Lead (II) Adsorption on Chemically Modified Activated Carbon in Aqueous Solution

In the present study, we developed modified activated carbon (KL) for the adsorption of Pb (II). Chemically modified activated carbons (KL-A and KL-B) were prepared by nitric acid and ethylenediamine treatments, respectively. The properties (specific surface area, pore volume, mean pore diameter, acidic or basic functional groups, and pH) of KL, KL-A, and KL-B were investigated by various methods. Contact time, adsorption isotherms, and recovery of Pb (II) were evaluated. Equilibrium adsorption on KL and KL-B or KL-A was reached in about 12 h and 5 h, respectively. The experimental data was fitted to pseudo-second order model and compared with the pseudo-first order model. The optimal pH conditions for the adsorption of Pb (II) was pH = 5.1-5.5. These data were fitted to Freundlich and Langmuir models. Moreover, the adsorption mechanism of Pb (II) on KL-A was related to the ion exchange with acidic functional groups. It would be possible to recover Pb (II) by using nitric acid. The results suggest that KL-A would be useful in the adsorption of Pb (II).