Identification of New Sorbent Materials for Cadmium Removal from Aqueous Solutions

This study compares the abilities of four low-cost materials: eucalyptus bark, maize leaves, grape bunch and banana peel to remove cadmium from synthetic aqueous solutions. Kinetic data and equilibrium sorption isotherms were measured in batch conditions. Kinetics of cadmium sorption was contact time, initial cadmium concentration and sorbent type dependent. The results also showed that the kinetics of cadmium sorption were described by a pseudo-second order rate model. The cadmium uptake of these low-cost materials was quantitatively evaluated using sorption isotherms. Results indicated that the Langmuir model gave a better/an acceptable fit to the experimental data than the Freundlich equation within the concentration range studied. A high cadmium sorption was observed by these materials. The eucalyptus bark was the most effective to remove cadmium ions with a maximum sorption capacity about 99.50 mg/g followed by grape bunch (75.59 mg/g), banana peel (69.44 mg/g) and maize leaves (57.84 mg/g).