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This article in SSSAJ

  1. Vol. 41 No. 1, p. 47-50
    Received: May 24, 1976
    Accepted: Sept 8, 1976

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Chemical Reduction of Nitrite and Nitrous Oxide by Ferrous Iron1

  1. J. T. Moraghan and
  2. R. J. Buresh2



Little is known about the reduction of NO2- and N2O by Fe2+ in the pH range from 6 to 8, a range of importance in many natural environments. Reduction of 25 mg NO2--N (approximate concentration=25 ppm) and 5 mg N2O-N in a distilled-water medium containing 800 mg Fe2+ with a helium atmosphere in the presence and absence of Cu2+ at pH 6 and 8 was studied at 26°C. Reduction of NO2- to N2O (the principal product), N2 and NH4+ was rapid and quantitive at pH 8 and not greatly affected by Cu2+. However, addition of Cu2+ decreased the mole ratio of N2O to N2 in the evolved gas mixture from 4.2 to 3.1. Reduction of NO2- at pH 6 was incomplete, but was favored by Cu2+ addition. Nitrous oxide was the dominant reduction product at this pH value. Small quantities of NO accumulated at pH 6.

Irrespective of Cu2+ addition, N2O was stable in the Fe2+ medium at pH 6. In the pH 8-system in the presence of Cu2+ 84% of the N2O was reduced to N2. Nitrous oxide was relatively stable at pH 8 in the absence of Cu2+. Small quantities of H2 accumulated in the atmospheres of vessels containing the pH 8, plus Cu2+ N2O − N treatment. No H2 accumulated in the NO2- series of treatments.

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