Iron Oxide-Coated Gravel Fixed Bed Column Study Performance to Remove Mixed Metals from Landfill Leachate

Iron oxide-coated gravel as an adsorbent was employed in continuous fixed bed column study to remove Fe(II), Ni(II), and Zn(II) simultaneously in synthetic leachate samples. Experimental and modeled adsorption capacities derived from the breakthrough curves showed the adsorption capacity order of Zn(II)>Fe(II)> Ni(II). Iron oxide-coated gravel column removed 58.24% of Zn(II), 47.71% of Fe(II), and 39.45% of Ni(II). Desorption process was studied in order to test the regeneration capability of iron oxidecoated gravel. It was seen that 99.64 % of Ni(II), 99.54% of Fe(II) and 6.75% of Zn (II) were recovered through the first cycle of adsorption/desorption. In the second cycle, the recovery rates dropped to 81.4% for Ni(II), 80% for Fe(II) and 4% for Zn(II). Based on these results, iron oxide coated gravel has potential to remove mixed metal ions simultaneously in aqueous solutions.