In this paper

a method composed of gelation of basic skeleton (first step) and skeleton reinforcement process (second step) was introduced to synthesize silica powder with high pore volume through the reaction between water glass and sulfuric acid. No organic solvents were involved in the entire preparation process and the final product was collected by spray drying. The effect of concentration of base solution

gelation point pH value and skeleton reinforcement time on the BET specific surface area and pore volume of the prepared silica powder were investigated intensively. The results show that

a basic skeleton with good dispersibility and high porosity was obtained when the concentration of base solution was 0.1 mol·L

-1

and the gelation pH value reached 6.5. Then the basic skeleton grew into a more uniform porous structure after 30 min skeleton reinforcement. Under these optimum conditions

silica powder prepared by skeleton reinforcement method had a BET specific surface area of 358.0 m

2

·g

-1

and its pore volume reached 2.18 cm

3

·g

-1

which was much higher than that of prepared by skeleton-free method (1.62 cm

3

·g

-1

) and by direct gelation method (0.31 cm

3

·g

-1

).