Removal of heavy metals from aqueous solutions by adsorption using single and mixed pillared clays

This work concerns the application of single and mixed pillared clays in adsorption of inorganic pollutant in the water: the cadmium, the cobalt, and the copper. Adsorption experiments were conducted under various conditions, i.e., pH, contact time, initial concentration, and temperature. A comparison of the adsorption of the three metals onto pillared clays and natural clays suggested that pillared clays had higher adsorption affinity for metals than the unpillared clays. The experimental results indicated that the pillared clays rich on cerium show better properties on Cd2+, Co2+, and Cu2+ adsorption than those without cerium, which made them the promising recycling metals adsorbents. The equilibrium isotherm data were analyzed using the Langmuir and Freundlich isotherm equations. In all cases, the adsorption process fitted the second-order kinetics well, and the isotherm equation due to Langmuir showed good fits with the experimental data.