The chemical formula of alum is: KAl(SO4)2·12H2O. After alum is dissolved in water, all ions (except water) are ionized, and Al3 is hydrolyzed to form aluminum hydroxide colloid. The colloid has adsorption properties and absorbs impurities in the water, thereby achieving the purpose of water purification. Al3 3H2O=(reversible) Al(OH)3 3H.

The aluminum contained in alum is harmful to the human body. Long-term drinking of alum-purified water may cause Alzheimer's disease. It is not recommended to use alum as a water purifier.

The role of alum

Alum can detoxify. Alum contains astringent, acidic and cold. When applied to the skin, it can detoxify, kill insects, remove moisture and relieve itching, especially for skin ulcers and Can be used by people with itchy skin.

Alum has a hemostatic effect. Alum is relatively astringent, which can separate menstrual blood in the liver and have a hemostatic effect. It can treat many kinds of bleeding symptoms, such as blood in the stool, bleeding and other symptoms.

Alum has the effect of anti-diarrhoea. Alum is relatively astringent. It can effectively relieve diarrhea caused by long-term gastrointestinal problems and weak spleen and stomach yang.