    International Nuclear Information System (INIS)

    Nanocrystalline magnesium aluminate spinel (MgAl2O4) was synthesized using metal nitrates, citric acid and ammonium solutions. The precursor and the calcined powders at different temperatures were characterized by X-ray diffraction (XRD), simultaneous thermal analysis (STA), Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), and transmission electron microscopy (TEM). The combustion mechanism was also studied by a quadrupole mass spectrometer (QMS) which coupled to STA. The generated heat through the combustion of the mixture of ammonium nitrate and citrate based complexes decreased the synthesis temperature of MgAl2O4 spinel. The synthesized MgAl2O4 spinel at 900 deg. C has faced shape with crystallite size in the range of 18-24 nm

  1. Alternative nitrate reduction pathways in experimentally fertilized New England salt marshes

    DEFF Research Database (Denmark)

    Uldahl, Anne; Banta, Gary Thomas; Boegh, Eva;

    ongoing ecosystem level nutrient additions experiments in two New England salt marshes, Plum Island Sound (NO3- additions since 2003) and Great Sippewissett Marsh (fertilizer additions since the 1970's) to examine the relative importance of these NO3- reduction pathways in salt marshes. Sediments from......Nitrate present or generated in any benthic ecosystem can be reduced by a number of microbial pathways, most notably denitrification, anaerobic ammonium oxidation (anammox) and dissimilatory nitrate reduction to ammonium (DNRA). The first two processes remove of biologically available N from...... the ecosystem in the form of gaseous N2, while the last process transforms of NO3- to another biologically available form, NH4+, and thus merely recycles N. Salt marshes are important ecosystems for the cycling, retention and removal of biologically available N transported from land to the oceans. We used...

  2. Vertical activity distribution of dissimilatory nitrate reduction in coastal marine sediments

    DEFF Research Database (Denmark)

    Behrendt, A.; de Beer, D.; Stief, P.

    2013-01-01

    The relative importance of two dissimilatory nitrate reduction pathways, denitrification (DEN) and dissimilatory nitrate reduction to ammonium (DNRA), was investigated in intact sediment cores from five different coastal marine field sites (Dorum, Aarhus Bight, Mississippi Delta, Limfjord...... reduction was clearly dominated by DEN (59-131% of the total NO3- reduced) rather than by DNRA, irrespective of the sedimentary inventories of electron donors such as organic carbon, sulfide, and iron. Highest ammonium production via DNRA, accounting for up to 8.9% of the total NO3- reduced, was found...... at a site with very high concentrations of total sulfide and NH4+ within and below the layer in which NO3- reduction occurred. Sediment from two field sites, one with low and one with high DNRA activity in the core incubations, was also used for slurry incubations. Now, in both sediments high DNRA activity...

  3. Extraction of erbium, thulium, ytterbium and lutetium(3) nitrates by the mixtures of tri-n-butyl phosphate and trialkylmethylammonium nitrate from water-salt solutions

    International Nuclear Information System (INIS)

    A study was made on extraction of rare earth nitrates by mixtures of tri-n-butyl phosphate and trialkylmethylammonium nitrate at different component ratios, T = 298.15 K and pH2. It was established that compounds of [Ln(NO3)3L3], (R4N)i[Ln(NO3)3+i] (i = 2, 3), (R4N)2[Ln(NO3)5L], (L - tri-n-butyl phosphate, R4H+-cation of quaternary ammonium base) composition formed in organic phase. The values of extraction constants of homogeneous and mixed solvates of rare earth metal (3) nitrates decrease in metal (3) series: Er > Tm > Yb > Lu. 13 refs.; 4 figs.; 3 tabs

  4. Extraction of erbium(3), thulium(3), ytterbium(3) and lutetium(3) nitrates by diisooctylmethylphosphonate and trialkylmethylammonium nitrate from aqua-salt solutions

    International Nuclear Information System (INIS)

    Rare earth metal(3) nitrate extraction by mixtures based on diisooctylmethylphosphonate and trialkylmethylammonium nitrate is studied under different component ratios, T = 298.15 K and pH2. It is ascertained that [Ln(NO3)33S], (R4N)i[Ln(NO3)3+i] (i = 2,3), (R4N)ix[Ln(NO3)3+i(3-i)S] (i = 1,2) composition compounds, where S is diisooctylmethylphosphonate, and R4N+ is a quartile ammonium base cation, are produced in an organic phase. Values of constants of rare earth metal (3) nitrate mixed solvate extraction obey the statistic factor and are reduced in the (3) metal series: Er > Tm > Yb> Lu. 12 refs.; 4 figs.; 1 tab

  5. Oxidimetric determination of uranium (6) in the presence of nitrates using nickel boride

    International Nuclear Information System (INIS)

    Technique for oxidimetric determination of uranium (6) in the presence of nitrates by means of reduction by nickel boride in sulfuric acid medium with successive uranium (4) titration by potassium permanganate was developed. Use of nickel boride enables during one analytic operation to transform NO3- ion to ammonium salts and to reduce U6+ to U4+ with oxidimetric termination of analysis. The period of uranium determination is decreased 7-10 times as compared with application of Jones regulator

  6. Optical spectra of thulium(III) ion in certain nitrate, sulphate and acetate complexes

    International Nuclear Information System (INIS)

    Optical spectral studies of Tm(III) ion in nitrate, sulphate, and acetate solutions of thulium, ammonium, magnesium, potassium and sodium have been made. Second derivative spectra recorded for the first time revealed interesting results in all the fifteen samples studied. Lifetimes of the laser lines have been estimated from the observed absorption intensities of lines of Tm(III). Splittings observed for certain bands have been successfully explained as arising from the superpositions of vibronic transitions on electronic spectra. (Auth.)

  7. [1-(Carboxymethylcyclohexyl]methanaminium nitrate

    Directory of Open Access Journals (Sweden)

    Elise J. C. de Vries

    2011-02-01

    Full Text Available The title compound, C9H18NO2+·NO3−, is an anhydrous nitrate salt of gabapentin, which is formed serendipitously in the presence of selected non-coordinating metals. The crystal structure involves extensive hydrogen bonding between the –NH3+ and –COOH groups and the nitrate anion.

  8. Evaluation of nitrate destruction methods

    International Nuclear Information System (INIS)

    A wide variety of high nitrate-concentration aqueous mixed [radioactive and Resource Conservation and Recovery Act (RCRA) hazardous] wastes are stored at various US Department of Energy (DOE) facilities. These wastes will ultimately be solidified for final disposal, although the waste acceptance criteria for the final waste form is still being determined. Because the nitrates in the wastes will normally increase the volume or reduce the integrity of all of the waste forms under consideration for final disposal, nitrate destruction before solidification of the waste will generally be beneficial. This report describes and evaluates various technologies that could be used to destroy the nitrates in the stored wastes. This work was funded by the Department of Energy's Office of Technology Development, through the Chemical/Physical Technology Support Group of the Mixed Waste Integrated Program. All the nitrate destruction technologies will require further development work before a facility could be designed and built to treat the majority of the stored wastes. Several of the technologies have particularly attractive features: the nitrate to ammonia and ceramic (NAC) process produces an insoluble waste form with a significant volume reduction, electrochemical reduction destroys nitrates without any chemical addition, and the hydrothermal process can simultaneously treat nitrates and organics in both acidic and alkaline wastes. These three technologies have been tested using lab-scale equipment and surrogate solutions. At their current state of development, it is not possible to predict which process will be the most beneficial for a particular waste stream

  9. 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.

  10. Benchmark binding energies of ammonium and alkyl-ammonium ions interacting with water. Are ammonium-water hydrogen bonds strong?

    Science.gov (United States)

    Vallet, Valérie; Masella, Michel

    2015-01-01

    Alkyl-ammonium ion/water interactions are investigated using high level quantum computations, yielding thermodynamics data in good agreement with gas-phase experiments. Alkylation and hydration lead to weaken the NHsbnd O hydrogen bonds. Upon complete hydration by four water molecules, their main features are close to those of the OHsbnd O bond in the isolated water dimer. Energy decomposition analyses indicate that hydration of alkyl-ammonium ions are mainly due to electrostatic/polarization effects, as for hard monoatomic cations, but with a larger effect of dispersion.

  11. NITRIFICATION OF UREA AND ASSIMILATION OF NITRATE IN SATURATED SOILS UNDER AEROBIC CONDITIONS

    Directory of Open Access Journals (Sweden)

    A. E. Ghaly

    2013-01-01

    Full Text Available The aim of this study was to investigate nitrification activity of urea and the assimilation of nitrate in a well aerated soil using perfusion technique with addition of glucose as an energy and carbon source. In this study, urea was rapidly nitrified by the bacteria in the saturated soil but its course of transformation to NO3 was not linear. There was an initial increase in the concentration of nitrite during the nitrification experiment which indicated that the conversion of nitrite to nitrate was appreciably slower than the rate of conversion of urea to nitrite. The rate of conversion of NH4+ to NO2- was faster than the rate of conversion of NO2- to NO3- in the first 12 days and as a result the nitrate concentration reached 2.72 µg/ml on the 12th day. After day 12, the concentration of NH4+ in solution declined significantly and the rate of conversion of NO2- to NO3- became faster than the rate of conversion of NH4+ to NO2-. The concentration of NO2-N in the solution reached zero on the 23rd day. The nitrification curve has the character of a sigmoid curve whose midpoint, which representing the most rapid rate of nitrification, fell at the point of half conversion of urea to nitrite. The curve asymptotically approaches a nitrate value that represents 98% conversion of urea into nitrate. The rest of the urea (NH4 has presumably been synthesized into bacterial cells. The initial pH of the soil was 7.7 due to the presence of NH4 which decreased gradually due to the production of NO3 reaching 6.9 by day 23. A nitrate reduction was observed under aerobic conditions. Denitrification did not proceed according to the known fact that O2 prevents the denitrifying organisms from producing the enzyme responsible for the process. The alternative pathway for nitrate reduction could be by assimilatory reduction where nitrate was converted to ammonium and then to cells. The removal of nitrate and production of ammonium caused a rise in the pH. The

  12. Ammonium removal pathways and microbial community in GAC-sand dual media filter in drinking water treatment

    Institute of Scientific and Technical Information of China (English)

    Shuo Feng; Shuguang Xie; Xiaojian Zhang; Zhiyu Yang; Wei Ding; Xiaobin Liao; Yuanyuan Liu; Chao Chen

    2012-01-01

    A GAC-sand dual media filter (GSF) was devised as an alternative solution for drinking water treatment plant to tackle the.raw water polluted by ammonium in place of expensive ozone-GAC processes or bio-pretreatments.The ammonium removal pathways and microbial community in the GSFs were investigated.The concentrations of ammonium,nitrite and nitrate nitrogen were monitored along the filter.Total inorganic nitrogen (TIN) loss occurred during the filtration.For 1 mg ammonium removal,the TIN loss was as high as 0.35 mg,DO consumption was 3.06 mg,and alkalinity consumption was 5.55 mg.It was assumed that both nitrification and denitrification processes occur in the filters to fit the TIN loss and low DO consumption.During the filtration,nitritation,nitrification and nitritation-anaerobic ammonium oxidation processes probably occur,while traditional nitrification and denitrification and simultaneous nitrification and denitrification processes may occur.In the GSFs,Nitrosomonas and Nitrospira are likely to be involved in nitrification processes,while Novosphingobium,Comamonadaceae and Oxalobacteraceae may be involved in denitrification processes.

  13. Fate of added nitrate and ammonium-nitrogen entering a Louisiana gulf coast swamp forest

    International Nuclear Information System (INIS)

    Added 15N labeled inorganic nitrogen was used to determine the significance of nitrification-denitrification in flooded swamp soil in removing nitrogen. Nitrogen-15 labeled (NH2)2SO4 and KNO3 were added to replicated plots in a swamp forest receiving agricultural runoff. Nitrous oxide and N2 fluxes were measured and maximum fluxes were estimated at 24g N/m2 x yr and 110 g N/m2 x yr, respectively. The capacity of the swamp forest to remove large quantities of nitrogen via nitrification-denitrification processes was demonstrated

  14. Understanding the mechanisms of chemical incompatibility ammonium nitrate by molecular modeling

    OpenAIRE

    Cagnina, Stefania

    2014-01-01

    Numerous chemical reactants tend to lead to undesired phenomena of incompatibility. In order to prevent the happening of those phenomena, a rapid and accurate identification of the incompatibilities is needed. Until now, experimental studies, which provide insightful, but limited information, were the only possible approach used for the study of incompatibilities. In this work a molecular modeling approach was used in order to complete and improve experimental results of incompatibility proce...

  15. Recovery of Ammonium Nitrate and Reusable Acetic Acid from Effluent Generated during HMX Production

    Directory of Open Access Journals (Sweden)

    V. D. Raut

    2004-04-01

    Full Text Available Production of HMX on commercial scale is mainly carried out by modified Bachmann process, and acetic acid constitutes major portion of effluenttspent liquor produced during this process. The recovery of glacial acetic acid from this spent liquor is essential to make the process commercially viable besides making it eco-friendly by minimising the quantity of disposable effluent. The recovery of glacial acetic acid from spent liquor is not advisable by simple distillation since it contains, in addition to acetic acid, a small fraction of nitric acid, traces of RDX, HMX, and undesired nitro compounds. The process normally involves neutralising the spent mother liquor with liquor ammonia and then distillating the ueutralised mother liquor under vacuum to recover dilute acetic acid (strength approx. 30 %. The dilute acetic acid, in turn, is concentrated to glacial acetic acid by counter current solvent extraction, followed by distillation. The process is very lengthy and the energy requirement is also veryhigh, rendering the process economically unviable. Hence, a novel method has been developed on bench-scale to obtain glacial acetic acid directly from the mother liquor after the second ageing process.

  16. SOIL NITRATE AND AMMONIUM THROUGH 2 YEARS OF SELECTIVE HERBIVORY AND CHRONIC NITROGEN ENRICHMENT

    Science.gov (United States)

    -The effects of increased amounts and flux of bioavailable nitrogenous compounds in the ecosystem is of great interest to ecological researchers and longstanding concern to land-managers. Excess nitrogen in the environment is associated with many large-scale environmental concer...

  17. Recovery of Ammonium Nitrate and Reusable Acetic Acid from Effluent Generated during HMX Production

    OpenAIRE

    V. D. Raut; R. S. Khopade; M. V. Rajopadhye; V. L. Narasimhan

    2004-01-01

    Production of HMX on commercial scale is mainly carried out by modified Bachmann process, and acetic acid constitutes major portion of effluenttspent liquor produced during this process. The recovery of glacial acetic acid from this spent liquor is essential to make the process commercially viable besides making it eco-friendly by minimising the quantity of disposable effluent. The recovery of glacial acetic acid from spent liquor is not advisable by simple distillation since it contains, in ...

  18. Seaweed diversity enhances nitrogen uptake via complementary use of nitrate and ammonium

    OpenAIRE

    Bracken, MES; Stachowicz, J J

    2006-01-01

    The consequences of declining biodiversity remain controversial, in part because many studies focus on a single metric of ecosystem functioning and fail to consider diversity's integrated effects on multiple ecosystem functions. We used tide pool microcosms as a model system to show that different conclusions about the potential effects of producer diversity on ecosystem functioning may result when ecosystem functions are measured separately vs. together. Specifically, we found that in divers...

  19. Differential growth response of Ulva lactuca to ammonium and nitrate assimilation

    DEFF Research Database (Denmark)

    Ale, Marcel Tutor; Mikkelsen, Jørn Dalgaard; Meyer, Anne S

    2011-01-01

    Controlled cultivation of marine macroalgal biomass such as Ulva species, notably Ulva lactuca, is currently studied for production of biofuels or functional food ingredients. In a eutrophic environment, this macrophyte is exposed to varying types of nutrient supply, including different and fluct...

  20. Plant architecture of Paspalum vaginatum schwartz modified by nitrate and ammonium nutrition

    Directory of Open Access Journals (Sweden)

    José Beltrano

    1999-07-01

    Full Text Available Paspalum vaginatum Schwartz plants were grown under greenhouse conditions in a continuous-flow hydroponic culture, containing NO3- or NH4+or NH4NO3 as nitrogen source. After 30 days, the size of aerial biomass and root system decreased significantly when plants were supplied with NH4+as exclusive nitrogen source. Compared to NO3- treatment, reducing and non-reducing sugars were decreasing together with a significant increase in amino acids content. NH4+-nutrition caused tillers to grow toward an orthogravitropic position (average angle of 68° with respect to the horizontal, and with NO3--nutrition, tillers tended to become diagravitropic (average angle of 23°. With NH4NO3 all the parameters measured had values in between those of the other two sources. Thus, the morphologic differences among plants growing in NO3- or NH4+ nutrition confirm the hypothesis that nitrogen source determines the growth habit of tillers in P. vaginatum by modulating the endogenous levels of reducing-non-reducing sugars.

  1. Potato uptake and recovery of nitrogen-15-enriched ammonium nitrate from periodic applications

    International Nuclear Information System (INIS)

    There is a trend in potato (Solanum tuberosum L.) production to make repeated additions of N fertilizer in sprinkler irrigation water for an extended part of the season. More information is needed on scheduling (rate and timing) these N supplements. A 3-year study on the use of frequent supplements of 15NH4-15NO3 by 'Russet Burbank' potato was conducted on Quincy loamy sand (mixed, mesic Xeric Torripsamment). The purpose of the experiment was to trace changes in the uptake and partitioning of 15N in vines and tubers from starter and periodic additions totaling 336 kg N ha-1. Labeled N fertilizer was sprayed on a different set of replicated potato plots according to the application schedule. Plant tissue samples were taken and analyzed regularly for labeled N uptake. Whole potato plants over the season recovered a maximum of 61 to 67% of the 15N-enriched increments of fertilizer applied, as compared to a maximum of 42 to 54% partitioning of the labeled N in tubers at final harvest. Recovery of 15NO3 was significantly higher on the average than recovery for 15NH4. Furthermore, in many cases the average recovery was highest from labeled N applied tuber bulking early in July, which suggests that this is a crucial time for maintaining adequate N fertility

  2. The Influence of Iron on Ammonium Ion Generation from Nitrate Ion in Liquid Phase

    Institute of Scientific and Technical Information of China (English)

    Youhei Kinoshita; Naoki Okumura; Kazunori Takashima; Shinji Katsura; Akira Mizuno

    2005-01-01

    Flue gas cleaning in discharge plasma process has been studied intensively and we have tried to remove the NOx and SO2 using the wet-type plasma reactor. In this system, NO is oxidized to NO2 and absorbed as NO-3, and SO2 is absorbed as SO32- and oxidized in the liquid to SO42-. But the concentration of NO-3 was saturated and the absorption of NOx and SO2 was inhibited. Then, the reduction of NO-3 in the liquid is required. We examined the reductive reaction of NO-3 to NH4+ using discharge above the liquid surface then the pH value of the liquid was changed to alkaline slightly. When the Fe plate was used as a ground electrode in the liquid,NH4+ was generated. Then, the relation between the generation of NH4+ and Fe ions (Fe2+ and Fe3+) was studied. When Fe2+ was presented in the liquid, NH4+ was generated and Fe2+ was oxidized to Fe3+. Fe2+ is required to generate NH4+ from NO-3. When NH4+ was generated from NO-3, both the calculated pH value from NH4+ concentration and the measured pH value indicated a similar value. From these results, the discharge above the liquid surface was effective to convert NO-3 to NH4+ and the reductive reaction leads to more absorption of NO-3. These results showed that the wet-type plasma reactor is effective for NOx and SO2 removal system.

  3. Ammonium and nitrate uptake by soybean during recovery from nitrogen deprivation

    Science.gov (United States)

    Rideout, J. W.; Chaillou, S.; Raper, C. D. Jr; Raper CD, J. r. (Principal Investigator)

    1994-01-01

    Soybean [Glycine max (L.) Merrill] plants that had been subjected to 15 d of nitrogen deprivation were resupplied for 10 d with 1.0 mol m-3 nitrogen provided as NO3-, NH4+, or NH4(+) + NO3- in flowing hydroponic culture. Plants in a fourth hydroponic system received 1.0 mol m-3 NO3- during both stress and resupply periods. Concentrations of soluble carbohydrates and organic acids in roots increased 210 and 370%, respectively, during stress. For the first day of resupply, however, specific uptake rates of nitrogen, determined by ion chromatography as depletion from solution, were lower for stressed than for non-stressed plants by 43% for NO3- resupply, by 32% for NH4(+) + NO3- resupply, and 86% for NH4+ resupply. When specific uptake of nitrogen for stressed plants recovered to rates for non-stressed plants at 6 to 8 d after nitrogen resupply, carbohydrates and organic acids in their roots had declined to concentrations lower than those of non-stressed plants. Recovery of nitrogen uptake capacity of roots thus does not appear to be regulated simply by the content of soluble carbon compounds within roots. Solution concentrations of NH4+ and NO3- were monitored at 62.5 min intervals during the first 3 d of resupply. Intermittent 'hourly' intervals of net influx and net efflux occurred. Rates of uptake during influx intervals were greater for the NH4(+)-resupplied than for the NO3(-)-resupplied plants. For NH4(+)-resupplied plants, however, the hourly intervals of efflux were more numerous than for NO3(-)-resupplied plants. It thus is possible that, instead of repressing NH4+ influx, increased accumulation of amino acids and NH4+ in NH4(+)-resupplied plants inhibited net uptake by stimulation of efflux on NH4+ absorbed in excess of availability of carbon skeletons for assimilation. Entry of NH4+ into root cytoplasm appeared to be less restricted than translocation of amino acids from the cytoplasm into the xylem.

