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The incorporation of oxygen functional groups onto the surface of eucalyptus activated carbon and its surface chemistry were investigated as a function of oxidation conditions, carbon porous properties and carbon preparation method. Under all treatment conditions of increasing time, temperature and oxidant concentration, liquid oxidation with HNO 3 , H 2 O 2 and (NH 4 ) 2 S 2 O 8 and air oxidation led to the increase of acidic group concentration, with carboxylic acid showing the largest percentage increase and air oxidation at the maximum allowable temperature of 350 o C produced the maximum content of both carboxylic acid and total acidic group. Nitric acid oxidation of chemically activated carbon produced higher total acidic content but a lower amount of carboxylic acid compared to the oxidized carbon from physical activation. The increased contents of acidic groups on oxidized carbons greatly enhanced the adsorption capacity of water vapor and heavy metal ions.

Solid chars were prepared from coconut shell at different carbonization temperatures in the range from 250-750°C and gasified in a thermogravimetric analyzer under the atmosphere of carbon dioxide at 850 o C. The kinetic analysis showed an accelerating increasing of char conversion with reaction time, indicating an increase in the instantaneous gasification rate as the reaction proceeded. Four kinetic models for gas-solid reactions including, the volume-reaction model (VRM), the shrinking-core model (SCM), the random-pore model (RPM) and the modified volume-reaction model (MVRM) were tested against the measured kinetic data and the MVRM was found to predict the gasification kinetics most accurately. The char reactivity index was computed from the apparent rate constant of the MVRM and used to assess the reactivity of char towards carbon dioxide gasification. It was found that the char reactivity index decreased with increasing carbonization temperature, with the char produced at the lowest temperature of 250°C giving the highest reactivity. Surface area of activated carbon, produced from the gasification of various chars at 850°C for 60 and 120 min, correlated well with the char reactivity index, showing a proportional increasing of surface area with increasing reactivity index and passing through a maximum near the reactivity index of 0.02 min-1 .