How does Activated Carbon work?

Activated carbon can be manufactured out of many different types of organic materials. Coconut shells are a common material, coal is another. In the case of CPP, the starting material is a polymer. The polymer goes through two process steps. First it is carbonized and then it is activated. Both the carbonation and the activation take place under high temperatures and aim to create a high porosity. And it is in these pores that gas molecules are captured. The phenomenon is called adsorption. More about this below.

Gases tend to be dispersed in air without the need for air to move. A good example is when we smell that someone, a little further away, starts peeling an orange. Gas molecules move through so-called Brownian motions. There are small collisions between the molecules that gradually spread in the room and strive to create an even concentration.

Molecules are naturally adsorbed to surfaces through van der Waal's forces. Everyone who has been to a smoky restaurant and then, when they come home, felt the stench of the clothes has experience of just this.

When the gas molecules meet an activated carbon, the gas molecules are adsorbed on the surface of the carbon bead. Since activated carbon has an enormously large inner surface (usually measured in m²/gram of activated carbon and can amount to over 1000 m²/g), it has a very large adsorption capacity. And through the Brownian motions, the gas molecules move further and further into the pores where they finally get stuck. The narrower the pore in relation to the size of the molecule, the stronger the bond because the van der Waals forces act from several directions.