  4. Root-zone acidity affects relative uptake of nitrate and ammonium from mixed nitrogen sources

    Science.gov (United States)

    Vessey, J. K.; Henry, L. T.; Chaillou, S.; Raper, C. D. Jr; Raper CD, J. r. (Principal Investigator)

    1990-01-01

    Soybean plants (Glycine max [L.] Merr. cv Ransom) were grown for 21 days on 4 sources of N (1.0 mM NO3-, 0.67 mM NO3- plus 0.33 mM NH4+, 0.33 mM NO3- plus 0.67 mM NH4+, and 1.0 mM NH4+) in hydroponic culture with the acidity of the nutrient solution controlled at pH 6.0, 5.5, 5.0, and 4.5. Dry matter and total N accumulation of the plants was not significantly affected by N-source at any of the pH levels except for decreases in these parameters in plants supplied solely with NH4+ at pH 4.5. Shoot-to-root ratios increased in plants which had an increased proportion [correction of proporiton] of NH4(+)-N in their nutrient solutions at all levels of root-zone pH. Uptake of NO3- and NH4+ was monitored daily by ion chromatography as depletion of these ions from the replenished hydroponic solutions. At all pH levels the proportion of either ion that was absorbed increased as the ratio of that ion increased in the nutrient solution. In plants which were supplied with sources of NO3- plus NH4+, NH4+ was absorbed at a ratio of 2:1 over NO3- at pH 6.0. As the pH of the root-zone declined, however, NH4+ uptake decreased and NO3- uptake increased. Thus, the NH4+ to NO3- uptake ratio declined with decreases in root-zone pH. The data indicate a negative effect of declining root-zone pH on NH4+ uptake and supports a hypothesis that the inhibition of growth of plants dependent on NH4(+)-N at low pH is due to a decline in NH4+ uptake and a consequential limitation of growth by N stress.

  5. 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

  6. Occupational Exposure in Ammonium Phosphate Fertilizer Plants

    International Nuclear Information System (INIS)

    Occupational exposures and activity concentrations have been assessed in two industrial plants producing mono-ammonium phosphate and di-ammonium phosphate fertilizers, located in south-western Spain. The annual effective doses received by the workers are below 1 mSv/a, with the contribution from external exposure being similar to that from internal exposure. The dose contribution from inhalation of dust has been estimated to be about 0.12 mSv/a, while the 222Rn concentrations inside the plants are of no concern. Consequently, no additional radiation protection measures need to be taken to protect the workers in these facilities. (author)

  7. 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.

  8. Transition Metal Carbohydrazide Nitrates: Burn-rate Modifiers for Propellants

    Directory of Open Access Journals (Sweden)

    S. H. Sonawane

    2006-07-01

    Full Text Available This paper discusses the synthesis and characterisation of cobalt (Co, nickel (Ni andcopper (Cu carbohydrazide nitrates. In differential scanning calorimetry (DSC, the complexesexhibited exothermic decomposition indicating their energetic nature. The commencement ofdecomposition was observed at 220 °C for Ni complex, and at 160 °C for Co complex whereasthat of Cu complex occurred at 75 °C. In view of the better thermal stability, Ni and Co complexeswere selected for further study. The activation energy of decomposition of Ni and Co complexeswere found to be 47 kcal/mol and 60 kcal/mol respectively. Impact and friction sensitivity testresults revealed relatively lower vulnerability of carbohydrazide cobalt nitrate. Its incorporationin an ammonium perchlorate (AP-based composite propellant led to 9-19 per cent enhancementwhereas that of carbohydrazide nickel nitrate resulted in 28-74 per cent enhancement in burningrates in the pressure range 1.9 MPa to 8.8 MPa. Exothermic decomposition of the coordinationcomplexes on propellant surface and involvement of metal at molecular level formed ondecomposition of the complexes in combustion environment of composite propellant may beattributed to the catalytic effect of this class of compounds on the lines of reported literature.

  9. 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.

  10. Ammonium first: natural mosses prefer atmospheric ammonium but vary utilization of dissolved organic nitrogen depending on habitat and nitrogen deposition.

    Science.gov (United States)

    Liu, Xue-Yan; Koba, Keisuke; Makabe, Akiko; Li, Xiao-Dong; Yoh, Muneoki; Liu, Cong-Qiang

    2013-07-01

    Mosses, among all types of terrestrial vegetation, are excellent scavengers of anthropogenic nitrogen (N), but their utilization of dissolved organic N (DON) and their reliance on atmospheric N remain uncharacterized in natural environments, which obscures their roles in N cycles. Natural (15) N abundance of N sources (nitrate (NO(3)(-)), ammonium (NH(4)(+)) and DON in deposition and soil) for epilithic and terricolous mosses was analyzed at sites with different N depositions at Guiyang, China. Moss NO(3)(-) assimilation was inhibited substantially by the high supply of NH(4)(+) and DON. Therefore, contributions of NH(4)(+) and DON to moss N were partitioned using isotopic mass-balance methods. The N contributions averaged 56% and 46% from atmospheric NH(4)(+), and 44% and 17% from atmospheric DON in epilithic and terricolous mosses, respectively. In terricolous mosses, soil NH(4)(+) and soil DON accounted for 16% and 21% of bulk N, which are higher than current estimations obtained using (15) N-labeling methods. Moreover, anthropogenic NH(4)(+) deposition suppressed utilization of DON and soil N because of the preference of moss for NH(4)(+) under elevated NH(4)(+) deposition. These results underscore the dominance of, and preference for, atmospheric NH(4)(+) in moss N utilization, and highlight the importance of considering DON and soil N sources when estimating moss N sequestration and the impacts of N deposition on mosses. PMID:23692546

  11. Excess nitrate loads to coastal waters reduces nitrate removal efficiency

    DEFF Research Database (Denmark)

    Lunau, Mirko; Voss, Maren; Erickson, Matthew;

    2013-01-01

    Terrestrial ecosystems are becoming increasingly nitrogen-saturated due to anthropogenic activities, such as agricultural loading with artificial fertilizer. Thus, more and more reactive nitrogen is entering streams and rivers, primarily as nitrate, where it is eventually transported towards the ...

  12. Assimilation of upwelled nitrate by small eukaryotes in the Sargasso Sea

    Science.gov (United States)

    Fawcett, Sarah E.; Lomas, Michael W.; Casey, John R.; Ward, Bess B.; Sigman, Daniel M.

    2011-10-01

    Phytoplankton growth is potentially limited by the scarcity of biologically available forms of nitrogen such as nitrate and ammonium. In the subtropical ocean gyres, water column stratification impedes the upward flux of nitrate to surface waters. Phytoplankton in these waters are assumed to rely largely on ammonium and other forms of nitrogen recycled during the breakdown of organic matter. Here, we use flow cytometry to separate prokaryotic and eukaryotic phytoplankton collected from Sargasso Sea surface waters in the summers of 2008 and 2009, and to analyse their respective nitrogen isotope ratios. We show that prokaryotes have a uniformly low ratio of 15N to 14N, δ15N, consistent with their reliance on recycled nitrogen. In contrast, small eukaryotic phytoplankton, less than 30μm in size, have a higher and more variable δ15N, with a mean value similar to that of nitrate in underlying Subtropical Mode Water. For the summertime Sargasso Sea, we estimate that small eukaryotes obtain more than half of their nitrogen from upwelled nitrate. In addition, our data support the view that sinking material derives largely from eukaryotic, not prokaryotic, phytoplankton biomass.

  13. Extraction of lanthanide (3) nitrates by trialkylmethylammonium nitrate in decane

    International Nuclear Information System (INIS)

    Extraction of lanthanide (3) nitrates (praseodymium (3) - lutetium (3)) by trialkylmethylammonium nitrate in decane at T=298.15 K and pH2 is studied. The extraction isotherms are described with an account of formation of compounds of the (R4N)i(Ln(NO3)3+i) composition. Extraction constants values, which become reduced in the praseodymium (3)-lutetium (3) series, are calculated

  14. Rare earth(3) nitrates extraction with trialkylmethylammonium nitrate in toluene

    International Nuclear Information System (INIS)

    Extraction of rare earth(3) nitrates [praseodymium(3)-lutetium(3)] with trialkylmethylammonium nitrate in toluene at T = 298.15 K and pH 2 is studied. Extraction isotherms are described with regard to formation of compounds of (R4N)i[Ln(NO3)3+i] composition (i = 2, 3) in organic phase. Values of extraction constants are calculated, they are decreasing in the praseodymium(3) - lutetium(3) series

  15. Scandium extraction by methyltrialkylammonium nitrate from nitrate solutions

    International Nuclear Information System (INIS)

    Chemistry of scandium extraction by methyltrialkylammonium (MTAA) nitrate in toluene from nitrate solutions is studied. Methods of saturation, equilibrium shift, physicochemical analysis, isomolar series and UV-spectroscopy are used to determine the composition of extracted complexes. It is shown that with low saturation degrees of extractant (R4N)6Sc(NO3)9 complex is formed in organic phase and with saturation - (R4N)3xSc(NO3)6 complex

  16. Genetic control of nitrate assimilation in Klebsiella oxytoca. Final technical report

    Energy Technology Data Exchange (ETDEWEB)

    Stewart, Valley J.

    2001-04-01

    Some microorganisms can use nitrate as the sole source of nitrogen for biosynthesis. This project focused on the bacterium Klebsiella oxytoca, an enterobacterium found in soil and water. Mutagenesis and molecular cloning identified the nasFEDCBA operon encoding enzymes for the uptake and reduction of nitrate and nitrite to ammonium, and the adjacent nasR regulatory gene. Analysis of nasF operon expression revealed that transcription is activated by the Ntr (general nitrogen regulation ) system in response to nitrogen limitation. Transcription antitermination control in response to nitrate and nitrite is mediated by the NasR protein. Additional work established that the NasR protein is an RNA-binding protein that interacts with nasF operon leader RNA to control transcription readthrough.

  17. Genetic control of nitrate assimilation in Klebsiella oxytoca. Final technical report; FINAL

    International Nuclear Information System (INIS)

    Some microorganisms can use nitrate as the sole source of nitrogen for biosynthesis. This project focused on the bacterium Klebsiella oxytoca, an enterobacterium found in soil and water. Mutagenesis and molecular cloning identified the nasFEDCBA operon encoding enzymes for the uptake and reduction of nitrate and nitrite to ammonium, and the adjacent nasR regulatory gene. Analysis of nasF operon expression revealed that transcription is activated by the Ntr (general nitrogen regulation ) system in response to nitrogen limitation. Transcription antitermination control in response to nitrate and nitrite is mediated by the NasR protein. Additional work established that the NasR protein is an RNA-binding protein that interacts with nasF operon leader RNA to control transcription readthrough

  18. Montmorillonite modification by quaternary ammonium epoxide

    Czech Academy of Sciences Publication Activity Database

    Duchek, P.; Špírková, Milena; Šabata, Stanislav

    Kochi: India n Society of Nanoscience And Nanotechnology, 2010. s. 1. [Nanotech India 2010. 19.11.2010-21.11.2010, Kochi] R&D Projects: GA AV ČR(CZ) IAAX08240901 Institutional research plan: CEZ:AV0Z40500505; CEZ:AV0Z40720504 Keywords : montmorillonite * quaternary ammonium epoxide * intercalation Subject RIV: JI - Composite Materials

  19. 21 CFR 184.1135 - Ammonium bicarbonate.

    Science.gov (United States)

    2010-04-01

    ... ingredient meets the specifications of the Food Chemicals Codex, 3d Ed. (1981), p. 19, which is incorporated... 21 Food and Drugs 3 2010-04-01 2009-04-01 true Ammonium bicarbonate. 184.1135 Section 184.1135 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED)...

  20. 21 CFR 184.1139 - Ammonium hydroxide.

    Science.gov (United States)

    2010-04-01

    ... specifications of the Food Chemicals Codex, 3d Ed. (1981), p. 20, which is incorporated by reference. Copies are... 21 Food and Drugs 3 2010-04-01 2009-04-01 true Ammonium hydroxide. 184.1139 Section 184.1139 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) FOOD...

  1. 21 CFR 184.1143 - Ammonium sulfate.

    Science.gov (United States)

    2010-04-01

    ... the specifications of the “Food Chemicals Codex,” 3d Ed. (1981), pp. 22-23, which is incorporated by... 21 Food and Drugs 3 2010-04-01 2009-04-01 true Ammonium sulfate. 184.1143 Section 184.1143 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) FOOD...

  2. 21 CFR 184.1137 - Ammonium carbonate.

    Science.gov (United States)

    2010-04-01

    ... of the Food Chemicals Codex, 3d Ed. (1981), p. 19, which is incorporated by reference. Copies are... 21 Food and Drugs 3 2010-04-01 2009-04-01 true Ammonium carbonate. 184.1137 Section 184.1137 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) FOOD...

  3. Degradation mechanism and thermal stability of urea nitrate below the melting point

    International Nuclear Information System (INIS)

    Highlights: → Decomposition mechanism of urea nitrate. → Spectral characterization of the decomposition mechanism. → Thermal stability of urea nitrate at 50, 70 and 100 oC. → Chemical balance of decomposed products released. - Abstract: Aging and degradation of urea nitrate below the melting point, at 100 oC, was studied by using thermal analysis and spectroscopic methods including IR, Raman, 1H and 13C NMR techniques. It was found that urea nitrate was completely degraded after 72 h at 100 oC into a mixture of solids (69%) and released gaseous species (31%). The degradation mechanism below the melting point was clearly identified. The remaining solid mixture was composed of ammonium nitrate, urea and biuret while unreacted residual nitric and isocyanic acids as well as traces of ammonia were released as gaseous species at 100 oC. The thermal stability of urea nitrate, under extreme storage conditions (50 oC), was also examined by isothermal nano-calorimetry.

  4. Effects of nitrate on nuclide solubility for co-location disposal of TRU waste and HLW

    International Nuclear Information System (INIS)

    Part of TRU waste includes a large amount of nitrate salt, the effects of which have to be evaluated in a safety assessment of co-location disposal with high level radioactive waste (HLW). High concentrations of nitrate ions from TRU waste might affect the solubility of different radionuclides in the HLW. In the current study, the effects of nitrate salt on radionuclide solubility were investigated experimentally. Solubility experiments of important and redox sensitive radionuclides, Tc(IV), Np(IV) and Se(0), were performed using various concentrations of sodium nitrate (NaNO3) and of Np(V) in NaNO3 solutions to investigate complex formation with NO3- ions. Solubility experiments of Pd(II), Sn(IV) and Nb(V) using ammonium chloride (NH4Cl) solution were also undertaken to investigate complex formation with NH3/NH4+ ions. No significant solubility enhancement was observed for Np and Se. Tc solubility in ≥0.1 mol/dm3 NaNO3 solution increased due to oxidation by nitrate ions. An increase of Np(V) solubility was expected by the chemical equilibrium model calculation with JNC-TDB, however, solubility enhancement by complex formation of Np(V) with nitrate ions was not observed. Solubility enhancement by complex formation of Sn and Nb were also not observed, only Pd solubility was increased by complex formation with NH3/NH4+ ions. (author)

  5. Redefining the importance of nitrate during haze pollution to help optimize an emission control strategy

    Science.gov (United States)

    Pan, Yuepeng; Wang, Yuesi; Zhang, Junke; Liu, Zirui; Wang, Lili; Tian, Shili; Tang, Guiqian; Gao, Wenkang; Ji, Dongsheng; Song, Tao; Wang, Yonghong

    2016-09-01

    Nitrate salts represent a major component of fine mode aerosols, which play an important role in air pollution worldwide. Based on on-line and off-line aerosol measurements in urban Beijing for both clean and haze conditions, we demonstrate that the absolute and relative concentrations of nitrate increased with visibility degradation (relative humidity), whereas the variations of organics tracked the patterns of mixing-layer height and temperature. We propose that the increase in the relative contribution of nitrate to PM1 observed during the early stages of haze pollution was due to new particle formation, whereas the nitrate formed in PM1-2.5 during the latter stages was due to heterogeneous formation and hygroscopic growth. The increasing trend of nitrate (and also sulfate and ammonium) but decreasing trends of organics during haze development, together with the increase of the NO2/SO2 molar ratio with increasing proximity to downtown Beijing and with visibility degradation, provide further evidence that controlling NOx emissions should be a priority for improving air quality in mega cities. Additional large-scale investigation is required to adequately characterize the regional features of NOx-induced haze pollution in China. Such studies may provide insight into the formation of critical nuclei or the subsequent growth of freshly nucleated particles and advance our understanding of the role of nitrate in new particle formation.

  6. Effect of ammonium compounds on dissolution rate of South African calcium-based material.

    Science.gov (United States)

    Rutto, Hillary; Siagi, Zachariah; Mbarawa, M

    2009-09-15

    The rate at which limestone dissolves is very important in wet flue gas desulphurisation process (FGD). High dissolution rates provide better alkalinity that is important for sulphur dioxide (SO(2)) absorption. The dissolution characteristics have been studied by using a pH-Stat method at 60 degrees C, at pH value of 5, stirrer speed of 100 rpm and particle size of 44 microm. This paper examines the use of ammonium compound as the possible additives that will enhance the dissolution rate of limestone. The dissolution rates were measured according to the shrinking core model with surface control, i.e. (1-(1-X)(1/3))=k(r)t. It was found that the dissolution rate increases in the presence of ammonium compounds. Upon addition of 0.5 g of ammonium nitrate, the dissolution rate constants increased by 170%. As the pH is increased the dissolution rate decreases. The dissolution reaction follows a shrinking core model with the chemical reaction control as the rate-controlling step. PMID:19447546

  7. 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).

  8. Supplementary calcium ameliorates ammonium toxicity by improving water status in agriculturally important species.

    Science.gov (United States)

    Hernández-Gómez, Elvia; Valdez-Aguilar, Luis A; Cartmill, Donita L; Cartmill, Andrew D; Alia-Tajacal, Irán

    2015-01-01

    Fertilization of agricultural plants with ammonium [Formula: see text] is often desirable because it is less susceptible to leaching than nitrate [Formula: see text] reducing environmental pollution, risk to human health and economic loss. However, a number of important agricultural species exhibit a reduction in growth when fertilized with [Formula: see text] and increasing the tolerance to [Formula: see text] may be of importance for the establishment of sustainable agricultural systems. The present study explored the feasibility of using calcium (Ca) to increase the tolerance of bell pepper (Capsicum annuum) to [Formula: see text] fertilization. Although [Formula: see text] at proportions ≥25 % of total nitrogen (N) decreased leaf dry mass (DM), supplementary Ca ameliorated this decrease. Increasing [Formula: see text] resulted in decreased root hydraulic conductance (Lo) and root water content (RWC), suggesting that water uptake by roots was impaired. The [Formula: see text]-induced reductions in Lo and RWC were mitigated by supplementary Ca. Ammonium induced increased damage to the cell membranes through lipid peroxidation, causing increased electrolyte leakage; Ca did not reduce lipid peroxidation and resulted in increased electrolyte leakage, suggesting that the beneficial effects of Ca on the tolerance to [Formula: see text] may be more of a reflection on its effect on the water status of the plant. Bell pepper plants that received [Formula: see text] had a low concentration of [Formula: see text] in the roots but a high concentration in the leaves, probably due to the high nitrate reductase activity observed. Ammonium nutrition depressed the uptake of potassium, Ca and magnesium, while increasing that of phosphorus. The results obtained in the present study indicate that [Formula: see text] caused growth reduction, nutrient imbalance, membrane integrity impairment, increased activity of antioxidant enzymes and affected water relations. Supplementary Ca

  9. Biological denitrification of nitrate wastes

    International Nuclear Information System (INIS)

    Enriched uranium wastes are purified in the Y-12 Plant, and the uranium product is recycled. One purification method involves dissolving the waste in nitric acid followed by solvent extraction to recover uranium. The process generates nitrate waste solutions which must be discarded. For many years, these wastes were stored in unlined ponds. In 1976 a recycle process was installed, and about half of the wastes were recovered and reused. A biological process (stirred tank) was installed, and the remaining nitrate wastes were biologically decomposed to produce nitrogen gas. Some additional nitrate wastes, generated in other parts of the plant, continued to be placed in the open ponds which must now be decommissioned. In 1983 an in-situ biological process was developed and tested whereby the open ponds were successfully biologically treated. This paper describes the results of the stirred tank and the in-situ pond treatment processes used in the plant to decompose nitrate ions

  10. Nitrate contamination of groundwater in the catchment of Goczałkowice reservoir

    Science.gov (United States)

    Czekaj, Joanna; Witkowski, Andrzej J.

