PORE-SIZE DISTRIBUTION OF BPL ACTIVATED CARBON DETERMINED BY DIFFERENT METHODS

Current methods of obtaining pore size distributions (PSDs) of microporous carbons are based on the interpretation of gas adsorption measurements through adsorption equilibrium models. We examine the consistency of five such models by constructing PSDs of a single adsorbent, BPL activated carbon, from an N2 adsorption isotherm at 77 K and from water desorption isotherms at various temperatures. For each method the adsorbent is modeled as a collection of independent, parallel-sided, slit-shaped pores. The distributions confirm that BPL carbon is a predominantly microporous material, but the maxima in the differential volume distributions vary from pore widths of 5.9 to 18 angstrom. The variation among the distributions indicates a lack of consistency among the five gas adsorption models.