Adsorption du cadmium dans les sols calcaires du Sud-Est de l'Espagne
(1991) Agronomie — Vol. 11, n° 1, p. 35-44 (1991)
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- Abstract
- Top-soil horizons of a series of 12 calcareous soils in South-Eastern Spain (table I) have been compared for their cadmium adsorption capacity. Data closely obey the Freundlich equation and indicate 2 distinct mechanisms of adsorption (fig 1, table II) according to whether the cadmium in the bulk solution is present in tracer or in higher amounts. In addition, some precipitation with a concomitant decrease in pH could also occur at initial concentrations of Cd higher than 5 mg/l (fig 2). Statistical analysis (tables III and IV) points out that the adsorbed amounts of Cd may be estimated from the CEC (AcNH4) values and the active calcium carbonate content. The agreement between the predictive values and the experimental ones is shown to be fairly good (fig 3). The higher adsorption of Cd in comparison with the noncalcareous soils is due to the reactivity of calcite surfaces (chemisorption and nucleation-precipitation, respectively at low and high rates of Cd) and also to the commonly high pH of the soils studied (7.6 < pH < 8.6). Comparison of the adsorption isotherms measured in chloride (CaCl2 0,01 mol.l-1) and perchlorate (Ca(ClO4)2 0,01 mol.l-1) media (fig 4) points out that adsorption of Cd is mainly determined by the activity of free Cd2+ in the soil solution.
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Halen, H., Garcianavarro, M., & Van Bladel, R. (1991). Adsorption du cadmium dans les sols calcaires du Sud-Est de l’Espagne. Agronomie, 11(1), 35-44. https://doi.org/10.1051/agro:19910105 (Original work published 1991)