Certain contaminants accumulate on the surface of the activated charcoal in a process called adsorption. Activated charcoal is effective in removing chlorine and moderately effective in removing some heavy metals. Activated charcoal will also remove metals that are bound to organic molecules. It is important to note that charcoal is not necessarily the same as activated charcoal. Activated charcoal removes vastly more contaminants from water than does ordinary charcoal.
Home activated charcoal treatment systems are quite simple.
The activated charcoal is normally packaged in filter cartridges that are inserted into the purification device. Water needing treatment passes through the cartridge, contacting the activated charcoal on its way to the faucet. Activated charcoal filters eventually become fouled with contaminants and lose their ability to adsorb pollutants. At this time, they need to be replaced. Activated charcoal treatment systems are typically point of use installed where they typically treat water used for drinking and cooking only.