How Activated Carbon Filters Work and How to Make One

Activated carbon filters are designed to filter air and gases and remove harmful substances and unpleasant smells from them. They are made of activated carbon powder or granules that have been treated to be porous – that is, they have a lot of tiny holes where dirty air may pass through. These minute spaces allow the carbon to attract and “adsorb” impurities such as contaminants, chemicals, and allergens. When these pollutants are adsorbed, they stick on the surfaces of the carbon molecules, and they keep on sticking to them until the filter has been saturated. A saturated air filter is one with holes that have been filled up with these dirty particles.


Activated carbon air filters have different levels of efficiency. Some can only eliminate odors and large airborne particles, while others can deal with things that are as small as pollen, pet hair, dust, and mold spores. Most of them can handle common household chemical fumes and volatile organic compounds that float in indoor space. To make them work effectively, the air in the space must circulate well and the filters replaced whenever they have exceeded their maximum capacity.


How to Make an Activated Carbon Filter


Plain carbon has the ability to adsorb impurities. Activating carbon means increasing its surface area to provide more room for pollutants to adhere to. This is done by both chemical and physical processes.

To make activated carbon, the first thing you need is charcoal. Burning dry wood or plant fiber at 1,000 – 1,300 degrees Fahrenheit may help you produce it. The goal is to obtain carbon out of the substance you burned.

Grind the charcoal with a mortar and pestle until it turns into black powder. Breaking up the carbon this way enables it to be in contact with air molecules.

After physically treating the carbon, chemical treatment follows. Get a 25% solution of calcium chloride or bleach – you can make it on your own by mixing 1 part of the chemical with 3 parts of pure water. Mix this solution with the charcoal powder until they form a thick paste. Be careful though; the mixture will heat up so you must wear thick gloves to protect your hands. If you dislike working with chemicals, lemon juice may also work.

When you’ve mixed them up thoroughly, spread it until it dries. Let this sit for a day. Afterwards, put the charcoal on top of a filter and rinse it with clean water to remove debris. Let this dry again. Bake the paste at 230 degrees Fahrenheit for at least half an hour. When this is done, your carbon is already activated. To use it for filtering air, you simply put the charcoal into a tiny box and put that inside your air filter. You may also put the charcoal into small bowls and put them in places that frequently accumulate bad smells, such as in the toilet or kitchen.

Where to Buy Activated Carbon Air Filter

Activated air carbon filters are available from hardware stores that sell air filters and air purifiers. You can buy them online, too. Although making your own air filter may be fun, it is tough work. Consider purchasing one instead to get guaranteed air purification.