Adsorption properties of nanostructured form of aluminium hydroxide γ-modification

Adsorption properties of aluminium hydroxide.-modification towards toxic copper(II) and zinc(II) ions were studied. In a neutral medium at pH=7.6, the ion adsorption capacity was 264 mg/g for copper(II) and 338 mg/g for zinc(II). The study of the temperature effect on the absorbability of toxic ions established that the adsorption capacity is characterized by an increase followed by a decrease as the equilibrium value is reached. The absorbability increase in the initial moment is caused by an increase in the formation rate of hydroxo aqua complexes of copper(II) and zinc(II) ions. The differential heat of adsorption was determined. It demonstrated a decrease from 27 to 20 kJ/mol during the process, which is caused by the fact that, as the most active centres of nanostructured form of aluminium hydroxide.-modification are saturated, heavy metal ions are adsorbed by decreasingly active regions of its surface.