An air or gas treatment system comprising a structured adsorbent or catalyst in the first pipe

An air or gas treatment system, comprising:

• at least a vessel comprising at least a first aperture configured to receive and to release gas and at least a second aperture configured to release and to receive gas, the first and second apertures defining a passage between them, the passage having an inner cross-sectional area SV,
• an adsorbent or catalyst placed in the passage, the adsorbent or catalyst being configured to adsorb or trap at least partially at least one component of gas received by the adsorbent or catalyst such that gas released from the adsorbent or catalyst has an outgoing composition different from an incoming composition of gas received by the adsorbent or catalyst,
• at least a first pipe fluidically connected to the first aperture of the vessel, the first pipe having an inner cross-sectional area SP different from the inner cross-sectional area SV of the vessel, and
• a structured adsorbent or catalyst in the first pipe, the structured adsorbent or catalyst being configured to adsorb or trap at least partially at least one component of gas received by the structured adsorbent or catalyst such that, gas released from the structured adsorbent or catalyst has an outgoing composition different from an incoming composition of gas received by the structured adsorbent or catalyst.