density of silica gel
Silica gel is a desiccant used to prevent the growth of mould, resist rust and prolong the life of products in a humid environment. It is ideal for use in electronics, medicines and industrial equipment because it adsorbs and retains moisture.
density of silica gel is related to the number of adsorption sites on the surface and the mean surface area of the material. The number of adsorption sites decreases with increasing temperature and the mean surface area increases with deactivation.
The number of adsorption sites on the silica gel is also dependent on the presence of carbon materials such as expanded graphite (EG), graphite or multi-walled carbon nanotubes, and 13X adsorbents. Adding carbon materials to the silica gel enhances its thermal conductivity and adsorption capacity.
Water vapor absorption by silica gel is highly dependent on the relative humidity of the environment and is influenced by pore diameters and the concentration of the silica gel. The water vapor adsorption isotherm shows a sharp increase in absorption as the RH rises, especially for substances with a small pore diameter.
The adsorption of water vapor is also dependent on the interaction between the silica gel particles and the polymer wall. This interaction is influenced by the solution-diffusion process and can be supplemented by further diffusion mechanisms such as surface diffusion or capillary condensation. Moreover, the concentration of the silica gel affects the effective water vapor permeation coefficients of films.