pH is an important parameter, which influences the biosorption process. With increase in pH to certain limit, the adsorption capacity increases (Fig. 1). The adsorption capacity (q) of biosorbent for Pb (II) from aqueous solution was highly dependent on pH of the solution. Maximum Pb(II) uptake capacity of pomegranate after treatment with HCl, H2SO4 and H3PO4 was 67.44, 65.80 and 68.74 mg/g, respectively at 4.5 pH. Pb(II) uptake capacity of native biomass was 67.50 mg/g. The other important reason is that at lower pH values, the cell wall ligands would be closely associated with the hydronium ions (H3O+) that restrict access to legends by metallic ions as a result of repulsive forces. This repulsion is stronger at lower pH. On increasing, pH more ligands (carrying negative charges) would be exposed with the subsequent attraction of positively charged metal ions. Similar results were reported by previous investigators. Some researchers stated that the increase in metal biosorption after pre-treating the biomass, could be due to the removal of surface impurities and exposure of latent binding sites for metal biosorption