Organosilica mesoporous materials with double functionality: Amino groups and β-cyclodextrin synthesis and properties

Abstract

Our work concerns the preparation of new organofunctional mesoporous silica gels. The goal of this study is to combine in a unique material -on one hand β-cyclodextrin (β-CD), able to form stable inclusion complexes with many organic molecules, - and on the other hand aminogroups (from aminopropylsilane precursor) which are likely to chelate metallic cations. At the same time the formation of a mesoporous silica network would improve and regulate the access to functional sites. In order to tailor the functionalities content of our materials, a preparation in two steps has been chosen. First, a new silica precursor (β-CDAPS) has been synthesized from a β-CD derivative and (3-aminopropyl) trimethoxysilane (APS). A detailed characterization of the obtained product has helped to determine the structure of β-CDAPS repeating unit and quantify its functionality. Then this hybrid precursor has been co-condensed with tetraethylorthosilicate (TEOS) via a sol-gel process involving the use of surfactants by a S-I+ mechanism. Porous and chemical structures of a series of these functional mesoporous silicas were characterized. Finally, preliminary adsorption tests of aqueous model pollutants, carried out on these hybrid materials, have been discussed. © 2008 Springer Science+Business Media B.V.