Adsorption of phenolic compounds from dilute aqueous solutions

Abstract

ABSTRACT Adsorption isotherms of four phenolic compounds have been studied onto carbon and clay treated by acid. The results indicated that the adsorption isotherms were complying with Langmuir and Freundlich models. The effect of temperature on adsorption on carbon was also studied and the results of the adsorption on active carbon showed that the adsorption increases with decreasing temperature, exothermic process, for all compounds and it is directly in accordance with Gibbs equation for equilibrium conditions. In the case of clay the increases of temperature showed that there is no a definite mechanism followed by the adsorption due the unequality between adsorption and desorption. Studies on the adsorption at different pH values on carbon showed that the adsorption increases with decreasing pH value. Adsorption on three different particle sizes of activated carbon showed that the adsorption increases with decreasing particle size