Removal of Cadmium (II) by Activated Carbon Adsorption

The adsorption of cadmium (II) from a dilute aqueous solution onto an activated carbon surface is investigated. The type and dose of activated carbon, the total concentration of cadmium (II), pH, and the presence of a chelating agent are essential parameters controlling cadmium (II) adsorption. The adsorption of cadmium (II) can be quantitatively interpreted by a surface complex formation model, according to which the surface hydroxo groups serve as the ligand and the free cadmium ions the central metal. Three surface complexes were observed. The surface stability constants vary with pH.