    2014-05-01

    Goczałkowice dammed reservoir (area - 26 km2 , volume - 100 million m3 at a typical water level) is a very important source of drinking water for Upper Silesian agglomeration. At the catchment of the reservoir there are many potential sources of groundwater pollution (agriculture, bad practices in wastewater management, intensive fish farming). Thus local groundwater contamination, mainly by nitrogen compounds. The paper presents groundwater monitoring system and preliminary results of the research carried on at Goczałkowice reservoir and its catchment in 2010 - 2014 within the project "Integrated system supporting management and protection of dammed reservoir (ZiZoZap)'. The main objective for hydrogeologists in the project is to assess the role of groundwater in total water balance of the reservoir and the influence of groundwater on its water quality. During research temporal variability of groundwater - surface water exchange has been observed. Monitoring Network of groundwater quality consists of 22 observation wells (nested piezometers included) located around the reservoir - 13 piezometers is placed in two transects on northern and southern shore of reservoir. Sampling of groundwater from piezometers was conducted twice - in autumn 2011 and spring 2012. Maximum observed concentrations of nitrate, nitrite and ammonium were 255 mg/L, 0,16 mg/L and 3,48 mg/L, respectively. Surface water in reservoir (8 points) has also been sampled. Concentrations of nitrate in groundwater are higher than in surface water. Nitrate and ammonium concentrations exceeding standards for drinking water were reported in 18% and 50% of monitored piezometers, respectively. High concentration of nitrate (exceeding more than 5 times maximal admissible concentration) have been a significant groundwater contamination problem in the catchment of the reservoir. Periodically decrease of surface water quality is possible. Results of hydrogeological research indicate substantial spatial

  11. Impact of mineral dust on nitrate, sulfate, and ozone in transpacific Asian pollution plumes

    Directory of Open Access Journals (Sweden)

    T. D. Fairlie

    2010-04-01

    Full Text Available We use a 3-D global chemical transport model (GEOS-Chem to interpret aircraft observations of nitrate and sulfate partitioning in transpacific dust plumes during the INTEX-B campaign of April–May 2006. The model includes explicit transport of size-resolved mineral dust and its alkalinity, nitrate, and sulfate content. The observations show that particulate nitrate is primarily associated with dust, sulfate is primarily associated with ammonium, and Asian dust remains alkaline across the Pacific. This can be reproduced in the model by using a reactive uptake coefficient for HNO3 on dust (γ(HNO3 ~10−3 much lower than commonly assumed in models and possibly reflecting limitation of uptake by dust dissolution. The model overestimates gas-phase HNO3 by a factor of 2–3, typical of previous model studies; we show that this cannot be corrected by uptake on dust. We find that the fraction of aerosol nitrate on dust in the model increases from ~30% in fresh Asian outflow to 80–90% over the Northeast Pacific, reflecting in part the volatilization of ammonium nitrate and the resulting transfer of nitrate to the dust. Consumption of dust alkalinity by uptake of acid gases in the model is slow relative to the lifetime of dust against deposition, so that dust does not acidify (at least not in the bulk. This limits the potential for dust iron released by acidification to become bio-available upon dust deposition. Observations in INTEX-B show no detectable ozone depletion in Asian dust plumes, consistent with the model. Uptake of HNO3 by dust, suppressing its recycling to NOx, reduces Asian pollution influence on US surface ozone in the model by 10–15% or up to 1 ppb.

  12. Impact of mineral dust on nitrate, sulfate, and ozone in transpacific Asian pollution plumes

    Directory of Open Access Journals (Sweden)

    L. Zhang

    2009-11-01

    Full Text Available We use a 3-d global chemical transport model (GEOS-Chem to interpret aircraft observations of nitrate and sulfate partitioning in transpacific dust plumes during the INTEX-B campaign of April–May 2006. The model includes explicit transport of size-resolved mineral dust and its alkalinity, nitrate, and sulfate content. The observations show that particulate nitrate is primarily associated with dust, sulfate is primarily associated with ammonium, and Asian dust remains alkaline across the Pacific. This can be reproduced in the model by using a reactive uptake coefficient for HNO3 on dust (γ(HNO3~10−3 much lower than commonly assumed in models and likely reflecting limitation of uptake by dust dissolution. The model overestimates gas-phase HNO3 by a factor of 2–3, typical of previous model studies; we show that this cannot be corrected by uptake on dust. We find that the fraction of aerosol nitrate on dust in the model increases from ~30% in fresh Asian outflow to 80–90% over the Northeast Pacific, reflecting in part the volatilization of ammonium nitrate and the resulting transfer of nitrate to the dust. Consumption of dust alkalinity by uptake of acid gases in the model is slow relative to the lifetime of dust against deposition, so that dust in general does not acidify. This argues against the hypothesis that dust iron released by acidification could become bio-available upon dust deposition. Observations in INTEX-B show no detectable ozone depletion in Asian dust plumes, consistent with the model. Uptake of HNO3 by dust, suppressing its recycling to NOx, reduces Asian pollution influence on US surface ozone in the model by 10–15% or up to 1 ppb.

  13. 40 CFR 721.4095 - Quaternary ammonium alkyltherpropyl trialkylamine halides.

    Science.gov (United States)

    2010-07-01

    ... trialkylamine halides. 721.4095 Section 721.4095 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY... Specific Chemical Substances § 721.4095 Quaternary ammonium alkyltherpropyl trialkylamine halides. (a... generically as quaternary ammonium alkyltherpropyl trialkylamine halides (PMNs...

  14. NOx and ammonium isotopic fingerprints of anammox in natural and engineered systems: Implications for N isotope budgets and the use of NOx isotopes to diagnose process stability in wastewater treatment

    Science.gov (United States)

    Lehmann, M. F.; Stöcklin, N.; Brunner, B.; Frame, C. H.; Joss, A.; Kipf, M.; Kuhn, T.; Wunderlin, P.

    2014-12-01

    The anaerobic oxidation of ammonium with nitrite (anammox) has been identified as a very important fixed nitrogen (N) sink, accounting for a large fraction of global fixed N loss in marine, freshwater, and semi-terrestrial environments. In engineered systems, combined nitritation-anammox is an efficient process to remove N from ammonium-rich wastewater, with nitrite as the central intermediate. During the anammox process, nitrate is being produced, providing reducing equivalents for carbon fixation. Measuring the N isotope ratios in fixed N species (i.e., ammonium, nitrite, nitrate) has proven to be a valuable tool to track N cycling in freshwater and marine ecosystems, yet its application in wastewater treatment as a tool to diagnose nitrate production pathways is novel. In this presentation we will elucidate, and compare, the N isotope effects associated with anammox 1) in vitro, 2) in a lacustrine setting, and 3) in a small-scale batch reactor for wastewater treatment. We demonstrate that the anammox nitrite/nitrate isotopic signatures are modulated by the superposition of strong kinetic (normal and inverse) and equilibrium (nitrite-nitrate) N isotope fractionation. The ammonium N isotope effect is driven by kinetic N isotope fractionation, and is similar to that of nitrification. We will discuss the possible controls on the expression of the anammox N isotope effects in the natural environment. We will also evaluate the use of nitrate/nitrite N (and O) isotope signatures to distinguish between nitrate production by anammox versus nitrite oxidation, which is important for optimizing process efficiency during wastewater treatment.

  15. 40 CFR 721.10099 - Dialkyl dimethyl ammonium carbonate (generic).

    Science.gov (United States)

    2010-07-01

    ... 40 Protection of Environment 30 2010-07-01 2010-07-01 false Dialkyl dimethyl ammonium carbonate... Specific Chemical Substances § 721.10099 Dialkyl dimethyl ammonium carbonate (generic). (a) Chemical... as dialkyl dimethyl ammonium carbonate (1:1) (PMN P-03-715) is subject to reporting under...

  16. Quantifying the effects of clear-cutting and strip-cutting on nitrate dynamics in a forested watershed using triple oxygen isotopes as tracers

    Directory of Open Access Journals (Sweden)

    U. Tsunogai

    2014-05-01

    Full Text Available Temporal variations in the stable isotopic compositions of nitrate dissolved in stream water eluted from a cool-temperate forested watershed (8 ha were measured to quantify the biogeochemical effects of clear-cutting of trees and subsequent strip-cutting of the understory vegetation, dwarf bamboo (Sasa senanensis, with special emphasis on changes in the fate of atmospheric nitrate that had been deposited onto the watershed based on Δ17O values of nitrate. A significant increase in stream nitrate concentration to 15 μmol L−1 in spring of 2004 was correlated with a significant increase in the Δ17O values of nitrate. Additionally, the high Δ17O values of +14.3‰ suggest that the direct drainage of atmospheric nitrate accounted for more than 50% of total nitrate exported from the forested watershed. Similar increases in both concentrations and Δ17O values were also found in spring of 2005. Conversely, low Δ17O values less than +1.5‰ were observed in other seasons, regardless of increases in stream nitrate concentration, indicating that the majority of nitrate exported from the forested watershed during seasons other than spring was remineralized nitrate: those retained in the forested ecosystem as either organic-N or ammonium and then been converted to nitrate via microbial nitrification. When compared with the values prior to strip-cutting, the annual export of atmospheric nitrate and remineralized nitrate increased more than 16-fold and 4-fold, respectively, in 2004, and more than 13-fold and 5-fold, respectively, in 2005. The understory vegetation (Sasa was particularly important to enhancing biological consumption of atmospheric nitrate.

  17. Modelling crop root development and nitrate uptake

    OpenAIRE

    Pedersen, Anders

    2008-01-01

    Nitrate leaching from agricultural areas is a political and environmental issue at both local scale in Denmark and at global scale. Plant-available nitrogen and nitrate in the rooting zone in the growing season is necessary in order to obtain satisfactory crop yields. However, surplus nitrogen leads to a risk of nitrate losses through leaching and denitrification. In addition to artificial applications of nitrate, nitrate is produced by mineralisation processes in the soil from plant residues...

  18. Environmental Factors Affecting Ammonium Oxidation Under Iron Reducing Conditions

    Science.gov (United States)

    Jaffe, P. R.; Huang, S.; Ruiz-Urigüen, M.

    2014-12-01

    Ammonium (NH4+) oxidation coupled to iron (Fe) reduction in the absence of oxygen and nitrate/nitrite (NO3-/NO2-) has been reported by several investigators and referred to as Feammox. Feammox is a biological reaction, where Fe(III) is the electron acceptor, which is reduced to Fe(II), and NH4+ is the electron donor, which is oxidized to NO2-. Through a 180-day anaerobic incubation experiment, and using PCR-DGGE, 454-pyosequecing and qPCR analysis, we have shown that an Acidimicrobiaceae bacterium A6, a previously unreported species in the Acidimicrobiaceae family, might be either responsible or plays a key role in the Feammox process, We have enriched these Feammox bacteria (65.8% in terms of cell numbers) in a membrane reactor, and isolated the pure Acidimicrobiaceae bacterium A6 strain in an autotrophic medium. In samples collected and then incubated from a series of local wetland-, upland-, as well as storm-water detention pond-sediments, Feammox activity was only detected in acidic soil environments that contain Fe oxides. Using primers we developed for this purpose, Acidimicrobiaceae bacterium A6 was detected in all incubations where Feammox was observed. Anaerobic incubations of Feammox enrichment cultures adjusted to different pH, revealed that the optimal pH for Feammox is 4 ~ 5, and the reaction does not proceed when pH > 7. Feammox was still proceeding at pH as low as 2. In Feammox culture amended with different Fe(III) sources, Feammox reaction proceeded only when Fe oxides (ferrihydrite or goethite ) were supplied, whereas samples incubated with ferric chloride or ferric citrate showed no measurable NH4+ oxidation. Furthermore, we have also determined from incubation experiments conducted with a temperature gradient (10 ~ 35℃), that the Feammox process was active when the temperature is above 15℃, and the optimal temperature is 20℃. Incubations of enrichment culture with 79% Feammox bacteria appeared to remove circa 8% more NH4+ at 20ºC than at

  19. Impact of free ammonia on anammox rates (anoxic ammonium oxidation) in a moving bed biofilm reactor.

    Science.gov (United States)

    Jaroszynski, L W; Cicek, N; Sparling, R; Oleszkiewicz, J A

    2012-06-01

    Using a bench scale moving bed bioreactor (MBBR), the effect of free ammonia (FA, NH(3), the un-ionized form of ammonium NH(4)(+)) concentration on anoxic ammonium oxidation (anammox) was evaluated based on the volumetric nitrogen removal rate (NRR). Although, a detailed microbial analysis was not conducted, the major NRR observed was assumed to be by anammox, based on the nitrogen conversion ratios of nitrite to ammonium and nitrate to ammonium. Since the concentration of free ammonia as a proportion of the total ammonia concentration is pH-dependent, the impact of changing the operating pH from 6.9 to 8.2, was investigated under constant nitrogen loading conditions during continuous reactor operation. Furthermore, the effect of sudden nitrogen load changes was investigated under constant pH conditions. Batch tests were conducted to determine the immediate response of the anammox consortium to shifts in pH and FA concentrations. It was found that FA was inhibiting NRR at concentrations exceeding 2 mg N L(-1). In the pH range 7-8, the decrease in anammox activity was independent of pH and related only to the concentration of FA. Nitrite concentrations of up to 120 mg N L(-1) did not negatively affect NRR for up to 3.5 h. It was concluded that a stable NRR in a moving bed biofilm reactor depended on maintaining FA concentrations below 2 mg N L(-1) when the pH was maintained between 7 and 8. PMID:22483855

  20. Role of Anaerobic Ammonium Oxidation (Anammox) in Nitrogen Removal from a Freshwater Aquifer.

    Science.gov (United States)

    Smith, Richard L; Böhlke, J K; Song, Bongkeun; Tobias, Craig R

    2015-10-20

    Anaerobic ammonium oxidation (anammox) couples the oxidation of ammonium with the reduction of nitrite, producing N2. The presence and activity of anammox bacteria in groundwater were investigated at multiple locations in an aquifer variably affected by a large, wastewater-derived contaminant plume. Anammox bacteria were detected at all locations tested using 16S rRNA gene sequencing and quantification of hydrazine oxidoreductase (hzo) gene transcripts. Anammox and denitrification activities were quantified by in situ (15)NO2(-) tracer tests along anoxic flow paths in areas of varying ammonium, nitrate, and organic carbon abundances. Rates of denitrification and anammox were determined by quantifying changes in (28)N2, (29)N2, (30)N2, (15)NO3(-), (15)NO2(-), and (15)NH4(+) with groundwater travel time. Anammox was present and active in all areas tested, including where ammonium and dissolved organic carbon concentrations were low, but decreased in proportion to denitrification when acetate was added to increase available electron supply. Anammox contributed 39-90% of potential N2 production in this aquifer, with rates on the order of 10 nmol N2-N L(-1) day(-1). Although rates of both anammox and denitrification during the tracer tests were low, they were sufficient to reduce inorganic nitrogen concentrations substantially during the overall groundwater residence times in the aquifer. These results demonstrate that anammox activity in groundwater can rival that of denitrification and may need to be considered when assessing nitrogen mass transport and permanent loss of fixed nitrogen in aquifers. PMID:26401911

  1. 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

  2. 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.

  3. Assessment of anthropogenic nitrate pollution in groundwater in northeast Cairo using nitrogen-15 technique

    International Nuclear Information System (INIS)

    Groundwater contamination of elevated nitrate ions was investigated in a limited area of the north-eastern part of Cairo (EI-Gabal EI-Asfar farm and its surroundings). Stable isotope techniques of nitrogen (δ15N), oxygen (δ18O), and hydrogen (δ2H) with major ions and trace elements analyses followed by data evaluation were combined to assess the potential sources and fate of nitrate contamination. In the studied area, the unconfined aquifer system is found to be vulnerable to nitrate impacts from land uses because of the sandy, permeable soils and a relatively shallow depth to groundwater. Several potential sources of elevated nitrate exist including a rapid infiltration of sewage effluents, used for irrigation, soil organic and inorganic nitrogen, and land application of animal wastes (manure), sludge, and inorganic chemical fertilizers. Surface and ground water samples as well as surface soil samples were collected beside the principal nitrate sources that are likely to affect groundwater quality. Data revealed that surface and groundwater samples have high TDS, nitrate, phosphate, and trace elements contents especially at the north-eastern pad and at the southern part of the studied area. Soil samples show relative enrichment in trace elements and total nitrogen contents due to prolonging sewage water irrigation especially at EI-Gabal EI-Asfar farm and at the northern part of the studied area. Results of δ18O and δ2H for most of groundwater samples mainly reflect more enriched values than that of Nile River due to recycling of water used for irrigation. The δ15N values of nitrate in water samples indicate that the source yielding lower nitrate concentrations could be commercial fertilizers or nitrifying soil organic nitrogen which is more pronounced at the western part. In the north-eastern part other sources being responsible for the higher nitrate concentrations appears to be mixing with sewage or manure and ammonium phosphate fertilizer. This mixing

  4. Investigation of disposal of nitrate-bearing effluent from in-situ leaching process by natural evaporation in Yining uranium mine

    International Nuclear Information System (INIS)

    Experiments indicated, after lime neutralization and precipitation of nitrate-bearing effluent from in-situ leaching process, uranium concentration increase with the increasing of nitrate concentration. Only when nitrate concentration is <0.5 mg/L, uranium concentration can drop from 1.5-2.0 mg/L to about 1.0 mg/L. The permeability coefficient of soil is about 1.0-1.1 m/d in the place which is scheduled for building natural evaporation pool. After lime neutralization of nitrate-bearing effluent, it can drop to 0.03-0.01 m/d. Setting up water-proof layer in natural evaporation pool can reduce pollution of underground water by uranium, nitrate and ammonium

  5. Proton dynamics investigation for dimethyl ammonium cation

    International Nuclear Information System (INIS)

    Proton dynamics in dimethyl ammonium cation has been investigated by means of NMR and spin echo methods in polycrystalline salts [NH2(CH3)2]+Bi2J9- and [NH2(CH3)2]+SbJ9-. Spin-lattice relaxation time as well as second moment of NMR line have been measured for influence study of crystal structure changes on proton dynamics

  6. 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.

  7. DETECTION OF THE AMMONIUM ION IN SPACE

    Energy Technology Data Exchange (ETDEWEB)

    Cernicharo, J.; Tercero, B. [Deparment of Astrophysics, CAB, INTA-CSIC, Crta Torrejon-Ajalvir Km 4, E-28850 Torrejon de Ardoz, Madrid (Spain); Fuente, A. [Observatorio Astronomico Nacional, Apdo. 112, E-28803 Alcala de Henares (Spain); Domenech, J. L.; Cueto, M.; Carrasco, E.; Herrero, V. J.; Tanarro, I. [Instituto de Estructura de la Materia, IEM-CSIC, Serrano 123, E-28006 Madrid (Spain); Marcelino, N. [NRAO, 520 Edgemont Road, Charlottesville, VA 22902 (United States); Roueff, E. [Luth, Observatoire de Paris, CNRS UMR8102, Place J. Janssen F-92190 Meudon (France); Gerin, M. [LERMA, Observatoire de Paris, CNRS UMR8112 and Ecole Normale Superieure, 61 Avenue de lObservatoire, F-75014 Paris (France); Pearson, J., E-mail: jcernicharo@cab.inta-csic.es [Jet Propulsion Laboratory, 4800 Oak Grove Drive, MC 168-314, Pasadena, CA 91109 (United States)

    2013-07-01

    We report on the detection of a narrow feature at 262816.73 MHz toward Orion and the cold prestellar core B1-bS which we attribute to the 1{sub 0}-0{sub 0} line of the deuterated ammonium ion, NH{sub 3}D{sup +}. The observations were performed with the IRAM 30 m radio telescope. The carrier has to be a light molecular species as it is the only feature detected over 3.6 GHz of bandwidth. The hyperfine structure is not resolved, indicating a very low value for the electric quadrupolar coupling constant of nitrogen which is expected for NH{sub 3}D{sup +} as the electric field over the N nucleus is practically zero. Moreover, the feature is right at the predicted frequency for the 1{sub 0}-0{sub 0} transition of the ammonium ion, 262817 {+-} 6 MHz (3{sigma}), using rotational constants derived from new infrared data obtained in our laboratory in Madrid. The estimated column density is (1.1 {+-} 0.2) Multiplication-Sign 10{sup 12} cm{sup -2}. Assuming a deuterium enhancement similar to that of NH{sub 2}D, we derive N(NH{sub 4}{sup +}) {approx_equal} 2.6 Multiplication-Sign 10{sup 13} cm{sup -2}, i.e., an abundance for ammonium of a few 10{sup -11}.

