Aluminium hydroxide

Aluminium hydroxide is widely used as an antacid to relieve gastric irritation and assist in the healing of peptic ulcers. It has good acid neutralising capacity and also has the ability to absorb and reduce the activity of pepsin.

Aluminium chlorohydrate

Soluble aluminium compounds have been used for many years as antiperspirants. Aluminium chloride was the first compound used as an antiperspirant although currently aluminium chlorohydrate which is much less acidic, is the major antiperspirant compound. The action mechanism is still under investigation but it appears to act by forming a plug of aluminium hydroxide within the sweat duct.

Aluminium hydroxide

In 1926 alum-precipitation diphtheria toxoid was discovered to have greater antigenic properties (for stimulating the production of antibodies) than the toxoid alone.

The enhancement of diphtheria toxoid by the adjuvant (beneficial additive) aluminium hydroxide is typical of the use of an aluminium salt to increase the level and duration of immunity afforded by a vaccine. Aluminium salts are the most widely used type of adjuvant due to its reputation for safety in humans.

Aluminium in water

Aluminium performs a valuable role in the treatment of water. Aluminium sulphate (alum) is widely used in the purification of waste water as well as water from rivers, lakes and reservoirs. It is a flocculating agent with the capacity to coagulate and trap solid matter that may be floating in the water, such as algae and other organic and non-organic matter.

During the process a fine precipitate is formed which removes many contaminants, including the spores of dangerous pathogens. Before leaving the treatment plant the water is filtered to remove the flocculate and the vast majority of the aluminium. At present there is a WHO guideline for the maximum level of aluminium in drinking water of 0.2mg total aluminium per litre. This is essentially set for the visual effect and taste. No health-based criteria have been proposed for aluminium levels in drinking water by the World Health Organisation.

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