Effect of texture and surface chemistry on adsorptive capacities of activated carbons for phenolic compounds removal

Three microporous commercial activated carbons (AC) were used for the adsorption of phenol and salicylic acid from aqueous solution. Equilibrium adsorption data were obtained by the bottle-point technique. Long periods of time were needed to reach the equilibrium between the active carbon and the aqueous solution. Adsorptive capacities obtained from the isotherms were calculated following the ASTM 3860 procedure. Carbons with a high oxygen content were found to present lower adsorptive capacities for both phenol and salicylic acid. Column tests were also used for the uptake of phenol and salicylic acid, and adsorptive capacities were calculated from the breakthrough curves. Adsorptive capacities calculated from the breakthrough curves were found to be significantly lower than those evaluated from the equilibrium isotherms.