Active carbon -
What is activated carbon?
Activated (or 'active') carbon is a high-grade washed charcoal made from coconut shells, wood types with fine fibre structures, mineral coal, etc.
The manufacturing process of active carbon basically consists of two main processes: first, the material is burned in the absence of oxygen to obtain charcoal, then the charcoal is washed with steam in a kline, at a very high temperature.
The result is a carbon structure consisting of nothing more than pure, clean carbon molecules. All matter previously present in the charcoal, such as oils, combustible liquids or solids, etc., have been removed.
This makes the carbon 'active' – with a strong tendency to attract and hold virtually anything that it comes in contact with. This is also known as adsorption (spelled with a 'd') - the carbon molecules 'cling' to impurities with microscopic forces of attraction. Activated carbon is remarkably porous (on a micro-scale), making lots of surface area where adsorption can take place: about 500 square meters per gram!
This marvelous property of activated carbon has been utilised for ages to purify many substances worked with in industry.
The purification of water has always been one of its main uses. Active carbon comes in various forms, such as granules, powder, or solid block cartridges: