Activated Carbon Air Filters

Charcoal has been used as a water and air purifier since a very long time. It has certain properties, which help to remove the chemical impurities. Activated carbon is a piece of charcoal that has been processed, so as to have a very large surface area. The surface area of 5 grams of activated carbon equals the size of a football field. Activation of carbon gives it a slightly electropositive charge, so as to attract the negatively charged impurities.

How is Activated Carbon Manufactured?
Activated carbon is manufactured from nutshells, coconut husks, hardwood and other substances that have a high carbon content. These substances are then burned at a very high temperature, in the presence of steam and in the absence of oxygen. This process aims at removing all non-carbon contents from the source material. The residue resulting from the process has very high porosity and thus, a very large surface area.

How does the Activated Carbon Air Filter Work?
The positively charged active carbon attracts negatively charged impurities. This process is called as 'adsorption'. The gas molecules of chemicals and other impurities get stuck in the numerous tiny pores on the surface area of the activated carbon pad, present in the filter. The amount of impurities attracted by the filter would be in proportion with the amount of carbon and its thickness. The large surface area allows more pollutants to come in the contact of the filter and hence cleans large volumes of air. A small piece of activated carbon in the carbon air filter is capable of removing impurities from the whole house.

Activated carbon air filters are better than other odor removing mechanisms, like sprays and fresheners. While they only fool our senses into believing that there is no odor, the odor actually still exists. Whereas carbon filters practically eliminate the odor by capturing the impurities or gas molecules responsible for it.

Activated carbon is not used as the sole filtering mechanism. Most air filters use activated carbon as a secondary filter in their systems. The different types of filters that use activated carbon are as follows:

• Activated Carbon Pleated Panel Filters: These filters eliminate particulate pollutants, gases and odors.
• Chemically Enhanced Carbon Pleated Panel Filters: Apart from gases and odors, they also remove the volatile organic compounds (VOC's).
• High Efficiency Gas Adsorption (HEGA) Filters: They are capable of effectively removing a wide range of vapors and odors.
• Carbon Loaded Rigid-Box Filters: They are capable of removing odors effectively even with a small concentration of active carbon.
• High Mass Zero Dust (HMZD) Panels: They are suitable for the areas, which demand high quality of clean air like airports, museums, water-treatment plants, semi conductor manufacturing units, etc.
• Carbon V-Bank Filters: They offer high contamination removal and are disposable as well. Various mediums like cloth, pad, etc. can be used for filtration, but the selection of media depends upon the type of impurities to be removed.
• Military Carbon Cloth Media: It uses cloth as a media to capture the allergy pollutants trapped by the active carbon.

The problem with activated carbon air filters is that the pad or the medium needs periodic replacement as it gets clogged. Otherwise, they are cheap, easy to maintain and effective for removing all types of odors, dust and other pollutants.