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2013-09-29 - Colloque/Présentation - communication orale - Anglais - 1 page(s)

Billemont Pierre , Coasne Benoit, De Weireld Guy , "Adsorption of carbon dioxide, methane and their mixture in porous carbons: Effect of surface chemistry, pore disorder and water content" in ICCST 2013, International Conference on Coal Science and Technology, Pennsylvania, USA, 2013

  • Codes CREF : Recherche énergétique (DI2290), Chimie des surfaces et des interfaces (DI1327)
  • Unités de recherche UMONS : Thermodynamique, Physique mathématique (F506)
  • Instituts UMONS : Institut de Recherche en Energétique (Energie)

Abstract(s) :

(Anglais) Before modeling and making predictions for practical field applications such as carbon dioxide capture and storage (CCS) or Enhanced Coalbed Methane (ECBM), it is crucial to understand the adsorption behavior of carbon dioxide and methane in porous carbons. In particular, understanding the effect of the the presence of water on their phase diagram upon confinement is crucial [1,2]. To this end, the adsorption of carbon dioxide, methane and their mixtures in an activated carbon F400 in the presence of water has been studied using experiment and molecular simulation. Grand canonical Monte Carlo simulations are used in a disordered model built by a constrained Reverse Monte Carlo method [2]. Its surface chemistry has been modified to allow adsorption of water. The sorbent model is first characterized by nitrogen adsorption at 77K. The water adsorption isotherms are in fair agreement although the micropore filling occurred at higher pressure in the simulation. The adsorption isotherms for carbon dioxide and methane are obtained for four different loadings of water (0.43, 1.97, 5.20 and 12.61 mmol.g-1). At low amounts of adsorbed water, both simulations and experiments show a slight decrease in the adsorption capacities of methane and carbon dioxide but the shape of the adsorption isotherms remains unchanged. At high amount of adsorbed water, experiments suggest the occurrence of a phase change during methane and carbon dioxide adsorption. The difference in behavior is attributed to the difference in structure between the model and the sorbent. These simulations show that molecules of water leave the sample during carbon dioxide and methane adsorption. The number of molecules of water leaving the adsorbed phase increases with the pressure of carbon dioxide and methane. In contrast, experimentally, the water does not seem to be desorbed during subsequent adsorption of carbon dioxide and methane. Methane and CO2 coadsorption in a realistic model of disordered porous carbon in the presence of water. The grey sticks are the segments between carbon atoms. The yellow spheres are methane molecules. The red and white spheres are the oxygen and hydrogen atoms of the water and CO2 molecules or of the porous carbon. The blue spheres are the C atoms of the CO2 molecules. [1] P. Billemont, B. Coasne and G. De Weireld, Langmuir, 27 (3), 1015–1024 (2011). [2] P. Billemont, B. Coasne and G. De Weireld, Langmuir, doi: 10.1021/la3048938. [3] S. K. Jain, J. P. Pikunic, R. J.-M. Pellenq and K. E. Gubbins, Adsorption, 11, 355-360 (2005).