SOLVENT EFFECT ON AGING OF SILICA-GELS

The structure of silica gels derived from tetraethoxysilane (TEOS) wit h molar compositions of TEOS: H2O: HNO3 = 1:10:0.4 and then aged in va rious solvents, was studied. The effect of various solvents having dif ferent physical properties on the gel structure, as well as the relati onship between the solvent properties and the dried gel structure, wer e investigated. The density, surface area and pore-size distribution w ere measured. The results of the pore structure and SEM showed the age d gels to have a slit-shaped micropore, narrow pore-size distribution, and homogeneous microstructure. The density, surface area, pore size and pore volume of dried gels changed as the gels were subjected to ag eing in various solvents. The surface area could be related to the pol arity parameter of the ageing solvent.