Showing papers on "Ammonia published in 1973"

Gas Phase Solvation of the Ammonium Ion by NH3 and H2O and Stabilities of Mixed Clusters NH4+ (NH3)n(H2O)w

Abstract: The gas phase equilibriaand those leading to mixed clusters likewere measured with a pulsed electron beam high pressure ion source mass spectrometer. The ion source contained pure ammonia or mixtur...

The effect of pellet size on the ammonia loss from urea applied to forest soil

Abstract: Using diluted phosphoric acid- and glycerol-treated polyurethane plastic foam discs as static ammonia absorbers, the extent of ammonia loss from applied urea was determined on forest soil under field conditions. The investigation, which primarily involved a comparison of urea materials of two different pellet sizes (2–4 mg and 2060 mg urea per pellet, respectively), extended over a period of 28 days. The urea was applied to the soil surface at a rate of 200 kg N per hectare. It was found that the gaseous ammonia loss from the large-pellet urea (tablets) was markedly lower than that from the small-pellet urea during the first two weeks of exposure. On extending the observation period to four weeks, this difference in cumulative ammonia loss decreased successively. After 28 days' exposure, at a daily mean temperature of 13°C, the volatile loss amounted to 20 and 22 per cent, respectively. An addition of 5% (w/w) of a solution of concentrated orthophosphoric acid, or a fine-crystalline ortho-boric acid to the large-pellet urea, resulted in a reduction of the loss to half the value. The possibilities of controlling the ammonia loss from urea by combining the large pellet size with the addition of urease inhibitors are discussed. re]19721012

Na+/NH4+, Na+/H+ Exchanges and NH3 Movement Across the Gill of Carassius Auratus

Abstract: 1. Sodium exchange, ammonia excretion and H + ion movement across the gill were measured in sodium-depleted Carassius auratus . Sodium uptake and ammonia excretion are considerably enhanced by sodium depletion. In this respect sodium-depleted fish behave as ammonia-loaded fish. 2. A decrease of the external pH by one unit results in a 50-60% decrease in both influx and efflux of sodium. A transient augmentation of the rate of ammonia excretion is observed upon acidification, suggesting an increased permeability of the gill to the free-base form of ammonia. 3. The ionic balance sheet of the movements of the monovalent ions across the gill was drawn up when a permeant co-ion for sodium was absent from the external medium. In both acid and alkaline media the ionic balance was achieved in accordance with the law of electroneutrality of external and internal solutions. 4. Net Na + uptake was only found to be correlated to NH 4 + excretion if H + ion movements across the gill were taken into account. 5. Ammonia-gradient experiments were performed to test the ability of the gill to excrete ammonia against a gradient of ammonia partial pressure. Ammonia excretion is independent of this gradient in alkaline media when sodium ions are present. In these conditions ammonia moves in the ionic form. In acid media, with Na present in the external medium, ammonia movement is correlated with the p NH 3 gradient but uphill movement still occurs. Ammonia moves in both the free-base and the ionized forms. In the absence of external sodium, movements of ammonia obey the law for passive transfer and ammonia moves exclusively in the free-base form, even though the external medium is alkaline.

Ammonia-stable Y zeolite compositions

Abstract: Highly active, hydrothermally stable and ammonia-stable Y zeolite compositions are disclosed, which compositions are useful as adsorbents, hydrocarbon conversion catalysts, and as acidic supports for catalytic metals The stabilized Y zeolite composition is prepared from a sodium Y zeolite by a novel sequence of: (1) partial exchange of ammonium ions for sodium ions, (2) steam calcination under controlled conditions of time, temperature and steam partial pressure, and (3) further ion exchange of ammonium ions for sodium ions to reduce the final Na2O content to below about one weight-percent

Assessment of volatilization loss of ammonia from surface-applied urea on forest soil by N15 recovery

Abstract: Using vertically isolated micro-plots the isotopic recovery technique was tested for assessing the extent of ammonia volatilization loss from N15-labelled urea applied on the forest floor (Pinus silvestris L.). The size of the ammonia loss was obtained as a difference between the amounts of labelled urea N added and the amounts of labelled N recovered in the soil profile after 13, 31, and 39 days's exposure, respectively. Urea materials of two different pellet size were used: granulated small pellets (280 pellets per gram) and tablets (2.06 g each). The nitrogen application rate was 200 kg N per hectare.

