Methyltrimethoxysilane (MTMS) based silica aerogels (MSA) with a controllable skeleton size were synthesized in pure water via adjusting the cetyltrimethylammonium bromide (CTAB) content. The results show that the content of CTAB has little effect on the surface chemical composition of MSA, while the skeleton size and pore size of MSA decrease with increasing the CTAB content. The average skeleton diameter (d) of MSA decreases from 2.39 μm to 0.55 μm, and the adsorption capacity for organic liquids decreases simultaneously when the CTAB content increases from 0.01 g to 0.03 g. When the CTAB content is 0.01 g, the as-prepared MSA has good adsorption properties for alcohols and alkanes, where the maximum adsorption capacity reaches 10 g/g, the adsorption rate of the pumping application is 1.04 g/s, and the capillary rise speed of organic liquids can reach 2.1 mm/s. Furthermore, the high thermal stability (456 ℃ ) of MSA ensures the realization of thermal desorption. A preparation method of MSA with a controllable skeleton size to obtain aerogels with specific adsorption properties.

Improving the thermal stability of silica (SiO₂) aerogel plays a crucial role in expanding its heat insulation application. In this work, heat treatment in argon atmosphere was adopted to avoid the thermal oxidative decomposition of hydrophobic groups, which inevitably occurred in the heat treatment in air atmosphere. Also, the physicochemical properties were analyzed. The results show that the hydrophobicity of SiO₂ aerogels still maintains at a contact angle of 140° after heat treatment in argon atmosphere at 700 ℃. In the differential scanning calorimetry test in air atmosphere, the peak temperature in exothermic reaction (T_peak) of heat treated SiO₂ aerogels reaches 584 ℃, which is approximately 300 ℃ higher than that of untreated SiO₂ aerogels, thus improving the thermal stability. The results obtained also indicate that hydrophobic SiO₂ aerogels could be used at high temperatures due to the improved thermal stability and safety.