Abstract: The present invention discloses an air filter cartridge for use in an air-purifying device for removing formaldehyde (methane, HCHO) and other aldehyde-like VOCs (Volatile Organic Compounds), and in certain embodiments amine-like VOCs, from indoor air. The air filter cartridge is made up of a casing containing a plurality of filament-like elements as a support and a mixture of one or more natural polyphenols and a catalyst integrated in said support as a powder, forming a sponge-like mesh. The air filter acts as an absorption filter, the sponge-like mesh reacting irreversibly with the aldehyde-like VOCs present in the air, generating a polymer in the form of a polyphenol-aldehyde resin inside the air filter. Due to this irreversible reaction, the air filter is capable of capturing formaldehyde, as well as other aldehyde-like VOCs that are less reactive than formaldehyde, amine-like VOCs and ammonia.

Abstract: A filter and a method for removing aldehyde-type VOCs from indoor air are disclosed. The filter includes a casing acting as a container. The container comprises two air-permeable opposite walls through which a volume of said indoor air flows and houses one or more natural polyphenols and a catalytic agent. The filter acts as an absorption filter, reacting irreversibly with the aldehyde-type VOCs of the indoor air. The natural polyphenols are powdered polyphenols selected from resveratrol (3,4?,5-trihydroxystilbene), resorcinol (1,3-benzenediol), pyrogallol (1,2,3-benzenetriol), phloroglucinol (1,3,5-benzenetriol) and hydroquinone (1,4-benzenediol), or combinations thereof. The catalytic agent is a solid sulfonic acid. A mixture of the natural polyphenols and said catalytic agent are present, in the container, as compacted block elements. An air-purifying/decontaminating device comprising the filter is also disclosed.