ENHANCEMENT OF NITRATE REDUCTION IN FEM0-PACKED COLUMNS BY SELECTED CATIONS

Authors: Huang, Yong H.; Zhang, Tian C.

Source: Proceedings of the Water Environment Federation, WEFTEC 2003: Session 21 through Session 30 , pp. 45-53(9)

Publisher: Water Environment Federation

Buy & download fulltext article:

OR

Price: $17.50 plus tax (Refund Policy)

Abstract:

Although permeable reactive barriers (PRBs) using zero-valent iron (ZVI) as reactive media are receiving increasing attention in recent years, the application of ZVI barriers, despite early promise, has not been used as extensively as expected due to the clogging of the reactive media and the passivation of ZVI from the formation of a passive oxide coating. In this paper, we describe the effects of adding some selected cations (e.g., Fe2+, Fe3+, Al3+, and Cu2+) on nitrate removal in Fe0-packed column reactors with the focus on understanding the problems of media clogging and Fe0 passivation. It was found that, due to a rapid passivation of Fe0, only very poor nitrate removal could be achieved in Fe0-packed columns without adding catalytic cations. Long-term performance of the fixed-bed ZVI columns could be remarkably enhanced by adding selected cations, e.g., Fe2+, Fe3+, and AlFe3+; adding Fe3+ achieved the best performance among the four selected cations. In this study, magnetite (Fe3O4) was found to be the major iron corrosion product by nitrate reduction under anoxic conditions; cementation mainly occurred in the inlet zone and was the major cause of the hydraulic clogging. Based on X-ray diffraction analyses, the cementation was likely caused by the formation of lepidocrocite and goethite. The formation of magnetite coating would not necessarily cause clogging of the media. These findings indicate that adding some selected cations into ZVI PRBs might be a method to overcome the passivation problem of iron fillings by its corrosion products.

Document Type: Research Article

DOI: http://dx.doi.org/10.2175/193864703784679161

Publication date: January 1, 2003

More about this publication?
  • Proceedings of the Water Environment Federation is an archive of papers published in the proceedings of the annual Water Environment Federation® Technical Exhibition and Conference (WEFTEC® ) and specialty conferences held since the year 2000. These proceedings are not peer reviewed.

    WEF Members: Sign in (right panel) with your IngentaConnect user name and password to receive complimentary access.
  • Subscribe to this Title
  • Membership Information
  • About WEF Proceedings
  • WEFTEC Conference Information
  • ingentaconnect is not responsible for the content or availability of external websites

Tools

Key

Free Content
Free content
New Content
New content
Open Access Content
Open access content
Subscribed Content
Subscribed content
Free Trial Content
Free trial content

Text size:

A | A | A | A
Share this item with others: These icons link to social bookmarking sites where readers can share and discover new web pages. print icon Print this page