Importance of the Hydrophobic Character of Activated Carbons on the Removal of Naphthalene from the Aqueous Phase

Abstract

A commercial activated carbon was systematically modified by heat treatment at 450°C and 850°C to obtain a series of carbons with various oxygen contents, porous structures and surface functionalities. The carbons were used to investigate the role of adsorbent properties on the removal of naphthalene from aqueous solution. The results confirmed that the adsorption of naphthalene depended strongly on the pore-size distribution of the adsorbent. DTG analysis of the exhausted samples indicated that adsorption forces were stronger in carbons with pores of dimensions close to those of naphthalene. Functionalization of the carbon also influenced its overall adsorption capacity, with uptake being favoured in carbons of a basic nature. The hydrophilic character of the carbons gave rise to strong water competition due to increasing polarity in the adsorbents. This polarity created hydration clusters that reduced the accessibility and affinity of naphthalene molecules to the inner pore structure.