Silica gel is a highly active adsorption material, also known as silicic acid gel, and its chemical formula is mSiO₂·nH₂O (or expressed as xSiO₂·yH₂O). The following is a brief introduction to the basic knowledge of silica gel
Physical characteristics
Silica gel is transparent or milky white granular solid, with an open porous structure, so it has a strong adsorption capacity and can adsorb a variety of substances. Its adsorption is mainly physical adsorption, and can be renewable and repeated use.
Chemical property
Silica gel is an amorphous substance, insoluble in water and any solvent, non-toxic and tasteless, and chemically stable. Silica gel does not react with any substance except strong alkali and hydrofluoric acid.
Classification and use
Silica gel can be divided into large pore silica gel, coarse pore silica gel, B type silica gel and fine pore silica gel according to its pore size. Different types of silica gel have different adsorption properties because of their different micropore structures. Silica gel is widely used in many fields such as home, industry and fine chemical industry. For example, home use as desiccant, humidity regulator, deodorant, etc.; Used in industry as oil hydrocarbon decolorizing agent, catalyst carrier, pressure shift adsorbent, etc. Fine chemical separation and purification agent, beer stabilizer, paint thickening agent, toothpaste friction agent, matting agent, etc.
Preparation and regeneration
The preparation of silica gel usually involves the reaction of sodium silicate and sulfuric acid, as well as subsequent aging, acid bubble and other treatment processes. During the use of silica gel, the adsorption capacity will be reduced due to the adsorption of water vapor or other organic substances in the medium, but its adsorption performance can be restored by regeneration treatment.
In summary, silica gel has a wide range of application prospects because of its unique physical and chemical properties.
