Adsorptive characteristics of cadmium and lead on the goethite-coated sandsurface

This study was conducted to develop a heating process for coating crystalli ne goethite on the sand surface to utilize the adsorbent properties of the coating. Goethite-coated sand was investigated for adsorbing cadmium and le ad ions from water by batch and column experiments. Chemical analysis (ener gy dispersive analysis of X-ray, EDAX) was used for characterizing the cadm ium and lead adsorption sites on goethite-coated sand. From the results of the batch experiments, the cadmium and lead ions could be adsorbed effectiv ely on the goethite-coated sand. Maximum adsorption capacity values for cad mium and lead were 319, 704 mug-Cd/g-sand and 702, 124 mug-Pb/g-sand at pH = 5.0, pH = 6.0, respectively. The interaction between cadmium, lead ions a nd goethite on sand surface was primarily to cause the chemical bonding. Re sults from column experiments indicated that the cadmium and lead ions coul d be removed higher than 95% before 110, 130 and 66, 85 numbers of pore vol ume of influent were treated at pH = 5.0 and pH = 6.0, respectively.