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Stoeckli, Fritz

Nom
Stoeckli, Fritz
Affiliation principale
Fonction
Professeur.e émérite
Email
fritz.stoeckli@unine.ch
Identifiants
https://libra.unine.ch/handle/123456789/471

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  • Publication
    Accès libre
    Contributions of hemicellulose, cellulose and lignin to the mass and the porous properties of chars and steam activated carbons from various lignocellulosic precursors
    (2009)
    Cagnon, Benoît
    ;
    Py, Xavier
    ;
    Guillot, André
    ;
    Stoeckli, Fritz 
    ;
    Chambat, Gérard
    In this study, contributions of hemicellulose, cellulose and lignin to the mass and the porous properties of chars and activated carbons from various lignocellulosic materials were studied. A predictive calculation was established using the experimental results obtained for the three components separately to evaluate the carbonization and activation yields and their respective contributions to the chars and to the subsequent activated carbons of various precursors in term of weight fraction. These equations were validated. The results showed that lignin can be considering as being the major contributor of all chars and activated carbons. Besides, the evolution of the mean pore size versus the specific porous volume showed that each component contributes to the porosity of chars and activated carbons whatever is its weight contribution.
  • Publication
    Accès libre
    The effect of the carbonization/activation procedure on the microporous texture of the subsequent chars and active carbons
    (2003)
    Cagnon, Benoît
    ;
    Py, Xavier
    ;
    Guillot, André
    ;
    Stoeckli, Fritz 
    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.