Surface interaction of cadmium and zinc metal ions on Al2O3 nanoparticles in aqueous solution

摘要

ABSTRACT The adsorbent ability of Al2O3 nanoparticles (ANPs) was examined to remove Cd2+ and Zn2+ from aqueous solution. The sorption of Cd2+ and Zn2+ on ANPs as a function of pH, ionic strength (IS), humic acid (HA), contact time, foreign ions and the temperature were investigated. It was observed that physico-chemical factors (pH and ionic strength) strongly affect the sorption of Cd2+ and Zn2+ on ANPs. Comparatively, the sorption of Cd2+ and Zn2+ dominated by surface complexation of the outer sphere at low pH values (pH 8.0). The maximum sorption capacity of Cd2+ and Zn2+ on ANPs calculated from the Langmuir model was 8.40 and 9.00 mg g–1 respectively at 303?K, exhibiting higher efficiency for Zn2+ sorption than Cd2+.The thermodynamic parameters (?H0, ?S0 and ?G0) showed that the adsorption of Cd2+ and Zn2+ was endothermic and spontaneous. This investigation exhibited that ANP is an efficient, inexpensive process and thereby reasonable technology for the elimination of metal ions from the contaminated aqueous source.