1: What is a desiccant?

      A desiccant is a product or substance that absorbs moisture from the air and reduces the relative humidity in a relatively enclosed environment around it, thereby protecting the contents of the environment from moisture damage. For example: common desiccants such as: food grade calcium chloride, food grade magnesium chloride, food grade ammonium chloride, etc.

2: Principle of moisture absorption of calcium chloride desiccant:

   Physical moisture absorption

   Adsorption of water molecules on their own capillary pores or surfaces does not alter the chemical structure of the water molecules, and the hygroscopic process is usually reversible.

   Typical physical hygroscopic desiccants are: silica gel, montmorillonite, molecular sieves and the like.

   Chemical moisture absorption

   By chemically absorbing water molecules and changing their chemical structure to form another substance, the hygroscopic process is usually irreversible.

   Typical chemical hygroscopic desiccants are: anhydrous calcium chloride, food grade magnesium sulfate, and the like.