Fe-Al layered double hydroxides in bromate reduction: Synthesis and reactivity

This study presents a rare use of layered double hydroxides of Fe(II) and Al(III) (Fe-Al LDH), as reported for the first time for bromate removal from aqueous solutions. The Fe-Al LDH samples were prepared with Fe/Al molar ratios of 1-4 using a co-precipitation method at pH 7, with subsequent hydrothermal treatment at 120 degrees C. The Fe-Al LDH (molar ratio of Fe/Al = 1, 2) with a layered structure exhibited nearly complete removal of bromate from initial concentration of 100 mu mol/dm(3) at a wide pH range of 4.0-10.5 over a 2 h reaction period; the residual bromate concentration in the solution was lower than the detection limit of 0.07 mu mol/dm(3) (9 mu g-BrO3-/dm(3)). During the reaction period, bromide was released into the solution via a reduction process. Reactivity of Fe-Al LDH with a Fe/Al molar ratio of 2 did not decrease the bromate reduction efficiency during 30 days. (C) 2010 Elsevier Inc. All rights reserved.