Removal of metals by activated carbon-cobalt ferrite magnetic composites

Abstract

Composite of activated carbon and cobalt ferrite (AC-CoFe₂O₄) was synthesized by co-precipitation method for removal of metal ions in water. The prepared adsorbent morphology and chemical bond information was characterized by XRD, FT-IR, surface area analysis and scanning electron microscope. The dispersion of the composite in water was better than non-composite cobalt ferrite. The adsorption studies were performed using batch method and the efficiency in Pb(II), Ni(II) and Zn(II) ions removal were evaluated under influence of certain parameters. The composite AC-CoFe₂O₄ showed higher efficiency in removal of all metal ions, compared to non-composite materials. The suitable contact time was 1 hour for removal of Pb(II) and Ni(II) and 2 hour for Zn(II). The suitable pH value for adsorption was 6 and the leaching of cobalt and iron from the composite was observed during adsorption at pH 1-3. The adsorption kinetics followed the pseudo-second order. The adsorption behavior of all metal ions on the composite could be described by Langmuir isotherm assumptions. The maximum capacity of AC-CoFe₂O₄ in the adsorption of Pb(II), Ni(II) and Zn(II) were 90.91, 8.06 and 14.49 mg g⁻¹. The presence of salts including sodium nitrate, sodium sulfate and calcium nitrate at 0.1 M and 1.0 M reduced the efficiency in removal of all metal ions by the adsorbent.