Retention of air-phase VOCs in cup-stacked carbon nanostructures

Abstract

Adsorption has been employed in the treatment (or simply concentration) of VOCs for environmental or industrial applications using several kinds of adsorbents. Due to its porous structure, activated carbon is often used for this purpose. Its good affinity to organic compounds, low cost and high availability are other reasons for its popularity. The present work focuses on evaluating the performance in the adsorption/desorption cycles of two volatile organic compounds (phenol and toluene) in cup-stacked nanostructures (CNT) using a well-known graphitized carbon black (Carbotrap) as reference. The sampling and analysis stage included a standardized method by U.S. Environmental Protection Agency (Method TO-17). VOCs were flushed through two adsorbents (Carbotrap and the composite: Carbotrap + CNT); then samples were thermally extracted for analysis via gas chromatography/mass spectrometry (GC/MS). The CNT recovered a larger mass of sorbate per adsorbent mass, which resulted in an evident superiority in CNT’s performance when compared to Carbotrap. Also, interactions between each VOC and each sorbent material were not different, either during adsorption or desorption.