Nitrogen

8 Key excerpts on "Nitrogen"

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  Water Quality Modeling

  Rivers, Streams and Estuaries

  • R. Manivanan(Author)
  • 2021(Publication Date)
  • NIPA GENX Electronic Resources and Solutions Pvt Ltd.

    (Publisher)

  - 175 - 12.1 Introduction-Nitrogen Nitrogen is a chemical element which has the symbol N and atomic number 7. Elemental Nitrogen is a colourless, odourless, tasteless and mostly inert diatomic gas at standard conditions, constituting 78.1% by volume of Earth’s atmosphere. Nitrogen is a constituent element of all living tissues and amino acids. Many industrial important compounds, such as ammonia, nitric acid, and cyanides are made up of Nitrogen. 12.1.1 History Nitrogen (Latin Nitrogenium, where nitrum (from Greek nitron) means “native soda”and genes means “forming”) is formally considered to have been discovered by Daniel Rutherford in 1772, who called it noxious air or fixed air. That there is a fraction of air that did not support combustion is well known to the late 18th century. Argon was discovered when it is noticed that Nitrogen from air is not identical to Nitrogen from chemical reactions. Compounds of Nitrogen were known in the Middle Ages. The alchemists knew nitric acid as aqua fortis (strong water). The mixture of nitric and hydrochloric Nitrogen and Phosphorus Modeling Chapter 12 176 WATER QUALITY MODELING acids is known as aqua regia (royal water), celebrated for its ability to dissolve gold (the king of metals). The earliest industrial and agricultural applications of Nitrogen compounds involved uses in the form of saltpeter (sodium- or potassium nitrate), notably in gunpowder, and much later, as fertilizer, and later still, as a chemical feedstock. Solid Nitrogen ice in a small plastic beaker with melting liquid flowing off. The Nitrogen has been frozen by immersion in liquid helium. Nitrogen gas is acquired for industrial purposes by the fractional distillation of liquid air, or by mechanical means using gaseous air. Commercial Nitrogen is often a byproduct of air-processing for industrial concentration of oxygen for steel making and other purposes.

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  Biogeochemistry of Wetlands

  Science and Applications

  • K. Ramesh Reddy, Ronald D. DeLaune, Patrick W. Inglett(Authors)
  • 2022(Publication Date)
  • CRC Press

    (Publisher)

  8  Nitrogen

  DOI: 10.1201/9780429155833-8

  8.1 Introduction

  Nitrogen is an essential macroelement for all living organisms in the biosphere. As a major component of proteins and nucleic acids, Nitrogen is one of the most limiting nutrients regulating the productivity in terrestrial, wetland, and aquatic ecosystems. Like carbon, Nitrogen exists as a complex mixture of both organic and inorganic compounds. The relative proportion of each form depends on the sources of Nitrogen and the system processes affecting the relative rates and turnover times of these compounds. Organic Nitrogen includes both dissolved and particulate forms, whereas inorganic Nitrogen (ammonium N, nitrite N, and nitrate N) is mainly present in dissolved forms. Particulate forms are removed through settling and burial, whereas the removal of dissolved forms is regulated by various biogeochemical reactions functioning in soil and the overlying water column. The relative rates of these processes are affected by physicochemical and biological characteristics of the soil and water column and the organic substrates present. Although the basic Nitrogen transformations in terrestrial, wetland, and aquatic ecosystems are the same, relative rates and storages are different in each of these ecosystems.

  8.2 Forms of Nitrogen

  Nitrogen, with its symbol as N, has an atomic number of 7. The isotopes of Nitrogen have mass numbers ranging from 12 to 18. Nitrogen isotopes 14 and 15 are stable with natural abundance of 99.64% and 0.366%, respectively. However, there are five other isotopes (N-12, N-13, N-16, N-17, and N-18), which are unstable and radioactive. Nitrogen, which is required by all organisms for basic processes of life, is found in nature in two basic forms: inorganic and organic.

