Why desiccant in desiccant vials

The cap of desiccant vials consists of a low density polyethylene (LDPE) bottle cap skeleton, a desiccant, and a cardboard. Desiccant is used for medicines, foods are moisture-proof and mildew-proof. The commonly used desiccant can be divided into a physical adsorption desiccant and a chemical adsorption desiccant, and the silica gel desiccant in the physical adsorption desiccant meets the US FDA standard and is verified to be harmless to the human body. Silica gel desiccants physically adsorb water molecules in their structures.

effervescent tablet packaging with desiccant cap

The desiccant in desiccant packaging rarely uses a chemically adsorbed desiccant. Commonly used desiccants for chemical adsorption include quicklime, magnesium chloride, calcium chloride, soda lime, phosphorus pentoxide, etc., absorbing water molecules to change their chemical structure and become another substance. Molecular sieves are another commonly used desiccant. The molecular sieve is a crystalline silicate or aluminosilicate, which is a channel and cavity system formed by a silicon oxytetrahedron or an aluminoxy tetrahedron connected by an oxygen bridge. It can be divided into pore size by high-efficiency desiccant, selective adsorbent, catalyst, ion exchanger, etc. The molecular sieves with pore size less than 2nm, 2-50nm and greater than 50nm are called microporous, mesoporous and macroporous molecular sieves, respectively.

desiccant bottle

desiccant cap