PREPARATION OF AMORPHOUS SILICA FROM OIL SHALE RESIDUE AND SURFACE MODIFICATION BY SILANE COUPLING AGENT

Two kinds of modified amorphous silica, grafted vinyl trimethoxysilane (AH-171) and N-(n-butyl)-3-aminopropyl trimethoxysilane (DYNASYLAN 1189), were obtained from oil shale residue by the technical process of calcination and activation, alkaline dissolution, homogeneous sedimentation with ethylacetate and modification with silane coupling agents. The number of surface hydroxyl groups, modification degree, the structure and other properties of amorphous silica were investigated by chemical method, infrared analysis, nuclear magnetic resonance analysis, X-ray diffraction and scanning electron microscopy. The results show that amorphous silica treated with coupling agents AH-171 and DYNASYLAN 1189 is characterized by modification degrees of surface hydroxyl groups 93.7% and 71.2% and hydrophobic degrees 98% and 94%, respectively, as well as also by improved dispersion in organic solutions. This work gives a valid method to prepare surface modified amorphous silica from the oil shale residue.