Method for Removing Nitric Oxide from Combustion Gases

Abstract: This invention relates to a method for removing nitric oxide, in the presence of sulfur dioxide, from combustion flue gases containing nitric oxide, oxygen, carbon monoxide, carbon dioxide water vapor, unburned fuel, particulate matter, and sulfur dioxide by mixing ammonia with the flue gas, the amount of ammonia, by volume being at least equal to the volume of nitric oxide and contacting the resulting mixture of flue gas and ammonia with a catalyst selected from the group consisting of platinum group metals such as platinum, and transition metals such as vanadium, molybdenum, nickel, copper, cobalt, chromium, oxides thereof and mixtures thereof, the temperature of the catalyst being, in the case of platinum, between 525 DEG F. and 700 DEG F. and in the case of the other catalysts, between 500 DEG F. and 1,000 DEG F. The preferred support for the catalyst is a monolithic support structure, such as a corregated ceramic structure.

Nitrogen constituent analysis

Abstract: A unitary system is provided with separate channels for detecting and analyzing different types of nitrogen-containing compounds, particularly those which may be encountered in waste treatment or in pollution control or in food product analysis. The channels are so designed that an injected sample is acted upon in gaseous or suspended form, with reaction products thereof carried through the system by carried gas and ultimately converted to nitric oxide for analysis in a nitric oxide analyzer. Each channel contains reaction columns packed with a suitable substance. There is a total combined nitrogen channel in which a sample is first catalytically oxidized to form nitric oxides. In a nitrite-nitrate nitrogen channel a sample is first treated to form nitrites and injected into a reaction column packed with an acidifying substance and in an ammonia nitrogen channel the sample is injected into a reaction column packed with an alkalyzer before proceeding to a reaction column packed to catalytically oxidize the resulting ammonia to nitrogen dioxide and nitric oxide. In a modified embodiment a suitably pretreated sample suspected of cyanide content may also ultimately be converted to nitric oxide for analysis.

Kinetics of nitric oxide formation incombustion processes

Abstract: Recent investigations of nitric oxide formation in combustion are reviewed with the objectiveof obtaining mechanistic information on nitric oxide formation from atmospheric (molecular) nitrogen and from nitrogen-containing compounds in the fuel. Comparison of existing data on formation of nitric oxide from atmospheric nitrogen with results from detailed kinetics calculations shows that, for the most part, the experimental observations are consistent with a three-reaction mechanism for nitric oxide chemistry if radical concentrations and temperature during combustion are correctly evaluated. The principal nitric oxide formation reactions are O+N2”NO+N, (1) N+O2”NO+O; (2) however, N+OH”NO+H, (3) can be of importance in fuel-rich mixtures. Experimental studies of the formation of nitric oxide from nitrogen-containing compounds indicate that the formation rates are rapid, occurring on a time-scale comparable to that of the combustion reactions. A simplified mechanism for conversion of nitrogen-containing compounds to nitric oxide is proposed. In this mechanism, a partial equilibrium approximation is used to relate the maximum nitric oxide concentration in the combustion zone to the maximum radical concentrations. The proposed mechanism adequately models nitric oxide formation in the shock-induced combustion of lean hydrogen-oxygen mixtures containing small amounts of ammonia.

Factors Affecting Ammonia Removal by Clinoptilolite

Abstract: The effect of ammonium ion concentration, flow rate, and temperature on ammonium ion removal from solution by the selective ion exchange resin, clinoptilolite, were investigated. Columns were operated at flow rates of 26.67 and 13.33 bed volumes per hour (BV/hr), ammonium ion concentrations of 70 mg per L as N and 14 mg per L as N and temperatures of 12° C and 2° C. Performance was measured as ammonia capacity and liquid volume treated to breakthrough. Initial ammonium ion concentration has the greatest influence on the capacity of clinoptilolite. Excellent agreement between observed ammonia capacities and those predicted from a theoretical equilibrium model suggested that the model could provide preliminary assessments of wastewater treatment with clinoptilolite. The initial ammonium ion concentration had a significant effect on the volume of liquid treated to breakthrough. Flow rate and temperature did not.

Effect of nitrate, ammonia and nitrogen starvation on the regulation of nitrate reductase in Cyanidium caldarium

Abstract: Cells of Cyanidium caldarium grown with ammonia or ammonium nitrate as nitrogen source do not contain appreciable nitrate reductase activity. The alga develops the capacity to synthesize the enzyme when it is transferred from the ammonium medium to a nitrogen-free medium. Nitrate is not needed as an inducer and no enhancement in the rate of enzyme synthesis is observed when it is present. By contrast, whereas the synthesis of the enzyme in nitrogen-free medium proceeds at an increasing rate, in the nitrate medium it attains a stationary level after a short time.

