Activated carbon/iron oxide magnetic composites for the adsorption of contaminants in water

Abstract

In this work the adsorption features of activated carbon and the magnetic properties of iron oxides were combined in a composite to produce magnetic adsorbents. These magnetic particles can be used as adsorbent for a wide range of contaminants in water and can subsequently be removed from the medium by a simple magnetic procedure. Activated carbon/iron oxide magnetic composites were prepared with weight ratios of 2:1, 1.5:1 and 1:1 and characterized by powder XRD, TG, magnetization measurements, chemical analyses, TPR, N 2 adsorption–desorption isotherms, Mössbauer spectroscopy and SEM. The results suggest that the main magnetic phase present is maghemite (γ-Fe 2O 3) with small amounts of magnetite (Fe 3O 4). Magnetization enhancement can be produced by treatment with H 2 at 600 °C to reduce maghemite to magnetite. N 2 adsorption measurements showed that the presence of iron oxides did not significantly affect the surface area or the pore structure of the activated carbon. The adsorption isotherms of volatile organic compounds such as chloroform, phenol, chlorobenzene and drimaren red dye from aqueous solution onto the composites also showed that the presence of iron oxide did not affect the adsorption capacity of the activated carbon.