Agricultural waste biomass converted to activated carbon as a material for gold processing

Waste biomass in the form of coconut shells was pyrolyzed and activated with steam to produce activated carbons, which were then assessed for their potential for use in the processing of gold. Activated carbons with different amounts of carbon burn-off were prepared by steam activation of carbonized coconut shells. Carbonization of the shells was performed at a pyrolysis temperature of 600?°C and the resulting chars were activated in steam at a gasification temperature of 900?°C and various durations of activation time. Textural characteristics of the derived activated carbons were determined and their effects on gold adsorption from an acidified gold chloride solution were studied. The surface area and porosity of the activated carbons increased with activation time up to 59 wt?% carbon burn-off. A further increase in the burn-off resulted in the loss of structural walls between pores and consequently, a decline in the surface area and porosity of the activated carbons. The gold adsorption capacity and rate of gold adsorption from the gold chloride solution onto the activated carbons were found to increase significantly with the total pore and micropore volumes of the activated carbons.