Separation of CO2 and N2 from CH4 is significantly important in natural gas upgrading, and capture/removal of CO 2, CH4 from air (N2) is essential to greenhouse gas emission control. Adsorption equilibrium and kinetics of CO2, CH4, and N2 on an ordered mesoporous carbon (OMC) sample were systematically investigated to evaluate its capability in the above two applications. The OMC was synthesized and characterized with TEM, TGA, small-angle XRD, and nitrogen adsorption/desorption measurements. Pure component adsorption isotherms of CO2, CH4, and N2 were measured at 278, 298, and 318 K and pressures up to 100 kPa, and correlated with the Langmuir model. These data were used to estimate the separation selectivities for CO2/CH4, CH4/N2, and CO2/N2 binary mixtures at different compositions and pressures according to the ideal adsorbed solution theory (IAST) model. At 278 K and 100 kPa, the predicted selectivities for equimolar CO2/CH 4, CH4/N2, and CO2/N2 are 3.4, 3.7, and 12.8, respectively; and the adsorption capacities for CH 4 and CO2 are 1.3 and 3.0 mmol/g, respectively. This is the first report of a versatile mesoporous material that displays both high selectivities and large adsorption capacities for separating CO 2/CH4, CH4/N2, and CO 2/N2 mixtures.
ASJC Scopus subject areas
- Environmental Chemistry