  8. Effect of ammonium hydroxide on preparation process of YBa2Cu3O7-x superconductor by sol gel method

    International Nuclear Information System (INIS)

    In this paper the effect of ammonium hydroxide addition to the solution of metallic oxide on sol gel preparation process of YBa2Cu3O7-x is studied with differential thermal analysis, thermal graviometry and X-ray diffraction. Two samples with and without ammonium hydroxide. Ammonium hydroxide prevents both barium nitrate precipitate during the gel preparation and also unwanted reaction as well as increasing homogeneous product. After drying the gel, the samples heated up to 1050digC in DTA apparatus in order to find more accurate the type and the temperature of reaction during the reparation process. After the initial reactions in the samples, Y2Cu2O5 and 123 phases are created in the range of 780-840digC and then the 123 phase is strengthened at 900-950digC. As shown in X-ray data, 123 was the only phase after this range. In addition ammonium hydroxide support and increase the creation of 123 phase at lower temperature

  9. Effect of ammonium hydroxide on preparation process of YBa2Cu3O7-x superconductor by sol gel method

    Directory of Open Access Journals (Sweden)

    H Arabi

    2006-09-01

    Full Text Available  In this paper the effect of ammonium hydroxide addition to the solution of metallic oxide on sol gel preparation process of YBCO is studied with differential thermal analysis, thermal graviometry and X-ray diffraction. Two samples with and without ammonium hydroxide. Ammonium hydroxide prevents both barium nitrate precipitate during the gel preparation and also unwanted reaction as well as increasing homogeneous product. After drying the gel, the samples heated up to 1050°C in DTA apparatus in order to find more accurate the type and the temperature of reaction during the preparation process. After the initial reactions in the samples, Y2Cu2O5 and 123 phases are created in the range of 780-840°C and then the 123 phase is strengthened at 900-950°C. As shown in X-ray data, 123 was the only phase after this range. In addition ammonium hydroxide support and increase the creation of 123 phase at lower temperature.

  10. Influence of surfactants on the properties of precipitates of difficulty soluble actinide and lanthanide compounds. 1. Ammonium diuranate

    International Nuclear Information System (INIS)

    The main characteristics have been ascertained of the influence of various kinds of surfactants on the properties of a precipitate of ammonium diuranate thrown down by a concentrated ammonia solution from a nitric acid solution of uranyl nitrate. It has been shown that monomolecular cationogenic surfactants have no effect on the properties of the precipitate. Nonionogenic and anionogenic monomolecular surfactants promote an increase of the rate of sedimentation of ammonium diuranate. High-molecular-weight cationogenic surfactants have a negative effect on the rates of sedimentation and filtration of a suspension, and increase the moisture content of a precipitate. The action of high-molecular-weight nonionogenic surfactants is analogous to that of monomolecular surfactants of the same type. It has been shown that the most effective flocculants of ammonium diuranate are anionogenic polyelectrolytes. Low concentrations of these substances in a suspension enable the rates of sedimentation and filtration to be increased and the moisture content of an ammonium diuranate precipitate to be reduced owing to formation of stable flakes possessing elasticity

  11. Woodchip-sulfur based heterotrophic and autotrophic denitrification (WSHAD) process for nitrate contaminated water remediation.

    Science.gov (United States)

    Li, Rui; Feng, Chuanping; Hu, Weiwu; Xi, Beidou; Chen, Nan; Zhao, Baowei; Liu, Ying; Hao, Chunbo; Pu, Jiaoyang

    2016-02-01

    Nitrate contaminated water can be effectively treated by simultaneous heterotrophic and autotrophic denitrification (HAD). In the present study, woodchips and elemental sulfur were used as co-electron donors for HAD. It was found that ammonium salts could enhance the denitrifying activity of the Thiobacillus bacteria, which utilize the ammonium that is produced by the dissimilatory nitrate reduction to ammonium (DNRA) in the woodchip-sulfur based heterotrophic and autotrophic denitrification (WSHAD) process. The denitrification performance of the WSHAD process (reaction constants range from 0.05485 h(-1) to 0.06637 h(-1)) is better than that of sulfur-based autotrophic denitrification (reaction constants range from 0.01029 h(-1) to 0.01379 h(-1)), and the optimized ratio of woodchips to sulfur is 1:1 (w/w). No sulfate accumulation is observed in the WSHAD process and the alkalinity generated in the heterotrophic denitrification can compensate for alkalinity consumption by the sulfur-based autotrophic denitrification. The symbiotic relationship between the autotrophic and the heterotrophic denitrification processes play a vital role in the mixotrophic environment. PMID:26650451

  12. The effect of different carbon sources on reduction of nitrate in effluent from the mining industry : Olika kolkällors inverkan på reduktion av nitrat i processvatten från gruvindustrin

    OpenAIRE

    Lindberg, Hanna

    2014-01-01

    Mine water effluent contains high levels of nitrogen due to residues from undetonated ammonium- nitrate based explosives. Excess nitrogen in aquatic ecosystems can cause eutrophication. Within a mining area, tailings and clarification ponds have the potential to reduce nitrogen levels by biological uptake of nitrogen into growing algae and denitrification in pond sediments. A previous study at the LKAB Kiruna mine investigated the potential nitrogen removal within the tailings and clarificati...

  13. Identification and functional analysis of a nitrate assimilation operon nasACKBDEF from Amycolatopsis mediterranei U32.

    Science.gov (United States)

    Shao, Zhihui; Gao, Jin; Ding, Xiaoming; Wang, Jin; Chiao, Juishen; Zhao, Guoping

    2011-07-01

    Nitrate assimilation has been well studied for Gram-negative bacteria but not so much in the Gram-positive actinomycetes up to date. In a rifamycin SV-producing actinomycete, Amycolatopsis mediterranei strain U32, nitrate not only can be used as a sole nitrogen source but also remarkably stimulates the antibiotic production along with regulating the related metabolic enzymes. A gene cluster of nasACKBDEF was cloned from a U32 genomic library by in situ hybridization screening with a heterogeneous nasB probe and confirmed later by whole genome sequence, corresponding to the protein coding genes of AMED_1121 to AMED_1127. These genes were co-transcribed as an operon, concomitantly repressed by ammonium while activated with supplement of either nitrate or nitrite. Genetic and biochemical analyses identified the essential nitrate/nitrite assimilation functions of the encoded proteins, orderly, the assimilatory nitrate reductase catalytic subunit (NasA), nitrate reductase electron transfer subunit (NasC), nitrate/nitrite transporter (NasK), assimilatory nitrite reductase large subunit (NasB) and small subunit (NasD), bifunctional uroporphyrinogen-III synthase (NasE), and an unknown function protein (NasF). Comparing rifamycin SV production and the level of transcription of nasB and rifE from U32 and its individual nas mutants in Bennet medium with or without nitrate indicated that nitrate assimilation function encoded by the nas operon played an essential role in the "nitrate stimulated" rifamycin production but had no effect upon the transcription regulation of the primary and secondary metabolic genes related to rifamycin biosynthesis. PMID:21424691

  14. Researches concerning nitrates and nitrites accumulation in kohlrabi in the west side of Romania

    Directory of Open Access Journals (Sweden)

    Monica NEGREA

    2009-05-01

    Full Text Available In this study we followed the monitoring of nitrate and nitrite content in kohlrabi after the administration of organic and mineral fertilizers in different doses. Kohlrabi samples (GIGANT hybride for the analysis have been taken from an experimental field established in Mosnita, near Timisoara. In the experimental field to kohlrabi have been administrated three doses of synthetic fertilisers NPK N0P0K0 N30P30K30, (200 kg/ha NPK N60P60K60 (400 kg/ha NPK and N120P60K60 (400 kg/ha NPK + 180 kg/ha ammonium nitrogen and one dose of organic fertilisers (organic compost - 30 t/ha.The nitrate and nitrite content in kohlrabi was done from aqueous solution after spectrophotometric detection using the rapid tests AQUA MERCK and the Spectrophotometer SQ 118 at a wavelength of 515 and 525 nm for nitrate and nitrites. The experimental results show that the nitrate content, in samples taken from the Timis County we registered values above maximum limit allowed for kohlrabi. The highest nitrate content (2180 ppm was registered to variant V4 where the used mineral fertiliser dose was N120P60K60. This excessive accumulation appears because of the high nitrogen content N120 applied to this variant.

  15. Complete genome sequence of Nitrosomonas sp. Is79, an ammonia oxidizing bacterium adapted to low ammonium concentrations

    Energy Technology Data Exchange (ETDEWEB)

    Bollmann, Annette [Miami University, Oxford, OH; Sedlacek, Christopher J [Miami University, Oxford, OH; Laanbroek, Hendrikus J [Netherlands Institute of Ecology (NIOO-KNAW); Suwa, Yuichi [Chuo University, Tokyo, Japan; Stein, Lisa Y [University of California, Riverside; Klotz, Martin G [University of Louisville, Louisville; Arp, D J [Oregon State University; Sayavedra-Soto, LA [Oregon State University; Lu, Megan [Los Alamos National Laboratory (LANL); Bruce, David [Los Alamos National Laboratory (LANL); Detter, J. Chris [U.S. Department of Energy, Joint Genome Institute; Tapia, Roxanne [Los Alamos National Laboratory (LANL); Han, James [U.S. Department of Energy, Joint Genome Institute; Woyke, Tanja [U.S. Department of Energy, Joint Genome Institute; Lucas, Susan [U.S. Department of Energy, Joint Genome Institute; Pitluck, Sam [U.S. Department of Energy, Joint Genome Institute; Pennacchio, Len [U.S. Department of Energy, Joint Genome Institute; Nolan, Matt [U.S. Department of Energy, Joint Genome Institute; Land, Miriam L [ORNL; Huntemann, Marcel [U.S. Department of Energy, Joint Genome Institute; Deshpande, Shweta [U.S. Department of Energy, Joint Genome Institute; Han, Cliff [Los Alamos National Laboratory (LANL); Chen, Amy [U.S. Department of Energy, Joint Genome Institute; Kyrpides, Nikos C [U.S. Department of Energy, Joint Genome Institute; Mavromatis, K [U.S. Department of Energy, Joint Genome Institute; Markowitz, Victor [U.S. Department of Energy, Joint Genome Institute; Szeto, Ernest [U.S. Department of Energy, Joint Genome Institute; Ivanova, N [U.S. Department of Energy, Joint Genome Institute; Mikhailova, Natalia [U.S. Department of Energy, Joint Genome Institute; Pagani, Ioanna [U.S. Department of Energy, Joint Genome Institute; Pati, Amrita [U.S. Department of Energy, Joint Genome Institute; Peters, Lin [U.S. Department of Energy, Joint Genome Institute; Ovchinnikova, Galina [U.S. Department of Energy, Joint Genome Institute; Goodwin, Lynne A. [Los Alamos National Laboratory (LANL)

    2013-01-01

    Nitrosomonas sp. Is79 is a chemolithoautotrophic ammonia-oxidizing bacterium that belongs to the family Nitrosomonadaceae within the phylum Proteobacteria. Ammonia oxidation is the first step of nitrification, an important process in the global nitrogen cycle ultimately resulting in the production of nitrate. Nitrosomonas sp. Is79 is an ammonia oxidizer of high interest because it is adapted to low ammonium and can be found in freshwater environments around the world. The 3,783,444-bp chromosome with a total of 3,553 protein coding genes and 44 RNA genes was sequenced by the DOE-Joint Genome Institute Program CSP 2006.

  16. Assessment of the synthesis routes conditions for obtaining ammonium dinitramide by the FT-IR

    Directory of Open Access Journals (Sweden)

    José Irineu Sampaio de Oliveira

    2011-09-01

    Full Text Available Over the last two decades, many routes have been proposed to synthesize ammonium dinitramide (ADN. However, most of them lie in routes in which reactants are too expensive for large-scale production. In this sense, the use of ordinary reactants is of paramount importance in this case. The aim in this synthesis consists on nitrating a starting reactant in a reaction known as nitration. Both the nitrating agent and the starting reactant should preferably be ordinary, narrowing the possibility of having realistic options for them. The most ordinary nitrating agent consists of a mixture of sulfuric and fuming nitric acids. Therefore, the breakthrough must come from the suitable choice of the starting reactant. However, so far, the only viable reaction relies on the use of sulfamate salts. Even though the process with this kind of salt has been largely commercially developed, only few information are available in the literature to properly address issues emerged from it. In this study, an attempt is made to enlighten some effects on the product caused by modifications in the route conditions. Characterization of the resulting products was confirmed by FT-IR in the region of MIR and NIR. The characteristic bands employed to identify ADN in the region of middle infrared were: 3129 and 1384 cm-1 (NH4+; 1537, 1344, 1209, and 1177 cm-1 (NO2; 1032, 954 cm-1 (N3; 828, 762 and 732 cm-1(NO2. The near infrared analysis pointed out few bands at 5185 and 4672 cm-1 in NH combination bands region. The resulting middle infrared spectrum was compared to the reference found in the literature for this product. The results show excellent agreement with the expected product.

  17. Identification of groundwater nitrate sources in pre-alpine catchments: a multi-tracer approach

    Science.gov (United States)

    Stoewer, Myriam; Stumpp, Christine

    2014-05-01

    Porous aquifers in pre-alpine areas are often used as drinking water resources due to their good water quality status and water yield. Maintaining these resources requires knowledge about possible sources of pollutants and a sustainable management practice in groundwater catchment areas. Of particular interest in agricultural areas, like in pre-alpine regions, is limiting nitrate input as main groundwater pollutant. Therefore, the objective of the presented study is i) to identify main nitrate sources in a pre-alpine groundwater catchment with current low nitrate concentration using stable isotopes of nitrate (d18O and d15N) and ii) to investigate seasonal dynamics of nitrogen compounds. The groundwater catchment areas of four porous aquifers are located in Southern Germany. Most of the land use is organic grassland farming as well as forestry and residential area. Thus, potential sources of nitrate mainly are mineral fertilizer, manure/slurry, leaking sewage system and atmospheric deposition of nitrogen compounds. Monthly freshwater samples (precipitation, river water and groundwater) are analysed for stable isotope of water (d2H, d18O), the concentration of major anions and cations, electrical conductivity, water temperature, pH and oxygen. In addition, isotopic analysis of d18O-NO3- and d15N-NO3- for selected samples is carried out using the denitrifier method. In general, all groundwater samples were oxic (10.0±2.6mg/L) and nitrate concentrations were low (0.2 - 14.6mg/L). The observed nitrate isotope values in the observation area compared to values from local precipitation, sewage, manure and mineral fertilizer as well as to data from literature shows that the nitrate in freshwater samples is of microbial origin. Nitrate derived from ammonium in fertilizers and precipitation as well as from soil nitrogen. It is suggested that a major potential threat to the groundwater quality is ammonia and ammonium at a constant level mainly from agriculture activities as

  18. A biological source of oceanic alkyl nitrates

    Science.gov (United States)

    Dahl, E. E.; Lewis, C. B.; Velasco, F. L.; Escobar, C.; Kellogg, D.; Velcamp, M.

    2013-12-01

    Alkyl nitrates are an important component of reactive nitrogen in the troposphere. The oceans are a source of alkyl nitrates to the atmosphere, however the source of alkyl nitrates in the oceans is unknown. It has been demonstrated that the reaction of alkyl peroxy radicals (ROO) with nitric oxide (NO) produces alkyl nitrates in the aqueous phase. We hypothesize that alkyl nitrates may be formed by organisms through the same reaction and therefore biological production could be a source of alkyl nitrates to the troposphere. This work focuses on the production of alkyl nitrates by the diatoms Chaetoceros muelleri and Thalassiosira weisfloggi. Using chemostats, we measure alkyl nitrates formed under nitrate limited conditions. We also use triggers and inhibitors of nitric oxide formation to determine if alkyl nitrate formation is affected by changes in NO production. To date, the rates of production of alkyl nitrates in our cultures, lead us to estimate a production rate on the order of femtomolar/day for C1-C3 alkyl nitrates by diatom species in the equatorial Pacific Ocean. This suggests that diatoms may contribute to the overall ocean source of alkyl nitrates; however, it is possible that other types of phytoplankton, such as cyanobacteria, that are more abundant in the open ocean, may contribute to a greater extent.

  19. Review:Anaerobic ammonium oxidation for treatment of ammonium-rich wastewaters

    Institute of Scientific and Technical Information of China (English)

    Lei ZHANG; Ping ZHENG; Chongojian TANG; Ren-cun JIN

    2008-01-01

    The concept of anaerobic ammonium oxidation (ANAMMOX) is presently of great interest.The functional bacteria belonging to the Planctomycete phylum and their metabolism are investigated by microbiologists.Meanwhile,the ANAMMOX is equally valuable in treatment of ammonium-rich wastewaters.Related processes including partial nitritation-ANAMMOX and completely autotrophic nitrogen removal over nitrite (CANON) have been developed,and lab-scale experiments proved that both processes were quite feasible in engineering with appropriate control.Successful full-scale practice in the Netherlands will ac-celerate application of the process in future.This review introduces the microbiology and more focuses on application of the ANAMMOX process.

  20. Nitrate metabolism in tobacco leaves overexpressing Arabidopsis nitrite reductase.

    Science.gov (United States)

    Davenport, Susie; Le Lay, Pascaline; Sanchez-Tamburrrino, Juan Pablo

    2015-12-01

    Primary nitrogen assimilation in plants includes the reduction of nitrite to ammonium in the chloroplasts by the enzyme nitrite reductase (NiR EC:1.7.7.1) or in the plastids of non-photosynthetic organs. Here we report on a study overexpressing the Arabidopsis thaliana NiR (AtNiR) gene in tobacco plants under the control of a constitutive promoter (CERV - Carnation Etched Ring Virus). The aim was to overexpress AtNiR in an attempt to alter the level of residual nitrite in the leaf which can act as precursor to the formation of nitrosamines. The impact of increasing the activity of AtNiR produced an increase in leaf protein and a stay-green phenotype in the primary transformed AtNiR population. Investigation of the T1 homozygous population demonstrated elevated nitrate reductase (NR) activity, reductions in leaf nitrite and nitrate and the amino acids proline, glutamine and glutamate. Chlorophyl content of the transgenic lines was increased, as evidenced by the stay-green phenotype. This reveals the importance of NiR in primary nitrogen assimilation and how modification of this key enzyme affects both the nitrogen and carbon metabolism of tobacco plants. PMID:26447683

  1. Nitrate metabolism in the gromiid microbial universe

    DEFF Research Database (Denmark)

    Høgslund, Signe; Risgaard-Petersen, Nils; Cedhagen, Tomas

    Eukaryotic nitrate respiration supported by intracellular nitrate storages contributes substantially to the nitrogen cycle. Research focus is currently directed towards two phyla: Foraminifera and diatoms, but the widespread Gromia in the Rhizaria may be another key organism. These giant protists...

  2. Metal nitrate conversion method, patent application

    NARCIS (Netherlands)

    2008-01-01

    A method for converting a supported metal nitrate into the corresponding supported metal comprises heating the metal nitrate to effect its decomposition under a gas mixture that contains nitric oxide and has an oxygen content of

  3. Artefacts in the sampling of nitrate studied in the "INTERCOMP" campaigns of EUROTRAC-AEROSOL

    Science.gov (United States)

    Schaap, M.; Spindler, G.; Schulz, M.; Acker, K.; Maenhaut, W.; Berner, A.; Wieprecht, W.; Streit, N.; Müller, K.; Brüggemann, E.; Chi, X.; Putaud, J.-P.; Hitzenberger, R.; Puxbaum, H.; Baltensperger, U.; ten Brink, H.

    Sampling of aerosol-nitrate can be problematic because of evaporative loss of the semi-volatile ammonium nitrate or adsorption of nitric acid gas. Such artefacts, which depend on filter type and ambient conditions, are not well documented for the filters in use in Europe and this was the reason to study these in a series of intercomparison trials. The trials were performed within the "INTERCOMP" programme of the AEROSOL subproject of EUROTRAC-2. The major effort was a 2-week field campaign at the rural site of Melpitz, a village near Leipzig in eastern Germany (INTERCOMP2000). Samplers were used containing the most common filter types in use in Europe, i.e. quartz, Teflon, (mixed) cellulose ester and cellulose. The concentration of nitrate in PM2.5, mainly present as ammonium nitrate, was on average 3.3 μg m -3. The variability in the concentrations stemming from the samplers appeared to be rather constant: ± 0.5 μg m -3 from the average of all samplers. The reason for the constant (but random) variability remains unexplained. Thus, the concentrations stemming from the samplers agreed very well at the average level with relative differences of 15% and less for higher concentrations. This is evidence that the influence of the mentioned artefacts was negligible. The absence is explained by extrapolation of results of tests on the artefacts in a laboratory setting (INTERCOMP99). It was found there that the loss of ammonium nitrate from Teflon and quartz filters is only substantial when temperatures are much higher than those during the field campaign. Cellulose and cellulose-acetate filters quantitatively collected both ammonium nitrate and nitric acid in the laboratory study, but in Melpitz measured nitric acid concentrations were too low to identify its adsorption. Possible artefacts due to adsorption of nitrous acid were negligible. We also used the laboratory information to evaluate the results of a further intercomparison (INTERCOMP98) in the Po

  4. A Novel Chemical Nitrate Destruction Process

    Energy Technology Data Exchange (ETDEWEB)

    Dziewinski, J.; Marczak, S.

