Sieving Properties of Carbons Obtained by Template Carbonization of Polyfurfuryl Alcohol within Mineral Matrixes

Carbons obtained by carbonization of polyfurfuryl alcohol within the smectite and taeniolite matrices were studied by sorption methods. The sorption of nitrogen at 77 K showed only small differences in the pore structure ofthese materials related to the properties of the inorganic matrix. More specific information about pore structure was obtained from inverse gas chromatography, where molecules of different sizes were used to study sieving properties. Micropore structure was also studied by sorption of methane, carbon tetrafluoride, and sulfur hexafluoride at supercritical temperatures ; at these temperatures they are adsorbed mainly in small pores. Thermodynamic quantities, such as adsorption energy distribution, micropore size distribution, and isosteric heat of adsorption, were calculated assuming the energy distribution is governed by pore size distribution due to adsorption potential enhancement in small pores. The results obtained demonstrate the presence of sieving effects for molecular sizes between 3.6 and 6 A.