Removal of Cadmium Ions by Sorption from Aqueous Solutions Using Low-cost Materials

The efficiency of four low-cost sorbent materials namely peas husk, broad bean husk, medlar peel and fig leaves, for removing cadmium ions from aqueous solutions, in single systems, has been investigated in batch mode. Kinetic data and equilibrium sorption isotherms were measured. Kinetics of cadmium sorption was contact time, initial cadmium concentration and sorbent type dependent. For a given sorbent, the amount of cadmium sorbed increased with the increase of contact time and initial cadmium concentration. The kinetics of cadmium sorption were well described by a pseudo-second order rate model. Cadmium uptake of each sorbent tested was quantitatively evaluated using sorption isotherms. Results indicated that Langmuir model gave an acceptable fit to the experimental data. The broad bean husk was the most effective to remove cadmium ions with a maximum sorption capacity about 147.71 mg/g followed by peas husk (118.91 mg/g), fig leaves (103.09 mg/g), and medlar peel (98.14 mg/g), under the experimental conditions tested here.