Effect of Chemical Activation on the Adsorption of Heavy Metals Using Activated Carbons from Waste Materials

Abstract

The effect of chemical activation on the adsorption of metals ions (Cr²⁺, Cu²⁺, Ni²⁺, Pb²⁺, Fe²⁺, and Zn²⁺) using waste Nigerian based bamboo, coconut shell, and palm kernel shell was investigated. The bamboo, coconut, and palm kernel shell were carbonized at 400°C–500°C and activated at 800°C using six activating agents. Chemical activation had significant effect on the iodine number and invariably increased the micropores and macropores of the activated carbons produced from bamboo, coconut, and palm kernel shell. It also affected the adsorption of metal ions and the type of carboneous material used for activation. The highest metal ions adsorbed were obtained from bamboo activated with HNO₃. The cellulose nitrite formed during the activation of bamboo with HNO₃ combined with high pore volume and low ash content of bamboo effectively create more reaction sites for adsorption of different metal ions. This shows that waste bamboo activated with HNO₃ can effectively be used to remove metal ions from waste streams and in different metal recovery processes than activated carbon from coconut shell and palm kernel shell.