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

Taylor, Robert W.

Alabama A and M University, Normal, AL (United States)

关键词: Humic Acids;    Desorption;    Heavy Metals;    Methylmercury;    Sodium;   

DOI  :  10.2172/775037
RP-ID  :  DOE/ER/14718
RP-ID  :  FG07-96ER14718
RP-ID  :  775037

美国|英语

来源: UNT Digital Library

【 摘 要 】

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 .