Activated carbon has been used to treat water for more than 2000 years.
It was first produced commercially in Holland during the latter part of the 19th century, used to clarify sugar and distilled spirits. Since 1930 it has been used in water treatment plants to remove taste and odour. Steam activation used in the manufacturing of activated carbon produces an extremely large surface area, Eg, 1 teaspoon > 2500 m² (26900 ft²).
The carbon surface is non-polar which results in an affinity for non-polar adsorbates such as Volatile Organic Contaminates (voc’s) that can remain in the water after the distillation phase. Adsorption is a surface phenomenon in which adsorbates are attracted to and held onto the pore surface structure of the carbon by Van der Waal’s forces.
WATER DISTILLERS AND POST CARBON TREATMENT
Water distillers can actually allow a tiny percentage of impurities; voc’s to migrate into the storage container during distillation. Voc’s including some pesticides and solvents, boil at temperatures below or very close to water (98-103°C). Distillation alone might not be enough to remove some voc’s. Water distillers use post carbon filters to remove these substances.