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Iron Oxide Silica Derived from Sol-Gel Synthesis
FIMLab—Films and Inorganic Membrane Laboratory, School of Chemical Engineering, The University of Queensland, Brisbane Qld 4072, Australia
Institut Europeen des Membranes, Universite Montpellier 2, Place Eugene Bataillon 34095, Montpellier, cedex 5, France
* Author to whom correspondence should be addressed.
Received: 28 December 2010; in revised form: 31 January 2011 / Accepted: 16 February 2011 / Published: 17 February 2011
Abstract: In this work we investigate the effect of iron oxide embedded in silica matrices as a function of Fe/Si molar ratio and sol pH. To achieve homogeneous dispersion of iron oxide particles, iron nitrate nonahydrate was dissolved in hydrogen peroxide and was mixed with tetraethyl orthosilicate and ethanol in a sol-gel synthesis method. Increasing the calcination temperature led to a reduction in surface area, although the average pore radius remained almost constant at about 10 Å, independent of the Fe/Si molar ratio or sol pH. Hence, the densification of the matrix was accompanied by similar reduction in pore volume. However, calcination at 700 °C resulted in samples with similar surface area though the iron oxide content increased from 5% to 50% Fe/Si molar ratio. As metal oxide particles have lower surface area than polymeric silica structures, these results strongly suggest that the iron oxides opposed the silica structure collapse. The effect of sol pH was found to be less significant than the Fe/Si molar ratio in the formation of molecular sieve structures derived from iron oxide silica.
Keywords: iron oxide; silica network; molecular sieve structures
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MDPI and ACS Style
Darmawan, A.; Smart, S.; Julbe, A.; Diniz da Costa, J.C. Iron Oxide Silica Derived from Sol-Gel Synthesis. Materials 2011, 4, 448-456.
Darmawan A, Smart S, Julbe A, Diniz da Costa JC. Iron Oxide Silica Derived from Sol-Gel Synthesis. Materials. 2011; 4(2):448-456.
Darmawan, Adi; Smart, Simon; Julbe, Anne; Diniz da Costa, João Carlos. 2011. "Iron Oxide Silica Derived from Sol-Gel Synthesis." Materials 4, no. 2: 448-456.