Enhancement of nitrate reduction in Fe0-packed columns by selected cations

Yong H. Huang, Tian C. Zhang

Research output: Contribution to journalArticle

20 Scopus citations

Abstract

Tests were conducted in Fe0-packed columns to investigate the effects of adding selected cations on nitrate removal by Fe0. Due to a rapid passivation of Fe0, only negligible nitrate was reduced in the columns without adding the selected cation. However, adding certain selected cations (Fe2+, Fe3+, or Al3+) in feed solution can significantly enhance nitrate reduction. Extending hydraulic retention time (HRT) increased nitrate removal by the columns, but the increase was not linearly proportional to HRT. Decreases in columns' hydraulic conductivity (K) were monitored in an 8 month operating period. A modest decrease in K was recorded in the upper and the middle section of the media bed, whereas a significant decrease in K occurred in the inlet section. X-ray diffraction analyses indicate that magnetite (Fe3O4) was the dominant species of the iron corrosion products in the entire height of the column media under anoxic and other test conditions. In the inlet section, however, lepidocrocite and goethite were also identified. Cementation was found to occur only in the inlet section, suggesting that lepidocrocite and goethite, rather than magnetite, might be responsible for the cementation and thereby cause the hydraulic clogging. The magnetite coating would not necessarily cause clogging of the media. Journal of Environmental Engineering

Original languageEnglish (US)
Pages (from-to)603-611
Number of pages9
JournalJournal of Environmental Engineering
Volume131
Issue number4
DOIs
StatePublished - Apr 2005

Keywords

  • Abatement and removal
  • Cations
  • Clogging
  • Nitrates

ASJC Scopus subject areas

  • Environmental Engineering
  • Civil and Structural Engineering
  • Environmental Chemistry
  • Environmental Science(all)

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