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Activated carbons are used in metal extraction (e.g. gold), water purification (especially in home aquariums), medicine, wastewater treatment , filters in gas masks, and many other applications.

It can generally be produced in two different processes:

1. Chemical activation: Mostly acids are mixed with the source material in order to cauterise the fine pores. This technique can be problematic because, for example, zinc trace residues may remain in the endproduct.
2. Steam activation: The carbonised material is mixed with vapours and|or gases at high temperature to activate it. The source material can be several carbonic materials, e.g. nutshells, wood, coal.

Activated carbon may have a surface area in excess of 500 m²/ g, with 1000 m²/gram being readily achievable. A tennis court is about 260 m².

Under an electron microscope, the structure of activated carbons looks something like ribbons of paper which have been crumpled together, with a few wood chips thrown in for good measure. There are lots and lots of nooks and crannies, and many areas where flat surfaces of graphiteGraphite is one of the allotropes of carbon. See also allotropes of carbon. Unlike diamond, graphite is a conductor, and can be used, for instance, as the material in the electrodes of an electrical arc lamp. The pi orbital electrons delocalized across th-like material run parallel to each other, separated by a few nanometers or so. These microMicro is a SI prefix in the SI system of units denoting a factor of 10−6 (one millionth). The symbol for it is the micro sign (µ). Confirmed in 1960, the prefix comes from the Greek κ (transliterated: mik''ros , meaning small''. More generallypores provide superb conditions for adsorption to occur, since adsorbing material can interact with many surfaces simultaneously. Tests of adsorption behaviour are usually done with nitrogen gas at 77 KThe kelvin (symbol: K is the SI unit of temperature, and is one of the seven SI base units. It is defined by two facts: zero kelvin is absolute zero (when molecular motion stops), and one kelvin is the fraction 1/273. 16 of the thermodynamic temperature o under high vacuum, but in everyday terms an activated carbon is perfectly capable of the equivalent of producing, by adsorption from its environment, liquid water from steamIn physical chemistry and in engineering, steam refers to vaporized water. It is a pure, invisible gas (for mist see below), which at standard atmospheric pressure has a temperature of around 100 degrees celsius, and occupies about sixteen hundred times t at 100 ° CThe degree Celsius (°C) is a unit of temperature named after the Swedish astronomer Anders Celsius ( 1701 1744), who first proposed it in 1742. The Celsius temperature scale was designed so that the freezing point of water is 0 degrees, and the boiling po and a pressure of 1/10,000 of an atmosphere.