Selective adsorption of heavy and light metals by natural zeolites

Abstract

Recent studies have shown that zeolite can be applied through an ion-exchange process to remove metals from solutions. In this paper the potential of two zeolites to perform as sorbents for treatment of multi-metal system is investigated. Parameters such as initial metal concentration, contact time, zeolite type and affinity for heavy versus light metals are taken into consideration. All the samples were prepared and characterized by XRD, XRF and FTIR. Evaluating suitable model for the determination of binding affinity, the results showed that the pseudo second order kinetic model was adequate for such prediction. The binding affinity followed the order Co>Cu>Ca>Mg which was mainly correlated to the electronegativity of the metals. The FT-IR spectra revealed that the functional group –OH was mostly responsible for the binding of metals on the two zeolites. The zeolites studied have shown preferential binding of heavy metals and can therefore be used to mitigate the level of such pollutant in multi-metal water system