Inorganic-organic hybrids originating from organosilane anchored onto leached vermiculite

Abstract

The reactivity of clay minerals leached in grafting reactions was investigated. Precursor solids were prepared by treating the sodium vermiculites with nitric acid solutions at several concentrations. The lixiviation produced the restructured porous solids with surface area over a wide range, varying from 133 to 673 m² g- 1. The sodium and lixiviated vermiculites reacted covalently with silylating agent, 3-aminopropyltrimethoxysilane, to attach this agent onto the inorganic surface, through the free available silanols. The products were characterized by CNH elemental analysis, infrared spectroscopy, X-ray diffraction, nuclear magnetic resonance in the solid state for carbon and silicon. CHN data expressed by significant contents of anchored organic chains, up to 2.14 mmol g- 1, as the degree of leaching was increased. The success of this investigation is directly related to the leaching of the natural vermiculite, which is strongly influenced by the reactivity of the abundant original source.

Keywords

• vermiculite
• organoclays
• selective leaching
• silylation