Hydrothermal synthesis, characterization and sorption properties of Al/Fe oxide-oxyhydroxide composite powders

The Al/Fe oxide-oxyhydroxide composite powders were synthesized by hydrothermal method using metal salt solutions and urea as precursors. The effect of the [Al3+]:[Fe3+] ratio and CTAB on the phase composition, textural properties, morphology, and thermal effects of composites was investigated. The b-FeOOH/c-AlOOH powders prepared by hydrothermal treatment of the solutions with [Al3+]:[Fe3+] = 6: 1 showed highest surface area among the as-prepared samples. The morphology of the products was preserved after calcination at 700 degrees C, while the specific surface area significantly increased. The adsorption characteristics of Cr(VI) on the Al/Fe oxide-oxyhydroxide composite powders were investigated. It was shown that the adsorption equilibrium was attained within a short contact time (5-20 min). Adsorption isotherms of all samples were described by the Langmuir and Freundlich equations. Samples calcined at 700 degrees C showed higher adsorption capacity as compared to uncalcined samples. The alpha-Fe2O3/gamma-Al2O3 composite powder has a greater sorption capacity as compared to these of pure gamma-Al2O3 and alpha-Fe2O3. (C) 2016 The Society of Powder Technology Japan. Published by Elsevier B.V. and The Society of Powder Technology Japan. All rights reserved.