    1999-03-01

    Nitrates represent one of the most significant pollutant discharged to the Baltic Sea by the Sliiamae hydrometallurgical plant. This article contains a brief overview of the existing nitrate destruction technologies followed by the description of a new process developed by the authors. The new chemical process for nitrate destruction is cost effective and simple to operate. It converts the nitrate to nitrogen gas which goes to the atmosphere.

  5. Studies on the preparation and characterisation of ammonium uranyl carbonate (AUC)

    International Nuclear Information System (INIS)

    Studies have been carried out in the laboratory on the preparation of ammonium uranyl carbonate (AUC), using concentrated solution of uranyl nitrate. The precipitation of AUC has been done by addition of (NH4)2CO3 solution and injecting gaseous ammonia and carbon dioxide. The precipitates obtained under varying parameter have been characterised by chemical and XRD analysis and the precipitate obtained under ideal conditions have been found to have the formula [(NH4)4UO2(CO3)3]. Though the studies were mainly aimed at standardising the procedures for the identification of precipitates, some of the AUC samples have been tested to see their suitability for conversion to ceramic grade UO2 powder and its pelletisation and sintering properties of the pellets. The data collected during these studies is presented. (author). 15 refs., 3 figs., 2 tabs

  6. Modeling nitrate removal in a denitrification bed

    Science.gov (United States)

    Denitrification beds are being promoted to reduce nitrate concentrations in agricultural drainage water to alleviate the adverse environmental effects associated with nitrate pollution in surface water. In this system, water flows through a trench filled with a carbon media where nitrate is transfor...

  7. 21 CFR 172.160 - Potassium nitrate.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 3 2010-04-01 2009-04-01 true Potassium nitrate. 172.160 Section 172.160 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) FOOD FOR HUMAN... Preservatives § 172.160 Potassium nitrate. The food additive potassium nitrate may be safely used as a...

  8. Tracing industrial ammonium in atmospheric deposition in the Athabasca Oil Sands Region, Alberta, Canada

    Science.gov (United States)

    Mayer, B.; Proemse, B. C.; Fenn, M. E.

    2013-12-01

    The expanding industrial development in the Athabasca oil sands region (AOSR) in northeastern Alberta, Canada, has raised concerns about increasing nitrogen (N) emissions from oil sands operations and their potential effects on the surrounding terrestrial and aquatic ecosystems. Stable isotope techniques may help to trace industrial emissions provided that they are isotopically distinct from background isotope ratios of atmospheric N compounds. Ammonium deposition rates (NH4-N) typically exceed nitrate deposition rates (NO3-N) in the AOSR (Proemse et al., 2013), suggesting that emissions of reduced nitrogen compounds play a significant role for the atmospheric nitrogen budget in the AOSR. We collected atmospheric ammonium in open field bulk deposition and throughfall using ion exchange resins over ~6 months time periods from summer 2007 to summer 2011 located at distances between 3 to 113 km to one of the major oil sands developments in the AOSR. Ammonium deposition rates and δ15N-NH4 values were determined using ion chromatography and the ammonium diffusion method (Sebilo et al., 2004) on resin extracts. Atmospheric ammonium deposition rates in open field bulk collectors and throughfall collectors ranged from 1.0 to 4.7 kg ha-1 yr-1 NH4-N, and from 1.0 to 18.3 kg ha-1 yr-1 NH4-N, respectively. δ15N-NH4 values varied from -6.3 to +14.8‰ with the highest δ15N values typically associated with elevated NH4-N deposition rates. δ15N-NH4 values of up to +20.1‰ were observed for industrially emitted NH4 in particulate matter (PM2.5) emissions (Proemse et al., 2012) suggesting that industrial NH3 and NH4 emissions are associated with elevated δ15N values providing a potential tracer. Applying a two-end-member mixing analysis using a background δ15N-NH4 value of -3.6‰ for summer and -3.2‰ for winter periods revealed that particularly sites within ~30 km radius from the main oil sands developments are significantly affected by industrial contributions to

  9. Mass spectrometric determination of /sup 15/N contents of nitrates in polluted soils at Kasur area

    International Nuclear Information System (INIS)

    This study was carried out for the assessment of pollutants effect on soil profiles. Three sampling sites were selected in Kasur area, two in the vicinity of a pond which collects industrial / domestic waste water (polluted soil profiles) and the third at two kilometers away from the pond (non polluted soil profile) near the agricultural piece of land. Samples were collected from each profile in the interval of 50 cm depth up to wet sand. Bremmer and keeney method was adopted for the extraction of nitrate nitrogen from soil and its conversion to ammonium ions. Ammonium concentrates were converted to nitrogen gas using potassium hypo bromide solution and analyzer on GD-150 mass spectrometer. Mean values of N/sup 15/ of each profile is given. (orig./A.B.)

  10. Nitrate Uptake, Nitrate Reductase Distribution and their Relation to Proton Release in Five Nodulated Grain Legumes

    OpenAIRE

    Fan, X. H.; Tang, C; RENGEL, Z.

    2002-01-01

    Nitrate uptake, nitrate reductase activity (NRA) and net proton release were compared in five grain legumes grown at 0·2 and 2 mm nitrate in nutrient solution. Nitrate treatments, imposed on 22‐d‐old, fully nodulated plants, lasted for 21 d. Increasing nitrate supply did not significantly influence the growth of any of the species during the treatment, but yellow lupin (Lupinus luteus) had a higher growth rate than the other species examined. At 0·2 mm nitrate supply, nitrate uptake rates ran...

  11. High temperature interaction studies on equimolar nitrate mixture of uranyl nitrate hexahydrate and gadolinium nitrate hexahydrate

    International Nuclear Information System (INIS)

    Rare earths including gadolinium form a sizeable fraction of the fission products in the nuclear fission of fissile material in the reactor. These fission products can interact with uranium dioxide fuel and can form various compounds which can alter the thermal behavior of the fuel. The mixed oxide formed due to the high temperature interactions of mixture of uranyl nitrate hexahydrate (UNH) and gadolinium nitrate hexahydrate (GdNH) has been studied using thermal and X- ray diffraction techniques. The equimolar mixture of UNH and GdNH was prepared by mixing the weighed amount of individual nitrates and grinding gently with mortar and pestle. Thermogravimetry (TG) measurements were carried out by separately heating 100 mg of mixture and individual nitrates at heating rate of 10°C min-1 using Netzsch thermal analyzer (Model No.: STA 409 PC Luxx) in high purity nitrogen atmosphere with a flow rate of 120 mL min-1. The XRD measurement was carried out on a Philips X-ray diffractometer (Model PW1710) using nickel-filtered Cu-Kα radiation

  12. Quaternary Ammonium Polyethyleneimine: Antibacterial Activity Ira

    International Nuclear Information System (INIS)

    Quaternary ammonium polyethyleneimine- (QA-PEI-) based nanoparticles were synthesized using two synthetic methods, reductive amination and N-alkylation. According to the first method, QA-PEI nanoparticles were synthesized by cross-linking with glutaraldehyde followed by reductive amination with octanal and further N-methylation with methyl iodide. The second method is based on crosslinking with dialkyl halide followed by N-alkylation with octyl halide and further N-methylation with methyl iodide. QA-PEI nanoparticles completely inhibited bacterial growth (>106 bacteria), including both Gram-positive, that is, Staphylococcus aureus at 80 μ/mL, and Gram-negative, that is, Escherichia coli at 320 μ/mL. Activity analysis revealed that the degree of alkylation and N-methylation of the QA-PEI nanoparticles plays a significant role in antibacterial activity of the reagent. The most potent compound was octyl alkylated QA-PEI alkylated at 1 : 1 mole ratio (primary amine of PEI monomer units/alkylating agent). Also, cytotoxicity studies on MAT-LyLu and MBT cell lines were performed with QA-PEI nanoparticles. These findings confirm previous reports that poly cations bearing quaternary ammonium moieties inhibit bacterial growth in vitro and have a potential use as additives in medical devices which need antibacterial properties.

  13. Identification of the nitrate contamination sources of the Brusselian sands groundwater body (Belgium) using a dual-isotope approach

    Science.gov (United States)

    Mattern, Samuel; Vanclooster, Marnik

    2010-05-01

    Knowledge of the groundwater pollution source is of primary importance to define appropriate remediation strategies. Yet, the identification of the contamination sources remains a complicated task. A dual isotope approach has been used to provide information for tracing sources of nitrate in water. In this study, we used the naturally occurring stable isotopic composition of groundwater nitrate (1) to evaluate the origin of nitrate in the Brussels sands aquifer (Belgium) and (2) to study the temporal dynamics of the isotope signature of groundwater nitrate in this region. Potential N sources sampled in the region, including e.g. ammonium and nitrate mineral fertilizers, sewage and rain, had isotopic signatures that fell within the corresponding typical ranges found in literature. Some of them however deviated from the isotopic ranges corresponding to typical N sources, illustrating the impact of processes affecting the isotopic signature of the nitrate sources. During a pluri-annual sampling campaign, groundwater samples were collected at 10 moments between June 2007 and February of 2009 over 9 monitoring stations located in the western part of the study area. The isotopic data time series suggest that, most of the time, N applied on the soil has been cycled in the soil by micro-organisms before leaching to the groundwater, while the isotopic data and the high nitrate concentrations strongly suggests that nitrate of the groundwater sampled in January 2008 principally originates from mineral fertilizers. The isotopic data measured at some of the 114 monitoring stations across the study area strongly suggests that the sources of nitrate are mineral fertilizers used in agriculture and golf courses, manure leaching from unprotected stockpiles in farms, domestic gardening practices, cesspools and probably cemeteries. Isotopic data are particularly helpful when associated with other information like historical data about monitoring stations, land use, chemical parameters

  14. Nitration of naphthalene and remarks on the mechanism of electrophilic aromatic nitration*

    OpenAIRE

    Olah, George A.; Narang, Subhash C.; Olah, Judith A.

    1981-01-01

    Naphthalene was nitrated with a variety of nitrating agents. Comparison of data with Perrin's electrochemical nitration [Perrin, C. L. (1977) J. Am. Chem. Soc. 99, 5516-5518] shows that nitration of naphthalene gives an α-nitronaphthalene to β-nitronaphthalene ratio that varies between 9 and 29 and is thus not constant. Perrin's data, therefore, are considered to be inconclusive evidence for the proposed one-electron transfer mechanism for the nitration of naphthalene and other reactive aroma...

  15. [Review of dual stable isotope technique for nitrate source identification in surface- and groundwater in China].

    Science.gov (United States)

    Xu, Zhi-Wei; Zhang, Xin-Yu; Yu, Gui-Rui; Sun, Xiao-Min; Wen, Xue-Fa

    2014-08-01

    Water nitrate (NO3-) contamination is a world-wide environmental problem under the effects of intensive human activities. Sources identification of NO3- contamination in water is important for better management of water quality. Dual stable isotope data of nitrate nitrogen (delta15N) and nitrate oxygen (delta18O) combined with other stable isotopes and chemical analysis data have been frequently used to identify NO3- sources, differentiate percentage of the different NO3- sources and assess the nitrification/denitrification processes of surface water, groundwater and precipitation, respectively. This review summarized the analysis technique of nitrate delta15N and delta18O in domestic and abroad, assessed typical values of delta15N, delta18O from different NO3- sources and evaluated the progress in application of dual stable isotope of delta15N and delta18O technique to trace NO3- sources in surface- and ground-water. Both ion exchange-AgNO3 and bacteria denitrifying methods have been successfully used in tracing water nitrate sources nationwide. The comprehensive metadata analysis of nitrate sources showed that the delta15N values of sewage and manure, soil, precipitation, fertilizer ranged from 3 per thousand to 17 per thousand, 3 per thousand to 8 per thousand, - 9 per thousand to 9 per thousand, -2 per thousand to 4 per thousand, respectively. And the delta15N values of ammonium fertilizer ranged from - 4 per thousand to 2 per thousand. According to the stable isotope technique, sewage and manure were identified as the major nitrate sources of surface- and ground-water in China. This indicated that municipal sewage and aquaculture exerted serious influence on the nitrate pollution of surface water. In the future, long-term monitoring, dual stable isotope fingerprinting and hydro-chemical analysis should be applied together to quantitatively differentiate contribution of nitrate sources, and to assess seasonal dynamic of nitrate sources. It will provide useful

  16. Remediation of Nitrate-contaminated Groundwater by a Mixture of Iron and Activated Carbon

    Science.gov (United States)

    Huang, Guoxin; Liu, Fei; Jin, Aifang; Qin, Xiaopeng

    2010-11-01

    Nitrate contamination in groundwater has become a major environmental and health problem worldwide. The aim of the present study is to remediate groundwater contaminated by nitrate and develop potential reactive materials to be used in PRBs (Permeable Reactive Barriers). A new approach was proposed for abiotic groundwater remediation by reactive materials of iron chips and granular activated carbon particles. Batch tests were conducted and remediation mechanisms were discussed. The results show that nitrate decreases from 86.31 to 33.79 mgṡL-1 under the conditions of near neutral pH and reaction time of 1h. The combination of iron chips and activated carbon particles is cost-effective and suitable for further use as denitrification media in PRBs. Nitrogen species don't change significantly with the further increase in reaction time (>1 h). The iron-activated carbon-water-nitrate system tends to be steady-state. Small amounts of ammonium and nitrite (0.033-0.039 and 0.14-3.54 mgṡL-1, respectively) appear at reaction time from 0 h to 5 h. There is no substantial accumulation of nitrogen products in the system. The removal rate of nitrate only reaches 16.11% by sole iron chips at reaction time of 5 h, while 63.57% by the mixture of iron chips and activated carbon particles. There is significantly synergistic and promotive effect of mixing the two different types of materials on nitrate treatment. Fe/C ratio (1/1.5-1/2.5) doesn't cause dramatically different residual nitrate concentrations (24.09-26.70 mgṡL-1). Nitrate can't be limitlessly decreased with decreasing Fe/C ratio. The concomitant occurrences of chemical reduction, galvanic cell reaction, electrophoretic accumulation, chemical coagulation, and physical adsorption are all responsible for the overall nitrate removal by iron allied with activated carbon. To accurately quantify various nitrogen species, further studies on adsorption mechanisms of nitrite and nitrate are needed.

  17. Influence of Chemical Oxygen Demand Concentrations on Anaerobi Ammonium Oxidation by Granular Sludge From EGSB Reactor

    Institute of Scientific and Technical Information of China (English)

    JING KANG; JIAN-LONG WANG

    2006-01-01

    Objective To investigate the effect of chemical oxygen demand (COD) concentrations on the anaerobic ammonium oxidation (ANAMMOX). Methods An Expanded Granular Sludge Bed (EGSB) reactor was used to cultivate the granular sludge and to perform the ANAMMOX reaction in the bench scale experiment. NH4+-N and NO2--N were measured by usingcolorimetric method. NO3--N was analyzed by using the UV spectrophotometric method. COD measurement was based on digestion with potassium dichromate in concentrated sulphuric acid. Results When the COD concentrations in the reactors were 0 mg/L, 200 mg/L, 350 mg/L, and 550 mg/L, respectively, the NH4+-N removal efficiency was 12.5%, 14.2%, 14.3%, and 23.7%; the removal amount of NO2--N was almost the same; the nitrate removal efficiency was 16.8%, 94.5%, 86.6%, and 84.2% and TN removal efficiency was 16.3%, 50.7%, 46.9%, and 50.4%, moreover, the COD removal efficiency concentrations have a significant influence on anaerobic ammonium oxidation by granular sludge.

  18. Experience with a uranyl nitrate/uranium dioxide conversion pilot plant

    International Nuclear Information System (INIS)

    A plant for the precipitation of sinterable nuclear grade UO2 powders is described in this report. The plant has been designed, built and set up by SNIA TECHINT. ENEA has been involved in the job as nuclear consultant. Main process steps are: dissolution of UO2 powder or sintered UO2 pellets, adjustment of uranyl nitrate solutions, precipitation of uranium peroxide by means of hydrogen peroxide, centrifugation of the precipitate, drying, calcination and reduction to uranium dioxide. The report is divided in two main section: the process description and the ''hot test'' report. Some laboratory data on precipitation of ammonium diuranate by means of NH4OH, are also reported

  19. Effects of Nitrogen Application on Physiological Characteristics of Nitrate-Tolerant Mutants of Soybean

    OpenAIRE

    Hussain, Abul Kashem Mohammed Anwar; Yamakawa, Takeo; Ikeda, Motoki; Ishizuka, Junji

    1992-01-01

    Nitrate-tolerant mutants of soybean (Glycine max 〔L.〕 Merr.), nts1116 and nts1007 and their parent cultivar Bragg were grown in field. Plants were harvested at flowering, pod elongating and pod filling stages; and analyzed for nitrogenous components and sugar. The highest total N and ammonium-N concentration were found in nodules followed by leaf, stem and root. There were small differences in the concentrations between N- and non-N-applied plants. Nts1007 showed higher concentrations in almo...

  20. Effects of Nitrogen Application on Growth and Yield of Nitrate-Tolerant Mutants of Soybean

    OpenAIRE

    Hussain, Abul Kashem Mohammed Anwar; Yamakawa, Takeo; Ikeda, Motoki; Ishizuka, Junji

    1992-01-01

    A field experiment was conducted using nitrate tolerant mutants of soybean (Glycine max IL.1 Merr.) ntsll16 and nts1007 and its parent cv. Bragg as test crops to study the effects of nitrogen application on growth and yield parameters. Nirtogen was fertilized as ammonium sulfate at the rate of 100 kg N/ha. Samples of each line with and without nitrogen application was harvested at flowering, pod filling and maturity stages. Nts1007 in growth parameters were inferior to Bragg and nts1116. The ...

  1. Synthesis of porous poly(acrylamide hydrogels using calcium carbonate and its application for slow release of potassium nitrate

    Directory of Open Access Journals (Sweden)

    2009-05-01

    Full Text Available Porous poly(acrylamide was synthesized using calcium carbonate microparticles and subsequent acid treatment to remove the calcium carbonate. Methylenebisacrylamide and ammonium persulfate/sodium metabisulfite were used as crosslinking agent and redox initiator, respectively. The porous structure of resulted hydrogels was confirmed using SEM micrographs. The effect of methylenebisacrylamide concentration and calcium carbonate amount on the swelling of the hydrogels was investigated. The results showed that the effect of methylenebisacrylamide and calcium carbonate variables on the swelling is reverse. The hydrogels were subsequently utilized for the loading of potassium nitrate. Potassium nitrate as active agent was loaded into hydrogels and subsequently the release of this active agent was investigated. In these series of investigation, the effect of content of loading, methylenebisacrylamide and calcium carbonate amount on the release of potassium nitrate from hydrogels was investigated.

  2. Assimilatory nitrate utilization by bacteria on the West Florida Shelf as determined by stable isotope probing and functional microarray analysis.

    Science.gov (United States)

    Wawrik, Boris; Boling, Wilford B; Van Nostrand, Joy D; Xie, Jianping; Zhou, Jizhong; Bronk, Deborah A

    2012-02-01

    Dissolved inorganic nitrogen (DIN) uptake by marine heterotrophic bacteria has important implications for the global nitrogen (N) and carbon (C) cycles. Bacterial nitrate utilization is more prevalent in the marine environment than traditionally thought, but the taxonomic identity of bacteria that utilize nitrate is difficult to determine using traditional methodologies. (15) N-based DNA stable isotope probing was applied to document direct use of nitrate by heterotrophic bacteria on the West Florida Shelf. Seawater was incubated in the presence of 2 μM (15) N ammonium or (15) N nitrate. DNA was extracted, fractionated via CsCl ultracentrifugation, and each fraction was analyzed by terminal restriction fragment length polymorphism (TRFLP) analysis. TRFs that exhibited density shifts when compared to controls that had not received (15) N amendments were identified by comparison with 16S rRNA gene sequence libraries. Relevant marine proteobacterial lineages, notably Thalassobacter and Alteromonadales, displayed evidence of (15) N incorporation. RT-PCR and functional gene microarray analysis could not demonstrate the expression of the assimilatory nitrate reductase gene, nasA, but mRNA for dissimilatory pathways, i.e. nirS, nirK, narG, nosZ, napA, and nrfA was detected. These data directly implicate several bacterial populations in nitrate uptake, but suggest a more complex pattern for N flow than traditionally implied. PMID:22092701

  3. Deconstructing nitrate isotope dynamics in aquifers

    Science.gov (United States)

    Granger, J.