  8.2.1 Inorganic Nitrogen

  • DiNitrogen (N
    2
    ): It is the most common form of Nitrogen and makes up to 78% of the atmosphere. It is colorless at room temperature, very stable, and slightly soluble in water. High activation energy is required to break the N2 triple bond. Biologically, this triple bond is broken by organisms capable of fixing N2 . Industrial fixation of N2

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  The Elements of Environmental Pollution

  • John Rieuwerts(Author)
  • 2017(Publication Date)
  • Routledge

    (Publisher)

  3  Nitrogen Environmental reservoirs and chemical forms Atmosphere

  Most of the Nitrogen (N) within the Earth system is contained in the atmosphere. More than 99.9% of atmospheric N is present as Nitrogen gas (N2 ), which comprises 78% of the atmosphere by volume. Its atmospheric abundance is attributable to its stability: the triple covalent bond between the two Nitrogen atoms in the N2 molecule requires a large energy input to be broken (Fig. 3.1 ). For this reason, photolysis of N2 molecules to monatomic N occurs only in the upper atmosphere, in the presence of sufficiently strong short-wave radiation.

  Other Nitrogen-containing gases are present in trace amounts, collectively accounting for less than 0.001% of the atmosphere by volume. Of these trace gases, nitrous oxide (N2 O), a greenhouse gas, is by far the most abundant, mainly because it is relatively stable and has an atmospheric lifetime of >100 years. The other main N gases are more short-lived in the atmosphere: they include ammonia (NH3 ), nitric oxide (NO) and Nitrogen dioxide (NO2 ). The chemistry of the latter two oxides of N is closely linked and they are collectively known as ‘NOX ’. Other atmospheric components include:

  (i)	nitric acid (HNO3 ), which is present as a gas or within aerosols/cloud droplets;
  (ii)	ammonium nitrate (NH4 NO3 ), which is produced via reaction of NH3 and HNO3 (equation 3.1 ); it occurs either as a solid (as shown in the equation), forming cloud condensation nuclei, or as an aqueous species;

  (iii)

  amines (derivatives of ammonia), where one or more of the H atoms in NH3 is replaced by an organic group such as an aromatic or an alkyl (e.g. methylamine, CH3 NH2 and trimethylamine, (CH3 )3 -N) or by elements such as chlorine (e.g. chloramine, NClH2 ).

  Lithosphere

  Nitrogen is present at high concentrations in the interior of the Earth, but it is not abundant in the near-surface rocks of the Earth’s crust, in contrast to the other major elements. It is present in fossil fuels (up to 2% of the contents of coal, for example) and organic-rich shales, reflecting the role of N in the biosphere. It is distributed finely, as NH4 , in components of igneous rocks, such as feldspars and micas. Evaporite nitrate formations are rare, but a notable deposit of sodium nitrate exists, as the mineral nitratine, in the Atacama Desert of Chile and part of Peru (Fig. 3.2 ); deposits of the highly soluble nitratine are found in smaller quantities in other arid environments, including Death Valley, USA and the deserts of Egypt. In soils, Nitrogen is present in organic matter and, in a less-available form, as adsorbed NH4

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  Dictionary of Energy

  • Cutler J. Cleveland, Christopher G. Morris(Authors)
  • 2014(Publication Date)
  • Elsevier

    (Publisher)

  Nitrogen dioxide Chemistry. NO 2 , a compound of Nitrogen and oxygen formed by the oxidation of nitric oxide (NO), produced by the combustion of solid fuels. It is a major air pollutant, playing a key role in atmospheric reac-tions that produce ground-level ozone, a major component of smog. It is also a precursor to nitrates, which contribute to increased respirable particle levels in the atmosphere. Nitrogen fixation Earth Science. the con-version of atmospheric Nitrogen into chemical compounds, such as ammonia, that can be used by green plants in the formation of proteins. One form of this process is biological fixation, which is carried out by certain bacteria that are present on the nodules of the plants. Two other forms are atmospheric fixation (the energy of lightning) and industrial fixation (human activities such as the burning of fossil fuels and fertilizer pro-duction and use). Nitrogenous Chemistry. containing or utilizing Nitrogen. Nitrogen oxide Chemistry. NO x , the generic term for a group of highly reac-tive gases, all of which contain Nitrogen and oxygen in varying amounts; many are colorless and odorless, although one common pollutant, Nitrogen dioxide (NO 2 ) can be seen along with particles in the air as a reddish-brown layer over many urban areas. Nitrogen oxides form when fuel is burned at high temperatures, in motor vehicles, electric utilities, and other industrial, commercial, and residen-tial sources. The components of NO x are acid rain precursors and also participate in atmospheric ozone chemistry. Nitrogen rejection unit Oil & Gas. a facility in which an entire natural gas stream is liquefied to remove impuri-ties, then regasified and transported as pipeline-quality gas. nitroglycerine Materials. a toxic, yellow, viscous liquid that is slightly soluble in water and soluble in alcohol; it freezes at 13.1°C and explodes at 218°C; used as an explosive and rocket fuel.

