Adsorption of heavy metals in glacial till soil |
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Authors: | Ashraf Z Al-Hamdan Krishna R Reddy |
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Institution: | (1) Department of Civil and Environmental Engineering, University of Central Florida, 162450, Orlando, Florida 32816-2450, USA;(2) Department of Civil and Materials Engineering, University of Illinois at Chicago, 842 West Taylor Street, Chicago, Illinois 60607, USA |
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Abstract: | The charged sites on soil particles are important for the retention/adsorption of metals. Metallic counterions can neutralize
the intrinsic charges on the surfaces of soil particles by forming complexes. In this study, efforts have been made to determine
the effect of surface potential, pH, and ionic strength on the adsorption of four metal ions, hexavalent chromium Cr(VI),
trivalent chromium Cr(III), nickel Ni(II) and cadmium Cd(II), in glacial till soil. Batch tests were performed to determine
the effect of pH (2–12) and ionic strength (0.001–0.1 M KCl) on zeta potential of the glacial till soil. The point of zero
charge (pH
PZC
) of glacial till was found to be 7.0±2.5. Surface charge experiments revealed the high buffering capacity of the glacial
till. Batch adsorption experiments were conducted at natural pH (8.2) using various concentrations of selected metals. The
adsorption data was described by the Freundlich adsorption model. Overall glacial till shows lower adsorption affinity to
Cr(VI) as compared to cationic metals, Cr(III), Ni(II) and Cd(II). |
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Keywords: | adsorption clays electrokinetics heavy metals remediation soil zeta potential |
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