Molecular simulation of MCM-41: Structural properties and adsorption of CO2, N2 and flue gas

To investigate structural and adsorption properties of the MCM-41 molecular model more correctly, two effective MCM-41 models were built. The structural and morphological features of two atomistic models were systematically analyzed in terms of pore size distribution (PSD), X-ray diffraction (XRD), atomic relative concentration, partial radial distribution (RDF), ring distribution, pore surface smoothness, etc. Furthermore, the adsorption isotherms and isosteric heats of pure N-2, CO2 and their mixture as flue gas (12% CO2 and 88% N-2) adsorbed in MCM-41 models were calculated based on grand canonical Monte Carlo (GCMC) simulation. The simulated results were in good agreement with experimental ones. Finally, adsorbate morphology, adsorbed density and adsorbate location distribution were properly described by molecular simulation. The result confirmed the competitive adsorption behavior of CO2 over N-2 and clearly revealed the microscopic detail: CO2 adsorption mainly depended on the surface functional group while N-2 adsorption depended on the available pore volume. The proposed MCM-41 models can be used to guide further molecular designs for novel amine-functionalized MCM-41 adsorbents. (C) 2013 Elsevier B.V. All rights reserved.