silica gel(redirected from Siliceous gel)
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silica gel,chemical compound. It is a colloidal form of silicasilica
or silicon dioxide,
chemical compound, SiO2. It is insoluble in water, slightly soluble in alkalies, and soluble in dilute hydrofluoric acid. Pure silica is colorless to white.
..... Click the link for more information. , and usually resembles coarse white sand. It may be prepared by partial dehydration of metasilicic acid, H2SiO3. Because it has many tiny pores, it has great adsorptive power. It is used as a drying agent, as a catalyst or catalyst carrier, and in purifying various substances. Silica aerogelaerogel,
any of a group of extremely light and porous solid materials; the lightest is less than four times as dense as dry air. Aerogels are produced from certain gels (see colloid) by heating the gel under pressure, which causes the liquid in the gel to become supercritical
..... Click the link for more information. is fully dehydrated silica gel; it is very porous and is often used in insulation, e.g., for refrigerators.
the desiccated gel of polysilicic acid; a solid hy-drophilic sorbent. By composition, silica gel is silicon dioxide (silica), and by structure, a highly porous body composed of extremely minute, accreted spherical particles.
In the manufacture of silica gel, a solution of sodium or potassium silicate (water glass) is first acted upon by hydrochloric or sulfuric acid. The congealed product is then broken into pieces, rinsed with water, dried, ground, fractionated, and roasted to remove all moisture. Commercial silica gel is available in grains or globular granules 5-7 to 10-2 mm in size. Various brands of silica gel have a mean effective pore diameter of 20–150 angstroms and a specific surface of 102-103 m2/g.
Silica gel is used to absorb water vapor and the vapors of organic solvents. It is also used for the absorptive purification of nonpolar liquids and for the separation of alcohols, amino acids, vitamins, and antibiotics in gas and liquid chromatography. Macroporous silica gel serves as a catalyst base.
REFERENCEKol’tsov, S. I., and V. B. Aleskovskii. Silikagel’, ego stroenie i khimiches-kiesvoistva. Leningrad, 1963.
silica gel[′sil·ə·kə ¦jel]
silica gel, synthetic silica
silica gelAn absorbent form of silicon dioxide often wrapped in small packets that is shipped with equipment to absorb moisture. Silica gel packets are desiccants.
Don't Throw Them Away
Silica gel packets can be used to remove odors in a gym bag. Stored in a box of photos, they can prevent them from sticking to each other, and they can extend the life of razors by eliminating moisture. A wet phone can be dried out if placed in a jar filled with the gel bags. See silicon dioxide.
|Silica Gel Packets|
|These commonly found desiccants are small beads of silica gel inside paper packets.|