Assessment of alkalinity on the adsorption of cadmium ion using KOH-activated carbon from Sesame stem

Abstract

The increase alkalinity on the adsorption of cd2+ using KOH-activated carbon from Sesame stem was studied. Determination of metal ion in solution shows adsorption capacities of 86.68 % for KOH-AC at saturated state. Effect of metal ion concentration shows that, Removal efficiency of Cd2+ by KOH-AC increases with increasing presence of the adsorbate due to the availability of adsorption sites on the activated carbon. Increase acidity general favors the adsorption. The effect of pH shows that the adsorption of cadmium ions increases with increasing acidity between the pH of 7.5 to 6. However, as the Cd2+ concentration becomes exceedingly high, the removal efficiency decreases. A general observation was that before equilibrium, there is rise in the removal efficiency of Cd2+ by KOH-AC with increasing contact time which is universally true for good adsorbents. Effect of metal ionic strength shows that activated carbon adsorption decrease with increase in ionic strength in any acidic medium.