CHEMICAL COMPOSITION AND ION-EXCHANGE PROPERTIES OF A NATROLITE FROM ZAHEDAN REGION, IRAN

摘要

This paper reports the chemical composition of a natural zeolite from Zahedanrn(Hormak) region of Iran as well as its ion-exchange behavior toward various heavy metalrncations in a batch type procedure. In this regard, the distribution coefficients(Kd ,ml/g) of Ag~+,rnPb~(+2), Cd~(+2), Cu~(+2) and Zn~(+2) cations were calculated as well as equilibrium constant (Ka) andrnGibbs free energy ?G~0(KJ.geqv~(-1)) as the thermodynamic parameters of the ion-exchangernreactions. The thermodynamic factors were computed using an excel base program from thernplotted isotherms in different temperatures (e.g. 298K and 323K). According to obtained datarnfrom different characterization techniques( e.g. chemical analysis, XRD, and TA) it wasrncleared that the investigated sample was natrolite rich-ore. The ion-exchange experiments ofrnthe zeolite were performed in order to investigating of its ability for take up of the consideredrncations from industrial wastewater streams. In the experimental condition the selectivityrnsequence was Ag~+Pb~(+2)> Cd~(+2)>Cu~(+2) > Zn~(+2) . The obtained results were showed that thernion-exchange behavior of the investigated sample toward these heavy metal cations wasn’t promising.