Determination of the adsorption volume and surface of carbon adsorbents with developed mesoporosity

The isotherms of excess adsorption of CH4 (at P = 0.001 - 160 MPa), SF6 (at P = 0.001-2.4 MPa), and C6H6 (at P = 0.0001-0.1 MPa) on carbon adsorbents - microporous carbons CMS and FAS with developed mesoporosity and graphitiz ed soot - were measured in the 298-408 K temperature region. Calculation of the isotherms of absolute adsorption of the total content of these substan ces requires knowledge of the adsorption volume, which was determined by di fferent methods: by the Dubinin-Radushkevich equation: by the experimental isotherm of excess adsorption and the equation of absolute adsorption: by t he method using the intersection of nonlinear isosteres of excess adsorptio n and isosteres of absolute adsorption; by the comparative plot of values o f the excess C6H6 adsorption Gamma(FAS)-Gamma(soot); by the method using th e difference of molecular radii of adsorptives and the surface of the speci fic adsorbent; and by the calculation of the adsorption layer thickness usi ng the FHH equation for mesoporous systems. The results of determination of the adsorption volume for microporous systems of these carbons agree well with each other and with the passport data for the adsorbents. Analysis of the results revealed the peculiarity of the sulfur hexafluoride adsorption related to the formation of associates on the surface of the carbon adsorbe nts.