COPPER(II) ION IMMOBILIZATION BY HUMIC ACID CONVERTED INTO POORLY SOLUBLE FORM
Humic acid (HA) isolated from peat has been applied for immobilization of Cu2+ ions to remediate polluted soil. HA solubility has been decreased at рН ≥ 5 by its treatment with Fe3+ ions (0.1 mmol/g HA). Sorption equilibriums in HA-Cu2+-Н2О system have been investigated at рН 3.5, 4.0 and 5.0 at 250С. The results have been analyzed using isotherm equations of Henry, Langmuir and Freundlich. To specify the sorption mechanism, the IK-spectra of HA and sorption products have been registered. It has been shown, that HA sorption capacity and the bond of Cu2+ with -СОО- ions increase, the molar coefficient of Н+/Cu2+ exchange decreases with the increase of рН.