The researchers selected a plant activated carbon. The activation is done through a combustion, followed by a heat shock in the presence of water vapor, making it porous. These pores attract and retain liquid or gas. Activation thus increases the power of the carbon adsorbent. Is defined as the adsorption of gas fixing property or other substances. Protective layer and essential to the life of the hive, Propolis gives off a sweet smell associated with aromatic resins it contains.