Hybrid composites prepared by carbonization of acetylacetone and metal acetylacetonates on a surface of silica gel

Abstract

Hybrid adsorbents with carbon/silica, carbon/metal oxide/silica, and carbon/metal/silica could be of interest from a practical point of view since they can effectively adsorb both polar and nonpolar compounds. Therefore, mesoporous silica gel Si–60 modified by carbonization acetylacetone or Ti, Zn, Ni, Co, Cr, Zr acetylacetonates has been studied using nitrogen and water adsorption–desorption, thermogravimetry, transmission electron microscopy, X–ray diffraction, and X–ray fluorescence methods. Grafted C/X phases consist of metal compounds (X denotes metal oxide or silicate or/and metal) and char, whose characteristics can be varied changing metal in the precursors and their amounts. The morphological, structural, and textural characteristics of C/X/SiO2, such as composition and particle size distributions of deposits, a number and kind of polar and non polar surface sites, specific surface area, pore volume, and pore size distributions depend on the type, content, and distribution of the C/X deposits. The changes in the grafted matters occur with increasing precursor and C/X concentrations and a possible catalytic effect of the X phases on the carbonization reactions. Appropriate selection of precursor structure and amounts allows one to vary and control the characteristics of whole hybrid adsorbents that is of importance from a practical point of view.