Grain size and pH effects on adsorption of Zn on one type of natural zeolite

Mining related industrial wastes are primary sources of heavy metal contamination in soils and groundwater. Limitation of such waste in drinking water needs requirement for safeguard human health and environment. Zinc, one of the most important pollutants is difficult to remove from wastewater. This paper investigates Zn adsorption characteristics of one natural zeolite found in the around of Mianeh city, in west parts of Iran. For this purpose, after preparing the zeolite sample, A volume of 100 cm3 of ZnCl2 with various amount of the sample was placed in an erlenmayer flask. an‎d agitated. Then metal concentration in the supernatant was determined by atomic absorption. The results showed that factors affecting adsorption characteristics of the zeolite are competition of the H+ ions with Zn++ ions, ion exchange, and participation of zinc hydroxyl species in the adsorption. Also, decrease in grain size, increased adsorption capacity of the zeolite about 23%.