Copper Ion Removal by Surface Modified Activated Carbon

Heavy metal removal efficiency of activated carbon depends on the nature of the heavy metal species as well as the surface properties of the activated carbon. In this study, a commercially available activated carbon was modified by concentrated nitric acid. In addition, the modified carbon was further treated by sodium hydroxide. The modification process differentiated the chemical property of activated carbon surface rather than its physical nature. The BET measurement for the carbon's surface area showed that the modification processes had a limited impact on the carbons. Acid base titration indicated that the modification greatly changed the adsorption behavior for H + and OH -, respectively. It is found that solution pH had a significant effect on copper ion adsorption. The adsorption capacity of activated carbon under fixed pH and buffered solution was determined. It was found that the metal uptake capacity strongly depended on the surface acid base functional groups. The adsorptive behavior of these modified activated carbon is explained on the basis of their surface acidity and basicity. The data obtained from this study can be used to develop equilibrium and kinetic models for activated carbon adsorption.