Activated Carbon Air filters: Everything you need to know(1)

- Jan 08, 2019 -

Activated carbon has special properties that allow it to remove volatile organic compounds(VOCs), odors, and other gaseous pollutants from the air. It accomplishes this in away that is different form other air purifiers like HEPA that only filter particle pollution form the air. Carbon air filters trap gas molecules on a bed of charcoal, a process that has a surprisingly colorful history. Here you will dive deep into how they work. Then you can consider if using a carbon air filter will meet your needs by examining its advantages and drawbacks.

What are activated carbon air filters?

The colorful history of carbon filtration

How do carbon air filters trap gaseous polllutants?

How to effectively use a carbon air filter?

What is activated carbon good at?

Drawbacks to using activated carbon

Should you use a carbon air filter?

Our solution

What are activated carbon air filters?

Carbon air filters are the filters most commonly sued to remove gases. They are designed to filter gases through a bed of activated carbon(also called activated charcoal ) and are usually used to combat volatile organic compounds(VOC)released from common household products. They are also often used to remove odors from the air, such as the smell of tobacco smoke. They cannot remove fine particles like mold, dust, or pollen from the air.


The colorful history of carbon filtration

Humans have been using charcoal to purify water-sometimes accicentally-for thousands of years.

First, what is charcoal or carvon? These interchgeable terms refer to the remmants of incomplete combustion. Picture the charred piece of wood that is left after a compfire. Only the readily combustible material in the wood has burned away, either because of insufficient heat or poor supply of oxygen. The black char that remains is mostly carbon. The industrial process of making charcoal accomplishes it by heating a substance in a vaccum chamber, which releases all the volatile compounds and  leave behind all the carbon. Wood is commonly used to make charcoal, but coconut shells adn coal are also used. Each substance creates a slightly different kind of charcoal.

How is carbon activated? Activated carbon is carbon that has undergone some additional processing to make it better at trapping gas molecules. First, it is injected with hot air, carbon dioxide, or steam which creates a lattice of tiny pores in the carbon, vastly increasing its surface area. This creates many more places for molecules to become trapped and makes the carbon far more effective as a filter medium. Apaper by the Ohio Environmental Protection Agency notes that a single gram of activated carbon can have hundreds of square meters of internal surface area. Most activated carbon is also treated with a chemical that enhances its ability to filter specific pollutants.       

The colorful history of using carbon filtration.   how did humans figure out that carbon can be effictive at filtering contaminants? It is likely the earliest use to remove inpurities first to use  it in a medical way, to remove odors associalted with infections. We know that sailors in the 16th through 18th centuries often stored their drinking water in barrels that had eigher been charred or smeared with carcoal on the inside to keep the water fresh on long voyages.

In World War I , gas masks utilized charcoal to filter out some of the deadly dases used against the trooops, but it was only effective against some of the toxins. The production and use of activated carbon grew dramatically only after World War II , eventually leading to the development of modern activated carbon air and water filters.