Inorganic contaminant diffusion and reaction within Fe oxides: Evaluation of the rate limiting process for leaching in subsurface environments

Conference · Fri Dec 01 04:00:00 EST 1995

OSTI ID:126437

Axe, L ^[1]; Anderson, P ^[2]

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1. Argonne National Lab., IL (United States)
2. Pritzker Dept. of Environmental Engineering, Chicago, IL (United States)

Although many models used to describe leaching processes am based on the assumption of a rapid equilibrium between the bulk aqueous and solid phases, they generally have not been successful at simulating contaminant distribution in subsurface environments. This lack of success stems from the failure to consider kinetic aspects of contaminant partitioning. Researchers have found that oxides of manganese and especially iron often control contaminant sorption. In the two-step sorption of inorganics by oxide minerals, the first step is a fast, reversible reaction between the bulk aqueous phase and the sorbent external surface sites. The second step is a slow process wherein the contaminant at the surface slowly diffuses into the interior of the oxide particle. During intraparticle transport, the contaminant diffuses through micropores along interior surface sites. This configurational surface diffusion is the rate controlling mechanism in the sorption process.

• OSTI ID: 126437
• Report Number(s): CONF-950402--
• Country of Publication: United States
• Language: English

Related Subjects

40 CHEMISTRY
54 ENVIRONMENTAL SCIENCES
ADSORPTION
ADSORPTION ISOTHERMS
CADMIUM
DIFFUSION
ENVIRONMENTAL TRANSPORT
EQUILIBRIUM
GROUND WATER
IRON OXIDES
LEACHING
OXIDE MINERALS
RADIONUCLIDE MIGRATION
SOILS
SORPTIVE PROPERTIES
STRONTIUM