Adsorption and Diffusion of Nitrogen, Oxygen, Argon, and Methane in MolecularSieve Carbon at Elevated Pressures

摘要

Diffusion and equilibrium adsorption of nitrogen, oxygen, argon, and methane onmolecular sieve carbons 3A and 5A were studied at 237, 303, and 323 K. The adsorbate pressure was varied over a pressure range of 0-1.3 MPa in a gravimetric setup. On a molar basis, methane has the highest adsorption capacity among the four gases studied. Oxygen and nitrogen had approximately similar equilibrium adsorption capacity. Equilibrium adsorption data were represented by the Langmuir model and the vacancy solution model (VSM). Langmuir equation showed deviations at high pressures. The isosteric heat of adsorption was found to increase slightly with an increase in surface coverage. Kinetic data showed that oxygen had the highest diffusion rate and methane the lowest. Diffusivities were found to be generally independent of pressure.