RELATION BETWEEN TEXTURAL AND ENERGETIC PARAMETERS OF ACTIVATED CARBON MONOLITHS FROM COCONUT SHELLS

Structural characteristics and the energetic parameters of five monoliths of activated carbon were compared. The samples were obtained from coconut shells by means of chemical activation using different concentrations of phosphoric acid. The samples are characterized by means of physical adsorption of N-2 at 77K, CO2 at 273K, and immersion calorimetry in benzene. From the data obtained the volumes of micropore, mesopore, narrow microporosity and energy parameters of inmersion enthalpy were calculated. Also were calculated, K of the Langmuir model and characteristic energies, Eo, of the Dubinin-Radushkevich model. The experimental results show that the activation with phosphoric acid develops microporosity, giving a micropore volume between 0,36 and 0,45 cm(3)g(-1), area BET between 975 and 1320 m(2)g(-1) and immersion enthalpy between 112,9 and 147,7 Jg(-1). It was found that for higher BET area, there is a greater immersion enthalpy in benzene, lower characteristic energy and smaller value of K.