keywords: Cissus populnea, lead, activated carbon
Activated carbon has proven to be a way out for most heavy metal ions contaminants in water. Evaluation of Pb2+ adsorption was carried out using an activated carbon from Cissus populnea stem. Adsorption was very slow at 6 – 24 hours. The removal efficiency of Pb2+ by KOH-AC and HNO3-AC increases with increasing presence of the adsorbent due to the availability of adsorption sites on the activated carbons. However, as the Pb2+ concentration becomes excessive, the removal efficiency increases. It may be noted that the efficiency of adsorption was generally high (>70 %) with both activated carbons. From the graphs, KOH-AC absorbs much of Pb2+ than HNO3-AC. The pH of KOH-AC which is closer to pH of 7 absorb the most of the Pb2+. The increase of pH increases the rate of adsorption. Acid activated shows lowest decrease at maximum amount of NaCl.