Adsorptive Removal of Copper (II) Ions from Aqueous Solution using Acid and Thermally Activated Iron Oxide Sand

Abstract

Heavy metal pollution of water bodies is a common problem in Zambia, whose economy depends on copper mining. Removal of Cu2+ ions from the solution via adsorption using iron oxide ore was investigated. The composition of the adsorbent was determined by XRF and ICP-OES. Iron oxide had predominantly Fe2O3 at 60 % with less than 3% of SiO2 and Al2O3. The Cu2+ ion concentrations were measured before and after adsorption using Atomic Absorption Spectroscopy (AAS). The effects of initial concentration, pH, acid activation, and thermal activation of the adsorbent on adsorption were investigated. A decrease in the adsorption of Cu2+ ions with an increase in the initial concentration of adsorbate (Cu2+) was observed. The adsorption of Cu2+ ions on acid-activated Iron oxide compared to thermally activated iron oxide ranged from 83-73%, respectively. Adsorption of Cu2+ ions was pH dependent with an optimum pH of 7. Acid activation of the adsorbent had better absorptivity since acids cause mineral dissolution, which increases the surface area and porosity of the adsorbent. Iron Oxide adsorbents have the potential to the removal of Cu2+ ions from aqueous solutions. Keywords: Adsorption, Copper ions, Heavy metals, Iron oxide, Pollution.