THERMODYNAMICS AND MECHANISMS STUDIES FOR ADSORPTION OF PHENOLS FROM AQUEOUS-SOLUTION ONTO ACTIVATED CARBON

The thermodynamics and mechanisms of the processes of adsorption of ph enol and o-cresol from aqueous solution onto activated carbon have bee n studied. The adsorption isotherms have been measured at different te mperatures. The results show that the molecules of phenol may be adsor bed in mixed style of vertical and flat orientation on the carbon's su rface in low concentration range, but in vertical possition mainly at high concentrations. However, o-cresol may be adsorbed in flat orienta tion at low temperatures, but in a same way as phenol at high temperat ures. The thermodynamics of the systems relates closely to the adsorpt ion mechanisms, and when vertical adsorption occurring, the entropy ch ange will be smaller. While, when flat adsorption occurring, the entro py change will be larger. Furthermore, some results of other solid-liq uid adsorption systems in the literatures have also been discussed.