Development of method for the preconcentration of cadmium and lead by solid phase extraction, investigation of adsorption kinetics and termodynamics

In this study, the method is developed for the preconcentration of Cd(II) and Pb(II) ions by using columns containing Amberlyst 15 copolymer and determined by atomic absorption spectrometry. The effect of the factors such as pH, the type and concentration of elution solution, the flow rate and the volume of the sample solution on the preconcentration efficiency has been investigated. At optimum conditions (pH: 4 and flow rate: 1 mL/min) determined experimentally, the recovery of Cd(II) and Pb(II) were found as to be (104 ± 1)% and (102 ± 2)% respectively, by using 5 mL elution solution of 2 mol/L HNO3. In order to investigate the applicability of the method to real samples, the effect of some elements such as Fe, Ni, Co, Mn, Cr, Na, K, Ca and Mg on the recovery has been investigated. The proposed method has been applied to the real water samples and Cd(II) and Pb(II) were determined with the relative errors < 5,0 %. The analytical limit of detection (LOD) and analytical limit of quantification (LOQ) for Cd(II) and Pb(II) have also been determined as to be 0,23 ?g/L and 0,75 ?g/L for Cd(II), 0,13 ?g/L and 0,42 ?g/L for Pb(II) respectively. Moreover, the adsorption capacity of Amberlyst 15 for Cd(II) and Pb(II) ions were determined by using batch method and found as 152 mg/g and 154 mg/g at 298 K respectively. The adsorption kinetics was studied and kinetic order was found as pseudo second order for two ions. After termodynamic studies, ?Gº, ?Hº ve ?Sº values have also been determined and the adsorption reaction is showen to be exothermic for Cd(II) and Pb(II).