Adsorption of Cd, Co and Zn from multi-ionic solutions onto Iranian sepiolite isotherms

Nowadays, removal of heavy-metal contaminants from industrial waste waters is one of the most important environmental polemics which necessarily requires a solution. Clays, because of their low cost and unique chemical and structural properties have been widely used to remove heavy metals from aqueous solutions. In this investigation, sepiolite mineral was obtained from a mine near Fariman Township, Khorasan, Iran. The mineral samples used in this study were powdered with sizes less than ۰.۰۵ mm (-۱). Langmuir and Freundlich isotherm models were investigated to illustrate the adsorption of heavy metals by natural and heat pre-treated sepiolites from aqueous solutions in two different pH values: ۴ and ۵. It was determined that the experimental data were more fitted to the Langmuir model (R۲≈۰.۹۹) and it was observed that cobalt ions were more adsorbed than zinc and cadmium in the order of adsorbing regularity: Co>Zn>Cd. In this study, the quantities of released Mg۲+ from the mineral structures were also investigated. In addition, changes in pH values in final solutions were investigated at the end of the experiments.

کلیدواژه ها:

heavy metals ، Environmental pollutions ، Sepiolite ، Langmuir and Freundlich