New range of Al-Mg organoclays with tailored hydrophobicity:: incorporation of fluoride as a local probe to study the octahedral character

A series of inorganic-organic hybrids with a phyllosilicate-like structure were prepared using a single-step templating sol-gel procedure. The synthesis involves reaction of magnesium nitrate and aluminum acetylacetonate with octyltriethoxysilane, to give products where saponite is the inorganic parent. These hybrids were characterized by X-ray diffraction, solid-state Si-29, C-13 and Al-27 nuclear magnetic resonance, infrared spectroscopy and thermogravimetry. The results showed that the hybrid materials exhibit lamellar structures, similar to those found in natural inorganic silicate saponite. The influence of the substitution of magnesium and silicon by aluminum was evident from Si-29 and C-13 NMR studies. A high degree of condensation was obtained. The hydrophobic character was evaluated by wettability measurements. These materials hold promise as sorbents for solid-phase extraction of organic pollutant molecules, due to their highly hydrophobic character. (C) 2003 Elsevier Inc. All rights reserved.