The synthesis and spectroscopic characterisation of hydrotalcite formed from aluminate solutions.

Sara J Palmer, Laure M Grand, Ray L Frost

Inorganic Materials Research Program, School of Physical and Chemical Sciences, Queensland University of Technology, Queensland, Australia.

Spectrochimica acta. Part A, Molecular and biomolecular spectroscopy 2011 Jun

filter terms:

Raman spectroscopy has been used to characterise nine hydrotalcites prepared from aluminate and magnesium solutions (magnesium chloride and seawater). The aluminate hydrotalcites are proposed to have the following formula Mg(6)Al(2)(OH)(16)(CO(3)(2-))·xH(2)O, Mg(6)Al(2)(OH)(16)(CO(3)(2-),SO(4)(2-))·xH(2)O, and Mg(6)Al(2)(OH)(16)(SO(4)(2-))·xH(2)O. The synthesis of these hydrotalcites using seawater results in the intercalation of sulfate anions into the hydrotalcite interlayer. The spectra have been used to assess the molecular assembly of the cations and anions in the hydrotalcite structures. The spectra have been conveniently subdivided into spectral features based upon the carbonate anion, the hydroxyl units and water units. This investigation has shown the ideal conditions to form hydrotalcite from aluminate solutions is at pH 14 using a magnesium chloride solution at a volumetric ratio of 1:1. Changes in synthesis conditions resulted in the formation of impurity products aragonite, thenardite, and gypsum. Copyright © 2011 Elsevier B.V. All rights reserved.

Citation

Sara J Palmer, Laure M Grand, Ray L Frost. The synthesis and spectroscopic characterisation of hydrotalcite formed from aluminate solutions. Spectrochimica acta. Part A, Molecular and biomolecular spectroscopy. 2011 Jun;79(1):156-60