Sorption of lead and cadmium ions from aqueous solutions using modified zeolite

The processes of lead and cadmium ions sorption by modified zeolite of Chankanai deposit were studied. Chitosan was used as a surface modifier due to its properties: nontoxicity, biodegradability and biocompatibility. The adsorption process was carried out at room temperature (295 K) and pH 7 under static conditions. The synthesized sorbent has been characterized by scanning electron microscopy (SEM), elemental analysis; the concentrations of Pb(II) and Cd(II) ions before and after adsorption were determined using atomic absorption spectroscopy (AAS). The Si/Al ratio of the zeolite was found to be 1.66, which showed the prospects of using this material as a source object. The static exchange capacity (SEC) of sorbents and the extraction degree of heavy metal ions were determined and compared. It was found that the removal of heavy metal ions increased with the increase of contact time (removal efficiency was 99.1±1.2% for Pb2+ and 83.4±1.2% for Cd2+). The adsorption capacity values of the modified zeolite for metal ions were (0.86±0.03) mg/g for Cd(II) and (0.68±0.03) mg/g for Pb(II). Chitosan-modified zeolite proved to be an effective adsorbent for removal of lead and cadmium ions from aqueous solutions.