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

F T Ademiluyi,E O David-West

doi:10.5402/2012/674209

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.

Highlights

The increased concern by environmentalist and government on the effect of heavy metals and n attempt to protect public health gave rise to a lot of research in the development of advance technology to remove heavy metals from water and waste waters
The highest iodine number obtained for coconut shell was obtained when H2SO4 was used as activating agents while highest iodine number for palm kernel was obtained when HCl was used as activating agent
The amount of iron II ions adsorbed by carbons from bamboo, coconut, and palm kernel activated with HNO3, H2SO4, and HCL was significantly higher than carbons activated with ZnCl2, NaOH and H3PO4

Summary

Introduction

The increased concern by environmentalist and government on the effect of heavy metals and n attempt to protect public health gave rise to a lot of research in the development of advance technology to remove heavy metals from water and waste waters. Several works on activation of carboneous materials showed that the specific surface area, pore structure, and surface chemical functional groups of porous carbon determined their applications. Yan and Viraraghavan [2] used different chemicals to study the effect of pretreatment of Mucor rouxii biomass on bioadsorption of Pb2+, Cd2+, Ni2+, and Zn2+. Pretreatment with detergent and alkali chemicals such as NaOH, Na2CO3, and NaHCO3 were found to improve or maintain the bioadsorption capacity in comparison with live M. rouxii biomass. Effect of chemical activation using KOH and K2CO3 on activated carbon from Lignin from the work of Xiao et al [4] showed that the activated carbon from Lignin activated using K2CO3 gave higher iodine number, surface area, and higher methylene blue number than those activated using KOH

Objectives

Methods

Results

Conclusion