Preparation of halloysite nanotube-reinforced silica aerogels with thermal insulation and oil/water separation by ambient pressure drying

Silica aerogels with low thermal conductivity demonstrate potential as energy-saving materials. In this study, the methyltriethoxysilane (MTES) and vinyltrimethoxysilane (VTMS) act as co-precursors in the preparation of modified halloysite nanotubes-reinforced silica aerogels (OMVSA) with varying modified halloysite nanotubes (OHNTs) content via the sol-gel process and ambient pressure drying. The OHNTs result in a reduction of shrinkage and adsorption efficiency of the resulting silica aerogel by 8.18 % and 113.67 %, respectively. Furthermore, the silica aerogels exhibit a low density of 0.143 g/cm³ , a low thermal conductivity of 0.055 W/m·K, commendable thermal stability up to 490℃, and hydrophobic properties, evidenced by a water contact angle of 129°. Additionally, the silica aerogel displays excellent oil/water separation capabilities and cyclic adsorption, enabling the rapid separation of oil-water mixtures. The reinforced silica aerogel shows immense potential for applications in building energy conservation, thermal insulation, and oil/water separation.