Removal of contaminants from aqueous solution by reaction with iron surfaces
Irrigation drainage and industrial wastewaters often contain elevated levels of toxic oxyanions and oxycations such as selenate, chromate, and uranyl. A potential remediation method is to react contaminated water with zero-valent iron, which transforms the mobile contaminants into immobile forms. In this work, iron foil was exposed to aqueous solutions containing the relevant ions, and the reacted surfaces were characterized by scanning tunneling microscopy (STM) and X-ray photoelectron spectroscopy (XPS). STM images collected in situ show that the protrusions on the foil surface associated with iron oxides are smoothed out by the reaction. XPS indicates that partially reduced Se(IV) and Cr(III) are adsorbed on the surface, while uranium is deposited as U(VI), i.e., without reduction. More Se and Cr are deposited when the atmospheric gases are removed from solution because of the elimination of a competing process in which dissolved O{sub 2} increases the thickness of the iron oxide overlayer to the point where the reduction reaction is quenched. The amount of U deposited is greatly increased when the atmospheric gases are removed because of the elimination of dissolved CO{sub 2}, which can form carbonate complexes with uranium.
- Research Organization:
- Univ. of California, Riverside, CA (US)
- Sponsoring Organization:
- USDOE; National Science Foundation (NSF); US Department of the Army; US Department of the Navy; US Department of the Air Force
- DOE Contract Number:
- FG07-96ER14707
- OSTI ID:
- 20017510
- Journal Information:
- Langmuir, Vol. 16, Issue 5; Other Information: PBD: 7 Mar 2000; ISSN 0743-7463
- Country of Publication:
- United States
- Language:
- English
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