Adsorption Characteristics of Pb(II) and Cd(II) Ions on Dithizone-loaded Natural Zeolite

Abstract

Adsorption characteristics of Pb(II) and Cd(II) on natural zeolite loaded with dithizone have been examined. The parameters studied includes effect of pH, contact time and initial concentrations of Pb(II) and Cd(II). Results of study show that adsorption of Pb(II) and Cd(II) reaches its maximum values at pH 5 and 6, respectively. First-order adsorption rate of Pb(II) and Cd(II) on dithizone-loaded zeolite is larger than that on original zeolite. Comparison between Pb(II) and Cd(II) shows that adsorption rate and capacity for Cd(II) is larger than that for Pb(II) but the equilibrium constant and thus adsorption energy for Cd(II) is smaller than that for Pb(II). In general, the ability of dithizone-loaded zeolite to adsorb the two metals is better than does the unmodified one.