Adsorbent screening for airborne BTEX analysis and removal

Adsorption is a commonly used technique for removal and analysis of gaseous pollutants due to its cost efficiency at low concentrations. In this work, single and competitive BTEX adsorptions were studied on three non-porous, mesoporous and microporous commercial adsorbents, namely Carbopack® B, SBA-16 and HKUST-1, respectively. For all these materials, C₈ aromatics were preferentially adsorbed, preventing in some cases the adsorption of the most volatile species, i.e. benzene and toluene. This behavior indicates that the competition phenomenon is closely related to the strength of adsorbate-adsorbent interactions. Activation energies for the desorption process were determined to be 33.8 and 33.7 and 35.9 kJ/mol for Carbopack® B, SBA-16 and HKUST-1, respectively, demonstrating that stronger interactions are present in microporous materials. Among the investigated adsorbents, SBA-16 seems to be the best candidate for air treatment and analysis since it exhibited high adsorption capacity, moderate hydrophobicity, minimal roll-up and low activation energy for the desorption. The experimental results obtained illustrate the complexity of multicomponent adsorption process on materials with different porosity and surface chemistry.