Abstract
In the first, Mongolian natural zeolites, whose base components were clinoptilolite, mordenite, and chabazite, were characterized in terms of element content, cation exchange capacity, and the like. Since the molar ratios of aluminum relative to silicon contained in Mongolian natural zeolites used in this study were lower than those of pure zeolites, the natural zeolite samples contained substantial amounts of impurities. The cation exchange capacity of the natural zeolite sample relatively increased with increasing aluminum content in the zeolite sample. Secondly, the batch equilibrium adsorptions of heavy metals, i.e., copper, zinc, and manganese, from model aqueous wastewater by Mongolian natural zeolites were carried. The natural zeolites could adsorb and remove the heavy metals in the aqueous solutions, and help to adjust pH to appropriate level in the aqueous solution. The precipitation of metal hydroxide by the addition of natural zeolite also removed heavy metals. The saturated adsorbed amounts of the heavy metals estimated by Langmuir equation were almost same with one another, increased with solution pH and with cation exchange capacity of the natural zeolite. The adsorption coefficient was also correlated with hydrated ionic radius of heavy metal.
