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Résumé :
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Batch experiments were performed to examine the BrO3− uptake from dilute aqueous solutions on amorphous aluminum hydroxide (Cl− type), which was synthesized by addition of a 3 mol/dm3 NaOH solution to a 0.1 mol/dm3 AlCl3 solution until the pH reached 5.8. The uptake from a 0.78 μmol/dm3 BrO3− solution (100 μg of BrO3/dm3) was rapid: equilibrium was attained within 3 min. The BrO3− uptake was found to decrease slowly at pH 4−8 and rapidly at pH >8. The isotherm for BrO3− uptake was well fitted with the Freundlich isotherm model. From distribution coefficient (Kd) values determined from mixed solutions containing 0.10, 1.0, and 2.0 mmol/dm3 NaCl, NaBrO3, NaNO3, Na2SO4, and Na2CO3, the selectivity order was reported as NO3− < BrO3− < SO42− at a pH range 4.8−7.9. These results suggest that the BrO3− uptake on the amorphous aluminum hydroxide occurs through an outer-sphere complex reaction.
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