    2012-12-01

    The natural abundance N and O stable isotope ratios of nitrate provide an invaluable tool to differentiate N sources to the environment, track their dispersal, and monitor their attenuation by biological transformations. The interpretation of patterns in isotope abundances relies on knowledge of the isotope ratios of the source end-members, as well as on constraints on the isotope discrimination imposed on nitrate by respective biological processes. Emergent observations from mono-culture experiments of denitrifying bacteria reveal nitrate fractionation trends that appear at odds with trends ascribed to denitrification in soils and aquifers. This discrepancy raises the possibility that additional biological N transformations may be acting in tandem with denitrification. Here, the N and O isotope enrichments associated with nitrate removal by denitrification in aquifers are posited to bear evidence of coincident biological nitrate production - from nitrification and/or from anammox. Simulations are presented from a simple time-dependent one-box model of a groundwater mass ageing that is subject to net nitrate loss by denitrification with coincident nitrate production by nitrification or anammox. Within boundary conditions characteristic of freshwater aquifers, the apparent slope of the parallel enrichments in nitrate N and O isotopes associated with net N loss to denitrification can vary in proportion to the nitrate added simultaneous by oxidative processes. Pertinent observations from nitrate plumes in suboxic to anoxic aquifers are examined to validate this premise. In this perspective, nitrate isotope distributions suggest that we may be missing important N fluxes inherent to most aquifers.

  4. Characterizing the thermodynamic and chemical composition factors controlling PM2.5 nitrate: Insights gained from two years of online measurements in Hong Kong

    Science.gov (United States)

    Griffith, Stephen M.; Huang, X. H. Hilda; Louie, P. K. K.; Yu, Jian Zhen

    2015-12-01

    In this study, we investigated the seasonal, diurnal, and episodic characteristics of aerosol nitrate concentrations in PM2.5 at a suburban receptor site in Hong Kong using an hourly MARGA sampled dataset. At the site, large spikes in the NO3- concentration have been observed in all seasons, and are easily overlooked in datasets examining 24 h average concentrations. As a key component to PM2.5, nitrate constituted between 5 and 12% of the mass concentration on average per month, but contributed up to 25% during some episodic cases spanning only a few hours. Seasonal variations of PM2.5 nitrate concentrations at the site were driven by temperature and excess [NH4+] in the aerosol, defined as the amount of ammonium in excess of that required for satisfying [NH4+]/[SO42-] = 1.5. The vast majority of winter nitrate data was associated with ammonium-rich aerosols ([NH4+]/[SO42-] > 1.5), with the diurnal variation tracking the availability of excess [NH4+]. Distinctly different than winter conditions, the summer nitrate data was in ammonium-poor regime and tracked nitric acid concentrations, a photochemical tracer. A regression analysis of measured nitrate with the excess [NH4+] shows good correlation in spring, summer and winter (R2: 0.72-0.81), with slopes greater than 0.7 indicating the majority of excess NH4+ is associated with PM2.5 nitrate. It was found that measured nitrate exceeded excess [NH4+] in samples of low excess [NH4+] availability, leading to our finding that nitric acid attaching to sea salt and crustal particles in the fine mode is a non-negligible route (constituting up to ∼20% of the PM2.5 nitrate in this study) to assimilate nitrate into the PM2.5 aerosol. Accounting for both this minor route and the ammonia + nitric acid route may prove useful in modeling efforts to capture PM2.5 nitrate measurement fluctuations, particularly during events of a large influx of alkali particles, such as dust storms.

  5. Collection of Nitrate in a Denuder

    Directory of Open Access Journals (Sweden)

    Hannah Feig

    2008-01-01

    Full Text Available Data are given for aerosol nitrate (NO3- size distributions in the atmosphere as recorded by a cascade impactor and by an annular denuder. Using this data, our goal is to find the percent of nitrate in the atmosphere that the denuder is able to detect. This requires that we find the size distribution of nitrate that enters the denuder. From these data and calculations, we find that 32.8% of nitrate in the atmosphere can be detected by the denuder. Nitrate was measured to study its affects on seagrass in the Tampa Bay and to compare nitrate levels with seagrass growth and decline. Using a denuder for routine measurements will not allow scientists to accurately compare nitrate data to seagrass levels.

  6. Extraction chemistry of uranyl nitrate and nitric acid in high concentration systems

    International Nuclear Information System (INIS)

    HNO3 is extracted in significant quantities by uranyl nitrate solvates with diferent extractants: TBP (tributyl phosphate), TOPO (trioctyl phosphine oxide) and TDA (tetradecyl ammonium). The effect of diluent nature is not observed on extracting HNO3 and TBP saturated by uranium at equilibrium with its salt using the diluents (CCl4, C6H5Cl, C12H26, CHCl3) which are less polar than UO2(NO3)2(TBP)2 . HNO3 occurs in organic phase as undissociated form and its state is similar to pure anhydrous HNO3 . Solvates of TBP and TDA with uranyl nitrate dissolve HNO3 without displacement of uranium from organic phase. (author) 13 refs.; 2 figs.; 2 tabs

  7. Saline wastewater treatment by Chlorella vulgaris with simultaneous algal lipid accumulation triggered by nitrate deficiency.

    Science.gov (United States)

    Shen, Qiao-Hui; Gong, Yu-Peng; Fang, Wen-Zhe; Bi, Zi-Cheng; Cheng, Li-Hua; Xu, Xin-Hua; Chen, Huan-Lin

    2015-10-01

    Chlorella vulgaris, a marine microalgae strain adaptable to 0-50 g L(-1) of salinity, was selected for studying the coupling system of saline wastewater treatment and lipid accumulation. The effect of total nitrogen (T N) concentration was investigated on algal growth, nutrients removal as well as lipid accumulation. The removal efficiencies of TN and total phosphorus (TP) were found to be 92.2-96.6% and over 99%, respectively, after a batch cultivation of 20 days. To illustrate the response of lipid accumulation to nutrients removal, C. vulgaris was further cultivated in the recycling experiment of tidal saline water within the photobioreactor. The lipid accumulation was triggered upon the almost depletion of nitrate (nitrate, nitrite, and then to ammonium in the effluents was finally integrated with previous discussions on metabolic pathways of algal cell under nitrogen deficiency. PMID:26117237

  8. Summertime PM2.5 ionic species in four major cities of China: nitrate formation in an ammonia-deficient atmosphere

    Directory of Open Access Journals (Sweden)

    Tao Wang

    2008-06-01

    Full Text Available Strong atmospheric photochemistry in summer can produce a significant amount of secondary aerosols, which may have a large impact on regional air quality and visibility. In the study reported herein, we analyzed sulfate, nitrate, and ammonium in PM2.5 samples collected using a 24-h filter system at suburban and rural sites near four major cities in China (Beijing, Shanghai, Guangzhou, and Lanzhou. Overall, the PM2.5 mass concentrations were high (with a mean value of 55–68 µg m−3, which reflects the long-known particulate pollution in China's large urban centers. We observed very high concentrations of sulfate and nitrate at the Beijing and Shanghai sites, and, in particular, abnormally high levels of nitrate (24-h average concentration up to 42 µg m−3 and contributing up to 25% of the PM2.5 mass in the ammonium-poor samples. The Beijing and Shanghai aerosols were characterized by high levels of aerosol acidity (~220–390 nmol m−3 and low levels of in-situ pH (−0.77 to −0.52. In these samples, the formation of the observed high concentrations of particulate nitrate cannot be explained by homogeneous gas-phase reaction between ammonia and nitric acid. Examination of the relation of nitrate to relative humidity and aerosol loading suggests that the nitrate was most probably formed via the heterogeneous hydrolysis of N2O5 on the surface of the moist and acidic aerosols in Beijing and Shanghai. In comparison, the samples collected in Lanzhou and Guangzhou were ammonium-rich with low levels of aerosol acidity (~65–70 nmol m−3, and the formation of ammonium nitrate via the homogeneous gas-phase reaction was favored, which is similar to many previous studies. An empirical fit has been derived to relate fine nitrate to aerosol acidity, aerosol water content, aerosol surface area, and the precursor of nitrate for the data from Beijing and Shanghai.

  9. Summertime PM2.5 ionic species in four major cities of China: nitrate formation in an ammonia-deficient atmosphere

    Directory of Open Access Journals (Sweden)

    T. Wang

    2009-03-01

    Full Text Available Strong atmospheric photochemistry in summer can produce a significant amount of secondary aerosols, which may have a large impact on regional air quality and visibility. In the study reported herein, we analyzed sulfate, nitrate, and ammonium in PM2.5 samples collected using a 24-h filter system at suburban and rural sites near four major cities in China (Beijing, Shanghai, Guangzhou, and Lanzhou. Overall, the PM2.5 mass concentrations were high (with a mean value of 55–68 gμgm−3, which reflects the long-known particulate pollution in China's large urban centers. We observed very high concentrations of sulfate and nitrate at the Beijing and Shanghai sites, and, in particular, abnormally high levels of nitrate (24-h average concentration up to 42 gμgm−3 and contributing up to 25% of the PM2.5 mass in the ammonium-poor samples. The Beijing and Shanghai aerosols were characterized by high levels of aerosol acidity (~220–390 nmol m−3 and low levels of in-situ pH (−0.77 to −0.52. In these samples, the formation of the observed high concentrations of particulate nitrate cannot be explained by homogeneous gas-phase reaction between ammonia and nitric acid. Examination of the relation of nitrate to relative humidity and aerosol loading suggests that the nitrate was most probably formed via the heterogeneous hydrolysis of N2O5 on the surface of the moist and acidic aerosols in Beijing and Shanghai. In comparison, the samples collected in Lanzhou and Guangzhou were ammonium-rich with low levels of aerosol acidity (~65–70 nmol m−3, and the formation of ammonium nitrate via the homogeneous gas-phase reaction was favored, which is similar to many previous studies. An empirical fit has been derived to relate fine nitrate to aerosol acidity, aerosol water content, aerosol surface area, and the precursor of nitrate for the data from Beijing and Shanghai.

  10. 5-Chloro-8-hydroxyquinolinium nitrate

    Directory of Open Access Journals (Sweden)

    Seik Weng Ng

    2009-06-01

    Full Text Available The 5-chloro-8-hydroxyquinolinium cation in the the title ion pair, C9H7ClNO+·NO3−, is approximately coplanar with the nitrate anion [dihedral angle = 16.1 (1°]. Two ion pairs are hydrogen bonded (2 × O—H...O and 2 × N—H...O about a center of inversion, generating an R44(14 ring.

  11. 2-Amino-5-chloropyridinium nitrate

    Directory of Open Access Journals (Sweden)

    Donia Zaouali Zgolli

    2009-11-01

    Full Text Available The title structure, C5H6ClN2+·NO3−, is held together by extensive hydrogen bonding between the NO3− ions and 2-amino-5-chloropyridinium H atoms. The cation–anion N—H...O hydrogen bonds link the ions into a zigzag- chain which develops parallel to the b axis. The structure may be compared with that of the related 2-amino-5-cyanopyridinium nitrate.

  12. Electrolytic production of uranous nitrate

    International Nuclear Information System (INIS)

    Efficient production of uranous nitrate is important in nuclear fuel reprocessing because U(IV) acts as a plutonium reductant in solvent extraction and can be coprecipitated with plutonium and/or throium as oxalates during fuel reprocessing. Experimental conditions are described for the efficient electrolytic production of uranous nitrate for use as a reductant in the SRP Purex process. The bench-scale, continuous-flow, electrolysis cell exhibits a current efficiency approaching 100% in combination with high conversion rates of U(VI) to U(IV) in simulated and actual SRP Purex solutions. High current efficiency is achieved with a voltage-controlled mercury-plated platinum electrode and the use of hydrazine as a nitrite scavenger. Conversion of U(VI) to U(IV) proceeds at 100% efficiency. Cathodic gas generation is minimal. The low rate of gas generation permits a long residence time within the cathode, a necessary condition for high conversions on a continuous basis. Design proposals are given for a plant-scale, continuous-flow unit to meet SRP production requirements. Results from the bench-scale tests indicate that an 8-kW unit can supply sufficient uranous nitrate reductant to meet the needs of the Purex process at SRP

  13. Physicochemical properties of ammonium-based deep eutectic solvents and their electrochemical evaluation using organometallic reference redox systems

    International Nuclear Information System (INIS)

    Highlights: • Physicochemical properties of seven deep eutectic solvents as electrolytes measured. • Walden plot showed ideal ammonium-based deep eutectic solvents. • Potential windows of all deep eutectic solvents determined. • Diffusion coefficients and rate constants of organometallic redox couples measured. • Rate constants of deep eutectic solvents were lower than those of ionic liquids. -- Abstract: Seven deep eutectic solvents (DESs) containing ammonium based salts are prepared by means of hydrogen bonding with acid, amine, amide and nitrate based compounds. The major physicochemical properties of the DESs in terms of density, viscosity, electrical conductivity, molar conductivity and pH are investigated prior to ascertaining their electrochemical characteristics by means of cyclic voltammetry and chronoamperometry. Nitrate based DESs exhibit higher conductivities but lower viscosities than other DESs, whereas the amide based DES displays the widest electrochemical potential window. Diffusion coefficient, D, of two organometallic redox couples, Fc/Fc+ (ferrocene/ferrocenium) and Cc/Cc+(cobaltocene/cobaltocenium) is found to be of the order of 10−9 to 10−8 cm2 s−1 in all studied DESs while the heterogeneous rate constant for electron transfer across the electrode/DES interface is of the order of 10−4 cm s−1. The Stokes–Einstein products of Fc and Cc+ in the DESs have also been determined

  14. 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.

  15. Effects of cropping system and rates of nitrogen in animal slurry and mineral fertilizer on nitrate leaching from a sandy loam

    DEFF Research Database (Denmark)

    Thomsen, Ingrid Kaag; Hansen, Jørgen Frederik; Kjellerup, Viggo K.;

    1993-01-01

    Leaching of nitrate from a sandy loam cropped with spring barley, winter wheat and grass was compared in a 4-year lysimeter study. Crops were grown continuously or in a sequence including sugarbeet. Lysimeters were unfertilized or supplied with equivalent amounts of inorganic nitrogen in calcium...... ammonium nitrate (CAN) or animal slurry according to recommended rates (1N) or 50% above recommended rates (1.5N). Compared with unfertilized crops, leaching of nitrate increased only slightly when 1N (CAN) was added. Successive annual additions of 1.5N (CAN) or IN and 1.5N (animal slurry) caused...... the four years were similar for the crops when grown in rotation or continuously. When crops received 1:5N (CAN) or animal slurry, nitrate losses from the crops grown continuously exceeded those from crops in rotation. Including a catch crop in the continuous cropping system eliminated the differences...

  16. Studies on inorganic exchangers - ammonium phosphomolybdate (AMP) and ammonium phosphotungstate (APW)

    International Nuclear Information System (INIS)

    Separation of fission product cesium from other accompanying fission products by use of inorganic ion exchangers, namely, ammonium phosphomolybdate (AMP) and ammonium phosphotungstate (APW) has been investigated. The gross fission product solution is passed through a column of AMP or APW conditioned with HNO3 of appropriate molarity say 2M. The column is thoroughly washed with HNO3 till no activity is left in it . Cesium is eluted by 3M NH4NO3 at 40 deg C. The eluate is converted into cesium chloride by wet decomposition method. The radioactive cesium obtained by this procedure is found to be of high purity and free from any other active contaminants. (M.G.B.)

  17. Nitrous Oxide Metabolism in Nitrate-Reducing Bacteria: Physiology and Regulatory Mechanisms.

    Science.gov (United States)

    Torres, M J; Simon, J; Rowley, G; Bedmar, E J; Richardson, D J; Gates, A J; Delgado, M J

    2016-01-01

    Nitrous oxide (N2O) is an important greenhouse gas (GHG) with substantial global warming potential and also contributes to ozone depletion through photochemical nitric oxide (NO) production in the stratosphere. The negative effects of N2O on climate and stratospheric ozone make N2O mitigation an international challenge. More than 60% of global N2O emissions are emitted from agricultural soils mainly due to the application of synthetic nitrogen-containing fertilizers. Thus, mitigation strategies must be developed which increase (or at least do not negatively impact) on agricultural efficiency whilst decrease the levels of N2O released. This aim is particularly important in the context of the ever expanding population and subsequent increased burden on the food chain. More than two-thirds of N2O emissions from soils can be attributed to bacterial and fungal denitrification and nitrification processes. In ammonia-oxidizing bacteria, N2O is formed through the oxidation of hydroxylamine to nitrite. In denitrifiers, nitrate is reduced to N2 via nitrite, NO and N2O production. In addition to denitrification, respiratory nitrate ammonification (also termed dissimilatory nitrate reduction to ammonium) is another important nitrate-reducing mechanism in soil, responsible for the loss of nitrate and production of N2O from reduction of NO that is formed as a by-product of the reduction process. This review will synthesize our current understanding of the environmental, regulatory and biochemical control of N2O emissions by nitrate-reducing bacteria and point to new solutions for agricultural GHG mitigation. PMID:27134026

  18. Nitrate reducing bacterial activity under alkaline conditions found in intermediate-level nuclear waste repositories

    International Nuclear Information System (INIS)

    This study focuses on the bituminous waste, a mixture of bitumen and insoluble salts, mainly of nitrate and sulphate carrying low and intermediate level radioactivity. The re-saturation of the disposal cells after closure will likely lead to the development of microbial activity. One of the most critical aspects limiting bacterial activity is the high alkalinity prevailing in the barrier concrete system and at the concrete-clay rock interface (pH = 11-13.5). The objective of this work is to evaluate the possible activity of nitrate reducing bacteria under these alkaline conditions, building on knowledge for alkaliphilic bacteria gained from similar conditions. Alkaliphilic bacteria develop optimally at pH values above 9, often between 10 and 12, in some cases above 12. They are likely to be predominant under alkaline conditions, but they will be replaced by neutrophilic bacteria as soon as local zones of near-neutral pH develop. In the case of a waste cell this could be at the interface to the clay rock or in the vicinity of organic matter releasing bituminous waste. Two sets of experiments have been carried out, bringing nitrate in contact with a solution containing organic matter (acetate) and a culture of alkaliphilic microbes, one focuses on the influence of nitrate concentrations, the other on the impact of changes in pH (10.0 and 12.4). The results indicate a low microbial activity at pH 12.4 whereas a significant nitrate reduction is obtained at pH 10.0. Furthermore, nitrite is the main product of nitrate reduction; traces of ammonium have also been measured. (authors)

  19. An isotopic study of nitrate pollution of groundwater in Victoria, Australia

    International Nuclear Information System (INIS)

    Nitrate in groundwater can be a hard to human and animal health and contribute to the development of algal blooms and subsequent eutrophication of wetlands. Its presence is widespread throughout Australia and its levels overall appear to be increasing. A variety of sources of nitrate contamination of groundwater are known. These include nitrogen fixing plants, termites, animal wastes, industrial wastes, domestic wastes, sewage and fertilizers. In Victoria, nitrate-rich groundwaters have been reported from a number of localities, some of which include Colac, Nepean Peninsula, Shepparton, Deer Park, Benalla and Winchelsea. A multi-isotope method was developed to determine the probable source of pollution in these localities. Changes in the natural abundance ratio of the stable isotopes of nitrogen, 14N and 15N, and the differences in the isotopic ratios (15N/14N) of nitrate from various sources, form the basis of the N-isotope technique for source identification. Differences in the isotopic ratios of oxygen (18O/16O) and hydrogen (D/H) of polluted and unpolluted waters form the basis for the oxygen and hydrogen isotope technique to investigate pollution problems of groundwater. Sites which included clover, industrial wastes, animal and human wastes and fertilized sources, were selected after reviewing existing databases on nitrate concentration, earlier reports and access to a suitable network of bores for collecting reliable samples. The nitrate concentration ranged from less than 1 mg/L to in excess of 22.0 mg/L, whilst ammonium levels in most samples were less than 1 mg/L. The δ15N values of the various source types ranged from 8.8 to 19.0 per mill (pastures). The δ18O and δD data indicate seawater incursion in the coastal areas of the Nepean Peninsular. The results agree with published data on similar sources from elsewhere in the world, and indicate the potential use of this methodology in groundwater pollution studies in Australia

  20. Overexpression of a pH-sensitive nitrate transporter in rice increases crop yields.

    Science.gov (United States)

    Fan, Xiaorong; Tang, Zhong; Tan, Yawen; Zhang, Yong; Luo, Bingbing; Yang, Meng; Lian, Xingming; Shen, Qirong; Miller, Anthony John; Xu, Guohua

    2016-06-28

    Cellular pH homeostasis is fundamental for life, and all cells adapt to maintain this balance. In plants, the chemical form of nitrogen supply, nitrate and ammonium, is one of the cellular pH dominators. We report that the rice nitrate transporter OsNRT2.3 is transcribed into two spliced isoforms with a natural variation in expression ratio. One splice form, OsNRT2.3b is located on the plasma membrane, is expressed mainly in the phloem, and has a regulatory motif on the cytosolic side that acts to switch nitrate transport activity on or off by a pH-sensing mechanism. High OsNRT2.3b expression in rice enhances the pH-buffering capacity of the plant, increasing N, Fe, and P uptake. In field trials, increased expression of OsNRT2.3b improved grain yield and nitrogen use efficiency (NUE) by 40%. These results indicate that pH sensing by the rice nitrate transporter OsNRT2.3b is important for plant adaption to varied N supply forms and can provide a target for improving NUE. PMID:27274069

  1. A preliminary study on estimating extra-cellular nitrate reductase activities in estuarine systems

    Directory of Open Access Journals (Sweden)

    Pant H. K.

