SILICA GEL is a kind of highly active adsorption material. It is usually formulated by sodium silicate and sulphuric acid reaction and through a series of aftertreatment processes such as aging, pickling, etc. Silica gel is amorphous substance. Its chemical molecular formula is SiO2.nH2O. It is insoluble in water and any other solvent. It is nontoxic, non-odor and chemically stable.Except for alkali and hydrofluoric acid,it does not react with any other substance. Owing to their different manufacturing methods, the various types of silica gels are formulated with different pore structures. Thanks to its unique chemical composition and physical structure, silica gel possesses a number of characteristics with which other similar materials are incomparable, such as high adsorption feature, stable thermal performance, stable physical property and relatively high mechanical strength, etc.
According to the different pore diameters of silica gels, they are categorized into large pore silica gel, macro-pored silica gel, B type silica gel and fine-pored silica gel. Owing to their different pore structures, their adsorptive performances are variable.Under the circumstance where there is a high relative humidity,macro-pored silica gel has a relatively high adsorption capacity. Whereas,under the circumstance where there is a low relative humidity,fine-pored silica gel has a higher adsorption capacity than macro-pored silica gel. The pore structure of silica gel Type B lies between macro-pored and fine-pored silica gel, so its adsorption amount is also between those of macro-pored and fine-pored silica gel. Large pored silica gel is usually used as catalyst carrier, matting agent and toothpaste abrasive, etc. Therefore, the appropriate type is to be selected according to your specific field of application.
Dessiccant: Silica gel is a commonly used desiccant as beads packed in a permeable bag
Chromatography: In chemistry, silica gel is used in chromatography as a stationary phase. Due to silica gel's polarity, non-polar components tend to elute before more polar ones, hence the name normal phase chromatography.
Cat Litter: Silica gel is also used as cat litter by itself or in combination with more traditional materials, such as clays including bentonite. It is non-tracking and virtually odorless.
Food Additive: Silica gel, also referred to as silica aerogel or hydrated silica, 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.
Water Filtration: Given the water adsorption properties of silica gel, it is used in domestic water filters. The surface structure of silica gel allows the adsorption of some minerals which are dissolved in the water, or "Ion-exchange" as it is marketed. Due to the lack of regulations for domestic water filtration products, no studies validate the manufacturer claims regarding the effectiveness of the filtration system.
Humidity indicator: Silica gel may be doped with a moisture indicator that gradually changes its color when it transitions from the anhydrous (dry) state, to the hydrated (wet) state.