Abstract
Little information is available on the interaction between an adsorbate and the surface oxides of coal-based activated carbon (AC) in non-aqueous solutions. In this study, we investigated the effects of the type of surface oxide of ACs on the adsorption of dimethoxon, a model molecule with multiple groups, from chloroform. The surface oxides and the pores and/or carbon surface of ACs were found to adsorb dimethoxon in accordance with the Langmuir isotherm, with a linear correlation between the surface oxides and adsorbed dimethoxon (R2 ≈ 0.95). The interaction between ACs and dimethoxon was further investigated by replacing the adsorbed dimethoxon with compounds containing different substituent groups. At the same amount of the compound added, the amount of dimethoxon is replaced in the following order: butanoic acid > butanol > butanone > ethyl acetate. This finding indicates that both the type of oxide and steric hindrance are important for an AC to adsorb an adsorbate or for a compound itself to replace the dimethoxon adsorbed onto ACs. The results also showed that dimethoxon adsorbed on the surface oxides may be displaced, whereas those adsorbed in the pores, carbon surface of ACs or both cannot be displaced by those compounds.