Heat treatment of rockrose char in air. Effect on surface chemistry and porous texture

✍ Scribed by V. Gomez-Serrano; J. Pastor-Villegas; C.J. Duran-Valle; C. Valenzuela-Calahorro

• Publisher: Elsevier Science
• Year: 1996
• Tongue: English
• Weight: 640 KB
• Volume: 34
• Category: Article
• ISSN: 0008-6223
• DOI: 10.1016/0008-6223(96)00001-2

✦ Synopsis

The surface chemistry and the porous texture of activated carbons prepared from a charred product (C,,,-600), which was obtained from rockrose (Cistus ladaniferus, L.) extracted previously into petroleum ether, were studied. Activated carbons were prepared by heating C,,,-600 between 350 and 850°C in air to 40% burnoff. Methods of chemical analysis and FTIR spectroscopy as well as techniques of gas adsorption (N2, 77 K; CO,, 298 K), mercury porosimetry, and density measurements were applied. In the FTIR study of the samples, the presence of surface olefinic C=C double bonds, aromatic rings, and oxygen functional groups was detected. Carbonyl groups were only found to a significant extent in C,,,-600 and in the activated carbon prepared at 350°C. The microporosity developed with increasing temperature between 350 and 75O'C. At higher temperatures, pore narrowings occurred. The gasifying action of air was strongly dependent on the removal of nonorganized matter from C,,,-600 and on the pore size. The reaction time needed at 850°C in air to reach burnoff 40% was less than a half of that at 350°C and was comparable to the times required in CO, and steam under the same experimental conditions.