Kinetics and Mechanism of Metal Retention/Release in Geochemical Processes in Soil - Final Report

Technical Report · Fri Dec 29 04:00:00 EST 2000

DOI:https://doi.org/10.2172/775037· OSTI ID:775037

Taylor, Robert W ^[1]

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1. Alabama A&M University

Effective, remediation of soils contaminated with heavy metals requires a better understanding of the mechanisms by which the metals are retained/released in soils over a long period of time. Studies on reaction of Cr(VI) with iron-rich clays indicated that structural iron (II) in these surfaces is capable of reducing chromate to chromium (III). We found that iron (II) either found naturally or produced by treatment of clay with sodium dithionite, effectively reduced Cr (VI) to Cr (III). Thus, in situ remediation of chromium combines reduction of Cr (VI) to Cr (III) and immobilization of chromium on mineral surfaces. During this study, lead sorption on a kaolin surface was found to be a rapid and a pH dependant process in which lead sorption significantly increased with the amount of phosphate on the clay surface. This study verifies that methylmercury cation remains intact when it binds to humic acids, forming a monodentate complex with some sub-population of humic thiol ligands .

• Research Organization: Alabama A and M University, Normal, AL (US)
• Sponsoring Organization: USDOE Office of Environmental Management (EM) (US)
• DOE Contract Number: FG07-96ER14718
• OSTI ID: 775037
• Report Number(s): DOE/ER/14718; Project Number 55014
• Country of Publication: United States
• Language: English

Related Subjects

54 ENVIRONMENTAL SCIENCES
58 GEOSCIENCES
CATIONS
CHROMATES
CHROMIUM
CHROMIUM (VI)
CLAYS
DESORPTION
HEAVY METALS
HUMIC ACIDS
IRON
KAOLIN
KINETICS
LEAD
METHYLMERCURY
PHOSPHATES
SODIUM
SOILS
SORPTION
THIOLS