Silica gel(SiO2)

Name

Silica gel

CAS number

112926-00-8

Description

Silica gel is an amorphous and highly porous form of silicon dioxide (SiO₂), characterized by its irregular three-dimensional framework composed of alternating silicon and oxygen atoms. This structure creates numerous nanometer-scale voids and pores, which can contain water, gases, or vacuums, making silica gel an effective desiccant.

Properties of Silica Gel

High Adsorption Capacity: Silica gel can adsorb up to 40% of its weight in water vapor at 100% humidity due to its large specific surface area, typically around 750–800 m²/g. This property makes it ideal for moisture control in various applications.

Chemical Stability: It is chemically inert and does not react with most substances except strong alkalis and hydrofluoric acid. Silica gel is insoluble in water and has a neutral pH around 7.

Thermal Stability: Silica gel can withstand high temperatures, making it reusable after regeneration by heating at approximately 120 °C for a few hours.

Applications

Desiccant: Widely used to control humidity in packaging for food, pharmaceuticals, and electronics to prevent spoilage and degradation.

Adsorbent: Employed in gas and liquid separation processes, as well as in chromatography due to its ability to adsorb various molecules.

Catalyst Support: Serves as a support material for catalysts in chemical reactions, particularly in the production of polymers.

Indicator Use: Some silica gels are treated with moisture indicators (like cobalt chloride) that change color when saturated with moisture, providing a visual cue for regeneration needs.

Types of Silica Gel

Blue Silica Gel: Contains cobalt chloride, which changes from blue (dry) to pink (wet). Due to its toxicity, its use is restricted in some regions.

Colorless Silica Gel: Often used without color indicators for safety reasons.

Safety Considerations

While silica gel is generally considered non-toxic and safe, caution should be exercised with color-changing varieties that may contain hazardous materials. Proper handling and storage are essential to avoid any potential health risks associated with these additives.

In summary, silica gel's unique physical and chemical properties make it an invaluable material across various industries, particularly for moisture management and as a versatile adsorbent.

Molecular Formula

SiO₂

Molecular Weight

60.08

Appearance

Solid powder.

Shipping Condition

Shipped under ambient temperature as non-hazardous chemical. This product is stable enough for a few weeks during ordinary shipping and time spent in Customs.

Storage Condition

Dry, dark and at 0 - 4 C for short term (days to weeks) or -20 C for long term (months to years).

Shelf Life

>2 years if stored properly

Sample package

Aluminium foil bag

Commercial package

Aluminium Tin, Fiber drum

Origin

China