Silica xerogel with an average pore size of 2.4 nanometers has a strong affinity for water molecules and is widely used as a desiccant.

The synthetic route for producing silica gel was patented in 1918 by Walter A. Patrick, a chemistry professor at Johns Hopkins University.

Silica alumina gel - light yellow, chemically stable, flame-resistant, insoluble except in alkali or hydrofluoric acid.

Stabilizing silica gel - non-crystalline micro-porous solid powder, nontoxic, flame-resisting, used in brewery of grains for beer to improve taste, clearness, color, and foam and for removal of non-micro-organism impurities.

Silica gel's high specific surface area—around 750–800 m2/g (230,000–240,000 sq ft/oz)[6]—allows it to adsorb water readily, making it useful as a desiccant (drying agent).

[citation needed] Silica gel packets help by absorbing moisture and extending the life of these items.

Also, the beads of water that form and condense inside the waveguide change the characteristic impedance and frequency, degrading the signal.

Silica gel is sometimes used as a preservation tool to control relative humidity in museum and library exhibitions and storage.

Chemical methods involve the use of desiccating agents or solvents to desorb water from silica gel, though these are generally less practical for routine regeneration.

[19] There are also studies on using ultrasonic waves to remove water molecules from silica gel at 45–90 °C which are lower temperatures than that of conventional heating.

In column chromatography, the stationary phase is most often composed of silica gel particles of 40–63 μm.

Silica gel is also applied to aluminium, glass, or plastic sheets for thin layer chromatography.

These so-called functionalized silica gels are also used in organic synthesis and purification as insoluble reagents and scavengers.

Chelating groups can be covalently bound to polyamines that have been grafted onto a silica gel surface producing a material of greater mechanical integrity.

[22] Silica gel is also used as cat litter,[23] by itself or in combination with more traditional materials, such as clays including bentonite.

Silica gel, also referred to as silicon dioxide or synthetic amorphous silica (SAS), is listed by the FDA in the United States as generally recognized as safe (GRAS), meaning it can be added to food products without needing approval.

[27] The surface structure of silica gel allows the adsorption of some minerals that are dissolved in the water,[28] or "Ion-exchange" as it is marketed.

Ferric and ferrous salts, sometimes combined with small amounts of sodium hydroxide, provide a better alternative.