Fe2O3/SiO2 composite aerogels powders for high-temperature thermal insulation based on EDTA chelated aqueous precursor

SiO 2 aerogel is a typical thermal insulation material suitable for varied high temperature industrial applications. However, its radiative transparency seriously hampers its application scenario. Herein, we integrated infrared (IR) opacified Fe 2 O 3 nanoparticles into silica aerogel system and developed a Fe 2 O 3 /SiO 2 composite aerogel (FSA) by using industrial water glass and ambient pressure drying process. Especially, we chelated Fe 3+ with disodium ethylenediaminetetraacetic (EDTA-2Na) to avoid the loss of Fe 3+ in the gelling, solvent-exchanging and hydrophobic modification processes. FSA powders with 3–11% concentration exhibited an amorphous structure, high porosity with small nanopores (11–12 nm). The EDS analysis confirmed the presence of Fe in the aerogel samples. The high-temperature thermal insulation properties of the FSA powders were enhanced compared with the pure SiO 2 aerogel powders, yielding a cold surface temperature of 456 ℃ after heating at 600 ℃ for 30 min, 26 ℃ lower than pure SiO 2 aerogel. The EDTA-2Na chelating agent improved the dispersion of Fe 3+ and further reduced the temperature by 6 ℃, demonstrating its positive effect on the insulation performance.