SURFACE MODIFICATION OF OLIVE STONE WASTE FOR ENHANCED SORPTION PROPERTIES OF CADMIUM AND LEAD IONS

This paper reports the synthesis and characterization of an efficient anionic olive stone waste-based material as new ion-exchanger adsorbent. The olive stone waste was subjected to an alkaline pretreatment in order to enhance their reactivity towards maleic anhydride. The maleate-derived material MOS was characterized by FTIR, C-13 NMR, TGA and DSC. The resulting sodium form of material NaMOS was subjected to batch experiments in order to evaluate its cadmium and lead removal efficiency. Adsorption experimental data showed a uniform and rapid process. Both Langmuir and Freundlich isotherm models were found to fit adequately the equilibrium isotherm data. The sorption capacities reached 240.96 mg Cd g(-1) and 127.38 mg Pb g(-1). The thermodynamic parameters showed that the process was exothermic and the adsorption occurred spontaneously. The desorption experiments show a quantitative recovery of the metal ions from NaMOS material.