Cadmium ions adsorption from aqueous solutions by Bentonite clay, fixed bed column

Cadmium metal is discharged to the water from different industries. It can cause serious troubles for human being and aquatic ecosystems. The adsorption technique applied in this study to remove cadmium from simulated aqueous solutions onto bentonite clay by various experiments. Fixed bed system was implemented to verify the Impact of pH, initial cadmium concentration, adsorbent bed height, flow rates and the treatment time on cadmium ions removal. The results show up that when the pH of the aqueous solution was lowered, the cadmium removal efficiency increased. The cadmium removal efficiency decreased due to the increased initial cadmium concentration. Experiments have shown that increasing the contact time and the adsorbent medium in the column lead to more removal efficiency. Removal efficiency increased when the flow rate decreased. The best removal efficacy was (80%) when the pH of (3), initials cadmium concentration (3mg/l), height of the adsorbent bed (50 cm), flow rates (10 ml/min.) and the treatment time of (120 min.). Finally, the bentonite clay can be used for cadmium ions removal instead of more expensive adsorbents, because of its low cost, availability and perfect adsorption property.. (paper)