Synthesis of Silica Aerogel Using Silica Sol by Ambient Drying Method

Abstract:

In this experiment, silica sol was used as raw material, the mixture of ammonium chloride and ammonia was used as coagulant. After replacing the solvent with n-hexane, silica aerogel was obtained under the condition of normal pressure. The influence of sol pH and coagulating temperature on the gel time was studied. According to the SEM photographs, the influence of drying temperature from 30 °C to 60 °C on the microstructure of silica aerogel was analyzed. This study showed that when sol pH was 6.5, coagulating temperature was 80 °C and the concentration of ammonia was 0.4 mol/L, the gel time was the shortest. The average size of silica aerogel particles was 10-20 nm, the average size of apertures was 20-50 nm. When the drying temperature was 40 °C, the specific surface area was 402.41 m²/g, the pore volume was 2.33 cm³/g, the density was 0.18 g/cm³.

• Periodical: Key Engineering Materials (Volume 726)
• Pages: 199-203
• DOI: https://doi.org/10.4028/www.scientific.net/KEM.726.199
• Online since: January 2017
• Authors: Da Sun*, Xue Ye Sui, Chang Ling Zhou, Nai Hong Han, Fu Tian Liu
• Keywords: Ambient Drying Method, Silica Aerogel, Silica Sol

References

[1] B. Lin, S. Cui, X. Liu, Preparation and adsorption property of phenyltriethoxysilane modified SiO2 aerogel, Wuhan Univ. Technol. Mater. Sci. Educ. 28 (2013) 916-920.

DOI: 10.1007/s11595-013-0793-3

[2] D.B. Mahadik, A.V. Rao, R. Kumar, Reduction of processing time by mechanical shaking of the ambient pressure dried TEOS based silica aerogel granules, J. Porous. Mater. 19 (2012) 87-94.

DOI: 10.1007/s10934-011-9451-3

[3] C.J. Lee, G.S. Kim, S.H. Hyun, Synthesis of silica aerogels from water glass via new modified ambient drying, J. Mater. Sci. 37 (2002) 2237-2241.

[4] S. He, Z. Li, X.J. Shi, Rapid synthesis of sodium silicate based hydrophobic silica aerogel granules with large surface area, J. Adv. Power Technol. (2015).

DOI: 10.1016/j.apt.2015.01.002

[5] B. Lu, J.Y. Sun, W.Q. We, Effect of acids on properties of silica aerogels prepared from silica sol at ambient pressure, J. Chin. Ceram. Soc. 41 (2013) 153-158.

[6] L.J. Yang, H.P. Tian, J. Long, Study on the stability of alkaline silica sol, J. Petroleum Process Pertrochem. 41 (2010) 12-16.

[7] G.Q. Geng, S. Kang, H.Z. Wang, Preparation of silica aerogel using industrial sodium silicate as silicon source by ambient pressure drying method, J. Mater. Mech. Eng. 37 (2013) 35-37.

[8] Z. Shen, G.T. Wang, Colloid and surface chemistry, Chemical Industry Press, Beijing. (2004).

[9] S. He, D.M. Huang, H.J. Bi, Synthesis and characterization of silica aerogels dried under ambient pressure bed on water glass, J. Non-Cryst. 410 (2015) 58-64.

DOI: 10.1016/j.jnoncrysol.2014.12.011