The Application of Chelating Agents for Remediation of Soils, Polluted by Heavy Metals

Abstract

There was displayed a possibility of chelating agents  application (EDTA, EDTMP) for remediation of sod-podzol soils, which were artificially polluted with by heavy metals (HM) – Cu(II), Pb(II), Zn(II), Cd(II). There was established a dependence of HM sorption on some factors (nature of metals, pH, and humic matter content in soils). There was described identical sorption behavior of low humic soils and synthetic goethite (α-FeOOH). There was studied process of soils demutualization by the action of water solutions of chelating agents under different value of pH of extract solution (pH = 2 - 10) and mole ratio reagents (chelating agent : HM = 1 - 20). There was demonstrated that the extraction by EDTA solution (twentyfold redundancy in relation to HM) during 1 - 2 hours leads to high degree of extraction of Cu (II), Cd (II) (70 – 95 % of acid-soluble forms) and less effective extraction of Pb (II) (5 – 35 %). Optimal for extraction pH of medium corresponds to range of pH of 5 - 8. Desorbed action of EDTMP was expressed more weak (in comparison with EDTA), that is connected with more strong sorption of phosphonates.