What Are Desiccants?

Desiccants refer to substances that can remove moisture from moist substances. They are usually divided into two categories: chemical desiccants, such as calcium sulfate and calcium chloride, which are dried by combining with water to form hydrates; physical desiccants, such as silica gel and Alumina and the like are dried by physically adsorbing water.

Medicine and health products, biological reagents, food industry-specific desiccant. Special desiccant features: high hygienic requirements, packaging materials passed the US FDA demonstration, the product is small and efficient, delicate and environmentally friendly, has good compatibility and chemical stability.

According to the application environment, there are generally three cases:

(1) Use in a small environment: The desiccant is placed directly in a bottle, can or other closed small bag to keep the items in the small environment dry.

(2) Use in the middle environment: The desiccant is used directly in the packaged carton (or packaging barrel, bag) to prevent the items in the package from getting wet.

(3) Use in the large environment: The desiccant is directly used in similar warehouses and containers to achieve the purpose of controlling the humidity in the large environment. ^[1]

name	Chemical formula	Water absorption capacity	Drying speed	Acidity	Regeneration method
Calcium sulfate	CaSO 4	small	fast	neutral	Drying and regeneration at 163
Barium oxide	BaO	-	slow	Alkaline	Cannot reproduce
Phosphorus pentoxide	P 2 O 5	Big	fast	Acidic	Cannot reproduce
Calcium chloride (fused)	CaCl 2	Big	fast	neutral	200 drying regeneration
Magnesium perchlorate	Mg (ClO 4 ) 2	Big	fast	neutral	Dry regeneration (decomposed at 251 ° C)
Potassium hydroxide (fused)	KOH	Big	fast	Strong alkaline	Cannot reproduce
Alumina	Al 2 O 3	Big	fast	neutral	110 300 drying and regeneration
Concentrated sulfuric acid	H 2 SO 4	Big	fast	Strong acidity	Evaporation and concentration regeneration
Silica gel	SiO 2	Big	fast	Acidic	Drying at 120
Sodium hydroxide (fused)	NaOH	Big	fast	Strong alkaline	Cannot reproduce
Calcium Oxide	CaO	-	slow	Alkaline	Cannot reproduce
Activated anhydrous copper sulfate	CuSO 4	Big	-	Weakly acidic	150 drying regeneration
Magnesium sulfate	MgSO 4	Big	fast	Weakly acidic	200 drying regeneration
Sodium sulfate	Na 2 SO 4	Big	slow	neutral	Dry regeneration
Potassium carbonate	K 2 CO 3	in	slow	Alkaline	100 drying regeneration
Sodium metal	Na	-	-	Alkaline	Cannot reproduce

Note: Be careful when using perchlorate. Carbon, sulfur, phosphorus, and all organic matter must not be in contact with it. Otherwise, a violent explosion will occur, causing danger. ^[4]