    2009-07-01

    Full Text Available Enzymes catalyzing ammonium (NH4+/nitrate (NO3– into nitrous oxide (N2O/molecular nitrogen (N2, play critical roles in water quality management. The objective of this paper was to investigate the role of extra-cellular enzymes in cycling of nitrogen (N in aquatic systems. It appears that N in estuaries, salt marshes, etc., does not stay long enough to be available for uptake, thus, creating N limited conditions. This study showed that indigenous extra-cellular nitrate reductase along with others involved in N transformations in the waters/sediments of estuarine systems can cause complete removal of NH4+ and NO3– from the waters and available NH4+ and NO3– from the sediments. These results indicate that due to high extra-cellular nitrate reductase and other enzymes associated with N transformations in sediments/waters, substantial amounts of NH4+ and NO3– can be quickly lost from the systems as N2O and/or nitric oxide (NO, in turn, creating N limited conditions in estuarine systems. Such high activities of indigenous nitrate reductase and others are useful in removing readily bioavailable N from the systems, thereby avoidance of eutrophic conditions. However, they might contribute in increasing the N2O, a potent greenhouse gas with global warming potential (GWP of 296, in the atmosphere.

  2. Arabidopsis nitrate reductase activity is stimulated by the E3 SUMO ligase AtSIZ1.

    Science.gov (United States)

    Park, Bong Soo; Song, Jong Tae; Seo, Hak Soo

    2011-01-01

    Small ubiquitin-related modifier (SUMO) is a small polypeptide that modulates protein activity and regulates hormone signalling, abiotic and biotic responses in plants. Here we show that AtSIZ regulates nitrogen assimilation in Arabidopsis through its E3 SUMO ligase function. Dwarf plants of siz1-2 flower early, show abnormal seed development and have high salicylic acid content and enhanced resistance to bacterial pathogens. These mutant phenotypes are reverted to wild-type phenotypes by exogenous ammonium but not by nitrate, phosphate or potassium. Decreased nitrate reductase activity in siz1-2 plants resulted in low nitrogen concentrations, low nitric oxide production and high nitrate content in comparison with wild-type plants. The nitrate reductases, NIA1 and NIA2, are sumoylated by AtSIZ1, which dramatically increases their activity. Both sumoylated and non-sumoylated NIA1 and NIA2 can form dimers. Our results indicate that AtSIZ1 positively controls nitrogen assimilation by promoting sumoylation of NRs in Arabidopsis. PMID:21772271

  3. REGULATION OF NITRATE REDUCTASE ACTIVITY IN RICE (ORYZA SATIVA L. BY GROWTH REGULATORS

    Directory of Open Access Journals (Sweden)

    S HEMALATHA

    2002-12-01

    Full Text Available The effect of three growth regulators, namely kinetin, 6 benzyl adenine, 2 chloro ethyl trimethyl ammonium chloride at three concentrations (10-6 M, 5 x 10-5 M 10-4 M was studied on the catalytic activity of nitrate reductase in green and etiolated seedlings. A concentration of 5 x 10-5 M was optimal for all the growth regulators treatments. All the growth regulators stimulated nitrate reductase activity effectively at 5 x 10-5M concentration in both etiolated and green seedlings and had an additive effect when supplemented by NO-3 up to 140% to 160%. The 99.2% and 93.4% inhibition of nitrate reductase activity resulted in development of etiolated and green seedlings, respectively when treated with eukaryotic 80S ribosome protein synthesis inhibitor cycloheximide. Prokaryotic 70S inhibitor chloromphenicol did not have any effect on measured parameters. Actinomycin D, a RNA synthesis inhibitor also inhibited the enzyme activity as 80s inhibitors (Green 80%, etiolated 98%. One may suggest from this that both DNA and protein synthesis are involved in the induction of nitrate reductase activity. The differential effect of aminoacids was observed on enzyme activity in combination with growth regulators.

  4. Surge ammonium uptake in macroalgae from a coral atoll

    Digital Repository Service at National Institute of Oceanography (India)

    Raikar, V.; Wafar, M.V.M.

    (Phaeophyta)) from Kavaratti atoll (Lakshadweep, India). Addition of ammonium (up to 20 mmol L-1) led to pronounced uptake within 4–6 min, with the amount of ammonium taken up during surge phase (<4 min) accounting for from about half to 10 times that taken up...

  5. Racer (Ammonium Nonanoate) weed control evaluation for onions

    Science.gov (United States)

    Racer has been labeled as a herbicide for food use and is currently under consideration as an organic herbicide for organically grown food crops. The main component (40%) of Racer is ammonium nonanoate (ammonium pelargonate), which occurs in nature and primarily formed from biodegradation of higher...

  6. Thermal decomposition of ammonium perchlorate during gamma-ray irradiation

    International Nuclear Information System (INIS)

    To assess radiation damage effects in propellants, pyrotechnics, and similar materials, thermal decomposition measurements were made on ammonium perchlorate powders and crystals during gamma-ray irradiation. Gas evolution studies were made on single crystals and powders of ammonium perchlorate, both at room temperature and at 2270C. The results are discussed. (U.S.)

  7. 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

  8. Effect of nitrate on microbial perchlorate reduction

    Science.gov (United States)

    Sun, Y.; Coates, J. D.

    2007-12-01

    Over the last decade perchlorate has been recognized as an important emerging water contaminant that poses a significant public health threat. Because of its chemical stability, low ionic charge density, and significant water solubility microbial remediation has been identified as the most feasible method for its in situ attenuation. Our previous studies have demonstrated that dissimilatory perchlorate reducing bacteria (DPRB) capable of the respiratory reduction of perchlorate into innocuous chloride are ubiquitous in soil and sedimentary environments. As part of their metabolism these organisms reduce perchlorate to chlorite which is subsequently dismutated into chloride and molecular oxygen. These initial steps are mediated by the perchlorate reductase and chlorite dismutase enzymes respectively. Previously we found that the activity of these organisms is dependent on the presence of molybdenum and is inhibited by the presence of oxygen and to different extents nitrate. However, to date, there is little understanding of the mechanisms involved in the regulation of perchlorate reduction by oxygen and nitrate. As a continuation of our studies into the factors that control DPRB activity we investigated these regulatory mechanisms in more detail as a model organism, Dechloromonas aromatica strain RCB, transitions from aerobic metabolism through nitrate reduction to perchlorate reduction. In series of growth transition studies where both nitrate and perchlorate were present, preference for nitrate to perchlorate was observed regardless of the nitrate to perchlorate ratio. Even when the organism was pre-grown anaerobically in perchlorate, nitrate was reduced prior to perchlorate. Using non-growth washed cell suspension, perchlorate- grown D. aromatica was capable of reducing both perchlorate and nitrate concomitantly suggesting the preferentially utilization of nitrate was not a result of enzyme functionality. To elucidate the mechanism for preferential utilization of

  9. Fast photolysis of carbonyl nitrates from isoprene

    Science.gov (United States)

    Müller, Jean-Francois; Peeters, Jozef; Stavrakou, Trisevgeni

    2014-05-01

    We show that photolysis is, by far, the major atmospheric sink of isoprene-derived carbonyl nitrates. Empirical evidence from published laboratory studies on the absorption cross sections and photolysis rates of α-nitrooxy ketones suggests that the presence of the nitrate group (i) greatly enhances the absorption cross sections, and (ii) facilitates dissociation to a point that the photolysis quantum yield is close to unity, with O-NO2 dissociation as the likely major channel. On this basis, we provide new recommendations for estimating the cross sections and photolysis rates of carbonyl nitrates. The newly estimated photorates are validated using a chemical box model against measured temporal profiles of carbonyl nitrates in an isoprene oxidation experiment by Paulot et al. (2009). The comparisons for ethanal nitrate and for the sum of methacrolein- and methylvinylketone nitrates strongly supports our assumptions of large cross section enhancements and a near-unit quantum yield for these compounds. These findings have significant atmospheric implications, as carbonyl nitrates constitute an important component of the total organic nitrate pool over vegetated areas: the photorates of key carbonyl nitrates from isoprene are estimated to be typically between ~3 and 20 times higher than their sink due to reaction with OH in relevant atmospheric conditions. Moreover, since the reaction is expected to release NO2, photolysis is especially effective in depleting the total organic nitrate pool.

  10. A global model simulation of present and future nitrate aerosols and their direct radiative forcing of climate

    Directory of Open Access Journals (Sweden)

    D. A. Hauglustaine

    2014-03-01

    Full Text Available The ammonia cycle and nitrate particle formation have been introduced in the LMDz-INCA global model. Both fine nitrate particles formation in the accumulation mode and coarse nitrate forming on existing dust and sea-salt particles are considered. The model simulates distributions of nitrates and related species in agreement with previous studies and observations. The calculated present-day total nitrate direct radiative forcing since the pre-industrial is −0.056 W m−2. This forcing has the same magnitude than the forcing associated with organic carbon particles and represents 18% of the sulfate forcing. Fine particles largely dominate the nitrate forcing representing close to 90% of this value. The model has been used to investigate the future changes in nitrates and direct radiative forcing of climate based on snapshot simulations for the four Representative Concentration Pathway (RCP scenarios and for the 2030, 2050 and 2100 time horizons. Due to a decrease in fossil fuel emissions in the future, the concentrations of most of the species involved in the nitrate-ammonium-sulfate system drop by 2100 except for ammonia which originates from agricultural practices and for which emissions significantly increase in the future. Despite the decrease of nitrate surface levels in Europe and Northern America, the global burden of accumulation mode nitrates increases by up to a factor of 2.6 in 2100. This increase in nitrate in the future arises despite decreasing NOx emissions due to increased availability of ammonia to form ammonium nitrate. The total aerosol direct forcing decreases from its present-day value of −0.234 W m−2 to a range of −0.070 to −0.130 W m−2 in 2100 based on the considered scenario. The direct forcing decreases for all aerosols except for nitrates for which the direct negative forcing increases to a range of −0.060 to −0.115 W m−2 in 2100. Including nitrates in the radiative forcing calculations increases the

  11. Platelet adhesive resistance of segmented polyurethane film surface-grafted with vinyl benzyl sulfo monomer of ammonium zwitterions.

    Science.gov (United States)

    Zhang, Jun; Yuan, Jiang; Yuan, Youling; Zang, Xiaopeng; Shen, Jian; Lin, Sicong

    2003-10-01

    Platelet from human plasma adhered on the segmented poly(ether urethane) (SPEU) film grafted with N,N-dimethyl-N-(p-vinylbenyl)-N-(3-sulfopropyl) ammonium (DMVSA) was studied. SPEU films were hydroxylated by potassium peroxosulfate (KPS) and then grafted with DMVSA using ceric ammonium nitrate (CAN) as initiator. The mixing time of hydroxylated SPEU/CAN and the monomer concentration effect on graft polymerization yield were determined by ATR-FTIR. Surface analysis of the grafted films by ATR-FTIR and ESCA confirmed that DMVSA was successfully grafted onto the SPEU film surface. The grafted film possessed a relatively hydrophilic surface, as revealed by water contact angle measurement. The improved blood compatibility of the grafted films was preliminarily evaluated by a platelet-rich plasma adhesion study and scanning electron microscopy, using original SPEU and hydroxylated SPEU films as the controls. The results showed that platelet attachment was decreased greatly on the segmented polyurethane films grafted with DMVSA. This kind of new biomaterials grafted with sulfo ammonium zwitterionic monomers might have potential for biomedical applications. PMID:12853253

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

    Science.gov (United States)

    Li, Xiao-Ming; Yang, Qi; Zeng, Guang-Ming; Cornelius, A; Rosenwinkel, K H; Kunst, S; Weichgrebe, D

    2004-01-01

    Modeling for nitritation process was discussed and analyzed quantitatively 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. PMID:15900739

  13. Biological nitrate transport in sediments on the Peruvian margin mitigates benthic sulfide emissions and drives pelagic N loss during stagnation events

    Science.gov (United States)

    Dale, A. W.; Sommer, S.; Lomnitz, U.; Bourbonnais, A.; Wallmann, K.

    2016-06-01

    Benthic N cycling in the Peruvian oxygen minimum zone (OMZ) was investigated at ten stations along 12 °S from the middle shelf (74 m) to the upper slope (1024 m) using in situ flux measurements, sediment biogeochemistry and modeling. Middle shelf sediments were covered by mats of the filamentous bacteria Thioploca spp. and contained a large 'hidden' pool of nitrate that was not detectable in the porewater. This was attributed to a biological nitrate reservoir stored within the bacteria to oxidize sulfide during 'dissimilatory nitrate reduction to ammonium' (DNRA). The extremely high rates of DNRA on the shelf (15.6 mmol m-2 d-1 of N), determined using an empirical steady-state model, could easily supply all the ammonium requirements for anammox in the water column. The model further showed that denitrification by foraminifera may account for 90% of N2 production at the lower edge of the OMZ. At the time of sampling, dissolved oxygen was below detection limit down to 400 m and the water body overlying the shelf had stagnated, resulting in complete depletion of nitrate and nitrite. A decrease in the biological nitrate pool was observed on the shelf during fieldwork concomitant with a rise in porewater sulfide levels in surface sediments to 2 mM. Using a non-steady state model to simulate this natural anoxia experiment, these observations were shown to be consistent with Thioploca surviving on a dwindling intracellular nitrate reservoir to survive the stagnation period. The model shows that sediments hosting Thioploca are able to maintain high ammonium fluxes for many weeks following stagnation, potentially sustaining pelagic N loss by anammox. In contrast, sulfide emissions remain low, reducing the economic risk to the Peruvian fishery by toxic sulfide plume development.

  14. Behaviour of nitrate present in nuclear waste and impact on repository chemistry and safety

    International Nuclear Information System (INIS)

    Document available in extended abstract form only. We will focus here on nitrates disposal in clay-rich sedimentary host rocks with concrete engineered barriers because of nitrates massive presence in the waste and because of the likely increase in redox potential related to its presence. The fate and effect of nitrate in the alkaline concrete waste cell and in the circum-neutral clay host rocks is essentially controlled by the type of catalysis required for its reduction. The surface catalysis by different steel components and corrosion products with the formation of ammonium will be in competition with microbial reactions, which are more likely to form nitrite or nitrogen bearing gases. We nonetheless wish to consider the impact of nitrate together with the other main redox-determining electron acceptors of the electrochemical series: O2 → NO3- → Fe3+ → SO42- → CO32- → H2O; the former true oxidising species, the latter electron acceptors under anaerobic conditions. All are commonly encountered electron acceptors, with each of them able to set the redox potential, when the preceding substances drop below threshold concentrations. We can illustrate the evolution of such a redox sequence using a waste disposal cell where all of the main electron acceptors are initially present. During excavation and exploitation the host rock with a redox potential controlled by the couple sulphide/sulphate will be perturbed by the arrival of oxygen, which is likely to react with electron donors massively present either in the host rock, in the concrete or in the waste container, with pyrite, siderite, Fe(II) in clay minerals, organic matter, as the most important mineralogical assemblage and Fe(0) as main representative of zero-valent metals present in the different steel types. The oxidation of reduced S or Fe to sulphate or ferric ions will increase the size of the pool of electron acceptors that will become reactive once oxygen is depleted. Yet, if nitrate is present

  15. Higher Ammonium Transamination Capacity Can Alleviate Glutamate Inhibition on Winter Wheat (Triticum aestivum L.) Root Growth under High Ammonium Stress.

    Science.gov (United States)

    Wang, Feng; Gao, Jingwen; Liu, Yang; Tian, Zhongwei; Muhammad, Abid; Zhang, Yixuan; Jiang, Dong; Cao, Weixing; Dai, Tingbo

    2016-01-01

    Most of the studies about NH4+ stress mechanism simply address the effects of free NH4+, failing to recognize the changed nitrogen assimilation products. The objective of this study was to elucidate the effects of glutamate on root growth under high ammonium (NH4+) conditions in winter wheat (Triticum aestivum L.). Hydroponic experiments were conducted using two wheat cultivars, AK58 (NH4+-sensitive) and Xumai25 (NH4+-tolerant) with either 5 mM NH4+ nitrogen (AN) as stress treatment or 5 mM nitrate (NO3-) nitrogen as control. To evaluate the effects of NH4+-assimilation products on plant growth, 1 μM L-methionine sulfoximine (MSO) (an inhibitor of glutamine synthetase (GS)) and 1 mM glutamates (a primary N assimilation product) were added to the solutions, respectively. The AN significantly reduced plant biomass, total root length, surface area and root volume in both cultivars, but less effect was observed in Xumai25. The inhibition effects were alleviated by the application of MSO but strengthened by the application of glutamate. The AN increased the activities of GS, glutamate dehydrogenase (GDH) in both cultivars, resulting in higher glutamate contents. However, its contents were decreased by the application of MSO. Compared to AK58, Xumai25 showed lower glutamate contents due to its higher activities of glutamic-oxaloacetic transaminase (GOT) and glutamic-pyruvic transaminase (GPT). With the indole-3-acetic acid (IAA) contents decreasing in roots, the ratio of shoot to root in IAA was increased, and further increased by the application of glutamate, and reduced by the application of MSO, but the ratio was lower in Xumai25. Meanwhile, the total soluble sugar contents and its root to shoot ratio also showed similar trends. These results indicate that the NH4+-tolerant cultivar has a greater transamination ability to prevent glutamate over-accumulation to maintain higher IAA transport ability, and consequently promoted soluble sugar transport to roots, further

  16. Nitrate contamination of groundwater and its countermeasures

    Energy Technology Data Exchange (ETDEWEB)

    Mitamura, Hisayoshi [Japan Atomic Energy Research Inst., Tokai, Ibaraki (Japan). Tokai Research Establishment

    2003-03-01

    The inevitable increases of food production and energy consumption with an increase in world population become main causes of an increase of nitrate load to the environment. Although nitrogen is essential for the growth of animal and plant as a constituent element of protein, excessive nitrate load to the environment contaminates groundwater resources used as drinking water and leads to seriously adverse effects on the health of man and livestock. In order to clarify the problem of nitrate contamination of groundwater and search a new trend of technology development from the viewpoint of environment remediation and protection, the present paper has reviewed adverse effects of nitrate on human health, the actual state of nitrogen cycle, several kinds of nitrate sources, measures for reducing nitrate level, etc. (author)

  17. Nitrate contamination of groundwater and its countermeasures

    International Nuclear Information System (INIS)

    The inevitable increases of food production and energy consumption with an increase in world population become main causes of an increase of nitrate load to the environment. Although nitrogen is essential for the growth of animal and plant as a constituent element of protein, excessive nitrate load to the environment contaminates groundwater resources used as drinking water and leads to seriously adverse effects on the health of man and livestock. In order to clarify the problem of nitrate contamination of groundwater and search a new trend of technology development from the viewpoint of environment remediation and protection, the present paper has reviewed adverse effects of nitrate on human health, the actual state of nitrogen cycle, several kinds of nitrate sources, measures for reducing nitrate level, etc. (author)

  18. Bacterial Investigation of Ammonium-rich Sediment in the Pearl River Delta, China

    Science.gov (United States)

    Liu, K.; Chunbo, H.; Jiao, J. J.; Jidong, G.

