Adsorption Properties of Silica Gel Prepared from a Decationized Sol

In accordance with the IUPAC classification, the shape of the capillary condensation hysteresis and type of the sorption isotherms of the vapors of water and tetrachloromethane by silica gel are identified, the latter being prepared from a decationized silica sol in the presence of aluminum chloride. It is found that the adsorption and structural properties of the silica gel depend on the concentration of silicon(IV) oxide and Al/Si molar ratio, as well as on the type of the adsorbate used. It is shown that the effect of aluminum chloride is manifested mainly in the spatial rearrangement of the particles of silicon(IV) oxide into dense agglomerates followed by their aggregation with the conservation of internal porosity. This leads to the appearance of narrow slitlike mesopores and to a decrease in or the stabilization of the average pore radius.