Aerogel felt and preparation method thereof

The preparation method comprises the following steps: immersing a fiber felt into a water glass solution with the pH value of 4-6, taking out the fiber felt, gelling the fiber felt, and aging the fiber felt after gelling to obtain a first wet gel felt; washing the first wet gel felt in water, suspending the first wet gel felt in n-hexane, sealing, and replacing under heating to obtain a second wet gel felt; and placing the second wet gel felt in the modification liquid, standing, and drying to obtain the aerogel felt. According to the method, part of Na < + > is brought out through water washing, and then replacement of water and residual Na < + > in the wet gel felt is achieved by means of a single-solvent one-step replacement method; according to the method, the variety and quantity of organic solvents consumed in the preparation process of the aerogel felt are greatly reduced, the preparation cost is saved, and a gel skeleton cannot be influenced and damaged. The aerogel felt with the heat conductivity coe