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Clays and Clay Minerals

, Volume 44, Issue 5, pp 599–608 | Cite as

Reduction of Nitrate By Fe2+ in Clay Minerals

  • Vibeke Ernstsen
Article

Abstract

In the 12 km2 catchment area of Syv creek, Denmark, moderate to high concentrations of nitrate (NO3) occurred in the upper part of the oxidized zone (oxic-I), but dropped within the lower suboxic part (oxic-II), to below the detection limit in the unoxidized zone. Structural Fe2+ in the clay minerals made up 10 to 12% of the Fe in the oxidized zone and increased to approximately 50% in the unoxidized zone. Concurrent with changes in the distribution of structural Fe2+ the clay mineral constituents changed. Vermiculite was typically found in the oxidized zone whereas chlorite was found in the unoxidized zone only. A conversion of illite and chlorite into vermiculite seems to take place. A significant correlation between NO3 and the amount of reduced Fe2+ in the suboxic (oxic-II) zone, indicates that primary structural Fe2+ in the clay minerals is the reductant in a NO3 reduction process.

Key Words

Chlorite Clayey till Exchangeable ferrous iron Illite Mössbauer Nitrate Oxidized Structural ferrous iron Unoxidized Vermiculite Weichselian X-ray 

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Copyright information

© The Clay Minerals Society 1996

Authors and Affiliations

  • Vibeke Ernstsen
    • 1
  1. 1.Geological Survey of Denmark and GreenlandCopenhagen NVDenmark

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