Identification of superactive centers in thermally treated formamide-intercalated kaolinite

Frost, Ray L., Horvath, Erzsebet, Kristof, Janos, Jakab, Emma, Mako, Eva, & Vagvolgyi, Veronika (2005) Identification of superactive centers in thermally treated formamide-intercalated kaolinite. Journal of Colloid and Interface Science, 289(1), pp. 132-138.

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Abstract

The thermal behavior of a formamide-intercalated mechanochemically activated (dry-ground) kaolinite was investigated by thermogravimetry-mass spectrometry (TG-MS) and diffuse reflectance Fourier transform infrared spectroscopy (DRIFT). After the removal of adsorbed and intercalated formamide, a third type of bonded reagent was identified in the 230 - 350 degrees Celsius temperature range decomposing in situ to CO and NH3. The presence of formamide decomposition products as well as CO2 and various carbonates identified by DRIFT spectroscopy indicates the formation of super-active centers as a result of mechanochemical activation and heat treatment (thermal deintercalation). The structural variance of surface species decreases with the increase of grinding time. The ungrounded mineral contains a low amount of weakly acidic and basic centers. After 3 hours of grinding, the number of acidic centers increases significantly, while on further grinding the super-active centers show increased basicity. With the increase of grinding time and treatment temperature the amount of bicarbonate- and bidentate-type structures decreases in favor of the carboxylate- and monodentate.

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30 citations in Scopus
30 citations in Web of Science®
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ID Code: 1827
Item Type: Journal Article
Refereed: Yes
Keywords: nanochemistry, nanotechnology, Kaolinite, intercalation, mechanochemical activation, thermogravimetry, mass spectrometry (TG, MS), diffuse reflectance Fourier transform infrared spectroscopy (DRIFT)
DOI: 10.1016/j.jcis.2005.03.059
ISSN: 0021-9797
Divisions: Past > QUT Faculties & Divisions > Faculty of Science and Technology
Copyright Owner: Copyright 2005 Elsevier
Copyright Statement: Reproduced in accordance with the copyright policy of the publisher.
Deposited On: 13 Jul 2005 00:00
Last Modified: 29 Feb 2012 13:17

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