Removal of lead(II) ions from aqueous solutions by adsorption onto pine cone activated carbon

Activated carbon prepared from the cones of the European Black pine was used as adsorbent for the removal of lead(II) ions from aqueous solutions. The effect of pH, initial concentration of lead(II) ions, contact time, and adsorbent dosage on the adsorption was studied in a batch process mode. Equilibrium data were analyzed by the Langmuir, Freundlich and Temkin isotherm model. Langmuir isotherm provided the best fit to the equilibrium data with maximum adsorption capacity of 27.53 mg/g. The kinetic data were found to follow closely the pseudo-second-order model. The microstructures of the activated carbon before and after adsorption of lead(II) ions were observed by scanning electron microscope. Textural analysis was employed in order to determine specific surface area and pore size distribution of the prepared activated carbon. Surface structure was characterized by using Fourier transform infrared spectroscopy and Boehm titration.

Research Highlights
► Pine cones might be used as possible substitute in the production of activated carbon.
► The synthesized carbon exhibited significant adsorption capacity for lead(II) ions.
► Lead(II) adsorption was strongly affected by solution pH.
► Adsorption fit well with the Langmuir isotherm.