Adsorptive Removal of Pb(II) Ion From Aqueous Solution Using Rice Husk-Based Activated Carbon

The potential of rice husk-based activated carbon as an alternative low-cost adsorbent for the removal of Pb(II) ion from aqueous solution was investigated. Rice husk-based activated carbon was prepared via chemical activation process using NaOH followed by the carbonization process at 500 degrees C. Morphological analysis was conducted using field-emission scanning electron microscope /energy dispersive X-ray (FESEM/EDX) on three samples, i.e. raw rice husk, rice husk treated with NaOH and rice husk-based activated carbon. These three samples were also analyzed for their C, H, N, O and Si contents using CHN elemental analyzer and FESEM/EDX. The textural properties of rice husk-based activated carbon, i.e. surface area (253 m(2)/g) and pore volume (0.17 cm(2)/g), were determined by N-2 adsorption. The adsorption studies using rice husk-based activated carbon as an adsorbent to remove Pb(II) ion from aqueous solution were carried out at a fixed initial concentration of Pb(II) ion (150 ppm) with varying adsorbent dose as a function of contact time at room temperature. The concentration of Pb(II) ion was determined by atomic absorption spectrophotometer (AAS). The removal of Pb(II) ion from aqueous solution increased from 35 % to 82 % when the amount of rice husk-based activated carbon was increased from 0.05 g to 0.30 g. The equilibrium data obtained from adsorption studies was found to fit both Langmuir and Freundlich adsorption isotherms.