Sorption of Heavy Metals from Mine Wastewater by Activated Carbons Prepared from Coconut Husk

Abstract

A study on sorption of heavy metal ions: Lead (Pb²⁺), Copper (Cu²⁺) and Cadmium (Cd²⁺) from mine wastewater by activated carbons prepared from coconut husk was conducted.  The activated carbons were prepared by carbonisation of the husk at 900 ºC pyrolysis temperature, followed by steam activation of the pyrolysis derived char. Activation was also performed at 900 ºC for various durations at steam addition rate of 0.2 mol/h/g in a Gas Fired Static Bed Pyrolysis-Activation Reactor. The derived activated carbons were contacted with mine wastewater containing heavy metals to assess their heavy metal adsorption potential. The results show that the activated carbons efficiently adsorbed the heavy metals from solution, reducing concentrations of  Pb²⁺, Cu²⁺ and Cd²⁺ from 1.56 mg/L, 1.87 mg/L and 0.69 mg/L respectively to below Ghana Environmental Protection Agency (GEPA) standards of  0.10 mg/L, 1.30 mg/L and 0.03 mg/L for Pb²⁺, Cu²⁺ and Cd²⁺ respectively.