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International Journal of Chemical Engineering
Volume 2014, Article ID 916913, 7 pages
http://dx.doi.org/10.1155/2014/916913
Research Article

Comparative Study of Textural Characteristics on Methane Adsorption for Carbon Spheres Produced by CO2 Activation

Department of Chemical Engineering, Sichuan University, Chengdu 610065, China

Received 13 February 2014; Revised 3 June 2014; Accepted 3 June 2014; Published 17 June 2014

Academic Editor: Dmitry Murzin

Copyright © 2014 Wen Yang et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Abstract

Resorcinol-formaldehyde resin polymer was used as raw material for preparation of carbon spheres. Samples were treated with CO2 flow at 850°C by varying activation times. The CO2 activation granted better pore development of pore structure. The experimental data of CH4 adsorption as a function of equilibrium pressure was fitted by Langmuir and Dubinin-Astakhov (D-A) models. It was concluded that the high surface area and micropore volume of carbon spheres did unequivocally determine methane capacities. In addition, a thermodynamic study of the heat of adsorption of CH4 on the carbon spheres was carried out. Adsorption of CH4 on carbon spheres showed a decrease in the adsorption heat with CH4 occupancy, and the heat of adsorption fell from 20.51 to 12.50 kJ/mol at 298 K and then increased to a little higher values at a very high loading (>0.70), indicating that CH4/CH4 interactions within the adsorption layer became significant.