Nitrogen Adsorption Studies of Novel Synthetic Active Carbons

Synthetic active carbons obtained via controlled carbonization of phenolic resins were characterized using low temperature nitrogen adsorption over a wide pressure range. It was shown that, although active carbons under study show appreciable differences in the BET specific surface area and the total pore volume, they exhibit quite similar porous properties. All samples were shown to possess a considerable amount of small micropores (ca. 0.7 nm). However, the active carbons have markedly different amounts of larger micropores (width above ca. 1 nm) and mesopores. It was shown that simple comparative methods, such as the high resolution αsplot, provide valuable information about structural properties of active carbons. However, reliable adsorption data for suitable reference adsorbents need to be available in order to successfully apply the comparative methods. Therefore, a nitrogen adsorption isotherm was measured on a Cabot BP 280 nongraphitized carbon black over a relative pressure range from 10−6to 0.99 and the resulting data (104 points) are reported in a tabular form. In the high pressure region (relative pressure from 0.1 to 0.7), the isotherm for the BP 280 sample exhibits a good agreement with the reference data available in the literature. Moreover, the adsorption isotherm currently reported covers the low pressure range, which is crucial in profound characterization of porous and nonporous solids by means of comparative methods of adsorption analysis.