Recovery of residual ammonia from weak aqueous solutions thereof

Abstract: AMMONIA IS RECOVERED FROM A WASTE, LIQUID EFFLUENT COMPRISING A WEAK AMMONIUM AQUEOUS SOLUTION CONTAIN ING AMMONIA AND/OR AMMONIUM CARBAMATE OR AMMONIUM CARBONATE BY STRIPPING THE SOLUTION WITH STREAM AND AN INERT GAS IN A FRACTIONATOR AT SPECIFIED CONDITIONS. SUBSTANTIALLY ALL OF THE AMMONIA IS RECOVERED IN AN OVERHEAD GASEOUS PRODUCT AND A BOTTOMS LIQUID WHICH IS ESSENTIALLY CONDENSATE SUBSTANTIALLY FREE OF AMMONIA IS ALSO RECOVERED.

Organ uptake and blood pH and concentration effects of ammonia in dogs determined with ammonia labeled with 10 minute half‐lived nitrogen 13

Abstract: u Malfunction of the nervous system may occur in association with liver disease. Because blood ammonia concentration is often elevated during liver disease, the effects o n the brain of this cxposurc to ammonia are suspected of bcing related to the neurologic symptoms. This report is designed to further substantiate and add to blood ammonia-brain ammonia relationship information by providing the results of monitored radioactivity in the brain, blood and liver of dogs after intravenous injection of ammonia labeled with nitrogen 13 ( ’ N ) . T h e 3 N label of the ammonia ( I NFI4+/I3 NH,) is cyclotron produced, has a half-life of 10 minutes, decays by positron emission, and can be detected externally by counting the S 1 1 keV annihilation radiation. The relative relationship of ammonia concentration in brain, blood and liver was siniultancously studied during ( I ) changes in blood p l l and (2 ) changes in blood ammonia concent r a tio n . * Fvidence indicates that most ammonia in blood is in the ionized ammonium (NH4+) form and that the amount of the unionized gaseous form ( N H 3 ) is small in comparison and dependent on its dissociation constant as a

The Use of an Ammonium Selective Electrode for the Automatic Determination of Ammonia in Boiler Feed-Waters

Abstract: An automatic potentiometric method for the determination of ammonia in boiler feed-waters is presented. An ammonium selective membrane electrode of the neutral carrier type was used as sensor-electrode. The accuracy and reproducibility were very good. The method allows a sample rate of 30 samples an hour.

Process for the removal of sulfur from battery wrecker material using ammonium carbonate solution

Abstract: A process for the conversion of waste battery scrap materials containing lead sulfate comprising an initial leaching operation to convert such lead sulfate to lead carbonate while at the same time converting the aqueous ammonium carbon solution to ammonium sulfate. Such is followed by filtration to thus separate soluble ammonium sulfate from the insoluble lead carbonate. The ammonium sulfate is then suitably crystallized resulting in a commercial product, namely, a useful fertilizer compound. The lead carbonate referred to in the foregoing is decomposed by application of heat to produce lead oxide and carbon dioxide, the latter then being reacted with aqueous ammonia to produce more ammonium carbonate solution for another beginning leach cycle. The advantages of the system reside in the reduction of emission of noxious sulfur oxides (SOx) in an amount from at least about 80 to 90 percent while at the same time producing a useful commercial product, ammonium sulfate.

Continuous process for scrubbing out hydrogen sulfide and ammonia from coke oven gas

Abstract: A continuous process is provided for scrubbing hydrogen sulfide and ammonia from coke oven gases by selectively scrubbing the hydrogen sulfide using aqueous ammonia, then distilling the hydrogen sulfide again from the wash liquor combining the ammonia directly with acids or certain acid salts, e.g., sulfuric acid or ammonium bisulfate, liberating the combined ammonia therefrom by decomposition, and then recycling the released ammonia to the hydrogen sulfide scrubber, thereby increasing the ratio of ammonia to hydrogen sulfide therein. A preferred absorbent for ammonia is monoammonium phosphate.

Production of hydrogen fluoride

Abstract: Hydrogen fluoride is produced from hydrofluosilicic acid. The hydrofluosilicic acid is reacted with ammonia. An aqueous solution of ammonium fluoride thus produced is fed with partly recycled alkali metal fluoride to a continuously operated reactor where a bifluoride of the alkali metal is formed in aqueous solution. Reaction mixture is continuously withdrawn and solid alkali metal bifluoride crystallized therefrom. The mother liquor is recycled to the reactor. The solid alkali metal bifluoride is decomposed by heat to produce hydrogen fluoride and solid alkali metal fluoride. The alkali metal fluoride is recycled to the reactor.