Preparation of Magnetic Fe-Al Binary Oxide and Its Application in Superconducting Magnetic Separation

Iron oxide is widely used for the adsorption of oxyanion and anionic pollutants in water. Incorporation of aluminum expands available Fe oxide surface that can contact with pollutants because amorphous Al oxide exhibits extremely large surface area with porous morphology. Magnetic Fe-Al binary oxide was prepared by adjusting temperature during sintering of the oxides and investigated the feasibility of the magnetic adsorbent for chromate removal from aqueous solution with permanent and superconducting magnets. The Fe-Al oxide was highly magnetized (31.4 emu/g) after sintering at 500 °C. It is considered that the highly magnetized Fe-Al oxide with comparably large surface area can be a good magnetic adsorbent. The initial chromate solution with the adsorbent had 110 NTU of turbidity. After the superconducting magnetic separation with 0.5, 1, and 4 T, the turbidity of the solution decreased to 31.8, 12.3, and 7.7 NTU, respectively. The Fe-Al oxide is an effective magnetic adsorbent that can not only adsorb anionic pollutants, but also be separated by superconducting magnetic separation system.