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  Environmental Sampling and Analysis

  Lab Manual

  • Maria Csuros(Author)
  • 2018(Publication Date)
  • Routledge

    (Publisher)

  23

  NITROGEN COMPOUNDS AND ANALYSIS OF AMMONIA NITROGEN

  23.1 Nitrogen COMPOUNDS AND Nitrogen CYCLE

  Nitrogen compounds are members of the inorganic nutrient group (Nitrogen-and phosphorus-containing compounds), and the wide variety of forms of Nitrogen in environmental samples have great interest. Major pollution sources of nutrients are surface and subsurface agricultural and urban drainage, animal waste runoff, as well as domestic and industrial waste effluents.

  Nitrogen gas makes up 78% (v/v) of dry air. Nitrogen forms part of many organic molecules, usually amino acids (the building block of proteins) and the genetic materials RNA (ribonucleic acid) and DNA (deoxyribonucleic acid). However, plants and animals cannot use Nitrogen in the form of atmospheric Nitrogen (N2 ). To be usable, it must first be converted to ammonia (NH3 ) and nitrate (NO3 ). The conversion of atmospheric Nitrogen to usable forms of Nitrogen is called Nitrogen fixation, which is associated with bacterial activity. One Nitrogen-fixing bacteria, called Rhizobium, invades the roots of leguminous species (peas, beans, alfalfa, clover, and others). The roots form tiny nodules where the Nitrogen fixation takes place. Bacteria species, as Azotobacter, are ready to fix atmospheric Nitrogen directly in the soil. The fixed Nitrogen is taken by plants and then synthesized to amino acids, proteins, DNA, and RNA. Animals, in turn, receive the needed Nitrogen by eating plants and other animals.

  Nitrogen-rich wastes from plants and animals will be decomposed by certain types of bacteria and converted to ammonia (NH3 ). This process is called ammonification.

  Ammonia oxidizes to nitrite (NO2 ) by oxidizing bacteria species Nitrosomonas, and the nitrite oxidizes to nitrate (NO3 ) by other oxidizing bacteria called Nitrobacter. The process is called nitrification. Nitrates decompose to nitrites, convert into a gas, nitrous oxide (N2 O), by bacterial activity (Pseudomonas and others), and are released into the atmosphere. The process called denitrification

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  Chemistry of the Natural Atmosphere

  • Warneck(Author)
  • 1988(Publication Date)
  • Academic Press

    (Publisher)

  Chapter The better-known among a great number of Nitrogen compounds in the atmosphere are ammonia, several Nitrogen oxides, and nitric acid. These gases are discussed in the present chapter. NH3, N20, and to some extent NO and NO2 as well are natural constituents of air arising as an outflow from the biosphere. Although atmospheric chemistry views the biosphere merely as a source (or sink) of trace gases, it will be helpful for the subsequent discussions to give initially a summary of the biochemical processes that are responsible for the release of Nitrogeneous volatiles from soil and aquatic environs. The individual pathways of elemental Nitrogen in the biosphere and in the atmosphere represent portions of a larger network of fluxes involving all geochemical reservoirs. This aspect will be considered in Section 12.3 from a different viewpqint. 9.1 Biochemical Processes The following description of the biological Nitrogen cycle emphasizes the production of volatile compounds that can escape to the atmosphere. Delwiche (1970) has presented a popular account of the Nitrogen cycle. A compilation of review articles edited by Clark and Rosswall(l981) contains many more details and numerous literature citations. Textbooks on micro- biology provide additional information. 422 9.1 BIOCHEMICAL PROCESSES 423 Figure 9-1 shows pathways of biological Nitrogen utilization for the soil-plant ecosystem. With appropriate modifications, the scheme may also be applied to aquatic ecosystems. Nitrogen enters the biosphere largely by way of bacterial Nitrogen fixation, a process by which N2 is reduced and incorporated directly into living biomass. A limited number of bacteria are fitted with the special enzyme system necessary for this task. Examples include phototrophic Cyanobacteria in natural waters, heterotrophs like Clostridia and Azobacter in the soil, and symbionts associated with plants, such as Rhizobia living in the root nodules of legumes.

