Adsorption of toluene and acetone vapors on microwave-prepared activated carbon from agricultural residues: isotherms, kinetics, and thermodynamics studies

Activated carbons produced with agricultural residues have attracted substantial attention in recent years. However, much work remains to be done. The current study determined the adsorption isotherms for toluene and acetone vapors for pinewood chip-derived activated carbon. The effects on the physical properties, such as the porous structures of the adsorbents, were also investigated using scanning electron microscopy (SEM). The results indicate that the activated carbon is a mainly microporous structure with a micropore volume of 0.701 cc/g (75.1 % of the total pore volume). The adsorption capacities of toluene and acetone can be as high as 0.71 and 0.57 g/g at room temperature, respectively. The adsorption isotherms for toluene and acetone vapors were obtained from 25 to 45 A degrees C, with relative pressures between 0.01 and 0.9. As the temperature increased, the adsorption capacity decreased. This behavior indicates that the adsorption process is physical adsorption. The fitted isotherms using the Dubinin-Radushkevich adsorption models exhibited low mean total relative errors. The fitted isotherms obtained using the Dubinin-Radushkevich adsorption models had mean total relative errors of 3.3 and 4.1 % for the adsorption of toluene and acetone, respectively, at temperatures ranging from 25 to 45 A degrees C. The results of this study may be highly significant because they provide a more accurate prediction of the adsorption capacities of the adsorbents, thus improving the design of adsorption systems.