The comparison of experimental and calculated pore size distributions of activated carbons

Abstract

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, CO isotherms have been measured at 273 K on

Modelling of water adsorption by activated carbons: effects of microporous structure and oxygen content

“…Simultaneously, and provided that the access to the micropores is not restricted by external 'gate' effects, the PSD can also be derived from the enthalpies of immersion of the carbon into liquids with molecular dimensions between 0.4 and 1.5 nm. For the carbons considered in the present and the earlier studies, one observes a good correlation between the PSDs obtained from these two independent techniques [22].…”

“…Parameters E H 2 O ðIÞ and E H 2 O ðVÞ are related to the characteristic energy E o of the carbon, obtained with the benzene isotherm (Benzene is a non-specific reference vapour). As shown elsewhere [13][14][15][16][17]21], including modelling [22], E o is also an inverse function of the average pore size, L o . This indicates that both the specific and the non-specific contributions to water adsorption depend on the structure of the carbon.…”

“…A small correction has to be applied for the wetting of the external (non-microporous) surface S e of the carbon. Finally, studies based on the correlation between E o and the average micropore-width [21], the enthalpy of immersion of phenol from dilute aqueous solutions [3] and the modelling of CO 2 adsorption [22], show that the actual surface area of the micropore walls S mi can be estimated with a good approximation.…”

“…As described previously [22], the PSD of a microporous carbon can be obtained from the analysis of the CO 2 adsorption isotherm at 273 K, using model isotherms. The latter are obtained from Monte Carlo simulations, assuming slit-shaped micropores.…”

Contributions of hemicellulose, cellulose and lignin to the mass and the porous properties of chars and steam activated carbons from various lignocellulosic precursors

“…Following a procedure described in detail in a previous work , CO 2 isotherms at high pressure were also measured at 0°C, in order to determine the pore size distributions (PSD) of the activated materials built using a method based on model isotherms resulting from molecular simulations already described in previous publications (Stoeckli et al, 1999(Stoeckli et al, , 2002.…”