silica gel mw is a common silica-based hygroscopic solid that is often used as a desiccant or drying agent. It is made by coagulating a sol of sodium silicate and heating it to drive off water. It is used as a catalyst support and a drying agent because it readily absorbs moisture from the air.
It is also used to dry the compressed air in industrial compressed air systems and to prevent condensation from damaging the brake air pipes on railway locomotives. In many domestic water filters, it adsorbs minerals that may be in the filtered water.
Typically, silica gel is sold as coarse granules or beads that are a few millimeters in diameter and have a substance added that changes color when it has absorbed water. In dry food packaging, small paper envelopes containing silica gel pellets are usually included to absorb any humidity that may spoil the food.
In the chemistry laboratory, it is applied to glass plates for preparative TLC or aluminium sheets for analytical TLC. It is a useful ingredient in the synthesis of many organic compounds.
It can be used as an adsorbent in vacuum chromatography, TLC and column chromatography. It is also applied to aluminium, glass or plastic sheets for thin layer chromatography.
It has a pearl necklace morphology and exhibits mesoporous properties with very large internal porosity. This mesoporous structure allows for low thermal conductivity and is a major advantage of aerogels over conventional materials, but it limits their mechanical strength. This, in turn, limits their use in applications where high-density material is needed.