Nicholas P Stadie, Maxwell Murialdo, Channing C Ahn, Brent Fultz
W. M. Keck Laboratory, California Institute of Technology, 138-78, Pasadena, California 91125, USA. nstadie@caltech.edu
Journal of the American Chemical Society 2013 Jan 23A thermodynamic study of the enthalpy of adsorption of methane on high surface area carbonaceous materials was carried out from 238 to 526 K. The absolute quantity of adsorbed methane as a function of equilibrium pressure was determined by fitting isotherms to a generalized Langmuir-type equation. Adsorption of methane on zeolite-templated carbon, an extremely high surface area material with a periodic arrangement of narrow micropores, shows an increase in isosteric enthalpy with methane occupancy; i.e., binding energies are greater as adsorption quantity increases. The heat of adsorption rises from 14 to 15 kJ/mol at near-ambient temperature and then falls to lower values at very high loading (above a relative site occupancy of 0.7), indicating that methane/methane interactions within the adsorption layer become significant. The effect seems to be enhanced by a narrow pore-size distribution centered at 1.2 nm, approximately the width of two monolayers of methane, and reversible methane delivery increases by up to 20% over MSC-30 at temperatures and pressures near ambient.
Nicholas P Stadie, Maxwell Murialdo, Channing C Ahn, Brent Fultz. Anomalous isosteric enthalpy of adsorption of methane on zeolite-templated carbon. Journal of the American Chemical Society. 2013 Jan 23;135(3):990-3
PMID: 23259456
View Full Text