The ability of a type of clay to adsorb Cu(II) and Zn(II) ions from aqueous solutions was studied and optimized.
Different factors affecting adsorption were considered and studied individually. These factors include contact time, pH,
initial metal ion concentration, clay dose and temperature. Langmuir, Freundlich and Temkin isotherm models were
studied for the adsorption process. Depending on the values of correlation coefficients of the different models, it was
concluded that the adsorption of Cu(II) ions was best described by Temkin model (R
2=0.9904), where adsorption of
Zn(II) followed both Langmuir (R
2=0.9806) and Freundlich (R
2=0.9840) models. Maximum adsorption capacities
according to Langmuir isotherm were 20.08 and 17.60 mg/g for Cu(II) and Zn(II) ions, respectively. The increase of
adsorption capacity with temperature for both metal ions indicted endothermic processes