Faculté des sciences

The effect of the carbonization/activation procedure on the microporous texture of the subsequent chars and active carbons

Cagnon, Benoît ; Py, Xavier ; Guillot, André ; Stoeckli, Fritz

In: Microporous and Mesoporous Materials, 2003, vol. 57, no. 3, p. 273-282

Chars obtained by carbonizing coconut shells at different intermediate heat treatment temperatures (IHTT) between 400 and 800 °C were activated at 800 °C in a stream of N2+H2O, following two distinct procedures. In the first procedure, activation follows directly the carbonization, whereas in the second procedure, the sample was first brought back to 25 °C and... Plus

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    Summary
    Chars obtained by carbonizing coconut shells at different intermediate heat treatment temperatures (IHTT) between 400 and 800 °C were activated at 800 °C in a stream of N2+H2O, following two distinct procedures. In the first procedure, activation follows directly the carbonization, whereas in the second procedure, the sample was first brought back to 25 °C and subsequently heated again to the activation temperature of 800 °C. The data for CO2 adsorption at 25 °C and N2 at −196 °C with immersion calorimetry confirms that the activated carbons derived from chars obtained at low IHTT and in two steps, present a “gate effect” for burn-offs <20% or 25%, otherwise, the final carbons present similar structural characteristics for higher burn-offs. It also appears that the evolution of the average pore width L0 with the micropore volume W0 follows a general pattern outlined early.