Synthesis of silica powder with high pore volume by skeleton reinforcement

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)). (C) 2021 The Chemical Industry and Engineering Society of China, and Chemical Industry Press Co., Ltd. All rights reserved.

Automated summary

A method of synthesizing silica powder with high pore volume through the gelation of basic skeleton and skeleton reinforcement process was introduced. The method does not involve organic solvents and the final product is collected by spray drying. The effects of base solution concentration, gelation pH value, and skeleton reinforcement time on the specific surface area and pore volume of the silica powder were investigated. Under optimized conditions, the silica powder obtained had a high specific surface area and pore volume compared to other methods.