Voici les éléments 1 - 3 sur 3
  • Publication
    Accès libre
    Water adsorption by activated carbons in relation to their microporous structure
    (2003)
    Slasli, Abdou
    ;
    Jorge, M.
    ;
    ;
    Seaton, N. A.
    The present paper examines the adsorption of water by microporous carbons in the absence of specific interactions. The modelling of water adsorption for 293 and 310 K, using variable pore size distributions (PSD), shows that the type V isotherms follow the Dubinin–Astakhov (DA) equation and fulfill the requirement for temperature invariance. Furthermore, the parameters of the DA equation can be related in a simple way to structural properties of the model carbons. For a number of well-characterized carbons, the type V isotherms generated by combining model isotherms with the corresponding PSDs are in good agreement with the limiting isotherms at 293 and 310 K derived on the basis of a recent development of Dubinin’s theory. This approach will provide the basis for further studies including specific interactions.
  • Publication
    Accès libre
    Microporosity in carbon blacks
    (2002) ;
    Guillot, André
    ;
    Slasli, Abdou
    ;
    Hugi-Cleary, Deirdre
    Microporous carbon blacks can be characterized by the same techniques as activated carbons, using the classical DR equation and comparison plots based on non-porous materials. The CO2 adsorption isotherm at 273 K, combined with computer modelling, also leads to an assessment of microporosity. The results agree with independent techniques such as immersion calorimetry into liquids of variable molecular dimensions and a modified Dubinin equation. The study also confirms that the comparison plots based on N2 (77 K), CO2 (273 K) and C6H6 (293 K) do not necessarily lead to overlapping results for the total micropore volume and the external surface area of the carbons.
  • Publication
    Accès libre
    The comparison of experimental and calculated pore size distributions of activated carbons
    (2002) ;
    Guillot, André
    ;
    Slasli, Abdou
    ;
    Hugi-Cleary, Deirdre
    Activated carbons are disorganized materials with variable pore size distributions (PSD). If one assumes that the porosity consists mainly of locally slit-shaped micropores, model isotherms can be obtained by computer simulations and used to assess the PSD on the basis of experimental isotherms. In the present study, CO2 isotherms have been measured at 273 K on seven well-characterized microporous carbons with average micropore widths between 0.65 and 1.5 nm and analysed with model isotherms obtained with standard Monte Carlo simulations. The resulting PSD are in good agreement with those obtained from a modified Dubinin equation, from liquid probes of molecular dimensions between 0.4 and 1.5 nm, from STM and from modelling based on CH4 adsorption at 308 K. The present study validates the determination of micropore distributions in active carbons based on CO2 isotherms, provided that no gate effects are present.