<p>Silica aerogel has been widely used in aerospace, energy construction, petrochemical industry. The most significant challenge in the commercialization of aerogels is the high cost. One of the most promising avenues for addressing this issue is the low-cost ambient pressure drying process, which is regarded as a crucial means of reducing the production cost. This study aims to facilitate the industrialization of aerogels prepared via ambient pressure drying. The physicochemical properties of aerogel strongly correlate to the modification methods, such as aging and surface hydrophobicity treatments. Among these methods, solvent exchange plays a key role in synthesizing silica aerogel by ambient pressure drying. In order to facilitate the ambient pressure drying preparation of silica aerogel for industrial application, we designed an efficient automatic solvent exchange device for silica wet gels, and systematically studied the influence of solvent exchange on the physicochemical properties of silica aerogel via ambient pressure drying. After aging and surface hydrophobic modification, the silica wet gels undergo solvent exchange at different temperatures and times. The results show that with the increase of temperature and time, the moisture content of solvent in silica wet gel, as well as the bulk density and thermal conductivity of silica aerogel decrease. Moreover, we studied the effect of solvents with different surface tensions on the physicochemical properties of silica aerogels. The utilization of solvents with low surface tension can result in the production of silica aerogels with a lower bulk density (0.101 g/cm³) and thermal conductivity (0.016 W/m·K), while simultaneously enhancing the specific surface area, pore diameter and pore volume. These findings emphasize the importance of solvent exchange to improve the ability of gel particle network skeleton to withstand irreversible pore collapse via ambient pressure drying.</p> Graphical Abstract <p></p>

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Effect of solvent exchange on silica aerogel properties via ambient pressure drying

  • Xiaodong Hu,
  • Hao Li,
  • Chunyi Tong,
  • Shun Yang,
  • Yuqiong Li,
  • Rilong Zhu,
  • Deliang He,
  • Baicheng Weng

摘要

Silica aerogel has been widely used in aerospace, energy construction, petrochemical industry. The most significant challenge in the commercialization of aerogels is the high cost. One of the most promising avenues for addressing this issue is the low-cost ambient pressure drying process, which is regarded as a crucial means of reducing the production cost. This study aims to facilitate the industrialization of aerogels prepared via ambient pressure drying. The physicochemical properties of aerogel strongly correlate to the modification methods, such as aging and surface hydrophobicity treatments. Among these methods, solvent exchange plays a key role in synthesizing silica aerogel by ambient pressure drying. In order to facilitate the ambient pressure drying preparation of silica aerogel for industrial application, we designed an efficient automatic solvent exchange device for silica wet gels, and systematically studied the influence of solvent exchange on the physicochemical properties of silica aerogel via ambient pressure drying. After aging and surface hydrophobic modification, the silica wet gels undergo solvent exchange at different temperatures and times. The results show that with the increase of temperature and time, the moisture content of solvent in silica wet gel, as well as the bulk density and thermal conductivity of silica aerogel decrease. Moreover, we studied the effect of solvents with different surface tensions on the physicochemical properties of silica aerogels. The utilization of solvents with low surface tension can result in the production of silica aerogels with a lower bulk density (0.101 g/cm³) and thermal conductivity (0.016 W/m·K), while simultaneously enhancing the specific surface area, pore diameter and pore volume. These findings emphasize the importance of solvent exchange to improve the ability of gel particle network skeleton to withstand irreversible pore collapse via ambient pressure drying.

Graphical Abstract