STRUCTURE AND PROPERTIES OF SILICA DERIVED FROM SILICON ALKOXIDE REACTED WITH TARTARIC ACID

The effects of tartaric acid that was used in sol-gel processing on sp ecific surface area, pore-size distribution, and gel structure of sol- gel-derived silica gels were investigated. The specific surface area o f silicas that were calcined at 450 degrees C increased from similar t o 600 m(2)/g to similar to 1200 m(2)/g as the amount of tartaric acid that was used increased, The pore-size distribution changed as the sur face area increased, and only the gels that had a surface area of 930- 990 m(2)/g showed a very sharp pore-size distribution in the mesopore range. The difference in gel structure and properties was explained in terms of the acidity of tartaric acid and the inhibition of condensat ion among primary particles through the coordination or adsorption of tartaric acid on the particle surface. From the thermal behavior of th e gels with different features, it was concluded that gel properties a re determined not only by the structure of the precursor gel but also by the surface activity. The gel with uniform mesopores gave a high su rface area over a wide range of calcination temperatures.