Synthesis and bromate reduction of sulfate intercalated Fe(II)-Al(III) layered double hydroxides

The objectives of this study were to (i) synthesize layered double hydroxides (LDH) of Fe2+ and Al3+ containing sulfate ion in the interlayer space, and (ii) to evaluate the reduction of bromate in NaBrO3 solution. The LDH was synthesized by co-precipitation method. The LDH was crystalline having a chemical formula [Fe0.672+Al0.333+(OH)(2)][(SO4)(0.16)center dot 1.3H(2)O]. The kinetic study showed that bromate was reduced from 100 mu mol/dm(3) to less than 0.07 mu mol/dm(3) by the LDH in 1 h. The concentration of bromide in the aqueous solution proportionally increased as bromate was reduced by Fe(II) of the LDH. After repeated use of the LDH in NaBrO3 solution for bromate reduction (5th run), the LDH transferred to alpha-FeOOH and amorphous aluminum hydroxide because of oxidation of structural Fe(II) of the LDH. (C) 2011 Elsevier B.V. All rights reserved.