ADSORPTION AND OPTIMIZATION STUDIES OF LEAD FROM AQUEOUS SOLUTION USING Γ-ALUMINA

Abstract

In the present study, removal of Pb(II) ions using g-Alumina was investigated. g-Alumina used in the present study was prepared by gel combustion method. The XRD revealed that the synthesized particle was in amorphous phase and the SEM image showed highly porous surface which is a characteristic property of a good adsorbent. The pore size and surface area of the g-Alumina were determined and found to be 243 m2 /g and 41 Å, respectively. The effects of pH, initial lead concentration, adsorbent dosage on the extent of adsorption and time of contact were studied. Atomic absorption spectrometer (AAS) was used to determine the concentration of lead after adsorption. The Pb(II) removal capacity of g-Alumina was found to be maximum at pH 7. From the Langmuir isotherm the maximum adsorption capacity of g-Alumina toward Pb(II) was determined (Q0 = 65.67 mg/g). Compared to other metal oxides g-Alumina showed a significantly higher adsorption capacity. Although Pb(II) adsorption occurred in the first 35 min of contact time, at least 90 min to attain equilibrium. The kinetics of adsorption can be described by first order rate equation. Statistically based experimental model such as Box–Behnken Method (BBM) was used to study the effect of variables on adsorption. Regeneration studies of the adsorbent were carried out and it was found that the adsorbent can be effectively regenerated upto 3 times with significant level of adsorption. The results suggest that g-Alumina is effective adsorbent for the removal of lead.