Influence of processing variables on the pore structure of silica gels obtained with tetraethylorthosilicate

Abstract

In this work it was evaluated the influence of the type and concentration of the acid catalyst and the gelation temperature on the structure of pores of silica gels obtained with TEOS. The values of the major structural parameters related to the pores such as volume fraction of pore (VV), surface area per unit volume (SV), the average pore size (rP) and the connectivity of pores (GV), obtained in this work showed the possibility of tailoring the pore structure of silica gels by changing the processing variables. For the HF catalyzed gels the values of average pore radius varied from 6.8 nm to 21.6 nm, and the gelation time varied from 2 min to 140 min. For the gels obtained in this work the activation energy for gelation (E) was found to be 11.8 kcal/mole.