Thermodynamics of Phenol Adsorption onto Activated Carbon Fiber

Abstract

The adsorption of phenol onto activated carbon fiber (ACF) from aqueous solutions were studied. The adsorption isotherms of phenol onto ACF at 298.15 K,303.15 K and 308.15K follow the Freundlich and Langmuir isotherm equation. The Freundlich model was verified to be the best to describe the adsorption data.Values of ∆G 0 for phenol adsorption onto ACF are-8.549、-7.899 and -7.516 kJ•mol-1 at 298.15,303.15and 308.15K , respectively. The values of ∆H 0 and ∆S 0 are -39.30 kJ•mol-1 and -103.3 J.mol-1.k-1, respectively. The adsorption process is spontaneous and exothermic. Negative △S 0 values suggested the randomness of phenol molecules at solid-liquid interface and an decrease in the degree of freedom of the adsorbed species.