Activated carbon filters are one of the indispensable components of air purifiers.
Their primary goal remains to intercept molecules that are considered harmful to the environment and are present in the indoor air.
These molecules consist of volatile organic substances, which are responsible for the unpleasant odours in the ambient air.
Activated carbon remains in itself a material with a porous structure and a carbon-containing material.
It can be obtained from any organic substance of plant origin as long as it has a high carbon content.
They can be made of .B. bark, coconut shells or, more generally, wood. If its surface is activated by a chemical or physical process, it can then reach a surface area of 400 m2.g-1 to 2,000 m2.g-1.
Under these circumstances, activated carbon is able to hold back molecules from liquids and gases, but their effect on the latter depends primarily on the humidity of the room air.
Depending on the activation process and the raw material, the pore diameter may vary.
When the activated carbon is extracted from coconut shells, the pores have a pore size of less than 2 nm, compared to an average pore size of 50 nm for wood-based activated carbon. Therefore, pores between 1 and 2 nm will be more effective for air purification.
What is an Activated Carbon Filter? What They Are & How They Work
Why use an activated carbon filter?
The use of activated carbon filters (such as Levoit air purifiers) offers many advantages to getting rid of the many pollutant particles in the room air.
Some of these molecules can be harmful to your health, especially if you are prone to certain respiratory diseases.
By using an air purification system that uses activated carbon filters, the various impurities are intercepted from the finest to the largest:
- Neutralization of general dust.
- Floating lint.
- Mold spores.
- Animal hair.
- A wide range of chemicals used in daily household, as well as benzene and VOCs.
Activated carbon is an indispensable material for removing various pollutants from your home or apartment.
In combination with a ventilation system, many impurities invisible to the naked eye are neutralized, resulting in healthier air.
Functional principle of an activated carbon filter
The use of an activated carbon filter is based on the principle of physisorption, i.e. adsorption. When the gases of the ambient air come into contact with the activated carbon, they settle directly in the pores of the coal.
This purifies the air leaking from the filter from the adsorbed gases.
Amalgamation is often performed between absorption and adsorption. The difference is that during the absorption process, the molecules that make up the liquid or gas are directly connected to a solid and add up to a total volume. Conversely, the adsorption process only takes into account the surface of the solid.
Here you will find two separate activated carbon filters. The first, the granular activated carbon filter or GAC (Granular Activated Carbon), is made of granules with a diameter of up to 3 MM.
It is a filter with excellent durability that can be combined with other chemicals such as zeolite to make it effective against certain gases such as formaldehyde.
Finally, the activated carbon fiber filter has small pore sizes between 10 microns and 50 microns. It is handier than the first filter and its adsorption capacity is more efficient.
Efficiency or efficiency factors of activated carbon filters
The effectiveness of the activated carbon filter depends on many parameters:
First of all, we need to look at the materials used in the production of coal. As seen before, the pores are smaller when made from coconut shells.
The density of the grains and their size is another factor influencing them.
The exchange area with the airflow and coal must also be taken into account.
The effectiveness of the seal between the duct and the filter is also crucial.
With high humidity in the room, the efficiency of the activated carbon filter is significantly reduced, as the water molecules are first absorbed.
The combined use of the activated carbon filter with other filters protects it from certain particle deposits.
The higher the airspeed in the filter, the less effective it is, as the activated carbon does not have enough time to clean the air.
Depending on the pollutants encountered, the overload speed is not the same, which requires a more complex calculation to estimate durability.