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  Chemistry for the 21st Century

  • Ehud Keinan, Israel Schechter(Authors)
  • 2008(Publication Date)
  • Wiley-VCH

    (Publisher)

  The significance of N is indicated by the fact that it is an important constituent of proteins, nucleic acids, porphyrins, and alkaloids. In the soil, soil organic matter (SOM) acts as a storehouse and supplier of N to plant roots and microorganisms: 95 % and more of the total soil N is closely associated with SOM. [l] While a considerable amount of research has been done on soil N over the years, most of this work has been limited to qualitative and quantitative determinations of proteinaceous materials, amino acids, and ammonia. This leaves about one-third to one-half of the soil N unidentified and poorly understood, so that there is a need for more research and information in this area. The objective of this paper is to present an up-to-date account of what we know about the chemistry of soil N. The first part of this paper will deal with the distribu- tion in different soils of proteinaceous materials, amino sugars, and ammonia, while the second part will focus on recent data on the identities and roles of hetero- cyclic N compounds, which also appear to play a significant role in supplying N to plant roots and microbes. 8.2 Nitrogen Fixation and Ensuing Reactions Only a few soil microorganisms have the ability to use molecular N,; all remaining living organisms require combined N for carrying out their life activities. Therefore, in the context of this discussion, the role of Nitrogen-fixing bacteria, which can fix N2 and reduce it to ammonia, becomes very important. Of special interest at this point are the following four reactions: 118 8 The Chemistry ofNitrogen in Soils 1. Nitrogen (N2) in the atmosphere + organic N (Nitrogen fixation) 2. Organic N -+ ammonia (mineralization or ammonification) 3. Ammonia + organic N (immobilization or assimilation) 4. Nitrate --$ organic N (nitrate assimilation or immobilization) Nitrogen fixation (reaction 1) involves the reduction of elemental N2 to the -3 oxidation state in NH3.

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  Chemistry

  With Inorganic Qualitative Analysis

  • Therald Moeller(Author)
  • 2012(Publication Date)
  • Academic Press

    (Publisher)

  Nitrogen is a colorless, odorless, and nontoxic gas. Like oxygen it is difficult to liquefy. It is less soluble in water than is oxygen, dissolving to the extent of 23.2 ml/liter of water at 0°C and 1 atm pressure.

  The most common oxidation states for Nitrogen are -3, +3, and +5. It can, however, be found in all of the oxidation states from -3 to +5. A summary of these states is given in Table 22.3 along with the names and formulas of compounds corresponding to each state.

  TABLE 22.3 Oxidation states of NitrogenThe common names of the Nitrogen oxides are given in parentheses.

  Oxidation state	Compounds
  -3	Nitrides, e.g., Li3 N Ammonia, NH3 Ammonium salts, NH4 X
  -2	Hydrazine, N2 H4
  -1	Hydroxylamine, NH2 OH
  +1	Nitrogen(I) oxide, N2 O (nitrous oxide)
  +2	Nitrogen(II) oxide, NO (nitric oxide)
  +3	Nitrogen(III) oxide, N2 O3 Nitrous acid, HNO2 Nitrites, e.g., NaNO2
  +4	Nitrogen(IV) oxides, NO2 (Nitrogen dioxide), N2 O4 (Nitrogen tetroxide)
  +5	Nitrogen(V) oxide, N2 O5 (Nitrogen pentoxide) Nitric acid, HNO3 Nitrates, e.g., NaNO3

  Common oxidation states of N: -3, +3, +5

  22.3 Sources, preparation, and uses of Nitrogen

  Gaseous molecular Nitrogen constitutes about 78% of the atmosphere by volume, and this is the major source of Nitrogen, which is prepared industrially by the fractional distillation of liquid air (Section 6.4 ). Unless purified, Nitrogen from this source is contaminated with small amounts of oxygen and some of the noble gases.

  In combined form, Nitrogen occurs to a small extent in the Earth’s crust, mainly as sodium nitrate, NaNO3 , and potassium nitrate, KNO3 . The major deposits of sodium nitrate are in Chile in South America, and sodium nitrate is known as Chile saltpeter. Potassium nitrate is known as saltpeter. The word “saltpeter” is thought to derive from the Latin petrus

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