Study of SO2 into nanoporous silica Y Zeolite: Molecular dynamics simulation

The dynamic, structure, and thermodynamic properties of sulfur dioxide guest gas inside nanoporous fixed silica Y zeolite were studied by molecular dynamics simulation at different loadings of SO2 per unit cell and within a range of temperature. At loading 20, greater deviation from Fickian behavior is observed. Generally, self-diffusion coefficient increases with temperature. The activation energy for diffusion follows a decreasing trend by loading increase, except at loading 20, which shows an increase in activation energy. The velocity auto-correlation function demonstrates oscillating behavior and cage effect decrease with temperature. From the radial distribution function (RDF) between gas and zeolite framework, it is found that the first layer around the central atom at a low temperature is established more easily and the first peak of the RDF appears at a short distance with more intensity. The interaction between S and Si atoms was examined by the potential of mean force that is independent of loading. The results indicate that SO2 is able to disperse homogeneously into the zeolite at all concentrations and temperatures without much perturbation.