Treatment of metal containing wastewaters by natural zeolites

In this study, removal of heavy metals in synthetic and wastewaters was studied by using natural zeolite, clinoptilolite. The activated and non-activated zeolites used were crushed and grinded to sizes between 1.0-2.0 mm. Ion exchange studies were conducted as batch experiments for various mixing time, speed and different concentrations of Pb2+, Cd2+, Ni2+, and Zn2+. Gordes and Bigadic zeolites were used for Cd2+ and Ni2+ removal and their efficiencies were compared with that of natural zeolites from different areas. Although Cd2+ was not removed effectively by Bigadic zeolite, in applying Gordes zeolite 46% removal efficiency was achieved for 90 min of contact time in batch tests. Column studies were performed for the removal of Pb2+, Cd2+, and Zn2+ from a lead-zinc mining process raw wastewater. The clinoptilolite exhibited about 100%, 98%, and 96% removal efficiency for Pb, Zn2+, and Cd2+, respectively. The overall adsorption capacity for Bigadic clinoptilolite was around 23 mg Pb2+/g, 24 mg Zn2+/g, and 0.6 mg Cd2+/g