The activated carbon is used in air filters thanks to its adsorption capacity. The activated carbon filter allows the adsorption of pollutants found in gases in the industrial atmosphere. With activated carbon filters it is possible to adsorb certain solids present in gases, leaving them free of odours and harmful compounds.
The functioning of activated carbon-based air filters is very simple. Simply put, the polluting particles in the air are adsorbed on the adhesive microporous surface of the activated carbon. Once all of the activated carbon has been exhausted and no more molecules can be adsorbed, the ambient conditions are changed in order to clean the pollutant and the activated carbon remains regenerated.
ADVANTAGES OF ACTIVATED CARBON FILTERS
In order to measure the indoor air quality (IAQ), it is assessed by the composition of gases and vapours, both organic and non-organic (ozone, carbon monoxide, radon, etc.), aerosols, currents and noise.
Filters that include an air treatment system usually have no effect on VOCs (volatile organic compounds). To remove vapours and gases, other treatments are needed, such as adsorption or chemical combination, but mainly by adsorption. Of the possible adsorbent materials, such as alumina or silica gel, activated carbon offers the additional advantage of also removing ozone.
The most abundant VOCs in public and private non-industrial indoor environments are toluene, benzene, ethylbenzene, m+p-xylenes, 1,2,4-trimethylbenzene, 1,3,5-trimethylbenzene, limonene, α-pinene, p-dichlorobenzene, trichloroethylene, tetrachloroethylene, decane, chloroform, hexanal, nonanal, acetone and 2-butoxyethanol.
It is also common to use activated carbon filters for ozone reduction. A very common use is in photocopiers. The activated carbon filter is used to reduce the emission of ozone into the indoor air of offices. It has a very high efficiency, even higher than 90%.