Abstract:Natural zeolite was used as adsorbent to remove heavy metal ions. Macroscopic and microscopic characteristics of zeolite materials were characterized. Adsorption effect of single heavy metal and multiple heavy metals were investigated, and adsorption kinetics and adsorption isotherm characteristics were studied. The results show that heavy metals in solution could be successfully adsorbed by natural zeolite. The natural zeolite contains heulandite, cristobalite, quartz and kaolinite, and particles appear irregular shape with particle sizes of 0.189-129.3 μm, and their surfaces consist of some flake-like minerals, which main components are alumina-silicate minerals. The Zeta potential analysis shows that negative surface makes natural zeolite could efficiently adsorb heavy metals in solutions and sequence of adsorption ability is Pb>Cu>Cd>Zn. Higher solution pH value can promote adsorption process of heavy metals. The fast adsorption process of heavy metals on natural zeolite could complete within 50 min. The quasi-second-order kinetics is more suitable for fitting adsorption process of heavy metals on natural zeolites. Adsorption process of Cd is suitable to Langmuir adsorption isotherm and adsorption process of Pb, Cu and Zn is suitable to Freundlich adsorption isotherm. Under competitive adsorption system, competitive adsorption advantages of Pb and Cu are mainly reflected in higher natural zeolite dosage and the order of adsorption advantage is Pb>Cu>Cd > Zn.