Thermally induced release of adsorbed Pb upon aging ferrihydrite and soil oxides
- Cornell Univ., Ithaca, NY (United States). Dept. of Soil, Crop, and Atmospheric Sciences
In this study, thermally induced transformation products and the solubility of preadsorbed Pb were compared in a synthetic ferrihydrite and two natural materials containing iron oxides. The adsorbents were characterized initially and after heating for 60 days at 70 C. Dissolved Pb was measured by differential pulse anodic stripping voltammetry (dpasv) in the supernatants after heating the suspensions for 60 days at 70 C and compared to the solubility after adsorption for 15 days at room temperature. Lead activities were calculated from dpasv measurements. Surface area, FTIR, XRD analyses, and extraction with oxalate and pyrophosphate were used to characterize the solid phases. Iron oxide transformation products differed among the systems. The laboratory-synthesized ferrihydrite showed the most distinct transformation to goethite and hematite. Goethite formation was also evidenced from one natural (SMS-1) material. The other (SMS-2) material, with a low surface area initially and no FTIR or XRD evidence of crystalline or noncrystalline iron oxide, revealed limited transformation after thermal treatment. Despite these differences, Pb activity increased from all adsorbents after heating for 60 days at 70 C. The amount of adsorbed Pb had no effect on iron oxide transformation products. Differences in the degree of transformation and in the identity of transformation products may be due to the presence of organic matter, Si, and Al in the pedogenic materials as well as to the initial Fe forms present in the samples.
- OSTI ID:
- 6482837
- Journal Information:
- Environmental Science and Technology, Journal Name: Environmental Science and Technology Vol. 33:12; ISSN ESTHAG; ISSN 0013-936X
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
540220* -- Environment
Terrestrial-- Chemicals Monitoring & Transport-- (1990-)
ADSORPTION
BIOLOGICAL AVAILABILITY
CHALCOGENIDES
CHEMISTRY
ELEMENTS
IRON COMPOUNDS
IRON OXIDES
LAND POLLUTION
LEAD
METALS
OXIDES
OXYGEN COMPOUNDS
POLLUTION
SOIL CHEMISTRY
SOILS
SORPTION
TRANSITION ELEMENT COMPOUNDS