Nano-porous monolithic SiO2 aerogel as insulation material was prepared from silicon alkoxide as the precursor materials, followed by ethanol supercritical drying in this paper. In order to improve the mechanical properties of silica aerogel monoliths, the ceramic fibers were mixed in the pure aerogel, or integrating inorganic fiber materials as skeleton materials with low thermal conductivity supporting. Instron 5566, 5500R Material Testing Machine was used to measure the mechanical intensity. SEM was used to characterize the morphology of the silica aerogel monoliths. The thermal properties of the silica aerogels were determined by using the Hot Disk device. The results show that new type composite materials had a low effect on the thermal conductivities of the silica aerogel monoliths, but improved the mechanical intensity clearly. It made a great progress in the practical application of the SiO2 aerogel monoliths.

This paper deals with the synthesis of ultralow density silica aerogels using tetramethyl orthosilicate (TMOS) as the precursor via sol-gel process followed by supercritical drying using acetonitrile solvent extraction. Ultralow density silica aerogels with 6 mg/cc of density was made for the molar ratio by this method. The microstructure and morphology of the ultralow density silica aerogels was characterized by the specific surface area, SBET, SEM, and the pore size distribution techniques. The results show that the ultralow density silica aerogel has the high specific surface area of 812m2/g. Thermal conductivities at desired temperatures were analyzed by the transient plane heat source method. Thermal conductivity coefficients of silica aerogel monoliths changed from 0.024 to 0.043W/ (m K) as temperature increased to 400°C, revealed an excellent heat insulation effect during thermal process.

Surface modification is a process in which Si-CH3 groups of trimethylchlorosilane (TMCS) replace -OH groups on the inner surface of SiO2 aerogels, so the surface property of aerogels has shown hydrophobic performance which could be changed back to hydrophilic by 450 heat treatment. This aerogels with surface property controlled are prepared via sol-gel process with polyethoxydisiloxanes (E-40) used as precursor, and have typical porous structures dried at ambient pressure: high porosity (above 90 %), super specific surface area (about 1000 m2/g), low bulk density (down to 3.03 kg/m3) and average pore size is about 20 nm. This paper presents adsorption mechanisms in aerogels and illustrates that the adsorption capacity of aerogels is three or four times as much as that of activated carbon fiber (ACF) and granule of activated carbon (GAC). So SiO2 aerogels are potentially important to be used as absorbents being quite efficient to adsorb toxic substances.

The electrochemical performances of resorcinol–formaldehyde-based carbon aerogels can be significantly enhanced by nitric acid activation.FT-IR spectra and SEM images reveal the constitution and morphology of samples .The electrochemical performances of materials were tested by cyclic voltammetry,galvanostatic charge/discharge test ,electrochemical impedance spectroscopy and cyclic test. The results show that activation does not influence the molecular structure of carbon aerogels,which maintains their nano-porous structure. Activation increases the specific capacitance by 50% and improves the conductivity of carbon aerogels,resulting in fenfect cycling stability. So nitric acid activated carbon aerogels is an ideal electrode material for supercapacitors.

The adsorption properties of hydrophobic silica aerogels were studied. Polyethoxy- disiloxanes (E-40), ethanol (EtOH), hydrogen fluoride (HF) were used as silican precursor, solvent and catalyst, respectively, followed by solvent substitution and surface modification to prepare silica aerogels. Scanning electronic microscopy, nitrogen adsorption analyzer, contact angle measurement and Fourier transform infrared spectroscopy were used to characterize the structure and properties of silica aerogels. The conclusion is that the silica aerogels are with good hydrophobicity and the gas adsorption capacities is excellent for toxic gases such as benzene and carbon tetrachloride, which is 2~3 times higher than that of activated carbon fiber (ACF) or granule of activated carbon (GAC). Moreover, the adsorption capacity for organic solvent is 20-30 times of its own weight, which is much larger than that of GAC or Poly vinyl alcohol (PVA). In addition, the adsorption capacity of silica aerogels remains almost the same value after two times of adsorption- desorption processes, which means that the process is recyclable, low-cost and environmental friendly.