What is activated carbon?

Activated carbon is a material with high adsorptive capacity, composed mainly of amorphous carbon and characterised by a highly porous structure and high specific area (500 to 2500 m²/g). One gram of activated carbon has a surface area equivalent to that of a football pitch. Due to this large specific area, activated carbon can hold many molecules of other substances on its large inner surface area.

In the phenomenon of adsorption, chemical species (molecules, atoms or ions) establish a chemical-physical interaction on the separation surface between two different phases. The adsorption power of activated charcoal is assessed according to specific indices, such as the benzene index, the molasses index (indicating the ability of charcoal to adsorb high molecular weight substances), the iodine index (indicating the ability of charcoal to adsorb high molecular weight inorganic compounds) and the methylene blue index (indicating the activity of the charcoal, with particular reference to its microporosity).

Activated carbon comes in different forms:

- Granular Activated Carbon (GAC - Granular Activated Carbon): made up of particles comparable in size to sand (approx. 0.8 mm), it is used when a material with larger pores and a smaller specific surface area is required.
- Powdered Activated Carbon (PAC - Powdered Activated Carbon): made up of smaller particles, it is used when an activated carbon with smaller pores and a larger specific surface area is required.
- Extruded Activated Carbon (EAC - Extruded Activated Carbon): made up of extruded small cylinders, it is used for the treatment of gaseous emissions (e.g. in solvent recovery plants, VOCs), where low pressure drops are required.

Activated carbon can be produced from various organic substances with a high carbon content, such as wood, charcoal, peat and coconuts.

What is it for?

Activated carbon is therefore used in the filtration, purification, deodorisation and decolourisation of fluids. Under the microscope, it can be observed that activated charcoal is composed of a network of tunnels that gradually narrow, allowing pollutants in the air to be captured.

The use of activated charcoal in respiratory protective equipment is essential to control toxic gases and vapours as well as unpleasant odours, allowing users to breathe clean air during operation.

In addition to the filters of reusable masks, some models of BLS disposable masks integrate a layer of activated charcoal along with the filter material. This treatment allows the products to absorb unpleasant odours, increasing protection and comfort during use. One example is the BLS Zer0 30 C filtering face mask.