Microwave power effect on hydrotalcite synthesis

Abstract

Hydrotalcite-like compounds, also referred as double layered hydroxides, are anionic clay-like compounds. They are microporous minerals with a layered structure. As they are scarcely found in nature they are usually synthesized through co-precipitation methods. A remarkable improvement in time and solution concentrations has been attained by microwaving the synthesis solutions. The obtained materials are original and different from those provided by the co-precipitation method. In this work, we correlate the features of the obtained hydrotalcite-like compounds, Mg/Al and Zn,Mg/Al, with the microwave intensity, the anion and cation nature, among others. When magnesium is incorporated at 200 W it remains in the outer layers of the hydrotalcite inhibiting the Zn diffusion which, then, forms zinc oxide. The irradiation power determines the homogeneity of the obtained materials as at 600 W the obtained hydrotalcite is more homogeneous than the one synthesized at 200 W. (c) 2005 Elsevier Inc. All rights reserved.