Filtration device for air purification appliance

A filtration device for an air purification appliance comprising a first filtering cartridge structure containing a traditional absorbent or adsorbent material, the traditional absorbent or adsorbent material being selected from among activated carbon or zeolite, wherein the filtration device comprises a second separate filtering cartridge structure holding in place a filtering medium comprising a nanoporous matrix of metal oxides, said matrix containing a specific adsorbent material that is porous and functionalized with at least one probe molecule configured to trap chemical contaminants of an aldehyde type, wherein a specific surface area of the specific adsorbent material is between 400 and 1200 m2/g, wherein the at least one probe molecule is added to the specific adsorbent material in situ to functionalize the specific adsorbent material, and wherein the specific adsorbent material is in the form of granules.