Thermal decomposition of the hydrotalcite Zn6Al2CO3(OH)16.4H2O – a Thermogravimetric analysis and hot stage Raman spectroscopic study

Frost, Ray L. and Martens, Wayde N. and Erickson, Kristy L. (2005) Thermal decomposition of the hydrotalcite Zn6Al2CO3(OH)16.4H2O – a Thermogravimetric analysis and hot stage Raman spectroscopic study. Journal of Thermal Analysis and Calorimetry, 82(3). pp. 603-608.

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DOI: 10.1007/s10973-005-0940-y

Abstract

A combination of thermogravimetry and hot stage Raman spectroscopy has been used to study the thermal decomposition of the synthesised zinc substituted takovite Zn6Al2CO3(OH)16.4H2O. Thermogravimetry reveals seven mass loss steps at 52, 135, 174, 237, 265, 590 and ~780 degrees Celsius. MS shows that the first two mass loss steps are due to dehydration, the next two to dehydroxylation, the mass loss step at 265 degrees Celsius to combined dehydroxylation and decarbonation. The two higher mass loss steps are attributed to decarbonation. Raman spectra of the hydroxyl stretching region over the 25 to 200 degrees Celsius temperature range, enable identification of bands attributed to water stretching vibrations, MOH stretching modes and strongly hydrogen bonded CO32- -water bands. CO32- symmetric stretching modes are observed at 1077 and 1060 cm-1. One possible model is that the band at 1077 cm-1 is ascribed to the CO32- units bonded to one OH unit and the band at 1092 cm-1 is due to the CO32- units bonded to two OH units from the Zn-takovite surface. Thermogravimetric analysis when combined with hot stage Raman spectroscopy forms a very powerful technique for the study of the thermal decomposition of minerals such as hydrotalcites.

ID Code:	3504
Item Type:	Journal Article
Keywords:	stitchtite, iowaite, desautelsite, takovite, hydrotalcite, Raman spectroscopy, thermal analysis, thermogravimetry
ISSN:	1572-8943
Subjects:	Australian and New Zealand Standard Research Classification > CHEMICAL SCIENCE (030000)
Divisions:	QUT Faculties and Divisions > Faculty of Science and Technology
Copyright Owner:	Copyright 2005 Springer
Copyright Statement:	The original publication is available at SpringerLink http://www.springerlink.com
Deposited On:	09 Feb 2006
Last Modified:	23 Jan 2009 02:44

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