Adsorption of Azo Dye on Activated Carbon Prepared from Waste Wood: 2. Equilibrium

Abstract

The present study was designed to investigate the effect of activation temperature on carbon prepared from the wood of Salvadora oleoides. The samples were characterized. Activation at 800 ºC is higher due to the decrease in polarity of the carbon surface, resulted from the decomposition of some of the acidic oxygen surface functionalities. Increase in adsorption rate was observed for higher temperature activated sample due to the increase in the surface area and opening of the blind pores and the increase in pore volume. Lower rate of dye adsorption on sample activated at 400 ºC may be due to the fact that polar functional groups situated at the pore opening have adsorbed water strongly through hydrogen bonds that in turn has resulted in the pores constriction or blockage. Freundlich, Langmuir, DR isotherm, and distribution coefficient models were used to compare the efficiency of the carbon activated at different temperature (400, 800 ºC). The data generated from all isotherms, show that 800 ºC activated sample has greater dye adsorption capacity.