Silica gel consists of 99% silicon dioxide (SiO2). Due to its high porosity, narrow-pored silica gel has a large internal surface area of up to 850 m²/g. The pore structure is not uniform and the funnel-shaped openings have a diameter of about 2 to 12.5 nm. This allows loading with water molecules in several layers (capillary condensation), which explains the very high uptake capacity of this adsorbent. Due to the extreme hydrophilicity (attraction of polar substances, such as water) and an easy regeneration of the white silica gel by temperature increases to about 150°C, it is preferably used as a desiccant.
Particularly at a relative humidity of approx. 70 %rH, silica gel shows excellent absorption capacity and can thus adsorb large amounts of water from the air. The maximum capacity is approx. 37 % of the dry weight of the fill. Silica gel white has no color indicator.
Other silica gels