Adsorption-desorption behaviors of Cu, Zn, Mn and Fe in calcareous soils.

摘要

The adsorption-desorption behaviour of Cu2+, Zn2+, Mn2+ and Fe2+ was studied on the Egyptian calcareous soil surface at two pH 5.5 and 7.5. The initial concentration used for each metal was 25 ppm. The experiment was performed using the four elements individually and in a mixture of two elements Cu+Zn, Cu+Mn, Cu+Fe, Zn+Mn, Zn+Fe and Mn+Fe. In addition, a mixture of the four elements Cu+Zn+Mn+Fe was studied; with 25 ppm initial concentration for each element either for individual elements or mixtures at two pH 5.5 and 7.5. The Na2EDTA salt was used to study the desorption behaviour. The adsorption of heavy metals followed the magnitude Zn > Fe> Mn > Cu, while the magnitude of desorption was Cu > Zn > Fe > Mn at pH 5.5 and 7.5. While the magnitude of selectivity was in the order Fe > Mn > Zn > Cu at both pH..