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 metal ions to assess their heavy metal ions adsorption potential. The results show that the activated carbons efficiently adsorbed the heavy metal ions 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. The significances of this study are that, the conversion of the coconut husk to activated carbons provides a solution to environmental problems associated with dumping of the waste and also provides valuable products capable of reducing the effects of heavy metals in wastewater.  Keywords: Coconut Husk, Activated Carbon, Heavy Metal, Adsorption