    2011-12-01

    High ammonium loading of groundwater is a major concern because of the potential toxicity to ecosystem and human health. As one of the most complex large-scale delta systems in China, Pearl River Delta (PRD) was reported to have the highest ammonium concentration for natural groundwater ever reported globally. In this research, borehole SD14 was drilled through the aquitard into the basal aquifer in the PRD. 16S rRNA gene library construction and Denaturing Gradient Gel Electrophoresis (DGGE) analysis were conducted to reveal bacterial community variation of different geology strata. A total of 161 clones from three 16S rRNA libraries were sequenced and clustered into 55 distinct operational taxonomic units (OTU) at 3% cutoff. The phylogenetic analysis indicated that the predominant bacterial phylum was Proteobacteria (50.9%), followed by Chloroflexi (16.8%), Acidobacteria (4.38%) and Firmicutes (3.73%). In the sediment samples from SD14 at the depths of 6.9m, 22.5m and 37.4m, Proteobacteria made up 60.3%, 42.0% and 35.3% of the communities respectively, showing a declining ratio with the depth. Most of the bacteria in all the samples were previously discovered in marine environments, indicating that SD14 used to be in a marine sedimentary environment. Bacteria associated with iron oxidation and nitrogen fixing were found in the sample at 6.9 m, while in the other two samples there existed bacteria which were associated with methane cycling, sulfate reducing and denitrifying. The DGGE results showed that microbial community structures varied significantly with the increase of depth, and that Delftia acidovorans, a species of Proteobacteria which was able to reduce nitrate to nitrite, was the predominant species in samples at 22.5 and 37.4 m, suggesting ammonium as a control factor shaping the bacterial community. The results of this research provided important information of the bacteria in the PRD sediments. High bacterial diversity was observed in samples, and

  19. Inhaled plutonium nitrate in dogs

    International Nuclear Information System (INIS)

    The major objective of this project is to determine dose-effect relationships of inhaled plutonium nitrate in dogs to aid in predicting health effects of accidental exposure in man. For lifespan dose-effect studies, beagle dogs were given a single inhalation exposure to 239Pu(NO3)4, in 1976 and 1977. The earliest biological effect was on the hematopoietic system; lymphopenia and neutropenia occurred at the two highest dose levels. The authors have also observed radiation pneumonitis, lung cancer, and bone cancer at the three highest dose levels. 1 figure, 4 tables

  20. Inhaled plutonium nitrate in dogs

    International Nuclear Information System (INIS)

    The major objective of this project is to determine dose-effect relationships of inhaled plutonium nitrate in dogs to aid in predicting health effects of accidental exposure in man. For lifespan dose-effect studies, beagle dogs were given a single inhalation exposure to 239Pu(NO3)4, in 1976 and 1977. The earliest biological effect was on the hematopoietic system; lymphopenia and neutropenia occurred at the two highest dose levels. They have also observed radiation pneumonitis, lung cancer, and bone cancer at the three highest dose levels. 1 figure, 3 tables

  1. Nitrate leaching from Silage Maize

    OpenAIRE

    Hansen, Elly Møller; Eriksen, Jørgen

    2009-01-01

    During the last 20 years the area with maize in Denmark has increased dramatically and reached 163,000 ha in 2008. Silage maize is easy to grow, is a suitable fodder for cows and goes well with grass-clover in the diet. This means that silage maize is often found in crop rotations with grass-clover on sandy soils in western Denmark. The ploughing in of grass-clover fields poses a serious risk of increased nitrate leaching on a coarse sandy soil, even when carried out in spring. With increased...

  2. Separating cesium 137 from liquid radioactive wastes by using inorganic exchangers using static and dynamic procedures at various concentration of nitric acid and sodium nitrate

    International Nuclear Information System (INIS)

    Cesium 137 was separated from liquid wastes by ion exchange using ammonium molybdenum phosphate, potassium hexa cyano cobalt ferrate, zirconium hydro phosphate and antimony penta oxy hydrate ion exchangers. The investigation was done by static and dynamic procedures. In static procedure required time for reaching the system to equilibrium or ion exchange completion, the measurement of each exchanger, the effect of nitric acid and concentration of sodium nitrate on the capacity of ion exchangers was investigated. Also in dynamic procedure nitric acid and sodium nitrate concentration ratio on the power of and thereof the capacity of each ion exchanger was determined

  3. Synergic liquid-liquid extraction studies of neodymium and praseodymium with mixtures of tributyl phosphate and Aliquat-336 in nitrate media

    International Nuclear Information System (INIS)

    Extraction studies of neodymium and praseodymium with mixtures of tributyl phosphate and Aliquat-336 in xylene have been carried out. From 3.0M aqueous ammonium nitrate solutions, negatively charged complexes of neodymium and praseodymium were extracted with Aliquat-336 in the presence of tributyl phosphate into the organic phase. The synergic extracted species observed was M(NO3)4-L+*TBP. The synergic extraction of lanthanide elements in nitrate media increases from lanthanum to lutetium. (author) 9 refs.; 9 figs.; 4 tabs

  4. Nitrogen regulation of nasA and the nasB operon, which encode genes required for nitrate assimilation in Bacillus subtilis.

    OpenAIRE

    Nakano, M M; Yang, F; Hardin, P; Zuber, P.

    1995-01-01

    The divergently transcribed nasA gene and nasB operon are required for nitrate and nitrite assimilation in Bacillus subtilis. The beta-galactosidase activity of transcriptional lacZ fusions from the nasA and nasB promoters was high when cells were grown in minimal glucose medium containing poor nitrogen sources such as nitrate, proline, or glutamate. The expression was very low when ammonium or glutamine was used as the sole nitrogen source. The repression of the genes during growth on good s...

  5. Water Pollution with Nitrates from Agricultural Sources

    OpenAIRE

    FLESERIU A.; OROIAN I.

    2010-01-01

    One of the biggest water pollution problem is created by nitrates resulted from agriculture. This paper is areview aimin to emphasiz the main water pollution problems produced by nitrates in Romania and EU. The excessnitrates can accumulate in soil in several ways. First, manure effluents containing both ammonia and organic forms ofnitrogen. Organic nitrogen can be converted to ammonia in the soil. The ammonia, together with any ammoniafertilizer applied, is converted to nitrate by soil bacte...

  6. Denitration of Uranyl Nitrate Using Tridodecyl Amine

    International Nuclear Information System (INIS)

    Nitrate extraction from uranyl nitrate using extractant tridodecyl amine and paraffin has been carried out. The aim of this research was to prepare uranyl nitrate with low nitrate content (acid deficiency uranyl nitrate/ADUN). ADUN is a raw material for making kernels uranium oxide in a spherical from which cannot easily be broken/cracked. This ADUN was prepared by extracting nitric acid in uranyl nitrate solution with tridodecyl amine (TDA) and paraffin. Nitric acid in uranyl nitrate solution moved into organic phase due to the complex formation with TDA. The aqueous phase was ADUN, it was than analyzed its nitric and uranium contents using titration method. Tree variables were observed, i.e. uranium contents (80-125 g/l), process temperature (50-100 oC) and TDA/Nitrate molar ratio (0.5-1). Experiment results showed that optimum condition accurate at uranium content of 100 g/l, temperature extraction 60-70 oC and TDA to Nitrate molar ratio 0.75-0.80 with an efficiency of 77 %. (author)

  7. Water Pollution with Nitrates from Agricultural Sources

    Directory of Open Access Journals (Sweden)

    FLESERIU A.

    2010-08-01

    Full Text Available One of the biggest water pollution problem is created by nitrates resulted from agriculture. This paper is areview aimin to emphasiz the main water pollution problems produced by nitrates in Romania and EU. The excessnitrates can accumulate in soil in several ways. First, manure effluents containing both ammonia and organic forms ofnitrogen. Organic nitrogen can be converted to ammonia in the soil. The ammonia, together with any ammoniafertilizer applied, is converted to nitrate by soil bacteria in a process called nitrification. Nitrification is importantbecause plants can only use nitrogen as nitrate. It is equally harmful in both, animals and humans.

  8. Photochemistry of Nitrate Adsorbed on Mineral Dust

    Science.gov (United States)

    Gankanda, A.; Grassian, V. H.

    2013-12-01

    Mineral dust particles in the atmosphere are often associated with adsorbed nitrate from heterogeneous reactions with nitrogen oxides including HNO3 and NO2. Although nitrate ion is a well-studied chromophore in natural waters, the photochemistry of adsorbed nitrate on mineral dust particles is yet to be fully explored. In this study, wavelength dependence of the photochemistry of adsorbed nitrate on different model components of mineral dust aerosol has been investigated using transmission FTIR spectroscopy. Al2O3, TiO2 and NaY zeolite were used as model systems to represent non-photoactive oxides, photoactive semiconductor oxides and porous materials respectively, present in mineral dust aerosol. In this study, adsorbed nitrate is irradiated with 254 nm, 310 nm and 350 nm narrow band light. In the irradiation with narrow band light, NO2 is the only detectable gas-phase product formed from nitrate adsorbed on Al2O3 and TiO2. The NO2 yield is highest at 310 nm for both Al2O3 and TiO2. Unlike Al2O3 and TiO2, in zeolite, adsorbed nitrate photolysis to nitrite is observed only at 310 nm during narrow band irradiation. Moreover gas phase products were not detected during nitrate photolysis in zeolite at all three wavelengths. The significance of these differences as related to nitrate photochemistry on different mineral dust components will be highlighted.

  9. High dose potassium-nitrate chemical dosimeter

    International Nuclear Information System (INIS)

    This dosimeter is used to control 10 kGY-order doses (1 Mrad). Nitrate suffers a radiolitic reduction phenomena, which is related to the given dose. The method to use potassium nitrate as dosimeter is described, as well as effects of the temperature of irradiation, pH, nitrate concentration and post-irradiation stability. Nitrate powder was irradiated at a Semi-Industrial Plant, at Centro Atomico Ezeiza, and also in a Gammacell-220 irradiator. The dose rates used were 2,60 and 1,80 KGY/hour, and the given doses varied between 1,0 and 150 KGY. The uncertainty was +-3% in all the range. (author)

  10. Nitrate reductase assay using sodium nitrate for rapid detection of multidrug resistant tuberculosis

    Directory of Open Access Journals (Sweden)

    Maíra Bidart Macedo

    2012-09-01

    Full Text Available We validated the nitrate reductase assay (NRA for the detection of multidrug-resistant Mycobacterium tuberculosis (MDR-TB using sodium nitrate (NaNO3 in replacement of potassium nitrate (KNO3 as nitrate source. NaNO3 is cheaper than KNO3 and has no restriction on use which facilitates the implementation of NRA to detect MDR-TB.

  11. Correlation of anaerobic ammonium oxidation and denitrification

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    The feasibility of the nitrous organic wastewater treated was studied in seven anaerobic sequencing batch reactors(ASBRs)(0 #-6 #) which had been run under stable anaerobic ammonium oxidation (Anammox). By means of monitoring and data analysis of COD, NH4+-N, NO2--N, NO3--N and pH, and of microbial test, the results revealed that the optimal Anammox performance was achieved from 2# reactor in which COD/NH4+-N was 1.65, Anammox bacteria and denitrification bacteria could coexist, and Anammox reaction and denitrification reaction could occur simultaneously in the reactors. The ratio of NH4+-N consumed: NO2--N consumed: NO3--N produced was 1:1.38:0.19 in 0# reactor which was not added glucose in the wastewater. When different ratio of COD and NH4+-N was fed for the reactors, the ratio of NO2--N consumed: NH4+-N consumed was in the range of 1.51-2.29 and the ratio of NO3-N produced: NH4+-N consumed in the range of 0-0.05.

  12. 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.

  13. 15N-ammonium test in clinical research

    International Nuclear Information System (INIS)

    By use of the 15N-ammonium test the liver function is investigated under influence of hormonal contraceptives in women and in liver diseases in children. With the described noninvasive nonradioactive isotope test the ammonia detoxification capability and the urea synthesis capacity of the liver is determined by measuring of the 15N excretion in ammonia and urea in urine after oral administering of 15N-ammonium chloride. The 15N-ammonium test shows a significant influence of the hormonal contraceptives on the liver function and gives diagnostic evidence for liver diseases in children. (author)

  14. Influence of vertical motions on maintaining the nitrate balance in the Black Sea based on numerical simulation

    Science.gov (United States)

    Kubryakova, E. A.; Korotaev, G. K.

    2016-01-01

    The upwelling of deep water associated with the influence of cyclonic wind curl and the difference in the buoyancy of the inflows in the lower and upper water layers is observed in the central part of the Black Sea. The resulting vertical water motions contribute to the transport of ammonium to the upper boundary of the anaerobic zone. In the suboxic zone, ammonium is converted to nitrate via nitrite as a result of the nitrification, and thus it can supply the nitrocline in the water basin. Within the framework of this paper we discuss the effectiveness of this mechanism on the basis of the numerical simulation. The calculations were performed using a one-dimensional physical-biogeochemical model for the upper 600-m sea water layer, which takes into account seasonal variations in atmospheric parameters and vertical motions. The model describes the biological and redox processes in the suboxic zone. We have estimated the contribution of different constituents into the balance of nitrogen compounds in the euphotic water layer. It is shown that ammonium nitrogen coming from the deep water due to vertical water motion plays a significant role in maintaining the balance of nitrates in the central part of the Black Sea.

  15. Global gene expression profiling of Bacillus subtilis in response to ammonium and tryptophan starvation as revealed by transcriptome and proteome analysis.

    Science.gov (United States)

    Tam, Le Thi; Eymann, Christine; Antelmann, Haike; Albrecht, Dirk; Hecker, Michael

    2007-01-01

    The global gene expression profile of Bacillus subtilis in response to ammonium and tryptophan starvation was analyzed using transcriptomics and proteomics which gained novel insights into these starvation responses. The results demonstrate that both starvation conditions induce specific, overlapping and general starvation responses. The TnrA regulon, the glutamine synthetase (glnA) as well as the sigma(L)-dependent bkd and roc operons were most strongly and specifically induced after ammonium starvation. These are involved in the uptake and utilization of ammonium and alternative nitrogen sources such as amino acids, gamma-aminobutyrate, nitrate/nitrite, uric acid/urea and oligopeptides. In addition, several carbon catabolite-controlled genes (e.g. acsA, citB), the alpha-acetolactate synthase/-decarboxylase alsSD operon and several aminotransferase genes were specifically induced after ammonium starvation. The induction of sigma(F)- and sigma(E)-dependent sporulation proteins at later time points in ammonium-starved cells was accompanied by an increased sporulation frequency. The specific response to tryptophan starvation includes the TRAP-regulated tryptophan biosynthesis genes, some RelA-dependent genes (e.g. adeC, ald) as well as spo0E. Furthermore, we recognized overlapping responses between ammonium and tryptophan starvation (e.g. dat, maeN) as well as the common induction of the CodY and sigma(H) general starvation regulons and the RelA-dependent stringent response. Many genes encoding proteins of so far unknown functions could be assigned to specifically or commonly induced genes. PMID:17183219

  16. Evaluation of nitrates in albanian wines

    Directory of Open Access Journals (Sweden)

    Ariola Morina

    2013-05-01

    Full Text Available Nitrates are important compounds in nature but not desirable if they are present in wine at increased amount. The high level of nitrate is attributed to the use of nitrogen fertilizers in the vineyards. Method of the reactive Gries I and Gries II was used for the determination of nitrates in wine. There were analyzed 45 white wines and 55 red wines produced in 2008 – 2010, as well as wines produced from Albanian grape varieties Shesh i Bardhë and Shesh i Zi in 2009 and 2010, as an authentic wines evidence with denominated origin. From the results of analyses was observed that, in 51 % of white wines was found that the content of nitrates were less than 5 mg/l, in 46% of them the nitrates level goes up to 10 mg/l and only in 3 % of them the amount of nitrates is up to 12 mg/l. None of white wine samples have the content of nitrates over 20 mg/l. In this case there is no doubt for water addition during wine preparation. In regards of red wines, in 34% of them the amount of nitrates is up to 5 mg/l, in 30% of them up to 10 mg/l, while in 26% of them the amount of nitrates is 20 mg/l. Only 10 % of red wines have nitrates content over 20 mg/l which raise dubiety for falsified wines where water and sugar is added in the red marc. The level of nitrates in wines with denominated origin was under 20 mg/L.

  17. Nitrate pollution of a karstic groundwater system

    International Nuclear Information System (INIS)

    The Bohemian karst, an extensive karst area formed by Devonian and Silurian limestone, is located SW of Prague. The largest of the karstic springs discharges in the village of Svaty Jan pod Skalou. With about 19 L/s of average discharge, the spring was formerly an important source of good quality drinking water in the ares. Because of increasing agricultural activity after World War II, both shallow and deep water resources, including the karstic systems, have been contaminated by infiltrating nitrates. The nitrate content of the Svaty Jan spring now varies from 40 mg/L to 60 mg/L. To specify the sources of nitrate pollution and collect sufficient data for possible prediction of future development, an extensive study of the spring was initiated in 1994. Flow dynamics, chemical, and isotopic composition (δ18O in water, δ15N in nitrate) are monitored in the spring and precipitation in the recharge area together with possible sources of nitrates (fertilizers, solutes in soil profile). The spring discharge responds to precipitation events very quickly but with a small amplitude and a low variability in δ18O (∼2 per mille). This reflects the large volume of the karstic system that dumps infiltrating precipitation and the low contribution of the direct discharge component. Even more contrasting is the relation between the low variability of nitrate content and periodic changes in δ15N of nitrate (from 5 per mille to 2 per mille). With regard to the specifics of the karstic groundwater system (piston-like flow) two alternative hypotheses of nitrate generation are suggested: (1) different rates of nitrate production in the recharge area and (2) different sources of nitrate localized along the recharge area. To verify the hypotheses, the record of fertilizer applied in the recharge area was studied together with actual nitrate content and its isotopic composition in deep soil profiles. (author)

  18. In situ biostimulation of petroleum hydrocarbon degradation by nitrate and phosphate injection using a dipole well configuration

    Science.gov (United States)

    Ponsin, Violaine; Coulomb, Bruno; Guelorget, Yves; Maier, Joachim; Höhener, Patrick

    2014-12-01

    The main aim of this study was to explore the feasibility of source zone bioremediation by nitrate and nutrient injection in a crude-oil contaminated aquifer using a recirculating well dipole. Groundwater pumped from a downgradient well at a rate of 2.5 m3 h- 1 was enriched with bromide (tracer), nitrate and ammonium phosphate and injected in a well 40 m upgradient. The test was run for 49 days with solute injection, followed by 65 days of dipole operation without solute addition. The resulting bromide breakthrough curve allowed quantifying a first-order leakage coefficient of 0.017 day- 1 from the dipole, whereas from the nitrate data a first-order nitrate consumption rate of 0.075 day- 1 was determined. Dissolved hydrocarbon concentrations including benzene decreased to non-detect in 84 days but experienced important rebounds after ending circulation. Nitrite accumulated temporarily but was consumed entirely when solute injection stopped. The mass balance calculations revealed that about 83% of the nitrate was used for hydrocarbon degradation, with the remaining being used for oxidation of reduced sulfur. A reactive transport model was used for the delineation of the treated zone. This model suggested that denitrification influenced flow and transport in the dipole. It is concluded that successful promotion of denitrifying hydrocarbon degradation is easily obtained in this aquifer and enables to abate dissolved concentrations, and that dipole configuration is a good option.

  19. Study of the nitration of poly(4,4'-diphenylether-1,3,4-oxadiazole) to gas permeation

    International Nuclear Information System (INIS)

    This work is a systematic modification of the poly(4,4'-diphenylether-1,3,4-oxadiazole), POD-DPE, through of the substitution of atoms of hydrogen for NO2 groups, in aromatic rings. The presence of these groups increases the spacing among the polymer chains and decreases the packing, that promotes a larger free volume for diffusion of the permeable molecules. The nitration of POD-DPE was accomplished using N-methyl-pyrrolidine as solvent, ammonium nitrate and trifluor acetic anhydride as nitrating agent and triethylamine to finish the reaction. The influence of reaction conditions was investigated by characterization of the modified polymer. The characterization was carried out by thermal analysis (TMA and TGA), viscosity, conductivity, NMR and permeability. The viscosity analysis showed that the chemical stability of the nitrate material decreased. The results also indicated that the nitration of the aromatic rings takes to a significant reduction in Tg and little affects the polymer degradation temperature. The characterization by gas permeation also presented an increase in the permeability and selectivity of the polymer. (author)

  20. Nitrate uptake, nitrate reductase distribution and their relation to proton release in five nodulated grain legumes.

    Science.gov (United States)

    Fan, X H; Tang, C; Rengel, Z

    2002-09-01

    Nitrate uptake, nitrate reductase activity (NRA) and net proton release were compared in five grain legumes grown at 0.2 and 2 mM nitrate in nutrient solution. Nitrate treatments, imposed on 22-d-old, fully nodulated plants, lasted for 21 d. Increasing nitrate supply did not significantly influence the growth of any of the species during the treatment, but yellow lupin (Lupinus luteus) had a higher growth rate than the other species examined. At 0.2 mM nitrate supply, nitrate uptake rates ranged from 0.6 to 1.5 mg N g(-1) d(-1) in the order: yellow lupin > field pea (Pisum sativum) > chickpea (Cicer arietinum) > narrow-leafed lupin (L angustifolius) > white lupin (L albus). At 2 mM nitrate supply, nitrate uptake ranged from 1.7 to 8.2 mg N g(-1) d(-1) in the order: field pea > chickpea > white lupin > yellow lupin > narrow-leafed lupin. Nitrate reductase activity increased with increased nitrate supply, with the majority of NRA being present in shoots. Field pea and chickpea had much higher shoot NRA than the three lupin species. When 0.2 mM nitrate was supplied, narrow-leafed lupinreleased the most H+ per unit root biomass per day, followed by yellow lupin, white lupin, field pea and chickpea. At 2 mM nitrate, narrow-leafed lupin and yellow lupin showed net proton release, whereas the other species, especially field pea, showed net OH- release. Irrespective of legume species and nitrate supply, proton release was negatively correlated with nitrate uptake and NRA in shoots, but not with NRA in roots. PMID:12234143