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The aim of this study was to evaluate the distribution of zinc among solute, adsorbed and precipitated phases in calcareous and basaltic soils. For this purpose, the results of sorption batch experiment, conducted at pH = 6 ± 0.2, have been investigated using Freundlich and Langmuir equations and combining a thermodynamic approach and X-ray diffraction (XRD) spectroscopy. It has been shown that both Freundlich and Langmuir models fit similarly well the data of zinc uptake, and corroborates the hypothesis that Banias soil expresses more affinity for zinc retention. The exponential evolution of distribution coefficient KD with ZnTOT indicates that higher affinity is expressed at low degrees of coverage. The partitioning among zinc species in solution indicated that the free ions of zinc Zn2+ were the most dominant in solution. The predictions based upon the thermodynamic calculation, and the evidences provided by XRD spectroscopy corroborate and show both the precipitation of zinc as franklinite ZnFe2O4. This mineral hence may deeply affect the dynamic of zinc in natural environment in presence of iron minerals

distribution co-efficien , zinc , basaltic soil , calcareous soil , affinity , precipitation , speciation , sorption

2008

مجله جامعه تشرين: العلوم البيولوجيه

مجله جامعه تشرين: العلوم البيولوجيه