Purification of natural zeolite-clinoptilolite for medical application-Extraction of lead

A series of experiments of the leaching of lead and other cations from three samples of natural zeolite–clinoptilolite, (Sample 1–deposit Zlatokop, Vranjska Banja, Serbia and Montenegro; Sample 2–deposit Bala Mare, Romania; Sample 3–Igros near Brus, Serbia and Montenegro) using EDTA was conducted. The results of the experiments showed that the extraction efficiencies from the examined samples were different. If a suficiently large amount of EDTA was applied, most of the lead was extracted only from Sample 1–deposit Zlatokop. Similar effects were obtained for the leaching of iron. The differences in the extraction efficiencies may be due to the difference of the of lead and iron species present in the zeolite crystals. The effects of EDTAconcentration and solid/liquid ratio on the extraction of lead, iron and aluminum were studied