Coal Ash as a Low Cost Adsorbent for the Removal of Xylenol Orange from Aqueous Solution

The removal ofxylenol orange from aqueous solution onto the coal ash was investigated at room temperature. The results show that the adsorption capacity of xylenol orange increased as the adsorption time increased and then equilibrium established after 30 min adsorption time. The results obtained revealed that the coal ash removed about 80 % of xylenol orange from the aqueous solution within 40 min. The effect of pH also studied, which showed that the adsorption of xylenol orange on the coal ash decreased as pH increased. The equilibrium adsorption isotherm data was fitted in Langmuir and Freundlich model equation and was found that the data followed both Langmuir and Freundlich isotherm models. Furthermore, we used a statistical measure (rank equation) in order to measure the strength of the relationship between the adsorption of xylenol orange onto coal ash and different adsorption time, and adsorption of different concentration of dye at equilibrium time.