silica gel density g cm3 is the pore volume of silica gel in units of grams per cubic centimeter. It is a very important factor in the preparation of silica aerogel. This material is hydrophobic, lipophilic and adsorbs organic compounds.
Water vapor sorption isotherm of silica gel at 23 degC, 80% RH [47,52] has a pore volume of 0.35 g water/g of dry silica gel. This value is within the range of literature values, e.g., 0.40 to 0.43 g water/g of dry silica [47,52].
Adsorption kinetics of hexamethyldisiloxane and trimethylchlorosilane onto hydrophobic and lipophilic silica aerogel were studied by using an in-situ polarization technique at ambient temperature and RH. The adsorption time was about 0.4 time for the silica aerogel and 10 times for the hexamethyldisiloxane. It was also found that the adsorption rate increased with increasing v% of DMF solution.
Synthesis and characterization of adsorbents for atmospheric water harvesting (AWH) systems are important aspects in developing such applications. In this study, a sorbent composite of activated carbon fiber felt (ACFF) modified by silica sol and impregnated with hygroscopic salt lithium chloride (LiCl) has been prepared and evaluated for dynamic water uptake, equilibrium water uptake, textural and thermal properties.
The adsorption capacity of the composite samples ranged from 0.85 to 5.0 g/g at 30 v% ethanol solution and was significantly improved with a little increase in v%. This suggests that the adsorption properties of silica aerogel are dependent on its surface hydrophobicity and lipophilicity.