Performance of different carbonaceous materials for emerging pollutants adsorption

• Micropollutants are removed from waters by adsorption on carbonaceous materials.
• Adsorbents tested: activated carbons, carbon nanofibers and nanotubes, and graphites.
• Equilibrium modeling and thermodynamic analysis.
• Morphology and physic-chemistry of pollutants determine their adsorption parameters.

The adsorption of three representative emerging pollutants over different kinds of carbonaceous adsorbents has been studied in this work. The adsorbates were nalidixic acid (NAL, representative of a pharmaceutical), 1,8-dichlorooctane (DCO, a chloroparaffin) and methyl-phenoxy-ethanol (MPET, a surfactant). Activated carbons, carbon nanofibers, carbon nanotubes and high surface area graphites have been tested as adsorbents. Adsorption isotherms, carried out in a batch system, were fitted using both a Langmuir and a Freundlich model. It was shown that the capacity of adsorption follows the order DCO ≫ NAL > MPET for all the adsorbents, and among the adsorbents, the external morphology (surface area and mesoporous volume) is the key parameter. The results from thermodynamic analysis show, however, that both morphological and chemical properties of both adsorbates and adsorbents influenced their behavior.