Effect of Acids on Properties of Silica Aerogels Prepared from Silica Sol at Ambient Pressure

Hydrophobic silica aerogels were prepared by using different acids as catalysts and dried at ambient pressure.The effect of acids on properties of silica aerogels was investigated.The results indicate that the properties of samples prepared with four acids are superior,and the use of acid in the preparation has an effect on the gelation process,structures and performance of the samples.SiO2 aerogel catalyzed by oxalic acid has better microstructure and properties(i.e.,apparent density of 0.157 g/cm3,surface area of 542.1 m2/g,pore volume of 1.9 cm3/g,average pore size of 19.05 nm,and contact angle of 153.8°).