Adsorption equilibrium and kinetics of CO₂, CH₄, N₂O, and NH₃ on ordered mesoporous carbon

Ordered mesoporous carbon was synthesized by a self-assembly technique and characterized with TEM, Raman spectroscopy, and nitrogen adsorption/desorption for its physical and pore textural properties. The high BET specific surface area (798m²/g), uniform mesopore-size distribution with a median pore size of 62.6Å, and large pore volume (0.87cm³/g) make the ordered mesoporous carbon an ideal adsorbent for gas separation and purification applications. Adsorption equilibrium and kinetics of carbon dioxide, methane, nitrous oxide, and ammonia on the ordered mesoporous carbon were measured at 298K and gas pressures up to 800Torr. The adsorption equilibrium capacities on the ordered mesoporous carbon at 298K and 800Torr for ammonia, carbon dioxide, nitrous oxide, and methane were found to be 6.39, 2.39, 1.5, and 0.53mmol/g, respectively. Higher adsorption uptakes of methane (3.26mmol/g at 100bar) and carbon dioxide (2.21mmol/g at 13bar) were also observed at 298K and elevated pressures. Langmuir, Freundlich, and Toth adsorption equilibrium models were used to correlate all the adsorption isotherms, and a simplified gas diffusion model was applied to analyze the adsorption kinetics data collected at 298K and four different gas pressures up to 800Torr.