Sorption of Cu2+ and Cd2+ onto acid- and base-pretreated granular activated carbon and activated carbon fiber samples

We have investigated the enhanced sorption of Cu2+ and Cd2+ on a granular activated carbon (GAC) and an activated carbon fiber (ACF) after acidic and basic treatments. The commercial GAC and ACF were pretreated with 1.0 M HNO3 and KOH, respectively, and their pore structures and surface properties were evaluated using nitrogen adsorption, pH titration, elemental analysis, and pH of the point of zero charge measurements. The sorption capacities of the acid- and base-pretreated GAC and ACF for Cu2+ and Cd2+ were enhanced as a result of an increase of the acidic-oxygenated groups and number of the micropores, respectively.