Bromate Ion-Exchange Properties of Crystalline Akaganéite

Abstract

We synthesized crystalline akaganéite (β-FeOOH; Cl− type) by hydrolysis of FeCl3 solution at 100 °C and examined the ion-exchange properties with BrO3−. The uptake rate of BrO3− was so fast that equilibrium was attained in 60 min. The uptake was significantly dependent on pH, showing a maximum uptake at pH ≈ 4. From distribution coefficients (Kd) determined with a mixed solution (BrO3−, Cl−, CO32−, and SO42−; each concentration = 0.1 mmol/dm3), crystalline akaganéite showed the highest selectivity toward BrO3−. The BrO3− uptake was fitted well with the Langmuir model.