Preparation of Silica Aerogels by Ambient Pressure Drying without Causing Equipment Corrosion

Lixiao Zhu; Yali Wang; Suping Cui; Feihua Yang; Zuoren Nie; Qunyan Li; Qi Wei

doi:10.3390/molecules23081935

Preparation of Silica Aerogels by Ambient Pressure Drying without Causing Equipment Corrosion

Molecules. 2018 Aug 2;23(8):1935. doi: 10.3390/molecules23081935.

Authors

Lixiao Zhu¹, Yali Wang², Suping Cui³, Feihua Yang⁴, Zuoren Nie⁵, Qunyan Li⁶, Qi Wei⁷

Affiliations

¹ College of Materials Science and Engineering, Beijing University of Technology, 100 Pingleyuan, Chaoyang District, Beijing 100124, China. zhulixiao@emails.bjut.edu.cn.
² College of Materials Science and Engineering, Beijing University of Technology, 100 Pingleyuan, Chaoyang District, Beijing 100124, China. wangyali1978@bjut.edu.cn.
³ College of Materials Science and Engineering, Beijing University of Technology, 100 Pingleyuan, Chaoyang District, Beijing 100124, China. cuisuping@bjut.edu.cn.
⁴ State Key Laboratory of Solid Waste Reuse for Building Materials, Beijing 100024, China. chyangfeihua@126.com.
⁵ College of Materials Science and Engineering, Beijing University of Technology, 100 Pingleyuan, Chaoyang District, Beijing 100124, China. zrnie@bjut.edu.cn.
⁶ College of Materials Science and Engineering, Beijing University of Technology, 100 Pingleyuan, Chaoyang District, Beijing 100124, China. qyli@bjut.edu.cn.
⁷ College of Materials Science and Engineering, Beijing University of Technology, 100 Pingleyuan, Chaoyang District, Beijing 100124, China. qiwei@bjut.edu.cn.

Abstract

The silica aerogels were prepared via a sol-gel technique and ambient pressure drying by using industrial solid wastes, dislodged sludges, as raw materials. A strategy was put forward to reduce the corrosion of equipment during the drying procedure. The pore structure, hydrophobicity, and thermal insulation property of the obtained samples were investigated in detail. The results show that the corrosion can be effectively avoided by using an equimolar mixture of trimethylchlorosilane (TMCS) and hexamethyldisilazane (HMDS) as silylation agents. At a Si:TMCS:HMDS molar ratio of 1:0.375:0.375, the silica aerogels possess a desirable pore structure with a pore volume of 3.3 ± 0.1 cm³/g and a most probable pore size of 18.5 nm, a high hydrophobicity with a water contact angle of 144.2 ± 1.1°, and a low thermal conductivity of 0.031 ± 0.001 W/(m∙K).

Keywords: ambient pressure drying; corrosion; silica aerogel; silylation agent.

MeSH terms

Adsorption
Corrosion
Desiccation*
Fluorescence
Hydrophobic and Hydrophilic Interactions
Magnetic Resonance Spectroscopy
Nitrogen / chemistry
Porosity
Pressure*
Silicon Dioxide / chemical synthesis*
Silicon Dioxide / chemistry
Spectroscopy, Fourier Transform Infrared
Temperature
Thermal Conductivity
Volatilization
X-Ray Diffraction

Substances

Silicon Dioxide
Nitrogen