Remobilization of heavy metals under the action of edta
Remobilization of heavy metals from a variety of mineral and organic sediments (soil, industrial waste, sewage sludge, etc.) under the action of chelating agents is one of the ways of heavy metal migration in natural waters. Along with experimental studies of the process of remobilization, there is a need for theoretical modeling of equilibria in the metal cation-chelating-adsorbent. In this work chelating agents and considered complexone remobiling effect of EDTA on the doubly charged heavy metal cations adsorbed on the surface of ferrihydrite has been overviewed. Remobilization was shown to occur at pH 5-8, with maximum efficiency in soft water at pH 8.0. In more acidic solutions EDTA dissolves ferrihydrite by formation Fe (III) complexones. By the ability to partition under the action of EDTA, cations are arranged in series: Ni (II)> Co (II)> Cd (II)> Cu (II)> Zn (II)> Mn (II)> Pb (II). A Ca (II) and Mg (II) cation increase leads to a decrease in remobilization, with an increase in alkalinity of the medium effect of water hardness on the remobilization. The results compared with experimental data have been presented.