Changes in pore properties of phenol formaldehyde-based carbon with carbonization and oxidation conditions

• Published in: Carbon (New York) 2002-09, Vol.40 (11), p.2003-2012
• Main Authors: Kim, Myung Il, Yun, Chang Hun, Kim, Young Jeon, Park, Chong Rae, Inagaki, Michio
• Format: Article
• Language: English
• Subjects: A. Carbon beads; B. Carbonization; C. Adsorption; Chemistry; Colloidal state and disperse state; D. Surface properties; Exact sciences and technology; General and physical chemistry; Porous materials; Surface treatment
• ISSN: 0008-6223; 1873-3891
• DOI: 10.1016/S0008-6223(02)00058-1

Porous carbon beads were prepared by carbonizing at 700 and 1000 °C under N 2 (NN-series) or CO 2 atmospheres (CO-series) and a subsequent oxidization with boiling nitric acid solution (13%, v/v) for 3 h (ANN- and ACO-series). BET surface area of both CO- and NN-series samples tends to increase with increasing carbonization temperature, but CO-series samples show higher BET surface areas (700 °C: 610 m 2/g, 1000 °C: 780 m 2/g) compared with those of NN-series samples (700 °C: 380 m 2/g, 1000 °C: 580 m 2/g). After acid oxidation, BET surface areas of NN-series samples increased from 580 to 650 m 2/g, whereas those of CO-series samples decreased from 780 to 600 m 2/g. On subsequent acid oxidation, acidic surface functional groups increased in both CO- and NN-series samples, but the CO-series samples tend to have much more acidic surface functional groups. Adsorption of halogenated methanes, such as tetra-, tri- and dichloromethanes, onto the samples of CO-, NN-, ACO- and ANN-series was thought to be driven initially by the basicity, but the acidic functional groups that could attract adsorbates via dipole–dipole interaction might hinder the adsorption of subsequently incoming adsorbates.