Activated carbon filters

Activated Carbon filters are widely used. But what are they made of? What is their real efficiency?

What is Activated Carbon?

Activated Carbon has been used over thousands of years, originally to purify water, and more recently to purify air: it traps some complex molecules, and some smells.

It is industially manufactured from different kinds of woods (kernels, barks, shells, coal, …) to keep only the carbon-based structures, and remove all oils and tars. When leaving the wood, the oils generate pores, and the residual material is very light, and it has a huge active surface in a small volume (like lung…)

When air comes in contact with activated carbon, the “complex” molecules are traped onto the surface, whilst the “simple” molecules remain untouched.

Which pollutants are fixed?

Activted carbon can fix complex molecules, so some VOCs.
The formaldehyde, which is the simplest VOC, is very badly trapped by activated carbon.
But this VOC is also the most harmfull and the most frequent…
Activated carbon cannot hold particulate matter, nor destroy viruses.

Moreover, one major drawback of this technology is that the trap is not stable: the molecules are linked onto the surface (“adsorbed”) with weak chemical links. As a consequence:

  • the surface is very quickly saturated: after few weeks, the filter has no more effect and must be replaced
  • in case of change of temperature or humidity, the carbon releases the molecules it trapped… Typically during winter, many houses become humid, and the carbon may well generate pollution.

Globally speaking, in the building industry, the professional use this technology because there is nothing else on the market; it is better than nothing, but nobody sees any real advantage in using activated carbon.

Air Serenity technology vs. Activated carbon

Air Serenity proposes a technology which is based on a similar principle as activated carbon: a material with huge surface, made of ceramics and zeolites, traps the molecules when the air goes through. But two major differences enhance the efficiency:

  • we use a blend of 8 different material, so that they capture different kind of pollutants. Formaldehyde, for instance, is well captured by the technology.
  • we “clean” the cartridge every day, with a plasma: the plasma will oxydize the molecules and dismantle them into harmelss molecules (CO2, H2O, …). This way, the efficiency remains at its top during one whole year. Also note that the quantity of CO2 produced by a cartridge during one year is similar to the quantity produced by a human being during one minute… We don’t impact the global warming!