Active surface area of microporous carbons

✍ Scribed by P. Ehrburger; N. Pusset; P. Dziedzinl

• Publisher: Elsevier Science
• Year: 1992
• Tongue: English
• Weight: 506 KB
• Volume: 30
• Category: Article
• ISSN: 0008-6223
• DOI: 10.1016/0008-6223(92)90142-j

✦ Synopsis

Three different types of carbon precursor-mesophase microbeads, preoxidized polyacrylonitrile (PAN) fibres, and phenolic fibres-have been carbonized in argon at 900°C and thereafter activated with carbon dioxide at the same temperature. Physical adsorption of nitrogen at -196°C and of carbon dioxide at 0°C has been carried out on the activated samples. Active surface area of carbons was determined using oxygen chemisorption at 3oo"C, followed by thermal programmed desorption of oxygen complexes. Micropore volume and mean pore width have been determined using the Dubinin-Radushkevich (DR) equation and the olg method. A relationship between V DR and active surface area (AU) is found during activation of mesophase carbon and PAN carbon fibres that are not microporous before activation. The ratio ASA to the micropore surface area remains almost constant during activation and has nearly the same value for all three samples. Changes in active surface area and in micropore volume are discussed in terms of microtexture development in carbons during gasification. The results emphasize the importance of the carbon precursor on the development of microporosity during activation. Kev Words-Microoorous texture. active surface area, activation, mesophase microbeads, PAN carbon fibie, phenolic carbon fibre.