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Interactions between cadmium and lead with acidic soils: Experimental evidence of similar adsorption patterns for a wide range of metal concentrations and the implications of metal migration

Pokrovsky, Oleg S. and Probst, Anne and Leviel, E. and Liao, Bo-han Interactions between cadmium and lead with acidic soils: Experimental evidence of similar adsorption patterns for a wide range of metal concentrations and the implications of metal migration. (2012) Journal of Hazardous Materials, vol. 199-200 . pp. 358-366. ISSN 0304-3894

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Official URL: http://dx.doi.org/10.1016/j.jhazmat.2011.11.027

Abstract

The importance of high- and low-affinity surface sites for cadmium and lead adsorption in typical European and Asian soils was investigated. Adsorption experiments on surface and deep horizons of acidic brown (Vosges, France) and red loess soils (Hunan, China) were performed at 25 ◦C as a function of the pH (3.5–8) and a large range of metal concentrations in solution (10−9–10−4 mol l−1). We studied the adsorption kinetics using a Cd2+-selective electrode and desorption experiments as a function of the solid/solution ratio and pH. At a constant solution pH, all samples exhibited similar maximal adsorption capacities (4.0 ± 0.5 µmol/g Cd and 20 ± 2 µmol/g Pb). A constant slope of adsorbed–dissolved concentration dependence was valid over 5 orders of magnitude of metal concentrations. Universal Langmuir and Freundlich equations and the SCM formalism described the adsorption isotherms and the pH-dependent adsorption edge over very broad ranges of metal concentrations, indicating no high- or low-affinity sites for metal binding at the soil surface under these experimental conditions. At pH 5, Cd and Pb did not compete, in accordance with the SCM. The metal adsorption ability exceeded the value for soil protection by two orders of magnitude, but only critical load guarantees soil protection since metal toxicity depends on metal availability.

Item Type:Article
Additional Information:Thanks to Elsevier editor. The definitive version is available at http://www.sciencedirect.com/science/article/pii/S0304389411013938
Audience (journal):International peer-reviewed journal
Uncontrolled Keywords:
Institution:French research institutions > Centre National de la Recherche Scientifique - CNRS
Université de Toulouse > Institut National Polytechnique de Toulouse - INPT
French research institutions > Institut de Recherche pour le Développement - IRD
Université de Toulouse > Université Paul Sabatier-Toulouse III - UPS
Other partners > Central South University of Forestry and Technology - CSUFT (CHINA)
Laboratory name:
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Deposited By: Nadia Kelmouss

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