Effect of pH .Uptake experiments were performed at controlled pH and at room temperature by shaking 0.05 g of dry chitosan with 10 mL metal ion solutions of different pH values (2-9) for 4 h at 150 rpm.
The buffer solutions used for adjusting the pH of the medium were KCl/ HCl(pH1,2 and 3) which was not a buffer system ,but it was successfully used to adjust the pH in many of the pervious reports [52,53] . 0.1M HCl and 0.1M potassium hydrogen phthalate (KHPh) for Ph range (3 ,4) 0.1 M potassium hydrogen phthalate (KHPh) and 0.1 NaOH for pH range (5.0 – 7.0) .