During usage, activated carbons adsorb different organic compounds and/or minerals and finally lose all or part of their adsorption capacity, even if the process in which they are used includes desorption. They must then be replaced. In the case of activated carbon in granular form, reactivation may be carried out in order to restore the used product's initial properties, thereby allowing it to be used again.

The reactivation process varies depending on the type of carbon involved, its application and its intended application. Activated carbon is guaranteed for iodine number and granulometry. GAC may be reactivated several times if the process is carried out under controlled conditions.

The reactivation cycle consists of three steps:

1 - Separation of filtering media:

Carbon used in water treatment often displays a concentration of sand as high as 10%. The sand is separated from the carbon in the factory using densimetry after the filtering medium has been dried.

2 - Reduction of mineral matrix:

Reduction of the mineral matrix content of the activated carbon is achieved by washing, first with high concentrations of acids and then with progressively weaker concentrations until the final wash with pure water.

3 - Elimination of organic materials and reactivation:

The most commonly employed treatment is thermal treatment similar to activation. Distillation and high-temperature oxidation of organic matter are carried out at the same time, restoring the carbon to its initial structure. Reactivation of carbon is even more successful if beforehand it has been cleaned of any mineral matter obstructing its pores.